Export of internal Abseil changes.

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1edfe05ddddca43e7650b2d790df7c8498c0e588 by Abseil Team <absl-team@google.com>:

Adding an assert to catch various misuses of std::optional.

PiperOrigin-RevId: 249427865

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45463bbb7e59dfbc584b2f024368a63db98bd7a8 by CJ Johnson <johnsoncj@google.com>:

Migrates internal member function GetAllocator() to GetAllocPtr() and changes the return type to pointer instead of reference to avoid unnecessary copy in DestroyElements(...)

PiperOrigin-RevId: 249319571

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507835be22af85676143ee0c43a80a52bc32094c by Abseil Team <absl-team@google.com>:

Fix -Wstring-conversion in GetEnvVar (Windows implementation).

PiperOrigin-RevId: 249201897
GitOrigin-RevId: 1edfe05ddddca43e7650b2d790df7c8498c0e588
Change-Id: I9300131887ee507cf80d399c724cf87341e4f11a

absl/container/inlined_vector.h

@@ -155,7 +155,7 @@ class InlinedVector {
 
   // Creates a copy of an `other` inlined vector using `other`'s allocator.
   InlinedVector(const InlinedVector& other)
-      : InlinedVector(other, other.storage_.GetAllocator()) {}
+      : InlinedVector(other, *other.storage_.GetAllocPtr()) {}
 
   // Creates a copy of an `other` inlined vector using a specified allocator.
   InlinedVector(const InlinedVector& other, const allocator_type& alloc)
@@ -189,7 +189,7 @@ class InlinedVector {
   InlinedVector(InlinedVector&& other) noexcept(
       absl::allocator_is_nothrow<allocator_type>::value ||
       std::is_nothrow_move_constructible<value_type>::value)
-      : storage_(other.storage_.GetAllocator()) {
+      : storage_(*other.storage_.GetAllocPtr()) {
     if (other.storage_.GetIsAllocated()) {
       // We can just steal the underlying buffer from the source.
       // That leaves the source empty, so we clear its size.
@@ -224,7 +224,7 @@ class InlinedVector {
       absl::allocator_is_nothrow<allocator_type>::value)
       : storage_(alloc) {
     if (other.storage_.GetIsAllocated()) {
-      if (alloc == other.storage_.GetAllocator()) {
+      if (*storage_.GetAllocPtr() == *other.storage_.GetAllocPtr()) {
         // We can just steal the allocation from the source.
         storage_.SetAllocatedSize(other.size());
         storage_.SetAllocatedData(other.storage_.GetAllocatedData());
@@ -437,7 +437,7 @@ class InlinedVector {
   // `InlinedVector::get_allocator()`
   //
   // Returns a copy of the allocator of the inlined vector.
-  allocator_type get_allocator() const { return storage_.GetAllocator(); }
+  allocator_type get_allocator() const { return *storage_.GetAllocPtr(); }
 
   // ---------------------------------------------------------------------------
   // InlinedVector Member Mutators
@@ -794,19 +794,15 @@ class InlinedVector {
   // deallocates the heap allocation if the inlined vector was allocated.
   void clear() noexcept {
     const bool is_allocated = storage_.GetIsAllocated();
-
     pointer the_data =
         is_allocated ? storage_.GetAllocatedData() : storage_.GetInlinedData();
-
+    inlined_vector_internal::DestroyElements(storage_.GetAllocPtr(), the_data,
-    inlined_vector_internal::DestroyElements(storage_.GetAllocator(), the_data,
                                              storage_.GetSize());
-
+    storage_.SetInlinedSize(0);
     if (is_allocated) {
-      AllocatorTraits::deallocate(storage_.GetAllocator(), the_data,
+      AllocatorTraits::deallocate(*storage_.GetAllocPtr(), the_data,
                                   storage_.GetAllocatedCapacity());
     }
-
-    storage_.SetInlinedSize(/* size = */ 0);
   }
 
