[vala] GIR parser: add default value to GCancellable arguments when possible

[Evan Nemerson <evann src gnome org>]

commit dccec42432c9fe37729c149b484c6189358299a4
Author: Evan Nemerson <evan coeus-group com>
Date:   Mon Jun 25 13:55:31 2012 -0700

    GIR parser: add default value to GCancellable arguments when possible

 vala/valagirparser.vala |   12 ++++++++++++
 1 files changed, 12 insertions(+), 0 deletions(-)
---
diff --git a/vala/valagirparser.vala b/vala/valagirparser.vala
index 15a5059..cabd1ed 100644
--- a/vala/valagirparser.vala
+++ b/vala/valagirparser.vala
@@ -2872,6 +2872,18 @@ public class Vala.GirParser : CodeVisitor {
 		}
 		current.parameters = parameters;
 
+		for (int param_n = parameters.size - 1 ; param_n >= 0 ; param_n--) {
+			ParameterInfo pi = parameters[param_n];
+			if (pi.param.initializer == null) {
+				string type_string = pi.param.variable_type.to_string ();
+				if (type_string == "Gio.Cancellable?") {
+					pi.param.initializer = new Vala.NullLiteral ();
+				} else {
+					break;
+				}
+			}
+		}
+
 		pop_node ();
 		end_element (element_name);
 	}