| /* |
| * |
| * Copyright 2015 gRPC 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 |
| * |
| * http://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. |
| * |
| */ |
| |
| #ifndef GRPC_CORE_LIB_TRANSPORT_BYTE_STREAM_H |
| #define GRPC_CORE_LIB_TRANSPORT_BYTE_STREAM_H |
| |
| #include <grpc/support/port_platform.h> |
| |
| #include <grpc/slice_buffer.h> |
| #include "src/core/lib/gprpp/abstract.h" |
| #include "src/core/lib/gprpp/orphanable.h" |
| #include "src/core/lib/iomgr/closure.h" |
| |
| /** Internal bit flag for grpc_begin_message's \a flags signaling the use of |
| * compression for the message */ |
| #define GRPC_WRITE_INTERNAL_COMPRESS (0x80000000u) |
| /** Mask of all valid internal flags. */ |
| #define GRPC_WRITE_INTERNAL_USED_MASK (GRPC_WRITE_INTERNAL_COMPRESS) |
| |
| namespace grpc_core { |
| |
| class ByteStream : public Orphanable { |
| public: |
| virtual ~ByteStream() {} |
| |
| // Returns true if the bytes are available immediately (in which case |
| // on_complete will not be called), or false if the bytes will be available |
| // asynchronously (in which case on_complete will be called when they |
| // are available). |
| // |
| // max_size_hint can be set as a hint as to the maximum number |
| // of bytes that would be acceptable to read. |
| virtual bool Next(size_t max_size_hint, |
| grpc_closure* on_complete) GRPC_ABSTRACT; |
| |
| // Returns the next slice in the byte stream when it is available, as |
| // indicated by Next(). |
| // |
| // Once a slice is returned into *slice, it is owned by the caller. |
| virtual grpc_error* Pull(grpc_slice* slice) GRPC_ABSTRACT; |
| |
| // Shuts down the byte stream. |
| // |
| // If there is a pending call to on_complete from Next(), it will be |
| // invoked with the error passed to Shutdown(). |
| // |
| // The next call to Pull() (if any) will return the error passed to |
| // Shutdown(). |
| virtual void Shutdown(grpc_error* error) GRPC_ABSTRACT; |
| |
| uint32_t length() const { return length_; } |
| uint32_t flags() const { return flags_; } |
| |
| void set_flags(uint32_t flags) { flags_ = flags; } |
| |
| GRPC_ABSTRACT_BASE_CLASS |
| |
| protected: |
| ByteStream(uint32_t length, uint32_t flags) |
| : length_(length), flags_(flags) {} |
| |
| private: |
| const uint32_t length_; |
| uint32_t flags_; |
| }; |
| |
| // |
| // SliceBufferByteStream |
| // |
| // A ByteStream that wraps a slice buffer. |
| // |
| |
| class SliceBufferByteStream : public ByteStream { |
| public: |
| // Removes all slices in slice_buffer, leaving it empty. |
| SliceBufferByteStream(grpc_slice_buffer* slice_buffer, uint32_t flags); |
| |
| ~SliceBufferByteStream(); |
| |
| void Orphan() override; |
| |
| bool Next(size_t max_size_hint, grpc_closure* on_complete) override; |
| grpc_error* Pull(grpc_slice* slice) override; |
| void Shutdown(grpc_error* error) override; |
| |
| private: |
| grpc_slice_buffer backing_buffer_; |
| size_t cursor_ = 0; |
| grpc_error* shutdown_error_ = GRPC_ERROR_NONE; |
| }; |
| |
| // |
| // CachingByteStream |
| // |
| // A ByteStream that that wraps an underlying byte stream but caches |
| // the resulting slices in a slice buffer. If an initial attempt fails |
| // without fully draining the underlying stream, a new caching stream |
| // can be created from the same underlying cache, in which case it will |
| // return whatever is in the backing buffer before continuing to read the |
| // underlying stream. |
| // |
| // NOTE: No synchronization is done, so it is not safe to have multiple |
| // CachingByteStreams simultaneously drawing from the same underlying |
| // ByteStreamCache at the same time. |
| // |
| |
| class ByteStreamCache { |
| public: |
| class CachingByteStream : public ByteStream { |
| public: |
| explicit CachingByteStream(ByteStreamCache* cache); |
| |
| ~CachingByteStream(); |
| |
| void Orphan() override; |
| |
| bool Next(size_t max_size_hint, grpc_closure* on_complete) override; |
| grpc_error* Pull(grpc_slice* slice) override; |
| void Shutdown(grpc_error* error) override; |
| |
| // Resets the byte stream to the start of the underlying stream. |
| void Reset(); |
| |
| private: |
| ByteStreamCache* cache_; |
| size_t cursor_ = 0; |
| size_t offset_ = 0; |
| grpc_error* shutdown_error_ = GRPC_ERROR_NONE; |
| }; |
| |
| explicit ByteStreamCache(OrphanablePtr<ByteStream> underlying_stream); |
| |
| ~ByteStreamCache(); |
| |
| // Must not be destroyed while still in use by a CachingByteStream. |
| void Destroy(); |
| |
| grpc_slice_buffer* cache_buffer() { return &cache_buffer_; } |
| |
| private: |
| OrphanablePtr<ByteStream> underlying_stream_; |
| uint32_t length_; |
| uint32_t flags_; |
| grpc_slice_buffer cache_buffer_; |
| }; |
| |
| } // namespace grpc_core |
| |
| #endif /* GRPC_CORE_LIB_TRANSPORT_BYTE_STREAM_H */ |