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-rw-r--r--absl/flags/flag.h8
-rw-r--r--absl/strings/BUILD.bazel12
-rw-r--r--absl/strings/CMakeLists.txt13
-rw-r--r--absl/strings/cord.cc20
-rw-r--r--absl/strings/cord.h28
-rw-r--r--absl/strings/cord_test.cc43
-rw-r--r--absl/strings/internal/cord_internal.h41
-rw-r--r--absl/strings/internal/cord_internal_test.cc116
-rw-r--r--absl/strings/internal/cord_rep_btree.cc227
-rw-r--r--absl/strings/internal/cord_rep_btree.h95
-rw-r--r--absl/strings/internal/cord_rep_btree_test.cc136
-rw-r--r--absl/strings/internal/cord_rep_ring.cc20
-rw-r--r--absl/strings/internal/cord_rep_ring.h4
-rw-r--r--absl/strings/internal/cord_rep_test_util.h35
-rw-r--r--absl/strings/internal/cordz_update_tracker.h2
-rw-r--r--absl/strings/internal/cordz_update_tracker_test.cc2
-rw-r--r--absl/strings/numbers.h34
-rw-r--r--absl/strings/numbers_test.cc143
-rw-r--r--absl/strings/str_split_test.cc8
-rw-r--r--absl/strings/substitute.cc3
20 files changed, 890 insertions, 100 deletions
diff --git a/absl/flags/flag.h b/absl/flags/flag.h
index 1a7e4d4d..a724ccc9 100644
--- a/absl/flags/flag.h
+++ b/absl/flags/flag.h
@@ -241,8 +241,8 @@ ABSL_NAMESPACE_END
/* default value argument. That keeps temporaries alive */ \
/* long enough for NonConst to work correctly. */ \
static constexpr absl::string_view Value( \
- absl::string_view v = ABSL_FLAG_IMPL_FLAGHELP(txt)) { \
- return v; \
+ absl::string_view absl_flag_help = ABSL_FLAG_IMPL_FLAGHELP(txt)) { \
+ return absl_flag_help; \
} \
static std::string NonConst() { return std::string(Value()); } \
}; \
@@ -254,8 +254,8 @@ ABSL_NAMESPACE_END
#define ABSL_FLAG_IMPL_DECLARE_DEF_VAL_WRAPPER(name, Type, default_value) \
struct AbslFlagDefaultGenFor##name { \
Type value = absl::flags_internal::InitDefaultValue<Type>(default_value); \
- static void Gen(void* p) { \
- new (p) Type(AbslFlagDefaultGenFor##name{}.value); \
+ static void Gen(void* absl_flag_default_loc) { \
+ new (absl_flag_default_loc) Type(AbslFlagDefaultGenFor##name{}.value); \
} \
};
diff --git a/absl/strings/BUILD.bazel b/absl/strings/BUILD.bazel
index c046366c..090fc58a 100644
--- a/absl/strings/BUILD.bazel
+++ b/absl/strings/BUILD.bazel
@@ -306,6 +306,17 @@ cc_library(
)
cc_test(
+ name = "cord_internal_test",
+ srcs = ["internal/cord_internal_test.cc"],
+ copts = ABSL_TEST_COPTS,
+ visibility = ["//visibility:private"],
+ deps = [
+ ":cord_internal",
+ "@com_google_googletest//:gtest_main",
+ ],
+)
+
+cc_test(
name = "cord_rep_btree_test",
size = "medium",
srcs = ["internal/cord_rep_btree_test.cc"],
@@ -684,6 +695,7 @@ cc_test(
"//absl/base:endian",
"//absl/base:raw_logging_internal",
"//absl/container:fixed_array",
+ "//absl/random",
"@com_google_googletest//:gtest_main",
],
)
diff --git a/absl/strings/CMakeLists.txt b/absl/strings/CMakeLists.txt
index 8ad5f9c7..d6801fe6 100644
--- a/absl/strings/CMakeLists.txt
+++ b/absl/strings/CMakeLists.txt
@@ -920,6 +920,7 @@ absl_cc_test(
absl::cordz_test_helpers
absl::core_headers
absl::endian
+ absl::random_random
absl::raw_logging_internal
absl::fixed_array
GTest::gmock_main
@@ -945,6 +946,18 @@ absl_cc_test(
absl_cc_test(
NAME
+ cord_internal_test
+ SRCS
+ "internal/cord_internal_test.cc"
+ COPTS
+ ${ABSL_TEST_COPTS}
+ DEPS
+ absl::cord_internal
+ GTest::gmock_main
+)
+
+absl_cc_test(
+ NAME
cord_rep_btree_test
SRCS
"internal/cord_rep_btree_test.cc"
diff --git a/absl/strings/cord.cc b/absl/strings/cord.cc
index 29af9782..854047ca 100644
--- a/absl/strings/cord.cc
+++ b/absl/strings/cord.cc
@@ -419,7 +419,7 @@ void Cord::InlineRep::PrependTree(CordRep* tree, MethodIdentifier method) {
// written to region and the actual size increase will be written to size.
static inline bool PrepareAppendRegion(CordRep* root, char** region,
size_t* size, size_t max_length) {
- if (root->IsBtree() && root->refcount.IsOne()) {
+ if (root->IsBtree() && root->refcount.IsMutable()) {
Span<char> span = root->btree()->GetAppendBuffer(max_length);
if (!span.empty()) {
*region = span.data();
@@ -430,11 +430,11 @@ static inline bool PrepareAppendRegion(CordRep* root, char** region,
// Search down the right-hand path for a non-full FLAT node.
CordRep* dst = root;
- while (dst->IsConcat() && dst->refcount.IsOne()) {
+ while (dst->IsConcat() && dst->refcount.IsMutable()) {
dst = dst->concat()->right;
}
- if (!dst->IsFlat() || !dst->refcount.IsOne()) {
+ if (!dst->IsFlat() || !dst->refcount.IsMutable()) {
*region = nullptr;
*size = 0;
return false;
@@ -649,7 +649,7 @@ Cord& Cord::operator=(absl::string_view src) {
if (tree != nullptr) {
CordzUpdateScope scope(contents_.cordz_info(), method);
if (tree->IsFlat() && tree->flat()->Capacity() >= length &&
- tree->refcount.IsOne()) {
+ tree->refcount.IsMutable()) {
// Copy in place if the existing FLAT node is reusable.
memmove(tree->flat()->Data(), data, length);
tree->length = length;
@@ -819,7 +819,7 @@ void Cord::Prepend(const Cord& src) {
return Prepend(src_contents);
}
-void Cord::Prepend(absl::string_view src) {
+void Cord::PrependArray(absl::string_view src, MethodIdentifier method) {
if (src.empty()) return; // memcpy(_, nullptr, 0) is undefined.
if (!contents_.is_tree()) {
size_t cur_size = contents_.inline_size();
@@ -834,7 +834,7 @@ void Cord::Prepend(absl::string_view src) {
}
}
CordRep* rep = NewTree(src.data(), src.size(), 0);
- contents_.PrependTree(rep, CordzUpdateTracker::kPrependString);
+ contents_.PrependTree(rep, method);
}
template <typename T, Cord::EnableIfString<T>>
@@ -894,7 +894,7 @@ static CordRep* RemoveSuffixFrom(CordRep* node, size_t n) {
if (n >= node->length) return nullptr;
if (n == 0) return CordRep::Ref(node);
absl::InlinedVector<CordRep*, kInlinedVectorSize> lhs_stack;
- bool inplace_ok = node->refcount.IsOne();
+ bool inplace_ok = node->refcount.IsMutable();
while (node->IsConcat()) {
assert(n <= node->length);
@@ -907,7 +907,7 @@ static CordRep* RemoveSuffixFrom(CordRep* node, size_t n) {
n -= node->concat()->right->length;
node = node->concat()->left;
}
- inplace_ok = inplace_ok && node->refcount.IsOne();
+ inplace_ok = inplace_ok && node->refcount.IsMutable();
}
assert(n <= node->length);
@@ -968,9 +968,7 @@ void Cord::RemoveSuffix(size_t n) {
auto constexpr method = CordzUpdateTracker::kRemoveSuffix;
CordzUpdateScope scope(contents_.cordz_info(), method);
if (tree->IsBtree()) {
- CordRep* old = tree;
- tree = tree->btree()->SubTree(0, tree->length - n);
- CordRep::Unref(old);
+ tree = CordRepBtree::RemoveSuffix(tree->btree(), n);
} else {
CordRep* newrep = RemoveSuffixFrom(tree, n);
CordRep::Unref(tree);
diff --git a/absl/strings/cord.h b/absl/strings/cord.h
index 175d7b90..f0a19914 100644
--- a/absl/strings/cord.h
+++ b/absl/strings/cord.h
@@ -460,6 +460,16 @@ class Cord {
// `Cord::chunk_begin()` and `Cord::chunk_end()`.
class ChunkRange {
public:
+ // Fulfill minimum c++ container requirements [container.requirements]
+ // Theses (partial) container type definitions allow ChunkRange to be used
+ // in various utilities expecting a subset of [container.requirements].
+ // For example, the below enables using `::testing::ElementsAre(...)`
+ using value_type = absl::string_view;
+ using reference = value_type&;
+ using const_reference = const value_type&;
+ using iterator = ChunkIterator;
+ using const_iterator = ChunkIterator;
+
explicit ChunkRange(const Cord* cord) : cord_(cord) {}
ChunkIterator begin() const;
@@ -591,6 +601,16 @@ class Cord {
// `Cord::char_begin()` and `Cord::char_end()`.
class CharRange {
public:
+ // Fulfill minimum c++ container requirements [container.requirements]
+ // Theses (partial) container type definitions allow CharRange to be used
+ // in various utilities expecting a subset of [container.requirements].
