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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-27 16:03:18 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-27 16:03:18 +0000
commit2dd5bc6a074165ddfbd57c4bd52c2d2dac8f47a1 (patch)
tree465b29cb405d3af0b0ad50c78e1dccc636594fec /src/pulse/context.h
parentInitial commit. (diff)
downloadpulseaudio-2dd5bc6a074165ddfbd57c4bd52c2d2dac8f47a1.tar.xz
pulseaudio-2dd5bc6a074165ddfbd57c4bd52c2d2dac8f47a1.zip
Adding upstream version 14.2.upstream/14.2upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
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+#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