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-rw-r--r--absl/base/internal/exception_safety_testing.h185
1 files changed, 119 insertions, 66 deletions
diff --git a/absl/base/internal/exception_safety_testing.h b/absl/base/internal/exception_safety_testing.h
index d2742456..a0a70d91 100644
--- a/absl/base/internal/exception_safety_testing.h
+++ b/absl/base/internal/exception_safety_testing.h
@@ -6,6 +6,7 @@
#include <cstddef>
#include <cstdint>
#include <functional>
+#include <initializer_list>
#include <iosfwd>
#include <string>
#include <unordered_map>
@@ -13,6 +14,7 @@
#include "gtest/gtest.h"
#include "absl/base/config.h"
#include "absl/base/internal/pretty_function.h"
+#include "absl/memory/memory.h"
#include "absl/meta/type_traits.h"
#include "absl/strings/string_view.h"
#include "absl/strings/substitute.h"
@@ -43,6 +45,8 @@ constexpr NoThrow operator&(NoThrow a, NoThrow b) {
}
namespace exceptions_internal {
+struct NoThrowTag {};
+
constexpr bool ThrowingAllowed(NoThrow flags, NoThrow flag) {
return !static_cast<bool>(flags & flag);
}
@@ -92,8 +96,46 @@ class TrackedObject {
friend struct ::absl::AllocInspector;
};
+
+template <typename T, typename... Checkers>
+testing::AssertionResult TestInvariants(const T& t, const TestException& e,
+ int count,
+ const Checkers&... checkers) {
+ auto out = AbslCheckInvariants(t);
+ // Don't bother with the checkers if the class invariants are already broken.
+ bool dummy[] = {true,
+ (out && (out = testing::AssertionResult(checkers(t))))...};
+ static_cast<void>(dummy);
+
+ return out ? out
+ : out << " Caused by exception " << count << "thrown by "
+ << e.what();
+}
+
+template <typename T, typename EqualTo>
+class StrongGuaranteeTester {
+ public:
+ explicit StrongGuaranteeTester(std::unique_ptr<T> t_ptr, EqualTo eq) noexcept
+ : val_(std::move(t_ptr)), eq_(eq) {}
+
+ testing::AssertionResult operator()(const T& other) const {
+ return eq_(*val_, other) ? testing::AssertionSuccess()
+ : testing::AssertionFailure() << "State changed";
+ }
+
+ private:
+ std::unique_ptr<T> val_;
+ EqualTo eq_;
+};
} // namespace exceptions_internal
+extern exceptions_internal::NoThrowTag no_throw_ctor;
+
+// These are useful for tests which just construct objects and make sure there
+// are no leaks.
+inline void SetCountdown() { exceptions_internal::countdown = 0; }
+inline void UnsetCountdown() { exceptions_internal::countdown = -1; }
+
// A test class which is contextually convertible to bool. The conversion can
// be instrumented to throw at a controlled time.
class ThrowingBool {
@@ -152,6 +194,9 @@ class ThrowingValue : private exceptions_internal::TrackedObject {
dummy_ = i;
}
+ ThrowingValue(int i, exceptions_internal::NoThrowTag) noexcept
+ : TrackedObject(ABSL_PRETTY_FUNCTION), dummy_(i) {}
+
// absl expects nothrow destructors
~ThrowingValue() noexcept = default;
@@ -173,22 +218,22 @@ class ThrowingValue : private exceptions_internal::TrackedObject {
// Arithmetic Operators
ThrowingValue operator+(const ThrowingValue& other) const {
exceptions_internal::MaybeThrow(ABSL_PRETTY_FUNCTION);
- return ThrowingValue(dummy_ + other.dummy_, NoThrowTag{});
+ return ThrowingValue(dummy_ + other.dummy_, no_throw_ctor);
}
ThrowingValue operator+() const {
exceptions_internal::MaybeThrow(ABSL_PRETTY_FUNCTION);
- return ThrowingValue(dummy_, NoThrowTag{});
+ return ThrowingValue(dummy_, no_throw_ctor);
}
ThrowingValue operator-(const ThrowingValue& other) const {
exceptions_internal::MaybeThrow(ABSL_PRETTY_FUNCTION);
- return ThrowingValue(dummy_ - other.dummy_, NoThrowTag{});
+ return ThrowingValue(dummy_ - other.dummy_, no_throw_ctor);
}
ThrowingValue operator-() const {
exceptions_internal::MaybeThrow(ABSL_PRETTY_FUNCTION);
- return ThrowingValue(-dummy_, NoThrowTag{});
+ return ThrowingValue(-dummy_, no_throw_ctor);
}
ThrowingValue& operator++() {
@@ -199,7 +244,7 @@ class ThrowingValue : private exceptions_internal::TrackedObject {
ThrowingValue operator++(int) {