+ // For example, the below enables using `::testing::ElementsAre(...)`
+ using value_type = char;
+ using reference = value_type&;
+ using const_reference = const value_type&;
+ using iterator = CharIterator;
+ using const_iterator = CharIterator;
+
explicit CharRange(const Cord* cord) : cord_(cord) {}
CharIterator begin() const;
@@ -881,6 +901,10 @@ class Cord {
template <typename C>
void AppendImpl(C&& src);
+ // Prepends the provided data to this instance. `method` contains the public
+ // API method for this action which is tracked for Cordz sampling purposes.
+ void PrependArray(absl::string_view src, MethodIdentifier method);
+
// Assigns the value in 'src' to this instance, 'stealing' its contents.
// Requires src.length() > kMaxBytesToCopy.
Cord& AssignLargeString(std::string&& src);
@@ -1220,6 +1244,10 @@ inline void Cord::Append(absl::string_view src) {
contents_.AppendArray(src, CordzUpdateTracker::kAppendString);
}
+inline void Cord::Prepend(absl::string_view src) {
+ PrependArray(src, CordzUpdateTracker::kPrependString);
+}
+
extern template void Cord::Append(std::string&& src);
extern template void Cord::Prepend(std::string&& src);
diff --git a/absl/strings/cord_test.cc b/absl/strings/cord_test.cc
index 50079b7c..cced9bba 100644
--- a/absl/strings/cord_test.cc
+++ b/absl/strings/cord_test.cc
@@ -34,6 +34,7 @@
#include "absl/base/internal/raw_logging.h"
#include "absl/base/macros.h"
#include "absl/container/fixed_array.h"
+#include "absl/random/random.h"
#include "absl/strings/cord_test_helpers.h"
#include "absl/strings/cordz_test_helpers.h"
#include "absl/strings/str_cat.h"
@@ -1833,6 +1834,48 @@ TEST_P(CordTest, Hardening) {
EXPECT_DEATH_IF_SUPPORTED(++cord.chunk_end(), "");
}
+// This test mimics a specific (and rare) application repeatedly splitting a
+// cord, inserting (overwriting) a string value, and composing a new cord from
+// the three pieces. This is hostile towards a Btree implementation: A split of
+// a node at any level is likely to have the right-most edge of the left split,
+// and the left-most edge of the right split shared. For example, splitting a
+// leaf node with 6 edges will result likely in a 1-6, 2-5, 3-4, etc. split,
+// sharing the 'split node'. When recomposing such nodes, we 'injected' an edge
+// in that node. As this happens with some probability on each level of the
+// tree, this will quickly grow the tree until it reaches maximum height.
+TEST_P(CordTest, BtreeHostileSplitInsertJoin) {
+ absl::BitGen bitgen;
+
+ // Start with about 1GB of data
+ std::string data(1 << 10, 'x');
+ absl::Cord buffer(data);
+ absl::Cord cord;
+ for (int i = 0; i < 1000000; ++i) {
+ cord.Append(buffer);
+ }
+
+ for (int j = 0; j < 1000; ++j) {
+ size_t offset = absl::Uniform(bitgen, 0u, cord.size());
+ size_t length = absl::Uniform(bitgen, 100u, data.size());
+ if (cord.size() == offset) {
+ cord.Append(absl::string_view(data.data(), length));
+ } else {
+ absl::Cord suffix;
+ if (offset + length < cord.size()) {
+ suffix = cord;
+ suffix.RemovePrefix(offset + length);
+ }
+ if (cord.size() > offset) {
+ cord.RemoveSuffix(cord.size() - offset);
+ }
+ cord.Append(absl::string_view(data.data(), length));
+ if (!suffix.empty()) {
+ cord.Append(suffix);
+ }
+ }
+ }
+}
+
class AfterExitCordTester {
public:
bool Set(absl::Cord* cord, absl::string_view expected) {
diff --git a/absl/strings/internal/cord_internal.h b/absl/strings/internal/cord_internal.h
index 0300ac40..bfe5564e 100644
--- a/absl/strings/internal/cord_internal.h
+++ b/absl/strings/internal/cord_internal.h
@@ -87,6 +87,9 @@ class RefcountAndFlags {
constexpr RefcountAndFlags() : count_{kRefIncrement} {}
struct Immortal {};
explicit constexpr RefcountAndFlags(Immortal) : count_(kImmortalFlag) {}
+ struct WithCrc {};
+ explicit constexpr RefcountAndFlags(WithCrc)
+ : count_(kCrcFlag | kRefIncrement) {}
// Increments the reference count. Imposes no memory ordering.
inline void Increment() {
@@ -122,14 +125,32 @@ class RefcountAndFlags {
return count_.load(std::memory_order_acquire) >> kNumFlags;
}
- // Returns whether the atomic integer is 1.
- // If the reference count is used in the conventional way, a
- // reference count of 1 implies that the current thread owns the
- // reference and no other thread shares it.
- // This call performs the test for a reference count of one, and
- // performs the memory barrier needed for the owning thread
- // to act on the object, knowing that it has exclusive access to the
- // object. Always returns false when the immortal bit is set.
+ // Returns true if the referenced object carries a CRC value.
+ bool HasCrc() const {
+ return (count_.load(std::memory_order_relaxed) & kCrcFlag) != 0;
+ }
+
+ // Returns true iff the atomic integer is 1 and this node does not store
+ // a CRC. When both these conditions are met, the current thread owns
+ // the reference and no other thread shares it, so its contents may be
+ // safely mutated.
+ //
+ // If the referenced item is shared, carries a CRC, or is immortal,
+ // it should not be modified in-place, and this function returns false.
+ //
+ // This call performs the memory barrier needed for the owning thread
+ // to act on the object, so that if it returns true, it may safely
+ // assume exclusive access to the object.
+ inline bool IsMutable() {
+ return (count_.load(std::memory_order_acquire)) == kRefIncrement;
+ }
+
+ // Returns whether the atomic integer is 1. Similar to IsMutable(),
+ // but does not check for a stored CRC. (An unshared node with a CRC is not
+ // mutable, because changing its data would invalidate the CRC.)
+ //
+ // When this returns true, there are no other references, and data sinks
+ // may safely adopt the children of the CordRep.
inline bool IsOne() {
return (count_.load(std::memory_order_acquire) & kRefcountMask) ==
kRefIncrement;
@@ -149,14 +170,14 @@ class RefcountAndFlags {
kNumFlags = 2,
kImmortalFlag = 0x1,
- kReservedFlag = 0x2,
+ kCrcFlag = 0x2,
kRefIncrement = (1 << kNumFlags),
// Bitmask to use when checking refcount by equality. This masks out
// all flags except kImmortalFlag, which is part of the refcount for
// purposes of equality. (A refcount of 0 or 1 does not count as 0 or 1
// if the immortal bit is set.)
- kRefcountMask = ~kReservedFlag,
+ kRefcountMask = ~kCrcFlag,
};
std::atomic<int32_t> count_;
diff --git a/absl/strings/internal/cord_internal_test.cc b/absl/strings/internal/cord_internal_test.cc
new file mode 100644
index 00000000..0758dfef
--- /dev/null
+++ b/absl/strings/internal/cord_internal_test.cc
@@ -0,0 +1,116 @@
+// Copyright 2021 The Abseil Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// https://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include "absl/strings/internal/cord_internal.h"
+
+#include "gmock/gmock.h"
+
+namespace absl {
+ABSL_NAMESPACE_BEGIN
+namespace cord_internal {
+
+TEST(RefcountAndFlags, NormalRefcount) {
+ for (bool expect_high_refcount : {false, true}) {
+ SCOPED_TRACE(expect_high_refcount);
+ RefcountAndFlags refcount;
+ // count = 1
+
+ EXPECT_FALSE(refcount.HasCrc());
+ EXPECT_TRUE(refcount.IsMutable());
+ EXPECT_TRUE(refcount.IsOne());
+
+ refcount.Increment();
+ // count = 2
+
+ EXPECT_FALSE(refcount.HasCrc());
+ EXPECT_FALSE(refcount.IsMutable());
+ EXPECT_FALSE(refcount.IsOne());
+
+ // Decrementing should return true, since a reference is outstanding.
+ if (expect_high_refcount) {
+ EXPECT_TRUE(refcount.DecrementExpectHighRefcount());
+ } else {
+ EXPECT_TRUE(refcount.Decrement());
+ }
+ // count = 1
+
+ EXPECT_FALSE(refcount.HasCrc());
+ EXPECT_TRUE(refcount.IsMutable());
+ EXPECT_TRUE(refcount.IsOne());
+
+ // One more decremnt will return false, as no references remain.
+ if (expect_high_refcount) {
+ EXPECT_FALSE(refcount.DecrementExpectHighRefcount());
+ } else {
+ EXPECT_FALSE(refcount.Decrement());
+ }
+ }
+}
+
+TEST(RefcountAndFlags, CrcRefcount) {
+ for (bool expect_high_refcount : {false, true}) {
+ SCOPED_TRACE(expect_high_refcount);
+ RefcountAndFlags refcount(RefcountAndFlags::WithCrc{});
+ // count = 1
+
+ // A CRC-carrying node is never mutable, but can be unshared
+ EXPECT_TRUE(refcount.HasCrc());
+ EXPECT_FALSE(refcount.IsMutable());
+ EXPECT_TRUE(refcount.IsOne());
+
+ refcount.Increment();
+ // count = 2
+
+ EXPECT_TRUE(refcount.HasCrc());
+ EXPECT_FALSE(refcount.IsMutable());
+ EXPECT_FALSE(refcount.IsOne());
+
+ // Decrementing should return true, since a reference is outstanding.
