Start and stop accepting drops

docs/dnd-protocol.rst

@@ -0,0 +1,54 @@
+The Drag and Drop protocol
+==============================================
+
+.. versionadded:: 0.47.0
+
+This protocol enables drag and drop functionality for terminal programs
+that is as good as the drag and drop functionality available for GUI
+programs.
+
+There is one central escape code used for this protocol, which is of the form::
+
+    OSC _dnd_code ; metadata ; base64 encoded payload ST
+
+Here, ``OSC`` is the bytes ``ESC ] (0x1b 0x5b)``. The ``metadata`` is a colon
+separated list of ``key=value`` pairs. The final part of the escape code is the
+:rfc:`base64 <4648>` encoded payload data, whose meaning depends on the
+metadata. The payload must be no more than 4096 bytes *before base64 encoding*.
+
+Accepting drops
+-----------------
+
+In order to inform the terminal emulator that the program accepts drops, it
+must, send the following escape code::
+
+    OSC _dnd_code ; t=a ; payload ST
+
+The payload here is a space separated list of MIME types the program accepts.
+The list of MIME types is optional, it is needed if the program wants to accept
+exotic or private use MIME types on platforms such as macOS, where the system
+does not deliver drop events unless the MIME type is registered.
+
+When the program is done accepting drops, or at exit, it should send the escape
+code::
+
+    OSC _dnd_code ; t=A ST
+
+to inform the terminal that it no longer wants drops.
+
+Metadata reference
+---------------------------
+
+The table below shows all the metadata keys as well as what values they can
+take, and the default value they take when missing. All integers are 32-bit.
+
+=======  ====================  =========  =================
+Key      Value                 Default    Description
+=======  ====================  =========  =================
+``t``    Single character.     ``a``      The overall action this graphics command is performing.
+         ``(a, A,                         ``t`` - transmit data, ``T`` - transmit data and display image,
+         )``                              ``q`` - query terminal, ``p`` - put (display) previous transmitted image,
+                                          ``d`` - delete image, ``f`` - transmit data for animation frames,
+                                          ``a`` - control animation, ``c`` - compose animation frames
+
+

gen/apc_parsers.py

@@ -331,7 +331,7 @@ def parsers() -> None:
     write_header(text, 'kitty/parse-multicell-command.h')
 
     keymap = {
-        't': ('type', flag('ae')),
+        't': ('type', flag('aA')),
         'm': ('more', 'uint'),
     }
     text = generate(

kitty/glfw.c

@@ -765,6 +765,29 @@ read_drop_data(GLFWwindow *window, GLFWDropEvent *ev) {
 #undef finish
 }
 
+void
+register_drop_window(id_type window_id, const uint8_t *payload, size_t payload_sz, bool on) {
+    Window *w = window_for_window_id(window_id);
+    OSWindow *osw = os_window_for_kitty_window(window_id);
+    if (w && osw && osw->handle) {
+        w->accepts_drops = on;
+        if (on && payload && payload_sz) {
+#ifdef __APPLE__
+            RAII_ALLOC(char, copy, malloc(payload_sz + 1)); if (!copy) return;
+            RAII_ALLOC(const char*, mimes, calloc(payload_sz, sizeof(char*))); if (!mimes) return;
+            memcpy(copy, payload, payload_sz); copy[payload_sz] = 0;
+            size_t num = 0;
+            char* token = strtok(copy, " ");
+            while (token != NULL) {
+                mimes[num++] = token;
+                token = strtok(NULL, " ");
+            }
+            glfwCocoaRegisterMIMETypes(osw->handle, mimes, num);
+#endif
+        }
+    }
+}
+
 static void
 on_drop(GLFWwindow *window, GLFWDropEvent *ev) {
     if (!set_callback_window(window)) return;

kitty/screen.c

@@ -1511,11 +1511,8 @@ void
 screen_handle_dnd_command(Screen *self, const DnDCommand *cmd, const uint8_t *payload) {
     if (!self->window_id) return;
     switch(cmd->type) {
-        case 'a':
-            (void)payload;
-            break;
-        case 'e':
-            break;
+        case 'a': register_drop_window(self->window_id, payload, cmd->payload_sz, true); break;
+        case 'A': register_drop_window(self->window_id, NULL, 0, false); break;
     }
 }
 

kitty/screen.h

@@ -323,6 +323,7 @@ bool screen_pause_rendering(Screen *self, bool pause, int for_in_ms);
 void screen_check_pause_rendering(Screen *self, monotonic_t now);
 void screen_designate_charset(Screen *self, uint32_t which, uint32_t as);
 void screen_multi_cursor(Screen *self, int queried_shape, int *params, unsigned num_params);
+void register_drop_window(id_type window_id, const uint8_t *payload, size_t payload_sz, bool on);
 #define DECLARE_CH_SCREEN_HANDLER(name) void screen_##name(Screen *screen);
 DECLARE_CH_SCREEN_HANDLER(bell)
 DECLARE_CH_SCREEN_HANDLER(backspace)

kitty/state.h

@@ -206,7 +206,7 @@ typedef struct WindowBarData {
 
 typedef struct Window {
     id_type id;
-    bool visible;
+    bool visible, accepts_drops;
     PyObject *title;
     WindowRenderData render_data;
     WindowRenderData window_title_render_data;