exceptions_internal::MaybeThrow(ABSL_PRETTY_FUNCTION);
- auto out = ThrowingValue(dummy_, NoThrowTag{});
+ auto out = ThrowingValue(dummy_, no_throw_ctor);
++dummy_;
return out;
}
@@ -212,34 +257,34 @@ class ThrowingValue : private exceptions_internal::TrackedObject {
ThrowingValue operator--(int) {
exceptions_internal::MaybeThrow(ABSL_PRETTY_FUNCTION);
- auto out = ThrowingValue(dummy_, NoThrowTag{});
+ auto out = ThrowingValue(dummy_, no_throw_ctor);
--dummy_;
return out;
}
ThrowingValue operator*(const ThrowingValue& other) const {
exceptions_internal::MaybeThrow(ABSL_PRETTY_FUNCTION);
- return ThrowingValue(dummy_ * other.dummy_, NoThrowTag{});
+ return ThrowingValue(dummy_ * other.dummy_, no_throw_ctor);
}
ThrowingValue operator/(const ThrowingValue& other) const {
exceptions_internal::MaybeThrow(ABSL_PRETTY_FUNCTION);
- return ThrowingValue(dummy_ / other.dummy_, NoThrowTag{});
+ return ThrowingValue(dummy_ / other.dummy_, no_throw_ctor);
}
ThrowingValue operator%(const ThrowingValue& other) const {
exceptions_internal::MaybeThrow(ABSL_PRETTY_FUNCTION);
- return ThrowingValue(dummy_ % other.dummy_, NoThrowTag{});
+ return ThrowingValue(dummy_ % other.dummy_, no_throw_ctor);
}
ThrowingValue operator<<(int shift) const {
exceptions_internal::MaybeThrow(ABSL_PRETTY_FUNCTION);
- return ThrowingValue(dummy_ << shift, NoThrowTag{});
+ return ThrowingValue(dummy_ << shift, no_throw_ctor);
}
ThrowingValue operator>>(int shift) const {
exceptions_internal::MaybeThrow(ABSL_PRETTY_FUNCTION);
- return ThrowingValue(dummy_ >> shift, NoThrowTag{});
+ return ThrowingValue(dummy_ >> shift, no_throw_ctor);
}
// Comparison Operators
@@ -293,22 +338,22 @@ class ThrowingValue : private exceptions_internal::TrackedObject {
// Bitwise Logical Operators
ThrowingValue operator~() const {
exceptions_internal::MaybeThrow(ABSL_PRETTY_FUNCTION);
- return ThrowingValue(~dummy_, NoThrowTag{});
+ return ThrowingValue(~dummy_, no_throw_ctor);
}
ThrowingValue operator&(const ThrowingValue& other) const {
exceptions_internal::MaybeThrow(ABSL_PRETTY_FUNCTION);
- return ThrowingValue(dummy_ & other.dummy_, NoThrowTag{});
+ return ThrowingValue(dummy_ & other.dummy_, no_throw_ctor);
}
ThrowingValue operator|(const ThrowingValue& other) const {
exceptions_internal::MaybeThrow(ABSL_PRETTY_FUNCTION);
- return ThrowingValue(dummy_ | other.dummy_, NoThrowTag{});
+ return ThrowingValue(dummy_ | other.dummy_, no_throw_ctor);
}
ThrowingValue operator^(const ThrowingValue& other) const {
exceptions_internal::MaybeThrow(ABSL_PRETTY_FUNCTION);
- return ThrowingValue(dummy_ ^ other.dummy_, NoThrowTag{});
+ return ThrowingValue(dummy_ ^ other.dummy_, no_throw_ctor);
}
// Compound Assignment operators
@@ -434,10 +479,6 @@ class ThrowingValue : private exceptions_internal::TrackedObject {
const int& Get() const noexcept { return dummy_; }
private:
- struct NoThrowTag {};
- ThrowingValue(int i, NoThrowTag) noexcept
- : TrackedObject(ABSL_PRETTY_FUNCTION), dummy_(i) {}
-
int dummy_;
};
// While not having to do with exceptions, explicitly delete comma operator, to
@@ -596,7 +637,9 @@ int ThrowingAllocator<T, Throws>::next_id_ = 0;
// Inspects the constructions and destructions of anything inheriting from
// TrackedObject. Place this as a member variable in a test fixture to ensure
-// that every ThrowingValue was constructed and destroyed correctly.
+// that every ThrowingValue was constructed and destroyed correctly. This also
+// allows us to safely "leak" TrackedObjects, as AllocInspector will destroy
+// everything left over in its destructor.
struct AllocInspector {
AllocInspector() = default;
~AllocInspector() {
@@ -609,69 +652,79 @@ struct AllocInspector {
}
};
-// Tests that performing operation Op on a T follows the basic exception safety
-// guarantee.
-//
-// Parameters:
-// * T: the type under test.
-// * FunctionFromTPtrToVoid: A functor exercising the function under test. It
-// should take a T* and return void.
