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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.
*
*/
#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_closure *c = g_executor.closures.head;
grpc_closure_list_init(&g_executor.closures);
gpr_mu_unlock(&g_executor.mu);
while (c != NULL) {
grpc_closure *next = c->next_data.next;
grpc_error *error = c->error_data.error;
#ifndef NDEBUG
c->scheduled = false;
#endif
c->cb(&exec_ctx, c->cb_arg, error);
GRPC_ERROR_UNREF(error);
c = next;
}
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_ASSERT(gpr_thd_new(&g_executor.tid, closure_exec_thread_func, NULL,
&g_executor.options));
g_executor.pending_join = 1;
}
static void executor_push(grpc_exec_ctx *exec_ctx, grpc_closure *closure,
grpc_error *error) {
gpr_mu_lock(&g_executor.mu);
if (g_executor.shutting_down == 0) {
grpc_closure_list_append(&g_executor.closures, closure, error);
maybe_spawn_locked();
}
gpr_mu_unlock(&g_executor.mu);
}
void grpc_executor_shutdown(grpc_exec_ctx *exec_ctx) {
int pending_join;
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_closure *c = g_executor.closures.head;
grpc_closure_list_init(&g_executor.closures);
while (c != NULL) {
grpc_closure *next = c->next_data.next;
grpc_error *error = c->error_data.error;
#ifndef NDEBUG
c->scheduled = false;
#endif
c->cb(exec_ctx, c->cb_arg, error);
GRPC_ERROR_UNREF(error);
c = next;
}
grpc_exec_ctx_flush(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);
}
static const grpc_closure_scheduler_vtable executor_vtable = {
executor_push, executor_push, "executor"};
static grpc_closure_scheduler executor_scheduler = {&executor_vtable};
grpc_closure_scheduler *grpc_executor_scheduler = &executor_scheduler;
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