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authorGravatar Abseil Team <absl-team@google.com>2019-07-17 16:35:47 -0400
committerGravatar Derek Mauro <dmauro@google.com>2019-07-17 16:40:57 -0400
commitc6c3c1b498e4ee939b24be59cae29d59c3863be8 (patch)
tree030b875cdbbd25d2d0b7bca0b68a71351eeb2c41 /absl
parent44efe96dfca674a17b45ca53fc77fb69f1e29bf4 (diff)
Export of internal Abseil changes.
-- ed3a3431eee9e48e6553b0320e0308d2dde6725c by Derek Mauro <dmauro@google.com>: Project import generated by Copybara. PiperOrigin-RevId: 258631680 GitOrigin-RevId: ed3a3431eee9e48e6553b0320e0308d2dde6725c Change-Id: I1d7ae86a79783842092d29504605ba039c369603
Diffstat (limited to 'absl')
-rw-r--r--absl/base/spinlock_test_common.cc2
-rw-r--r--absl/container/BUILD.bazel3
-rw-r--r--absl/container/CMakeLists.txt3
-rw-r--r--absl/container/internal/common.h23
-rw-r--r--absl/container/internal/compressed_tuple.h49
-rw-r--r--absl/container/internal/compressed_tuple_test.cc201
-rw-r--r--absl/container/internal/hashtablez_sampler.cc2
-rw-r--r--absl/container/internal/raw_hash_set.h2
-rw-r--r--absl/container/internal/test_instance_tracker.h2
-rw-r--r--absl/flags/BUILD.bazel23
-rw-r--r--absl/flags/CMakeLists.txt21
-rw-r--r--absl/flags/flag.cc26
-rw-r--r--absl/flags/flag.h51
-rw-r--r--absl/flags/internal/commandlineflag.cc439
-rw-r--r--absl/flags/internal/commandlineflag.h76
-rw-r--r--absl/flags/internal/commandlineflag_test.cc14
-rw-r--r--absl/flags/internal/flag.h72
-rw-r--r--absl/flags/internal/registry.cc54
-rw-r--r--absl/flags/internal/type_erased.cc19
-rw-r--r--absl/flags/internal/usage.cc38
-rw-r--r--absl/flags/internal/usage.h7
-rw-r--r--absl/flags/internal/usage_test.cc38
-rw-r--r--absl/flags/parse.cc25
-rw-r--r--absl/hash/hash_test.cc1
-rw-r--r--absl/hash/internal/hash.h3
-rw-r--r--absl/numeric/int128.h4
-rw-r--r--absl/random/internal/fast_uniform_bits.h349
-rw-r--r--absl/random/internal/fast_uniform_bits_test.cc241
-rw-r--r--absl/strings/str_join.h5
-rw-r--r--absl/synchronization/internal/create_thread_identity.cc3
-rw-r--r--absl/time/time.h5
31 files changed, 1152 insertions, 649 deletions
diff --git a/absl/base/spinlock_test_common.cc b/absl/base/spinlock_test_common.cc
index e62b2eae..84fc4dac 100644
--- a/absl/base/spinlock_test_common.cc
+++ b/absl/base/spinlock_test_common.cc
@@ -62,7 +62,6 @@ static SpinLock static_cooperative_spinlock(
static SpinLock static_noncooperative_spinlock(
base_internal::kLinkerInitialized, base_internal::SCHEDULE_KERNEL_ONLY);
-
// Simple integer hash function based on the public domain lookup2 hash.
// http://burtleburtle.net/bob/c/lookup2.c
static uint32_t Hash32(uint32_t a, uint32_t c) {
@@ -194,6 +193,7 @@ TEST(SpinLock, WaitCyclesEncoding) {
TEST(SpinLockWithThreads, StaticSpinLock) {
ThreadedTest(&static_spinlock);
}
+
TEST(SpinLockWithThreads, StackSpinLock) {
SpinLock spinlock;
ThreadedTest(&spinlock);
diff --git a/absl/container/BUILD.bazel b/absl/container/BUILD.bazel
index 17d725c1..b8cf17fc 100644
--- a/absl/container/BUILD.bazel
+++ b/absl/container/BUILD.bazel
@@ -44,7 +44,10 @@ cc_test(
linkopts = ABSL_DEFAULT_LINKOPTS,
deps = [
":compressed_tuple",
+ ":test_instance_tracker",
"//absl/memory",
+ "//absl/types:any",
+ "//absl/types:optional",
"//absl/utility",
"@com_google_googletest//:gtest_main",
],
diff --git a/absl/container/CMakeLists.txt b/absl/container/CMakeLists.txt
index 6df331e1..5d7c75dd 100644
--- a/absl/container/CMakeLists.txt
+++ b/absl/container/CMakeLists.txt
@@ -43,8 +43,11 @@ absl_cc_test(
COPTS
${ABSL_TEST_COPTS}
DEPS
+ absl::any
absl::compressed_tuple
absl::memory
+ absl::optional
+ absl::test_instance_tracker
absl::utility
gmock_main
)
diff --git a/absl/container/internal/common.h b/absl/container/internal/common.h
index b06e7113..591d3ea1 100644
--- a/absl/container/internal/common.h
+++ b/absl/container/internal/common.h
@@ -77,10 +77,18 @@ class node_handle_base {
protected:
friend struct CommonAccess;
- node_handle_base(const allocator_type& a, slot_type* s) : alloc_(a) {
+ struct transfer_tag_t {};
+ node_handle_base(transfer_tag_t, const allocator_type& a, slot_type* s)
+ : alloc_(a) {
PolicyTraits::transfer(alloc(), slot(), s);
}
+ struct move_tag_t {};
+ node_handle_base(move_tag_t, const allocator_type& a, slot_type* s)
+ : alloc_(a) {
+ PolicyTraits::construct(alloc(), slot(), s);
+ }
+
void destroy() {
if (!empty()) {
PolicyTraits::destroy(alloc(), slot());
@@ -121,7 +129,7 @@ class node_handle : public node_handle_base<PolicyTraits, Alloc> {
private:
friend struct CommonAccess;
- node_handle(const Alloc& a, typename Base::slot_type* s) : Base(a, s) {}
+ using Base::Base;
};
// For maps.
@@ -148,7 +156,7 @@ class node_handle<Policy, PolicyTraits, Alloc,
private:
friend struct CommonAccess;
- node_handle(const Alloc& a, typename Base::slot_type* s) : Base(a, s) {}
+ using Base::Base;
};
// Provide access to non-public node-handle functions.
@@ -164,8 +172,13 @@ struct CommonAccess {
}
template <typename T, typename... Args>
- static T Make(Args&&... args) {
- return T(std::forward<Args>(args)...);
+ static T Transfer(Args&&... args) {
+ return T(typename T::transfer_tag_t{}, std::forward<Args>(args)...);
+ }
+
+ template <typename T, typename... Args>
+ static T Move(Args&&... args) {
+ return T(typename T::move_tag_t{}, std::forward<Args>(args)...);
}
};
diff --git a/absl/container/internal/compressed_tuple.h b/absl/container/internal/compressed_tuple.h
index c29ab41e..7d08e370 100644
--- a/absl/container/internal/compressed_tuple.h
+++ b/absl/container/internal/compressed_tuple.h
@@ -102,7 +102,9 @@ template <typename T, size_t I,
struct Storage {
T value;
constexpr Storage() = default;
- explicit constexpr Storage(T&& v) : value(absl::forward<T>(v)) {}
+ template <typename V>
+ explicit constexpr Storage(absl::in_place_t, V&& v)
+ : value(absl::forward<V>(v)) {}
constexpr const T& get() const& { return value; }
T& get() & { return value; }
constexpr const T&& get() const&& { return absl::move(*this).value; }
@@ -112,7 +114,11 @@ struct Storage {
template <typename T, size_t I>
struct ABSL_INTERNAL_COMPRESSED_TUPLE_DECLSPEC Storage<T, I, true> : T {
constexpr Storage() = default;
- explicit constexpr Storage(T&& v) : T(absl::forward<T>(v)) {}
+
+ template <typename V>
+ explicit constexpr Storage(absl::in_place_t, V&& v)
+ : T(absl::forward<V>(v)) {}
+
constexpr const T& get() const& { return *this; }
T& get() & { return *this; }
constexpr const T&& get() const&& { return absl::move(*this); }
@@ -132,8 +138,9 @@ struct ABSL_INTERNAL_COMPRESSED_TUPLE_DECLSPEC CompressedTupleImpl<
: uses_inheritance,
Storage<Ts, std::integral_constant<size_t, I>::value>... {
constexpr CompressedTupleImpl() = default;
- explicit constexpr CompressedTupleImpl(Ts&&... args)
- : Storage<Ts, I>(absl::forward<Ts>(args))... {}
+ template <typename... Vs>
+ explicit constexpr CompressedTupleImpl(absl::in_place_t, Vs&&... args)
+ : Storage<Ts, I>(absl::in_place, absl::forward<Vs>(args))... {}
friend CompressedTuple<Ts...>;
};
@@ -143,8 +150,9 @@ struct ABSL_INTERNAL_COMPRESSED_TUPLE_DECLSPEC CompressedTupleImpl<
// We use the dummy identity function as above...
: Storage<Ts, std::integral_constant<size_t, I>::value, false>... {
constexpr CompressedTupleImpl() = default;
- explicit constexpr CompressedTupleImpl(Ts&&... args)
- : Storage<Ts, I, false>(absl::forward<Ts>(args))... {}
+ template <typename... Vs>
+ explicit constexpr CompressedTupleImpl(absl::in_place_t, Vs&&... args)
+ : Storage<Ts, I, false>(absl::in_place, absl::forward<Vs>(args))... {}
friend CompressedTuple<Ts...>;
};
@@ -159,6 +167,11 @@ constexpr bool ShouldAnyUseBase() {
Or({std::integral_constant<bool, ShouldUseBase<Ts>()>()...})){};
}
+template <typename T, typename V>
+using TupleMoveConstructible = typename std::conditional<
+ std::is_reference<T>::value, std::is_convertible<V, T>,
+ std::is_constructible<T, V&&>>::type;
+
} // namespace internal_compressed_tuple
// Helper class to perform the Empty Base Class Optimization.
@@ -192,9 +205,29 @@ class ABSL_INTERNAL_COMPRESSED_TUPLE_DECLSPEC CompressedTuple
using StorageT = internal_compressed_tuple::Storage<ElemT<I>, I>;
public:
+ // There seems to be a bug in MSVC dealing in which using '=default' here will
+ // cause the compiler to ignore the body of other constructors. The work-
+ // around is to explicitly implement the default constructor.
+#if defined(_MSC_VER)
+ constexpr CompressedTuple() : CompressedTuple::CompressedTupleImpl() {}
+#else
constexpr CompressedTuple() = default;
- explicit constexpr CompressedTuple(Ts... base)
- : CompressedTuple::CompressedTupleImpl(absl::forward<Ts>(base)...) {}
+#endif
+ explicit constexpr CompressedTuple(const Ts&... base)
+ : CompressedTuple::CompressedTupleImpl(absl::in_place, base...) {}
+
+ template <typename... Vs,
+ absl::enable_if_t<
+ absl::conjunction<
+ // Ensure we are not hiding default copy/move constructors.
+ absl::negation<std::is_same<void(CompressedTuple),
+ void(absl::decay_t<Vs>...)>>,
+ internal_compressed_tuple::TupleMoveConstructible<
+ Ts, Vs&&>...>::value,
+ bool> = true>
+ explicit constexpr CompressedTuple(Vs&&... base)
+ : CompressedTuple::CompressedTupleImpl(absl::in_place,
+ absl::forward<Vs>(base)...) {}
template <int I>
ElemT<I>& get() & {
diff --git a/absl/container/internal/compressed_tuple_test.cc b/absl/container/internal/compressed_tuple_test.cc
index 3b0ec455..19af8f10 100644
--- a/absl/container/internal/compressed_tuple_test.cc
+++ b/absl/container/internal/compressed_tuple_test.cc
@@ -19,7 +19,10 @@
#include "gmock/gmock.h"
#include "gtest/gtest.h"
+#include "absl/container/internal/test_instance_tracker.h"
#include "absl/memory/memory.h"
+#include "absl/types/any.h"
+#include "absl/types/optional.h"
#include "absl/utility/utility.h"
// These are declared at global scope purely so that error messages
@@ -43,10 +46,14 @@ struct TwoValues {
U value2;
};
+
namespace absl {
namespace container_internal {
namespace {
+using absl::test_internal::CopyableMovableInstance;
+using absl::test_internal::InstanceTracker;
+
TEST(CompressedTupleTest, Sizeof) {
EXPECT_EQ(sizeof(int), sizeof(CompressedTuple<int>));
EXPECT_EQ(sizeof(int), sizeof(CompressedTuple<int, Empty<0>>));
@@ -62,6 +69,141 @@ TEST(CompressedTupleTest, Sizeof) {
sizeof(CompressedTuple<int, Empty<0>, NotEmpty<double>, Empty<1>>));
}
+TEST(CompressedTupleTest, OneMoveOnRValueConstructionTemp) {
+ InstanceTracker tracker;
+ CompressedTuple<CopyableMovableInstance> x1(CopyableMovableInstance(1));
+ EXPECT_EQ(tracker.instances(), 1);
+ EXPECT_EQ(tracker.copies(), 0);
+ EXPECT_LE(tracker.moves(), 1);
+ EXPECT_EQ(x1.get<0>().value(), 1);
+}
+
+TEST(CompressedTupleTest, OneMoveOnRValueConstructionMove) {
+ InstanceTracker tracker;
+
+ CopyableMovableInstance i1(1);
+ CompressedTuple<CopyableMovableInstance> x1(std::move(i1));
+ EXPECT_EQ(tracker.instances(), 2);
+ EXPECT_EQ(tracker.copies(), 0);
+ EXPECT_LE(tracker.moves(), 1);
+ EXPECT_EQ(x1.get<0>().value(), 1);
+}
+
+TEST(CompressedTupleTest, OneMoveOnRValueConstructionMixedTypes) {
+ InstanceTracker tracker;
+ CopyableMovableInstance i1(1);
+ CopyableMovableInstance i2(2);
+ Empty<0> empty;
+ CompressedTuple<CopyableMovableInstance, CopyableMovableInstance&, Empty<0>>
+ x1(std::move(i1), i2, empty);
+ EXPECT_EQ(x1.get<0>().value(), 1);
+ EXPECT_EQ(x1.get<1>().value(), 2);
+ EXPECT_EQ(tracker.copies(), 0);
+ EXPECT_EQ(tracker.moves(), 1);
+}
+
+struct IncompleteType;
+CompressedTuple<CopyableMovableInstance, IncompleteType&, Empty<0>>
+MakeWithIncomplete(CopyableMovableInstance i1,
+ IncompleteType& t, // NOLINT
+ Empty<0> empty) {
+ return CompressedTuple<CopyableMovableInstance, IncompleteType&, Empty<0>>{
+ std::move(i1), t, empty};
+}
+
+struct IncompleteType {};
+TEST(CompressedTupleTest, OneMoveOnRValueConstructionWithIncompleteType) {
+ InstanceTracker tracker;
+ CopyableMovableInstance i1(1);
+ Empty<0> empty;
+ struct DerivedType : IncompleteType {int value = 0;};
+ DerivedType fd;
+ fd.value = 7;
+
+ CompressedTuple<CopyableMovableInstance, IncompleteType&, Empty<0>> x1 =
+ MakeWithIncomplete(std::move(i1), fd, empty);
+
+ EXPECT_EQ(x1.get<0>().value(), 1);
+ EXPECT_EQ(static_cast<DerivedType&>(x1.get<1>()).value, 7);
+
+ EXPECT_EQ(tracker.copies(), 0);
+ EXPECT_EQ(tracker.moves(), 2);
+}
+
+TEST(CompressedTupleTest,
+ OneMoveOnRValueConstructionMixedTypes_BraceInitPoisonPillExpected) {
+ InstanceTracker tracker;
+ CopyableMovableInstance i1(1);
+ CopyableMovableInstance i2(2);
+ CompressedTuple<CopyableMovableInstance, CopyableMovableInstance&, Empty<0>>
+ x1(std::move(i1), i2, {}); // NOLINT
+ EXPECT_EQ(x1.get<0>().value(), 1);
+ EXPECT_EQ(x1.get<1>().value(), 2);
+ EXPECT_EQ(tracker.instances(), 3);
+ // We are forced into the `const Ts&...` constructor (invoking copies)
+ // because we need it to deduce the type of `{}`.
+ // std::tuple also has this behavior.
+ // Note, this test is proof that this is expected behavior, but it is not
+ // _desired_ behavior.