   // `InlinedVector::reserve()`
@@ -854,7 +850,7 @@ class InlinedVector {
     // Reallocate storage and move elements.
     // We can't simply use the same approach as above, because `assign()` would
     // call into `reserve()` internally and reserve larger capacity than we need
-    pointer new_data = AllocatorTraits::allocate(storage_.GetAllocator(), s);
+    pointer new_data = AllocatorTraits::allocate(*storage_.GetAllocPtr(), s);
     UninitializedCopy(std::make_move_iterator(storage_.GetAllocatedData()),
                       std::make_move_iterator(storage_.GetAllocatedData() + s),
                       new_data);
@@ -880,7 +876,7 @@ class InlinedVector {
       Destroy(storage_.GetAllocatedData(),
               storage_.GetAllocatedData() + size());
       assert(begin() == storage_.GetAllocatedData());
-      AllocatorTraits::deallocate(storage_.GetAllocator(),
+      AllocatorTraits::deallocate(*storage_.GetAllocPtr(),
                                   storage_.GetAllocatedData(),
                                   storage_.GetAllocatedCapacity());
     } else {
@@ -895,7 +891,7 @@ class InlinedVector {
   template <typename... Args>
   reference Construct(pointer p, Args&&... args) {
     std::allocator_traits<allocator_type>::construct(
-        storage_.GetAllocator(), p, std::forward<Args>(args)...);
+        *storage_.GetAllocPtr(), p, std::forward<Args>(args)...);
     return *p;
   }
 
@@ -912,7 +908,7 @@ class InlinedVector {
   // Destroy [`from`, `to`) in place.
   void Destroy(pointer from, pointer to) {
     for (pointer cur = from; cur != to; ++cur) {
-      std::allocator_traits<allocator_type>::destroy(storage_.GetAllocator(),
+      std::allocator_traits<allocator_type>::destroy(*storage_.GetAllocPtr(),
                                                      cur);
     }
 #if !defined(NDEBUG)
@@ -943,7 +939,7 @@ class InlinedVector {
     }
 
     pointer new_data =
-        AllocatorTraits::allocate(storage_.GetAllocator(), new_capacity);
+        AllocatorTraits::allocate(*storage_.GetAllocPtr(), new_capacity);
 
     UninitializedCopy(std::make_move_iterator(data()),
                       std::make_move_iterator(data() + s), new_data);
@@ -975,7 +971,7 @@ class InlinedVector {
       // Move everyone into the new allocation, leaving a gap of `n` for the
       // requested shift.
       pointer new_data =
-          AllocatorTraits::allocate(storage_.GetAllocator(), new_capacity);
+          AllocatorTraits::allocate(*storage_.GetAllocPtr(), new_capacity);
       size_type index = position - begin();
       UninitializedCopy(std::make_move_iterator(data()),
                         std::make_move_iterator(data() + index), new_data);
@@ -1024,7 +1020,7 @@ class InlinedVector {
 
     size_type new_capacity = 2 * capacity();
     pointer new_data =
-        AllocatorTraits::allocate(storage_.GetAllocator(), new_capacity);
+        AllocatorTraits::allocate(*storage_.GetAllocPtr(), new_capacity);
 
     reference new_element =
         Construct(new_data + s, std::forward<Args>(args)...);
@@ -1038,7 +1034,7 @@ class InlinedVector {
 
   void InitAssign(size_type n) {
     if (n > static_cast<size_type>(N)) {
-      pointer new_data = AllocatorTraits::allocate(storage_.GetAllocator(), n);
+      pointer new_data = AllocatorTraits::allocate(*storage_.GetAllocPtr(), n);
       storage_.SetAllocatedData(new_data);
       storage_.SetAllocatedCapacity(n);
       UninitializedFill(storage_.GetAllocatedData(),
@@ -1053,7 +1049,7 @@ class InlinedVector {
 
