Implement drop leaving window

docs/dnd-protocol.rst

@@ -63,6 +63,12 @@ list of MIME types that are available for dropping. To avoid overhead, the
 terminal should only send this list for the first move event and subsequently
 only if the list changes.
 
+When the drag leaves the window, the terminal will send the same event but
+with ``x, y = -1, -1`` to indicate that the drag has left the window. For such
+events the list of MIME types must be empty. Note that the terminal must never
+send negative cell co-ordinates for any other reason.
+
+
 Metadata reference
 ---------------------------
 
@@ -85,8 +91,8 @@ Key      Value                 Default    Description
                                           have it set to the same value.
 **Keys for location**
 -----------------------------------------------------------
-``x``    Positive integer      ``0``      Cell x-coordinate origin is 0, 0 at top left of screen
-``y``    Positive integer      ``0``      Cell y-coordinate origin is 0, 0 at top left of screen
+``x``    Integer               ``0``      Cell x-coordinate origin is 0, 0 at top left of screen
+``y``    Integer               ``0``      Cell y-coordinate origin is 0, 0 at top left of screen
 ``X``    Integer               ``0``      Pixel x-coordinate origin is 0, 0 at top left of screen
 ``Y``    Integer               ``0``      Pixel y-coordinate origin is 0, 0 at top left of screen
 =======  ====================  =========  =================

kitty/dnd.c

@@ -44,11 +44,18 @@ string_arrays_cmp(const char **a, size_t an, const char **b, size_t bn) {
 }
 
 static size_t
-send_payload_to_child(id_type id, const char *header, size_t header_sz, const char *data, size_t data_sz) {
+send_payload_to_child(id_type id, const char *header, size_t header_sz, const char *data, const size_t data_sz) {
     size_t offset = 0;
     char buf[4096 + 1024];
     memcpy(buf, header, header_sz);
     buf[header_sz++] = ':'; buf[header_sz++] = 'm'; buf[header_sz++] = '=';
+    if (!data_sz) {
+        buf[header_sz++] = 0x1b; buf[header_sz++] = '\\';
+        bool found, too_much_data;
+        schedule_write_to_child_if_possible(id, buf, header_sz, &found, &too_much_data);
+        if (too_much_data) return 0;
+        return 1;
+    }
     while (offset < data_sz) {
         size_t chunk = data_sz - offset;
         size_t p = header_sz;
@@ -79,7 +86,8 @@ flush_pending(id_type id, PendingData *pending) {
             }
             break;
         } else {
-            free(e->buf);
+            if (!e->data_sz && !written) break;
+            free(e->buf); zero_at_ptr(e);
             remove_i_from_array(pending->items, 0, pending->count);
         }
     }
@@ -90,7 +98,7 @@ static void
 queue_payload_to_child(id_type id, PendingData *pending, const char *header, size_t header_sz, const char *data, size_t data_sz) {
     size_t offset = 0;
     if (flush_pending(id, pending)) offset = send_payload_to_child(id, header, header_sz, data, data_sz);
-    if (offset < data_sz) {
+    if (offset < data_sz || (!offset && !data_sz)) {
         ensure_space_for(pending, items, PendingEntry, pending->count + 1, capacity, 32, true);
         char *buf = malloc(header_sz + data_sz - offset);
         if (!buf) fatal("Out of memory");
@@ -145,3 +153,14 @@ drop_move_on_child(Window *w, const char** mimes, size_t num_mimes) {
         schedule_write_to_child_if_possible(w->id, buf, header_size, &found, &too_much_data);
     }
 }
+
+void
+drop_left_child(Window *w) {
+    w->drop.hovered = false;
+    drop_free_offered_mimes(w);
+    if (w->drop.allowed) {
+        char buf[128];
+        int header_size = snprintf(buf, sizeof(buf), "\x1b]%d;i=%u:t=m:x=-1:y=-1", DND_CODE, w->drop.client_id);
+        queue_payload_to_child(w->id, &w->drop.pending, buf, header_size, NULL, 0);
+    }
+}

