Squashed 'third_party/abseil_cpp/' changes from 768eb2ca2..ccdbb5941

ccdbb5941 Export of internal Abseil changes
01f5f81f9 Export of internal Abseil changes
2c92bdc7c Export of internal Abseil changes
e7ebf9803 Export of internal Abseil changes
2eba343b5 Export of internal Abseil changes
a8b03d90e Export of internal Abseil changes
1d31b5c36 Export of internal Abseil changes
da3a87690 Export of internal Abseil changes
8faf20461 Exclude empty directories (#697)
2069dc796 Export of internal Abseil changes
4832bf6bf Added a BUILD file in root to expose license. (#695)
af8f994af Export of internal Abseil changes
33caf1097 Export of internal Abseil changes
cf1a02e2d Export of internal Abseil changes

git-subtree-dir: third_party/abseil_cpp
git-subtree-split: ccdbb5941f992fabda7eae3ce72f55efc17c826a

1 files changed, 26 insertions, 22 deletions

diff --git a/absl/flags/internal/flag.cc b/absl/flags/internal/flag.cc
index 96c026dcb5d2..1502e7f11d36 100644
--- a/absl/flags/internal/flag.cc
+++ b/absl/flags/internal/flag.cc
@@ -15,22 +15,26 @@
 
 #include "absl/flags/internal/flag.h"
 
+#include <assert.h>
 #include <stddef.h>
 #include <stdint.h>
 #include <string.h>
 
+#include <array>
 #include <atomic>
 #include <memory>
+#include <new>
 #include <string>
-#include <vector>
+#include <typeinfo>
 
-#include "absl/base/attributes.h"
+#include "absl/base/call_once.h"
 #include "absl/base/casts.h"
 #include "absl/base/config.h"
-#include "absl/base/const_init.h"
 #include "absl/base/optimization.h"
+#include "absl/flags/config.h"
 #include "absl/flags/internal/commandlineflag.h"
 #include "absl/flags/usage_config.h"
+#include "absl/memory/memory.h"
 #include "absl/strings/str_cat.h"
 #include "absl/strings/string_view.h"
 #include "absl/synchronization/mutex.h"
@@ -63,14 +67,14 @@ bool ShouldValidateFlagValue(FlagFastTypeId flag_type_id) {
 // need to acquire these locks themselves.
 class MutexRelock {
  public:
-  explicit MutexRelock(absl::Mutex* mu) : mu_(mu) { mu_->Unlock(); }
-  ~MutexRelock() { mu_->Lock(); }
+  explicit MutexRelock(absl::Mutex& mu) : mu_(mu) { mu_.Unlock(); }
+  ~MutexRelock() { mu_.Lock(); }
 
   MutexRelock(const MutexRelock&) = delete;
   MutexRelock& operator=(const MutexRelock&) = delete;
 
  private:
-  absl::Mutex* mu_;
+  absl::Mutex& mu_;
 };
 
 }  // namespace
@@ -83,7 +87,7 @@ class FlagImpl;
 class FlagState : public flags_internal::FlagStateInterface {
  public:
   template <typename V>
-  FlagState(FlagImpl* flag_impl, const V& v, bool modified,
+  FlagState(FlagImpl& flag_impl, const V& v, bool modified,
             bool on_command_line, int64_t counter)
       : flag_impl_(flag_impl),
         value_(v),
@@ -92,9 +96,9 @@ class FlagState : public flags_internal::FlagStateInterface {
         counter_(counter) {}
 
   ~FlagState() override {
-    if (flag_impl_->ValueStorageKind() != FlagValueStorageKind::kAlignedBuffer)
+    if (flag_impl_.ValueStorageKind() != FlagValueStorageKind::kAlignedBuffer)
       return;
-    flags_internal::Delete(flag_impl_->op_, value_.heap_allocated);
+    flags_internal::Delete(flag_impl_.op_, value_.heap_allocated);
   }
 
  private:
@@ -102,15 +106,15 @@ class FlagState : public flags_internal::FlagStateInterface {
 
