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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-27 16:03:18 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-27 16:03:18 +0000 |
commit | 2dd5bc6a074165ddfbd57c4bd52c2d2dac8f47a1 (patch) | |
tree | 465b29cb405d3af0b0ad50c78e1dccc636594fec /src/pulse/context.h | |
parent | Initial commit. (diff) | |
download | pulseaudio-2dd5bc6a074165ddfbd57c4bd52c2d2dac8f47a1.tar.xz pulseaudio-2dd5bc6a074165ddfbd57c4bd52c2d2dac8f47a1.zip |
Adding upstream version 14.2.upstream/14.2upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'src/pulse/context.h')
-rw-r--r-- | src/pulse/context.h | 295 |
1 files changed, 295 insertions, 0 deletions
diff --git a/src/pulse/context.h b/src/pulse/context.h new file mode 100644 index 0000000..38656f8 --- /dev/null +++ b/src/pulse/context.h @@ -0,0 +1,295 @@ +#ifndef foocontexthfoo +#define foocontexthfoo + +/*** + This file is part of PulseAudio. + + Copyright 2004-2006 Lennart Poettering + Copyright 2006 Pierre Ossman <ossman@cendio.se> for Cendio AB + + 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 2.1 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, see <http://www.gnu.org/licenses/>. +***/ + +#include <pulse/sample.h> +#include <pulse/def.h> +#include <pulse/mainloop-api.h> +#include <pulse/cdecl.h> +#include <pulse/operation.h> +#include <pulse/proplist.h> +#include <pulse/version.h> + +/** \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 functionality. This however 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 Timer events - Events that trigger after a fixed amount 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 amount 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 PulseAudio's + * internal handling runs in a separate + * thread. + * \li \subpage glib-mainloop - A wrapper around GLib's main loop. + * + * 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 object's 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 asynchronous communication with a + * server. A pa_context object wraps a connection to a PulseAudio + * server using its native protocol. + * + * See also \subpage async + */ + +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); + +/** A callback for asynchronous meta/policy event messages. The set + * of defined events can be extended at any time. Also, server modules + * may introduce additional message types so make sure that your + * callback function ignores messages it doesn't know. \since + * 0.9.15 */ +typedef void (*pa_context_event_cb_t)(pa_context *c, const char *name, pa_proplist *p, void *userdata); + +/** Instantiate a new connection context with an abstract mainloop API + * and an application name. It is recommended to use pa_context_new_with_proplist() + * instead and specify some initial properties.*/ +pa_context *pa_context_new(pa_mainloop_api *mainloop, const char *name); + +/** Instantiate a new connection context with an abstract mainloop API + * and an application name, and specify the initial client property + * list. \since 0.9.11 */ +pa_context *pa_context_new_with_proplist(pa_mainloop_api *mainloop, const char *name, const pa_proplist *proplist); + +/** 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); + +/** Set a callback function that is called whenever a meta/policy + * control event is received. \since 0.9.15 */ +void pa_context_set_event_callback(pa_context *p, pa_context_event_cb_t cb, void *userdata); + +/** Return the error number of the last failed operation */ +int pa_context_errno(const pa_context *c); + +/** Return non-zero if some data is pending to be written to the connection */ +int pa_context_is_pending(const pa_context *c); + +/** Return the current context status */ +pa_context_state_t pa_context_get_state(const 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_CONTEXT_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. Returns negative on certain errors such as invalid state + * or parameters. */ +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 successfully, 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. */ +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. */ +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. */ +int pa_context_is_local(const pa_context *c); + +/** Set a different application name for context on the server. */ +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. */ +const char* pa_context_get_server(const pa_context *c); + +/** Return the protocol version of the library. */ +uint32_t pa_context_get_protocol_version(const pa_context *c); + +/** Return the protocol version of the connected server. + * Returns PA_INVALID_INDEX on error. */ +uint32_t pa_context_get_server_protocol_version(const pa_context *c); + +/** Update the property list of the client, adding new entries. Please + * note that it is highly recommended to set as many properties + * initially via pa_context_new_with_proplist() as possible instead a + * posteriori with this function, since that information may then be + * used to route streams of the client to the right device. \since 0.9.11 */ +pa_operation *pa_context_proplist_update(pa_context *c, pa_update_mode_t mode, const pa_proplist *p, pa_context_success_cb_t cb, void *userdata); + +/** Update the property list of the client, remove entries. \since 0.9.11 */ +pa_operation *pa_context_proplist_remove(pa_context *c, const char *const keys[], pa_context_success_cb_t cb, void *userdata); + +/** Return the client index this context is + * identified in the server with. This is useful for usage with the + * introspection functions, such as pa_context_get_client_info(). + * Returns PA_INVALID_INDEX on error. \since 0.9.11 */ +uint32_t pa_context_get_index(const pa_context *s); + +/** Create a new timer event source for the specified time (wrapper + * for mainloop->time_new). \since 0.9.16 */ +pa_time_event* pa_context_rttime_new(const pa_context *c, pa_usec_t usec, pa_time_event_cb_t cb, void *userdata); + +/** Restart a running or expired timer event source (wrapper for + * mainloop->time_restart). \since 0.9.16 */ +void pa_context_rttime_restart(const pa_context *c, pa_time_event *e, pa_usec_t usec); + +/** Return the optimal block size for passing around audio buffers. It + * is recommended to allocate buffers of the size returned here when + * writing audio data to playback streams, if the latency constraints + * permit this. It is not recommended writing larger blocks than this + * because usually they will then be split up internally into chunks + * of this size. It is not recommended writing smaller blocks than + * this (unless required due to latency demands) because this + * increases CPU usage. If ss is NULL you will be returned the + * byte-exact tile size. if ss is invalid, (size_t) -1 will be + * returned. If you pass a valid ss, then the tile size + * will be rounded down to multiple of the frame size. This is + * supposed to be used in a construct such as + * pa_context_get_tile_size(pa_stream_get_context(s), + * pa_stream_get_sample_spec(ss)); \since 0.9.20 */ +size_t pa_context_get_tile_size(const pa_context *c, const pa_sample_spec *ss); + +/** Load the authentication cookie from a file. This function is primarily + * meant for PulseAudio's own tunnel modules, which need to load the cookie + * from a custom location. Applications don't usually need to care about the + * cookie at all, but if it happens that you know what the authentication + * cookie is and your application needs to load it from a non-standard + * location, feel free to use this function. \since 5.0 */ +int pa_context_load_cookie_from_file(pa_context *c, const char *cookie_file_path); + +PA_C_DECL_END + +#endif |