From 3dc782adc709644a5fe4b94f427c24757989023b Mon Sep 17 00:00:00 2001
From: Rico Tzschichholz <ricotz@ubuntu.com>
Date: Thu, 22 Oct 2020 11:02:57 +0200
Subject: gtkmodule: Support "binding" to bind GtkCallback to class of given
 property

Fixes https://gitlab.gnome.org/GNOME/vala/issues/1093
---
 codegen/valagtkmodule.vala         | 46 ++++++++++++++++++++++++++++++++++++--
 tests/gtktemplate/gtktemplate.ui   | 11 +++++++++
 tests/gtktemplate/gtktemplate.vala |  7 ++++++
 3 files changed, 62 insertions(+), 2 deletions(-)

diff --git a/codegen/valagtkmodule.vala b/codegen/valagtkmodule.vala
index 2f3431653..f78b39203 100644
--- a/codegen/valagtkmodule.vala
+++ b/codegen/valagtkmodule.vala
@@ -30,6 +30,8 @@ public class Vala.GtkModule : GSignalModule {
 	/* GResource name to real file name mapping */
 	private HashMap<string, string> gresource_to_file_map = null;
 	/* GtkBuilder xml handler to Vala signal mapping */
+	private HashMap<string, Property> current_handler_to_property_map = new HashMap<string, Property>(str_hash, str_equal);
+	/* GtkBuilder xml handler to Vala signal mapping */
 	private HashMap<string, Signal> current_handler_to_signal_map = new HashMap<string, Signal>(str_hash, str_equal);
 	/* GtkBuilder xml child to Vala class mapping */
 	private HashMap<string, Class> current_child_to_class_map = new HashMap<string, Class>(str_hash, str_equal);
@@ -145,6 +147,7 @@ public class Vala.GtkModule : GSignalModule {
 
 		MarkupReader reader = new MarkupReader (ui_file);
 		Class current_class = null;
+		Property? current_property = null;
 
 		bool template_tag_found = false;
 		MarkupTokenType current_token = reader.read_token (null, null);
@@ -199,6 +202,35 @@ public class Vala.GtkModule : GSignalModule {
 						current_handler_to_signal_map.set (handler_name, sig);
 					}
 				}
+			} else if (current_class != null && current_token == MarkupTokenType.START_ELEMENT && current_name == "binding") {
+				var property_name = reader.get_attribute ("name");
+				if (property_name == null) {
+					Report.error (node.source_reference, "Invalid binding in ui file `%s'".printf (ui_file));
+					current_token = reader.read_token (null, null);
+					continue;
+				}
+
+				property_name = property_name.replace ("-", "_");
+				current_property = SemanticAnalyzer.symbol_lookup_inherited (current_class, property_name) as Property;
+				if (current_property == null) {
+					Report.error (node.source_reference, "Unknown property `%s:%s' for binding in ui file `%s'".printf (current_class.get_full_name (), property_name, ui_file));
+					current_token = reader.read_token (null, null);
+					continue;
+				}
+			} else if (current_class != null && current_token == MarkupTokenType.START_ELEMENT && current_name == "closure") {
+				var handler_name = reader.get_attribute ("function");
+
+				if (current_property != null) {
+					if (handler_name == null) {
+						Report.error (node.source_reference, "Invalid closure in ui file `%s'".printf (ui_file));
+						current_token = reader.read_token (null, null);
+						continue;
+					}
+
+					//TODO Retrieve signature declaration? c-type to vala-type?
+					current_handler_to_property_map.set (handler_name, current_property);
+					current_property = null;
+				}
 			}
 			current_token = reader.read_token (null, null);
 		}
@@ -337,8 +369,9 @@ public class Vala.GtkModule : GSignalModule {
 		/* Handler name as defined in the gtkbuilder xml */
 		var handler_name = m.get_attribute_string ("GtkCallback", "name", m.name);
 		var sig = current_handler_to_signal_map.get (handler_name);
-		if (sig == null) {
-			Report.error (m.source_reference, "could not find signal for handler `%s'".printf (handler_name));
+		var prop = current_handler_to_property_map.get (handler_name);
+		if (sig == null && prop == null) {
+			Report.error (m.source_reference, "could not find signal or property for handler `%s'".printf (handler_name));
 			return;
 		}
 
@@ -361,6 +394,15 @@ public class Vala.GtkModule : GSignalModule {
 				ccode.add_expression (call);
 			}
 		}
+		if (prop != null) {
+			prop.check (context);
+			//TODO Perform signature check
+			var call = new CCodeFunctionCall (new CCodeIdentifier ("gtk_widget_class_bind_template_callback_full"));
+			call.add_argument (new CCodeIdentifier ("GTK_WIDGET_CLASS (klass)"));
+			call.add_argument (new CCodeConstant ("\"%s\"".printf (handler_name)));
+			call.add_argument (new CCodeIdentifier ("G_CALLBACK(%s)".printf (get_ccode_name (m))));
+			ccode.add_expression (call);
+		}
 
 		pop_context ();
 	}
diff --git a/tests/gtktemplate/gtktemplate.ui b/tests/gtktemplate/gtktemplate.ui
index 1546d9472..df9ca019d 100644
--- a/tests/gtktemplate/gtktemplate.ui
+++ b/tests/gtktemplate/gtktemplate.ui
@@ -42,6 +42,17 @@
             <property name="position">1</property>
           </packing>
         </child>
+        <child>
+          <object class="GtkLabel" id="label0">
+            <binding name="label">
+              <closure type="gchararray" function="on_enabled_cb">
+                <constant type="gchararray">some string</constant>
+                <constant type="gint">42</constant>
+                <lookup name="boolean0">GtkTemplateTest</lookup>
+              </closure>
+            </binding>
+          </object>
+        </child>
       </object>
     </child>
   </template>
diff --git a/tests/gtktemplate/gtktemplate.vala b/tests/gtktemplate/gtktemplate.vala
index fa6317ff0..5f66ccc21 100644
--- a/tests/gtktemplate/gtktemplate.vala
+++ b/tests/gtktemplate/gtktemplate.vala
@@ -6,6 +6,8 @@ public class GtkTemplate : Gtk.ApplicationWindow {
 	[GtkChild (internal = true)]
 	public Gtk.Button button1;
 
+	public bool boolean0 { get; set; }
+
 	[GtkCallback]
 	void on_clicked_cb (Gtk.Button button) {
 	}
@@ -13,4 +15,9 @@ public class GtkTemplate : Gtk.ApplicationWindow {
 	[GtkCallback (name = "on_activate_cb")]
 	void on_something_cb (Gtk.Button button) {
 	}
+
+	[GtkCallback]
+	string on_enabled_cb (string s, int i, bool val) {
+		return "%s:%i".printf (s, i);
+	}
 }
-- 
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