+ if (expect_high_refcount) {
+ EXPECT_TRUE(refcount.DecrementExpectHighRefcount());
+ } else {
+ EXPECT_TRUE(refcount.Decrement());
+ }
+ // count = 1
+
+ EXPECT_TRUE(refcount.HasCrc());
+ EXPECT_FALSE(refcount.IsMutable());
+ EXPECT_TRUE(refcount.IsOne());
+
+ // One more decremnt will return false, as no references remain.
+ if (expect_high_refcount) {
+ EXPECT_FALSE(refcount.DecrementExpectHighRefcount());
+ } else {
+ EXPECT_FALSE(refcount.Decrement());
+ }
+ }
+}
+
+TEST(RefcountAndFlags, ImmortalRefcount) {
+ RefcountAndFlags immortal_refcount(RefcountAndFlags::Immortal{});
+
+ for (int i = 0; i < 100; ++i) {
+ // An immortal refcount is never unshared, and decrementing never causes
+ // a collection.
+ EXPECT_FALSE(immortal_refcount.HasCrc());
+ EXPECT_FALSE(immortal_refcount.IsMutable());
+ EXPECT_FALSE(immortal_refcount.IsOne());
+ EXPECT_TRUE(immortal_refcount.Decrement());
+ EXPECT_TRUE(immortal_refcount.DecrementExpectHighRefcount());
+ }
+}
+
+} // namespace cord_internal
+ABSL_NAMESPACE_END
+} // namespace absl
diff --git a/absl/strings/internal/cord_rep_btree.cc b/absl/strings/internal/cord_rep_btree.cc
index 6d53ab61..4404f33a 100644
--- a/absl/strings/internal/cord_rep_btree.cc
+++ b/absl/strings/internal/cord_rep_btree.cc
@@ -140,6 +140,26 @@ inline CordRep* MakeSubstring(CordRep* rep, size_t offset) {
return CreateSubstring(rep, offset, rep->length - offset);
}
+// Resizes `edge` to the provided `length`. Adopts a reference on `edge`.
+// This method directly returns `edge` if `length` equals `edge->length`.
+// If `is_mutable` is set to true, this function may return `edge` with
+// `edge->length` set to the new length depending on the type and size of
+// `edge`. Otherwise, this function returns a new CordRepSubstring value.
+// Requires `length > 0 && length <= edge->length`.
+CordRep* ResizeEdge(CordRep* edge, size_t length, bool is_mutable) {
+ assert(length > 0);
+ assert(length <= edge->length);
+ assert(CordRepBtree::IsDataEdge(edge));
+ if (length >= edge->length) return edge;
+
+ if (is_mutable && (edge->tag >= FLAT || edge->tag == SUBSTRING)) {
+ edge->length = length;
+ return edge;
+ }
+
+ return CreateSubstring(edge, 0, length);
+}
+
template <EdgeType edge_type>
inline absl::string_view Consume(absl::string_view s, size_t n) {
return edge_type == kBack ? s.substr(n) : s.substr(0, s.size() - n);
@@ -196,8 +216,8 @@ void DeleteLeafEdge(CordRep* rep) {
// propagate node changes up the stack.
template <EdgeType edge_type>
struct StackOperations {
- // Returns true if the node at 'depth' is not shared, i.e. has a refcount
- // of one and all of its parent nodes have a refcount of one.
+ // Returns true if the node at 'depth' is mutable, i.e. has a refcount
+ // of one, carries no CRC, and all of its parent nodes have a refcount of one.
inline bool owned(int depth) const { return depth < share_depth; }
// Returns the node at 'depth'.
@@ -208,11 +228,11 @@ struct StackOperations {
inline CordRepBtree* BuildStack(CordRepBtree* tree, int depth) {
assert(depth <= tree->height());
int current_depth = 0;
- while (current_depth < depth && tree->refcount.IsOne()) {
+ while (current_depth < depth && tree->refcount.IsMutable()) {
stack[current_depth++] = tree;
tree = tree->Edge(edge_type)->btree();
}
- share_depth = current_depth + (tree->refcount.IsOne() ? 1 : 0);
+ share_depth = current_depth + (tree->refcount.IsMutable() ? 1 : 0);
while (current_depth < depth) {
stack[current_depth++] = tree;
tree = tree->Edge(edge_type)->btree();
@@ -221,17 +241,17 @@ struct StackOperations {
}
// Builds a stack with the invariant that all nodes are private owned / not
- // shared. This is used in iterative updates where a previous propagation
- // guaranteed all nodes are owned / private.
+ // shared and carry no CRC data. This is used in iterative updates where a
+ // previous propagation guaranteed all nodes have this property.
inline void BuildOwnedStack(CordRepBtree* tree, int height) {
assert(height <= CordRepBtree::kMaxHeight);
int depth = 0;
while (depth < height) {
- assert(tree->refcount.IsOne());
+ assert(tree->refcount.IsMutable());
stack[depth++] = tree;
tree = tree->Edge(edge_type)->btree();
}
- assert(tree->refcount.IsOne());
+ assert(tree->refcount.IsMutable());
share_depth = depth + 1;
}
@@ -240,11 +260,14 @@ struct StackOperations {
static inline CordRepBtree* Finalize(CordRepBtree* tree, OpResult result) {
switch (result.action) {
case CordRepBtree::kPopped:
- if (ABSL_PREDICT_FALSE(tree->height() >= CordRepBtree::kMaxHeight)) {
- ABSL_RAW_LOG(FATAL, "Max height exceeded");
- }
- return edge_type == kBack ? CordRepBtree::New(tree, result.tree)
+ tree = edge_type == kBack ? CordRepBtree::New(tree, result.tree)
: CordRepBtree::New(result.tree, tree);
+ if (ABSL_PREDICT_FALSE(tree->height() > CordRepBtree::kMaxHeight)) {
+ tree = CordRepBtree::Rebuild(tree);
+ ABSL_RAW_CHECK(tree->height() <= CordRepBtree::kMaxHeight,
+ "Max height exceeded");
+ }
+ return tree;
case CordRepBtree::kCopied:
CordRep::Unref(tree);
ABSL_FALLTHROUGH_INTENDED;
@@ -313,12 +336,12 @@ struct StackOperations {
return Unwind</*propagate=*/true>(tree, depth, length, result);
}
- // `share_depth` contains the depth at which the nodes in the stack become
- // shared. I.e., if the top most level is shared (i.e.: `!refcount.IsOne()`),
- // then `share_depth` is 0. If the 2nd node is shared (and implicitly all
- // nodes below that) then `share_depth` is 1, etc. A `share_depth` greater
- // than the depth of the stack indicates that none of the nodes in the stack
- // are shared.
+ // `share_depth` contains the depth at which the nodes in the stack cannot
+ // be mutated. I.e., if the top most level is shared (i.e.:
+ // `!refcount.IsMutable()`), then `share_depth` is 0. If the 2nd node
+ // is shared (and implicitly all nodes below that) then `share_depth` is 1,
+ // etc. A `share_depth` greater than the depth of the stack indicates that
+ // none of the nodes in the stack are shared.
int share_depth;
NodeStack stack;
@@ -692,7 +715,7 @@ CopyResult CordRepBtree::CopySuffix(size_t offset) {
return result;
}
-CopyResult CordRepBtree::CopyPrefix(size_t n) {
+CopyResult CordRepBtree::CopyPrefix(size_t n, bool allow_folding) {
assert(n > 0);
assert(n <= this->length);
@@ -704,10 +727,12 @@ CopyResult CordRepBtree::CopyPrefix(size_t n) {
int height = this->height();
CordRepBtree* node = this;
CordRep* front = node->Edge(kFront);
- while (front->length >= n) {
- if (--height < 0) return {MakeSubstring(CordRep::Ref(front), 0, n), -1};
- node = front->btree();
- front = node->Edge(kFront);
+ if (allow_folding) {
+ while (front->length >= n) {
+ if (--height < 0) return {MakeSubstring(CordRep::Ref(front), 0, n), -1};
+ node = front->btree();
+ front = node->Edge(kFront);
+ }
}
if (node->length == n) return {CordRep::Ref(node), height};
@@ -746,6 +771,97 @@ CopyResult CordRepBtree::CopyPrefix(size_t n) {
return result;
}
+CordRep* CordRepBtree::ExtractFront(CordRepBtree* tree) {
+ CordRep* front = tree->Edge(tree->begin());
+ if (tree->refcount.IsMutable()) {
+ Unref(tree->Edges(tree->begin() + 1, tree->end()));
+ CordRepBtree::Delete(tree);
+ } else {
+ CordRep::Ref(front);
+ CordRep::Unref(tree);
+ }
+ return front;
+}
+
+CordRepBtree* CordRepBtree::ConsumeBeginTo(CordRepBtree* tree, size_t end,
+ size_t new_length) {
+ assert(end <= tree->end());
+ if (tree->refcount.IsMutable()) {
+ Unref(tree->Edges(end, tree->end()));
+ tree->set_end(end);
+ tree->length = new_length;
+ } else {
+ CordRepBtree* old = tree;
+ tree = tree->CopyBeginTo(end, new_length);
+ CordRep::Unref(old);
+ }
+ return tree;
+}
+
+CordRep* CordRepBtree::RemoveSuffix(CordRepBtree* tree, size_t n) {
+ // Check input and deal with trivial cases 'Remove all/none'
+ assert(tree != nullptr);
+ assert(n <= tree->length);
+ const size_t len = tree->length;
+ if (ABSL_PREDICT_FALSE(n == 0)) {
+ return tree;
+ }
+ if (ABSL_PREDICT_FALSE(n >= len)) {
+ CordRepBtree::Unref(tree);
+ return nullptr;
+ }
+
+ size_t length = len - n;
+ int height = tree->height();
+ bool is_mutable = tree->refcount.IsMutable();
+
+ // Extract all top nodes which are reduced to size = 1
+ Position pos = tree->IndexOfLength(length);
+ while (pos.index == tree->begin()) {
+ CordRep* edge = ExtractFront(tree);
+ is_mutable &= edge->refcount.IsMutable();
+ if (height-- == 0) return ResizeEdge(edge, length, is_mutable);
+ tree = edge->btree();
+ pos = tree->IndexOfLength(length);
+ }
+
+ // Repeat the following sequence traversing down the tree:
+ // - Crop the top node to the 'last remaining edge' adjusting length.