+ EXPECT_EQ(tracker.copies(), 1);
+ EXPECT_EQ(tracker.moves(), 0);
+}
+
+TEST(CompressedTupleTest, OneCopyOnLValueConstruction) {
+ InstanceTracker tracker;
+ CopyableMovableInstance i1(1);
+
+ CompressedTuple<CopyableMovableInstance> x1(i1);
+ EXPECT_EQ(tracker.copies(), 1);
+ EXPECT_EQ(tracker.moves(), 0);
+
+ tracker.ResetCopiesMovesSwaps();
+
+ CopyableMovableInstance i2(2);
+ const CopyableMovableInstance& i2_ref = i2;
+ CompressedTuple<CopyableMovableInstance> x2(i2_ref);
+ EXPECT_EQ(tracker.copies(), 1);
+ EXPECT_EQ(tracker.moves(), 0);
+}
+
+TEST(CompressedTupleTest, OneMoveOnRValueAccess) {
+ InstanceTracker tracker;
+ CopyableMovableInstance i1(1);
+ CompressedTuple<CopyableMovableInstance> x(std::move(i1));
+ tracker.ResetCopiesMovesSwaps();
+
+ CopyableMovableInstance i2 = std::move(x).get<0>();
+ EXPECT_EQ(tracker.copies(), 0);
+ EXPECT_EQ(tracker.moves(), 1);
+}
+
+TEST(CompressedTupleTest, OneCopyOnLValueAccess) {
+ InstanceTracker tracker;
+
+ CompressedTuple<CopyableMovableInstance> x(CopyableMovableInstance(0));
+ EXPECT_EQ(tracker.copies(), 0);
+ EXPECT_EQ(tracker.moves(), 1);
+
+ CopyableMovableInstance t = x.get<0>();
+ EXPECT_EQ(tracker.copies(), 1);
+ EXPECT_EQ(tracker.moves(), 1);
+}
+
+TEST(CompressedTupleTest, ZeroCopyOnRefAccess) {
+ InstanceTracker tracker;
+
+ CompressedTuple<CopyableMovableInstance> x(CopyableMovableInstance(0));
+ EXPECT_EQ(tracker.copies(), 0);
+ EXPECT_EQ(tracker.moves(), 1);
+
+ CopyableMovableInstance& t1 = x.get<0>();
+ const CopyableMovableInstance& t2 = x.get<0>();
+ EXPECT_EQ(tracker.copies(), 0);
+ EXPECT_EQ(tracker.moves(), 1);
+ EXPECT_EQ(t1.value(), 0);
+ EXPECT_EQ(t2.value(), 0);
+}
+
TEST(CompressedTupleTest, Access) {
struct S {
std::string x;
@@ -173,7 +315,40 @@ TEST(CompressedTupleTest, MoveOnlyElements) {
EXPECT_EQ(*x1, 5);
}
+TEST(CompressedTupleTest, MoveConstructionMoveOnlyElements) {
+ CompressedTuple<std::unique_ptr<std::string>> base(
+ absl::make_unique<std::string>("str"));
+ EXPECT_EQ(*base.get<0>(), "str");
+
+ CompressedTuple<std::unique_ptr<std::string>> copy(std::move(base));
+ EXPECT_EQ(*copy.get<0>(), "str");
+}
+
+TEST(CompressedTupleTest, AnyElements) {
+ any a(std::string("str"));
+ CompressedTuple<any, any&> x(any(5), a);
+ EXPECT_EQ(absl::any_cast<int>(x.get<0>()), 5);
+ EXPECT_EQ(absl::any_cast<std::string>(x.get<1>()), "str");
+
+ a = 0.5f;
+ EXPECT_EQ(absl::any_cast<float>(x.get<1>()), 0.5);
+
+ // Ensure copy construction work in the face of a type with a universal
+ // implicit constructor;
+ CompressedTuple<absl::any> c{}, d(c); // NOLINT
+}
+
TEST(CompressedTupleTest, Constexpr) {
+ struct NonTrivialStruct {
+ constexpr NonTrivialStruct() = default;
+ constexpr int value() const { return v; }
+ int v = 5;
+ };
+ struct TrivialStruct {
+ TrivialStruct() = default;
+ constexpr int value() const { return v; }
+ int v;
+ };
constexpr CompressedTuple<int, double, CompressedTuple<int>, Empty<0>> x(
7, 1.25, CompressedTuple<int>(5), {});
constexpr int x0 = x.get<0>();
@@ -186,6 +361,32 @@ TEST(CompressedTupleTest, Constexpr) {
EXPECT_EQ(x2, 5);
EXPECT_EQ(x3, CallType::kConstRef);
+#if !defined(__GNUC__) || defined(__clang__) || __GNUC__ > 4
+ constexpr CompressedTuple<Empty<0>, TrivialStruct, int> trivial = {};
+ constexpr CallType trivial0 = trivial.get<0>().value();
+ constexpr int trivial1 = trivial.get<1>().value();
+ constexpr int trivial2 = trivial.get<2>();
+
+ EXPECT_EQ(trivial0, CallType::kConstRef);
+ EXPECT_EQ(trivial1, 0);
+ EXPECT_EQ(trivial2, 0);
+#endif
+
+ constexpr CompressedTuple<Empty<0>, NonTrivialStruct, absl::optional<int>>
+ non_trivial = {};
+ constexpr CallType non_trivial0 = non_trivial.get<0>().value();
+ constexpr int non_trivial1 = non_trivial.get<1>().value();
+ constexpr absl::optional<int> non_trivial2 = non_trivial.get<2>();
+
+ EXPECT_EQ(non_trivial0, CallType::kConstRef);
+ EXPECT_EQ(non_trivial1, 5);
+ EXPECT_EQ(non_trivial2, absl::nullopt);
+
+ static constexpr char data[] = "DEF";
+ constexpr CompressedTuple<const char*> z(data);
+ constexpr const char* z1 = z.get<0>();
+ EXPECT_EQ(std::string(z1), std::string(data));
+
#if defined(__clang__)
// An apparent bug in earlier versions of gcc claims these are ambiguous.
constexpr int x2m = absl::move(x.get<2>()).get<0>();
diff --git a/absl/container/internal/hashtablez_sampler.cc b/absl/container/internal/hashtablez_sampler.cc
index 6667d3ad..d03dd82e 100644
--- a/absl/container/internal/hashtablez_sampler.cc
+++ b/absl/container/internal/hashtablez_sampler.cc
@@ -32,7 +32,7 @@ constexpr int HashtablezInfo::kMaxStackDepth;
namespace {
ABSL_CONST_INIT std::atomic<bool> g_hashtablez_enabled{
- false
+ false
};
ABSL_CONST_INIT std::atomic<int32_t> g_hashtablez_sample_parameter{1 << 10};
ABSL_CONST_INIT std::atomic<int32_t> g_hashtablez_max_samples{1 << 20};
diff --git a/absl/container/internal/raw_hash_set.h b/absl/container/internal/raw_hash_set.h
index c4889cd4..656e9806 100644
--- a/absl/container/internal/raw_hash_set.h
+++ b/absl/container/internal/raw_hash_set.h
@@ -1182,7 +1182,7 @@ class raw_hash_set {
node_type extract(const_iterator position) {
auto node =
- CommonAccess::Make<node_type>(alloc_ref(), position.inner_.slot_);
+ CommonAccess::Transfer<node_type>(alloc_ref(), position.inner_.slot_);
erase_meta_only(position);
return node;
}
diff --git a/absl/container/internal/test_instance_tracker.h b/absl/container/internal/test_instance_tracker.h
index 3d4b2980..c4731dbe 100644
--- a/absl/container/internal/test_instance_tracker.h
+++ b/absl/container/internal/test_instance_tracker.h
@@ -23,7 +23,7 @@
namespace absl {
namespace test_internal {
-// A type that counts number of occurences of the type, the live occurrences of
+// A type that counts number of occurrences of the type, the live occurrences of
// the type, as well as the number of copies, moves, swaps, and comparisons that
// have occurred on the type. This is used as a base class for the copyable,
// copyable+movable, and movable types below that are used in actual tests. Use
diff --git a/absl/flags/BUILD.bazel b/absl/flags/BUILD.bazel
index 82e6ffcf..2fe61eaa 100644
--- a/absl/flags/BUILD.bazel
+++ b/absl/flags/BUILD.bazel
@@ -155,14 +155,12 @@ cc_library(
)
cc_library(
- name = "usage",
+ name = "usage_internal",
srcs = [
"internal/usage.cc",
- "usage.cc",
],
hdrs = [
"internal/usage.h",
- "usage.h",
],
copts = ABSL_DEFAULT_COPTS,
linkopts = ABSL_DEFAULT_LINKOPTS,
@@ -180,6 +178,23 @@ cc_library(
)
cc_library(
+ name = "usage",
+ srcs = [
+ "usage.cc",
+ ],
+ hdrs = [
+ "usage.h",
+ ],
+ copts = ABSL_DEFAULT_COPTS,
+ linkopts = ABSL_DEFAULT_LINKOPTS,
+ deps = [
+ ":usage_internal",
+ "//absl/strings",
+ "//absl/synchronization",
+ ],
+)
+
+cc_library(
name = "parse",
srcs = ["parse.cc"],
hdrs = [
@@ -195,6 +210,7 @@ cc_library(
":internal",
":registry",
":usage",
+ ":usage_internal",
"//absl/strings",
"//absl/synchronization",
],
@@ -360,6 +376,7 @@ cc_test(
":internal",
":parse",
":usage",
+ ":usage_internal",
"//absl/memory",
"//absl/strings",
"@com_google_googletest//:gtest",
diff --git a/absl/flags/CMakeLists.txt b/absl/flags/CMakeLists.txt
index 9c936ecc..fa1d4e17 100644
--- a/absl/flags/CMakeLists.txt
+++ b/absl/flags/CMakeLists.txt
@@ -141,13 +141,11 @@ absl_cc_library(
# Internal-only target, do not depend on directly.
absl_cc_library(
NAME
- flags_usage
+ flags_usage_internal
SRCS
"internal/usage.cc"
- "usage.cc"
HDRS
"internal/usage.h"
- "usage.h"
COPTS
${ABSL_DEFAULT_COPTS}
LINKOPTS
@@ -163,6 +161,23 @@ absl_cc_library(
absl_cc_library(
NAME
+ flags_usage
+ SRCS
+ "usage.cc"
+ HDRS
+ "usage.h"
+ COPTS
+ ${ABSL_DEFAULT_COPTS}
+ LINKOPTS
+ ${ABSL_DEFAULT_LINKOPTS}
+ DEPS
+ absl::flags_usage_internal
+ absl::strings
+ absl::synchronization
+)
+
+absl_cc_library(
+ NAME
flags_parse
SRCS
"parse.cc"
diff --git a/absl/flags/flag.cc b/absl/flags/flag.cc
index ba002edd..f16cc75e 100644
--- a/absl/flags/flag.cc
+++ b/absl/flags/flag.cc
@@ -24,24 +24,16 @@ namespace absl {
// so in debug builds we always use the slower implementation, which always
// validates the type.
#ifndef NDEBUG
-#define ABSL_FLAGS_ATOMIC_GET(T) \
- T GetFlag(const absl::Flag<T>& flag) { \
- T result; \
- flag.internal.Read(&result, &flags_internal::FlagOps<T>); \
- return result; \
- }
+#define ABSL_FLAGS_ATOMIC_GET(T) \
+ T GetFlag(const absl::Flag<T>& flag) { return flag.Get(); }
#else
-#define ABSL_FLAGS_ATOMIC_GET(T) \
- T GetFlag(const absl::Flag<T>& flag) { \
- const int64_t r = flag.internal.atomic.load(std::memory_order_acquire); \
- if (r != flags_internal::CommandLineFlag::kAtomicInit) { \
- T t; \
- memcpy(&t, &r, sizeof(T)); \
- return t; \
- } \
- T result; \
- flag.internal.Read(&result, &flags_internal::FlagOps<T>); \
- return result; \
+#define ABSL_FLAGS_ATOMIC_GET(T) \
+ T GetFlag(const absl::Flag<T>& flag) { \
+ T result; \
+ if (flag.AtomicGet(&result)) { \
+ return result; \
+ } \
+ return flag.Get(); \
}
#endif
diff --git a/absl/flags/flag.h b/absl/flags/flag.h
index 193755e5..c70023ab 100644
--- a/absl/flags/flag.h
+++ b/absl/flags/flag.h
@@ -91,30 +91,7 @@ T GetFlag(const absl::Flag<T>& flag) {
ABSL_FLAGS_INTERNAL_FOR_EACH_LOCK_FREE(ABSL_FLAGS_INTERNAL_LOCK_FREE_VALIDATE)
#undef ABSL_FLAGS_INTERNAL_LOCK_FREE_VALIDATE
- // Implementation notes:
- //
- // We are wrapping a union around the value of `T` to serve three purposes:
- //
- // 1. `U.value` has correct size and alignment for a value of type `T`
- // 2. The `U.value` constructor is not invoked since U's constructor does not
- // do it explicitly.
- // 3. The `U.value` destructor is invoked since U's destructor does it
- // explicitly. This makes `U` a kind of RAII wrapper around non default
- // constructible value of T, which is destructed when we leave the scope.
- // We do need to destroy U.value, which is constructed by
- // CommandLineFlag::Read even though we left it in a moved-from state
- // after std::move.
- //
- // All of this serves to avoid requiring `T` being default constructible.
- union U {
- T value;
- U() {}
- ~U() { value.~T(); }
- };
- U u;
-
- flag.internal.Read(&u.value, &flags_internal::FlagOps<T>);
- return std::move(u.value);
+ return flag.Get();
}
// Overload for `GetFlag()` for types that support lock-free reads.
@@ -132,7 +109,7 @@ ABSL_FLAGS_INTERNAL_FOR_EACH_LOCK_FREE(ABSL_FLAGS_INTERNAL_LOCK_FREE_EXPORT)
// but especially within performance-critical code.
template <typename T>
void SetFlag(absl::Flag<T>* flag, const T& v) {
- flag->internal.Write(&v, &flags_internal::FlagOps<T>);
+ flag->Set(v);
}
// Overload of `SetFlag()` to allow callers to pass in a value that is
@@ -141,7 +118,7 @@ void SetFlag(absl::Flag<T>* flag, const T& v) {
template <typename T, typename V>
void SetFlag(absl::Flag<T>* flag, const V& v) {
T value(v);
- SetFlag<T>(flag, value);
+ flag->Set(value);
}
} // namespace absl
@@ -239,17 +216,17 @@ void SetFlag(absl::Flag<T>* flag, const V& v) {
// Note: Name of registrar object is not arbitrary. It is used to "grab"
// global name for FLAGS_no<flag_name> symbol, thus preventing the possibility
// of defining two flags with names foo and nofoo.
-#define ABSL_FLAG_IMPL(Type, name, default_value, help) \
- namespace absl {} \
- ABSL_FLAG_IMPL_DECLARE_DEF_VAL_WRAPPER(name, Type, default_value) \
- ABSL_FLAG_IMPL_DECLARE_HELP_WRAPPER(name, help) \
- absl::Flag<Type> FLAGS_##name( \
- ABSL_FLAG_IMPL_FLAGNAME(#name), \
- &AbslFlagsWrapHelp##name, \
- ABSL_FLAG_IMPL_FILENAME(), \
- &absl::flags_internal::FlagMarshallingOps<Type>, \
- &AbslFlagsInitFlag##name); \
- extern bool FLAGS_no##name; \
+#define ABSL_FLAG_IMPL(Type, name, default_value, help) \
+ namespace absl {} \
+ ABSL_FLAG_IMPL_DECLARE_DEF_VAL_WRAPPER(name, Type, default_value) \
+ ABSL_FLAG_IMPL_DECLARE_HELP_WRAPPER(name, help) \
+ absl::Flag<Type> FLAGS_##name( \
+ ABSL_FLAG_IMPL_FLAGNAME(#name), \
+ &AbslFlagsWrapHelp##name, \
+ ABSL_FLAG_IMPL_FILENAME(), \
+ &absl::flags_internal::FlagMarshallingOps<Type>, \
+ &AbslFlagsInitFlag##name); \
+ extern bool FLAGS_no##name; \
bool FLAGS_no##name = ABSL_FLAG_IMPL_REGISTRAR(Type, FLAGS_##name)
// ABSL_RETIRED_FLAG
diff --git a/absl/flags/internal/commandlineflag.cc b/absl/flags/internal/commandlineflag.cc
index 74444721..98a46695 100644
--- a/absl/flags/internal/commandlineflag.cc
+++ b/absl/flags/internal/commandlineflag.cc
@@ -37,44 +37,6 @@ const char kStrippedFlagHelp[] = "\001\002\003\004 (unknown) \004\003\002\001";
namespace {
-void StoreAtomic(CommandLineFlag* flag, const void* data, size_t size) {
- int64_t t = 0;
- assert(size <= sizeof(int64_t));
- memcpy(&t, data, size);
- flag->atomic.store(t, std::memory_order_release);
-}
-
-// If the flag has a mutation callback this function invokes it. While the
-// callback is being invoked the primary flag's mutex is unlocked and it is
-// re-locked back after call to callback is completed. Callback invocation is
-// guarded by flag's secondary mutex instead which prevents concurrent callback
-// invocation. Note that it is possible for other thread to grab the primary
-// lock and update flag's value at any time during the callback invocation.
