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/*
*
* 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/slice_buffer.h>
#include "src/core/lib/iomgr/exec_ctx.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)
#ifdef __cplusplus
extern "C" {
#endif
typedef struct grpc_byte_stream grpc_byte_stream;
typedef struct {
bool (*next)(grpc_exec_ctx *exec_ctx, grpc_byte_stream *byte_stream,
size_t max_size_hint, grpc_closure *on_complete);
grpc_error *(*pull)(grpc_exec_ctx *exec_ctx, grpc_byte_stream *byte_stream,
grpc_slice *slice);
void (*shutdown)(grpc_exec_ctx *exec_ctx, grpc_byte_stream *byte_stream,
grpc_error *error);
void (*destroy)(grpc_exec_ctx *exec_ctx, grpc_byte_stream *byte_stream);
} grpc_byte_stream_vtable;
struct grpc_byte_stream {
uint32_t length;
uint32_t flags;
const grpc_byte_stream_vtable *vtable;
};
// Returns true if the bytes are available immediately (in which case
// on_complete will not be called), false if the bytes will be available
// asynchronously.
//
// max_size_hint can be set as a hint as to the maximum number
// of bytes that would be acceptable to read.
bool grpc_byte_stream_next(grpc_exec_ctx *exec_ctx,
grpc_byte_stream *byte_stream, size_t max_size_hint,
grpc_closure *on_complete);
// Returns the next slice in the byte stream when it is ready (indicated by
// either grpc_byte_stream_next returning true or on_complete passed to
// grpc_byte_stream_next is called).
//
// Once a slice is returned into *slice, it is owned by the caller.
grpc_error *grpc_byte_stream_pull(grpc_exec_ctx *exec_ctx,
grpc_byte_stream *byte_stream,
grpc_slice *slice);
// Shuts down the byte stream.
//
// If there is a pending call to on_complete from grpc_byte_stream_next(),
// it will be invoked with the error passed to grpc_byte_stream_shutdown().
//
// The next call to grpc_byte_stream_pull() (if any) will return the error
// passed to grpc_byte_stream_shutdown().
void grpc_byte_stream_shutdown(grpc_exec_ctx *exec_ctx,
grpc_byte_stream *byte_stream,
grpc_error *error);
void grpc_byte_stream_destroy(grpc_exec_ctx *exec_ctx,
grpc_byte_stream *byte_stream);
// grpc_slice_buffer_stream
//
// A grpc_byte_stream that wraps a slice buffer. The stream takes
// ownership of the slices in the buffer, and on destruction will
// reset the contents of the buffer.
typedef struct grpc_slice_buffer_stream {
grpc_byte_stream base;
grpc_slice_buffer *backing_buffer;
size_t cursor;
grpc_error *shutdown_error;
} grpc_slice_buffer_stream;
void grpc_slice_buffer_stream_init(grpc_slice_buffer_stream *stream,
grpc_slice_buffer *slice_buffer,
uint32_t flags);
// grpc_caching_byte_stream
//
// A grpc_byte_stream 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
// grpc_caching_byte_streams simultaneously drawing from the same underlying
// grpc_byte_stream_cache at the same time.
typedef struct {
grpc_byte_stream *underlying_stream;
grpc_slice_buffer cache_buffer;
} grpc_byte_stream_cache;
// Takes ownership of underlying_stream.
void grpc_byte_stream_cache_init(grpc_byte_stream_cache *cache,
grpc_byte_stream *underlying_stream);
// Must not be called while still in use by a grpc_caching_byte_stream.
void grpc_byte_stream_cache_destroy(grpc_exec_ctx *exec_ctx,
grpc_byte_stream_cache *cache);
typedef struct {
grpc_byte_stream base;
grpc_byte_stream_cache *cache;
size_t cursor;
grpc_error *shutdown_error;
} grpc_caching_byte_stream;
void grpc_caching_byte_stream_init(grpc_caching_byte_stream *stream,
grpc_byte_stream_cache *cache);
// Resets the byte stream to the start of the underlying stream.
void grpc_caching_byte_stream_reset(grpc_caching_byte_stream *stream);
#ifdef __cplusplus
}
#endif
#endif /* GRPC_CORE_LIB_TRANSPORT_BYTE_STREAM_H */
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