fe-gtk: make image drag-and-drop upload work on Windows

src/fe-gtk/hex-input-edit.c

@@ -162,6 +162,7 @@ enum {
 	SIGNAL_ACTIVATE,
 	SIGNAL_WORD_CHECK,
 	SIGNAL_IMAGE_PASTE,
+	SIGNAL_FILE_PASTE,
 	LAST_SIGNAL
 };
 
@@ -1101,6 +1102,36 @@ paste_texture_ready_cb (GObject *source, GAsyncResult *result, gpointer data)
 	g_object_unref (edit);
 }
 
+/* Async file-list paste callback: offer the copied files to the embedder via
+ * "file-paste" (which uploads any images).  If the embedder doesn't handle
+ * them (no images among them), fall back to pasting the clipboard as text so
+ * e.g. a copied file's path still pastes where the source app offers one. */
+static void
+paste_file_list_ready_cb (GObject *source, GAsyncResult *result, gpointer data)
+{
+	HexInputEdit *edit = HEX_INPUT_EDIT (data);
+	GdkClipboard *clip = GDK_CLIPBOARD (source);
+	const GValue *value = gdk_clipboard_read_value_finish (clip, result, NULL);
+	gboolean handled = FALSE;
+
+	if (value && G_VALUE_HOLDS (value, GDK_TYPE_FILE_LIST))
+	{
+		GdkFileList *files = g_value_get_boxed (value);
+		if (files)
+			g_signal_emit (edit, signals[SIGNAL_FILE_PASTE], 0, files,
+			               &handled);
+	}
+
+	if (!handled)
+	{
+		/* transfers our ref on `edit` to the text callback */
+		gdk_clipboard_read_text_async (clip, NULL,
+		                               paste_text_ready_cb, edit);
+		return;
+	}
+	g_object_unref (edit);
+}
+
 static void
 do_paste (HexInputEdit *edit, GdkClipboard *clip)
 {
@@ -1117,6 +1148,20 @@ do_paste (HexInputEdit *edit, GdkClipboard *clip)
 		return;
 	}
 
+	/* Copied files (Explorer Ctrl+C arrives as CFSTR_SHELLIDLIST, which GDK
+	 * advertises as text/uri-list and deserializes to a GdkFileList; Linux
+	 * file managers offer text/uri-list directly).  Offer them to the
+	 * embedder; it falls back to text if none are images. */
+	if (prefs.hex_url_image_upload_enable && formats &&
+	    gdk_content_formats_contain_gtype (formats, GDK_TYPE_FILE_LIST))
+	{
+		g_object_ref (edit);
+		gdk_clipboard_read_value_async (clip, GDK_TYPE_FILE_LIST,
+		                                G_PRIORITY_DEFAULT, NULL,
+		                                paste_file_list_ready_cb, edit);
+		return;
+	}
+
 	g_object_ref (edit);
 	gdk_clipboard_read_text_async (clip, NULL,
 	                               paste_text_ready_cb, edit);
@@ -2770,6 +2815,18 @@ hex_input_edit_class_init (HexInputEditClass *klass)
 		NULL, NULL,
 		g_cclosure_marshal_generic,
 		G_TYPE_NONE, 1, G_TYPE_BYTES);
+
+	/* Emitted when the user pastes copied files; the argument is a
+	 * GdkFileList.  Return TRUE if handled (an upload started) — otherwise
+	 * the widget falls back to pasting the clipboard as text. */
+	signals[SIGNAL_FILE_PASTE] = g_signal_new (
+		"file-paste",
+		G_TYPE_FROM_CLASS (klass),
+		G_SIGNAL_RUN_LAST,
+		G_STRUCT_OFFSET (HexInputEditClass, file_paste),
+		g_signal_accumulator_true_handled, NULL,
+		g_cclosure_marshal_generic,
+		G_TYPE_BOOLEAN, 1, GDK_TYPE_FILE_LIST);
 }
 
