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/*
*
* 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.
*
*/
#include "src/core/lib/channel/subchannel_call_holder.h"
#include <grpc/support/alloc.h>
#include "src/core/lib/profiling/timers.h"
#define GET_CALL(holder) \
((grpc_subchannel_call *)(gpr_atm_acq_load(&(holder)->subchannel_call)))
#define CANCELLED_CALL ((grpc_subchannel_call *)1)
static void subchannel_ready(grpc_exec_ctx *exec_ctx, void *holder,
bool success);
static void retry_ops(grpc_exec_ctx *exec_ctx, void *retry_ops_args,
bool success);
static void add_waiting_locked(grpc_subchannel_call_holder *holder,
grpc_transport_stream_op *op);
static void fail_locked(grpc_exec_ctx *exec_ctx,
grpc_subchannel_call_holder *holder);
static void retry_waiting_locked(grpc_exec_ctx *exec_ctx,
grpc_subchannel_call_holder *holder);
void grpc_subchannel_call_holder_init(
grpc_subchannel_call_holder *holder,
grpc_subchannel_call_holder_pick_subchannel pick_subchannel,
void *pick_subchannel_arg, grpc_call_stack *owning_call) {
gpr_atm_rel_store(&holder->subchannel_call, 0);
holder->pick_subchannel = pick_subchannel;
holder->pick_subchannel_arg = pick_subchannel_arg;
gpr_mu_init(&holder->mu);
holder->connected_subchannel = NULL;
holder->waiting_ops = NULL;
holder->waiting_ops_count = 0;
holder->waiting_ops_capacity = 0;
holder->creation_phase = GRPC_SUBCHANNEL_CALL_HOLDER_NOT_CREATING;
holder->owning_call = owning_call;
}
void grpc_subchannel_call_holder_destroy(grpc_exec_ctx *exec_ctx,
grpc_subchannel_call_holder *holder) {
grpc_subchannel_call *call = GET_CALL(holder);
if (call != NULL && call != CANCELLED_CALL) {
GRPC_SUBCHANNEL_CALL_UNREF(exec_ctx, call, "holder");
}
GPR_ASSERT(holder->creation_phase ==
GRPC_SUBCHANNEL_CALL_HOLDER_NOT_CREATING);
gpr_mu_destroy(&holder->mu);
GPR_ASSERT(holder->waiting_ops_count == 0);
gpr_free(holder->waiting_ops);
}
void grpc_subchannel_call_holder_perform_op(grpc_exec_ctx *exec_ctx,
grpc_subchannel_call_holder *holder,
grpc_transport_stream_op *op) {
/* try to (atomically) get the call */
grpc_subchannel_call *call = GET_CALL(holder);
GPR_TIMER_BEGIN("grpc_subchannel_call_holder_perform_op", 0);
if (call == CANCELLED_CALL) {
grpc_transport_stream_op_finish_with_failure(exec_ctx, op);
GPR_TIMER_END("grpc_subchannel_call_holder_perform_op", 0);
return;
}
if (call != NULL) {
grpc_subchannel_call_process_op(exec_ctx, call, op);
GPR_TIMER_END("grpc_subchannel_call_holder_perform_op", 0);
return;
}
/* we failed; lock and figure out what to do */
gpr_mu_lock(&holder->mu);
retry:
/* need to recheck that another thread hasn't set the call */
call = GET_CALL(holder);
if (call == CANCELLED_CALL) {
gpr_mu_unlock(&holder->mu);
grpc_transport_stream_op_finish_with_failure(exec_ctx, op);
GPR_TIMER_END("grpc_subchannel_call_holder_perform_op", 0);
return;
}
if (call != NULL) {
gpr_mu_unlock(&holder->mu);
grpc_subchannel_call_process_op(exec_ctx, call, op);
GPR_TIMER_END("grpc_subchannel_call_holder_perform_op", 0);
return;
}
/* if this is a cancellation, then we can raise our cancelled flag */
if (op->cancel_with_status != GRPC_STATUS_OK) {
if (!gpr_atm_rel_cas(&holder->subchannel_call, 0, 1)) {
goto retry;
} else {
switch (holder->creation_phase) {
case GRPC_SUBCHANNEL_CALL_HOLDER_NOT_CREATING:
fail_locked(exec_ctx, holder);
break;
case GRPC_SUBCHANNEL_CALL_HOLDER_PICKING_SUBCHANNEL:
holder->pick_subchannel(exec_ctx, holder->pick_subchannel_arg, NULL,
&holder->connected_subchannel, NULL);
break;
}
gpr_mu_unlock(&holder->mu);
grpc_transport_stream_op_finish_with_failure(exec_ctx, op);
GPR_TIMER_END("grpc_subchannel_call_holder_perform_op", 0);
return;
}
}
/* if we don't have a subchannel, try to get one */
if (holder->creation_phase == GRPC_SUBCHANNEL_CALL_HOLDER_NOT_CREATING &&
holder->connected_subchannel == NULL &&
op->send_initial_metadata != NULL) {
holder->creation_phase = GRPC_SUBCHANNEL_CALL_HOLDER_PICKING_SUBCHANNEL;