-// This is by design. Callback can get a value of the flag if necessary, but it
-// might be different from the value initiated the callback and it also can be
-// different by the time the callback invocation is completed.
-// Requires that *primary_lock be held in exclusive mode; it may be released
-// and reacquired by the implementation.
-void InvokeCallback(CommandLineFlag* flag, absl::Mutex* primary_lock)
- EXCLUSIVE_LOCKS_REQUIRED(primary_lock) {
- if (!flag->callback) return;
-
- // The callback lock is guaranteed initialized, because *primary_lock exists.
- absl::Mutex* callback_mu = &flag->locks->callback_mu;
-
- // When executing the callback we need the primary flag's mutex to be unlocked
- // so that callback can retrieve the flag's value.
- primary_lock->Unlock();
-
- {
- absl::MutexLock lock(callback_mu);
-
- flag->callback();
- }
-
- primary_lock->Lock();
-}
-
// Currently we only validate flag values for user-defined flag types.
bool ShouldValidateFlagValue(const CommandLineFlag& flag) {
#define DONT_VALIDATE(T) \
@@ -89,145 +51,72 @@ bool ShouldValidateFlagValue(const CommandLineFlag& flag) {
} // namespace
-// Update any copy of the flag value that is stored in an atomic word.
-// In addition if flag has a mutation callback this function invokes it.
-void UpdateCopy(CommandLineFlag* flag, absl::Mutex* primary_lock)
- EXCLUSIVE_LOCKS_REQUIRED(primary_lock) {
-#define STORE_ATOMIC(T) \
- else if (flag->IsOfType<T>()) { \
- StoreAtomic(flag, flag->cur, sizeof(T)); \
- }
-
- if (false) {
- }
- ABSL_FLAGS_INTERNAL_FOR_EACH_LOCK_FREE(STORE_ATOMIC)
-#undef STORE_ATOMIC
+absl::Mutex* InitFlag(CommandLineFlag* flag) {
+ ABSL_CONST_INIT static absl::Mutex init_lock(absl::kConstInit);
+ absl::Mutex* mu;
- InvokeCallback(flag, primary_lock);
-}
+ {
+ absl::MutexLock lock(&init_lock);
-// Ensure that the lazily initialized fields of *flag have been initialized,
-// and return &flag->locks->primary_mu.
-absl::Mutex* InitFlagIfNecessary(CommandLineFlag* flag)
- LOCK_RETURNED(flag->locks->primary_mu) {
- absl::Mutex* mu;
- if (!flag->inited.load(std::memory_order_acquire)) {
- // Need to initialize lazily initialized fields.
- ABSL_CONST_INIT static absl::Mutex init_lock(absl::kConstInit);
- init_lock.Lock();
if (flag->locks == nullptr) { // Must initialize Mutexes for this flag.
flag->locks = new flags_internal::CommandLineFlagLocks;
}
+
mu = &flag->locks->primary_mu;
- init_lock.Unlock();
- mu->Lock();
- if (!flag->retired &&
- flag->def == nullptr) { // Need to initialize def and cur fields.
+ }
+
+ {
+ absl::MutexLock lock(mu);
+
+ if (!flag->retired && flag->def == nullptr) {
+ // Need to initialize def and cur fields.
flag->def = (*flag->make_init_value)();
flag->cur = Clone(flag->op, flag->def);
- UpdateCopy(flag, mu);
+ UpdateCopy(flag);
+ flag->inited.store(true, std::memory_order_release);
+ flag->InvokeCallback();
}
- mu->Unlock();
- flag->inited.store(true, std::memory_order_release);
- } else { // All fields initialized; flag->locks is therefore safe to read.
- mu = &flag->locks->primary_mu;
}
+
+ flag->inited.store(true, std::memory_order_release);
return mu;
}
-// Return true iff flag value was changed via direct-access.
-bool ChangedDirectly(CommandLineFlag* flag, const void* a, const void* b) {
- if (!flag->IsAbseilFlag()) {
- // Need to compare values for direct-access flags.
-#define CHANGED_FOR_TYPE(T) \
- if (flag->IsOfType<T>()) { \
- return *reinterpret_cast<const T*>(a) != *reinterpret_cast<const T*>(b); \
+// Ensure that the lazily initialized fields of *flag have been initialized,
+// and return &flag->locks->primary_mu.
+absl::Mutex* CommandLineFlag::InitFlagIfNecessary() const
+ LOCK_RETURNED(locks->primary_mu) {
+ if (!this->inited.load(std::memory_order_acquire)) {
+ return InitFlag(const_cast<CommandLineFlag*>(this));
}
- CHANGED_FOR_TYPE(bool);
- CHANGED_FOR_TYPE(int32_t);
- CHANGED_FOR_TYPE(int64_t);
- CHANGED_FOR_TYPE(uint64_t);
- CHANGED_FOR_TYPE(double);
- CHANGED_FOR_TYPE(std::string);
-#undef CHANGED_FOR_TYPE
- }
- return false;
+ // All fields initialized; this->locks is therefore safe to read.
+ return &this->locks->primary_mu;
}
-// Direct-access flags can be modified without going through the
-// flag API. Detect such changes and updated the modified bit.
-void UpdateModifiedBit(CommandLineFlag* flag) {
- if (!flag->IsAbseilFlag()) {
- absl::MutexLock l(InitFlagIfNecessary(flag));
- if (!flag->modified && ChangedDirectly(flag, flag->cur, flag->def)) {
- flag->modified = true;
- }
+void CommandLineFlag::Destroy() const {
+ // Values are heap allocated for retired and Abseil Flags.
+ if (IsRetired() || IsAbseilFlag()) {
+ if (this->cur) Delete(this->op, this->cur);
+ if (this->def) Delete(this->op, this->def);
}
-}
-bool Validate(CommandLineFlag*, const void*) {
- return true;
+ delete this->locks;
}
-std::string HelpText::GetHelpText() const {
- if (help_function_) return help_function_();
- if (help_message_) return help_message_;
-
- return {};
+bool CommandLineFlag::IsModified() const {
+ absl::MutexLock l(InitFlagIfNecessary());
+ return modified;
}
-const int64_t CommandLineFlag::kAtomicInit;
-
-void CommandLineFlag::Read(void* dst,
- const flags_internal::FlagOpFn dst_op) const {
- absl::ReaderMutexLock l(
- InitFlagIfNecessary(const_cast<CommandLineFlag*>(this)));
-
- // `dst_op` is the unmarshaling operation corresponding to the declaration
- // visibile at the call site. `op` is the Flag's defined unmarshalling
- // operation. They must match for this operation to be well-defined.
- if (ABSL_PREDICT_FALSE(dst_op != op)) {
- ABSL_INTERNAL_LOG(
- ERROR,
- absl::StrCat("Flag '", name,
- "' is defined as one type and declared as another"));
- }
- CopyConstruct(op, cur, dst);
+void CommandLineFlag::SetModified(bool is_modified) {
+ absl::MutexLock l(InitFlagIfNecessary());
+ modified = is_modified;
}
-void CommandLineFlag::Write(const void* src,
- const flags_internal::FlagOpFn src_op) {
- absl::Mutex* mu = InitFlagIfNecessary(this);
- absl::MutexLock l(mu);
-
- // `src_op` is the marshalling operation corresponding to the declaration
- // visible at the call site. `op` is the Flag's defined marshalling operation.
- // They must match for this operation to be well-defined.
- if (ABSL_PREDICT_FALSE(src_op != op)) {
- ABSL_INTERNAL_LOG(
- ERROR,
- absl::StrCat("Flag '", name,
- "' is defined as one type and declared as another"));
- }
-
- if (ShouldValidateFlagValue(*this)) {
- void* obj = Clone(op, src);
- std::string ignored_error;
- std::string src_as_str = Unparse(marshalling_op, src);
- if (!Parse(marshalling_op, src_as_str, obj, &ignored_error) ||
- !Validate(this, obj)) {
- ABSL_INTERNAL_LOG(ERROR, absl::StrCat("Attempt to set flag '", name,
- "' to invalid value ", src_as_str));
- }
- Delete(op, obj);
- }
-
- modified = true;
- counter++;
- Copy(op, src, cur);
-
- UpdateCopy(this, mu);
+bool CommandLineFlag::IsSpecifiedOnCommandLine() const {
+ absl::MutexLock l(InitFlagIfNecessary());
+ return on_command_line;
}
absl::string_view CommandLineFlag::Typename() const {
@@ -259,21 +148,96 @@ std::string CommandLineFlag::Filename() const {
}
std::string CommandLineFlag::DefaultValue() const {
+ absl::MutexLock l(InitFlagIfNecessary());
+
return Unparse(this->marshalling_op, this->def);
}
std::string CommandLineFlag::CurrentValue() const {
+ absl::MutexLock l(InitFlagIfNecessary());
+
return Unparse(this->marshalling_op, this->cur);
}
+bool CommandLineFlag::HasValidatorFn() const {
+ absl::MutexLock l(InitFlagIfNecessary());
+
+ return this->validator != nullptr;
+}
+
+bool CommandLineFlag::SetValidatorFn(FlagValidator fn) {
+ absl::MutexLock l(InitFlagIfNecessary());
+
+ // ok to register the same function over and over again
+ if (fn == this->validator) return true;
+
+ // Can't set validator to a different function, unless reset first.
+ if (fn != nullptr && this->validator != nullptr) {
+ ABSL_INTERNAL_LOG(
+ WARNING, absl::StrCat("Ignoring SetValidatorFn() for flag '", Name(),
+ "': validate-fn already registered"));
+
+ return false;
+ }
+
+ this->validator = fn;
+ return true;
+}
+
+bool CommandLineFlag::InvokeValidator(const void* value) const
+ EXCLUSIVE_LOCKS_REQUIRED(this->locks->primary_mu) {
+ if (!this->validator) {
+ return true;
+ }
+
+ (void)value;
+
+ ABSL_INTERNAL_LOG(
+ FATAL,
+ absl::StrCat("Flag '", Name(),
+ "' of encapsulated type should not have a validator"));
+
+ return false;
+}
+
void CommandLineFlag::SetCallback(
const flags_internal::FlagCallback mutation_callback) {
- absl::Mutex* mu = InitFlagIfNecessary(this);
- absl::MutexLock l(mu);
+ absl::MutexLock l(InitFlagIfNecessary());
callback = mutation_callback;
- InvokeCallback(this, mu);
+ InvokeCallback();
+}
+
+// If the flag has a mutation callback this function invokes it. While the
+// callback is being invoked the primary flag's mutex is unlocked and it is
+// re-locked back after call to callback is completed. Callback invocation is
+// guarded by flag's secondary mutex instead which prevents concurrent callback
+// invocation. Note that it is possible for other thread to grab the primary
+// lock and update flag's value at any time during the callback invocation.
+// This is by design. Callback can get a value of the flag if necessary, but it
+// might be different from the value initiated the callback and it also can be
+// different by the time the callback invocation is completed.
+// Requires that *primary_lock be held in exclusive mode; it may be released
+// and reacquired by the implementation.
+void CommandLineFlag::InvokeCallback()
+ EXCLUSIVE_LOCKS_REQUIRED(this->locks->primary_mu) {
+ if (!this->callback) return;
+
+ // The callback lock is guaranteed initialized, because *locks->primary_mu
+ // exists.
+ absl::Mutex* callback_mu = &this->locks->callback_mu;
+
+ // When executing the callback we need the primary flag's mutex to be unlocked
+ // so that callback can retrieve the flag's value.
+ this->locks->primary_mu.Unlock();
+
+ {
+ absl::MutexLock lock(callback_mu);
+ this->callback();
+ }
+
+ this->locks->primary_mu.Lock();
}
// Attempts to parse supplied `value` string using parsing routine in the `flag`
@@ -282,8 +246,9 @@ void CommandLineFlag::SetCallback(
// parsed value in 'dst' assuming it is a pointer to the flag's value type. In
// case if any error is encountered in either step, the error message is stored
// in 'err'
-static bool TryParseLocked(CommandLineFlag* flag, void* dst,
- absl::string_view value, std::string* err) {
+bool TryParseLocked(CommandLineFlag* flag, void* dst, absl::string_view value,
+ std::string* err)
+ EXCLUSIVE_LOCKS_REQUIRED(flag->locks->primary_mu) {
void* tentative_value = Clone(flag->op, flag->def);
std::string parse_err;
if (!Parse(flag->marshalling_op, value, tentative_value, &parse_err)) {
@@ -297,7 +262,7 @@ static bool TryParseLocked(CommandLineFlag* flag, void* dst,
return false;
}
- if (!Validate(flag, tentative_value)) {
+ if (!flag->InvokeValidator(tentative_value)) {
*err = absl::StrCat("Failed validation of new value '",
Unparse(flag->marshalling_op, tentative_value),
"' for flag '", flag->Name(), "'");
@@ -324,17 +289,23 @@ bool CommandLineFlag::SetFromString(absl::string_view value,
ValueSource source, std::string* err) {
if (IsRetired()) return false;
- UpdateModifiedBit(this);
+ absl::MutexLock l(InitFlagIfNecessary());
- absl::Mutex* mu = InitFlagIfNecessary(this);
- absl::MutexLock l(mu);
+ // Direct-access flags can be modified without going through the
+ // flag API. Detect such changes and update the flag->modified bit.
+ if (!IsAbseilFlag()) {
+ if (!this->modified && ChangedDirectly(this, this->cur, this->def)) {
+ this->modified = true;
+ }
+ }
switch (set_mode) {
case SET_FLAGS_VALUE: {
// set or modify the flag's value
if (!TryParseLocked(this, this->cur, value, err)) return false;
this->modified = true;
- UpdateCopy(this, mu);
+ UpdateCopy(this);
+ InvokeCallback();
if (source == kCommandLine) {
this->on_command_line = true;
@@ -346,7 +317,8 @@ bool CommandLineFlag::SetFromString(absl::string_view value,
if (!this->modified) {
if (!TryParseLocked(this, this->cur, value, err)) return false;
this->modified = true;
- UpdateCopy(this, mu);
+ UpdateCopy(this);
+ InvokeCallback();
} else {
// TODO(rogeeff): review and fix this semantic. Currently we do not fail
// in this case if flag is modified. This is misleading since the flag's
@@ -365,7 +337,8 @@ bool CommandLineFlag::SetFromString(absl::string_view value,
if (!this->modified) {
// Need to set both defvalue *and* current, in this case
Copy(this->op, this->def, this->cur);
- UpdateCopy(this, mu);
+ UpdateCopy(this);
+ InvokeCallback();
}
break;
}
@@ -379,5 +352,143 @@ bool CommandLineFlag::SetFromString(absl::string_view value,
return true;
}
+void CommandLineFlag::StoreAtomic(size_t size) {
+ int64_t t = 0;
+ assert(size <= sizeof(int64_t));
+ memcpy(&t, this->cur, size);
+ this->atomic.store(t, std::memory_order_release);
+}
+
+void CommandLineFlag::CheckDefaultValueParsingRoundtrip() const {
+ std::string v = DefaultValue();
+
+ absl::MutexLock lock(InitFlagIfNecessary());
+
+ void* dst = Clone(this->op, this->def);
+ std::string error;
+ if (!flags_internal::Parse(this->marshalling_op, v, dst, &error)) {
+ ABSL_INTERNAL_LOG(
+ FATAL,
+ absl::StrCat("Flag ", Name(), " (from ", Filename(),
+ "): std::string form of default value '", v,
+ "' could not be parsed; error=", error));
+ }
+
+ // We do not compare dst to def since parsing/unparsing may make
+ // small changes, e.g., precision loss for floating point types.