 /* =============================== */

src/fe-gtk/hex-input-edit.h

@@ -55,6 +55,7 @@ struct _HexInputEditClass
 	void     (*activate)    (HexInputEdit *edit);
 	gboolean (*word_check)  (HexInputEdit *edit, const char *word);
 	void     (*image_paste) (HexInputEdit *edit, GBytes *png_bytes);
+	gboolean (*file_paste)  (HexInputEdit *edit, GdkFileList *files);
 };
 
 GType      hex_input_edit_get_type     (void) G_GNUC_CONST;

src/fe-gtk/maingui.c

@@ -4732,6 +4732,108 @@ mg_input_image_paste (HexInputEdit *entry, GBytes *png_bytes, gpointer user_data
 	mg_upload_image (current_sess, png_bytes, "pasted.png");
 }
 
+/* Is `file` an image?  Checks the GIO content type's MIME form, then falls
+ * back to the extension.  The MIME conversion matters on Windows: Win32 GIO
+ * content types are registry extension strings (".png", not "image/png"),
+ * so a bare "image/" prefix test on the raw type never matches there, and
+ * the registry frequently has no "Content Type" for newer formats (.webp),
+ * hence the extension fallback. */
+static gboolean
+mg_file_is_image (GFile *file)
+{
+	static const char *const image_exts[] = {
+		".png", ".jpg", ".jpeg", ".gif", ".webp", ".bmp", ".svg",
+		".avif", ".heic", ".heif", ".tif", ".tiff", ".ico"
+	};
+	GFileInfo *info;
+	gboolean is_image = FALSE;
+	char *basename;
+	gsize i;
+
+	info = g_file_query_info (file, G_FILE_ATTRIBUTE_STANDARD_CONTENT_TYPE,
+	                          G_FILE_QUERY_INFO_NONE, NULL, NULL);
+	if (info)
+	{
+		const char *ct = g_file_info_get_content_type (info);
+		if (ct)
+		{
+			char *mime = g_content_type_get_mime_type (ct);
+			if ((mime && g_str_has_prefix (mime, "image/")) ||
+			    g_str_has_prefix (ct, "image/"))
+				is_image = TRUE;
+			g_free (mime);
+		}
+		g_object_unref (info);
+	}
+	if (is_image)
+		return TRUE;
+
+	basename = g_file_get_basename (file);
+	if (basename)
+	{
+		const char *dot = strrchr (basename, '.');
+		if (dot)
+			for (i = 0; i < G_N_ELEMENTS (image_exts); i++)
+				if (g_ascii_strcasecmp (dot, image_exts[i]) == 0)
+				{
+					is_image = TRUE;
+					break;
+				}
+		g_free (basename);
+	}
+	return is_image;
+}
+
+/* Upload one dropped file if it's an image.  Returns FALSE (without side
+ * effects) for non-images so the caller can leave the drop unhandled. */
+static gboolean
+mg_input_upload_image_file (GFile *file)
+{
+	char *contents = NULL, *basename;
+	gsize len = 0;
+	GBytes *bytes;
+
+	if (!file || !mg_file_is_image (file))
+		return FALSE;
+
+	if (!g_file_load_contents (file, NULL, &contents, &len, NULL, NULL))
+		return FALSE;
+	if (len == 0 || len > IMAGE_UPLOAD_MAX_SIZE)
+	{
+		g_free (contents);
+		return FALSE;
+	}
+
+	basename = g_file_get_basename (file);
+	bytes = g_bytes_new_take (contents, len);	/* takes ownership */
+	mg_upload_image (current_sess, bytes, basename);
+	g_bytes_unref (bytes);
+	g_free (basename);
+	return TRUE;
+}
+
+/* "file-paste" from the input widget: files were pasted (e.g. Explorer /
+ * file-manager Ctrl+C on image files).  Upload any images; returning FALSE
+ * when none are lets the widget fall back to a text paste. */
+static gboolean
+mg_input_file_paste (HexInputEdit *entry, GdkFileList *files, gpointer user_data)
+{
+	GSList *list, *l;
+	gboolean any = FALSE;
+
+	(void) entry; (void) user_data;
+
+	if (!prefs.hex_url_image_upload_enable)
+		return FALSE;
+
+	list = gdk_file_list_get_files (files);
+	for (l = list; l; l = l->next)
+		if (mg_input_upload_image_file (l->data))
+			any = TRUE;
+	g_slist_free (list);
+	return any;
+}
+
 /* Drop target on the input box: upload dropped image textures and image files;
  * let everything else fall through to default handling. */
 static gboolean
@@ -4758,46 +4860,25 @@ mg_input_image_drop_cb (GtkDropTarget *target, const GValue *value,
 		return TRUE;
 	}
 
