i3 - improved tiling WM

Improve drag_pointer error handling

Patch status: merged

Patch by Tony Crisci

Long description:

Log errors generated by failed pointer grabs and ungrab the pointer
after failed keyboard grabs.

To apply this patch, use:
curl http://cr.i3wm.org/patch/422/raw.patch | git am

b/src/floating.c

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@@ -682,6 +682,8 @@ drag_result_t drag_pointer(Con *con, const xcb_button_press_event_t *event, xcb_
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     /* Grab the pointer */
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     xcb_grab_pointer_cookie_t cookie;
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     xcb_grab_pointer_reply_t *reply;
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+    xcb_generic_error_t *error;
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+
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     cookie = xcb_grab_pointer(conn,
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         false,               /* get all pointer events specified by the following mask */
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         root,                /* grab the root window */
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@@ -692,8 +694,9 @@ drag_result_t drag_pointer(Con *con, const xcb_button_press_event_t *event, xcb_
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         xcursor,             /* possibly display a special cursor */
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         XCB_CURRENT_TIME);
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-    if ((reply = xcb_grab_pointer_reply(conn, cookie, NULL)) == NULL) {
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-        ELOG("Could not grab pointer\n");
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+    if ((reply = xcb_grab_pointer_reply(conn, cookie, &error)) == NULL) {
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+        ELOG("Could not grab pointer (error_code = %d)\n", error->error_code);
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+        free(error);
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         return DRAG_ABORT;
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     }
35
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@@ -711,8 +714,10 @@ drag_result_t drag_pointer(Con *con, const xcb_button_press_event_t *event, xcb_
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             XCB_GRAB_MODE_ASYNC /* keyboard mode */
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             );
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-    if ((keyb_reply = xcb_grab_keyboard_reply(conn, keyb_cookie, NULL)) == NULL) {
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-        ELOG("Could not grab keyboard\n");
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+    if ((keyb_reply = xcb_grab_keyboard_reply(conn, keyb_cookie, &error)) == NULL) {
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+        ELOG("Could not grab keyboard (error_code = %d)\n", error->error_code);
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+        free(error);
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+        xcb_ungrab_pointer(conn, XCB_CURRENT_TIME);
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         return DRAG_ABORT;
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     }
48