i3 - improved tiling WM

Return DRAG_ABORT on UnmapNotify from drag_pointer

Patch status: needinfo

Patch by Tony Crisci

Long description:

Add DRAG_ABORT to enum drag_result_t. DRAG_ABORT will indicate the drag
operation cannot be completed.

Return DRAG_ABORT on UnmapNotify, or when the keyboard or pointer cannot
be grabbed.

Add DRAGGING to return value for drag_result_t. DRAGGING is used
internally by drag_pointer to indicate the drag is in progress.

Change DRAG_CANCEL to DRAG_REVERT to clarify the distinction between
"abort" and "revert/cancel" actions.

Fixes an issue that caused i3 to crash when a user is dragging or
resizing a floating window that becomes destroyed.

To apply this patch, use:
curl http://cr.i3wm.org/patch/294/raw.patch | git am

b/include/floating.h

29 
@@ -134,12 +134,24 @@ void floating_toggle_hide(xcb_connection_t *conn, Workspace *workspace);
30
31 
 #endif
32 
 /**
33 
- * This is the return value of a drag operation like drag_pointer. DRAG_CANCEL
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- * will indicate the intention of the drag should not be carried out, or that
35 
- * the drag actions should be undone.
36 
+ * This is the return value of a drag operation like drag_pointer.
37 
+ *
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+ * DRAG_SUCCESS will indicate the intention of the drag action should be
39 
+ * carried out.
40 
+ *
41 
+ * DRAG_REVERT will indicate an attempt should be made to restore the state of
42 
+ * the involved windows to their condition before the drag.
43 
+ *
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+ * DRAG_ABORT will indicate that the intention of the drag action cannot be
45 
+ * carried out (e.g. because the window has been unmapped).
46 
  *
47 
  */
48 
-typedef enum { DRAG_SUCCESS = 0, DRAG_CANCEL } drag_result_t;
49 
+typedef enum {
50 
+    DRAGGING = 0,
51 
+    DRAG_SUCCESS,
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+    DRAG_REVERT,
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+    DRAG_ABORT
54 
+} drag_result_t;
55
56 
 /**
57 
  * This function grabs your pointer and keyboard and lets you drag stuff around