-//
-// There must also be a function named `AbslCheckInvariants` in an associated
-// namespace of T which takes a const T& and returns true if the T's class
-// invariants hold, and false if they don't.
-template <typename T, typename FunctionFromTPtrToVoid>
-testing::AssertionResult TestBasicGuarantee(T* t, FunctionFromTPtrToVoid&& op) {
+// Tests for resource leaks by attempting to construct a T using args repeatedly
+// until successful, using the countdown method. Side effects can then be
+// tested for resource leaks. If an AllocInspector is present in the test
+// fixture, then this will also test that memory resources are not leaked as
+// long as T allocates TrackedObjects.
+template <typename T, typename... Args>
+T TestThrowingCtor(Args&&... args) {
+ struct Cleanup {
+ ~Cleanup() { UnsetCountdown(); }
+ };
+ Cleanup c;
for (int countdown = 0;; ++countdown) {
exceptions_internal::countdown = countdown;
try {
- op(t);
- break;
- } catch (const exceptions_internal::TestException& e) {
- if (!AbslCheckInvariants(*t)) {
- return exceptions_internal::FailureMessage(e, countdown)
- << " broke invariants.";
- }
+ return T(std::forward<Args>(args)...);
+ } catch (const exceptions_internal::TestException&) {
}
}
- exceptions_internal::countdown = -1;
- return testing::AssertionSuccess();
}
-// Tests that performing operation Op on a T follows the strong exception safety
-// guarantee.
+// Tests that performing operation Op on a T follows exception safety
+// guarantees. By default only tests the basic guarantee.
//
// Parameters:
-// * T: the type under test. T must be copy-constructable and
-// equality-comparible.
+// * T: the type under test.
// * FunctionFromTPtrToVoid: A functor exercising the function under test. It
-// should take a T* and return void.
-//
-// There must also be a function named `AbslCheckInvariants` in an associated
-// namespace of T which takes a const T& and returns true if the T's class
-// invariants hold, and false if they don't.
-template <typename T, typename FunctionFromTPtrToVoid>
-testing::AssertionResult TestStrongGuarantee(T* t,
- FunctionFromTPtrToVoid&& op) {
- exceptions_internal::countdown = -1;
- for (auto countdown = 0;; ++countdown) {
- T dup = *t;
+// should take a T* and return void.
+// * Checkers: Any number of functions taking a const T& and returning
+// anything contextually convertible to bool. If a testing::AssertionResult
+// is used then the error message is kept. These test invariants related to
+// the operation. To test the strong guarantee, pass
+// absl::StrongGuarantee(...) as one of these arguments if T has operator==.
+// Some types for which the strong guarantee makes sense don't have operator==
+// (eg std::any). A function capturing *t or a T equal to it, taking a const
+// T&, and returning contextually-convertible-to-bool may be passed instead.
+template <typename T, typename FunctionFromTPtrToVoid, typename... Checkers>
+testing::AssertionResult TestExceptionSafety(T* t, FunctionFromTPtrToVoid&& op,
+ const Checkers&... checkers) {
+ auto out = testing::AssertionSuccess();
+ for (int countdown = 0;; ++countdown) {
exceptions_internal::countdown = countdown;
try {
op(t);
break;
} catch (const exceptions_internal::TestException& e) {
- if (!AbslCheckInvariants(*t)) {
- return exceptions_internal::FailureMessage(e, countdown)
- << " broke invariants.";
- }
- if (dup != *t)
- return exceptions_internal::FailureMessage(e, countdown)
- << " changed state.";
+ out = exceptions_internal::TestInvariants(*t, e, countdown, checkers...);
+ if (!out) return out;
}
}
- exceptions_internal::countdown = -1;
- return testing::AssertionSuccess();
+ UnsetCountdown();
+ return out;
+}
+
+// Returns a functor to test for the strong exception-safety guarantee. If T is
+// copyable, use the const T& overload, otherwise pass a unique_ptr<T>.
+// Equality comparisons are made against the T provided and default to using
+// operator==. See the documentation for TestExceptionSafety if T doesn't have
+// operator== but the strong guarantee still makes sense for it.
+//
+// Parameters:
+// * T: The type under test.
+template <typename T, typename EqualTo = std::equal_to<T>>
+exceptions_internal::StrongGuaranteeTester<T, EqualTo> StrongGuarantee(
+ const T& t, EqualTo eq = EqualTo()) {
+ return exceptions_internal::StrongGuaranteeTester<T, EqualTo>(
+ absl::make_unique<T>(t), eq);
+}
+
+template <typename T, typename EqualTo = std::equal_to<T>>
+exceptions_internal::StrongGuaranteeTester<T, EqualTo> PointeeStrongGuarantee(
+ std::unique_ptr<T> t_ptr, EqualTo eq = EqualTo()) {
+ return exceptions_internal::StrongGuaranteeTester<T, EqualTo>(
+ std::move(t_ptr), eq);
}
} // namespace absl
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