   void InitAssign(size_type n, const_reference v) {
     if (n > static_cast<size_type>(N)) {
-      pointer new_data = AllocatorTraits::allocate(storage_.GetAllocator(), n);
+      pointer new_data = AllocatorTraits::allocate(*storage_.GetAllocPtr(), n);
       storage_.SetAllocatedData(new_data);
       storage_.SetAllocatedCapacity(n);
       UninitializedFill(storage_.GetAllocatedData(),
@@ -1126,7 +1122,7 @@ class InlinedVector {
       // Both out of line, so just swap the tag, allocation, and allocator.
       storage_.SwapSizeAndIsAllocated(std::addressof(other.storage_));
       storage_.SwapAllocatedSizeAndCapacity(std::addressof(other.storage_));
-      swap(storage_.GetAllocator(), other.storage_.GetAllocator());
+      swap(*storage_.GetAllocPtr(), *other.storage_.GetAllocPtr());
 
       return;
     }
@@ -1156,7 +1152,7 @@ class InlinedVector {
                  a->storage_.GetInlinedData() + a_size);
 
       storage_.SwapSizeAndIsAllocated(std::addressof(other.storage_));
-      swap(storage_.GetAllocator(), other.storage_.GetAllocator());
+      swap(*storage_.GetAllocPtr(), *other.storage_.GetAllocPtr());
 
       assert(b->size() == a_size);
       assert(a->size() == b_size);
@@ -1198,8 +1194,8 @@ class InlinedVector {
     a->storage_.SetAllocatedData(b_data);
     a->storage_.SetAllocatedCapacity(b_capacity);
 
-    if (a->storage_.GetAllocator() != b->storage_.GetAllocator()) {
+    if (*a->storage_.GetAllocPtr() != *b->storage_.GetAllocPtr()) {
-      swap(a->storage_.GetAllocator(), b->storage_.GetAllocator());
+      swap(*a->storage_.GetAllocPtr(), *b->storage_.GetAllocPtr());
     }
 
     assert(b->size() == a_size);

absl/container/internal/inlined_vector.h

@@ -33,7 +33,7 @@ using IsAtLeastForwardIterator = std::is_convertible<
     std::forward_iterator_tag>;
 
 template <typename AllocatorType, typename ValueType, typename SizeType>
-void DestroyElements(AllocatorType alloc, ValueType* destroy_first,
+void DestroyElements(AllocatorType* alloc_ptr, ValueType* destroy_first,
                      SizeType destroy_size) {
   using AllocatorTraits = std::allocator_traits<AllocatorType>;
 
@@ -45,7 +45,7 @@ void DestroyElements(AllocatorType alloc, ValueType* destroy_first,
   // NOTE: We assume destructors do not throw and thus make no attempt to roll
   // back.
   for (SizeType i = 0; i < destroy_size; ++i) {
-    AllocatorTraits::destroy(alloc, destroy_first + i);
+    AllocatorTraits::destroy(*alloc_ptr, destroy_first + i);
   }
 
 #ifndef NDEBUG
@@ -104,10 +104,12 @@ class Storage {
     return data_.allocated.allocated_capacity;
   }
 
-  allocator_type& GetAllocator() { return metadata_.template get<0>(); }
+  allocator_type* GetAllocPtr() {
+    return std::addressof(metadata_.template get<0>());
+  }
 
-  const allocator_type& GetAllocator() const {
+  const allocator_type* GetAllocPtr() const {
-    return metadata_.template get<0>();
+    return std::addressof(metadata_.template get<0>());
   }
 
   void SetAllocatedSize(size_type size) {

absl/flags/parse.cc

@@ -190,7 +190,7 @@ bool GetEnvVar(const char* var_name, std::string* var_value) {
   char buf[1024];
   auto get_res = GetEnvironmentVariableA(var_name, buf, sizeof(buf));
   if (get_res >= sizeof(buf)) {
-    return "";
+    return false;
   }
 
   if (get_res == 0) {

absl/types/optional.h

@@ -421,7 +421,9 @@ class optional : private optional_internal::optional_data<T>,
   //
   // Accesses the underlying `T` value of an `optional`. If the `optional` is
   // empty, behavior is undefined.
-  constexpr const T& operator*() const & { return reference(); }
+  constexpr const T& operator*() const& {
+    return ABSL_ASSERT(this->engaged_), reference();
+  }
   T& operator*() & {
     assert(this->engaged_);
     return reference();