jackdbus: implement session command queue

dbus/controller.c

@@ -26,6 +26,7 @@
 #include <string.h>
 #include <dbus/dbus.h>
 #include <assert.h>
+#include <unistd.h>
 
 #include "controller.h"
 #include "controller_internal.h"
@@ -287,6 +288,15 @@ jack_controller_stop_server(
 {
     int ret;
 
+    pthread_mutex_lock(&controller_ptr->lock);
+    if (!list_empty(&controller_ptr->session_pending_commands))
+    {
+        pthread_mutex_unlock(&controller_ptr->lock);
+        jack_dbus_error(dbus_call_context_ptr, JACK_DBUS_ERROR_GENERIC, "Refusing to stop JACK server because of pending session commands");
+        return false;
+    }
+    pthread_mutex_unlock(&controller_ptr->lock);
+
     jack_info("Stopping jack server...");
 
     assert(controller_ptr->started); /* should be ensured by caller */
@@ -507,6 +517,7 @@ void *
 jack_controller_create(
         DBusConnection *connection)
 {
+    int error;
     struct jack_controller *controller_ptr;
     const char * address[PARAM_ADDRESS_SIZE];
     DBusObjectPathVTable vtable =
@@ -523,11 +534,20 @@ jack_controller_create(
         goto fail;
     }
 
+    error = pthread_mutex_init(&controller_ptr->lock, NULL);
+    if (error != 0)
+    {
+        jack_error("Failed to initialize mutex. error %d", error);
+        goto fail_free;
+    }
+
+    INIT_LIST_HEAD(&controller_ptr->session_pending_commands);
+
     controller_ptr->server = jackctl_server_create(on_device_acquire, on_device_release);
     if (controller_ptr->server == NULL)
     {
         jack_error("Failed to create server object");
-        goto fail_free;
+        goto fail_uninit_mutex;
     }
 
     controller_ptr->params = jack_params_create(controller_ptr->server);
@@ -585,6 +605,9 @@ fail_destroy_params:
 fail_destroy_server:
     jackctl_server_destroy(controller_ptr->server);
 
+fail_uninit_mutex:
+    pthread_mutex_destroy(&controller_ptr->lock);
+
 fail_free:
     free(controller_ptr);
 
@@ -739,13 +762,17 @@ jack_controller_destroy(
 {
     if (controller_ptr->started)
     {
-        jack_controller_stop_server(controller_ptr, NULL);
+        while (!jack_controller_stop_server(controller_ptr, NULL))
+        {
+            jack_info("jack server failed to stop, retrying in 3 seconds...");
+            usleep(3000000);
+        }
     }
 
     jack_controller_remove_slave_drivers(controller_ptr);
     jack_params_destroy(controller_ptr->params);
     jackctl_server_destroy(controller_ptr->server);
-
+    pthread_mutex_destroy(&controller_ptr->lock);
     free(controller_ptr);
 }
 

dbus/controller_iface_session_manager.c

@@ -30,69 +30,96 @@
 #include "jackdbus.h"
 #include "controller_internal.h"
 #include "jack/session.h"
+#include "common/JackError.h"
 
-#define controller_ptr ((struct jack_controller *)call->context)
+#define JACK_DBUS_IFACE_NAME "org.jackaudio.SessionManager"
 
 static
 void
-jack_controller_dbus_session_notify(
-    struct jack_dbus_method_call * call)
+jack_controller_control_send_signal_session_state_changed(
+    jack_session_event_type_t type,
+    const char * target)
 {
-    const char * target;
     dbus_uint32_t u32;
-    const char * path;
-    jack_session_event_type_t type;
-    jack_session_command_t * commands;
-    const jack_session_command_t * cmd_ptr;
-    DBusMessageIter top_iter, array_iter, struct_iter;
 
-    if (!jack_dbus_get_method_args(
-            call,
-            DBUS_TYPE_STRING,
-            &target,
-            DBUS_TYPE_UINT32,
-            &u32,
-            DBUS_TYPE_STRING,
-            &path,
-            DBUS_TYPE_INVALID))
+    u32 = type;
+    if (target == NULL)
     {
-        /* The method call had invalid arguments meaning that jack_dbus_get_method_args() has constructed an error for us. */
-        goto exit;
+        target = "";
     }
 
