From f44ba092651aa75055e109e04b4164ea92ae7fdc Mon Sep 17 00:00:00 2001 From: Lennart Poettering Date: Mon, 19 Jun 2006 21:53:48 +0000 Subject: big s/polyp/pulse/g git-svn-id: file:///home/lennart/svn/public/pulseaudio/trunk@1033 fefdeb5f-60dc-0310-8127-8f9354f1896f --- src/pulse/context.h | 230 ++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 230 insertions(+) create mode 100644 src/pulse/context.h (limited to 'src/pulse/context.h') diff --git a/src/pulse/context.h b/src/pulse/context.h new file mode 100644 index 00000000..65d70e8b --- /dev/null +++ b/src/pulse/context.h @@ -0,0 +1,230 @@ +#ifndef foocontexthfoo +#define foocontexthfoo + +/* $Id$ */ + +/*** + This file is part of PulseAudio. + + PulseAudio is free software; you can redistribute it and/or modify + it under the terms of the GNU Lesser General Public License as published + by the Free Software Foundation; either version 2 of the License, + or (at your option) any later version. + + PulseAudio is distributed in the hope that it will be useful, but + WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + General Public License for more details. + + You should have received a copy of the GNU Lesser General Public License + along with PulseAudio; if not, write to the Free Software + Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 + USA. +***/ + +#include +#include +#include +#include +#include + +/** \page async Asynchronous API + * + * \section overv_sec Overview + * + * The asynchronous API is the native interface to the pulseaudio library. + * It allows full access to all available functions. This also means that + * it is rather complex and can take some time to fully master. + * + * \section mainloop_sec Main Loop Abstraction + * + * The API is based around an asynchronous event loop, or main loop, + * abstraction. This abstraction contains three basic elements: + * + * \li Deferred events - Events that will trigger as soon as possible. Note + * that some implementations may block all other events + * when a deferred event is active. + * \li I/O events - Events that trigger on file descriptor activities. + * \li Times events - Events that trigger after a fixed ammount of time. + * + * The abstraction is represented as a number of function pointers in the + * pa_mainloop_api structure. + * + * To actually be able to use these functions, an implementation needs to + * be coupled to the abstraction. There are three of these shipped with + * pulseaudio, but any other can be used with a minimal ammount of work, + * provided it supports the three basic events listed above. + * + * The implementations shipped with pulseaudio are: + * + * \li \subpage mainloop - A minimal but fast implementation based on poll(). + * \li \subpage threaded_mainloop - A special version of the previous + * implementation where all of Polypaudio's + * internal handling runs in a separate + * thread. + * \li \subpage glib-mainloop - A wrapper around GLIB's main loop. Available + * for both GLIB 1.2 and GLIB 2.x. + * + * UNIX signals may be hooked to a main loop using the functions from + * \ref mainloop-signal.h. These rely only on the main loop abstraction + * and can therefore be used with any of the implementations. + * + * \section refcnt_sec Reference Counting + * + * Almost all objects in pulseaudio are reference counted. What that means + * is that you rarely malloc() or free() any objects. Instead you increase + * and decrease their reference counts. Whenever an object's reference + * count reaches zero, that object gets destroy and any resources it uses + * get freed. + * + * The benefit of this design is that an application need not worry about + * whether or not it needs to keep an object around in case the library is + * using it internally. If it is, then it has made sure it has its own + * reference to it. + * + * Whenever the library creates an object, it will have an initial + * reference count of one. Most of the time, this single reference will be + * sufficient for the application, so all required reference count + * interaction will be a single call to the objects unref function. + * + * \section context_sec Context + * + * A context is the basic object for a connection to a pulseaudio server. + * It multiplexes commands, data streams and events through a single + * channel. + * + * There is no need for more than one context per application, unless + * connections to multiple servers are needed. + * + * \subsection ops_subsec Operations + * + * All operations on the context are performed asynchronously. I.e. the + * client will not wait for the server to complete the request. To keep + * track of all these in-flight operations, the application is given a + * pa_operation object for each asynchronous operation. + * + * There are only two actions (besides reference counting) that can be + * performed on a pa_operation: querying its state with + * pa_operation_get_state() and aborting it with pa_operation_cancel(). + * + * A pa_operation object is reference counted, so an application must + * make sure to unreference it, even if it has