Abseil Common Libraries (C++) (grcp 依赖) https://abseil.io/
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Export of internal Abseil changes -- f012012ef78234a6a4585321b67d7b7c92ebc266 by Laramie Leavitt <lar@google.com>: Slight restructuring of absl/random/internal randen implementation. Convert round-keys.inc into randen_round_keys.cc file. Consistently use a 128-bit pointer type for internal method parameters. This allows simpler pointer arithmetic in C++ & permits removal of some constants and casts. Remove some redundancy in comments & constexpr variables. Specifically, all references to Randen algorithm parameters use RandenTraits; duplication in RandenSlow removed. PiperOrigin-RevId: 312190313 -- dc8b42e054046741e9ed65335bfdface997c6063 by Abseil Team <absl-team@google.com>: Internal change. PiperOrigin-RevId: 312167304 -- f13d248fafaf206492c1362c3574031aea3abaf7 by Matthew Brown <matthewbr@google.com>: Cleanup StrFormat extensions a little. PiperOrigin-RevId: 312166336 -- 9d9117589667afe2332bb7ad42bc967ca7c54502 by Derek Mauro <dmauro@google.com>: Internal change PiperOrigin-RevId: 312105213 -- 9a12b9b3aa0e59b8ee6cf9408ed0029045543a9b by Abseil Team <absl-team@google.com>: Complete IGNORE_TYPE macro renaming. PiperOrigin-RevId: 311999699 -- 64756f20d61021d999bd0d4c15e9ad3857382f57 by Gennadiy Rozental <rogeeff@google.com>: Switch to fixed bytes specific default value. This fixes the Abseil Flags for big endian platforms. PiperOrigin-RevId: 311844448 -- bdbe6b5b29791dbc3816ada1828458b3010ff1e9 by Laramie Leavitt <lar@google.com>: Change many distribution tests to use pcg_engine as a deterministic source of entropy. It's reasonable to test that the BitGen itself has good entropy, however when testing the cross product of all random distributions x all the architecture variations x all submitted changes results in a large number of tests. In order to account for these failures while still using good entropy requires that our allowed sigma need to account for all of these independent tests. Our current sigma values are too restrictive, and we see a lot of failures, so we have to either relax the sigma values or convert some of the statistical tests to use deterministic values. This changelist does the latter. PiperOrigin-RevId: 311840096 GitOrigin-RevId: f012012ef78234a6a4585321b67d7b7c92ebc266 Change-Id: Ic84886f38ff30d7d72c126e9b63c9a61eb729a1a
5 years ago
// Copyright 2018 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.
//
// -----------------------------------------------------------------------------
// mocking_bit_gen.h
// -----------------------------------------------------------------------------
//
// This file includes an `absl::MockingBitGen` class to use as a mock within the
// Googletest testing framework. Such a mock is useful to provide deterministic
// values as return values within (otherwise random) Abseil distribution
// functions. Such determinism within a mock is useful within testing frameworks
// to test otherwise indeterminate APIs.
//
// More information about the Googletest testing framework is available at
// https://github.com/google/googletest
#ifndef ABSL_RANDOM_MOCKING_BIT_GEN_H_
#define ABSL_RANDOM_MOCKING_BIT_GEN_H_
#include <iterator>
#include <limits>
#include <memory>
#include <tuple>
#include <type_traits>
#include <typeindex>
#include <typeinfo>
#include <utility>
#include "gmock/gmock.h"
#include "gtest/gtest.h"
#include "absl/container/flat_hash_map.h"
#include "absl/meta/type_traits.h"
#include "absl/random/distributions.h"
#include "absl/random/internal/distribution_caller.h"
#include "absl/random/internal/mocking_bit_gen_base.h"
#include "absl/strings/str_cat.h"
#include "absl/strings/str_join.h"
#include "absl/types/span.h"
#include "absl/types/variant.h"
#include "absl/utility/utility.h"
namespace absl {
ABSL_NAMESPACE_BEGIN
namespace random_internal {
template <typename, typename>
struct MockSingleOverload;
} // namespace random_internal
// MockingBitGen
//
// `absl::MockingBitGen` is a mock Uniform Random Bit Generator (URBG) class
// which can act in place of an `absl::BitGen` URBG within tests using the
// Googletest testing framework.
//
// Usage:
//
// Use an `absl::MockingBitGen` along with a mock distribution object (within
// mock_distributions.h) inside Googletest constructs such as ON_CALL(),
// EXPECT_TRUE(), etc. to produce deterministic results conforming to the
// distribution's API contract.