+ // - Set the length for down edges to the partial length in that last edge.
+ // - Repeat this until the last edge is 'included in full'
+ // - If we hit the data edge level, resize and return the last data edge
+ CordRepBtree* top = tree = ConsumeBeginTo(tree, pos.index + 1, length);
+ CordRep* edge = tree->Edge(pos.index);
+ length = pos.n;
+ while (length != edge->length) {
+ // ConsumeBeginTo guarantees `tree` is a clean, privately owned copy.
+ assert(tree->refcount.IsMutable());
+ const bool edge_is_mutable = edge->refcount.IsMutable();
+
+ if (height-- == 0) {
+ tree->edges_[pos.index] = ResizeEdge(edge, length, edge_is_mutable);
+ return AssertValid(top);
+ }
+
+ if (!edge_is_mutable) {
+ // We can't 'in place' remove any suffixes down this edge.
+ // Replace this edge with a prefix copy instead.
+ tree->edges_[pos.index] = edge->btree()->CopyPrefix(length, false).edge;
+ CordRep::Unref(edge);
+ return AssertValid(top);
+ }
+
+ // Move down one level, rinse repeat.
+ tree = edge->btree();
+ pos = tree->IndexOfLength(length);
+ tree = ConsumeBeginTo(edge->btree(), pos.index + 1, length);
+ edge = tree->Edge(pos.index);
+ length = pos.n;
+ }
+
+ return AssertValid(top);
+}
+
CordRep* CordRepBtree::SubTree(size_t offset, size_t n) {
assert(n <= this->length);
assert(offset <= this->length - n);
@@ -857,7 +973,7 @@ char CordRepBtree::GetCharacter(size_t offset) const {
Span<char> CordRepBtree::GetAppendBufferSlow(size_t size) {
// The inlined version in `GetAppendBuffer()` deals with all heights <= 3.
assert(height() >= 4);
- assert(refcount.IsOne());
+ assert(refcount.IsMutable());
// Build a stack of nodes we may potentially need to update if we find a
// non-shared FLAT with capacity at the leaf level.
@@ -866,13 +982,13 @@ Span<char> CordRepBtree::GetAppendBufferSlow(size_t size) {
CordRepBtree* stack[kMaxDepth];
for (int i = 0; i < depth; ++i) {
node = node->Edge(kBack)->btree();
- if (!node->refcount.IsOne()) return {};
+ if (!node->refcount.IsMutable()) return {};
stack[i] = node;
}
- // Must be a privately owned flat.
+ // Must be a privately owned, mutable flat.
CordRep* const edge = node->Edge(kBack);
- if (!edge->refcount.IsOne() || edge->tag < FLAT) return {};
+ if (!edge->refcount.IsMutable() || edge->tag < FLAT) return {};
// Must have capacity.
const size_t avail = edge->flat()->Capacity() - edge->length;
@@ -950,6 +1066,63 @@ template CordRepBtree* CordRepBtree::AddData<kBack>(CordRepBtree* tree,
absl::string_view data,
size_t extra);
+void CordRepBtree::Rebuild(CordRepBtree** stack, CordRepBtree* tree,
+ bool consume) {
+ bool owned = consume && tree->refcount.IsOne();
+ if (tree->height() == 0) {
+ for (CordRep* edge : tree->Edges()) {
+ if (!owned) edge = CordRep::Ref(edge);
+ size_t height = 0;
+ size_t length = edge->length;
+ CordRepBtree* node = stack[0];
+ OpResult result = node->AddEdge<kBack>(true, edge, length);
+ while (result.action == CordRepBtree::kPopped) {
+ stack[height] = result.tree;
+ if (stack[++height] == nullptr) {
+ result.action = CordRepBtree::kSelf;
+ stack[height] = CordRepBtree::New(node, result.tree);
+ } else {
+ node = stack[height];
+ result = node->AddEdge<kBack>(true, result.tree, length);
+ }
+ }
+ while (stack[++height] != nullptr) {
+ stack[height]->length += length;
+ }
+ }
+ } else {
+ for (CordRep* rep : tree->Edges()) {
+ Rebuild(stack, rep->btree(), owned);
+ }
+ }
+ if (consume) {
+ if (owned) {
+ CordRepBtree::Delete(tree);
+ } else {
+ CordRepBtree::Unref(tree);
+ }
+ }
+}
+
+CordRepBtree* CordRepBtree::Rebuild(CordRepBtree* tree) {
+ // Set up initial stack with empty leaf node.
+ CordRepBtree* node = CordRepBtree::New();
+ CordRepBtree* stack[CordRepBtree::kMaxDepth + 1] = {node};
+
+ // Recursively build the tree, consuming the input tree.
+ Rebuild(stack, tree, /* consume reference */ true);
+
+ // Return top most node
+ for (CordRepBtree* parent : stack) {
+ if (parent == nullptr) return node;
+ node = parent;
+ }
+
+ // Unreachable
+ assert(false);
+ return nullptr;
+}
+
} // namespace cord_internal
ABSL_NAMESPACE_END
} // namespace absl
diff --git a/absl/strings/internal/cord_rep_btree.h b/absl/strings/internal/cord_rep_btree.h
index bbaa7934..bb38f0c3 100644
--- a/absl/strings/internal/cord_rep_btree.h
+++ b/absl/strings/internal/cord_rep_btree.h
@@ -163,6 +163,12 @@ class CordRepBtree : public CordRep {
// typically after a ref_count.Decrement() on the last reference count.
static void Destroy(CordRepBtree* tree);
+ // Use CordRep::Unref() as we overload for absl::Span<CordRep* const>.
+ using CordRep::Unref;
+
+ // Unrefs all edges in `edges` which are assumed to be 'likely one'.
+ static void Unref(absl::Span<CordRep* const> edges);
+
// Appends / Prepends an existing CordRep instance to this tree.
// The below methods accept three types of input:
// 1) `rep` is a data node (See `IsDataNode` for valid data edges).
@@ -198,6 +204,19 @@ class CordRepBtree : public CordRep {
// Requires `offset + n <= length`. Returns `nullptr` if `n` is zero.
CordRep* SubTree(size_t offset, size_t n);
+ // Removes `n` trailing bytes from `tree`, and returns the resulting tree
+ // or data edge. Returns `tree` if n is zero, and nullptr if n == length.
+ // This function is logically identical to:
+ // result = tree->SubTree(0, tree->length - n);
+ // Unref(tree);
+ // return result;
+ // However, the actual implementation will as much as possible perform 'in
+ // place' modifications on the tree on all nodes and edges that are mutable.
+ // For example, in a fully privately owned tree with the last edge being a
+ // flat of length 12, RemoveSuffix(1) will simply set the length of that data
+ // edge to 11, and reduce the length of all nodes on the edge path by 1.
+ static CordRep* RemoveSuffix(CordRepBtree* tree, size_t n);
+
// Returns the character at the given offset.
char GetCharacter(size_t offset) const;
@@ -221,9 +240,9 @@ class CordRepBtree : public CordRep {
// length of the flat node and involved tree nodes have been increased by
// `span.length()`. The caller is responsible for immediately assigning values
// to all uninitialized data reference by the returned span.
- // Requires `this->refcount.IsOne()`: this function forces the caller to do
- // this fast path check on the top level node, as this is the most commonly
- // shared node of a cord tree.
+ // Requires `this->refcount.IsMutable()`: this function forces the
+ // caller to do this fast path check on the top level node, as this is the
+ // most commonly shared node of a cord tree.
Span<char> GetAppendBuffer(size_t size);
// Returns the `height` of the tree. The height of a tree is limited to
@@ -324,6 +343,11 @@ class CordRepBtree : public CordRep {
// `front.height() + 1`. Requires `back.height() == front.height()`.
static CordRepBtree* New(CordRepBtree* front, CordRepBtree* back);
+ // Creates a fully balanced tree from the provided tree by rebuilding a new
+ // tree from all data edges in the input. This function is automatically
+ // invoked internally when the tree exceeds the maximum height.
+ static CordRepBtree* Rebuild(CordRepBtree* tree);
+
private:
CordRepBtree() = default;
~CordRepBtree() = default;
@@ -368,6 +392,12 @@ class CordRepBtree : public CordRep {
// Requires 0 < `offset` <= length.