-    jack_info("Session notify initiated. target='%s', type=%"PRIu32", path='%s'", target, u32, path);
+    jack_dbus_send_signal(
+        JACK_CONTROLLER_OBJECT_PATH,
+        JACK_DBUS_IFACE_NAME,
+        "StateChanged",
+        DBUS_TYPE_UINT32,
+        &u32,
+        DBUS_TYPE_STRING,
+        &target,
+        DBUS_TYPE_INVALID);
+}
 
-    if (*target == 0)
+static bool start_detached_thread(void * (* start_routine)(void *), void * arg)
+{
+    int ret;
+    static pthread_attr_t attr;
+    pthread_t tid;
+
+    ret = pthread_attr_init(&attr);
+    if (ret != 0)
     {
-        target = NULL;
+        jack_error("pthread_attr_init() failed with %d", ret);
+        goto exit;
     }
 
-    type = (jack_session_event_type_t)u32;
+    ret = pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);
+    if (ret != 0)
+    {
+        jack_error("pthread_attr_setdetachstate() failed with %d", ret);
+        goto destroy_attr;
+    }
 
-    if (type != JackSessionSave &&
-        type != JackSessionSaveAndQuit &&
-        type != JackSessionSaveTemplate)
+    ret = pthread_create(&tid, &attr, start_routine, arg);
+    if (ret != 0)
     {
-        jack_dbus_error(call, JACK_DBUS_ERROR_INVALID_ARGS, "Invalid session event type %" PRIu32, u32);
-        goto exit;
+        jack_error("pthread_create() failed with %d", ret);
+        goto destroy_attr;
     }
 
-    commands = jack_session_notify(controller_ptr->client, target, type, path);
+    jack_log("Detached thread %d created", (int)tid);
+
+destroy_attr:
+    pthread_attr_destroy(&attr);
+exit:
+    return ret == 0;
+}
+
+static void send_session_notify_reply(struct jack_session_pending_command * pending_cmd_ptr, jack_session_command_t * commands)
+{
+    struct jack_dbus_method_call call;
+    const jack_session_command_t * cmd_ptr;
+    DBusMessageIter top_iter, array_iter, struct_iter;
+    dbus_uint32_t u32;
+
+    /* jack_dbus_error() wants call struct */
+    call.message = pending_cmd_ptr->message;
+    call.connection = pending_cmd_ptr->connection;
+
     if (commands == NULL)
     {
-        jack_dbus_error(call, JACK_DBUS_ERROR_GENERIC, "jack_session_notify() failed");
-        goto exit;
+        jack_dbus_error(&call, JACK_DBUS_ERROR_GENERIC, "jack_session_notify() failed");
+        goto send_reply;
     }
 
     jack_info("Session notify complete, commands follow:");
 
-    call->reply = dbus_message_new_method_return(call->message);
-    if (call->reply == NULL)
+    call.reply = dbus_message_new_method_return(pending_cmd_ptr->message);
+    if (call.reply == NULL)
     {
         goto oom;
     }
 
-    dbus_message_iter_init_append(call->reply, &top_iter);
+    dbus_message_iter_init_append(call.reply, &top_iter);
 
     if (!dbus_message_iter_open_container(&top_iter, DBUS_TYPE_ARRAY, "(sssu)", &array_iter))
     {
@@ -142,21 +169,180 @@ jack_controller_dbus_session_notify(
         goto unref;
     }
 
-    goto free;
+    goto send_reply;
 
