src/core/lib/transport/byte_stream.h

/*
 *
 * Copyright 2015-2016, Google Inc.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are
 * met:
 *
 *     * Redistributions of source code must retain the above copyright
 * notice, this list of conditions and the following disclaimer.
 *     * Redistributions in binary form must reproduce the above
 * copyright notice, this list of conditions and the following disclaimer
 * in the documentation and/or other materials provided with the
 * distribution.
 *     * Neither the name of Google Inc. nor the names of its
 * contributors may be used to endorse or promote products derived from
 * this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 */

#ifndef GRPC_CORE_LIB_TRANSPORT_BYTE_STREAM_H
#define GRPC_CORE_LIB_TRANSPORT_BYTE_STREAM_H

#include <grpc/support/slice_buffer.h>
#include "src/core/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)

struct grpc_byte_stream;
typedef struct grpc_byte_stream grpc_byte_stream;

struct grpc_byte_stream {
  uint32_t length;
  uint32_t flags;
  int (*next)(grpc_exec_ctx *exec_ctx, grpc_byte_stream *byte_stream,
              gpr_slice *slice, size_t max_size_hint,
              grpc_closure *on_complete);
  void (*destroy)(grpc_exec_ctx *exec_ctx, grpc_byte_stream *byte_stream);
};

/* returns 1 if the bytes are available immediately (in which case
 * on_complete will not be called), 0 if the bytes will be available
 * asynchronously.
 *
 * on entry, *remaining can be set as a hint as to the maximum number
 * of bytes that would be acceptable to read.
 *
 * fills *buffer, *length, *remaining with the bytes, length of bytes
 * and length of data remaining to be read before either returning 1
 * or calling on_complete.
 *
 * once a slice is returned into *slice, it is owned by the caller.
 */
int grpc_byte_stream_next(grpc_exec_ctx *exec_ctx,
                          grpc_byte_stream *byte_stream, gpr_slice *slice,
                          size_t max_size_hint, grpc_closure *on_complete);

void grpc_byte_stream_destroy(grpc_exec_ctx *exec_ctx,
                              grpc_byte_stream *byte_stream);

/* grpc_byte_stream that wraps a slice buffer */
typedef struct grpc_slice_buffer_stream {
  grpc_byte_stream base;
  gpr_slice_buffer *backing_buffer;
  size_t cursor;
} grpc_slice_buffer_stream;

void grpc_slice_buffer_stream_init(grpc_slice_buffer_stream *stream,
                                   gpr_slice_buffer *slice_buffer,
                                   uint32_t flags);

#endif /* GRPC_CORE_LIB_TRANSPORT_BYTE_STREAM_H */