Position IndexBefore(size_t offset) const;
+ // Returns the index of the edge ending at (or on) length `length`, and the
+ // number of bytes inside that edge up to `length`. For example, if we have a
+ // Node with 2 edges, one of 10 and one of 20 long, then IndexOfLength(27)
+ // will return {1, 17}, and IndexOfLength(10) will return {0, 10}.
+ Position IndexOfLength(size_t n) const;
+
// Identical to the above function except starting from the position `front`.
// This function is equivalent to `IndexBefore(front.n + offset)`, with
// the difference that this function is optimized to start at `front.index`.
@@ -406,11 +436,28 @@ class CordRepBtree : public CordRep {
// created copy to `new_length`.
CordRepBtree* CopyBeginTo(size_t end, size_t new_length) const;
+ // Returns a tree containing the edges [tree->begin(), end) and length
+ // of `new_length`. This method consumes a reference on the provided
+ // tree, and logically performs the following operation:
+ // result = tree->CopyBeginTo(end, new_length);
+ // CordRep::Unref(tree);
+ // return result;
+ static CordRepBtree* ConsumeBeginTo(CordRepBtree* tree, size_t end,
+ size_t new_length);
+
// Creates a partial copy of this Btree node, copying all edges starting at
// `begin`, adding a reference on each copied edge, and sets the length of
// the newly created copy to `new_length`.
CordRepBtree* CopyToEndFrom(size_t begin, size_t new_length) const;
+ // Extracts and returns the front edge from the provided tree.
+ // This method consumes a reference on the provided tree, and logically
+ // performs the following operation:
+ // edge = CordRep::Ref(tree->Edge(kFront));
+ // CordRep::Unref(tree);
+ // return edge;
+ static CordRep* ExtractFront(CordRepBtree* tree);
+
// Returns a tree containing the result of appending `right` to `left`.
static CordRepBtree* MergeTrees(CordRepBtree* left, CordRepBtree* right);
@@ -420,6 +467,12 @@ class CordRepBtree : public CordRep {
static CordRepBtree* AppendSlow(CordRepBtree*, CordRep* rep);
static CordRepBtree* PrependSlow(CordRepBtree*, CordRep* rep);
+ // Recursively rebuilds `tree` into `stack`. If 'consume` is set to true, the
+ // function will consume a reference on `tree`. `stack` is a null terminated
+ // array containing the new tree's state, with the current leaf node at
+ // stack[0], and parent nodes above that, or null for 'top of tree'.
+ static void Rebuild(CordRepBtree** stack, CordRepBtree* tree, bool consume);
+
// Aligns existing edges to start at index 0, to allow for a new edge to be
// added to the back of the current edges.
inline void AlignBegin();
@@ -459,11 +512,11 @@ class CordRepBtree : public CordRep {
// Returns a partial copy of the current tree containing the first `n` bytes
// of data. `CopyResult` contains both the resulting edge and its height. The
// resulting tree may be less high than the current tree, or even be a single
- // matching data edge. For example, if `n == 1`, then the result will be the
- // single data edge, and height will be set to -1 (one below the owning leaf
- // node). If n == 0, this function returns null.
- // Requires `n <= length`
- CopyResult CopyPrefix(size_t n);
+ // matching data edge if `allow_folding` is set to true.
+ // For example, if `n == 1`, then the result will be the single data edge, and
+ // height will be set to -1 (one below the owning leaf node). If n == 0, this
+ // function returns null. Requires `n <= length`
+ CopyResult CopyPrefix(size_t n, bool allow_folding = true);
// Returns a partial copy of the current tree containing all data starting
// after `offset`. `CopyResult` contains both the resulting edge and its
@@ -619,6 +672,14 @@ inline void CordRepBtree::Destroy(CordRepBtree* tree) {
DestroyTree(tree, tree->begin(), tree->end());
}
+inline void CordRepBtree::Unref(absl::Span<CordRep* const> edges) {
+ for (CordRep* edge : edges) {
+ if (ABSL_PREDICT_FALSE(!edge->refcount.Decrement())) {
+ CordRep::Destroy(edge);
+ }
+ }
+}
+
inline CordRepBtree* CordRepBtree::CopyRaw() const {
auto* tree = static_cast<CordRepBtree*>(::operator new(sizeof(CordRepBtree)));
memcpy(static_cast<void*>(tree), this, sizeof(CordRepBtree));
@@ -762,6 +823,14 @@ inline CordRepBtree::Position CordRepBtree::IndexBefore(Position front,
return {index, offset};
}
+inline CordRepBtree::Position CordRepBtree::IndexOfLength(size_t n) const {
+ assert(n <= length);
+ size_t index = back();
+ size_t strip = length - n;
+ while (strip >= edges_[index]->length) strip -= edges_[index--]->length;
+ return {index, edges_[index]->length - strip};
+}
+
inline CordRepBtree::Position CordRepBtree::IndexBeyond(
const size_t offset) const {
// We need to find the edge which `starting offset` is beyond (>=)`offset`.
@@ -780,7 +849,7 @@ inline CordRepBtree* CordRepBtree::Create(CordRep* rep) {
}
inline Span<char> CordRepBtree::GetAppendBuffer(size_t size) {
- assert(refcount.IsOne());
+ assert(refcount.IsMutable());
CordRepBtree* tree = this;
const int height = this->height();
CordRepBtree* n1 = tree;
@@ -789,21 +858,21 @@ inline Span<char> CordRepBtree::GetAppendBuffer(size_t size) {
switch (height) {
case 3:
tree = tree->Edge(kBack)->btree();
- if (!tree->refcount.IsOne()) return {};
+ if (!tree->refcount.IsMutable()) return {};
n2 = tree;
ABSL_FALLTHROUGH_INTENDED;
case 2:
tree = tree->Edge(kBack)->btree();
- if (!tree->refcount.IsOne()) return {};
+ if (!tree->refcount.IsMutable()) return {};
n1 = tree;
ABSL_FALLTHROUGH_INTENDED;
case 1:
tree = tree->Edge(kBack)->btree();
- if (!tree->refcount.IsOne()) return {};
+ if (!tree->refcount.IsMutable()) return {};
ABSL_FALLTHROUGH_INTENDED;
case 0:
CordRep* edge = tree->Edge(kBack);
- if (!edge->refcount.IsOne()) return {};
+ if (!edge->refcount.IsMutable()) return {};
if (edge->tag < FLAT) return {};
size_t avail = edge->flat()->Capacity() - edge->length;
if (avail == 0) return {};
diff --git a/absl/strings/internal/cord_rep_btree_test.cc b/absl/strings/internal/cord_rep_btree_test.cc
index 073a7d45..be9473d4 100644
--- a/absl/strings/internal/cord_rep_btree_test.cc
+++ b/absl/strings/internal/cord_rep_btree_test.cc
@@ -47,7 +47,9 @@ class CordRepBtreeTestPeer {
namespace {
using ::absl::cordrep_testing::AutoUnref;
+using ::absl::cordrep_testing::CordCollectRepsIf;
using ::absl::cordrep_testing::CordToString;
+using ::absl::cordrep_testing::CordVisitReps;
using ::absl::cordrep_testing::CreateFlatsFromString;
using ::absl::cordrep_testing::CreateRandomString;
using ::absl::cordrep_testing::MakeConcat;
@@ -62,6 +64,7 @@ using ::testing::ElementsAre;
using ::testing::ElementsAreArray;
using ::testing::Eq;
using ::testing::HasSubstr;
+using ::testing::Le;
using ::testing::Ne;
using ::testing::Not;
using ::testing::SizeIs;
@@ -205,14 +208,17 @@ CordRepBtree* MakeTree(size_t size, bool append = true) {
return tree;
}
-CordRepBtree* CreateTree(absl::string_view data, size_t chunk_size) {
- std::vector<CordRep*> flats = CreateFlatsFromString(data, chunk_size);
- auto it = flats.begin();
+CordRepBtree* CreateTree(absl::Span<CordRep* const> reps) {
+ auto it = reps.begin();
CordRepBtree* tree = CordRepBtree::Create(*it);
- while (++it != flats.end()) tree = CordRepBtree::Append(tree, *it);
+ while (++it != reps.end()) tree = CordRepBtree::Append(tree, *it);
return tree;
}
+CordRepBtree* CreateTree(absl::string_view data, size_t chunk_size) {
+ return CreateTree(CreateFlatsFromString(data, chunk_size));
+}
+
CordRepBtree* CreateTreeReverse(absl::string_view data, size_t chunk_size) {
std::vector<CordRep*> flats = CreateFlatsFromString(data, chunk_size);
auto rit = flats.rbegin();
@@ -759,6 +765,63 @@ TEST(CordRepBtreeTest, MergeFuzzTest) {
}
}
+TEST_P(CordRepBtreeTest, RemoveSuffix) {
+ // Create tree of 1, 2 and 3 levels high
+ constexpr size_t max_cap = CordRepBtree::kMaxCapacity;
+ for (size_t cap : {max_cap - 1, max_cap * 2, max_cap * max_cap * 2}) {
+ const std::string data = CreateRandomString(cap * 512);
+
+ {
+ // Verify RemoveSuffix(<all>)
+ AutoUnref refs;
+ CordRepBtree* node = refs.RefIf(shared(), CreateTree(data, 512));
+ EXPECT_THAT(CordRepBtree::RemoveSuffix(node, data.length()), Eq(nullptr));
+
+ // Verify RemoveSuffix(<none>)
+ node = refs.RefIf(shared(), CreateTree(data, 512));
+ EXPECT_THAT(CordRepBtree::RemoveSuffix(node, 0), Eq(node));
+ CordRep::Unref(node);
+ }
+
+ for (int n = 1; n < data.length(); ++n) {
+ AutoUnref refs;
+ auto flats = CreateFlatsFromString(data, 512);
+ CordRepBtree* node = refs.RefIf(shared(), CreateTree(flats));
+ CordRep* rep = refs.Add(CordRepBtree::RemoveSuffix(node, n));
+ EXPECT_THAT(CordToString(rep), Eq(data.substr(0, data.length() - n)));
+
+ // Collect all flats
+ auto is_flat = [](CordRep* rep) { return rep->tag >= FLAT; };
+ std::vector<CordRep*> edges = CordCollectRepsIf(is_flat, rep);
+ ASSERT_THAT(edges.size(), Le(flats.size()));
+
+ // Isolate last edge
+ CordRep* last_edge = edges.back();
+ edges.pop_back();
+ const size_t last_length = rep->length - edges.size() * 512;
+
+ // All flats except the last edge must be kept or copied 'as is'
+ int index = 0;
+ for (CordRep* edge : edges) {
+ ASSERT_THAT(edge, Eq(flats[index++]));
+ ASSERT_THAT(edge->length, Eq(512));
+ }
+
+ // CordRepBtree may optimize small substrings to avoid waste, so only
+ // check for flat sharing / updates where the code should always do this.
+ if (last_length >= 500) {
+ EXPECT_THAT(last_edge, Eq(flats[index++]));
+ if (shared()) {
+ EXPECT_THAT(last_edge->length, Eq(512));
+ } else {
+ EXPECT_TRUE(last_edge->refcount.IsOne());
+ EXPECT_THAT(last_edge->length, Eq(last_length));
+ }
+ }
+ }
+ }
+}
+
TEST(CordRepBtreeTest, SubTree) {
// Create tree of at least 2 levels high
constexpr size_t max_cap = CordRepBtree::kMaxCapacity;
@@ -986,23 +1049,6 @@ TEST_P(CordRepBtreeTest, CreateFromTreeReturnsTree) {
CordRep::Unref(result);
}
-TEST_P(CordRepBtreeTest, ExceedMaxHeight) {
- AutoUnref refs;
- CordRepBtree* tree = MakeLeaf();
- for (int h = 1; h <= CordRepBtree::kMaxHeight; ++h) {
- CordRepBtree* newtree = CordRepBtree::New(tree);
- for (size_t i = 1; i < CordRepBtree::kMaxCapacity; ++i) {
- newtree = CordRepBtree::Append(newtree, CordRep::Ref(tree));
- }
- tree = newtree;
- }
- refs.RefIf(shared(), tree);
-#if defined(GTEST_HAS_DEATH_TEST)
- EXPECT_DEATH(tree = CordRepBtree::Append(tree, MakeFlat("Boom")), ".*");
-#endif
- CordRep::Unref(tree);
-}
-
TEST(CordRepBtreeTest, GetCharacter) {
size_t n = CordRepBtree::kMaxCapacity * CordRepBtree::kMaxCapacity + 2;
std::string data = CreateRandomString(n * 3);
@@ -1389,6 +1435,54 @@ TEST(CordRepBtreeTest, CheckAssertValidShallowVsDeep) {
CordRep::Unref(tree);
}
+TEST_P(CordRepBtreeTest, Rebuild) {
+ for (size_t size : {3, 8, 100, 10000, 1000000}) {
+ SCOPED_TRACE(absl::StrCat("Rebuild @", size));
+
+ std::vector<CordRepFlat*> flats;
+ for (int i = 0; i < size; ++i) {
+ flats.push_back(CordRepFlat::New(2));
+ flats.back()->Data()[0] = 'x';
+ flats.back()->length = 1;
+ }
+
+ // Build the tree into 'right', and each so many 'split_limit' edges,
+ // combine 'left' + 'right' into a new 'left', and start a new 'right'.
+ // This guarantees we get a reasonable amount of chaos in the tree.
+ size_t split_count = 0;
+ size_t split_limit = 3;
+ auto it = flats.begin();
+ CordRepBtree* left = nullptr;
+ CordRepBtree* right = CordRepBtree::New(*it);
+ while (++it != flats.end()) {
+ if (++split_count >= split_limit) {
+ split_limit += split_limit / 16;
+ left = left ? CordRepBtree::Append(left, right) : right;
+ right = CordRepBtree::New(*it);
+ } else {
+ right = CordRepBtree::Append(right, *it);
+ }
+ }
+
+ // Finalize tree
+ left = left ? CordRepBtree::Append(left, right) : right;
+
+ // Rebuild
+ AutoUnref ref;
+ left = ref.Add(CordRepBtree::Rebuild(ref.RefIf(shared(), left)));
+ ASSERT_TRUE(CordRepBtree::IsValid(left));
+
+ // Verify we have the exact same edges in the exact same order.
+ bool ok = true;
+ it = flats.begin();
+ CordVisitReps(left, [&](CordRep* edge) {
+ if (edge->tag < FLAT) return;
+ ok = ok && (it != flats.end() && *it++ == edge);
+ });
+ EXPECT_TRUE(ok && it == flats.end()) << "Rebuild edges mismatch";
+ }
+}
+
} // namespace
} // namespace cord_internal
ABSL_NAMESPACE_END
diff --git a/absl/strings/internal/cord_rep_ring.cc b/absl/strings/internal/cord_rep_ring.cc
index db1f63fa..07c77eb3 100644
--- a/absl/strings/internal/cord_rep_ring.cc
+++ b/absl/strings/internal/cord_rep_ring.cc
@@ -277,7 +277,7 @@ CordRepRing* CordRepRing::Mutable(CordRepRing* rep, size_t extra) {
// Get current number of entries, and check for max capacity.
size_t entries = rep->entries();
- if (!rep->refcount.IsOne()) {
+ if (!rep->refcount.IsMutable()) {
return Copy(rep, rep->head(), rep->tail(), extra);
} else if (entries + extra > rep->capacity()) {
const size_t min_grow = rep->capacity() + rep->capacity() / 2;
@@ -292,10 +292,10 @@ CordRepRing* CordRepRing::Mutable(CordRepRing* rep, size_t extra) {
}
Span<char> CordRepRing::GetAppendBuffer(size_t size) {
- assert(refcount.IsOne());
+ assert(refcount.IsMutable());
index_type back = retreat(tail_);
CordRep* child = entry_child(back);
- if (child->tag >= FLAT && child->refcount.IsOne()) {
+ if (child->tag >= FLAT && child->refcount.IsMutable()) {
size_t capacity = child->flat()->Capacity();
pos_type end_pos = entry_end_pos(back);
size_t data_offset = entry_data_offset(back);
@@ -312,10 +312,10 @@ Span<char> CordRepRing::GetAppendBuffer(size_t size) {
}
Span<char> CordRepRing::GetPrependBuffer(size_t size) {
- assert(refcount.IsOne());
+ assert(refcount.IsMutable());
CordRep* child = entry_child(head_);
size_t data_offset = entry_data_offset(head_);
- if (data_offset && child->refcount.IsOne() && child->tag >= FLAT) {
+ if (data_offset && child->refcount.IsMutable() && child->tag >= FLAT) {
size_t n = (std::min)(data_offset, size);
this->length += n;
begin_pos_ -= n;
@@ -504,7 +504,7 @@ CordRepRing* CordRepRing::Prepend(CordRepRing* rep, CordRep* child) {
CordRepRing* CordRepRing::Append(CordRepRing* rep, absl::string_view data,
size_t extra) {
- if (rep->refcount.IsOne()) {
+ if (rep->refcount.IsMutable()) {
Span<char> avail = rep->GetAppendBuffer(data.length());
if (!avail.empty()) {
memcpy(avail.data(), data.data(), avail.length());
@@ -538,7 +538,7 @@ CordRepRing* CordRepRing::Append(CordRepRing* rep, absl::string_view data,
CordRepRing* CordRepRing::Prepend(CordRepRing* rep, absl::string_view data,
size_t extra) {
- if (rep->refcount.IsOne()) {
+ if (rep->refcount.IsMutable()) {
Span<char> avail = rep->GetPrependBuffer(data.length());
if (!avail.empty()) {
const char* tail = data.data() + data.length() - avail.length();
@@ -678,7 +678,7 @@ CordRepRing* CordRepRing::SubRing(CordRepRing* rep, size_t offset,
Position tail = rep->FindTail(head.index, offset + len);
const size_t new_entries = rep->entries(head.index, tail.index);
- if (rep->refcount.IsOne() && extra <= (rep->capacity() - new_entries)) {
+ if (rep->refcount.IsMutable() && extra <= (rep->capacity() - new_entries)) {
// We adopt a privately owned rep and no extra entries needed.
if (head.index != rep->head_) UnrefEntries(rep, rep->head_, head.index);
if (tail.index != rep->tail_) UnrefEntries(rep, tail.index, rep->tail_);
@@ -715,7 +715,7 @@ CordRepRing* CordRepRing::RemovePrefix(CordRepRing* rep, size_t len,
}
Position head = rep->Find(len);
- if (rep->refcount.IsOne()) {
+ if (rep->refcount.IsMutable()) {
if (head.index != rep->head_) UnrefEntries(rep, rep->head_, head.index);
rep->head_ = head.index;
} else {
@@ -745,7 +745,7 @@ CordRepRing* CordRepRing::RemoveSuffix(CordRepRing* rep, size_t len,
}
Position tail = rep->FindTail(rep->length - len);
- if (rep->refcount.IsOne()) {
+ if (rep->refcount.IsMutable()) {
// We adopt a privately owned rep, scrub.
if (tail.index != rep->tail_) UnrefEntries(rep, tail.index, rep->tail_);
rep->tail_ = tail.index;
diff --git a/absl/strings/internal/cord_rep_ring.h b/absl/strings/internal/cord_rep_ring.h
index 44db8494..2000e21e 100644
--- a/absl/strings/internal/cord_rep_ring.h
+++ b/absl/strings/internal/cord_rep_ring.h
@@ -383,8 +383,8 @@ class CordRepRing : public CordRep {
// Destroys the provided ring buffer, decrementing the reference count of all
// contained child CordReps. The provided 1\`rep` should have a ref count of
- // one (pre decrement destroy call observing `refcount.IsOne()`) or zero (post
- // decrement destroy call observing `!refcount.Decrement()`).