 close_struct:
     dbus_message_iter_close_container(&array_iter, &struct_iter);
 close_array:
     dbus_message_iter_close_container(&top_iter, &array_iter);
 unref:
-    dbus_message_unref(call->reply);
-    call->reply = NULL;
+    dbus_message_unref(call.reply);
+    goto oom;
+
+send_reply:
+    if (call.reply != NULL)
+    {
+        if (!dbus_connection_send(pending_cmd_ptr->connection, call.reply, NULL))
+        {
+            jack_error("Ran out of memory trying to queue method return");
+        }
+
+        dbus_connection_flush(pending_cmd_ptr->connection);
+        dbus_message_unref(call.reply);
+    }
+    else
+    {
 oom:
-    jack_error("Ran out of memory trying to construct method return");
-free:
-    jack_session_commands_free(commands);
-exit:
-    return;
+        jack_error("Ran out of memory trying to construct method return");
+    }
+}
+
+#define controller_ptr ((struct jack_controller *)context)
+void * jack_controller_process_session_command_thread(void * context)
+{
+    struct jack_session_pending_command * pending_cmd_ptr;
+    jack_session_command_t * commands;
+
+    jack_log("jack_controller_process_session_command_thread enter");
+
+    pthread_mutex_lock(&controller_ptr->lock);
+loop:
+    /* get next command */
+    assert(!list_empty(&controller_ptr->session_pending_commands));
+    pending_cmd_ptr = list_entry(controller_ptr->session_pending_commands.next, struct jack_session_pending_command, siblings);
+    pthread_mutex_unlock(&controller_ptr->lock);
+
+    jack_info("Session notify initiated. target='%s', type=%d, path='%s'", pending_cmd_ptr->target, (int)pending_cmd_ptr->type, pending_cmd_ptr->path);
+
+    jack_controller_control_send_signal_session_state_changed(pending_cmd_ptr->type, pending_cmd_ptr->target);
+
+    commands = jack_session_notify(controller_ptr->client, pending_cmd_ptr->target, pending_cmd_ptr->type, pending_cmd_ptr->path);
+    usleep(5000000);
+    send_session_notify_reply(pending_cmd_ptr, commands);
+    if (commands != NULL)
+    {
+        jack_session_commands_free(commands);
+    }
+
+    pthread_mutex_lock(&controller_ptr->lock);
+
+    /* keep state consistent by sending signal after to lock */
+    /* otherwise the main thread may receive not-to-be-queued request and fail */
+    jack_controller_control_send_signal_session_state_changed(0, NULL);
+
+    /* remove the head of the list (queue) */
+    assert(!list_empty(&controller_ptr->session_pending_commands));
+    assert(pending_cmd_ptr == list_entry(controller_ptr->session_pending_commands.next, struct jack_session_pending_command, siblings));
+    list_del(&pending_cmd_ptr->siblings);
+
+    /* command cleanup */
+    dbus_message_unref(pending_cmd_ptr->message);
+    dbus_connection_ref(pending_cmd_ptr->connection);
+    free(pending_cmd_ptr);
+
+    /* If there are more commands, process them. Otherwise - exit the thread */
+    if (!list_empty(&controller_ptr->session_pending_commands))
+    {
+        goto loop;
+    }
+
+    pthread_mutex_unlock(&controller_ptr->lock);
+
+    jack_log("jack_controller_process_session_command_thread exit");
+    return NULL;
+}
+
+#undef controller_ptr
+#define controller_ptr ((struct jack_controller *)call->context)
+
+static
+void
+jack_controller_dbus_session_notify(
+    struct jack_dbus_method_call * call)
+{
+    dbus_bool_t queue;
+    const char * target;
+    dbus_uint32_t u32;
+    const char * path;
+    jack_session_event_type_t type;
+    struct jack_session_pending_command * cmd_ptr;
+
+    if (!controller_ptr->started)
+    {
+        jack_dbus_only_error(call, JACK_DBUS_ERROR_SERVER_NOT_RUNNING, "Can't execute method '%s' with stopped JACK server", call->method_name);
+        return;
+    }
+
+    if (!jack_dbus_get_method_args(
+            call,
+            DBUS_TYPE_BOOLEAN,
+            &queue,
+            DBUS_TYPE_STRING,
+            &target,
+            DBUS_TYPE_UINT32,
+            &u32,
+            DBUS_TYPE_STRING,
+            &path,
+            DBUS_TYPE_INVALID))
+    {
+        /* The method call had invalid arguments meaning that jack_dbus_get_method_args() has constructed an error for us. */
+        return;
+    }
+
+    if (*target == 0)
+    {
+        target = NULL;
+    }
+
+    type = (jack_session_event_type_t)u32;
+
+    if (type != JackSessionSave &&
+        type != JackSessionSaveAndQuit &&
+        type != JackSessionSaveTemplate)
+    {
+        jack_dbus_error(call, JACK_DBUS_ERROR_INVALID_ARGS, "Invalid session event type %" PRIu32, u32);
+        return;
+    }
+
+    pthread_mutex_lock(&controller_ptr->lock);
+    if (list_empty(&controller_ptr->session_pending_commands))
+    {
+        if (!start_detached_thread(jack_controller_process_session_command_thread, controller_ptr))
+        {
+            jack_dbus_error(call, JACK_DBUS_ERROR_GENERIC, "Cannot start thread to process the command");
+            goto unlock;
+        }
+
+        jack_log("Session notify thread started");
+    }
+    else if (!queue)
+    {
+        jack_dbus_error(call, JACK_DBUS_ERROR_GENERIC, "Busy");
+        goto unlock;
+    }
+
+    cmd_ptr = malloc(sizeof(struct jack_session_pending_command));
+    if (cmd_ptr == NULL)
+    {
+        jack_dbus_error(call, JACK_DBUS_ERROR_GENERIC, "malloc() failed for jack_session_pending_command struct");
+        goto unlock;
+    }
+
+    cmd_ptr->message = dbus_message_ref(call->message);
+    call->message = NULL; /* mark that reply will be sent asynchronously */
+    cmd_ptr->connection = dbus_connection_ref(call->connection);
+
+    /* it is safe to use the retrived pointers because we already made an additional message reference */
+    cmd_ptr->type = type;
+    cmd_ptr->target = target;
+    cmd_ptr->path = path;
+
+    list_add_tail(&cmd_ptr->siblings, &controller_ptr->session_pending_commands);
+
+    jack_log("Session notify scheduled. target='%s', type=%"PRIu32", path='%s'", target, u32, path);
+
+unlock:
+    pthread_mutex_unlock(&controller_ptr->lock);
 }
 