grpc_closure_init(&holder->next_step, subchannel_ready, holder);
GRPC_CALL_STACK_REF(holder->owning_call, "pick_subchannel");
if (holder->pick_subchannel(
exec_ctx, holder->pick_subchannel_arg, op->send_initial_metadata,
&holder->connected_subchannel, &holder->next_step)) {
holder->creation_phase = GRPC_SUBCHANNEL_CALL_HOLDER_NOT_CREATING;
GRPC_CALL_STACK_UNREF(exec_ctx, holder->owning_call, "pick_subchannel");
}
}
/* if we've got a subchannel, then let's ask it to create a call */
if (holder->creation_phase == GRPC_SUBCHANNEL_CALL_HOLDER_NOT_CREATING &&
holder->connected_subchannel != NULL) {
gpr_atm_rel_store(
&holder->subchannel_call,
(gpr_atm)(uintptr_t)grpc_connected_subchannel_create_call(
exec_ctx, holder->connected_subchannel, holder->pollset));
retry_waiting_locked(exec_ctx, holder);
goto retry;
}
/* nothing to be done but wait */
add_waiting_locked(holder, op);
gpr_mu_unlock(&holder->mu);
GPR_TIMER_END("grpc_subchannel_call_holder_perform_op", 0);
}
static void subchannel_ready(grpc_exec_ctx *exec_ctx, void *arg, bool success) {
grpc_subchannel_call_holder *holder = arg;
gpr_mu_lock(&holder->mu);
GPR_ASSERT(holder->creation_phase ==
GRPC_SUBCHANNEL_CALL_HOLDER_PICKING_SUBCHANNEL);
holder->creation_phase = GRPC_SUBCHANNEL_CALL_HOLDER_NOT_CREATING;
if (holder->connected_subchannel == NULL) {
fail_locked(exec_ctx, holder);
} else if (1 == gpr_atm_acq_load(&holder->subchannel_call)) {
/* already cancelled before subchannel became ready */
fail_locked(exec_ctx, holder);
} else {
gpr_atm_rel_store(
&holder->subchannel_call,
(gpr_atm)(uintptr_t)grpc_connected_subchannel_create_call(
exec_ctx, holder->connected_subchannel, holder->pollset));
retry_waiting_locked(exec_ctx, holder);
}
gpr_mu_unlock(&holder->mu);
GRPC_CALL_STACK_UNREF(exec_ctx, holder->owning_call, "pick_subchannel");
}
typedef struct {
grpc_transport_stream_op *ops;
size_t nops;
grpc_subchannel_call *call;
} retry_ops_args;
static void retry_waiting_locked(grpc_exec_ctx *exec_ctx,
grpc_subchannel_call_holder *holder) {
retry_ops_args *a = gpr_malloc(sizeof(*a));
a->ops = holder->waiting_ops;
a->nops = holder->waiting_ops_count;
a->call = GET_CALL(holder);
if (a->call == CANCELLED_CALL) {
gpr_free(a);
fail_locked(exec_ctx, holder);
return;
}
holder->waiting_ops = NULL;
holder->waiting_ops_count = 0;
holder->waiting_ops_capacity = 0;
GRPC_SUBCHANNEL_CALL_REF(a->call, "retry_ops");
grpc_exec_ctx_enqueue(exec_ctx, grpc_closure_create(retry_ops, a), true,
NULL);
}
static void retry_ops(grpc_exec_ctx *exec_ctx, void *args, bool success) {
retry_ops_args *a = args;
size_t i;
for (i = 0; i < a->nops; i++) {
grpc_subchannel_call_process_op(exec_ctx, a->call, &a->ops[i]);
}
GRPC_SUBCHANNEL_CALL_UNREF(exec_ctx, a->call, "retry_ops");
gpr_free(a->ops);
gpr_free(a);
}
static void add_waiting_locked(grpc_subchannel_call_holder *holder,
grpc_transport_stream_op *op) {
GPR_TIMER_BEGIN("add_waiting_locked", 0);
if (holder->waiting_ops_count == holder->waiting_ops_capacity) {
holder->waiting_ops_capacity = GPR_MAX(3, 2 * holder->waiting_ops_capacity);
holder->waiting_ops =
gpr_realloc(holder->waiting_ops, holder->waiting_ops_capacity *
sizeof(*holder->waiting_ops));
}
holder->waiting_ops[holder->waiting_ops_count++] = *op;
GPR_TIMER_END("add_waiting_locked", 0);
}
static void fail_locked(grpc_exec_ctx *exec_ctx,
grpc_subchannel_call_holder *holder) {
size_t i;
for (i = 0; i < holder->waiting_ops_count; i++) {
grpc_transport_stream_op_finish_with_failure(exec_ctx,
&holder->waiting_ops[i]);
}
holder->waiting_ops_count = 0;
}
char *grpc_subchannel_call_holder_get_peer(
grpc_exec_ctx *exec_ctx, grpc_subchannel_call_holder *holder) {
grpc_subchannel_call *subchannel_call = GET_CALL(holder);
if (subchannel_call) {
return grpc_subchannel_call_get_peer(exec_ctx, subchannel_call);
} else {
return NULL;
}
}
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