+ // one (pre decrement destroy call observing `refcount.IsOne()`) or zero
+ // (post decrement destroy call observing `!refcount.Decrement()`).
static void Destroy(CordRepRing* rep);
// Returns a mutable reference to the logical end position array.
diff --git a/absl/strings/internal/cord_rep_test_util.h b/absl/strings/internal/cord_rep_test_util.h
index bc500064..ad828af2 100644
--- a/absl/strings/internal/cord_rep_test_util.h
+++ b/absl/strings/internal/cord_rep_test_util.h
@@ -115,6 +115,41 @@ inline cord_internal::CordRepBtree* CordRepBtreeFromFlats(
return node;
}
+template <typename Fn>
+inline void CordVisitReps(cord_internal::CordRep* rep, Fn&& fn) {
+ fn(rep);
+ while (rep->tag == cord_internal::SUBSTRING) {
+ rep = rep->substring()->child;
+ fn(rep);
+ }
+ if (rep->tag == cord_internal::BTREE) {
+ for (cord_internal::CordRep* edge : rep->btree()->Edges()) {
+ CordVisitReps(edge, fn);
+ }
+ } else if (rep->tag == cord_internal::CONCAT) {
+ CordVisitReps(rep->concat()->left, fn);
+ CordVisitReps(rep->concat()->right, fn);
+ }
+}
+
+template <typename Predicate>
+inline std::vector<cord_internal::CordRep*> CordCollectRepsIf(
+ Predicate&& predicate, cord_internal::CordRep* rep) {
+ std::vector<cord_internal::CordRep*> reps;
+ CordVisitReps(rep, [&reps, &predicate](cord_internal::CordRep* rep) {
+ if (predicate(rep)) reps.push_back(rep);
+ });
+ return reps;
+}
+
+inline std::vector<cord_internal::CordRep*> CordCollectReps(
+ cord_internal::CordRep* rep) {
+ std::vector<cord_internal::CordRep*> reps;
+ auto fn = [&reps](cord_internal::CordRep* rep) { reps.push_back(rep); };
+ CordVisitReps(rep, fn);
+ return reps;
+}
+
inline void CordToString(cord_internal::CordRep* rep, std::string& s) {
size_t offset = 0;
size_t length = rep->length;
diff --git a/absl/strings/internal/cordz_update_tracker.h b/absl/strings/internal/cordz_update_tracker.h
index 02efcc3a..1f764486 100644
--- a/absl/strings/internal/cordz_update_tracker.h
+++ b/absl/strings/internal/cordz_update_tracker.h
@@ -39,6 +39,7 @@ class CordzUpdateTracker {
// Tracked update methods.
enum MethodIdentifier {
kUnknown,
+ kAppendBuffer,
kAppendCord,
kAppendExternalMemory,
kAppendString,
@@ -54,6 +55,7 @@ class CordzUpdateTracker {
kMoveAppendCord,
kMoveAssignCord,
kMovePrependCord,
+ kPrependBuffer,
kPrependCord,
kPrependString,
kRemovePrefix,
diff --git a/absl/strings/internal/cordz_update_tracker_test.cc b/absl/strings/internal/cordz_update_tracker_test.cc
index fcd17df7..2348a175 100644
--- a/absl/strings/internal/cordz_update_tracker_test.cc
+++ b/absl/strings/internal/cordz_update_tracker_test.cc
@@ -37,6 +37,7 @@ using Methods = std::array<Method, Method::kNumMethods>;
// Returns an array of all methods defined in `MethodIdentifier`
Methods AllMethods() {
return Methods{Method::kUnknown,
+ Method::kAppendBuffer,
Method::kAppendCord,
Method::kAppendExternalMemory,
Method::kAppendString,
@@ -52,6 +53,7 @@ Methods AllMethods() {
Method::kMoveAppendCord,
Method::kMoveAssignCord,
Method::kMovePrependCord,
+ Method::kPrependBuffer,
Method::kPrependCord,
Method::kPrependString,
Method::kRemovePrefix,
diff --git a/absl/strings/numbers.h b/absl/strings/numbers.h
index 1780bb44..4ae07c2d 100644
--- a/absl/strings/numbers.h
+++ b/absl/strings/numbers.h
@@ -96,6 +96,25 @@ ABSL_MUST_USE_RESULT bool SimpleAtod(absl::string_view str, double* out);
// unspecified state.
ABSL_MUST_USE_RESULT bool SimpleAtob(absl::string_view str, bool* out);
+// SimpleHexAtoi()
+//
+// Converts a hexadecimal string (optionally followed or preceded by ASCII
+// whitespace) to an integer, returning `true` if successful. Only valid base-16
+// hexadecimal integers whose value falls within the range of the integer type
+// (optionally preceded by a `+` or `-`) can be converted. A valid hexadecimal
+// value may include both upper and lowercase character symbols, and may
+// optionally include a leading "0x" (or "0X") number prefix, which is ignored
+// by this function. If any errors are encountered, this function returns
+// `false`, leaving `out` in an unspecified state.
+template <typename int_type>
+ABSL_MUST_USE_RESULT bool SimpleHexAtoi(absl::string_view str, int_type* out);
+
+// Overloads of SimpleHexAtoi() for 128 bit integers.
+ABSL_MUST_USE_RESULT inline bool SimpleHexAtoi(absl::string_view str,
+ absl::int128* out);
+ABSL_MUST_USE_RESULT inline bool SimpleHexAtoi(absl::string_view str,
+ absl::uint128* out);
+
ABSL_NAMESPACE_END
} // namespace absl
@@ -260,6 +279,21 @@ ABSL_MUST_USE_RESULT inline bool SimpleAtoi(absl::string_view str,
return numbers_internal::safe_strtou128_base(str, out, 10);
}
+template <typename int_type>
+ABSL_MUST_USE_RESULT bool SimpleHexAtoi(absl::string_view str, int_type* out) {
+ return numbers_internal::safe_strtoi_base(str, out, 16);
+}
+
+ABSL_MUST_USE_RESULT inline bool SimpleHexAtoi(absl::string_view str,
+ absl::int128* out) {
+ return numbers_internal::safe_strto128_base(str, out, 16);
+}
+
+ABSL_MUST_USE_RESULT inline bool SimpleHexAtoi(absl::string_view str,
+ absl::uint128* out) {
+ return numbers_internal::safe_strtou128_base(str, out, 16);
+}
+
ABSL_NAMESPACE_END
} // namespace absl
diff --git a/absl/strings/numbers_test.cc b/absl/strings/numbers_test.cc
index f3103106..498c210d 100644
--- a/absl/strings/numbers_test.cc
+++ b/absl/strings/numbers_test.cc
@@ -47,6 +47,7 @@
namespace {
using absl::SimpleAtoi;
+using absl::SimpleHexAtoi;
using absl::numbers_internal::kSixDigitsToBufferSize;
using absl::numbers_internal::safe_strto32_base;
using absl::numbers_internal::safe_strto64_base;
@@ -468,6 +469,148 @@ TEST(NumbersTest, Atoenum) {
VerifySimpleAtoiGood<E_biguint>(E_biguint_max32, E_biguint_max32);
}
+template <typename int_type, typename in_val_type>
+void VerifySimpleHexAtoiGood(in_val_type in_value, int_type exp_value) {
+ std::string s;
+ // uint128 can be streamed but not StrCat'd
+ absl::strings_internal::OStringStream strm(&s);
+ if (in_value >= 0) {
+ strm << std::hex << in_value;
+ } else {
+ // Inefficient for small integers, but works with all integral types.
+ strm << "-" << std::hex << -absl::uint128(in_value);
+ }
+ int_type x = static_cast<int_type>(~exp_value);
+ EXPECT_TRUE(SimpleHexAtoi(s, &x))
+ << "in_value=" << std::hex << in_value << " s=" << s << " x=" << x;
+ EXPECT_EQ(exp_value, x);
+ x = static_cast<int_type>(~exp_value);
+ EXPECT_TRUE(SimpleHexAtoi(
+ s.c_str(), &x)); // NOLINT: readability-redundant-string-conversions
+ EXPECT_EQ(exp_value, x);
+}
+
+template <typename int_type, typename in_val_type>
+void VerifySimpleHexAtoiBad(in_val_type in_value) {
+ std::string s;
+ // uint128 can be streamed but not StrCat'd
+ absl::strings_internal::OStringStream strm(&s);
+ if (in_value >= 0) {
+ strm << std::hex << in_value;
+ } else {
+ // Inefficient for small integers, but works with all integral types.
