gtk2: backport some event handling patches fixing high CPU usage. Fixes

#2407 (#4641)

mingw-w64-gtk2/0020-GDK-W32-Always-process-all-available-messages.patch

@@ -0,0 +1,49 @@
+From bfdac2f70e005b2504cc3f4ebbdab328974d005a Mon Sep 17 00:00:00 2001
+From: Jeremy Tan <jtanx@outlook.com>
+Date: Sat, 17 Sep 2016 17:19:59 +0800
+Subject: [PATCH 06/25] GDK W32: Always process all available messages
+
+The GLib main loop blocks on MsgWaitForMultipleObjectsEx to
+determine if there are any incoming messages while also allowing
+for background tasks to run. If all available messages are not
+processed after MsgWaitForMultipleObjectsEx has signaled that
+there are available, CPU usage will skyrocket.
+
+From my limited understanding (by inspection of profiling
+under Visual Studio):
+Key is pressed - MsgWaitForMultipleObjectsEx unblocks, and
+sends message to GDK's event handler. Some event is now queued.
+
+g_poll unblocks, calls the g_event_dispatch which finally
+resolves to gdk_event_dispatch. This then calls
+_gdk_win32_display_queue_events, but since a message is already
+queued, it fails to call PeekMessage and returns immediately.
+
+At the next iteration, g_poll again calls MsgWaitForMultipleObjectsEx
+which queues yet another event and returns almost immediately, since
+there are events available which haven't been processed by PeekMessage.
+
+The dispatch function is then called and the process repeats.
+
+https://bugzilla.gnome.org/show_bug.cgi?id=771568
+---
+ gdk/win32/gdkevents-win32.c | 3 +--
+ 1 file changed, 1 insertion(+), 2 deletions(-)
+
+diff --git a/gdk/win32/gdkevents-win32.c b/gdk/win32/gdkevents-win32.c
+index 9b09edd052..e52f21c52e 100644
+--- a/gdk/win32/gdkevents-win32.c
++++ b/gdk/win32/gdkevents-win32.c
+@@ -3622,8 +3622,7 @@ _gdk_events_queue (GdkDisplay *display)
+   if (modal_win32_dialog != NULL)
+     return;
+
+-  while (!_gdk_event_queue_find_first (display) &&
+-	 PeekMessageW (&msg, NULL, 0, 0, PM_REMOVE))
++  while (PeekMessageW (&msg, NULL, 0, 0, PM_REMOVE))
+     {
+       TranslateMessage (&msg);
+       DispatchMessageW (&msg);
+-- 
+2.19.1
+

mingw-w64-gtk2/0021-GDK-W32-Ignore-autorepeated-key-presses-on-modifier-.patch

@@ -0,0 +1,36 @@
+From 61162225f712df648f38fd12bc0817cfa9f79a64 Mon Sep 17 00:00:00 2001
+From: Jeremy Tan <jtanx@outlook.com>
+Date: Sat, 17 Sep 2016 20:46:30 +0800
+Subject: [PATCH 07/25] GDK W32: Ignore autorepeated key presses on modifier
+ keys
+
+The X11 backend does not send autorepeated messages for modifier keys,
+and doing so prevents motion compression from working.
+
+https://bugzilla.gnome.org/show_bug.cgi?id=771568
+---
+ gdk/win32/gdkevents-win32.c | 8 ++++++++
+ 1 file changed, 8 insertions(+)
+
+diff --git a/gdk/win32/gdkevents-win32.c b/gdk/win32/gdkevents-win32.c
+index e52f21c52e..ac91fa64cb 100644
+--- a/gdk/win32/gdkevents-win32.c
++++ b/gdk/win32/gdkevents-win32.c
+@@ -2274,6 +2274,14 @@ gdk_event_translate (MSG  *msg,
+ 	  in_ime_composition)
+ 	break;
+
++      /* Ignore autorepeats on modifiers */
++      if (msg->message == WM_KEYDOWN &&
++          (msg->wParam == VK_MENU ||
++           msg->wParam == VK_CONTROL ||
++           msg->wParam == VK_SHIFT) &&
++           ((HIWORD(msg->lParam) & KF_REPEAT) >= 1))
++        break;
++
+       if (!propagate (&window, msg,
+ 		      _gdk_display->keyboard_grab.window,
+ 		      _gdk_display->keyboard_grab.owner_events,
+-- 
+2.19.1
+

mingw-w64-gtk2/PKGBUILD

@@ -5,7 +5,7 @@ _realname=gtk2
 pkgbase=mingw-w64-${_realname}
 pkgname="${MINGW_PACKAGE_PREFIX}-${_realname}"
 pkgver=2.24.32
-pkgrel=2
+pkgrel=3
 pkgdesc="GTK+ is a multi-platform toolkit (v2) (mingw-w64)"
 arch=('any')
 url="https://www.gtk.org/"
@@ -40,7 +40,9 @@ source=("https://download.gnome.org/sources/gtk+/${pkgver%.*}/gtk+-${pkgver}.tar
         0011-gir-for-gdkwin32.mingw.patch
         0012-embed-manifest.all.patch
         0013_fix_mouse_events.patch
-        0019_use_g_stat_and_gstatbuf.patch)
+        0019_use_g_stat_and_gstatbuf.patch
+        0020-GDK-W32-Always-process-all-available-messages.patch
+        0021-GDK-W32-Ignore-autorepeated-key-presses-on-modifier-.patch)
 
 sha256sums=('b6c8a93ddda5eabe3bfee1eb39636c9a03d2a56c7b62828b359bf197943c582e'
             'b77a427df55a14182c10ad7e683b4d662df2846fcd38df2aa8918159d6be3ae2'
@@ -53,7 +55,9 @@ sha256sums=('b6c8a93ddda5eabe3bfee1eb39636c9a03d2a56c7b62828b359bf197943c582e'
             '10569e2bc2afe6ab320dcb4b0e708ddd8235244ec0daff05ca518cb8463f2924'
             '4bc70de68084585dcf2b5a7e4abe32a789360fc2be97a9c94ba3b52dac89ad93'
             'f6d731acecf6e35e4ec9739a6d949d2d045c9396c4564283ee6ec935ec690e24'
-            '2903708fda7b9f306a6a7b7b41518ce7a9ac7b9e622d4a1eed9ce30b945d5971')
+            '2903708fda7b9f306a6a7b7b41518ce7a9ac7b9e622d4a1eed9ce30b945d5971'
+            'f984baf140fa325fab1bbd213d17f9cdcd5138b5ab9d76bd17c2434c4e4b2ac5'
+            '8955a689e9107c175a79766d4dd485941b3974b181e51f40ed2ae6028fd1b170')
 
 prepare() {
   cd gtk+-${pkgver}
@@ -68,6 +72,9 @@ prepare() {
   patch -p1 -i ${srcdir}/0013_fix_mouse_events.patch
   patch -p1 -i ${srcdir}/0019_use_g_stat_and_gstatbuf.patch
 
+  patch -p1 -i ${srcdir}/0020-GDK-W32-Always-process-all-available-messages.patch
+  patch -p1 -i ${srcdir}/0021-GDK-W32-Ignore-autorepeated-key-presses-on-modifier-.patch
+
   autoreconf -fi
   rm "${srcdir}/gtk+-${pkgver}/gtk/gtk.def"
 }