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authorGravatar Abseil Team <absl-team@google.com>2020-06-11 09:56:29 -0700
committerGravatar vslashg <gfalcon@google.com>2020-06-12 17:24:49 -0400
commit2c92bdc7c2f8e65198af61a0611d90a55312ee82 (patch)
tree8b0fe283dd1594d6bd8f4d039417047807985f97 /absl/random/internal/mock_helpers.h
parente7ebf9803746b9a115d96164bdf5e915be8f223b (diff)
Export of internal Abseil changes
-- e21e960918678629abf89ad1b694b7d4a456b434 by Greg Falcon <gfalcon@google.com>: Roll back invoke() change due to large increases in compiler memory usage. PiperOrigin-RevId: 315919455 -- f95872e1e1d7afdefbac94f42ea228d42d80eb6e by Greg Falcon <gfalcon@google.com>: Rollback of invoke() changes due to compiler memory usage growth PiperOrigin-RevId: 315911585 -- 6c6c6ba6892016a2ce4703042800254fb9b15727 by Laramie Leavitt <lar@google.com>: Move some of the common mocking code into MockHelpers. Use MockHelpers to do mock signature detection and improve the dispatch mechansim. PiperOrigin-RevId: 315825988 -- 5e9380367d280c7fa6dbd4d0f48c31ade7f1d419 by Greg Falcon <gfalcon@google.com>: Rename the internal implementation details Invoke and InvokeT to `invoke` and `invoke_result_t`, since these are re-implementations of C++17 library entites of the same names. PiperOrigin-RevId: 315790467 GitOrigin-RevId: e21e960918678629abf89ad1b694b7d4a456b434 Change-Id: Ia75011f94cb033c1c9a4cb64cf14d283b91426ac
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+//
+// Copyright 2019 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.
+
+#ifndef ABSL_RANDOM_INTERNAL_MOCK_HELPERS_H_
+#define ABSL_RANDOM_INTERNAL_MOCK_HELPERS_H_
+
+#include <tuple>
+#include <type_traits>
+
+#include "absl/base/internal/fast_type_id.h"
+#include "absl/types/optional.h"
+
+namespace absl {
+ABSL_NAMESPACE_BEGIN
+namespace random_internal {
+
+// MockHelpers works in conjunction with MockOverloadSet, MockingBitGen, and
+// BitGenRef to enable the mocking capability for absl distribution functions.
+//
+// MockingBitGen registers mocks based on the typeid of a mock signature, KeyT,
+// which is used to generate a unique id.
+//
+// KeyT is a signature of the form:
+// result_type(discriminator_type, std::tuple<args...>)
+// The mocked function signature will be composed from KeyT as:
+// result_type(args...)
+//
+class MockHelpers {
+ using IdType = ::absl::base_internal::FastTypeIdType;
+
+ // Given a key signature type used to index the mock, extract the components.
+ // KeyT is expected to have the form:
+ // result_type(discriminator_type, arg_tuple_type)
+ template <typename KeyT>
+ struct KeySignature;
+
+ template <typename ResultT, typename DiscriminatorT, typename ArgTupleT>
+ struct KeySignature<ResultT(DiscriminatorT, ArgTupleT)> {
+ using result_type = ResultT;
+ using discriminator_type = DiscriminatorT;
+ using arg_tuple_type = ArgTupleT;
+ };
+
+ // Detector for InvokeMock.
+ template <class T>
+ using invoke_mock_t = decltype(std::declval<T*>()->InvokeMock(
+ std::declval<IdType>(), std::declval<void*>(), std::declval<void*>()));
+
+ // Empty implementation of InvokeMock.
+ template <typename KeyT, typename ReturnT, typename ArgTupleT, typename URBG,
+ typename... Args>
+ static absl::optional<ReturnT> InvokeMockImpl(char, URBG*, Args&&...) {
+ return absl::nullopt;
+ }
+
+ // Non-empty implementation of InvokeMock.
+ template <typename KeyT, typename ReturnT, typename ArgTupleT, typename URBG,
+ typename = invoke_mock_t<URBG>, typename... Args>
+ static absl::optional<ReturnT> InvokeMockImpl(int, URBG* urbg,
+ Args&&... args) {
+ ArgTupleT arg_tuple(std::forward<Args>(args)...);
+ ReturnT result;
+ if (urbg->InvokeMock(::absl::base_internal::FastTypeId<KeyT>(), &arg_tuple,
+ &result)) {
+ return result;
+ }
+ return absl::nullopt;
+ }
+
+ public:
+ // Invoke a mock for the KeyT (may or may not be a signature).
+ //
+ // KeyT is used to generate a typeid-based lookup key for the mock.
+ // KeyT is a signature of the form:
+ // result_type(discriminator_type, std::tuple<args...>)
+ // The mocked function signature will be composed from KeyT as:
+ // result_type(args...)
+ //
+ // An instance of arg_tuple_type must be constructable from Args..., since
+ // the underlying mechanism requires a pointer to an argument tuple.
+ template <typename KeyT, typename URBG, typename... Args>
+ static auto MaybeInvokeMock(URBG* urbg, Args&&... args)
+ -> absl::optional<typename KeySignature<KeyT>::result_type> {
+ // Use function overloading to dispatch to the implemenation since
+ // more modern patterns (e.g. require + constexpr) are not supported in all
+ // compiler configurations.
+ return InvokeMockImpl<KeyT, typename KeySignature<KeyT>::result_type,
+ typename KeySignature<KeyT>::arg_tuple_type, URBG>(
+ 0, urbg, std::forward<Args>(args)...);
+ }
+
+ // Acquire a mock for the KeyT (may or may not be a signature).
+ //
+ // KeyT is used to generate a typeid-based lookup for the mock.
+ // KeyT is a signature of the form:
+ // result_type(discriminator_type, std::tuple<args...>)
+ // The mocked function signature will be composed from KeyT as:
+ // result_type(args...)
+ template <typename KeyT, typename MockURBG>
+ static auto MockFor(MockURBG& m) -> decltype(
+ std::declval<MockURBG>()
+ .template RegisterMock<typename KeySignature<KeyT>::result_type,
+ typename KeySignature<KeyT>::arg_tuple_type>(
+ std::declval<IdType>())) {
+ return m.template RegisterMock<typename KeySignature<KeyT>::result_type,
+ typename KeySignature<KeyT>::arg_tuple_type>(
+ ::absl::base_internal::FastTypeId<KeyT>());
+ }
+};
+
+} // namespace random_internal
+ABSL_NAMESPACE_END
+} // namespace absl
+
+#endif // ABSL_RANDOM_INTERNAL_MOCK_HELPERS_H_