[vala] GVariant: Fix memory leak when boxing and unboxing variants

[JÃrg Billeter <juergbi src gnome org>]

commit 1b9d1aa6f7abeacb13ac8fa97bb8e7ede453aec1
Author: JÃrg Billeter <j bitron ch>
Date:   Sat Jun 2 17:03:40 2012 +0200

    GVariant: Fix memory leak when boxing and unboxing variants
    
    Fixes bug 674201.

 codegen/valaccodebasemodule.vala |    2 +-
 vala/valacastexpression.vala     |    9 +++++++++
 2 files changed, 10 insertions(+), 1 deletions(-)
---
diff --git a/codegen/valaccodebasemodule.vala b/codegen/valaccodebasemodule.vala
index 0b056e9..f9f9635 100644
--- a/codegen/valaccodebasemodule.vala
+++ b/codegen/valaccodebasemodule.vala
@@ -5324,7 +5324,7 @@ public abstract class Vala.CCodeBaseModule : CodeGenerator {
 		                        && type.data_type != gvariant_type);
 
 		if (type.value_owned
-		    && (target_type == null || !target_type.value_owned || boxing || unboxing)
+		    && (target_type == null || !target_type.value_owned || boxing || unboxing || gvariant_boxing)
 		    && !gvalue_boxing /* gvalue can assume ownership of value, no need to free it */) {
 			// value leaked, destroy it
 			if (target_type is PointerType) {
diff --git a/vala/valacastexpression.vala b/vala/valacastexpression.vala
index 40ed1ce..c7a72b6 100644
--- a/vala/valacastexpression.vala
+++ b/vala/valacastexpression.vala
@@ -152,11 +152,20 @@ public class Vala.CastExpression : Expression {
 			value_type.nullable = true;
 		}
 
+		if (is_gvariant (context, inner.value_type) && !is_gvariant (context, value_type)) {
+			// GVariant unboxing returns owned value
+			value_type.value_owned = true;
+		}
+
 		inner.target_type = inner.value_type.copy ();
 
 		return !error;
 	}
 
+	bool is_gvariant (CodeContext context, DataType type) {
+		return type.data_type != null && type.data_type.is_subtype_of (context.analyzer.gvariant_type.data_type);
+	}
+
 	public override void emit (CodeGenerator codegen) {
 		inner.emit (codegen);