Allow drop clients to use machine id as well

Author: kovidgoyal

docs/dnd-protocol.rst

@@ -38,7 +38,7 @@ the end of the last chunk.
 Accepting drops
 -----------------
 
-In order to inform the terminal emulator that the program accepts drops, it
+In order to inform the terminal emulator that the client accepts drops, it
 must send the following escape code::
 
     OSC _dnd_code ; t=a ; payload ST
@@ -48,7 +48,17 @@ 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
+The terminal emulator may respond to this escape code with an escape code of
+the form::
+
+    OSC _dnd_code ; t=a ; machine id ST
+
+Here, the :ref:`machine id <machine_id>` is an id that identifies the machine
+the terminal is running on and can be used by the client to determine whether
+to request remote files from the terminal when a drop occurs.
+See :ref:`below <machine_id>` for the semantics of the machine id.
+
+When the client is done accepting drops, or at exit, it should send the escape
 code::
 
     OSC _dnd_code ; t=A ST
@@ -132,8 +142,12 @@ terminal emulator must then inform the OS that the drop is completed.
 Dropping from remote machines
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
-In order to support dropping of files from remote machines,
-clients can first request the :rfc:`text/uri-list <2483>` MIME
+In order to support dropping of files from remote machines, the client
+can use the :ref:`machine id <machine_id>` previously sent by the terminal.
+If it is different from the id of the machine the client is running on, it
+can choose to request remote files, as follows.
+
+Clients can first request the :rfc:`text/uri-list <2483>` MIME
 type to get a list of dropped URIs. For every URI in the list, they can
 send the terminal emulator a data request of the form::
 

kitty/dnd.c

@@ -144,40 +144,6 @@ reset_drop(Window *w) {
     }
 }
 
-void
-drop_register_window(Window *w, const uint8_t *payload, size_t payload_sz, bool on, uint32_t client_id, bool more) {
-    w->drop.wanted = on;
-    w->drop.client_id = client_id;
-    if (!on) { drop_free_data(w); zero_at_ptr(&w->drop); return; }
-    if (!payload || !payload_sz) return;
-    size_t sz = w->drop.registered_mimes ? strlen(w->drop.registered_mimes) : 0;
-    if (sz + payload_sz > MIME_LIST_SIZE_CAP) return;
-    w->drop.registered_mimes = realloc(w->drop.registered_mimes, sz + payload_sz + 1);
-    if (w->drop.registered_mimes) {
-        memcpy(w->drop.registered_mimes + sz, payload, payload_sz);
-        sz += payload_sz;
-        w->drop.registered_mimes[sz] = 0;
-    }
-    if (more) return;
-    if (w->drop.registered_mimes) {
-        OSWindow *osw = os_window_for_kitty_window(w->id);
-        if (osw) {
-            size_t num = 0;
-            RAII_ALLOC(const char*, mimes, malloc(sizeof(char*) * strlen(w->drop.registered_mimes)));
-            if (mimes) {
-                char* token = strtok(w->drop.registered_mimes, " ");
-                while (token != NULL) {
-                    mimes[num++] = token;
-                    token = strtok(NULL, " ");
-                }
-                register_mimes_for_drop(osw, mimes, num);
-            }
-        }
-    }
-    free(w->drop.registered_mimes); w->drop.registered_mimes = NULL;
-}
-
-
 static int
 string_arrays_cmp(const char **a, size_t an, const char **b, size_t bn) {
     if (an != bn) return (int)an - (int)bn;
@@ -289,6 +255,46 @@ queue_payload_to_child(id_type id, uint32_t client_id, PendingData *pending, con
     if (pending->count) check_for_pending_writes();
 }
 
+void
+drop_register_window(Window *w, const uint8_t *payload, size_t payload_sz, bool on, uint32_t client_id, bool more) {
+    w->drop.wanted = on;
+    w->drop.client_id = client_id;
+    if (!on) { drop_free_data(w); zero_at_ptr(&w->drop); return; }
+    if (!payload || !payload_sz) return;
+    size_t sz = w->drop.registered_mimes ? strlen(w->drop.registered_mimes) : 0;
+    if (sz + payload_sz > MIME_LIST_SIZE_CAP) return;
+    w->drop.registered_mimes = realloc(w->drop.registered_mimes, sz + payload_sz + 1);
+    if (w->drop.registered_mimes) {
+        memcpy(w->drop.registered_mimes + sz, payload, payload_sz);
+        sz += payload_sz;
+        w->drop.registered_mimes[sz] = 0;
+    }
+    if (more) return;
+    if (w->drop.registered_mimes) {
+        OSWindow *osw = os_window_for_kitty_window(w->id);
+        if (osw) {
+            size_t num = 0;
+            RAII_ALLOC(const char*, mimes, malloc(sizeof(char*) * strlen(w->drop.registered_mimes)));
+            if (mimes) {
+                char* token = strtok(w->drop.registered_mimes, " ");
+                while (token != NULL) {
+                    mimes[num++] = token;
+                    token = strtok(NULL, " ");
+                }
+                register_mimes_for_drop(osw, mimes, num);
+            }
+        }
+    }
+    free(w->drop.registered_mimes); w->drop.registered_mimes = NULL;
+    const char* host_machine_id = machine_id();
+    if (host_machine_id) {
+        char header[32] = {0};
+        int n = snprintf(header, sizeof(header), "\x1b]%d;t=a", DND_CODE);
+        queue_payload_to_child(
+            w->id, w->drop.client_id, &w->drop.pending, header, n, host_machine_id, strlen(host_machine_id), false);
+    }
+}
+
 void
 drop_move_on_child(Window *w, const char** mimes, size_t num_mimes, bool is_drop) {
     if (!w->drop.hovered) {
@@ -866,13 +872,6 @@ do_drop_request_uri_data(Window *w, int32_t mime_idx, int32_t file_idx) {
     return sync;
 }
 
-void
-drop_request_uri_data(Window *w, const char *payload, size_t payload_sz) {
-    (void)w; (void)payload; (void)payload_sz;
-    /* This function is no longer used in the new protocol; URI data requests
-     * are now handled through the unified t=r queue via do_drop_request_uri_data. */
-}
-
 /* Handle a directory request from the client.
  * handle_id: the directory handle (Y= key).
  * entry_num: 0 means close the handle; >=1 means read that entry (x= key, 1-based).

kitty/dnd.h

@@ -14,7 +14,6 @@ void drop_move_on_child(Window *w, const char **mimes, size_t num_mimes, bool is
 void drop_left_child(Window *w);
 void drop_free_data(Window *w);
 void drop_send_einval(Window *w);
-void drop_request_uri_data(Window *w, const char *payload, size_t payload_sz);
 void drop_handle_dir_request(Window *w, uint32_t handle_id, int32_t entry_num);
 void drop_enqueue_request(Window *w, int32_t cell_x, int32_t cell_y, int32_t pixel_y);
 void drop_set_status(Window *w, int operation, const char *payload, size_t payload_sz, bool more);