Initial checkin of gRPC to third_party/

third_party/grpc/src/core/iomgr/exec_ctx.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_INTERNAL_CORE_IOMGR_EXEC_CTX_H
+#define GRPC_INTERNAL_CORE_IOMGR_EXEC_CTX_H
+
+#include "src/core/iomgr/closure.h"
+
+/** Execution context.
+ *  A bag of data that collects information along a callstack.
+ *  Generally created at public API entry points, and passed down as
+ *  pointer to child functions that manipulate it.
+ *
+ *  Specific responsibilities (this may grow in the future):
+ *  - track a list of work that needs to be delayed until the top of the
+ *    call stack (this provides a convenient mechanism to run callbacks
+ *    without worrying about locking issues)
+ *
+ *  CONVENTIONS:
+ *  Instance of this must ALWAYS be constructed on the stack, never
+ *  heap allocated. Instances and pointers to them must always be called
+ *  exec_ctx. Instances are always passed as the first argument
+ *  to a function that takes it, and always as a pointer (grpc_exec_ctx
+ *  is never copied).
+ */
+struct grpc_exec_ctx {
+  grpc_closure_list closure_list;
+};
+
+/** A workqueue represents a list of work to be executed asynchronously.
+    Forward declared here to avoid a circular dependency with workqueue.h. */
+struct grpc_workqueue;
+typedef struct grpc_workqueue grpc_workqueue;
+
+#define GRPC_EXEC_CTX_INIT \
+  { GRPC_CLOSURE_LIST_INIT }
+
+/** Flush any work that has been enqueued onto this grpc_exec_ctx.
+ *  Caller must guarantee that no interfering locks are held.
+ *  Returns true if work was performed, false otherwise. */
+bool grpc_exec_ctx_flush(grpc_exec_ctx *exec_ctx);
+/** Finish any pending work for a grpc_exec_ctx. Must be called before
+ *  the instance is destroyed, or work may be lost. */
+void grpc_exec_ctx_finish(grpc_exec_ctx *exec_ctx);
+/** Add a closure to be executed at the next flush/finish point */
+void grpc_exec_ctx_enqueue(grpc_exec_ctx *exec_ctx, grpc_closure *closure,
+                           bool success,
+                           grpc_workqueue *offload_target_or_null);
+/** Add a list of closures to be executed at the next flush/finish point.
+ *  Leaves \a list empty. */
+void grpc_exec_ctx_enqueue_list(grpc_exec_ctx *exec_ctx,
+                                grpc_closure_list *list,
+                                grpc_workqueue *offload_target_or_null);
+
+#endif