 static
@@ -278,9 +464,60 @@ jack_controller_dbus_has_session_callback(
     jack_dbus_construct_method_return_single(call, DBUS_TYPE_BOOLEAN, retval);
 }
 
+static
+void
+jack_controller_dbus_get_session_state(
+    struct jack_dbus_method_call * call)
+{
+    DBusMessageIter iter;
+    struct jack_session_pending_command * cmd_ptr;
+    const char * target;
+    dbus_uint32_t type;
+    bool append_failed;
+
+    call->reply = dbus_message_new_method_return(call->message);
+    if (call->reply == NULL)
+    {
+        goto oom;
+    }
+
+    dbus_message_iter_init_append(call->reply, &iter);
+
+    pthread_mutex_lock(&controller_ptr->lock);
+
+    if (list_empty(&controller_ptr->session_pending_commands))
+    {
+        type = 0;
+        target = "";
+    }
+    else
+    {
+        cmd_ptr = list_entry(controller_ptr->session_pending_commands.next, struct jack_session_pending_command, siblings);
+        type = (dbus_uint32_t)cmd_ptr->type;
+        target = cmd_ptr->target;
+    }
+
+    append_failed =
+        !dbus_message_iter_append_basic(&iter, DBUS_TYPE_UINT32, &type) ||
+        !dbus_message_iter_append_basic(&iter, DBUS_TYPE_STRING, &target);
+
+    pthread_mutex_unlock(&controller_ptr->lock);
+
+    if (!append_failed)
+    {
+        return;
+    }
+
+    dbus_message_unref(call->reply);
+    call->reply = NULL;
+oom:
+    jack_error("Ran out of memory trying to construct method return");
+}
+
 #undef controller_ptr
 
