| #ifndef QUICHE_SPDY_CORE_SPDY_HEADER_STORAGE_H_ |
| #define QUICHE_SPDY_CORE_SPDY_HEADER_STORAGE_H_ |
| |
| #include "absl/strings/string_view.h" |
| #include "net/third_party/quiche/src/common/platform/api/quiche_export.h" |
| #include "net/third_party/quiche/src/spdy/core/spdy_simple_arena.h" |
| |
| namespace spdy { |
| |
| // This class provides a backing store for absl::string_views. It previously |
| // used custom allocation logic, but now uses an UnsafeArena instead. It has the |
| // property that absl::string_views that refer to data in SpdyHeaderStorage are |
| // never invalidated until the SpdyHeaderStorage is deleted or Clear() is |
| // called. |
| // |
| // Write operations always append to the last block. If there is not enough |
| // space to perform the write, a new block is allocated, and any unused space |
| // is wasted. |
| class QUICHE_EXPORT_PRIVATE SpdyHeaderStorage { |
| public: |
| SpdyHeaderStorage(); |
| |
| SpdyHeaderStorage(const SpdyHeaderStorage&) = delete; |
| SpdyHeaderStorage& operator=(const SpdyHeaderStorage&) = delete; |
| |
| SpdyHeaderStorage(SpdyHeaderStorage&& other) = default; |
| SpdyHeaderStorage& operator=(SpdyHeaderStorage&& other) = default; |
| |
| absl::string_view Write(absl::string_view s); |
| |
| // If |s| points to the most recent allocation from arena_, the arena will |
| // reclaim the memory. Otherwise, this method is a no-op. |
| void Rewind(absl::string_view s); |
| |
| void Clear() { arena_.Reset(); } |
| |
| // Given a list of fragments and a separator, writes the fragments joined by |
| // the separator to a contiguous region of memory. Returns a absl::string_view |
| // pointing to the region of memory. |
| absl::string_view WriteFragments( |
| const std::vector<absl::string_view>& fragments, |
| absl::string_view separator); |
| |
| size_t bytes_allocated() const { return arena_.status().bytes_allocated(); } |
| |
| size_t EstimateMemoryUsage() const { return bytes_allocated(); } |
| |
| private: |
| SpdySimpleArena arena_; |
| }; |
| |
| // Writes |fragments| to |dst|, joined by |separator|. |dst| must be large |
| // enough to hold the result. Returns the number of bytes written. |
| QUICHE_EXPORT_PRIVATE size_t |
| Join(char* dst, |
| const std::vector<absl::string_view>& fragments, |
| absl::string_view separator); |
| |
| } // namespace spdy |
| |
| #endif // QUICHE_SPDY_CORE_SPDY_HEADER_STORAGE_H_ |