add asynchronous inter-thread notification API

git-svn-id: file:///home/lennart/svn/public/pulseaudio/trunk@1402 fefdeb5f-60dc-0310-8127-8f9354f1896f

src/pulsecore/anotify.c

@@ -0,0 +1,143 @@
+/* $Id$ */
+
+/***
+  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 2.1 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
+  Lesser 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.
+***/
+
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
+
+#include <assert.h>
+#include <unistd.h>
+#include <fcntl.h>
+
+#include <pulse/xmalloc.h>
+
+#include "anotify.h"
+
+#define EVENTS_MAX 16
+
+struct pa_anotify {
+    pa_mainloop_api *api;
+    pa_anotify_cb_t callback;
+    void *userdata;
+    int fds[2];
+    pa_io_event *io_event;
+    pa_defer_event *defer_event;
+
+    uint8_t queued_events[EVENTS_MAX];
+    unsigned n_queued_events, queue_index;
+};
+
+static void dispatch_event(pa_anotify *a) {
+    assert(a);
+    assert(a->queue_index < a->n_queued_events);
+    
+    a->callback(a->queued_events[a->queue_index++], a->userdata);
+
+    if (a->queue_index >= a->n_queued_events) {
+        a->n_queued_events = 0;
+        a->queue_index = 0;
+
+        a->api->io_enable(a->io_event, PA_IO_EVENT_INPUT);
+        a->api->defer_enable(a->defer_event, 0);
+    } else {
+        a->api->io_enable(a->io_event, 0);
+        a->api->defer_enable(a->defer_event, 1);
+    }
+}
+
+static void io_callback(
+        pa_mainloop_api *api,
+        pa_io_event *e,
+        int fd,
+        pa_io_event_flags_t events,
+        void *userdata) {
+    
+    pa_anotify *a = userdata;
+    ssize_t r;
+
+    assert(a);
+    assert(events == PA_IO_EVENT_INPUT);
+    assert(a->n_queued_events == 0);
+    
+    r = read(fd, a->queued_events, sizeof(a->queued_events));
+    assert(r > 0);
+
+    a->n_queued_events = (unsigned) r;
+    a->queue_index = 0;
+
+    /* Only dispatch a single event */
+    dispatch_event(a);
+}
+
+static void defer_callback(pa_mainloop_api *api, pa_defer_event *e, void *userdata) {
+    pa_anotify *a = userdata;
+    assert(a);
+
+    dispatch_event(a);
+}
+
+pa_anotify *pa_anotify_new(pa_mainloop_api*api, pa_anotify_cb_t cb, void *userdata) {
+    pa_anotify *a;
+    
+    assert(api);
+    assert(cb);
+
+    a = pa_xnew(pa_anotify, 1);
+
+    if (pipe(a->fds) < 0) {
+        pa_xfree(a);
+        return NULL;
+    }
+    
+    a->api = api;
+    a->callback = cb;
+    a->userdata = userdata;
+
+    a->io_event = api->io_new(api, a->fds[0], PA_IO_EVENT_INPUT, io_callback, a);
+    a->defer_event = api->defer_new(api, defer_callback, a);
+    a->api->defer_enable(a->defer_event, 0);
+
+    a->n_queued_events = 0;
+
+    return a;
+}
+
+void pa_anotify_free(pa_anotify *a) {
+    assert(a);
+
+    a->api->io_free(a->io_event);
+    a->api->defer_free(a->defer_event);
+
+    if (a->fds[0] >= 0)
+        close(a->fds[0]);
+    if (a->fds[1] >= 0)
+        close(a->fds[1]);
+    
+    pa_xfree(a);
+}
+
+int pa_anotify_signal(pa_anotify *a, uint8_t event) {
+    ssize_t r;
+    assert(a);
+
+    r = write(a->fds[1], &event, 1);
+    return r != 1 ? -1 : 0;
+}

src/pulsecore/anotify.h

@@ -0,0 +1,38 @@
+#ifndef foopulseanotifyhfoo
+#define foopulseanotifyhfoo
+
+/* $Id$ */
+
+/***
+  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.
+***/
+
+/* Asynchronous thread-safe notification of mainloops */
+
+
+#include <inttypes.h>
+#include <pulse/mainloop-api.h>
+
+typedef struct pa_anotify pa_anotify;
+typedef void (*pa_anotify_cb_t)(uint8_t event, void *userdata);
+
+pa_anotify *pa_anotify_new(pa_mainloop_api*api, pa_anotify_cb_t cb, void *userdata);
+void pa_anotify_free(pa_anotify *a);
+int pa_anotify_signal(pa_anotify *a, uint8_t event);
+
+#endif