+ strm << "-" << std::hex << -absl::uint128(in_value);
+ }
+ int_type x;
+ EXPECT_FALSE(SimpleHexAtoi(s, &x));
+ EXPECT_FALSE(SimpleHexAtoi(
+ s.c_str(), &x)); // NOLINT: readability-redundant-string-conversions
+}
+
+TEST(NumbersTest, HexAtoi) {
+ // SimpleHexAtoi(absl::string_view, int32_t)
+ VerifySimpleHexAtoiGood<int32_t>(0, 0);
+ VerifySimpleHexAtoiGood<int32_t>(0x42, 0x42);
+ VerifySimpleHexAtoiGood<int32_t>(-0x42, -0x42);
+
+ VerifySimpleHexAtoiGood<int32_t>(std::numeric_limits<int32_t>::min(),
+ std::numeric_limits<int32_t>::min());
+ VerifySimpleHexAtoiGood<int32_t>(std::numeric_limits<int32_t>::max(),
+ std::numeric_limits<int32_t>::max());
+
+ // SimpleHexAtoi(absl::string_view, uint32_t)
+ VerifySimpleHexAtoiGood<uint32_t>(0, 0);
+ VerifySimpleHexAtoiGood<uint32_t>(0x42, 0x42);
+ VerifySimpleHexAtoiBad<uint32_t>(-0x42);
+
+ VerifySimpleHexAtoiBad<uint32_t>(std::numeric_limits<int32_t>::min());
+ VerifySimpleHexAtoiGood<uint32_t>(std::numeric_limits<int32_t>::max(),
+ std::numeric_limits<int32_t>::max());
+ VerifySimpleHexAtoiGood<uint32_t>(std::numeric_limits<uint32_t>::max(),
+ std::numeric_limits<uint32_t>::max());
+ VerifySimpleHexAtoiBad<uint32_t>(std::numeric_limits<int64_t>::min());
+ VerifySimpleHexAtoiBad<uint32_t>(std::numeric_limits<int64_t>::max());
+ VerifySimpleHexAtoiBad<uint32_t>(std::numeric_limits<uint64_t>::max());
+
+ // SimpleHexAtoi(absl::string_view, int64_t)
+ VerifySimpleHexAtoiGood<int64_t>(0, 0);
+ VerifySimpleHexAtoiGood<int64_t>(0x42, 0x42);
+ VerifySimpleHexAtoiGood<int64_t>(-0x42, -0x42);
+
+ VerifySimpleHexAtoiGood<int64_t>(std::numeric_limits<int32_t>::min(),
+ std::numeric_limits<int32_t>::min());
+ VerifySimpleHexAtoiGood<int64_t>(std::numeric_limits<int32_t>::max(),
+ std::numeric_limits<int32_t>::max());
+ VerifySimpleHexAtoiGood<int64_t>(std::numeric_limits<uint32_t>::max(),
+ std::numeric_limits<uint32_t>::max());
+ VerifySimpleHexAtoiGood<int64_t>(std::numeric_limits<int64_t>::min(),
+ std::numeric_limits<int64_t>::min());
+ VerifySimpleHexAtoiGood<int64_t>(std::numeric_limits<int64_t>::max(),
+ std::numeric_limits<int64_t>::max());
+ VerifySimpleHexAtoiBad<int64_t>(std::numeric_limits<uint64_t>::max());
+
+ // SimpleHexAtoi(absl::string_view, uint64_t)
+ VerifySimpleHexAtoiGood<uint64_t>(0, 0);
+ VerifySimpleHexAtoiGood<uint64_t>(0x42, 0x42);
+ VerifySimpleHexAtoiBad<uint64_t>(-0x42);
+
+ VerifySimpleHexAtoiBad<uint64_t>(std::numeric_limits<int32_t>::min());
+ VerifySimpleHexAtoiGood<uint64_t>(std::numeric_limits<int32_t>::max(),
+ std::numeric_limits<int32_t>::max());
+ VerifySimpleHexAtoiGood<uint64_t>(std::numeric_limits<uint32_t>::max(),
+ std::numeric_limits<uint32_t>::max());
+ VerifySimpleHexAtoiBad<uint64_t>(std::numeric_limits<int64_t>::min());
+ VerifySimpleHexAtoiGood<uint64_t>(std::numeric_limits<int64_t>::max(),
+ std::numeric_limits<int64_t>::max());
+ VerifySimpleHexAtoiGood<uint64_t>(std::numeric_limits<uint64_t>::max(),
+ std::numeric_limits<uint64_t>::max());
+
+ // SimpleHexAtoi(absl::string_view, absl::uint128)
+ VerifySimpleHexAtoiGood<absl::uint128>(0, 0);
+ VerifySimpleHexAtoiGood<absl::uint128>(0x42, 0x42);
+ VerifySimpleHexAtoiBad<absl::uint128>(-0x42);
+
+ VerifySimpleHexAtoiBad<absl::uint128>(std::numeric_limits<int32_t>::min());
+ VerifySimpleHexAtoiGood<absl::uint128>(std::numeric_limits<int32_t>::max(),
+ std::numeric_limits<int32_t>::max());
+ VerifySimpleHexAtoiGood<absl::uint128>(std::numeric_limits<uint32_t>::max(),
+ std::numeric_limits<uint32_t>::max());
+ VerifySimpleHexAtoiBad<absl::uint128>(std::numeric_limits<int64_t>::min());
+ VerifySimpleHexAtoiGood<absl::uint128>(std::numeric_limits<int64_t>::max(),
+ std::numeric_limits<int64_t>::max());
+ VerifySimpleHexAtoiGood<absl::uint128>(std::numeric_limits<uint64_t>::max(),
+ std::numeric_limits<uint64_t>::max());
+ VerifySimpleHexAtoiGood<absl::uint128>(
+ std::numeric_limits<absl::uint128>::max(),
+ std::numeric_limits<absl::uint128>::max());
+
+ // Some other types
+ VerifySimpleHexAtoiGood<int>(-0x42, -0x42);
+ VerifySimpleHexAtoiGood<int32_t>(-0x42, -0x42);
+ VerifySimpleHexAtoiGood<uint32_t>(0x42, 0x42);
+ VerifySimpleHexAtoiGood<unsigned int>(0x42, 0x42);
+ VerifySimpleHexAtoiGood<int64_t>(-0x42, -0x42);
+ VerifySimpleHexAtoiGood<long>(-0x42, -0x42); // NOLINT: runtime-int
+ VerifySimpleHexAtoiGood<uint64_t>(0x42, 0x42);
+ VerifySimpleHexAtoiGood<size_t>(0x42, 0x42);
+ VerifySimpleHexAtoiGood<std::string::size_type>(0x42, 0x42);
+
+ // Number prefix
+ int32_t value;
+ EXPECT_TRUE(safe_strto32_base("0x34234324", &value, 16));
+ EXPECT_EQ(0x34234324, value);
+
+ EXPECT_TRUE(safe_strto32_base("0X34234324", &value, 16));
+ EXPECT_EQ(0x34234324, value);
+
+ // ASCII whitespace
+ EXPECT_TRUE(safe_strto32_base(" \t\n 34234324", &value, 16));
+ EXPECT_EQ(0x34234324, value);
+
+ EXPECT_TRUE(safe_strto32_base("34234324 \t\n ", &value, 16));
+ EXPECT_EQ(0x34234324, value);
+}
+
TEST(stringtest, safe_strto32_base) {
int32_t value;
EXPECT_TRUE(safe_strto32_base("0x34234324", &value, 16));
diff --git a/absl/strings/str_split_test.cc b/absl/strings/str_split_test.cc
index f472f9ed..1b4427b8 100644
--- a/absl/strings/str_split_test.cc
+++ b/absl/strings/str_split_test.cc
@@ -943,8 +943,14 @@ TEST(Delimiter, ByLength) {
}
TEST(Split, WorksWithLargeStrings) {
+#if defined(ABSL_HAVE_ADDRESS_SANITIZER) || \
+ defined(ABSL_HAVE_MEMORY_SANITIZER) || defined(ABSL_HAVE_THREAD_SANITIZER)
+ constexpr size_t kSize = (uint32_t{1} << 26) + 1; // 64M + 1 byte
+#else
+ constexpr size_t kSize = (uint32_t{1} << 31) + 1; // 2G + 1 byte
+#endif
if (sizeof(size_t) > 4) {
- std::string s((uint32_t{1} << 31) + 1, 'x'); // 2G + 1 byte
+ std::string s(kSize, 'x');
s.back() = '-';
std::vector<absl::string_view> v = absl::StrSplit(s, '-');
EXPECT_EQ(2, v.size());
diff --git a/absl/strings/substitute.cc b/absl/strings/substitute.cc
index 1f3c7409..8980b198 100644
--- a/absl/strings/substitute.cc
+++ b/absl/strings/substitute.cc
@@ -75,7 +75,8 @@ void SubstituteAndAppendArray(std::string* output, absl::string_view format,
// Build the string.
size_t original_size = output->size();
- strings_internal::STLStringResizeUninitialized(output, original_size + size);
+ strings_internal::STLStringResizeUninitializedAmortized(output,
+ original_size + size);
char* target = &(*output)[original_size];
for (size_t i = 0; i < format.size(); i++) {
if (format[i] == '$') {
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-05 05:57:53 +0000