gstreamer/subprojects/gst-plugins-bad/sys/mediafoundation/gstwin32devicewatcher.cpp

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/* GStreamer
* Copyright (C) 2021 Seungha Yang <seungha@centricular.com>
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Library General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library 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
* Library General Public License for more details.
*
* You should have received a copy of the GNU Library General Public
* License along with this library; if not, write to the
* Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
* Boston, MA 02110-1301, USA.
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include "gstwin32devicewatcher.h"
#include <dbt.h>
GST_DEBUG_CATEGORY_STATIC (gst_win32_device_watcher_debug);
#define GST_CAT_DEFAULT gst_win32_device_watcher_debug
G_LOCK_DEFINE_STATIC (create_lock);
#define GST_WIN32_HWND_PROP_NAME "gst-win32-device-watcher"
struct _GstWin32DeviceWatcher
{
GstObject parent;
GMutex lock;
GCond cond;
GThread *thread;
GMainContext *context;
GMainLoop *loop;
GstWin32DeviceWatcherCallbacks callbacks;
gpointer user_data;
HDEVNOTIFY device_notify;
HWND hwnd;
DWORD device_type;
GUID class_guid;
};
#define gst_win32_device_watcher_parent_class parent_class
G_DEFINE_TYPE (GstWin32DeviceWatcher, gst_win32_device_watcher,
GST_TYPE_OBJECT);
static void gst_win32_device_watcher_constructed (GObject * object);
static void gst_win32_device_watcher_finalize (GObject * object);
static gpointer
gst_win32_device_watcher_thread_func (GstWin32DeviceWatcher * self);
static void
gst_win32_device_watcher_class_init (GstWin32DeviceWatcherClass * klass)
{
GObjectClass *gobject_class = G_OBJECT_CLASS (klass);
gobject_class->constructed = gst_win32_device_watcher_constructed;
gobject_class->finalize = gst_win32_device_watcher_finalize;
GST_DEBUG_CATEGORY_INIT (gst_win32_device_watcher_debug,
"win32devicewatcher", 0, "win32devicewatcher");
}
static void
gst_win32_device_watcher_init (GstWin32DeviceWatcher * self)
{
g_mutex_init (&self->lock);
g_cond_init (&self->cond);
self->context = g_main_context_new ();
self->loop = g_main_loop_new (self->context, FALSE);
}
static void
gst_win32_device_watcher_constructed (GObject * object)
{
GstWin32DeviceWatcher *self = GST_WIN32_DEVICE_WATCHER (object);
/* Create a new thread for WIN32 message pumping */
g_mutex_lock (&self->lock);
self->thread = g_thread_new ("GstWin32DeviceWatcher",
(GThreadFunc) gst_win32_device_watcher_thread_func, self);
while (!g_main_loop_is_running (self->loop))
g_cond_wait (&self->cond, &self->lock);
g_mutex_unlock (&self->lock);
}
static void
gst_win32_device_watcher_finalize (GObject * object)
{
GstWin32DeviceWatcher *self = GST_WIN32_DEVICE_WATCHER (object);
g_main_loop_quit (self->loop);
if (g_thread_self () != self->thread) {
g_thread_join (self->thread);
g_main_loop_unref (self->loop);
g_main_context_unref (self->context);
} else {
g_warning ("Trying join from self-thread");
}
g_mutex_clear (&self->lock);
g_cond_clear (&self->cond);
G_OBJECT_CLASS (parent_class)->finalize (object);
}
static LRESULT CALLBACK
window_proc (HWND hwnd, UINT msg, WPARAM wparam, LPARAM lparam)
{
GstWin32DeviceWatcher *self;
switch (msg) {
case WM_CREATE:
self = (GstWin32DeviceWatcher *)
((LPCREATESTRUCT) lparam)->lpCreateParams;
GST_DEBUG_OBJECT (self, "WM_CREATE");
SetPropA (hwnd, GST_WIN32_HWND_PROP_NAME, self);
break;
case WM_DEVICECHANGE:
{
self = (GstWin32DeviceWatcher *) GetPropA
(hwnd, GST_WIN32_HWND_PROP_NAME);
if (!self) {
GST_WARNING ("Failed to get watcher object");
break;
}
self->callbacks.device_changed (self, wparam, lparam, self->user_data);
break;
}
default:
break;
}
return DefWindowProc (hwnd, msg, wparam, lparam);
}
static HWND
create_hwnd (GstWin32DeviceWatcher * self)
{
WNDCLASSEXA wc;
ATOM atom = 0;
HINSTANCE hinstance = GetModuleHandle (nullptr);
static const gchar *klass_name = "GstWin32DeviceWatcher";
HWND hwnd;
G_LOCK (create_lock);
atom = GetClassInfoExA (hinstance, klass_name, &wc);
if (atom == 0) {
GST_LOG_OBJECT (self, "Register window class");
ZeroMemory (&wc, sizeof (WNDCLASSEX));
wc.cbSize = sizeof (WNDCLASSEXA);
wc.lpfnWndProc = window_proc;
wc.hInstance = hinstance;
wc.lpszClassName = klass_name;
atom = RegisterClassExA (&wc);
if (atom == 0) {
G_UNLOCK (create_lock);
GST_ERROR_OBJECT (self, "Failed to register window class, lastError 0x%x",
(guint) GetLastError ());
return nullptr;
}
} else {
GST_LOG_OBJECT (self, "window class was already registered");
}
G_UNLOCK (create_lock);
hwnd = CreateWindowExA (0, klass_name, "", 0, 0, 0, 0, 0,
HWND_MESSAGE, nullptr, hinstance, self);
if (!hwnd) {
GST_ERROR_OBJECT (self, "Failed to create window handle, lastError 0x%x",
(guint) GetLastError ());
return nullptr;
}
return hwnd;
}
static gboolean
loop_running_cb (GstWin32DeviceWatcher * self)
{
g_mutex_lock (&self->lock);
g_cond_signal (&self->cond);
g_mutex_unlock (&self->lock);
return G_SOURCE_REMOVE;
}
static gboolean
win32_msg_cb (GIOChannel * source, GIOCondition condition, gpointer data)
{
MSG msg;
if (!PeekMessage (&msg, nullptr, 0, 0, PM_REMOVE))
return G_SOURCE_CONTINUE;
TranslateMessage (&msg);
DispatchMessage (&msg);
return G_SOURCE_CONTINUE;
}
static gpointer
gst_win32_device_watcher_thread_func (GstWin32DeviceWatcher * self)
{
GSource *idle_source;
HWND hwnd = nullptr;
GIOChannel *msg_io_channel = nullptr;
GSource *msg_source = nullptr;
g_main_context_push_thread_default (self->context);
idle_source = g_idle_source_new ();
g_source_set_callback (idle_source,
(GSourceFunc) loop_running_cb, self, nullptr);
g_source_attach (idle_source, self->context);
g_source_unref (idle_source);
hwnd = create_hwnd (self);
if (!hwnd)
goto run_loop;
msg_io_channel = g_io_channel_win32_new_messages ((gsize) hwnd);
msg_source = g_io_create_watch (msg_io_channel, G_IO_IN);
g_source_set_callback (msg_source,
(GSourceFunc) win32_msg_cb, nullptr, nullptr);
g_source_attach (msg_source, self->context);
self->hwnd = hwnd;
run_loop:
GST_INFO_OBJECT (self, "Starting loop");
g_main_loop_run (self->loop);
GST_INFO_OBJECT (self, "Stopped loop");
if (self->device_notify) {
UnregisterDeviceNotification (self->device_notify);
self->device_notify = nullptr;
}
if (msg_source) {
g_source_destroy (msg_source);
g_source_unref (msg_source);
}
if (msg_io_channel)
g_io_channel_unref (msg_io_channel);
if (hwnd)
DestroyWindow (hwnd);
g_main_context_pop_thread_default (self->context);
return nullptr;
}
GstWin32DeviceWatcher *
gst_win32_device_watcher_new (DWORD device_type, const GUID * class_guid,
const GstWin32DeviceWatcherCallbacks * callbacks, gpointer user_data)
{
GstWin32DeviceWatcher *self;
g_return_val_if_fail (class_guid != nullptr, nullptr);
g_return_val_if_fail (callbacks != nullptr, nullptr);
self = (GstWin32DeviceWatcher *)
g_object_new (GST_TYPE_WIN32_DEVICE_WATCHER, nullptr);
if (!self->hwnd) {
gst_object_unref (self);
return nullptr;
}
self->callbacks = *callbacks;
self->user_data = user_data;
self->device_type = device_type;
self->class_guid = *class_guid;
gst_object_ref_sink (self);
return self;
}
typedef struct
{
GstWin32DeviceWatcher *self;
gboolean handled;
gboolean ret;
} DeviceNotificationData;
static gboolean
register_device_notification (DeviceNotificationData * data)
{
GstWin32DeviceWatcher *self = data->self;
DEV_BROADCAST_DEVICEINTERFACE di = { 0, };
if (self->device_notify)
goto out;
di.dbcc_size = sizeof (di);
di.dbcc_devicetype = self->device_type;
di.dbcc_classguid = self->class_guid;
self->device_notify = RegisterDeviceNotificationW (self->hwnd,
&di, DEVICE_NOTIFY_WINDOW_HANDLE);
out:
if (self->device_notify)
data->ret = TRUE;
g_mutex_lock (&self->lock);
data->handled = TRUE;
g_cond_broadcast (&self->cond);
g_mutex_unlock (&self->lock);
return G_SOURCE_REMOVE;
}
gboolean
gst_win32_device_watcher_start (GstWin32DeviceWatcher * watcher)
{
DeviceNotificationData data;
g_return_val_if_fail (GST_IS_WIN32_DEVICE_WATCHER (watcher), FALSE);
data.self = watcher;
data.handled = FALSE;
data.ret = FALSE;
g_main_context_invoke (watcher->context,
(GSourceFunc) register_device_notification, &data);
g_mutex_lock (&watcher->lock);
while (!data.handled)
g_cond_wait (&watcher->cond, &watcher->lock);
g_mutex_unlock (&watcher->lock);
return data.ret;
}
static gboolean
unregister_device_notification (DeviceNotificationData * data)
{
GstWin32DeviceWatcher *self = data->self;
if (!self->device_notify)
goto out;
UnregisterDeviceNotification (self->device_notify);
self->device_notify = nullptr;
out:
g_mutex_lock (&self->lock);
data->handled = TRUE;
g_cond_broadcast (&self->cond);
g_mutex_unlock (&self->lock);
return G_SOURCE_REMOVE;
}
void
gst_win32_device_watcher_stop (GstWin32DeviceWatcher * watcher)
{
DeviceNotificationData data;
g_return_if_fail (GST_IS_WIN32_DEVICE_WATCHER (watcher));
data.self = watcher;
data.handled = FALSE;
g_main_context_invoke (watcher->context,
(GSourceFunc) register_device_notification, &data);
g_mutex_lock (&watcher->lock);
while (!data.handled)
g_cond_wait (&watcher->cond, &watcher->lock);
g_mutex_unlock (&watcher->lock);
}