| // Copyright 2017 The Fuchsia Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. |
| |
| // |
| // Provides an implementation of a simple thread-safe asynchronous |
| // dispatcher based on a Zircon completion port. The implementation |
| // is designed to avoid most dynamic memory allocation except for that |
| // which is required to create the loop in the first place or to manage |
| // the list of running threads. |
| // |
| // See README.md for example usage. |
| // |
| |
| #ifndef LIB_ASYNC_LOOP_LOOP_H_ |
| #define LIB_ASYNC_LOOP_LOOP_H_ |
| |
| #include <stdbool.h> |
| #include <stddef.h> |
| #include <threads.h> |
| |
| #include <zircon/compiler.h> |
| |
| #include <lib/async/dispatcher.h> |
| |
| __BEGIN_CDECLS |
| |
| // Pointer to a message loop created using |async_loop_create()|. |
| typedef struct async_loop async_loop_t; |
| |
| // Message loop configuration structure. |
| typedef void(async_loop_callback_t)(async_loop_t* loop, void* data); |
| typedef struct async_loop_config { |
| // If true, the loop will automatically register itself as the default |
| // dispatcher for the thread upon which it was created and will |
| // automatically unregister itself when destroyed (which must occur on |
| // the same thread). |
| // |
| // If false, the loop will not do this. The loop's creator is then |
| // responsible for retrieving the loop's dispatcher using |async_loop_get_dispatcher()| |
| // and passing it around explicitly or calling |async_set_default_dispatcher()| as needed. |
| // |
| // Note that the loop can be used even without setting it as the current |
| // thread's default. |
| bool make_default_for_current_thread; |
| |
| // A function to call before the dispatcher invokes each handler, or NULL if none. |
| async_loop_callback_t* prologue; |
| |
| // A function to call after the dispatcher invokes each handler, or NULL if none. |
| async_loop_callback_t* epilogue; |
| |
| // Data to pass to the callback functions. |
| void* data; |
| } async_loop_config_t; |
| |
| // Simple config that when passed to async_loop_create will create a loop |
| // that will automatically register itself as the default |
| // dispatcher for the thread upon which it was created and will |
| // automatically unregister itself when destroyed (which must occur on |
| // the same thread). |
| extern const async_loop_config_t kAsyncLoopConfigAttachToThread; |
| |
| // Simple config that when passed to async_loop_create will create a loop |
| // that is not registered to the current thread. |
| extern const async_loop_config_t kAsyncLoopConfigNoAttachToThread; |
| |
| // Creates a message loop and returns a pointer to it in |out_loop|. |
| // All operations on the message loop are thread-safe (except destroy). |
| // |
| // Note that it's ok to run the loop on a different thread from the one |
| // upon which it was created. |
| // |
| // |config| provides configuration for the message loop. Must not be null. |
| // |
| // Returns |ZX_OK| on success. |
| // Returns |ZX_ERR_NO_MEMORY| if allocation failed. |
| // May return other errors if the necessary internal handles could not be created. |
| // |
| // See also |kAsyncLoopConfigAttachToThread| and |kAsyncLoopConfigNoAttachToThread|. |
| zx_status_t async_loop_create(const async_loop_config_t* config, |
| async_loop_t** out_loop); |
| |
| // Gets the message loop's asynchronous dispatch interface. |
| async_dispatcher_t* async_loop_get_dispatcher(async_loop_t* loop); |
| |
| // Gets the message loop associated with the specified asynchronous dispatch interface |
| // |
| // This function assumes the dispatcher is backed by an |async_loop_t| which was created |
| // using |async_loop_create()|. Its behavior is undefined if used with other dispatcher |
| // implementations. |
| async_loop_t* async_loop_from_dispatcher(async_dispatcher_t* dispatcher); |
| |
| // Shuts down the message loop, notifies handlers which asked to handle shutdown. |