+ Delete(this->op, dst);
+}
+
+bool CommandLineFlag::ValidateDefaultValue() const {
+ absl::MutexLock lock(InitFlagIfNecessary());
+ return InvokeValidator(this->def);
+}
+
+bool CommandLineFlag::ValidateInputValue(absl::string_view value) const {
+ absl::MutexLock l(InitFlagIfNecessary()); // protect default value access
+
+ void* obj = Clone(this->op, this->def);
+ std::string ignored_error;
+ const bool result =
+ flags_internal::Parse(this->marshalling_op, value, obj, &ignored_error) &&
+ InvokeValidator(obj);
+ Delete(this->op, obj);
+ return result;
+}
+
+const int64_t CommandLineFlag::kAtomicInit;
+
+void CommandLineFlag::Read(void* dst,
+ const flags_internal::FlagOpFn dst_op) const {
+ absl::ReaderMutexLock l(InitFlagIfNecessary());
+
+ // `dst_op` is the unmarshaling operation corresponding to the declaration
+ // visibile at the call site. `op` is the Flag's defined unmarshalling
+ // operation. They must match for this operation to be well-defined.
+ if (ABSL_PREDICT_FALSE(dst_op != op)) {
+ ABSL_INTERNAL_LOG(
+ ERROR,
+ absl::StrCat("Flag '", name,
+ "' is defined as one type and declared as another"));
+ }
+ CopyConstruct(op, cur, dst);
+}
+
+void CommandLineFlag::Write(const void* src,
+ const flags_internal::FlagOpFn src_op) {
+ absl::MutexLock l(InitFlagIfNecessary());
+
+ // `src_op` is the marshalling operation corresponding to the declaration
+ // visible at the call site. `op` is the Flag's defined marshalling operation.
+ // They must match for this operation to be well-defined.
+ if (ABSL_PREDICT_FALSE(src_op != op)) {
+ ABSL_INTERNAL_LOG(
+ ERROR,
+ absl::StrCat("Flag '", name,
+ "' is defined as one type and declared as another"));
+ }
+
+ if (ShouldValidateFlagValue(*this)) {
+ void* obj = Clone(op, src);
+ std::string ignored_error;
+ std::string src_as_str = Unparse(marshalling_op, src);
+ if (!Parse(marshalling_op, src_as_str, obj, &ignored_error) ||
+ !InvokeValidator(obj)) {
+ ABSL_INTERNAL_LOG(ERROR, absl::StrCat("Attempt to set flag '", name,
+ "' to invalid value ", src_as_str));
+ }
+ Delete(op, obj);
+ }
+
+ modified = true;
+ counter++;
+ Copy(op, src, cur);
+
+ UpdateCopy(this);
+ InvokeCallback();
+}
+
+std::string HelpText::GetHelpText() const {
+ if (help_function_) return help_function_();
+ if (help_message_) return help_message_;
+
+ return {};
+}
+
+// Update any copy of the flag value that is stored in an atomic word.
+// In addition if flag has a mutation callback this function invokes it.
+void UpdateCopy(CommandLineFlag* flag) {
+#define STORE_ATOMIC(T) \
+ else if (flag->IsOfType<T>()) { \
+ flag->StoreAtomic(sizeof(T)); \
+ }
+
+ if (false) {
+ }
+ ABSL_FLAGS_INTERNAL_FOR_EACH_LOCK_FREE(STORE_ATOMIC)
+#undef STORE_ATOMIC
+}
+
+// Return true iff flag value was changed via direct-access.
+bool ChangedDirectly(CommandLineFlag* flag, const void* a, const void* b) {
+ if (!flag->IsAbseilFlag()) {
+// Need to compare values for direct-access flags.
+#define CHANGED_FOR_TYPE(T) \
+ if (flag->IsOfType<T>()) { \
+ return *reinterpret_cast<const T*>(a) != *reinterpret_cast<const T*>(b); \
+ }
+
+ CHANGED_FOR_TYPE(bool);
+ CHANGED_FOR_TYPE(int32_t);
+ CHANGED_FOR_TYPE(int64_t);
+ CHANGED_FOR_TYPE(uint64_t);
+ CHANGED_FOR_TYPE(double);
+ CHANGED_FOR_TYPE(std::string);
+#undef CHANGED_FOR_TYPE
+ }
+
+ return false;
+}
+
} // namespace flags_internal
} // namespace absl
diff --git a/absl/flags/internal/commandlineflag.h b/absl/flags/internal/commandlineflag.h
index 4815cdc7..d82443a7 100644
--- a/absl/flags/internal/commandlineflag.h
+++ b/absl/flags/internal/commandlineflag.h
@@ -69,11 +69,15 @@ using HelpGenFunc = std::string (*)();
// based on default value supplied in flag's definition)
using InitialValGenFunc = void* (*)();
+struct CommandLineFlagInfo;
+
// Signature for the mutation callback used by watched Flags
// The callback is noexcept.
// TODO(rogeeff): add noexcept after C++17 support is added.
using FlagCallback = void (*)();
+using FlagValidator = bool (*)();
+
extern const char kStrippedFlagHelp[];
// The per-type function
@@ -217,6 +221,9 @@ struct CommandLineFlag {
atomic(kAtomicInit),
locks(nullptr) {}
+ // Revert the init routine.
+ void Destroy() const;
+
// Not copyable/assignable.
CommandLineFlag(const CommandLineFlag&) = delete;
CommandLineFlag& operator=(const CommandLineFlag&) = delete;
@@ -224,7 +231,9 @@ struct CommandLineFlag {
absl::string_view Name() const { return name; }
std::string Help() const { return help.GetHelpText(); }
bool IsRetired() const { return this->retired; }
- bool IsSpecifiedOnCommandLine() const { return on_command_line; }
+ bool IsModified() const;
+ void SetModified(bool is_modified);
+ bool IsSpecifiedOnCommandLine() const;
// Returns true iff this is a handle to an Abseil Flag.
bool IsAbseilFlag() const {
// Set to null for V1 flags
@@ -236,6 +245,10 @@ struct CommandLineFlag {
std::string DefaultValue() const;
std::string CurrentValue() const;
+ bool HasValidatorFn() const;
+ bool SetValidatorFn(FlagValidator fn);
+ bool InvokeValidator(const void* value) const;
+
// Return true iff flag has type T.
template <typename T>
inline bool IsOfType() const {
@@ -245,7 +258,7 @@ struct CommandLineFlag {
// Attempts to retrieve the flag value. Returns value on success,
// absl::nullopt otherwise.
template <typename T>
- absl::optional<T> Get() {
+ absl::optional<T> Get() const {
if (IsRetired() || flags_internal::FlagOps<T> != this->op)
return absl::nullopt;
@@ -256,6 +269,7 @@ struct CommandLineFlag {
}
void SetCallback(const flags_internal::FlagCallback mutation_callback);
+ void InvokeCallback();
// Sets the value of the flag based on specified std::string `value`. If the flag
// was successfully set to new value, it returns true. Otherwise, sets `error`
@@ -269,27 +283,35 @@ struct CommandLineFlag {
flags_internal::FlagSettingMode set_mode,
flags_internal::ValueSource source, std::string* error);
+ void StoreAtomic(size_t size);
+
+ void CheckDefaultValueParsingRoundtrip() const;
+ // Invoke the flag validators for old flags.
+ // TODO(rogeeff): implement proper validators for Abseil Flags
+ bool ValidateDefaultValue() const;
+ bool ValidateInputValue(absl::string_view value) const;
+
// Constant configuration for a particular flag.
private:
const char* const name;
const HelpText help;
const char* const filename;
- public:
- const FlagOpFn op; // Type-specific handler
+ protected:
+ const FlagOpFn op; // Type-specific handler
const FlagMarshallingOpFn marshalling_op; // Marshalling ops handler
const InitialValGenFunc make_init_value; // Makes initial value for the flag
- const bool retired; // Is the flag retired?
- std::atomic<bool> inited; // fields have been lazily initialized
+ const bool retired; // Is the flag retired?
+ std::atomic<bool> inited; // fields have been lazily initialized
// Mutable state (guarded by locks->primary_mu).
- bool modified; // Has flag value been modified?
- bool on_command_line; // Specified on command line.
- bool (*validator)(); // Validator function, or nullptr
- FlagCallback callback; // Mutation callback, or nullptr
- void* def; // Lazily initialized pointer to default value
- void* cur; // Lazily initialized pointer to current value
- int64_t counter; // Mutation counter
+ bool modified; // Has flag value been modified?
+ bool on_command_line; // Specified on command line.
+ FlagValidator validator; // Validator function, or nullptr
+ FlagCallback callback; // Mutation callback, or nullptr
+ void* def; // Lazily initialized pointer to default value
+ void* cur; // Lazily initialized pointer to current value
+ int64_t counter; // Mutation counter
// For some types, a copy of the current value is kept in an atomically
// accessible field.
@@ -302,24 +324,26 @@ struct CommandLineFlag {
// TODO(rogeeff): fix it once Mutex has constexpr constructor
struct CommandLineFlagLocks* locks; // locks, laziliy allocated.
+ // Ensure that the lazily initialized fields of *flag have been initialized,
+ // and return the lock which should be locked when flag's state is mutated.
+ absl::Mutex* InitFlagIfNecessary() const;
+
// copy construct new value of flag's type in a memory referenced by dst
// based on current flag's value
void Read(void* dst, const flags_internal::FlagOpFn dst_op) const;
// updates flag's value to *src (locked)
void Write(const void* src, const flags_internal::FlagOpFn src_op);
- ABSL_DEPRECATED(
- "temporary until FlagName call sites are migrated and validator API is "
- "changed")
- const char* NameAsCString() const { return name; }
-
- private:
friend class FlagRegistry;
+ friend class FlagPtrMap;
+ friend class FlagSaverImpl;
+ friend void FillCommandLineFlagInfo(CommandLineFlag* flag,
+ CommandLineFlagInfo* result);
+ friend bool TryParseLocked(CommandLineFlag* flag, void* dst,
+ absl::string_view value, std::string* err);
+ friend absl::Mutex* InitFlag(CommandLineFlag* flag);
};
-// Ensure that the lazily initialized fields of *flag have been initialized,
-// and return &flag->locks->primary_mu.
-absl::Mutex* InitFlagIfNecessary(CommandLineFlag* flag);
// Update any copy of the flag value that is stored in an atomic word.
// In addition if flag has a mutation callback this function invokes it. While
// callback is being invoked the primary flag's mutex is unlocked and it is
@@ -332,15 +356,9 @@ absl::Mutex* InitFlagIfNecessary(CommandLineFlag* flag);
// different by the time the callback invocation is completed.
// Requires that *primary_lock be held in exclusive mode; it may be released
// and reacquired by the implementation.
-void UpdateCopy(CommandLineFlag* flag, absl::Mutex* primary_lock);
+void UpdateCopy(CommandLineFlag* flag);
// Return true iff flag value was changed via direct-access.
bool ChangedDirectly(CommandLineFlag* flag, const void* a, const void* b);
-// Direct-access flags can be modified without going through the
-// flag API. Detect such changes and updated the modified bit.
-void UpdateModifiedBit(CommandLineFlag* flag);
-// Invoke the flag validators for old flags.
-// TODO(rogeeff): implement proper validators for Abseil Flags
-bool Validate(CommandLineFlag* flag, const void* value);
// This macro is the "source of truth" for the list of supported flag types we
// expect to perform lock free operations on. Specifically it generates code,
diff --git a/absl/flags/internal/commandlineflag_test.cc b/absl/flags/internal/commandlineflag_test.cc
index 705f301c..f0d57adb 100644
--- a/absl/flags/internal/commandlineflag_test.cc
+++ b/absl/flags/internal/commandlineflag_test.cc
@@ -100,39 +100,39 @@ TEST_F(CommandLineFlagTest, TestSetFromStringCurrentValue) {
std::string err;
auto* flag_01 = flags::FindCommandLineFlag("int_flag");
- EXPECT_FALSE(flag_01->on_command_line);
+ EXPECT_FALSE(flag_01->IsSpecifiedOnCommandLine());
EXPECT_TRUE(flag_01->SetFromString("11", flags::SET_FLAGS_VALUE,
flags::kProgrammaticChange, &err));
EXPECT_EQ(absl::GetFlag(FLAGS_int_flag), 11);
- EXPECT_FALSE(flag_01->on_command_line);
+ EXPECT_FALSE(flag_01->IsSpecifiedOnCommandLine());
EXPECT_TRUE(flag_01->SetFromString("-123", flags::SET_FLAGS_VALUE,
flags::kProgrammaticChange, &err));
EXPECT_EQ(absl::GetFlag(FLAGS_int_flag), -123);
- EXPECT_FALSE(flag_01->on_command_line);
+ EXPECT_FALSE(flag_01->IsSpecifiedOnCommandLine());
EXPECT_TRUE(!flag_01->SetFromString("xyz", flags::SET_FLAGS_VALUE,
flags::kProgrammaticChange, &err));
EXPECT_EQ(absl::GetFlag(FLAGS_int_flag), -123);
EXPECT_EQ(err, "Illegal value 'xyz' specified for flag 'int_flag'");
- EXPECT_FALSE(flag_01->on_command_line);
+ EXPECT_FALSE(flag_01->IsSpecifiedOnCommandLine());
EXPECT_TRUE(!flag_01->SetFromString("A1", flags::SET_FLAGS_VALUE,
flags::kProgrammaticChange, &err));
EXPECT_EQ(absl::GetFlag(FLAGS_int_flag), -123);
EXPECT_EQ(err, "Illegal value 'A1' specified for flag 'int_flag'");
- EXPECT_FALSE(flag_01->on_command_line);
+ EXPECT_FALSE(flag_01->IsSpecifiedOnCommandLine());
EXPECT_TRUE(flag_01->SetFromString("0x10", flags::SET_FLAGS_VALUE,
flags::kProgrammaticChange, &err));
EXPECT_EQ(absl::GetFlag(FLAGS_int_flag), 16);
- EXPECT_FALSE(flag_01->on_command_line);
+ EXPECT_FALSE(flag_01->IsSpecifiedOnCommandLine());
EXPECT_TRUE(flag_01->SetFromString("011", flags::SET_FLAGS_VALUE,
flags::kCommandLine, &err));
EXPECT_EQ(absl::GetFlag(FLAGS_int_flag), 11);
- EXPECT_TRUE(flag_01->on_command_line);
+ EXPECT_TRUE(flag_01->IsSpecifiedOnCommandLine());
EXPECT_TRUE(!flag_01->SetFromString("", flags::SET_FLAGS_VALUE,
flags::kProgrammaticChange, &err));
diff --git a/absl/flags/internal/flag.h b/absl/flags/internal/flag.h
index 9b32f467..bc50de54 100644
--- a/absl/flags/internal/flag.h
+++ b/absl/flags/internal/flag.h
@@ -24,40 +24,58 @@ namespace flags_internal {
// This is "unspecified" implementation of absl::Flag<T> type.
template <typename T>
-class Flag {
+class Flag : public flags_internal::CommandLineFlag {
public:
constexpr Flag(const char* name, const flags_internal::HelpGenFunc help_gen,
const char* filename,
- const flags_internal::FlagMarshallingOpFn marshalling_op,
+ const flags_internal::FlagMarshallingOpFn marshalling_op_arg,
const flags_internal::InitialValGenFunc initial_value_gen)
- : internal(name, flags_internal::HelpText::FromFunctionPointer(help_gen),
- filename, &flags_internal::FlagOps<T>, marshalling_op,
- initial_value_gen,
- /*retired_arg=*/false, /*def_arg=*/nullptr,
- /*cur_arg=*/nullptr) {}
-
- // Not copyable/assignable.
- Flag(const Flag<T>&) = delete;
- Flag<T>& operator=(const Flag<T>&) = delete;
-
- absl::string_view Name() const { return internal.Name(); }
- std::string Help() const { return internal.Help(); }
- std::string Filename() const { return internal.Filename(); }
+ : flags_internal::CommandLineFlag(
+ name, flags_internal::HelpText::FromFunctionPointer(help_gen),
+ filename, &flags_internal::FlagOps<T>, marshalling_op_arg,
+ initial_value_gen,
+ /*retired_arg=*/false, /*def_arg=*/nullptr,
+ /*cur_arg=*/nullptr) {}
+
+ T Get() const {
+ // Implementation notes:
+ //
+ // We are wrapping a union around the value of `T` to serve three purposes:
+ //
+ // 1. `U.value` has correct size and alignment for a value of type `T`
+ // 2. The `U.value` constructor is not invoked since U's constructor does
+ // not
+ // do it explicitly.
+ // 3. The `U.value` destructor is invoked since U's destructor does it
+ // explicitly. This makes `U` a kind of RAII wrapper around non default
+ // constructible value of T, which is destructed when we leave the
+ // scope. We do need to destroy U.value, which is constructed by
+ // CommandLineFlag::Read even though we left it in a moved-from state
+ // after std::move.
+ //
+ // All of this serves to avoid requiring `T` being default constructible.