no intention of using it. + * + * \subsection conn_subsec Connecting + * + * A context must be connected to a server before any operation can be + * issued. Calling pa_context_connect() will initiate the connection + * procedure. Unlike most asynchronous operations, connecting does not + * result in a pa_operation object. Instead, the application should + * register a callback using pa_context_set_state_callback(). + * + * \subsection disc_subsec Disconnecting + * + * When the sound support is no longer needed, the connection needs to be + * closed using pa_context_disconnect(). This is an immediate function that + * works synchronously. + * + * Since the context object has references to other objects it must be + * disconnected after use or there is a high risk of memory leaks. If the + * connection has terminated by itself, then there is no need to explicitly + * disconnect the context using pa_context_disconnect(). + * + * \section Functions + * + * The sound server's functionality can be divided into a number of + * subsections: + * + * \li \subpage streams + * \li \subpage scache + * \li \subpage introspect + * \li \subpage subscribe + */ + +/** \file + * Connection contexts for asynchrononous communication with a + * server. A pa_context object wraps a connection to a pulseaudio + * server using its native protocol. */ + +/** \example pacat.c + * A playback and recording tool using the asynchronous API */ + +/** \example paplay.c + * A sound file playback tool using the asynchronous API, based on libsndfile */ + +PA_C_DECL_BEGIN + +/** An opaque connection context to a daemon */ +typedef struct pa_context pa_context; + +/** Generic notification callback prototype */ +typedef void (*pa_context_notify_cb_t)(pa_context *c, void *userdata); + +/** A generic callback for operation completion */ +typedef void (*pa_context_success_cb_t) (pa_context *c, int success, void *userdata); + +/** Instantiate a new connection context with an abstract mainloop API + * and an application name */ +pa_context *pa_context_new(pa_mainloop_api *mainloop, const char *name); + +/** Decrease the reference counter of the context by one */ +void pa_context_unref(pa_context *c); + +/** Increase the reference counter of the context by one */ +pa_context* pa_context_ref(pa_context *c); + +/** Set a callback function that is called whenever the context status changes */ +void pa_context_set_state_callback(pa_context *c, pa_context_notify_cb_t cb, void *userdata); + +/** Return the error number of the last failed operation */ +int pa_context_errno(pa_context *c); + +/** Return non-zero if some data is pending to be written to the connection */ +int pa_context_is_pending(pa_context *c); + +/** Return the current context status */ +pa_context_state_t pa_context_get_state(pa_context *c); + +/** Connect the context to the specified server. If server is NULL, +connect to the default server. This routine may but will not always +return synchronously on error. Use pa_context_set_state_callback() to +be notified when the connection is established. If flags doesn't have +PA_NOAUTOSPAWN set and no specific server is specified or accessible a +new daemon is spawned. If api is non-NULL, the functions specified in +the structure are used when forking a new child process. */ +int pa_context_connect(pa_context *c, const char *server, pa_context_flags_t flags, const pa_spawn_api *api); + +/** Terminate the context connection immediately */ +void pa_context_disconnect(pa_context *c); + +/** Drain the context. If there is nothing to drain, the function returns NULL */ +pa_operation* pa_context_drain(pa_context *c, pa_context_notify_cb_t cb, void *userdata); + +/** Tell the daemon to exit. The returned operation is unlikely to + * complete succesfully, since the daemon probably died before + * returning a success notification */ +pa_operation* pa_context_exit_daemon(pa_context *c, pa_context_success_cb_t cb, void *userdata); + +/** Set the name of the default sink. \since 0.4 */ +pa_operation* pa_context_set_default_sink(pa_context *c, const char *name, pa_context_success_cb_t cb, void *userdata); + +/** Set the name of the default source. \since 0.4 */ +pa_operation* pa_context_set_default_source(pa_context *c, const char *name, pa_context_success_cb_t cb, void *userdata); + +/** Returns 1 when the connection is to a local daemon. Returns negative when no connection has been made yet. \since 0.5 */ +int pa_context_is_local(pa_context *c); + +/** Set a different application name for context on the server. \since 0.5 */ +pa_operation* pa_context_set_name(pa_context *c, const char *name, pa_context_success_cb_t cb, void *userdata); + +/** Return the server name this context is connected to. \since 0.7 */ +const char* pa_context_get_server(pa_context *c); + +/** Return the protocol version of the library. \since 0.8 */ +uint32_t pa_context_get_protocol_version(pa_context *c); + +/** Return the protocol version of the connected server. \since 0.8 */ +uint32_t pa_context_get_server_protocol_version(pa_context *c); + +PA_C_DECL_END + +#endif -- cgit