Merge changes I0ab600cd,I1e74c64a am: 798f3afdf6 am: 2f9c4b2c3b am: a9167328fc am: 7563023510 am: 43d8f56cdcandroid-13.0.0_r83android-13.0.0_r82android-13.0.0_r81android-13.0.0_r80android-13.0.0_r79android-13.0.0_r78android-13.0.0_r77android-13.0.0_r76android-13.0.0_r75android-13.0.0_r74android-13.0.0_r73android-13.0.0_r72android-13.0.0_r71android-13.0.0_r70android-13.0.0_r69android-13.0.0_r68android-13.0.0_r67android-13.0.0_r66android-13.0.0_r65android-13.0.0_r64android-13.0.0_r63android-13.0.0_r62android-13.0.0_r61android-13.0.0_r60android-13.0.0_r59android-13.0.0_r58android-13.0.0_r56android-13.0.0_r54android-13.0.0_r53android-13.0.0_r52android-13.0.0_r51android-13.0.0_r50android-13.0.0_r49android-13.0.0_r48android-13.0.0_r47android-13.0.0_r46android-13.0.0_r45android-13.0.0_r44android-13.0.0_r43android-13.0.0_r42android-13.0.0_r41android-13.0.0_r40android-13.0.0_r39android-13.0.0_r38android-13.0.0_r37android-13.0.0_r36android-13.0.0_r35android-13.0.0_r34android-13.0.0_r33android-13.0.0_r32android13-qpr3-s9-releaseandroid13-qpr3-s8-releaseandroid13-qpr3-s7-releaseandroid13-qpr3-s6-releaseandroid13-qpr3-s5-releaseandroid13-qpr3-s4-releaseandroid13-qpr3-s3-releaseandroid13-qpr3-s2-releaseandroid13-qpr3-s14-releaseandroid13-qpr3-s13-releaseandroid13-qpr3-s12-releaseandroid13-qpr3-s11-releaseandroid13-qpr3-s10-releaseandroid13-qpr3-s1-releaseandroid13-qpr3-releaseandroid13-qpr3-c-s8-releaseandroid13-qpr3-c-s7-releaseandroid13-qpr3-c-s6-releaseandroid13-qpr3-c-s5-releaseandroid13-qpr3-c-s4-releaseandroid13-qpr3-c-s3-releaseandroid13-qpr3-c-s2-releaseandroid13-qpr3-c-s12-releaseandroid13-qpr3-c-s11-releaseandroid13-qpr3-c-s10-releaseandroid13-qpr3-c-s1-releaseandroid13-qpr2-s9-releaseandroid13-qpr2-s8-releaseandroid13-qpr2-s7-releaseandroid13-qpr2-s6-releaseandroid13-qpr2-s5-releaseandroid13-qpr2-s3-releaseandroid13-qpr2-s2-releaseandroid13-qpr2-s12-releaseandroid13-qpr2-s11-releaseandroid13-qpr2-s10-releaseandroid13-qpr2-s1-releaseandroid13-qpr2-releaseandroid13-qpr2-b-s1-releaseandroid13-d4-s2-releaseandroid13-d4-s1-releaseandroid13-d4-release

Original change: https://android-review.googlesource.com/c/platform/external/webrtc/+/2062410

Change-Id: I1aa9f459b825711b800cc65782979943a9151ec7
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>