kitty/dnd.h

@@ -9,4 +9,5 @@
 #include "state.h"
 
 void drop_move_on_child(Window *w, const char **mimes, size_t num_mimes);
+void drop_left_child(Window *w);
 void drop_free_data(Window *w);

kitty/glfw.c

@@ -796,13 +796,17 @@ on_drop(GLFWwindow *window, GLFWDropEvent *ev) {
     if (!set_callback_window(window)) return;
     OSWindow *os_window = global_state.callback_os_window;
     Window *w = NULL;
+    bool is_kitty_ui_drag = false;
+    for (size_t i = 0; i < ev->num_mimes; i++) {
+        if (is_droppable_mime(ev->mimes[i]) >= TAB_DRAG_MIME_NUMBER) { is_kitty_ui_drag = true; break;}
+    }
     switch (ev->type) {
         case GLFW_DROP_ENTER:
         case GLFW_DROP_MOVE:
             os_window->last_drag_event.x = (int)(ev->xpos * os_window->viewport_x_ratio);
             os_window->last_drag_event.y = (int)(ev->ypos * os_window->viewport_y_ratio);
             on_mouse_position_update(ev->xpos, ev->ypos);
-            if (global_state.mouse_hover_in_window && (w = window_for_window_id(global_state.mouse_hover_in_window)) && w->drop.allowed) {
+            if (!is_kitty_ui_drag && global_state.mouse_hover_in_window && (w = window_for_window_id(global_state.mouse_hover_in_window)) && w->drop.allowed) {
                 drop_move_on_child(w, ev->mimes, ev->num_mimes);
                 return;
             }
@@ -811,9 +815,18 @@ on_drop(GLFWwindow *window, GLFWDropEvent *ev) {
                 ev->from_self ? Py_True : Py_False, Py_False);
             /* fallthrough */
         case GLFW_DROP_STATUS_UPDATE:
-            update_allowed_mimes_for_drop(ev);
+            if (is_kitty_ui_drag) update_allowed_mimes_for_drop(ev);
+            else {
+            }
             break;
         case GLFW_DROP_LEAVE:
+            for (size_t tc = 0; tc < os_window->num_tabs; tc++) {
+                Tab *t = os_window->tabs + tc;
+                for (size_t i = 0; i < t->num_windows; i++) {
+                    Window *w = t->windows + i;
+                    if (w->drop.hovered) drop_left_child(w);
+                }
+            }
             call_boss(on_drop_move, "KiiOO",
                 os_window->id, os_window->last_drag_event.x, os_window->last_drag_event.y,
                 ev->from_self ? Py_True : Py_False, Py_True);

kitty/mouse.c

@@ -8,6 +8,7 @@
 #include "state.h"
 #include "screen.h"
 #include "charsets.h"
+#include "dnd.h"
 #include <limits.h>
 #include <math.h>
 #include "glfw-wrapper.h"
@@ -179,6 +180,7 @@ set_currently_hovered_window(id_type window_id, int modifiers) {
         if (left_window) {
             if (left_window->scrollbar.is_hovering) update_scrollbar_hover_state(left_window, false);
             if (left_window->render_data.screen) screen_mark_url(left_window->render_data.screen, 0, 0, 0, 0);
+            if (left_window->drop.hovered) drop_left_child(left_window);
             int sz = encode_mouse_event(left_window, 0, LEAVE, modifiers);
             if (sz > 0) {
                 mouse_event_buf[sz] = 0;

kitty/state.h

@@ -180,7 +180,7 @@ typedef struct ClickQueue {
 } ClickQueue;
 
 typedef struct MousePosition {
-    unsigned int cell_x, cell_y;
+    unsigned cell_x, cell_y;
     double global_x, global_y;
     bool in_left_half_of_cell;
 } MousePosition;