-	if (G_VALUE_HOLDS (value, G_TYPE_FILE))
+	/* Windows shell drags (CF_HDROP) arrive as a GdkFileList — a target
+	 * typed only G_TYPE_FILE never matches the offer, so Explorer drags
+	 * saw no drop target at all (same gap as the DCC targets had). */
+	if (G_VALUE_HOLDS (value, GDK_TYPE_FILE_LIST))
 	{
-		GFile *file = g_value_get_object (value);
-		GFileInfo *info;
-		char *contents = NULL, *basename;
-		gsize len = 0;
-		gboolean is_image = FALSE;
-		GBytes *bytes;
-
-		if (!file)
-			return FALSE;
-
-		info = g_file_query_info (file, G_FILE_ATTRIBUTE_STANDARD_CONTENT_TYPE,
-		                          G_FILE_QUERY_INFO_NONE, NULL, NULL);
-		if (info)
-		{
-			const char *ct = g_file_info_get_content_type (info);
-			if (ct && g_str_has_prefix (ct, "image/"))
-				is_image = TRUE;
-			g_object_unref (info);
-		}
-		if (!is_image)
-			return FALSE;	/* not an image — leave to existing behavior */
-
-		if (!g_file_load_contents (file, NULL, &contents, &len, NULL, NULL))
-			return FALSE;
-		if (len == 0 || len > IMAGE_UPLOAD_MAX_SIZE)
-		{
-			g_free (contents);
-			return FALSE;
-		}
+		GSList *files = gdk_file_list_get_files (g_value_get_boxed (value));
+		GSList *l;
+		gboolean any = FALSE;
 
-		basename = g_file_get_basename (file);
-		bytes = g_bytes_new_take (contents, len);	/* takes ownership */
-		mg_upload_image (current_sess, bytes, basename);
-		g_bytes_unref (bytes);
-		g_free (basename);
-		return TRUE;
+		for (l = files; l; l = l->next)
+			if (mg_input_upload_image_file (l->data))
+				any = TRUE;
+		g_slist_free (files);
+		return any;
 	}
 
+	if (G_VALUE_HOLDS (value, G_TYPE_FILE))
+		return mg_input_upload_image_file (g_value_get_object (value));
+
 	return FALSE;
 }
 
@@ -4892,7 +4973,7 @@ mg_create_entry (session *sess, GtkWidget *box)
 	 * "image-paste" signal below. */
 	{
 		GtkDropTarget *drop;
-		GType drop_types[] = { GDK_TYPE_TEXTURE, G_TYPE_FILE };
+		GType drop_types[] = { GDK_TYPE_TEXTURE, GDK_TYPE_FILE_LIST, G_TYPE_FILE };
 
 		drop = gtk_drop_target_new (G_TYPE_INVALID, GDK_ACTION_COPY);
 		gtk_drop_target_set_gtypes (drop, drop_types, G_N_ELEMENTS (drop_types));
@@ -4901,6 +4982,8 @@ mg_create_entry (session *sess, GtkWidget *box)
 	}
 	g_signal_connect (entry, "image-paste",
 	                  G_CALLBACK (mg_input_image_paste), NULL);
+	g_signal_connect (entry, "file-paste",
+	                  G_CALLBACK (mg_input_file_paste), NULL);
 
 	/* Share xtext's emoji cache and palette with the input box */
 	if (gui->xtext && GTK_XTEXT (gui->xtext)->emoji_cache)