OSX, input: implement wakeup in response to Cocoa events

Add code to wake up the select() call in input.c when an OSX event is
available and a Cocoa OpenGL backend is initialized.

Fixes the slow response to input or other events in Cocoa-based VOs
during long select() sleeps (e.g., when mplayer2 is paused) introduced
by commit 7040968.

2 files changed, 167 insertions, 0 deletions

diff --git a/osdep/cocoa_events.h b/osdep/cocoa_events.h
new file mode 100644
index 0000000000..3f0e775e03
--- /dev/null
+++ b/osdep/cocoa_events.h
@@ -0,0 +1,30 @@
+/*
+ * Cocoa Event Handling
+ *
+ * This file is part of mplayer2.
+ *
+ * mplayer2 is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * mplayer2 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 General Public License along
+ * with mplayer2.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef MPLAYER_COCOA_EVENTS_H
+#define MPLAYER_COCOA_EVENTS_H
+
+#include "input/input.h"
+
+void cocoa_events_init(struct input_ctx *ictx,
+    void (*read_all_fd_events)(struct input_ctx *ictx, int time));
+void cocoa_events_uninit(void);
+void cocoa_events_read_all_events(struct input_ctx *ictx, int time);
+
+#endif /* MPLAYER_COCOA_EVENTS_H */
diff --git a/osdep/cocoa_events.m b/osdep/cocoa_events.m
new file mode 100644
index 0000000000..ba09c13cad
--- /dev/null
+++ b/osdep/cocoa_events.m
@@ -0,0 +1,137 @@
+/*
+ * Cocoa Event Handling
+ *
+ * This file is part of mplayer2.
+ *
+ * mplayer2 is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * mplayer2 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 General Public License along
+ * with mplayer2. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+/*
+ * Implementation details:
+ * This file deals with custom event polling on MacOSX. When mplayer2 is paused
+ * it will asynchronously poll for events using select. This works correctly on
+ * Linux with X11 since the events are notified through the file descriptors
+ * where mplayer2 is listening on. On the other hand, the OSX window server
+ * notifies the processes for events using mach ports.
+ *
+ * The code below uses functionality from Cocoa that abstracts the async polling
+ * of events from the window server. When a Cocoa event comes in, the polling is
+ * interrupted and the event is dealt with in the next vo_check_events.
+ *
+ * To keep the select fd polling code working, that functionality is executed
+ * from another thread. Whoever finishes polling before the given time, be it
+ * Cocoa or the original select code, notifies the other for an immediate wake.
+ */
+
+#include "cocoa_events.h"
+#include "libvo/cocoa_common.h"
+#include "talloc.h"
+
+#import <Cocoa/Cocoa.h>
+#include <dispatch/dispatch.h>
+
+// Bogus event subtype to wake the Cocoa code from polling state
+#define MP_EVENT_SUBTYPE_WAKE_EVENTLOOP 100
+
+// This is the threshold in milliseconds below which the Cocoa polling is not
+// executed. There is some overhead caused by the synchronization between
+// threads. Even if in practice it isn't noticeable, we try to avoid the useless
+// waste of resources.
+#define MP_ASYNC_THRESHOLD 50
+
+struct priv {
+    dispatch_queue_t select_queue;
+    bool is_runloop_polling;
+    void (*read_all_fd_events)(struct input_ctx *ictx, int time);
+};
+
+static struct priv *p;
+
+static void cocoa_wait_events(int mssleeptime)
+{
+    NSTimeInterval sleeptime = mssleeptime / 1000.0;
+    NSEvent *event;
+    p->is_runloop_polling = YES;
+    event = [NSApp nextEventMatchingMask:NSAnyEventMask
+           untilDate:[NSDate dateWithTimeIntervalSinceNow:sleeptime]
+           inMode:NSEventTrackingRunLoopMode dequeue:NO];
+
+    // dequeue the next event if it is a fake to wake the cocoa polling
+    if (event && [event type] == NSApplicationDefined &&
+                 [event subtype] == MP_EVENT_SUBTYPE_WAKE_EVENTLOOP) {
+        [NSApp nextEventMatchingMask:NSAnyEventMask untilDate:nil
+               inMode:NSEventTrackingRunLoopMode dequeue:YES];
+    }
+    p->is_runloop_polling = NO;
+}
+
+static void cocoa_wake_runloop()
+{
+    if (p->is_runloop_polling) {
+        NSAutoreleasePool *pool = [NSAutoreleasePool new];
+        NSEvent *event;
+
+        /* Post an event so we'll wake the run loop that is async polling */
+        event = [NSEvent otherEventWithType: NSApplicationDefined
+                                   location: NSZeroPoint
+                              modifierFlags: 0
+                                  timestamp: 0
+                               windowNumber: 0
+                                    context: nil
+                                    subtype: MP_EVENT_SUBTYPE_WAKE_EVENTLOOP
+                                      data1: 0
+                                      data2: 0];
+
+        [NSApp postEvent:event atStart:NO];
+        [pool release];
+    }
+}
+
+void cocoa_events_init(struct input_ctx *ictx,
+    void (*read_all_fd_events)(struct input_ctx *ictx, int time))
+{
+    NSApplicationLoad();
+    p = talloc_ptrtype(NULL, p);
+    *p = (struct priv){
+        .is_runloop_polling = NO,
+        .read_all_fd_events = read_all_fd_events,
+        .select_queue = dispatch_queue_create("org.mplayer2.select_queue",
+                                              NULL),
+    };
+}
+
+void cocoa_events_uninit(void)
+{
+    talloc_free(p);
+}
+
+void cocoa_events_read_all_events(struct input_ctx *ictx, int time)
+{
+    // don't bother delegating the select to the async queue if the blocking
+    // time is really low or if we are not running a GUI
+    if (time > MP_ASYNC_THRESHOLD && vo_cocoa_gui_running()) {
+        dispatch_async(p->select_queue, ^{
+            p->read_all_fd_events(ictx, time);
+            cocoa_wake_runloop();
+        });
+
+        cocoa_wait_events(time);
+        mp_input_wakeup(ictx);
+
+        // wait for the async queue to get empty.
+        dispatch_sync(p->select_queue, ^{});
+    } else {
+        p->read_all_fd_events(ictx, time);
+    }
+}