Add "document-before-save-as" signal

Right now only the "document-save" is fired when performing "save as"
which lacks the information about the original file name (which, for
instance, is necessary for the LSP client where it needs to notify
the server that the "old" document was closed and the document under
the new name opened).

doc/pluginsignals.c

@@ -92,6 +92,17 @@ signal void (*document_reload)(GObject *obj, GeanyDocument *doc, gpointer user_d
  */
 signal void (*document_before_save)(GObject *obj, GeanyDocument *doc, gpointer user_data);
 
+/** Sent before save as is performed with the original document.
+ *
+ * @param obj a GeanyObject instance, should be ignored.
+ * @param doc the original document. The document with the new file name is still
+ *        reported by the "document-save" signal sent afterwards.
+ * @param user_data user data.
+ *
+ * @since 2.1
+ */
+signal void (*document_before_save_as)(GObject *obj, GeanyDocument *doc, gpointer user_data);
+
 /** Sent when a new document is saved.
  *
  * @param obj a GeanyObject instance, should be ignored.

src/document.c

@@ -1836,6 +1836,8 @@ gboolean document_save_file_as(GeanyDocument *doc, const gchar *utf8_fname)
 
 	g_return_val_if_fail(doc != NULL, FALSE);
 
+	g_signal_emit_by_name(geany_object, "document-before-save-as", doc);
+
 	new_file = document_need_save_as(doc) || (utf8_fname != NULL && strcmp(doc->file_name, utf8_fname) != 0);
 	if (utf8_fname != NULL)
 		SETPTR(doc->file_name, g_strdup(utf8_fname));

src/geanyobject.c

@@ -105,6 +105,13 @@ static void create_signals(GObjectClass *g_object_class)
 		0, NULL, NULL, g_cclosure_marshal_VOID__BOXED,
 		G_TYPE_NONE, 1,
 		GEANY_TYPE_DOCUMENT);
+	geany_object_signals[GCB_DOCUMENT_BEFORE_SAVE_AS] = g_signal_new (
+		"document-before-save-as",
+		G_OBJECT_CLASS_TYPE (g_object_class),
+		G_SIGNAL_RUN_FIRST,
+		0, NULL, NULL, g_cclosure_marshal_VOID__BOXED,
+		G_TYPE_NONE, 1,
+		GEANY_TYPE_DOCUMENT);
 	geany_object_signals[GCB_DOCUMENT_SAVE] = g_signal_new (
 		"document-save",
 		G_OBJECT_CLASS_TYPE (g_object_class),

src/geanyobject.h

@@ -57,6 +57,7 @@ typedef enum
 	GCB_SAVE_SETTINGS,
 	GCB_LOAD_SETTINGS,
 	GCB_KEY_PRESS_NOTIFY,
+	GCB_DOCUMENT_BEFORE_SAVE_AS,
 	GCB_MAX
 }
 GeanyCallbackId;