video/out: remove some code duplication between X11 and wayland

Both X11 and Wayland support the same format for drag & drop operations
(text/uri-list), and the code for that was copied from x11_common.c to
wayland_common.c. Factor it out.

input/event.c

@@ -48,3 +48,27 @@ void mp_event_drop_files(struct input_ctx *ictx, int num_files, char **files)
         }
     }
 }
+
+int mp_event_drop_mime_data(struct input_ctx *ictx, const char *mime_type,
+                            bstr data)
+{
+    // X11 and Wayland file list format.
+    if (strcmp(mime_type, "text/uri-list") == 0) {
+        void *tmp = talloc_new(NULL);
+        int num_files = 0;
+        char **files = NULL;
+        while (data.len) {
+            bstr line = bstr_getline(data, &data);
+            line = bstr_strip_linebreaks(line);
+            if (bstr_startswith0(line, "#"))
+                continue;
+            char *s = bstrto0(tmp, line);
+            MP_TARRAY_APPEND(tmp, files, num_files, s);
+        }
+        mp_event_drop_files(ictx, num_files, files);
+        talloc_free(tmp);
+        return num_files > 0;
+    } else {
+        return -1;
+    }
+}

input/event.h

@@ -15,7 +15,14 @@
  * with mpv.  If not, see <http://www.gnu.org/licenses/>.
  */
 
+#include "bstr/bstr.h"
+
 struct input_ctx;
 
 // Enqueue files for playback after drag and drop
 void mp_event_drop_files(struct input_ctx *ictx, int num_files, char **files);
+
+// Drop data in a specific format (identified by the mimetype).
+// Returns <0 on error, ==0 if data was ok but empty, >0 on success.
+int mp_event_drop_mime_data(struct input_ctx *ictx, const char *mime_type,
+                            bstr data);

video/out/wayland_common.c

@@ -734,30 +734,6 @@ static void shedule_resize(struct vo_wayland_state *wl,
     wl->vo->dheight = height;
 }
 
-// stolen from x11 code
-// The data is in the form of the mimetype text/uri-list.
-static bool dnd_handle_drop_data(struct vo *vo, bstr data)
-{
-    void *tmp = talloc_new(NULL);
-    int num_files = 0;
-    char **files = NULL;
-
-    while (data.len) {
-        bstr line = bstr_getline(data, &data);
-        line = bstr_strip_linebreaks(line);
-        if (bstr_startswith0(line, "#"))
-            continue;
-
-        char *s = bstrto0(tmp, line);
-        MP_TARRAY_APPEND(tmp, files, num_files, s);
-
-    }
-    mp_event_drop_files(vo->input_ctx, num_files, files);
-
-    talloc_free(tmp);
-    return num_files > 0;
-}
-
 static bool create_display (struct vo_wayland_state *wl)
 {
     wl->display.display = wl_display_connect(NULL);
@@ -1038,7 +1014,8 @@ static int vo_wayland_check_events (struct vo *vo)
                     if (has_read < to_read) {
                         buffer[str_len] = 0;
                         struct bstr file_list = bstr0(buffer);
-                        dnd_handle_drop_data(wl->vo, file_list);
+                        mp_event_drop_mime_data(vo->input_ctx, "text/uri-list",
+                                                file_list);
                         break;
                     }
                 }

video/out/x11_common.c

@@ -736,25 +736,6 @@ void vo_x11_uninit(struct vo *vo)
     vo->x11 = NULL;
 }
 
-// The data is in the form of the mimetype text/uri-list.
-static bool dnd_handle_drop_data(struct vo *vo, bstr data)
-{
-    void *tmp = talloc_new(NULL);
-    int num_files = 0;
-    char **files = NULL;
-    while (data.len) {
-        bstr line = bstr_getline(data, &data);
-        line = bstr_strip_linebreaks(line);
-        if (bstr_startswith0(line, "#"))
-            continue;
-        char *s = bstrto0(tmp, line);
-        MP_TARRAY_APPEND(tmp, files, num_files, s);
-    }
-    mp_event_drop_files(vo->input_ctx, num_files, files);
-    talloc_free(tmp);
-    return num_files > 0;
-}
-
 static void vo_x11_dnd_init_window(struct vo *vo)
 {
     struct vo_x11_state *x11 = vo->x11;
@@ -860,7 +841,8 @@ static void vo_x11_dnd_handle_selection(struct vo *vo, XSelectionEvent *se)
             if (!bytes_left && type == x11->dnd_requested_format && format == 8)
             {
                 // No idea if this is guaranteed to be \0-padded, so use bstr.
-                success = dnd_handle_drop_data(vo, (bstr){prop, nitems});
+                success = mp_event_drop_mime_data(vo->input_ctx, "text/uri-list",
+                                                  (bstr){prop, nitems}) > 0;
             }
             XFree(prop);
         }