   // Restores the flag to the saved state.
   void Restore() const override {
-    if (!flag_impl_->RestoreState(*this)) return;
+    if (!flag_impl_.RestoreState(*this)) return;
 
-    ABSL_INTERNAL_LOG(
-        INFO, absl::StrCat("Restore saved value of ", flag_impl_->Name(),
-                           " to: ", flag_impl_->CurrentValue()));
+    ABSL_INTERNAL_LOG(INFO,
+                      absl::StrCat("Restore saved value of ", flag_impl_.Name(),
+                                   " to: ", flag_impl_.CurrentValue()));
   }
 
   // Flag and saved flag data.
-  FlagImpl* flag_impl_;
+  FlagImpl& flag_impl_;
   union SavedValue {
     explicit SavedValue(void* v) : heap_allocated(v) {}
     explicit SavedValue(int64_t v) : one_word(v) {}
@@ -327,7 +331,7 @@ void FlagImpl::InvokeCallback() const {
   // and it also can be different by the time the callback invocation is
   // completed. Requires that *primary_lock be held in exclusive mode; it may be
   // released and reacquired by the implementation.
-  MutexRelock relock(DataGuard());
+  MutexRelock relock(*DataGuard());
   absl::MutexLock lock(&callback_->guard);
   cb();
 }
@@ -340,17 +344,17 @@ std::unique_ptr<FlagStateInterface> FlagImpl::SaveState() {
   switch (ValueStorageKind()) {
     case FlagValueStorageKind::kAlignedBuffer: {
       return absl::make_unique<FlagState>(
-          this, flags_internal::Clone(op_, AlignedBufferValue()), modified,
+          *this, flags_internal::Clone(op_, AlignedBufferValue()), modified,
           on_command_line, counter_);
     }
     case FlagValueStorageKind::kOneWordAtomic: {
       return absl::make_unique<FlagState>(
-          this, OneWordValue().load(std::memory_order_acquire), modified,
+          *this, OneWordValue().load(std::memory_order_acquire), modified,
           on_command_line, counter_);
     }
     case FlagValueStorageKind::kTwoWordsAtomic: {
       return absl::make_unique<FlagState>(
-          this, TwoWordsValue().load(std::memory_order_acquire), modified,
+          *this, TwoWordsValue().load(std::memory_order_acquire), modified,
           on_command_line, counter_);
     }
   }
@@ -411,14 +415,14 @@ std::atomic<AlignedTwoWords>& FlagImpl::TwoWordsValue() const {
 // parsed value. In case if any error is encountered in either step, the error
 // message is stored in 'err'
 std::unique_ptr<void, DynValueDeleter> FlagImpl::TryParse(
-    absl::string_view value, std::string* err) const {
+    absl::string_view value, std::string& err) const {
   std::unique_ptr<void, DynValueDeleter> tentative_value = MakeInitValue();
 
   std::string parse_err;
   if (!flags_internal::Parse(op_, value, tentative_value.get(), &parse_err)) {
     absl::string_view err_sep = parse_err.empty() ? "" : "; ";
-    *err = absl::StrCat("Illegal value '", value, "' specified for flag '",
-                        Name(), "'", err_sep, parse_err);
+    err = absl::StrCat("Illegal value '", value, "' specified for flag '",
+                       Name(), "'", err_sep, parse_err);
     return nullptr;
   }
 
@@ -474,7 +478,7 @@ void FlagImpl::Write(const void* src) {
 //  * Update the current flag value if it was never set before
 // The mode is selected based on 'set_mode' parameter.
 bool FlagImpl::ParseFrom(absl::string_view value, FlagSettingMode set_mode,
-                         ValueSource source, std::string* err) {
+                         ValueSource source, std::string& err) {
   absl::MutexLock l(DataGuard());
 
   switch (set_mode) {