+ union U {
+ T value;
+ U() {}
+ ~U() { value.~T(); }
+ };
+ U u;
+
+ this->Read(&u.value, &flags_internal::FlagOps<T>);
+ return std::move(u.value);
+ }
- absl::flags_internal::CommandLineFlag internal;
+ bool AtomicGet(T* v) const {
+ const int64_t r = this->atomic.load(std::memory_order_acquire);
+ if (r != flags_internal::CommandLineFlag::kAtomicInit) {
+ memcpy(v, &r, sizeof(T));
+ return true;
+ }
- void SetCallback(const flags_internal::FlagCallback mutation_callback) {
- internal.SetCallback(mutation_callback);
+ return false;
}
- private:
- // TODO(rogeeff): add these validations once UnparseFlag invocation is fixed
- // for built-in types and when we cleanup existing code from operating on
- // forward declared types.
- // auto IsCopyConstructible(const T& v) -> decltype(T(v));
- // auto HasAbslParseFlag(absl::string_view in, T* dst, std::string* err)
- // -> decltype(AbslParseFlag(in, dst, err));
- // auto HasAbslUnparseFlag(const T& v) -> decltype(AbslUnparseFlag(v));
+ void Set(const T& v) { this->Write(&v, &flags_internal::FlagOps<T>); }
};
// This class facilitates Flag object registration and tail expression-based
@@ -67,7 +85,7 @@ template <typename T, bool do_register>
class FlagRegistrar {
public:
explicit FlagRegistrar(Flag<T>* flag) : flag_(flag) {
- if (do_register) flags_internal::RegisterCommandLineFlag(&flag_->internal);
+ if (do_register) flags_internal::RegisterCommandLineFlag(flag_);
}
FlagRegistrar& OnUpdate(flags_internal::FlagCallback cb) && {
diff --git a/absl/flags/internal/registry.cc b/absl/flags/internal/registry.cc
index e52cbb68..f37871c9 100644
--- a/absl/flags/internal/registry.cc
+++ b/absl/flags/internal/registry.cc
@@ -34,13 +34,7 @@ namespace flags_internal {
namespace {
void DestroyFlag(CommandLineFlag* flag) NO_THREAD_SAFETY_ANALYSIS {
- // Values are heap allocated for retired and Abseil Flags.
- if (flag->IsRetired() || flag->IsAbseilFlag()) {
- if (flag->cur) Delete(flag->op, flag->cur);
- if (flag->def) Delete(flag->op, flag->def);
- }
-
- delete flag->locks;
+ flag->Destroy();
// CommandLineFlag handle object is heap allocated for non Abseil Flags.
if (!flag->IsAbseilFlag()) {
@@ -48,6 +42,8 @@ void DestroyFlag(CommandLineFlag* flag) NO_THREAD_SAFETY_ANALYSIS {
}
}
+} // namespace
+
// --------------------------------------------------------------------
// FlagRegistry
// A FlagRegistry singleton object holds all flag objects indexed
@@ -105,8 +101,6 @@ class FlagPtrMap {
};
constexpr size_t FlagPtrMap::kNumBuckets;
-} // namespace
-
class FlagRegistry {
public:
FlagRegistry() = default;
@@ -292,10 +286,10 @@ class FlagSaverImpl {
saved.op = flag->op;
saved.marshalling_op = flag->marshalling_op;
{
- absl::MutexLock l(InitFlagIfNecessary(flag));
+ absl::MutexLock l(flag->InitFlagIfNecessary());
saved.validator = flag->validator;
saved.modified = flag->modified;
- saved.on_command_line = flag->IsSpecifiedOnCommandLine();
+ saved.on_command_line = flag->on_command_line;
saved.current = Clone(saved.op, flag->cur);
saved.default_value = Clone(saved.op, flag->def);
saved.counter = flag->counter;
@@ -318,34 +312,34 @@ class FlagSaverImpl {
bool restored = false;
{
- absl::Mutex* mu = InitFlagIfNecessary(flag);
- absl::MutexLock l(mu);
+ absl::MutexLock l(flag->InitFlagIfNecessary());
flag->validator = src.validator;
flag->modified = src.modified;
flag->on_command_line = src.on_command_line;
if (flag->counter != src.counter ||
ChangedDirectly(flag, src.default_value, flag->def)) {
- flag->counter++;
+ restored = true;
Copy(src.op, src.default_value, flag->def);
}
if (flag->counter != src.counter ||
ChangedDirectly(flag, src.current, flag->cur)) {
restored = true;
- flag->counter++;
Copy(src.op, src.current, flag->cur);
- UpdateCopy(flag, mu);
-
- // Revalidate the flag because the validator might store state based
- // on the flag's value, which just changed due to the restore.
- // Failing validation is ignored because it's assumed that the flag
- // was valid previously and there's little that can be done about it
- // here, anyway.
- Validate(flag, flag->cur);
+ UpdateCopy(flag);
+ flag->InvokeCallback();
}
}
- // Log statements must be done when no flag lock is held.
if (restored) {
+ flag->counter++;
+
+ // Revalidate the flag because the validator might store state based
+ // on the flag's value, which just changed due to the restore.
+ // Failing validation is ignored because it's assumed that the flag
+ // was valid previously and there's little that can be done about it
+ // here, anyway.
+ flag->ValidateInputValue(flag->CurrentValue());
+
ABSL_INTERNAL_LOG(
INFO, absl::StrCat("Restore saved value of ", flag->Name(), ": ",
Unparse(src.marshalling_op, src.current)));
@@ -412,13 +406,17 @@ void FillCommandLineFlagInfo(CommandLineFlag* flag,
result->description = flag->Help();
result->filename = flag->Filename();
- UpdateModifiedBit(flag);
+ if (!flag->IsAbseilFlag()) {
+ if (!flag->IsModified() && ChangedDirectly(flag, flag->cur, flag->def)) {
+ flag->modified = true;
+ }
+ }
- absl::MutexLock l(InitFlagIfNecessary(flag));
result->current_value = flag->CurrentValue();
result->default_value = flag->DefaultValue();
- result->is_default = !flag->modified;
- result->has_validator_fn = (flag->validator != nullptr);
+ result->is_default = !flag->IsModified();
+ result->has_validator_fn = flag->HasValidatorFn();
+ absl::MutexLock l(flag->InitFlagIfNecessary());
result->flag_ptr = flag->IsAbseilFlag() ? nullptr : flag->cur;
}
diff --git a/absl/flags/internal/type_erased.cc b/absl/flags/internal/type_erased.cc
index cc103983..2984291c 100644
--- a/absl/flags/internal/type_erased.cc
+++ b/absl/flags/internal/type_erased.cc
@@ -32,7 +32,6 @@ bool GetCommandLineOption(absl::string_view name, std::string* value) {
return false;
}
- absl::MutexLock l(InitFlagIfNecessary(flag));
*value = flag->CurrentValue();
return true;
}
@@ -88,22 +87,9 @@ bool SetCommandLineOptionWithMode(absl::string_view name,
bool IsValidFlagValue(absl::string_view name, absl::string_view value) {
CommandLineFlag* flag = flags_internal::FindCommandLineFlag(name);
- if (flag == nullptr) {
- return false;
- }
-
- if (flag->IsRetired()) {
- return true;
- }
- // No need to lock the flag since we are not mutating it.
- void* obj = Clone(flag->op, flag->def);
- std::string ignored_error;
- const bool result =
- flags_internal::Parse(flag->marshalling_op, value, obj, &ignored_error) &&
- Validate(flag, obj);
- Delete(flag->op, obj);
- return result;
+ return flag != nullptr &&
+ (flag->IsRetired() || flag->ValidateInputValue(value));
}
// --------------------------------------------------------------------
@@ -111,7 +97,6 @@ bool IsValidFlagValue(absl::string_view name, absl::string_view value) {
bool SpecifiedOnCommandLine(absl::string_view name) {
CommandLineFlag* flag = flags_internal::FindCommandLineFlag(name);
if (flag != nullptr && !flag->IsRetired()) {
- absl::MutexLock l(InitFlagIfNecessary(flag));
return flag->IsSpecifiedOnCommandLine();
}
return false;
diff --git a/absl/flags/internal/usage.cc b/absl/flags/internal/usage.cc
index b1ff8b83..aac02db6 100644
--- a/absl/flags/internal/usage.cc
+++ b/absl/flags/internal/usage.cc
@@ -21,11 +21,11 @@
#include "absl/flags/flag.h"
#include "absl/flags/internal/path_util.h"
#include "absl/flags/internal/program_name.h"
-#include "absl/flags/usage.h"
#include "absl/flags/usage_config.h"
#include "absl/strings/ascii.h"
#include "absl/strings/str_cat.h"
#include "absl/strings/str_split.h"
+#include "absl/strings/string_view.h"
#include "absl/synchronization/mutex.h"
ABSL_FLAG(bool, help, false,
@@ -185,7 +185,7 @@ void FlagHelpHumanReadable(const flags_internal::CommandLineFlag& flag,
}
printer.Write(absl::StrCat("default: ", dflt_val, ";"));
- if (flag.modified) {
+ if (flag.IsModified()) {
std::string curr_val = flag.CurrentValue();
if (flag.IsOfType<std::string>()) {
curr_val = absl::StrCat("\"", curr_val, "\"");
@@ -202,10 +202,10 @@ void FlagHelpHumanReadable(const flags_internal::CommandLineFlag& flag,
// STRIP_FLAG_HELP 1' then this flag will not be displayed by '--help'
// and its variants.
void FlagsHelpImpl(std::ostream& out, flags_internal::FlagKindFilter filter_cb,
- HelpFormat format = HelpFormat::kHumanReadable) {
+ HelpFormat format, absl::string_view program_usage_message) {
if (format == HelpFormat::kHumanReadable) {
out << flags_internal::ShortProgramInvocationName() << ": "
- << absl::ProgramUsageMessage() << "\n\n";
+ << program_usage_message << "\n\n";
} else {
// XML schema is not a part of our public API for now.
out << "<?xml version=\"1.0\"?>\n"
@@ -214,7 +214,7 @@ void FlagsHelpImpl(std::ostream& out, flags_internal::FlagKindFilter filter_cb,
// The program name and usage.
<< XMLElement("program", flags_internal::ShortProgramInvocationName())
<< '\n'
- << XMLElement("usage", absl::ProgramUsageMessage()) << '\n';
+ << XMLElement("usage", program_usage_message) << '\n';
}
// Map of package name to
@@ -228,8 +228,6 @@ void FlagsHelpImpl(std::ostream& out, flags_internal::FlagKindFilter filter_cb,
matching_flags;
flags_internal::ForEachFlag([&](flags_internal::CommandLineFlag* flag) {
- absl::MutexLock l(InitFlagIfNecessary(flag));
-
std::string flag_filename = flag->Filename();
// Ignore retired flags.
@@ -292,44 +290,51 @@ void FlagHelp(std::ostream& out, const flags_internal::CommandLineFlag& flag,
// --------------------------------------------------------------------
// Produces the help messages for all flags matching the filter.
// If filter is empty produces help messages for all flags.
-void FlagsHelp(std::ostream& out, absl::string_view filter, HelpFormat format) {
+void FlagsHelp(std::ostream& out, absl::string_view filter, HelpFormat format,
+ absl::string_view program_usage_message) {
flags_internal::FlagKindFilter filter_cb = [&](absl::string_view filename) {
return filter.empty() || filename.find(filter) != absl::string_view::npos;
};
- flags_internal::FlagsHelpImpl(out, filter_cb, format);
+ flags_internal::FlagsHelpImpl(out, filter_cb, format, program_usage_message);
}
// --------------------------------------------------------------------
// Checks all the 'usage' command line flags to see if any have been set.
// If so, handles them appropriately.
-int HandleUsageFlags(std::ostream& out) {
+int HandleUsageFlags(std::ostream& out,
+ absl::string_view program_usage_message) {
if (absl::GetFlag(FLAGS_helpshort)) {
flags_internal::FlagsHelpImpl(
out, flags_internal::GetUsageConfig().contains_helpshort_flags,
- HelpFormat::kHumanReadable);
+ HelpFormat::kHumanReadable, program_usage_message);
return 1;
}
if (absl::GetFlag(FLAGS_helpfull)) {
// show all options
- flags_internal::FlagsHelp(out);
+ flags_internal::FlagsHelp(out, "", HelpFormat::kHumanReadable,
+ program_usage_message);
return 1;
}
if (!absl::GetFlag(FLAGS_helpon).empty()) {
flags_internal::FlagsHelp(
- out, absl::StrCat("/", absl::GetFlag(FLAGS_helpon), "."));
+ out, absl::StrCat("/", absl::GetFlag(FLAGS_helpon), "."),
+ HelpFormat::kHumanReadable, program_usage_message);
return 1;
}
if (!absl::GetFlag(FLAGS_helpmatch).empty()) {
- flags_internal::FlagsHelp(out, absl::GetFlag(FLAGS_helpmatch));
+ flags_internal::FlagsHelp(out, absl::GetFlag(FLAGS_helpmatch),
+ HelpFormat::kHumanReadable,
+ program_usage_message);
return 1;
}
if (absl::GetFlag(FLAGS_help)) {
flags_internal::FlagsHelpImpl(
- out, flags_internal::GetUsageConfig().contains_help_flags);
+ out, flags_internal::GetUsageConfig().contains_help_flags,
+ HelpFormat::kHumanReadable, program_usage_message);
out << "\nTry --helpfull to get a list of all flags.\n";
@@ -338,7 +343,8 @@ int HandleUsageFlags(std::ostream& out) {
if (absl::GetFlag(FLAGS_helppackage)) {
flags_internal::FlagsHelpImpl(
- out, flags_internal::GetUsageConfig().contains_helppackage_flags);
+ out, flags_internal::GetUsageConfig().contains_helppackage_flags,
+ HelpFormat::kHumanReadable, program_usage_message);
out << "\nTry --helpfull to get a list of all flags.\n";
diff --git a/absl/flags/internal/usage.h b/absl/flags/internal/usage.h
index 33f3f969..76075b08 100644
--- a/absl/flags/internal/usage.h
+++ b/absl/flags/internal/usage.h
@@ -47,8 +47,8 @@ void FlagHelp(std::ostream& out, const flags_internal::CommandLineFlag& flag,
// .../path/to/file.<ext>
// for any extension 'ext'. If the filter is empty this function produces help
// messages for all flags.
-void FlagsHelp(std::ostream& out, absl::string_view filter = {},
- HelpFormat format = HelpFormat::kHumanReadable);
+void FlagsHelp(std::ostream& out, absl::string_view filter,
+ HelpFormat format, absl::string_view program_usage_message);
// --------------------------------------------------------------------
@@ -60,7 +60,8 @@ void FlagsHelp(std::ostream& out, absl::string_view filter = {},
// -1 - if no usage flags were set on a commmand line.
// Non negative return values are expected to be used as an exit code for a
// binary.
-int HandleUsageFlags(std::ostream& out);
+int HandleUsageFlags(std::ostream& out,
+ absl::string_view program_usage_message);
} // namespace flags_internal
} // namespace absl
diff --git a/absl/flags/internal/usage_test.cc b/absl/flags/internal/usage_test.cc
index fa121fc9..5e5f7a84 100644
--- a/absl/flags/internal/usage_test.cc
+++ b/absl/flags/internal/usage_test.cc
@@ -36,6 +36,8 @@ ABSL_FLAG(double, usage_reporting_test_flag_03, 1.03,
ABSL_FLAG(int64_t, usage_reporting_test_flag_04, 1000000000000004L,
"usage_reporting_test_flag_04 help message");
+static const char kTestUsageMessage[] = "Custom usage message";
+
struct UDT {
UDT() = default;
UDT(const UDT&) = default;
@@ -83,7 +85,7 @@ class UsageReportingTest : public testing::Test {
using UsageReportingDeathTest = UsageReportingTest;
TEST_F(UsageReportingDeathTest, TestSetProgramUsageMessage) {
- EXPECT_EQ(absl::ProgramUsageMessage(), "Custom usage message");
+ EXPECT_EQ(absl::ProgramUsageMessage(), kTestUsageMessage);
#ifndef _WIN32
// TODO(rogeeff): figure out why this does not work on Windows.
