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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.
*
*/
#include "src/core/lib/iomgr/executor.h"
#include <string.h>
#include <grpc/support/alloc.h>
#include <grpc/support/log.h>
#include <grpc/support/sync.h>
#include <grpc/support/thd.h>
#include "src/core/lib/iomgr/exec_ctx.h"
typedef struct grpc_executor_data {
int busy; /**< is the thread currently running? */
int shutting_down; /**< has \a grpc_shutdown() been invoked? */
int pending_join; /**< has the thread finished but not been joined? */
grpc_closure_list closures; /**< collection of pending work */
gpr_thd_id tid; /**< thread id of the thread, only valid if \a busy or \a
pending_join are true */
gpr_thd_options options;
gpr_mu mu;
} grpc_executor;
static grpc_executor g_executor;
void grpc_executor_init() {
memset(&g_executor, 0, sizeof(grpc_executor));
gpr_mu_init(&g_executor.mu);
g_executor.options = gpr_thd_options_default();
gpr_thd_options_set_joinable(&g_executor.options);
}
/* thread body */
static void closure_exec_thread_func(void *ignored) {
grpc_exec_ctx exec_ctx = GRPC_EXEC_CTX_INIT;
while (1) {
gpr_mu_lock(&g_executor.mu);
if (g_executor.shutting_down != 0) {
gpr_mu_unlock(&g_executor.mu);
break;
}
if (grpc_closure_list_empty(g_executor.closures)) {
/* no more work, time to die */
GPR_ASSERT(g_executor.busy == 1);
g_executor.busy = 0;
gpr_mu_unlock(&g_executor.mu);
break;
} else {
grpc_exec_ctx_enqueue_list(&exec_ctx, &g_executor.closures, NULL);
}
gpr_mu_unlock(&g_executor.mu);
grpc_exec_ctx_flush(&exec_ctx);
}
grpc_exec_ctx_finish(&exec_ctx);
}
/* Spawn the thread if new work has arrived a no thread is up */
static void maybe_spawn_locked() {
if (grpc_closure_list_empty(g_executor.closures) == 1) {
return;
}
if (g_executor.shutting_down == 1) {
return;
}
if (g_executor.busy != 0) {
/* Thread still working. New work will be picked up by already running
* thread. Not spawning anything. */
return;
} else if (g_executor.pending_join != 0) {
/* Pickup the remains of the previous incarnations of the thread. */
gpr_thd_join(g_executor.tid);
g_executor.pending_join = 0;
}
/* All previous instances of the thread should have been joined at this point.
* Spawn time! */
g_executor.busy = 1;
gpr_thd_new(&g_executor.tid, closure_exec_thread_func, NULL,
&g_executor.options);
g_executor.pending_join = 1;
}
void grpc_executor_enqueue(grpc_closure *closure, bool success) {
gpr_mu_lock(&g_executor.mu);
if (g_executor.shutting_down == 0) {
grpc_closure_list_add(&g_executor.closures, closure, success);
maybe_spawn_locked();
}
gpr_mu_unlock(&g_executor.mu);
}
void grpc_executor_shutdown() {
int pending_join;
grpc_exec_ctx exec_ctx = GRPC_EXEC_CTX_INIT;
gpr_mu_lock(&g_executor.mu);
pending_join = g_executor.pending_join;
g_executor.shutting_down = 1;
gpr_mu_unlock(&g_executor.mu);
/* we can release the lock at this point despite the access to the closure
* list below because we aren't accepting new work */
/* Execute pending callbacks, some may be performing cleanups */
grpc_exec_ctx_enqueue_list(&exec_ctx, &g_executor.closures, NULL);
grpc_exec_ctx_finish(&exec_ctx);
GPR_ASSERT(grpc_closure_list_empty(g_executor.closures));
if (pending_join) {
gpr_thd_join(g_executor.tid);
}
gpr_mu_destroy(&g_executor.mu);
}
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