add missing session.h file

common/jack/session.h

@@ -0,0 +1,229 @@
+/*
+    Copyright (C) 2001 Paul Davis
+    Copyright (C) 2004 Jack O'Quin
+    Copyright (C) 2010 Torben Hohn
+    
+    This program 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.
+    
+    This program 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 Lesser General Public License for more details.
+    
+    You should have received a copy of the GNU Lesser General Public License
+    along with this program; if not, write to the Free Software 
+    Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+
+*/
+
+#ifndef __jack_session_h__
+#define __jack_session_h__
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#include <jack/types.h>
+#include <jack/weakmacros.h>
+
+/**
+ * @defgroup SessionClientFunctions Session API for clients.
+ * @{
+ */
+
+
+/**
+ * session event types.
+ *
+ * if a client cant save templates, i might just do a normal save.
+ *
+ * the rationale, why there is no quit without save, is that a client
+ * might refuse to quit when it has unsaved data.
+ * however some other clients might have already quit.
+ * this results in too much confusion, so we just dont support that.
+ * the session manager can check, if the saved state is different from a previous
+ * save, and just remove the saved stuff.
+ *
+ * (an inquiry function, whether a quit is ok, followed by a quit event
+ *  would have a race)
+ */
+enum JackSessionEventType {
+    JackSessionSave = 1,
+    JackSessionSaveAndQuit = 2,
+    JackSessionSaveTemplate = 3
+};
+
+typedef enum JackSessionEventType jack_session_event_type_t;
+
+enum JackSessionFlags {
+    /**
+     * an error occured while saving.
+     */
+    JackSessionSaveError = 0x01,
+
+    /**
+     * this reply indicates that a client is part of a multiclient application.
+     * the command reply is left empty. but the session manager should still
+     * consider this client part of a session. it will come up due to invocation of another
+     * client.
+     */
+    JackSessionChildClient = 0x02
+};
+
+typedef enum JackSessionFlags jack_session_flags_t;
+
+struct _jack_session_event {
+    /**
+     * the actual type of this session event.
+     */
+    jack_session_event_type_t type;
+
+    /**
+     * session_directory with trailing separator
+     * this is per client. so the client can do whatever it likes in here.
+     */
+    const char *session_dir;
+
+    /**
+     * client_uuid which must be specified to jack_client_open on session reload.
+     * client can specify it in the returned commandline as an option, or just save it
+     * with the state file.
+     */
+    const char *client_uuid;
+
+    /**
+     * the command_line is the reply of the client.
+     * it specifies in a platform dependent way, how the client must be restarted upon session reload.
+     *
+     * probably it should contain ${SESSION_DIR} instead of the actual session dir.
+     * this would basically make the session dir moveable.
+     *
+     * ownership of the memory is handed to jack.
+     * initially set to NULL by jack;
+     */
+    char *command_line;
+
+    /**
+     * flags to be set by the client. normally left 0.
+     */
+    jack_session_flags_t flags;
+};
+
+typedef struct _jack_session_event jack_session_event_t;
+
+/**
+ * Prototype for the client supplied function that is called
+ * whenever a session notification is sent via jack_session_notify().
+ *
+ * The session_id must be passed to jack_client_open on session reload (this can be
+ * done by specifying it somehow on the returned command line).
+ *
+ * @param event the event_structure.
+ * @param arg pointer to a client supplied structure
+ */
+typedef void (*JackSessionCallback)(jack_session_event_t *event, void *arg);
+
+/**
+ * Tell the JACK server to call @a save_callback the session handler wants
+ * to save.
+ *
+ * @return 0 on success, otherwise a non-zero error code
+ */
+int jack_set_session_callback(jack_client_t *client,
+			    JackSessionCallback session_callback,
+			    void *arg) JACK_WEAK_EXPORT;
+
+/**
+ * reply to a session_event
+ *
+ * this can either be called directly from the callback, or later from a different thread.
+ * so its possible to just stick the event pointer into a pipe and execute the save code
+ * from the gui thread.
+ *
+ * @return 0 on success, otherwise a non-zero error code
+ */
+
+int jack_session_reply( jack_client_t *client, jack_session_event_t *event ) JACK_WEAK_EXPORT;
+
+
+/**
+ * free memory used by a jack_session_event_t
+ * this also frees the memory used by the command_line pointer.
+ * if its non NULL.
+ */
+
+void jack_session_event_free (jack_session_event_t *event);
+
+/*@}*/
+
+
+/**
+ * @defgroup JackSessionManagerAPI  this API is intended for a sessionmanager.
+ *				    this API could be server specific. if we dont reach consensus here,
+ *				    we can just drop it.
+ *				    i know its a bit clumsy.
+ *				    but this api isnt required to be as stable as the client api.
+ * @{
+ */
+
+typedef struct  {
+	const char *uuid;
+	const char *client_name;
+	const char *command;
+	jack_session_flags_t flags;
+} jack_session_command_t;
+
+/**
+ * send a save or quit event, to all clients listening for session
+ * callbacks. the returned strings of the clients are accumulated and
+ * returned as an array of jack_session_command_t.
+ * its terminated by ret[i].uuid == NULL
+ * target == NULL means send to all interested clients. otherwise a clientname
+ */
+
+jack_session_command_t *jack_session_notify (jack_client_t* client,
+					     const char *target,
+					     jack_session_event_type_t type,
+					     const char *path ) JACK_WEAK_EXPORT;
+
+/**
+ * free the memory allocated by a session command.
+ */
+
+void jack_session_commands_free (jack_session_command_t *cmds) JACK_WEAK_EXPORT;
+
+/**
+ * get the sessionid for a client name.
+ * the sessionmanager needs this to reassociate a client_name to the session_id.
+ */
+
+char *jack_get_uuid_for_client_name( jack_client_t *client, const char *client_name ) JACK_WEAK_EXPORT;
+
+/**
+ * get the client name for a session_id.
+ * in order to snapshot the graph connections, the sessionmanager needs to map
+ * session_ids to client names.
+ */
+
+char *jack_get_client_name_by_uuid( jack_client_t *client, const char *client_uuid ) JACK_WEAK_EXPORT;
+
+/**
+ * reserve a client name and associate it to a uuid.
+ * when a client later call jack_client_open() and specifies the uuid,
+ * jackd will assign the reserved name.
+ * this allows a session manager to know in advance under which client name
+ * its managed clients will appear.
+ *
+ * @return 0 on success, otherwise a non-zero error code
+ */
+
+int
+jack_reserve_client_name( jack_client_t *client, const char *name, const char *uuid ) JACK_WEAK_EXPORT;
+
+#ifdef __cplusplus
+}
+#endif
+#endif