@@ -175,22 +177,22 @@ TEST_F(UsageReportingTest, TestFlagsHelpHRF) {
std::stringstream test_buf_01;
flags::FlagsHelp(test_buf_01, "usage_test.cc",
- flags::HelpFormat::kHumanReadable);
+ flags::HelpFormat::kHumanReadable, kTestUsageMessage);
EXPECT_EQ(test_buf_01.str(), usage_test_flags_out);
std::stringstream test_buf_02;
flags::FlagsHelp(test_buf_02, "flags/internal/usage_test.cc",
- flags::HelpFormat::kHumanReadable);
+ flags::HelpFormat::kHumanReadable, kTestUsageMessage);
EXPECT_EQ(test_buf_02.str(), usage_test_flags_out);
std::stringstream test_buf_03;
- flags::FlagsHelp(test_buf_03, "usage_test",
- flags::HelpFormat::kHumanReadable);
+ flags::FlagsHelp(test_buf_03, "usage_test", flags::HelpFormat::kHumanReadable,
+ kTestUsageMessage);
EXPECT_EQ(test_buf_03.str(), usage_test_flags_out);
std::stringstream test_buf_04;
flags::FlagsHelp(test_buf_04, "flags/invalid_file_name.cc",
- flags::HelpFormat::kHumanReadable);
+ flags::HelpFormat::kHumanReadable, kTestUsageMessage);
EXPECT_EQ(test_buf_04.str(),
R"(usage_test: Custom usage message
@@ -198,7 +200,8 @@ TEST_F(UsageReportingTest, TestFlagsHelpHRF) {
)");
std::stringstream test_buf_05;
- flags::FlagsHelp(test_buf_05, "", flags::HelpFormat::kHumanReadable);
+ flags::FlagsHelp(test_buf_05, "", flags::HelpFormat::kHumanReadable,
+ kTestUsageMessage);
std::string test_out = test_buf_05.str();
absl::string_view test_out_str(test_out);
EXPECT_TRUE(
@@ -217,7 +220,7 @@ TEST_F(UsageReportingTest, TestFlagsHelpHRF) {
TEST_F(UsageReportingTest, TestNoUsageFlags) {
std::stringstream test_buf;
- EXPECT_EQ(flags::HandleUsageFlags(test_buf), -1);
+ EXPECT_EQ(flags::HandleUsageFlags(test_buf, kTestUsageMessage), -1);
}
// --------------------------------------------------------------------
@@ -226,7 +229,7 @@ TEST_F(UsageReportingTest, TestUsageFlag_helpshort) {
absl::SetFlag(&FLAGS_helpshort, true);
std::stringstream test_buf;
- EXPECT_EQ(flags::HandleUsageFlags(test_buf), 1);
+ EXPECT_EQ(flags::HandleUsageFlags(test_buf, kTestUsageMessage), 1);
EXPECT_EQ(test_buf.str(),
R"(usage_test: Custom usage message
@@ -250,7 +253,7 @@ TEST_F(UsageReportingTest, TestUsageFlag_help) {
absl::SetFlag(&FLAGS_help, true);
std::stringstream test_buf;
- EXPECT_EQ(flags::HandleUsageFlags(test_buf), 1);
+ EXPECT_EQ(flags::HandleUsageFlags(test_buf, kTestUsageMessage), 1);
EXPECT_EQ(test_buf.str(),
R"(usage_test: Custom usage message
@@ -276,7 +279,7 @@ TEST_F(UsageReportingTest, TestUsageFlag_helppackage) {
absl::SetFlag(&FLAGS_helppackage, true);
std::stringstream test_buf;
- EXPECT_EQ(flags::HandleUsageFlags(test_buf), 1);
+ EXPECT_EQ(flags::HandleUsageFlags(test_buf, kTestUsageMessage), 1);
EXPECT_EQ(test_buf.str(),
R"(usage_test: Custom usage message
@@ -302,10 +305,9 @@ TEST_F(UsageReportingTest, TestUsageFlag_version) {
absl::SetFlag(&FLAGS_version, true);
std::stringstream test_buf;
- EXPECT_EQ(flags::HandleUsageFlags(test_buf), 0);
+ EXPECT_EQ(flags::HandleUsageFlags(test_buf, kTestUsageMessage), 0);
#ifndef NDEBUG
- EXPECT_EQ(test_buf.str(),
- "usage_test\nDebug build (NDEBUG not #defined)\n");
+ EXPECT_EQ(test_buf.str(), "usage_test\nDebug build (NDEBUG not #defined)\n");
#else
EXPECT_EQ(test_buf.str(), "usage_test\n");
#endif
@@ -317,7 +319,7 @@ TEST_F(UsageReportingTest, TestUsageFlag_only_check_args) {
absl::SetFlag(&FLAGS_only_check_args, true);
std::stringstream test_buf;
- EXPECT_EQ(flags::HandleUsageFlags(test_buf), 0);
+ EXPECT_EQ(flags::HandleUsageFlags(test_buf, kTestUsageMessage), 0);
EXPECT_EQ(test_buf.str(), "");
}
@@ -327,7 +329,7 @@ TEST_F(UsageReportingTest, TestUsageFlag_helpon) {
absl::SetFlag(&FLAGS_helpon, "bla-bla");
std::stringstream test_buf_01;
- EXPECT_EQ(flags::HandleUsageFlags(test_buf_01), 1);
+ EXPECT_EQ(flags::HandleUsageFlags(test_buf_01, kTestUsageMessage), 1);
EXPECT_EQ(test_buf_01.str(),
R"(usage_test: Custom usage message
@@ -337,7 +339,7 @@ TEST_F(UsageReportingTest, TestUsageFlag_helpon) {
absl::SetFlag(&FLAGS_helpon, "usage_test");
std::stringstream test_buf_02;
- EXPECT_EQ(flags::HandleUsageFlags(test_buf_02), 1);
+ EXPECT_EQ(flags::HandleUsageFlags(test_buf_02, kTestUsageMessage), 1);
EXPECT_EQ(test_buf_02.str(),
R"(usage_test: Custom usage message
@@ -362,7 +364,7 @@ TEST_F(UsageReportingTest, TestUsageFlag_helpon) {
int main(int argc, char* argv[]) {
absl::GetFlag(FLAGS_undefok); // Force linking of parse.cc
flags::SetProgramInvocationName("usage_test");
- absl::SetProgramUsageMessage("Custom usage message");
+ absl::SetProgramUsageMessage(kTestUsageMessage);
::testing::InitGoogleTest(&argc, argv);
return RUN_ALL_TESTS();
diff --git a/absl/flags/parse.cc b/absl/flags/parse.cc
index 3caaa1c2..e9dd4204 100644
--- a/absl/flags/parse.cc
+++ b/absl/flags/parse.cc
@@ -16,6 +16,7 @@
#include "absl/flags/parse.h"
#include <stdlib.h>
+
#include <fstream>
#include <iostream>
#include <tuple>
@@ -28,6 +29,7 @@
#include "absl/flags/internal/program_name.h"
#include "absl/flags/internal/registry.h"
#include "absl/flags/internal/usage.h"
+#include "absl/flags/usage.h"
#include "absl/flags/usage_config.h"
#include "absl/strings/str_cat.h"
#include "absl/strings/strip.h"
@@ -280,22 +282,7 @@ void CheckDefaultValuesParsingRoundtrip() {
IGNORE_TYPE(std::vector<std::string>)
#undef IGNORE_TYPE
- absl::MutexLock lock(InitFlagIfNecessary(flag));
-
- std::string v = flag->DefaultValue();
- void* dst = Clone(flag->op, flag->def);
- std::string error;
- if (!flags_internal::Parse(flag->marshalling_op, v, dst, &error)) {
- ABSL_INTERNAL_LOG(
- FATAL,
- absl::StrCat("Flag ", flag->Name(), " (from ", flag->Filename(),
- "): std::string form of default value '", v,
- "' could not be parsed; error=", error));
- }
-
- // We do not compare dst to def since parsing/unparsing may make
- // small changes, e.g., precision loss for floating point types.
- Delete(flag->op, dst);
+ flag->CheckDefaultValueParsingRoundtrip();
});
#endif
}
@@ -717,12 +704,14 @@ std::vector<char*> ParseCommandLineImpl(int argc, char* argv[],
#endif
if (!success) {
- flags_internal::HandleUsageFlags(std::cout);
+ flags_internal::HandleUsageFlags(std::cout,
+ ProgramUsageMessage());
std::exit(1);
}
if (usage_flag_act == UsageFlagsAction::kHandleUsage) {
- int exit_code = flags_internal::HandleUsageFlags(std::cout);
+ int exit_code = flags_internal::HandleUsageFlags(
+ std::cout, ProgramUsageMessage());
if (exit_code != -1) {
std::exit(exit_code);
diff --git a/absl/hash/hash_test.cc b/absl/hash/hash_test.cc
index bab560bd..9a667ba7 100644
--- a/absl/hash/hash_test.cc
+++ b/absl/hash/hash_test.cc
@@ -288,7 +288,6 @@ TEST(HashValueTest, Strings) {
// Also check that nested types maintain the same hash.
const WrapInTuple t{};
EXPECT_TRUE(absl::VerifyTypeImplementsAbslHashCorrectly(std::make_tuple(
- //
t(std::string()), t(absl::string_view()),
t(std::string("")), t(absl::string_view("")),
t(std::string(small)), t(absl::string_view(small)),
diff --git a/absl/hash/internal/hash.h b/absl/hash/internal/hash.h
index 18665173..4ff4a126 100644
--- a/absl/hash/internal/hash.h
+++ b/absl/hash/internal/hash.h
@@ -640,7 +640,8 @@ class CityHashState : public HashStateBase<CityHashState> {
#endif // ABSL_HAVE_INTRINSIC_INT128
static constexpr uint64_t kMul =
- sizeof(size_t) == 4 ? uint64_t{0xcc9e2d51} : uint64_t{0x9ddfea08eb382d69};
+ sizeof(size_t) == 4 ? uint64_t{0xcc9e2d51}
+ : uint64_t{0x9ddfea08eb382d69};
template <typename T>
using IntegralFastPath =
diff --git a/absl/numeric/int128.h b/absl/numeric/int128.h
index 2f5b8ad7..10be8eca 100644
--- a/absl/numeric/int128.h
+++ b/absl/numeric/int128.h
@@ -19,8 +19,8 @@
//
// This header file defines 128-bit integer types.
//
-// Currently, this file defines `uint128`, an unsigned 128-bit integer; a signed
-// 128-bit integer is forthcoming.
+// Currently, this file defines `uint128`, an unsigned 128-bit integer;
+// a signed 128-bit integer is forthcoming.
#ifndef ABSL_NUMERIC_INT128_H_
#define ABSL_NUMERIC_INT128_H_
diff --git a/absl/random/internal/fast_uniform_bits.h b/absl/random/internal/fast_uniform_bits.h
index 184a2708..e8df92f3 100644
--- a/absl/random/internal/fast_uniform_bits.h
+++ b/absl/random/internal/fast_uniform_bits.h
@@ -22,11 +22,18 @@
namespace absl {
namespace random_internal {
+// Returns true if the input value is zero or a power of two. Useful for
+// determining if the range of output values in a URBG
+template <typename UIntType>
+constexpr bool IsPowerOfTwoOrZero(UIntType n) {
+ return (n == 0) || ((n & (n - 1)) == 0);
+}
+
// Computes the length of the range of values producible by the URBG, or returns
// zero if that would encompass the entire range of representable values in
// URBG::result_type.
template <typename URBG>
-constexpr typename URBG::result_type constexpr_range() {
+constexpr typename URBG::result_type RangeSize() {
using result_type = typename URBG::result_type;
return ((URBG::max)() == (std::numeric_limits<result_type>::max)() &&
(URBG::min)() == std::numeric_limits<result_type>::lowest())
@@ -34,6 +41,42 @@ constexpr typename URBG::result_type constexpr_range() {
: (URBG::max)() - (URBG::min)() + result_type{1};
}
+template <typename UIntType>
+constexpr UIntType LargestPowerOfTwoLessThanOrEqualTo(UIntType n) {
+ return n < 2 ? n : 2 * LargestPowerOfTwoLessThanOrEqualTo(n / 2);
+}
+
+// Given a URBG generating values in the closed interval [Lo, Hi], returns the
+// largest power of two less than or equal to `Hi - Lo + 1`.
+template <typename URBG>
+constexpr typename URBG::result_type PowerOfTwoSubRangeSize() {
+ return LargestPowerOfTwoLessThanOrEqualTo(RangeSize<URBG>());
+}
+
+// Computes the floor of the log. (i.e., std::floor(std::log2(N));
+template <typename UIntType>
+constexpr UIntType IntegerLog2(UIntType n) {
+ return (n <= 1) ? 0 : 1 + IntegerLog2(n / 2);
+}
+
+// Returns the number of bits of randomness returned through
+// `PowerOfTwoVariate(urbg)`.
+template <typename URBG>
+constexpr size_t NumBits() {
+ return RangeSize<URBG>() == 0
+ ? std::numeric_limits<typename URBG::result_type>::digits
+ : IntegerLog2(PowerOfTwoSubRangeSize<URBG>());
+}
+
+// Given a shift value `n`, constructs a mask with exactly the low `n` bits set.
+// If `n == 0`, all bits are set.
+template <typename UIntType>
+constexpr UIntType MaskFromShift(UIntType n) {
+ return ((n % std::numeric_limits<UIntType>::digits) == 0)
+ ? ~UIntType{0}
+ : (UIntType{1} << n) - UIntType{1};
+}
+
// FastUniformBits implements a fast path to acquire uniform independent bits
// from a type which conforms to the [rand.req.urbg] concept.
// Parameterized by:
@@ -45,14 +88,6 @@ constexpr typename URBG::result_type constexpr_range() {
// generator that will outlive the std::independent_bits_engine instance.
template <typename UIntType = uint64_t>
class FastUniformBits {
- static_assert(std::is_unsigned<UIntType>::value,
- "Class-template FastUniformBits<> must be parameterized using "
- "an unsigned type.");
-
- // `kWidth` is the width, in binary digits, of the output. By default it is
- // the number of binary digits in the `result_type`.
- static constexpr size_t kWidth = std::numeric_limits<UIntType>::digits;
-
public:
using result_type = UIntType;
@@ -65,14 +100,47 @@ class FastUniformBits {
result_type operator()(URBG& g); // NOLINT(runtime/references)
private:
- // Variate() generates a single random variate, always returning a value
- // in the closed interval [0 ... FastUniformBitsURBGConstants::kRangeMask]
- // (kRangeMask+1 is a power of 2).
+ static_assert(std::is_unsigned<UIntType>::value,
+ "Class-template FastUniformBits<> must be parameterized using "
+ "an unsigned type.");
+
+ // PowerOfTwoVariate() generates a single random variate, always returning a
+ // value in the half-open interval `[0, PowerOfTwoSubRangeSize<URBG>())`. If
+ // the URBG already generates values in a power-of-two range, the generator
+ // itself is used. Otherwise, we use rejection sampling on the largest
+ // possible power-of-two-sized subrange.
+ struct PowerOfTwoTag {};
+ struct RejectionSamplingTag {};
template <typename URBG>
- typename URBG::result_type Variate(URBG& g); // NOLINT(runtime/references)
+ static typename URBG::result_type PowerOfTwoVariate(
+ URBG& g) { // NOLINT(runtime/references)
+ using tag =
+ typename std::conditional<IsPowerOfTwoOrZero(RangeSize<URBG>()),
+ PowerOfTwoTag, RejectionSamplingTag>::type;
+ return PowerOfTwoVariate(g, tag{});
+ }
+
+ template <typename URBG>
+ static typename URBG::result_type PowerOfTwoVariate(
+ URBG& g, // NOLINT(runtime/references)
+ PowerOfTwoTag) {
+ return g() - (URBG::min)();
+ }
- // generate() generates a random value, dispatched on whether
- // the underlying URNG must loop over multiple calls or not.
+ template <typename URBG>
+ static typename URBG::result_type PowerOfTwoVariate(
+ URBG& g, // NOLINT(runtime/references)
+ RejectionSamplingTag) {
+ // Use rejection sampling to ensure uniformity across the range.
+ typename URBG::result_type u;
+ do {
+ u = g() - (URBG::min)();
+ } while (u >= PowerOfTwoSubRangeSize<URBG>());
+ return u;
+ }
+
+ // Generate() generates a random value, dispatched on whether
+ // the underlying URBG must loop over multiple calls or not.
template <typename URBG>
result_type Generate(URBG& g, // NOLINT(runtime/references)
std::true_type /* avoid_looping */);
@@ -82,196 +150,107 @@ class FastUniformBits {
std::false_type /* avoid_looping */);
};
-// FastUniformBitsURBGConstants computes the URBG-derived constants used
-// by FastUniformBits::Generate and FastUniformBits::Variate.
-// Parameterized by the FastUniformBits parameter:
-// `URBG`: The underlying UniformRandomNumberGenerator.
-//
-// The values here indicate the URBG range as well as providing an indicator
-// whether the URBG output is a power of 2, and kRangeMask, which allows masking
-// the generated output to kRangeBits.
+template <typename UIntType>
template <typename URBG>
-class FastUniformBitsURBGConstants {
- // Computes the floor of the log. (i.e., std::floor(std::log2(N));
- static constexpr size_t constexpr_log2(size_t n) {
- return (n <= 1) ? 0 : 1 + constexpr_log2(n / 2);
- }
-
- // Computes a mask of n bits for the URBG::result_type.