b/src/floating.c

62 
@@ -441,14 +441,14 @@ void floating_drag_window(Con *con, const xcb_button_press_event_t *event) {
63 
      * after the user releases the mouse button */
64 
     tree_render();
65
66 
-    /* Store the initial rect in case of user cancel */
67 
+    /* Store the initial rect in case of user revert/cancel */
68 
     Rect initial_rect = con->rect;
69
70 
     /* Drag the window */
71 
     drag_result_t drag_result = drag_pointer(con, event, XCB_NONE, BORDER_TOP /* irrelevant */, XCURSOR_CURSOR_MOVE, drag_window_callback, event);
72
73 
     /* If the user cancelled, undo the changes. */
74 
-    if (drag_result == DRAG_CANCEL)
75 
+    if (drag_result == DRAG_REVERT)
76 
         floating_reposition(con, initial_rect);
77
78 
     /* If this is a scratchpad window, don't auto center it from now on. */
79 
@@ -553,13 +553,13 @@ void floating_resize_window(Con *con, const bool proportional,
80
81 
     struct resize_window_callback_params params = { corner, proportional, event };
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83 
-    /* get the initial rect in case of cancel */
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+    /* get the initial rect in case of revert/cancel */
85 
     Rect initial_rect = con->rect;
86
87 
     drag_result_t drag_result = drag_pointer(con, event, XCB_NONE, BORDER_TOP /* irrelevant */, cursor, resize_window_callback, &params);
88
89 
     /* If the user cancels, undo the resize */
90 
-    if (drag_result == DRAG_CANCEL)
91 
+    if (drag_result == DRAG_REVERT)
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         floating_reposition(con, initial_rect);
93
94 
     /* If this is a scratchpad window, don't auto center it from now on. */
95 
@@ -601,7 +601,7 @@ drag_result_t drag_pointer(Con *con, const xcb_button_press_event_t *event, xcb_
96
97 
     if ((reply = xcb_grab_pointer_reply(conn, cookie, NULL)) == NULL) {
98 
         ELOG("Could not grab pointer\n");
99 
-        return DRAG_CANCEL;
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+        return DRAG_ABORT;
101 
     }
102
103 
     free(reply);
104 
@@ -620,7 +620,7 @@ drag_result_t drag_pointer(Con *con, const xcb_button_press_event_t *event, xcb_
105
106 
     if ((keyb_reply = xcb_grab_keyboard_reply(conn, keyb_cookie, NULL)) == NULL) {
107 
         ELOG("Could not grab keyboard\n");
108 
-        return DRAG_CANCEL;
109 
+        return DRAG_ABORT;
110 
     }
111
112 
     free(keyb_reply);
113 
@@ -629,11 +629,11 @@ drag_result_t drag_pointer(Con *con, const xcb_button_press_event_t *event, xcb_
114 
     xcb_flush(conn);
115
116 
     xcb_generic_event_t *inside_event, *last_motion_notify = NULL;
117 
-    bool loop_done = false;
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-    /* The return value, set to DRAG_CANCEL on user cancel */
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-    drag_result_t drag_result = DRAG_SUCCESS;
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+    Con *inside_con = NULL;
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+    /* The return value, set to exit the event loop */
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+    drag_result_t drag_result = DRAGGING;
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     /* I’ve always wanted to have my own eventhandler… */
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-    while (!loop_done && (inside_event = xcb_wait_for_event(conn))) {
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+    while (drag_result == DRAGGING && (inside_event = xcb_wait_for_event(conn))) {
126 
         /* We now handle all events we can get using xcb_poll_for_event */
127 
         do {
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             /* skip x11 errors */
129 
@@ -646,7 +646,7 @@ drag_result_t drag_pointer(Con *con, const xcb_button_press_event_t *event, xcb_
130
131 
             switch (type) {
132 
                 case XCB_BUTTON_RELEASE:
133 
-                    loop_done = true;
134 
+                    drag_result = DRAG_SUCCESS;
135 
                     break;
136
137 
                 case XCB_MOTION_NOTIFY:
138 
@@ -656,17 +656,18 @@ drag_result_t drag_pointer(Con *con, const xcb_button_press_event_t *event, xcb_
139 
                     break;
140
141 
                 case XCB_UNMAP_NOTIFY:
142 
-                    DLOG("Unmap-notify, aborting\n");
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+                    inside_con = con_by_window_id(((xcb_unmap_notify_event_t*)inside_event)->window);
144 
+
145 
+                    DLOG("UnmapNotify for window 0x%08x (container %p)\n", ((xcb_unmap_notify_event_t*)inside_event)->window, inside_con);
146 
+                    drag_result = DRAG_ABORT;
147 
+
148 
                     handle_event(type, inside_event);
149 
-                    loop_done = true;
150 
-                    drag_result = DRAG_CANCEL;
151 
                     break;
152
153 
                 case XCB_KEY_PRESS:
154 
                     /* Cancel the drag if a key was pressed */
155 
-                    DLOG("A key was pressed during drag, canceling.");
156 
-                    loop_done = true;
157 
-                    drag_result = DRAG_CANCEL;
158 
+                    DLOG("A key was pressed during drag, reverting changes.");
159 
+                    drag_result = DRAG_REVERT;
160
161 
                     handle_event(type, inside_event);
162 
                     break;
163 
@@ -681,7 +682,7 @@ drag_result_t drag_pointer(Con *con, const xcb_button_press_event_t *event, xcb_
164 
                 free(inside_event);
165 
         } while ((inside_event = xcb_poll_for_event(conn)) != NULL);
166
167 
-        if (last_motion_notify == NULL || loop_done)
168 
+        if (last_motion_notify == NULL || drag_result != DRAGGING)
169 
             continue;
170
171 
         new_x = ((xcb_motion_notify_event_t*)last_motion_notify)->root_x;

b/src/resize.c

176 
@@ -161,7 +161,7 @@ int resize_graphical_handler(Con *first, Con *second, orientation_t orientation,
177 
     xcb_flush(conn);
178
179 
     /* User cancelled the drag so no action should be taken. */
180 
-    if (drag_result == DRAG_CANCEL)
181 
+    if (drag_result == DRAG_REVERT)
182 
         return 0;
183
184 
     int pixels;