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/*
*
* Copyright 2015, 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_INTERNAL_CORE_CHANNEL_SUBCHANNEL_CALL_HOLDER_H
#define GRPC_INTERNAL_CORE_CHANNEL_SUBCHANNEL_CALL_HOLDER_H
#include "src/core/client_config/subchannel.h"
/** Pick a subchannel for grpc_subchannel_call_holder;
Return 1 if subchannel is available immediately (in which case on_ready
should not be called), or 0 otherwise (in which case on_ready should be
called when the subchannel is available) */
typedef int (*grpc_subchannel_call_holder_pick_subchannel)(
grpc_exec_ctx *exec_ctx, void *arg, grpc_metadata_batch *initial_metadata,
grpc_subchannel **subchannel, grpc_closure *on_ready);
typedef enum {
GRPC_SUBCHANNEL_CALL_HOLDER_NOT_CREATING,
GRPC_SUBCHANNEL_CALL_HOLDER_PICKING_SUBCHANNEL,
GRPC_SUBCHANNEL_CALL_HOLDER_CREATING_CALL
} grpc_subchannel_call_holder_creation_phase;
/** Wrapper for holding a pointer to grpc_subchannel_call, and the
associated machinery to create such a pointer.
Handles queueing of stream ops until a call object is ready, waiting
for initial metadata before trying to create a call object,
and handling cancellation gracefully.
Both the channel and uchannel filter use this as their call_data. */
typedef struct grpc_subchannel_call_holder {
/** either 0 for no call, 1 for cancelled, or a pointer to a
grpc_subchannel_call */
gpr_atm subchannel_call;
/** Helper function to choose the subchannel on which to create
the call object. Channel filter delegates to the load
balancing policy (once it's ready); uchannel returns
immediately */
grpc_subchannel_call_holder_pick_subchannel pick_subchannel;
void *pick_subchannel_arg;
gpr_mu mu;
grpc_subchannel_call_holder_creation_phase creation_phase;
grpc_subchannel *subchannel;
grpc_pollset *pollset;
grpc_transport_stream_op *waiting_ops;
size_t waiting_ops_count;
size_t waiting_ops_capacity;
grpc_closure next_step;
} grpc_subchannel_call_holder;
void grpc_subchannel_call_holder_init(
grpc_subchannel_call_holder *holder,
grpc_subchannel_call_holder_pick_subchannel pick_subchannel,
void *pick_subchannel_arg);
void grpc_subchannel_call_holder_destroy(grpc_exec_ctx *exec_ctx,
grpc_subchannel_call_holder *holder);
void grpc_subchannel_call_holder_perform_op(grpc_exec_ctx *exec_ctx,
grpc_subchannel_call_holder *holder,
grpc_transport_stream_op *op);
char *grpc_subchannel_call_holder_get_peer(grpc_exec_ctx *exec_ctx,
grpc_subchannel_call_holder *holder,
grpc_channel *master);
#endif
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