- static constexpr typename URBG::result_type constexpr_mask(size_t n) {
- return (typename URBG::result_type(1) << n) - 1;
- }
-
- public:
- using result_type = typename URBG::result_type;
-
- // The range of the URNG, max - min + 1, or zero if that result would cause
- // overflow.
- static constexpr result_type kRange = constexpr_range<URBG>();
-
- static constexpr bool kPowerOfTwo =
- (kRange == 0) || ((kRange & (kRange - 1)) == 0);
-
- // kRangeBits describes the number number of bits suitable to mask off of URNG
- // variate, which is:
- // kRangeBits = floor(log2(kRange))
- static constexpr size_t kRangeBits =
- kRange == 0 ? std::numeric_limits<result_type>::digits
- : constexpr_log2(kRange);
-
- // kRangeMask is the mask used when sampling variates from the URNG when the
- // width of the URNG range is not a power of 2.
+typename FastUniformBits<UIntType>::result_type
+FastUniformBits<UIntType>::operator()(URBG& g) { // NOLINT(runtime/references)
+ // kRangeMask is the mask used when sampling variates from the URBG when the
+ // width of the URBG range is not a power of 2.
// Y = (2 ^ kRange) - 1
- static constexpr result_type kRangeMask =
- kRange == 0 ? (std::numeric_limits<result_type>::max)()
- : constexpr_mask(kRangeBits);
-
- static_assert((URBG::max)() != (URBG::min)(),
- "Class-template FastUniformBitsURBGConstants<> "
+ static_assert((URBG::max)() > (URBG::min)(),
"URBG::max and URBG::min may not be equal.");
-
- static_assert(std::is_unsigned<result_type>::value,
- "Class-template FastUniformBitsURBGConstants<> "
- "URBG::result_type must be unsigned.");
-
- static_assert(kRangeMask > 0,
- "Class-template FastUniformBitsURBGConstants<> "
- "URBG does not generate sufficient random bits.");
-
- static_assert(kRange == 0 ||
- kRangeBits < std::numeric_limits<result_type>::digits,
- "Class-template FastUniformBitsURBGConstants<> "
- "URBG range computation error.");
-};
-
-// FastUniformBitsLoopingConstants computes the looping constants used
-// by FastUniformBits::Generate. These constants indicate how multiple
-// URBG::result_type values are combined into an output_value.
-// Parameterized by the FastUniformBits parameters:
-// `UIntType`: output type.
-// `URNG`: The underlying UniformRandomNumberGenerator.
-//
-// The looping constants describe the sets of loop counters and mask values
-// which control how individual variates are combined the final output. The
-// algorithm ensures that the number of bits used by any individual call differs
-// by at-most one bit from any other call. This is simplified into constants
-// which describe two loops, with the second loop parameters providing one extra
-// bit per variate.
-//
-// See [rand.adapt.ibits] for more details on the use of these constants.
-template <typename UIntType, typename URBG>
-class FastUniformBitsLoopingConstants {
- private:
- static constexpr size_t kWidth = std::numeric_limits<UIntType>::digits;
using urbg_result_type = typename URBG::result_type;
- using uint_result_type = UIntType;
-
- public:
- using result_type =
- typename std::conditional<(sizeof(urbg_result_type) <=
- sizeof(uint_result_type)),
- uint_result_type, urbg_result_type>::type;
-
- private:
- // Estimate N as ceil(width / urng width), and W0 as (width / N).
- static constexpr size_t kRangeBits =
- FastUniformBitsURBGConstants<URBG>::kRangeBits;
-
- // The range of the URNG, max - min + 1, or zero if that result would cause
- // overflow.
- static constexpr result_type kRange = constexpr_range<URBG>();
- static constexpr size_t kEstimateN =
- kWidth / kRangeBits + (kWidth % kRangeBits != 0);
- static constexpr size_t kEstimateW0 = kWidth / kEstimateN;
- static constexpr result_type kEstimateY0 = (kRange >> kEstimateW0)
- << kEstimateW0;
-
- public:
- // Parameters for the two loops:
- // kN0, kN1 are the number of underlying calls required for each loop.
- // KW0, kW1 are shift widths for each loop.
- //
- static constexpr size_t kN1 = (kRange - kEstimateY0) >
- (kEstimateY0 / kEstimateN)
- ? kEstimateN + 1
- : kEstimateN;
- static constexpr size_t kN0 = kN1 - (kWidth % kN1);
- static constexpr size_t kW0 = kWidth / kN1;
- static constexpr size_t kW1 = kW0 + 1;
-
- static constexpr result_type kM0 = (result_type(1) << kW0) - 1;
- static constexpr result_type kM1 = (result_type(1) << kW1) - 1;
-
- static_assert(
- kW0 <= kRangeBits,
- "Class-template FastUniformBitsLoopingConstants::kW0 too large.");
-
- static_assert(
- kW0 > 0,
- "Class-template FastUniformBitsLoopingConstants::kW0 too small.");
-};
-
-template <typename UIntType>
-template <typename URBG>
-typename FastUniformBits<UIntType>::result_type
-FastUniformBits<UIntType>::operator()(
- URBG& g) { // NOLINT(runtime/references)
- using constants = FastUniformBitsURBGConstants<URBG>;
- return Generate(
- g, std::integral_constant<bool, constants::kRangeMask >= (max)()>{});
-}
-
-template <typename UIntType>
-template <typename URBG>
-typename URBG::result_type FastUniformBits<UIntType>::Variate(
- URBG& g) { // NOLINT(runtime/references)
- using constants = FastUniformBitsURBGConstants<URBG>;
- if (constants::kPowerOfTwo) {
- return g() - (URBG::min)();
- }
-
- // Use rejection sampling to ensure uniformity across the range.
- typename URBG::result_type u;
- do {
- u = g() - (URBG::min)();
- } while (u > constants::kRangeMask);
- return u;
+ constexpr urbg_result_type kRangeMask =
+ RangeSize<URBG>() == 0
+ ? (std::numeric_limits<urbg_result_type>::max)()
+ : static_cast<urbg_result_type>(PowerOfTwoSubRangeSize<URBG>() - 1);
+ return Generate(g, std::integral_constant<bool, (kRangeMask >= (max)())>{});
}
template <typename UIntType>
template <typename URBG>
typename FastUniformBits<UIntType>::result_type
-FastUniformBits<UIntType>::Generate(
- URBG& g, // NOLINT(runtime/references)
- std::true_type /* avoid_looping */) {
+FastUniformBits<UIntType>::Generate(URBG& g, // NOLINT(runtime/references)
+ std::true_type /* avoid_looping */) {
// The width of the result_type is less than than the width of the random bits
- // provided by URNG. Thus, generate a single value and then simply mask off
+ // provided by URBG. Thus, generate a single value and then simply mask off
// the required bits.
- return Variate(g) & (max)();
+
+ return PowerOfTwoVariate(g) & (max)();
}
template <typename UIntType>
template <typename URBG>
typename FastUniformBits<UIntType>::result_type
-FastUniformBits<UIntType>::Generate(
- URBG& g, // NOLINT(runtime/references)
- std::false_type /* avoid_looping */) {
- // The width of the result_type is wider than the number of random bits
- // provided by URNG. Thus we merge several variates of URNG into the result
- // using a shift and mask. The constants type generates the parameters used
- // ensure that the bits are distributed across all the invocations of the
- // underlying URNG.
- using constants = FastUniformBitsLoopingConstants<UIntType, URBG>;
+FastUniformBits<UIntType>::Generate(URBG& g, // NOLINT(runtime/references)
+ std::false_type /* avoid_looping */) {
+ // See [rand.adapt.ibits] for more details on the constants calculated below.
+ //
+ // It is preferable to use roughly the same number of bits from each generator
+ // call, however this is only possible when the number of bits provided by the
+ // URBG is a divisor of the number of bits in `result_type`. In all other
+ // cases, the number of bits used cannot always be the same, but it can be
+ // guaranteed to be off by at most 1. Thus we run two loops, one with a
+ // smaller bit-width size (`kSmallWidth`) and one with a larger width size
+ // (satisfying `kLargeWidth == kSmallWidth + 1`). The loops are run
+ // `kSmallIters` and `kLargeIters` times respectively such
+ // that
+ //
+ // `kTotalWidth == kSmallIters * kSmallWidth
+ // + kLargeIters * kLargeWidth`
+ //
+ // where `kTotalWidth` is the total number of bits in `result_type`.
+ //
+ constexpr size_t kTotalWidth = std::numeric_limits<result_type>::digits;
+ constexpr size_t kUrbgWidth = NumBits<URBG>();
+ constexpr size_t kTotalIters =
+ kTotalWidth / kUrbgWidth + (kTotalWidth % kUrbgWidth != 0);
+ constexpr size_t kSmallWidth = kTotalWidth / kTotalIters;
+ constexpr size_t kLargeWidth = kSmallWidth + 1;
+ //
+ // Because `kLargeWidth == kSmallWidth + 1`, it follows that
+ //
+ // `kTotalWidth == kTotalIters * kSmallWidth + kLargeIters`
+ //
+ // and therefore
+ //
+ // `kLargeIters == kTotalWidth % kSmallWidth`
+ //
+ // Intuitively, each iteration with the large width accounts for one unit
+ // of the remainder when `kTotalWidth` is divided by `kSmallWidth`. As
+ // mentioned above, if the URBG width is a divisor of `kTotalWidth`, then
+ // there would be no need for any large iterations (i.e., one loop would
+ // suffice), and indeed, in this case, `kLargeIters` would be zero.
+ constexpr size_t kLargeIters = kTotalWidth % kSmallWidth;
+ constexpr size_t kSmallIters =
+ (kTotalWidth - (kLargeWidth * kLargeIters)) / kSmallWidth;
+
+ static_assert(
+ kTotalWidth == kSmallIters * kSmallWidth + kLargeIters * kLargeWidth,
+ "Error in looping constant calculations.");
result_type s = 0;
- for (size_t n = 0; n < constants::kN0; ++n) {
- auto u = Variate(g);
- s = (s << constants::kW0) + (u & constants::kM0);
+
+ constexpr size_t kSmallShift = kSmallWidth % kTotalWidth;
+ constexpr result_type kSmallMask = MaskFromShift(result_type{kSmallShift});
+ for (size_t n = 0; n < kSmallIters; ++n) {
+ s = (s << kSmallShift) +
+ (static_cast<result_type>(PowerOfTwoVariate(g)) & kSmallMask);
}
- for (size_t n = constants::kN0; n < constants::kN1; ++n) {
- auto u = Variate(g);
- s = (s << constants::kW1) + (u & constants::kM1);
+
+ constexpr size_t kLargeShift = kLargeWidth % kTotalWidth;
+ constexpr result_type kLargeMask = MaskFromShift(result_type{kLargeShift});
+ for (size_t n = 0; n < kLargeIters; ++n) {
+ s = (s << kLargeShift) +
+ (static_cast<result_type>(PowerOfTwoVariate(g)) & kLargeMask);
}
+
+ static_assert(
+ kLargeShift == kSmallShift + 1 ||
+ (kLargeShift == 0 &&
+ kSmallShift == std::numeric_limits<result_type>::digits - 1),
+ "Error in looping constant calculations");
+
return s;
}
diff --git a/absl/random/internal/fast_uniform_bits_test.cc b/absl/random/internal/fast_uniform_bits_test.cc
index 18377944..9f2e8268 100644
--- a/absl/random/internal/fast_uniform_bits_test.cc
+++ b/absl/random/internal/fast_uniform_bits_test.cc
@@ -18,6 +18,8 @@
#include "gtest/gtest.h"
+namespace absl {
+namespace random_internal {
namespace {
template <typename IntType>
@@ -29,7 +31,7 @@ TYPED_TEST_SUITE(FastUniformBitsTypedTest, IntTypes);
TYPED_TEST(FastUniformBitsTypedTest, BasicTest) {
using Limits = std::numeric_limits<TypeParam>;
- using FastBits = absl::random_internal::FastUniformBits<TypeParam>;
+ using FastBits = FastUniformBits<TypeParam>;
EXPECT_EQ(0, FastBits::min());
EXPECT_EQ(Limits::max(), FastBits::max());
@@ -45,91 +47,226 @@ TYPED_TEST(FastUniformBitsTypedTest, BasicTest) {
}
}
-class UrngOddbits {
- public:
- using result_type = uint8_t;
- static constexpr result_type min() { return 1; }
- static constexpr result_type max() { return 0xfe; }
- result_type operator()() { return 2; }
-};
+template <typename UIntType, UIntType Lo, UIntType Hi, UIntType Val = Lo>
+struct FakeUrbg {
+ using result_type = UIntType;
-class Urng4bits {
- public:
- using result_type = uint8_t;
- static constexpr result_type min() { return 1; }
- static constexpr result_type max() { return 0xf + 1; }
- result_type operator()() { return 2; }
+ static constexpr result_type(max)() { return Hi; }
+ static constexpr result_type(min)() { return Lo; }
+ result_type operator()() { return Val; }
};
-class Urng32bits {
- public:
- using result_type = uint32_t;
- static constexpr result_type min() { return 0; }
- static constexpr result_type max() { return 0xffffffff; }
- result_type operator()() { return 1; }
-};
+using UrngOddbits = FakeUrbg<uint8_t, 1, 0xfe, 0x73>;
+using Urng4bits = FakeUrbg<uint8_t, 1, 0x10, 2>;
+using Urng31bits = FakeUrbg<uint32_t, 1, 0xfffffffe, 0x60070f03>;
+using Urng32bits = FakeUrbg<uint32_t, 0, 0xffffffff, 0x74010f01>;
-// Compile-time test to validate the helper classes used by FastUniformBits
-TEST(FastUniformBitsTest, FastUniformBitsDetails) {
- using absl::random_internal::FastUniformBitsLoopingConstants;
- using absl::random_internal::FastUniformBitsURBGConstants;
+TEST(FastUniformBitsTest, IsPowerOfTwoOrZero) {
+ EXPECT_TRUE(IsPowerOfTwoOrZero(uint8_t{0}));