| // The message loop must not currently be running on any threads other than |
| // those started by |async_loop_start_thread()| which this function will join. |
| // |
| // Does nothing if already shutting down. |
| void async_loop_shutdown(async_loop_t* loop); |
| |
| // Destroys the message loop. |
| // Implicitly calls |async_loop_shutdown()| and joins all threads started |
| // using |async_loop_start_thread()| before destroying the loop itself. |
| void async_loop_destroy(async_loop_t* loop); |
| |
| // Runs the message loop on the current thread. |
| // This function can be called on multiple threads to setup a multi-threaded |
| // dispatcher. |
| // |
| // Dispatches events until the |deadline| expires or the loop is quitted. |
| // Use |ZX_TIME_INFINITE| to dispatch events indefinitely. |
| // |
| // If |once| is true, performs a single unit of work then returns. |
| // |
| // Returns |ZX_OK| if the dispatcher returns after one cycle. |
| // Returns |ZX_ERR_TIMED_OUT| if the deadline expired. |
| // Returns |ZX_ERR_CANCELED| if the loop quitted. |
| // Returns |ZX_ERR_BAD_STATE| if the loop was shut down with |async_loop_shutdown()|. |
| zx_status_t async_loop_run(async_loop_t* loop, zx_time_t deadline, bool once); |
| |
| // Dispatches events until there are none remaining, and then returns without |
| // waiting. This is useful for unit testing, because the behavior doesn't depend |
| // on time. |
| // |
| // Returns |ZX_OK| if the dispatcher reaches an idle state. |
| // Returns |ZX_ERR_CANCELED| if the loop quitted. |
| // Returns |ZX_ERR_BAD_STATE| if the loop was shut down with |async_loop_shutdown()|. |
| zx_status_t async_loop_run_until_idle(async_loop_t* loop); |
| |
| // Quits the message loop. |
| // Active invocations of |async_loop_run()| and threads started using |
| // |async_loop_start_thread()| will eventually terminate upon completion of their |
| // current unit of work. |
| // |
| // Subsequent calls to |async_loop_run()| or |async_loop_start_thread()| |
| // will return immediately until |async_loop_reset_quit()| is called. |
| void async_loop_quit(async_loop_t* loop); |
| |
| // Resets the quit state of the message loop so that it can be restarted |
| // using |async_loop_run()| or |async_loop_start_thread()|. |
| // |
| // This function must only be called when the message loop is not running. |
| // The caller must ensure all active invocations of |async_loop_run()| and |
| // threads started using |async_loop_start_thread()| have terminated before |
| // resetting the quit state. |
| // |
| // Returns |ZX_OK| if the loop's state was |ASYNC_LOOP_RUNNABLE| or |ASYNC_LOOP_QUIT|. |
| // Returns |ZX_ERR_BAD_STATE| if the loop's state was |ASYNC_LOOP_SHUTDOWN| or if |
| // the message loop is currently active on one or more threads. |
| zx_status_t async_loop_reset_quit(async_loop_t* loop); |
| |
| // Returns the current state of the message loop. |
| typedef uint32_t async_loop_state_t; |
| #define ASYNC_LOOP_RUNNABLE ((async_loop_state_t) 0) |
| #define ASYNC_LOOP_QUIT ((async_loop_state_t) 1) |
| #define ASYNC_LOOP_SHUTDOWN ((async_loop_state_t) 2) |
| async_loop_state_t async_loop_get_state(async_loop_t* loop); |
| |
| // Starts a message loop running on a new thread. |
| // The thread will run until the loop quits. |
| // |
| // |name| is the desired name for the new thread, may be NULL. |
| // If |out_thread| is not NULL, it is set to the new thread identifier. |
| // |
| // Returns |ZX_OK| on success. |
| // Returns |ZX_ERR_BAD_STATE| if the loop was shut down with |async_loop_shutdown()|. |
| // Returns |ZX_ERR_NO_MEMORY| if allocation or thread creation failed. |
| zx_status_t async_loop_start_thread(async_loop_t* loop, const char* name, |
| thrd_t* out_thread); |
| |
| // Blocks until all dispatch threads started with |async_loop_start_thread()| |
| // have terminated. |
| void async_loop_join_threads(async_loop_t* loop); |
| |
| __END_CDECLS |
| |
| #endif // LIB_ASYNC_LOOP_LOOP_H_ |