codegen: Add default_value for CType to initialize variables if needed

Fixes https://gitlab.gnome.org/GNOME/vala/issues/724

4 files changed, 14 insertions, 6 deletions

diff --git a/codegen/valaccodebasemodule.vala b/codegen/valaccodebasemodule.vala
index 6662e1c45..d63c4ae52 100644
--- a/codegen/valaccodebasemodule.vala
+++ b/codegen/valaccodebasemodule.vala
@@ -6360,6 +6360,8 @@ public abstract class Vala.CCodeBaseModule : CodeGenerator {
 			return new CCodeConstant ("NULL");
 		} else if (type is ErrorType) {
 			return new CCodeConstant ("NULL");
+		} else if (type is CType) {
+			return new CCodeConstant (((CType) type).cdefault_value);
 		}
 		return null;
 	}
diff --git a/codegen/valaccodemethodcallmodule.vala b/codegen/valaccodemethodcallmodule.vala
index d69df60cc..a2628a783 100644
--- a/codegen/valaccodemethodcallmodule.vala
+++ b/codegen/valaccodemethodcallmodule.vala
@@ -432,7 +432,7 @@ public class Vala.CCodeMethodCallModule : CCodeAssignmentModule {
 							var array_type = (ArrayType) param.variable_type;
 							var length_ctype = get_ccode_array_length_type (param) ?? get_ccode_array_length_type (array_type);
 							for (int dim = 1; dim <= array_type.rank; dim++) {
-								var temp_array_length = get_temp_variable (new CType (length_ctype));
+								var temp_array_length = get_temp_variable (new CType (length_ctype, "0"), true, null, true);
 								emit_temp_var (temp_array_length);
 								append_array_length (arg, get_variable_cexpression (temp_array_length.name));
 								carg_map.set (get_param_pos (get_ccode_array_length_pos (param) + 0.01 * dim), new CCodeUnaryExpression (CCodeUnaryOperator.ADDRESS_OF, get_array_lengths (arg).get (dim - 1)));
@@ -519,7 +519,7 @@ public class Vala.CCodeMethodCallModule : CCodeAssignmentModule {
 					append_array_length (expr, len_call);
 				} else if (get_ccode_array_length (m)) {
 					var length_ctype = get_ccode_array_length_type (m) ?? get_ccode_array_length_type (array_type);
-					var temp_var = get_temp_variable (new CType (length_ctype), true, null, true);
+					var temp_var = get_temp_variable (new CType (length_ctype, "0"), true, null, true);
 					var temp_ref = get_variable_cexpression (temp_var.name);
 
 					emit_temp_var (temp_var);
@@ -582,7 +582,7 @@ public class Vala.CCodeMethodCallModule : CCodeAssignmentModule {
 
 					append_array_length (expr, len_call);
 				} else if (get_ccode_array_length (deleg)) {
-					var temp_var = get_temp_variable (new CType (get_ccode_array_length_type (array_type)), true, null, true);
+					var temp_var = get_temp_variable (array_type.length_type, true, null, true);
 					var temp_ref = get_variable_cexpression (temp_var.name);
 
 					emit_temp_var (temp_var);
diff --git a/codegen/valactype.vala b/codegen/valactype.vala
index 1190299cb..88894069e 100644
--- a/codegen/valactype.vala
+++ b/codegen/valactype.vala
@@ -29,11 +29,17 @@ public class Vala.CType : DataType {
 	 */
 	public string ctype_name { get; set; }
 
-	public CType (string ctype_name) {
+	/**
+	 * The default value of the C type.
+	 */
+	public string cdefault_value { get; set; }
+
+	public CType (string ctype_name, string cdefault_value) {
 		this.ctype_name = ctype_name;
+		this.cdefault_value = cdefault_value;
 	}
 
 	public override DataType copy () {
-		return new CType (ctype_name);
+		return new CType (ctype_name, cdefault_value);
 	}
 }
diff --git a/codegen/valagtypemodule.vala b/codegen/valagtypemodule.vala
index 3dd0f2c48..017ac6a34 100644
--- a/codegen/valagtypemodule.vala
+++ b/codegen/valagtypemodule.vala
@@ -2380,7 +2380,7 @@ public class Vala.GTypeModule : GErrorModule {
 			expr.value_type.value_owned = true;
 			set_cvalue (expr, to_string);
 		} else {
-			var temp_var = get_temp_variable (new CType (is_flags ? "GFlagsValue*" : "GEnumValue*"), false, expr, false);
+			var temp_var = get_temp_variable (new CType (is_flags ? "GFlagsValue*" : "GEnumValue*", "NULL"), false, expr, false);
 			emit_temp_var (temp_var);
 
 			var class_ref = new CCodeFunctionCall (new CCodeIdentifier ("g_type_class_ref"));