| // Copyright (c) 2012 The Chromium Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. |
| |
| #ifndef QUICHE_COMMON_QUICHE_BUFFER_ALLOCATOR_H_ |
| #define QUICHE_COMMON_QUICHE_BUFFER_ALLOCATOR_H_ |
| |
| #include <stddef.h> |
| |
| #include <memory> |
| |
| #include "absl/strings/string_view.h" |
| #include "quiche/common/platform/api/quiche_export.h" |
| #include "quiche/common/platform/api/quiche_iovec.h" |
| |
| namespace quiche { |
| |
| // Abstract base class for classes which allocate and delete buffers. |
| class QUICHE_EXPORT_PRIVATE QuicheBufferAllocator { |
| public: |
| virtual ~QuicheBufferAllocator() = default; |
| |
| // Returns or allocates a new buffer of |size|. Never returns null. |
| virtual char* New(size_t size) = 0; |
| |
| // Returns or allocates a new buffer of |size| if |flag_enable| is true. |
| // Otherwise, returns a buffer that is compatible with this class directly |
| // with operator new. Never returns null. |
| virtual char* New(size_t size, bool flag_enable) = 0; |
| |
| // Releases a buffer. |
| virtual void Delete(char* buffer) = 0; |
| |
| // Marks the allocator as being idle. Serves as a hint to notify the allocator |
| // that it should release any resources it's still holding on to. |
| virtual void MarkAllocatorIdle() {} |
| }; |
| |
| // A deleter that can be used to manage ownership of buffers allocated via |
| // QuicheBufferAllocator through std::unique_ptr. |
| class QUICHE_EXPORT_PRIVATE QuicheBufferDeleter { |
| public: |
| explicit QuicheBufferDeleter(QuicheBufferAllocator* allocator) |
| : allocator_(allocator) {} |
| |
| QuicheBufferAllocator* allocator() { return allocator_; } |
| void operator()(char* buffer) { allocator_->Delete(buffer); } |
| |
| private: |
| QuicheBufferAllocator* allocator_; |
| }; |
| |
| using QuicheUniqueBufferPtr = std::unique_ptr<char[], QuicheBufferDeleter>; |
| |
| inline QuicheUniqueBufferPtr MakeUniqueBuffer(QuicheBufferAllocator* allocator, |
| size_t size) { |
| return QuicheUniqueBufferPtr(allocator->New(size), |
| QuicheBufferDeleter(allocator)); |
| } |
| |
| // QuicheUniqueBufferPtr with a length attached to it. Similar to |
| // QuicheMemSlice, except unlike QuicheMemSlice, QuicheBuffer is mutable and is |
| // not platform-specific. Also unlike QuicheMemSlice, QuicheBuffer can be |
| // empty. |
| class QUICHE_EXPORT_PRIVATE QuicheBuffer { |
| public: |
| QuicheBuffer() : buffer_(nullptr, QuicheBufferDeleter(nullptr)), size_(0) {} |
| QuicheBuffer(QuicheBufferAllocator* allocator, size_t size) |
| : buffer_(MakeUniqueBuffer(allocator, size)), size_(size) {} |
| |
| QuicheBuffer(QuicheUniqueBufferPtr buffer, size_t size) |
| : buffer_(std::move(buffer)), size_(size) {} |
| |
| // Make sure the move constructor zeroes out the size field. |
| QuicheBuffer(QuicheBuffer&& other) |
| : buffer_(std::move(other.buffer_)), size_(other.size_) { |
| other.buffer_ = nullptr; |
| other.size_ = 0; |
| } |
| QuicheBuffer& operator=(QuicheBuffer&& other) { |
| buffer_ = std::move(other.buffer_); |
| size_ = other.size_; |
| |
| other.buffer_ = nullptr; |
| other.size_ = 0; |
| return *this; |
| } |
| |
| // Factory method to create a QuicheBuffer that holds a copy of `data`. |
| static QuicheBuffer Copy(QuicheBufferAllocator* allocator, |
| absl::string_view data) { |
| QuicheBuffer buffer(allocator, data.size()); |
| memcpy(buffer.data(), data.data(), data.size()); |
| return buffer; |
| } |
| |
| // Factory method to create a QuicheBuffer of length `buffer_length` that |
| // holds a copy of `buffer_length` bytes from `iov` starting at offset |
| // `iov_offset`. `iov` must be at least `iov_offset + buffer_length` total |
| // length. |
| static QuicheBuffer CopyFromIovec(QuicheBufferAllocator* allocator, |
| const struct iovec* iov, int iov_count, |
| size_t iov_offset, size_t buffer_length); |
| |
| const char* data() const { return buffer_.get(); } |
| char* data() { return buffer_.get(); } |
| size_t size() const { return size_; } |
| bool empty() const { return size_ == 0; } |
| absl::string_view AsStringView() const { |
| return absl::string_view(data(), size()); |
| } |
| |
| // Releases the ownership of the underlying buffer. |
| QuicheUniqueBufferPtr Release() { |
| size_ = 0; |
| return std::move(buffer_); |
| } |
| |
| private: |
| QuicheUniqueBufferPtr buffer_; |
| size_t size_; |
| }; |
| |
| } // namespace quiche |
| |
| #endif // QUICHE_COMMON_QUICHE_BUFFER_ALLOCATOR_H_ |