1 files changed, 116 insertions, 0 deletions

diff --git a/third_party/abseil-cpp/absl/flags/internal/flag_msvc.inc b/third_party/abseil-cpp/absl/flags/internal/flag_msvc.inc
new file mode 100644
index 0000000000..c31bd27fd8
--- /dev/null
+++ b/third_party/abseil-cpp/absl/flags/internal/flag_msvc.inc
@@ -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.
+
+// Do not include this file directly.
+// Include absl/flags/flag.h instead.
+
+// MSVC debug builds do not implement initialization with constexpr constructors
+// correctly. To work around this we add a level of indirection, so that the
+// class `absl::Flag` contains an `internal::Flag*` (instead of being an alias
+// to that class) and dynamically allocates an instance when necessary. We also
+// forward all calls to internal::Flag methods via trampoline methods. In this
+// setup the `absl::Flag` class does not have constructor and virtual methods,
+// all the data members are public and thus MSVC is able to initialize it at
+// link time. To deal with multiple threads accessing the flag for the first
+// time concurrently we use an atomic boolean indicating if flag object is
+// initialized. We also employ the double-checked locking pattern where the
+// second level of protection is a global Mutex, so if two threads attempt to
+// construct the flag concurrently only one wins.
+//
+// This solution is based on a recomendation here:
+// https://developercommunity.visualstudio.com/content/problem/336946/class-with-constexpr-constructor-not-using-static.html?childToView=648454#comment-648454
+
+namespace flags_internal {
+absl::Mutex* GetGlobalConstructionGuard();
+}  // namespace flags_internal
+
+// Public methods of `absl::Flag<T>` are NOT part of the Abseil Flags API.
+// See https://abseil.io/docs/cpp/guides/flags
+template <typename T>
+class Flag {
+ public:
+  // No constructor and destructor to ensure this is an aggregate type.
+  // Visual Studio 2015 still requires the constructor for class to be
+  // constexpr initializable.
+#if _MSC_VER <= 1900
+  constexpr Flag(const char* name, const char* filename,
+                 const flags_internal::HelpGenFunc help_gen,
+                 const flags_internal::FlagDfltGenFunc default_value_gen)
+      : name_(name),
+        filename_(filename),
+        help_gen_(help_gen),
+        default_value_gen_(default_value_gen),
+        inited_(false),
+        impl_(nullptr) {}
+#endif
+
+  flags_internal::Flag<T>& GetImpl() const {
+    if (!inited_.load(std::memory_order_acquire)) {
+      absl::MutexLock l(flags_internal::GetGlobalConstructionGuard());
+
+      if (inited_.load(std::memory_order_acquire)) {
+        return *impl_;
+      }
+
+      impl_ = new flags_internal::Flag<T>(
+          name_, filename_,
+          {flags_internal::FlagHelpMsg(help_gen_),
+           flags_internal::FlagHelpKind::kGenFunc},
+          {flags_internal::FlagDefaultSrc(default_value_gen_),
+           flags_internal::FlagDefaultKind::kGenFunc});
+      inited_.store(true, std::memory_order_release);
+    }
+
+    return *impl_;
+  }
+
+  // Public methods of `absl::Flag<T>` are NOT part of the Abseil Flags API.
+  // See https://abseil.io/docs/cpp/guides/flags
+  bool IsRetired() const { return GetImpl().IsRetired(); }
+  absl::string_view Name() const { return GetImpl().Name(); }
+  std::string Help() const { return GetImpl().Help(); }
+  bool IsModified() const { return GetImpl().IsModified(); }
+  bool IsSpecifiedOnCommandLine() const {
+    return GetImpl().IsSpecifiedOnCommandLine();
+  }
+  std::string Filename() const { return GetImpl().Filename(); }
+  std::string DefaultValue() const { return GetImpl().DefaultValue(); }
+  std::string CurrentValue() const { return GetImpl().CurrentValue(); }
+  template <typename U>
+  inline bool IsOfType() const {
+    return GetImpl().template IsOfType<U>();
+  }
+  T Get() const {
+    return flags_internal::FlagImplPeer::InvokeGet<T>(GetImpl());
+  }
+  void Set(const T& v) {
+    flags_internal::FlagImplPeer::InvokeSet(GetImpl(), v);
+  }
+  void InvokeCallback() { GetImpl().InvokeCallback(); }
+
+  const CommandLineFlag& Reflect() const {
+    return flags_internal::FlagImplPeer::InvokeReflect(GetImpl());
+  }
+
+  // The data members are logically private, but they need to be public for
+  // this to be an aggregate type.
+  const char* name_;
+  const char* filename_;
+  const flags_internal::HelpGenFunc help_gen_;
+  const flags_internal::FlagDfltGenFunc default_value_gen_;
+
+  mutable std::atomic<bool> inited_;
+  mutable flags_internal::Flag<T>* impl_;
+};