1 files changed, 120 insertions, 0 deletions
diff --git a/dropping.c b/dropping.c
new file mode 100644
index 0000000..412f0ab
--- /dev/null
+++ b/dropping.c
@@ -0,0 +1,120 @@
+/* See LICENSE file for copyright and license details. */
+#include "common.h"
+
+static char url_list_name[] = "text/uri-list";
+static GtkTargetEntry url_list = {url_list_name, 0u, 0u};
+
+static size_t
+get_dropped_files(struct file **files_out, char **uris)
+{
+	GError *error = NULL;
+	char **uri, *path;
+	struct file *dropped_files = NULL;
+	size_t i = 0u;
+
+	if (!uris)
+		goto out;
+
+	for (uri = uris; *uri; uri++)
+		i += 1u;
+	if (!i)
+		goto out;
+	dropped_files = ecalloc(i, sizeof(*dropped_files));
+
+	for (uri = uris, i = 0u; *uri; uri++) {
+		error = NULL; /* g_filename_from_uri requires this initialisation */
+		path = g_filename_from_uri(*uri, NULL, &error);
+		if (!path) {
+			weprintf("g_filename_from_uri: %s", error->message);
+			g_error_free(error);
+			continue;
+		}
+		dropped_files[i++].path = estrdup(path);
+		g_free(path);
+		/* the other fields are set in the next code block */
+	}
+
+out:
+	*files_out = dropped_files;
+	return i;
+}
+
+static void
+drop_files(GtkWidget *widget, GdkDragContext *context, int x, int y,
+           GtkSelectionData *data, unsigned int info, unsigned int time, void *user)
+{
+	char **uris = NULL;
+	struct file *dropped_files;
+	size_t n;
+	int accepted = 1;
+	GdkModifierType modifiers;
+	GdkWindow *event_window;
+
+	(void) x;
+	(void) y;
+	(void) info;
+	(void) user;
+
+	if (gtk_drag_get_source_widget(context) == display_area) {
+		accepted = 0;
+		goto out;
+	}
+	event_window = gtk_widget_get_window(widget);
+	if (!event_window)
+		goto out;
+	if (!gdk_window_get_pointer(event_window, NULL, NULL, &modifiers))
+		goto out;
+
+	uris = gtk_selection_data_get_uris(data);
+	n = get_dropped_files(&dropped_files, uris);
+	if (!n)
+		goto out;
+
+	if ((modifiers & GDK_CONTROL_MASK) && nfiles) {
+		n = files_from_array(dropped_files, n);
+		add_images(dropped_files, n);
+		free(dropped_files);
+	} else {
+		set_images_from_array(dropped_files, n);
+	}
+
+out:
+	gtk_drag_finish(context, accepted, 0, time);
+	if (uris)
+		g_strfreev(uris);
+}
+
+static int
+drop_motion(GtkWidget *widget, GdkDragContext *context, int x, int y, unsigned int time, void *user)
+{
+	GdkWindow *event_window = gtk_widget_get_window(widget);
+	GdkModifierType modifiers;
+	GdkDragAction action = 0;
+
+	(void) x;
+	(void) y;
+	(void) user;
+
+	if (!gtk_get_current_event_state(&modifiers))
+		if (!event_window || !gdk_window_get_pointer(event_window, NULL, NULL, &modifiers))
+			goto out;
+	if (gtk_drag_dest_find_target(widget, context, NULL) == GDK_NONE)
+		goto out;
+
+	action = (modifiers & GDK_CONTROL_MASK) ? GDK_ACTION_COPY : GDK_ACTION_MOVE;
+	if (!(gdk_drag_context_get_actions(context) & action))
+		 action = 0;
+
+out:
+	gdk_drag_status(context, action, time);
+	return 1;
+}
+
+void
+set_up_dropping(void)
+{
+	gtk_drag_dest_set(window, GTK_DEST_DEFAULT_HIGHLIGHT | GTK_DEST_DEFAULT_DROP,
+	                  &url_list, 1u, GDK_ACTION_COPY | GDK_ACTION_MOVE);
+	g_signal_connect(window, "drag-motion", G_CALLBACK(&drop_motion), NULL);
+	g_signal_connect(window, "drag-data-received", G_CALLBACK(&drop_files), NULL);
+}