+ EXPECT_TRUE(IsPowerOfTwoOrZero(uint8_t{1}));
+ EXPECT_TRUE(IsPowerOfTwoOrZero(uint8_t{2}));
+ EXPECT_FALSE(IsPowerOfTwoOrZero(uint8_t{3}));
+ EXPECT_TRUE(IsPowerOfTwoOrZero(uint8_t{16}));
+ EXPECT_FALSE(IsPowerOfTwoOrZero(uint8_t{17}));
+ EXPECT_FALSE(IsPowerOfTwoOrZero((std::numeric_limits<uint8_t>::max)()));
- // 4-bit URBG
- {
- using constants = FastUniformBitsURBGConstants<Urng4bits>;
- static_assert(constants::kPowerOfTwo == true,
- "constants::kPowerOfTwo == false");
- static_assert(constants::kRange == 16, "constants::kRange == false");
- static_assert(constants::kRangeBits == 4, "constants::kRangeBits == false");
- static_assert(constants::kRangeMask == 0x0f,
- "constants::kRangeMask == false");
- }
+ EXPECT_TRUE(IsPowerOfTwoOrZero(uint16_t{0}));
+ EXPECT_TRUE(IsPowerOfTwoOrZero(uint16_t{1}));
+ EXPECT_TRUE(IsPowerOfTwoOrZero(uint16_t{2}));
+ EXPECT_FALSE(IsPowerOfTwoOrZero(uint16_t{3}));
+ EXPECT_TRUE(IsPowerOfTwoOrZero(uint16_t{16}));
+ EXPECT_FALSE(IsPowerOfTwoOrZero(uint16_t{17}));
+ EXPECT_FALSE(IsPowerOfTwoOrZero((std::numeric_limits<uint16_t>::max)()));
- // ~7-bit URBG
- {
- using constants = FastUniformBitsURBGConstants<UrngOddbits>;
- static_assert(constants::kPowerOfTwo == false,
- "constants::kPowerOfTwo == false");
- static_assert(constants::kRange == 0xfe, "constants::kRange == 0xfe");
- static_assert(constants::kRangeBits == 7, "constants::kRangeBits == 7");
- static_assert(constants::kRangeMask == 0x7f,
- "constants::kRangeMask == 0x7f");
- }
+ EXPECT_TRUE(IsPowerOfTwoOrZero(uint32_t{0}));
+ EXPECT_TRUE(IsPowerOfTwoOrZero(uint32_t{1}));
+ EXPECT_TRUE(IsPowerOfTwoOrZero(uint32_t{2}));
+ EXPECT_FALSE(IsPowerOfTwoOrZero(uint32_t{3}));
+ EXPECT_TRUE(IsPowerOfTwoOrZero(uint32_t{32}));
+ EXPECT_FALSE(IsPowerOfTwoOrZero(uint32_t{17}));
+ EXPECT_FALSE(IsPowerOfTwoOrZero((std::numeric_limits<uint32_t>::max)()));
+
+ EXPECT_TRUE(IsPowerOfTwoOrZero(uint64_t{0}));
+ EXPECT_TRUE(IsPowerOfTwoOrZero(uint64_t{1}));
+ EXPECT_TRUE(IsPowerOfTwoOrZero(uint64_t{2}));
+ EXPECT_FALSE(IsPowerOfTwoOrZero(uint64_t{3}));
+ EXPECT_TRUE(IsPowerOfTwoOrZero(uint64_t{64}));
+ EXPECT_FALSE(IsPowerOfTwoOrZero(uint64_t{17}));
+ EXPECT_FALSE(IsPowerOfTwoOrZero((std::numeric_limits<uint64_t>::max)()));
+}
+
+TEST(FastUniformBitsTest, IntegerLog2) {
+ EXPECT_EQ(IntegerLog2(uint16_t{0}), 0);
+ EXPECT_EQ(IntegerLog2(uint16_t{1}), 0);
+ EXPECT_EQ(IntegerLog2(uint16_t{2}), 1);
+ EXPECT_EQ(IntegerLog2(uint16_t{3}), 1);
+ EXPECT_EQ(IntegerLog2(uint16_t{4}), 2);
+ EXPECT_EQ(IntegerLog2(uint16_t{5}), 2);
+ EXPECT_EQ(IntegerLog2(std::numeric_limits<uint64_t>::max()), 63);
+}
+
+TEST(FastUniformBitsTest, RangeSize) {
+ EXPECT_EQ((RangeSize<FakeUrbg<uint8_t, 0, 3>>()), 4);
+ EXPECT_EQ((RangeSize<FakeUrbg<uint8_t, 2, 2>>()), 1);
+ EXPECT_EQ((RangeSize<FakeUrbg<uint8_t, 2, 5>>()), 4);
+ EXPECT_EQ((RangeSize<FakeUrbg<uint8_t, 2, 6>>()), 5);
+ EXPECT_EQ((RangeSize<FakeUrbg<uint8_t, 2, 10>>()), 9);
+ EXPECT_EQ(
+ (RangeSize<FakeUrbg<uint8_t, 0, std::numeric_limits<uint8_t>::max()>>()),
+ 0);
+
+ EXPECT_EQ((RangeSize<FakeUrbg<uint16_t, 0, 3>>()), 4);
+ EXPECT_EQ((RangeSize<FakeUrbg<uint16_t, 2, 2>>()), 1);
+ EXPECT_EQ((RangeSize<FakeUrbg<uint16_t, 2, 5>>()), 4);
+ EXPECT_EQ((RangeSize<FakeUrbg<uint16_t, 2, 6>>()), 5);
+ EXPECT_EQ((RangeSize<FakeUrbg<uint16_t, 1000, 1017>>()), 18);
+ EXPECT_EQ((RangeSize<
+ FakeUrbg<uint16_t, 0, std::numeric_limits<uint16_t>::max()>>()),
+ 0);
+
+ EXPECT_EQ((RangeSize<FakeUrbg<uint32_t, 0, 3>>()), 4);
+ EXPECT_EQ((RangeSize<FakeUrbg<uint32_t, 2, 2>>()), 1);
+ EXPECT_EQ((RangeSize<FakeUrbg<uint32_t, 2, 5>>()), 4);
+ EXPECT_EQ((RangeSize<FakeUrbg<uint32_t, 2, 6>>()), 5);
+ EXPECT_EQ((RangeSize<FakeUrbg<uint32_t, 1000, 1017>>()), 18);
+ EXPECT_EQ((RangeSize<FakeUrbg<uint32_t, 0, 0xffffffff>>()), 0);
+ EXPECT_EQ((RangeSize<FakeUrbg<uint32_t, 1, 0xffffffff>>()), 0xffffffff);
+ EXPECT_EQ((RangeSize<FakeUrbg<uint32_t, 1, 0xfffffffe>>()), 0xfffffffe);
+ EXPECT_EQ((RangeSize<FakeUrbg<uint32_t, 2, 0xfffffffe>>()), 0xfffffffd);
+ EXPECT_EQ((RangeSize<
+ FakeUrbg<uint32_t, 0, std::numeric_limits<uint32_t>::max()>>()),
+ 0);
+
+ EXPECT_EQ((RangeSize<FakeUrbg<uint64_t, 0, 3>>()), 4);
+ EXPECT_EQ((RangeSize<FakeUrbg<uint64_t, 2, 2>>()), 1);
+ EXPECT_EQ((RangeSize<FakeUrbg<uint64_t, 2, 5>>()), 4);
+ EXPECT_EQ((RangeSize<FakeUrbg<uint64_t, 2, 6>>()), 5);
+ EXPECT_EQ((RangeSize<FakeUrbg<uint64_t, 1000, 1017>>()), 18);
+ EXPECT_EQ((RangeSize<FakeUrbg<uint64_t, 0, 0xffffffff>>()), 0x100000000ull);
+ EXPECT_EQ((RangeSize<FakeUrbg<uint64_t, 1, 0xffffffff>>()), 0xffffffffull);
+ EXPECT_EQ((RangeSize<FakeUrbg<uint64_t, 1, 0xfffffffe>>()), 0xfffffffeull);
+ EXPECT_EQ((RangeSize<FakeUrbg<uint64_t, 2, 0xfffffffe>>()), 0xfffffffdull);
+ EXPECT_EQ((RangeSize<FakeUrbg<uint64_t, 0, 0xffffffffffffffffull>>()), 0ull);
+ EXPECT_EQ((RangeSize<FakeUrbg<uint64_t, 1, 0xffffffffffffffffull>>()),
+ 0xffffffffffffffffull);
+ EXPECT_EQ((RangeSize<FakeUrbg<uint64_t, 1, 0xfffffffffffffffeull>>()),
+ 0xfffffffffffffffeull);
+ EXPECT_EQ((RangeSize<FakeUrbg<uint64_t, 2, 0xfffffffffffffffeull>>()),
+ 0xfffffffffffffffdull);
+ EXPECT_EQ((RangeSize<
+ FakeUrbg<uint64_t, 0, std::numeric_limits<uint64_t>::max()>>()),
+ 0);
+}
+
+TEST(FastUniformBitsTest, PowerOfTwoSubRangeSize) {
+ EXPECT_EQ((PowerOfTwoSubRangeSize<FakeUrbg<uint8_t, 0, 3>>()), 4);
+ EXPECT_EQ((PowerOfTwoSubRangeSize<FakeUrbg<uint8_t, 2, 2>>()), 1);
+ EXPECT_EQ((PowerOfTwoSubRangeSize<FakeUrbg<uint8_t, 2, 5>>()), 4);
+ EXPECT_EQ((PowerOfTwoSubRangeSize<FakeUrbg<uint8_t, 2, 6>>()), 4);
+ EXPECT_EQ((PowerOfTwoSubRangeSize<FakeUrbg<uint8_t, 2, 10>>()), 8);
+ EXPECT_EQ((PowerOfTwoSubRangeSize<
+ FakeUrbg<uint8_t, 0, std::numeric_limits<uint8_t>::max()>>()),
+ 0);
+
+ EXPECT_EQ((PowerOfTwoSubRangeSize<FakeUrbg<uint16_t, 0, 3>>()), 4);
+ EXPECT_EQ((PowerOfTwoSubRangeSize<FakeUrbg<uint16_t, 2, 2>>()), 1);
+ EXPECT_EQ((PowerOfTwoSubRangeSize<FakeUrbg<uint16_t, 2, 5>>()), 4);
+ EXPECT_EQ((PowerOfTwoSubRangeSize<FakeUrbg<uint16_t, 2, 6>>()), 4);
+ EXPECT_EQ((PowerOfTwoSubRangeSize<FakeUrbg<uint16_t, 1000, 1017>>()), 16);
+ EXPECT_EQ((PowerOfTwoSubRangeSize<
+ FakeUrbg<uint16_t, 0, std::numeric_limits<uint16_t>::max()>>()),
+ 0);
+
+ EXPECT_EQ((PowerOfTwoSubRangeSize<FakeUrbg<uint32_t, 0, 3>>()), 4);
+ EXPECT_EQ((PowerOfTwoSubRangeSize<FakeUrbg<uint32_t, 2, 2>>()), 1);
+ EXPECT_EQ((PowerOfTwoSubRangeSize<FakeUrbg<uint32_t, 2, 5>>()), 4);
+ EXPECT_EQ((PowerOfTwoSubRangeSize<FakeUrbg<uint32_t, 2, 6>>()), 4);
+ EXPECT_EQ((PowerOfTwoSubRangeSize<FakeUrbg<uint32_t, 1000, 1017>>()), 16);
+ EXPECT_EQ((PowerOfTwoSubRangeSize<FakeUrbg<uint32_t, 0, 0xffffffff>>()), 0);
+ EXPECT_EQ((PowerOfTwoSubRangeSize<FakeUrbg<uint32_t, 1, 0xffffffff>>()),
+ 0x80000000);
+ EXPECT_EQ((PowerOfTwoSubRangeSize<FakeUrbg<uint32_t, 1, 0xfffffffe>>()),
+ 0x80000000);
+ EXPECT_EQ((PowerOfTwoSubRangeSize<
+ FakeUrbg<uint32_t, 0, std::numeric_limits<uint32_t>::max()>>()),
+ 0);
+
+ EXPECT_EQ((PowerOfTwoSubRangeSize<FakeUrbg<uint64_t, 0, 3>>()), 4);
+ EXPECT_EQ((PowerOfTwoSubRangeSize<FakeUrbg<uint64_t, 2, 2>>()), 1);
+ EXPECT_EQ((PowerOfTwoSubRangeSize<FakeUrbg<uint64_t, 2, 5>>()), 4);
+ EXPECT_EQ((PowerOfTwoSubRangeSize<FakeUrbg<uint64_t, 2, 6>>()), 4);
+ EXPECT_EQ((PowerOfTwoSubRangeSize<FakeUrbg<uint64_t, 1000, 1017>>()), 16);
+ EXPECT_EQ((PowerOfTwoSubRangeSize<FakeUrbg<uint64_t, 0, 0xffffffff>>()),
+ 0x100000000ull);
+ EXPECT_EQ((PowerOfTwoSubRangeSize<FakeUrbg<uint64_t, 1, 0xffffffff>>()),
+ 0x80000000ull);
+ EXPECT_EQ((PowerOfTwoSubRangeSize<FakeUrbg<uint64_t, 1, 0xfffffffe>>()),
+ 0x80000000ull);
+ EXPECT_EQ(
+ (PowerOfTwoSubRangeSize<FakeUrbg<uint64_t, 0, 0xffffffffffffffffull>>()),
+ 0);
+ EXPECT_EQ(
+ (PowerOfTwoSubRangeSize<FakeUrbg<uint64_t, 1, 0xffffffffffffffffull>>()),
+ 0x8000000000000000ull);
+ EXPECT_EQ(
+ (PowerOfTwoSubRangeSize<FakeUrbg<uint64_t, 1, 0xfffffffffffffffeull>>()),
+ 0x8000000000000000ull);
+ EXPECT_EQ((PowerOfTwoSubRangeSize<
+ FakeUrbg<uint64_t, 0, std::numeric_limits<uint64_t>::max()>>()),
+ 0);
}
TEST(FastUniformBitsTest, Urng4_VariousOutputs) {
// Tests that how values are composed; the single-bit deltas should be spread
// across each invocation.
Urng4bits urng4;
+ Urng31bits urng31;
Urng32bits urng32;
// 8-bit types
{
- absl::random_internal::FastUniformBits<uint8_t> fast8;
+ FastUniformBits<uint8_t> fast8;
EXPECT_EQ(0x11, fast8(urng4));
+ EXPECT_EQ(0x2, fast8(urng31));
EXPECT_EQ(0x1, fast8(urng32));
}
// 16-bit types
{
- absl::random_internal::FastUniformBits<uint16_t> fast16;
+ FastUniformBits<uint16_t> fast16;
EXPECT_EQ(0x1111, fast16(urng4));
- EXPECT_EQ(0x1, fast16(urng32));
+ EXPECT_EQ(0xf02, fast16(urng31));
+ EXPECT_EQ(0xf01, fast16(urng32));
}
// 32-bit types
{
- absl::random_internal::FastUniformBits<uint32_t> fast32;
+ FastUniformBits<uint32_t> fast32;
EXPECT_EQ(0x11111111, fast32(urng4));
- EXPECT_EQ(0x1, fast32(urng32));
+ EXPECT_EQ(0x0f020f02, fast32(urng31));
+ EXPECT_EQ(0x74010f01, fast32(urng32));
}
// 64-bit types
{
- absl::random_internal::FastUniformBits<uint64_t> fast64;
+ FastUniformBits<uint64_t> fast64;
EXPECT_EQ(0x1111111111111111, fast64(urng4));
- EXPECT_EQ(0x0000000100000001, fast64(urng32));
+ EXPECT_EQ(0x387811c3c0870f02, fast64(urng31));
+ EXPECT_EQ(0x74010f0174010f01, fast64(urng32));
}
}
+TEST(FastUniformBitsTest, URBG32bitRegression) {
+ // Validate with deterministic 32-bit std::minstd_rand
+ // to ensure that operator() performs as expected.
+ std::minstd_rand gen(1);
+ FastUniformBits<uint64_t> fast64;
+
+ EXPECT_EQ(0x05e47095f847c122ull, fast64(gen));
+ EXPECT_EQ(0x8f82c1ba30b64d22ull, fast64(gen));
+ EXPECT_EQ(0x3b971a3558155039ull, fast64(gen));
+}
+
} // namespace
+} // namespace random_internal
+} // namespace absl
diff --git a/absl/strings/str_join.h b/absl/strings/str_join.h
index 7345b962..4772f5d1 100644
--- a/absl/strings/str_join.h
+++ b/absl/strings/str_join.h
@@ -254,7 +254,7 @@ std::string StrJoin(const Range& range, absl::string_view separator,
template <typename T, typename Formatter>
std::string StrJoin(std::initializer_list<T> il, absl::string_view separator,
- Formatter&& fmt) {
+ Formatter&& fmt) {
return strings_internal::JoinRange(il, separator, fmt);
}
@@ -275,7 +275,8 @@ std::string StrJoin(const Range& range, absl::string_view separator) {
}
template <typename T>
-std::string StrJoin(std::initializer_list<T> il, absl::string_view separator) {
+std::string StrJoin(std::initializer_list<T> il,
+ absl::string_view separator) {
return strings_internal::JoinRange(il, separator);
}
diff --git a/absl/synchronization/internal/create_thread_identity.cc b/absl/synchronization/internal/create_thread_identity.cc
index 6e93605d..ce3676a8 100644
--- a/absl/synchronization/internal/create_thread_identity.cc
+++ b/absl/synchronization/internal/create_thread_identity.cc
@@ -31,7 +31,8 @@ namespace synchronization_internal {
// ThreadIdentity storage is persistent, we maintain a free-list of previously
// released ThreadIdentity objects.
-static base_internal::SpinLock freelist_lock(base_internal::kLinkerInitialized);
+static base_internal::SpinLock freelist_lock(
+ base_internal::kLinkerInitialized);
static base_internal::ThreadIdentity* thread_identity_freelist;
// A per-thread destructor for reclaiming associated ThreadIdentity objects.
diff --git a/absl/time/time.h b/absl/time/time.h
index 05347805..e236870b 100644
--- a/absl/time/time.h
+++ b/absl/time/time.h
@@ -179,6 +179,7 @@ class Duration {
Duration& operator%=(Duration rhs);
// Overloads that forward to either the int64_t or double overloads above.
+ // Integer operands must be representable as int64_t.
template <typename T>
Duration& operator*=(T r) {
int64_t x = r;
@@ -221,6 +222,7 @@ inline Duration operator+(Duration lhs, Duration rhs) { return lhs += rhs; }
inline Duration operator-(Duration lhs, Duration rhs) { return lhs -= rhs; }
// Multiplicative Operators
+// Integer operands must be representable as int64_t.
template <typename T>
Duration operator*(Duration lhs, T rhs) {
return lhs *= rhs;
@@ -375,7 +377,8 @@ constexpr Duration InfiniteDuration();
// Hours()
//
// Factory functions for constructing `Duration` values from an integral number
-// of the unit indicated by the factory function's name.
+// of the unit indicated by the factory function's name. The number must be
+// representable as int64_t.
//
// Note: no "Days()" factory function exists because "a day" is ambiguous.
// Civil days are not always 24 hours long, and a 24-hour duration often does