//
// Example:
//
// // Mock a call to an `absl::Bernoulli` distribution using Googletest
// absl::MockingBitGen bitgen;
//
// ON_CALL(absl::MockBernoulli(), Call(bitgen, 0.5))
// .WillByDefault(testing::Return(true));
// EXPECT_TRUE(absl::Bernoulli(bitgen, 0.5));
//
// // Mock a call to an `absl::Uniform` distribution within Googletest
// absl::MockingBitGen bitgen;
//
// ON_CALL(absl::MockUniform<int>(), Call(bitgen, testing::_, testing::_))
// .WillByDefault([] (int low, int high) {
// return (low + high) / 2;
// });
//
// EXPECT_EQ(absl::Uniform<int>(gen, 0, 10), 5);
// EXPECT_EQ(absl::Uniform<int>(gen, 30, 40), 35);
//
// At this time, only mock distributions supplied within the Abseil random
// library are officially supported.
//
class MockingBitGen : public absl::random_internal::MockingBitGenBase {
public:
MockingBitGen() {}
~MockingBitGen() override {
for (const auto& del : deleters_) del();
}
private:
template <typename DistrT, typename... Args>
using MockFnType =
::testing::MockFunction<typename DistrT::result_type(Args...)>;
// MockingBitGen::Register
//
// Register<DistrT, FormatT, ArgTupleT> is the main extension point for
// extending the MockingBitGen framework. It provides a mechanism to install a
// mock expectation for the distribution `distr_t` onto the MockingBitGen
// context.
//
// The returned MockFunction<...> type can be used to setup additional
// distribution parameters of the expectation.
template <typename DistrT, typename... Args, typename... Ms>
decltype(std::declval<MockFnType<DistrT, Args...>>().gmock_Call(
std::declval<Ms>()...))
Register(Ms&&... matchers) {
auto& mock =
mocks_[std::type_index(GetTypeId<DistrT, std::tuple<Args...>>())];
if (!mock.mock_fn) {
auto* mock_fn = new MockFnType<DistrT, Args...>;
mock.mock_fn = mock_fn;
mock.match_impl = &MatchImpl<DistrT, Args...>;
deleters_.emplace_back([mock_fn] { delete mock_fn; });
}
return static_cast<MockFnType<DistrT, Args...>*>(mock.mock_fn)
->gmock_Call(std::forward<Ms>(matchers)...);
}
mutable std::vector<std::function<void()>> deleters_;
using match_impl_fn = void (*)(void* mock_fn, void* t_erased_dist_args,
void* t_erased_result);
struct MockData {
void* mock_fn = nullptr;
match_impl_fn match_impl = nullptr;
};
mutable absl::flat_hash_map<std::type_index, MockData> mocks_;
template <typename DistrT, typename... Args>
static void MatchImpl(void* mock_fn, void* dist_args, void* result) {
using result_type = typename DistrT::result_type;
*static_cast<result_type*>(result) = absl::apply(
[mock_fn](Args... args) -> result_type {
return (*static_cast<MockFnType<DistrT, Args...>*>(mock_fn))
.Call(std::move(args)...);
},
*static_cast<std::tuple<Args...>*>(dist_args));
}
// Looks for an appropriate mock - Returns the mocked result if one is found.
// Otherwise, returns a random value generated by the underlying URBG.
bool CallImpl(const std::type_info& key_type, void* dist_args,
void* result) override {
// Trigger a mock, if there exists one that matches `param`.
auto it = mocks_.find(std::type_index(key_type));
if (it == mocks_.end()) return false;
auto* mock_data = static_cast<MockData*>(&it->second);
mock_data->match_impl(mock_data->mock_fn, dist_args, result);
return true;
}
template <typename, typename>
friend struct ::absl::random_internal::MockSingleOverload;
friend struct ::absl::random_internal::DistributionCaller<
absl::MockingBitGen>;
};
// -----------------------------------------------------------------------------
// Implementation Details Only Below
// -----------------------------------------------------------------------------
namespace random_internal {
template <>
struct DistributionCaller<absl::MockingBitGen> {
template <typename DistrT, typename... Args>
static typename DistrT::result_type Call(absl::MockingBitGen* gen,
Args&&... args) {
return gen->template Call<DistrT>(std::forward<Args>(args)...);
}
};
} // namespace random_internal
ABSL_NAMESPACE_END
} // namespace absl
#endif // ABSL_RANDOM_MOCKING_BIT_GEN_H_