 JACK_DBUS_METHOD_ARGUMENTS_BEGIN(Notify)
+    JACK_DBUS_METHOD_ARGUMENT("queue", DBUS_TYPE_BOOLEAN_AS_STRING, false)
     JACK_DBUS_METHOD_ARGUMENT("target", DBUS_TYPE_STRING_AS_STRING, false)
     JACK_DBUS_METHOD_ARGUMENT("type", DBUS_TYPE_UINT32_AS_STRING, false)
     JACK_DBUS_METHOD_ARGUMENT("path", DBUS_TYPE_STRING_AS_STRING, false)
@@ -307,14 +544,30 @@ JACK_DBUS_METHOD_ARGUMENTS_BEGIN(HasSessionCallback)
     JACK_DBUS_METHOD_ARGUMENT("has_session_callback", DBUS_TYPE_BOOLEAN_AS_STRING, true)
 JACK_DBUS_METHOD_ARGUMENTS_END
 
+JACK_DBUS_METHOD_ARGUMENTS_BEGIN(GetState)
+    JACK_DBUS_METHOD_ARGUMENT("type", DBUS_TYPE_UINT32_AS_STRING, true)
+    JACK_DBUS_METHOD_ARGUMENT("target", DBUS_TYPE_STRING_AS_STRING, true)
+JACK_DBUS_METHOD_ARGUMENTS_END
+
+JACK_DBUS_SIGNAL_ARGUMENTS_BEGIN(StateChanged)
+    JACK_DBUS_SIGNAL_ARGUMENT("type", DBUS_TYPE_UINT32_AS_STRING)
+    JACK_DBUS_SIGNAL_ARGUMENT("target", DBUS_TYPE_STRING_AS_STRING)
+JACK_DBUS_SIGNAL_ARGUMENTS_END
+
 JACK_DBUS_METHODS_BEGIN
     JACK_DBUS_METHOD_DESCRIBE(Notify, jack_controller_dbus_session_notify)
     JACK_DBUS_METHOD_DESCRIBE(GetUuidForClientName, jack_controller_dbus_get_uuid_for_client_name)
     JACK_DBUS_METHOD_DESCRIBE(GetClientNameByUuid, jack_controller_dbus_get_client_name_by_uuid)
     JACK_DBUS_METHOD_DESCRIBE(ReserveClientName, jack_controller_dbus_reserve_client_name)
     JACK_DBUS_METHOD_DESCRIBE(HasSessionCallback, jack_controller_dbus_has_session_callback)
+    JACK_DBUS_METHOD_DESCRIBE(GetState, jack_controller_dbus_get_session_state)
 JACK_DBUS_METHODS_END
 
-JACK_DBUS_IFACE_BEGIN(g_jack_controller_iface_session_manager, "org.jackaudio.SessionManager")
+JACK_DBUS_SIGNALS_BEGIN
+    JACK_DBUS_SIGNAL_DESCRIBE(StateChanged)
+JACK_DBUS_SIGNALS_END
+
+JACK_DBUS_IFACE_BEGIN(g_jack_controller_iface_session_manager, JACK_DBUS_IFACE_NAME)
     JACK_DBUS_IFACE_EXPOSE_METHODS
+    JACK_DBUS_IFACE_EXPOSE_SIGNALS
 JACK_DBUS_IFACE_END

dbus/controller_internal.h

@@ -25,6 +25,7 @@
 #include "jslist.h"
 #include "jack/control.h"
 #include "jack/jack.h"
+#include "jack/session.h"
 #include "jackdbus.h"
 #include "list.h"
 #include "params.h"
@@ -37,6 +38,16 @@ struct jack_controller_slave_driver
     bool loaded;
 };
 
+struct jack_session_pending_command
+{
+    struct list_head siblings;
+    DBusConnection * connection;
+    DBusMessage * message;
+    jack_session_event_type_t type;
+    const char * target;
+    const char * path;
+};
+
 struct jack_controller
 {
     jackctl_server_t *server;
@@ -54,6 +65,9 @@ struct jack_controller
     union jackctl_parameter_value slave_drivers_vparam_value;
 
     struct jack_dbus_object_descriptor dbus_descriptor;
+
+    pthread_mutex_t lock;
+    struct list_head session_pending_commands;
 };
 
 #define DEFAULT_DRIVER "dummy"

dbus/jackdbus.c

@@ -105,6 +105,12 @@ void
 jack_dbus_send_method_return(
     struct jack_dbus_method_call * call)
 {
+    if (call->message == NULL)
+    {
+        /* async call */
+        return;
+    }
+
     if (call->reply)
     {
     retry_send: