Bug 1331648 - detect device connection for the case /dev/v4l hasn't existed; r=jesup

MozReview-Commit-ID: 1erqrFScjr

--HG--
extra : rebase_source : ad4a4adde64f479a84a3f7fa093f71eef319436b

media/webrtc/trunk/webrtc/modules/video_capture/linux/device_info_linux.cc

@@ -52,30 +52,57 @@ VideoCaptureImpl::CreateDeviceInfo(const int32_t id)
 }
 
 #ifdef WEBRTC_LINUX
-void DeviceInfoLinux::HandleEvent(inotify_event* event)
+void DeviceInfoLinux::HandleEvent(inotify_event* event, int fd)
 {
-    switch (event->mask) {
-        case IN_CREATE:
+    if (event->mask & IN_CREATE) {
+        if (fd == _fd_v4l || fd == _fd_snd) {
             DeviceChange();
-            break;
-        case IN_DELETE:
-            DeviceChange();
-            break;
-        default:
-            char* cur_event_filename = NULL;
-            int cur_event_wd = event->wd;
-            if (event->len) {
-                cur_event_filename = event->name;
+        } else if ((event->mask & IN_ISDIR) && (fd == _fd_dev)) {
+            if (_wd_v4l < 0) {
+                // Sometimes inotify_add_watch failed if we call it immediately after receiving this event
+                // Adding 5ms delay to let file system settle down
+                usleep(5*1000);
+                _wd_v4l = inotify_add_watch(_fd_v4l, "/dev/v4l/by-path/", IN_CREATE | IN_DELETE | IN_DELETE_SELF);
+                if (_wd_v4l >= 0) {
+                    DeviceChange();
+                }
             }
+            if (_wd_snd < 0) {
+                usleep(5*1000);
+                _wd_snd = inotify_add_watch(_fd_snd, "/dev/snd/by-path/", IN_CREATE | IN_DELETE | IN_DELETE_SELF);
+                if (_wd_snd >= 0) {
+                    DeviceChange();
+                }
+            }
+        }
+    } else if (event->mask & IN_DELETE) {
+        if (fd == _fd_v4l || fd == _fd_snd) {
+            DeviceChange();
+        }
+    } else if (event->mask & IN_DELETE_SELF) {
+        if (fd == _fd_v4l) {
+            inotify_rm_watch(_fd_v4l, _wd_v4l);
+            _wd_v4l = -1;
+        } else if (fd == _fd_snd) {
+            inotify_rm_watch(_fd_snd, _wd_snd);
+            _wd_snd = -1;
+        } else {
+            assert(false);
+        }
+    } else {
+        char* cur_event_filename = NULL;
+        int cur_event_wd = event->wd;
+        if (event->len) {
+            cur_event_filename = event->name;
+        }
 
-            WEBRTC_TRACE(webrtc::kTraceError, webrtc::kTraceVideoCapture, _id,
-                "UNKNOWN EVENT OCCURRED for file \"%s\" on WD #%i\n",
-                cur_event_filename, cur_event_wd);
-            break;
+        WEBRTC_TRACE(webrtc::kTraceError, webrtc::kTraceVideoCapture, _id,
+            "UNKNOWN EVENT OCCURRED for file \"%s\" on WD #%i\n",
+            cur_event_filename, cur_event_wd);
     }
 }
 
-int DeviceInfoLinux::EventCheck()
+int DeviceInfoLinux::EventCheck(int fd)
 {
     struct timeval timeout;
     fd_set rfds;
@@ -84,16 +111,16 @@ int DeviceInfoLinux::EventCheck()
     timeout.tv_usec = 100000;
 
     FD_ZERO(&rfds);
-    FD_SET(_fd, &rfds);
+    FD_SET(fd, &rfds);
 
-    return select(_fd+1, &rfds, NULL, NULL, &timeout);
+    return select(fd+1, &rfds, NULL, NULL, &timeout);
 }
 
-int DeviceInfoLinux::HandleEvents()
+int DeviceInfoLinux::HandleEvents(int fd)
 {
     char buffer[BUF_LEN];
 
-    ssize_t r = read(_fd, buffer, BUF_LEN);
+    ssize_t r = read(fd, buffer, BUF_LEN);
 
     if (r <= 0) {
         return r;
@@ -113,7 +140,7 @@ int DeviceInfoLinux::HandleEvents()
 
         memcpy(event, pevent, eventSize);
 
-        HandleEvent((inotify_event*)(event));
+        HandleEvent((inotify_event*)(event), fd);
 
         buffer_i += eventSize;
         count++;
@@ -125,8 +152,18 @@ int DeviceInfoLinux::HandleEvents()
 int DeviceInfoLinux::ProcessInotifyEvents()
 {
     while (0 == _isShutdown.Value()) {
-        if (EventCheck() > 0) {
-            if (HandleEvents() < 0) {
+        if (EventCheck(_fd_dev) > 0) {
+            if (HandleEvents(_fd_dev) < 0) {
+                break;
+            }
+        }
+        if (EventCheck(_fd_v4l) > 0) {
+            if (HandleEvents(_fd_v4l) < 0) {
+                break;
+            }
+        }
+        if (EventCheck(_fd_snd) > 0) {
+            if (HandleEvents(_fd_snd) < 0) {
                 break;
             }
         }
@@ -141,21 +178,30 @@ bool DeviceInfoLinux::InotifyEventThread(void* obj)
 
 bool DeviceInfoLinux::InotifyProcess()
 {
-    _fd = inotify_init();
-    if (_fd >= 0) {
-        _wd_v4l = inotify_add_watch(_fd, "/dev/v4l/by-path/", IN_CREATE | IN_DELETE);
-        _wd_snd = inotify_add_watch(_fd, "/dev/snd/by-path/", IN_CREATE | IN_DELETE);
+    _fd_v4l = inotify_init();
+    _fd_snd = inotify_init();
+    _fd_dev = inotify_init();
+    if (_fd_v4l >= 0 && _fd_snd >= 0 && _fd_dev >= 0) {
+        _wd_v4l = inotify_add_watch(_fd_v4l, "/dev/v4l/by-path/", IN_CREATE | IN_DELETE | IN_DELETE_SELF);
+        _wd_snd = inotify_add_watch(_fd_snd, "/dev/snd/by-path/", IN_CREATE | IN_DELETE | IN_DELETE_SELF);
+        _wd_dev = inotify_add_watch(_fd_dev, "/dev/", IN_CREATE);
         ProcessInotifyEvents();
 
         if (_wd_v4l >= 0) {
-          inotify_rm_watch(_fd, _wd_v4l);
+          inotify_rm_watch(_fd_v4l, _wd_v4l);
         }
 
         if (_wd_snd >= 0) {
-          inotify_rm_watch(_fd, _wd_snd);
+          inotify_rm_watch(_fd_snd, _wd_snd);
         }
 
-        close(_fd);
+        if (_wd_dev >= 0) {
+          inotify_rm_watch(_fd_dev, _wd_dev);
+        }
+
+        close(_fd_v4l);
+        close(_fd_snd);
+        close(_fd_dev);
         return true;
     } else {
         return false;

media/webrtc/trunk/webrtc/modules/video_capture/linux/device_info_linux.h

@@ -55,14 +55,14 @@ private:
     bool IsDeviceNameMatches(const char* name, const char* deviceUniqueIdUTF8);
 
 #ifdef WEBRTC_LINUX
-    void HandleEvent(inotify_event* event);
-    int EventCheck();
-    int HandleEvents();
+    void HandleEvent(inotify_event* event, int fd);
+    int EventCheck(int fd);
+    int HandleEvents(int fd);
     int ProcessInotifyEvents();
     rtc::scoped_ptr<rtc::PlatformThread> _inotifyEventThread;
     static bool InotifyEventThread(void*);
     bool InotifyProcess();
-    int _fd, _wd_v4l, _wd_snd; /* accessed on InotifyEventThread thread */
+    int _fd_v4l, _fd_snd, _fd_dev, _wd_v4l, _wd_snd, _wd_dev; /* accessed on InotifyEventThread thread */
     Atomic32 _isShutdown;
 #endif
 };