Add a ScopedPPVar class for helping to track a reference to a base PP_Var.

This will be used in unit tests and (possibly in the future) son proxy implementation code. This is basically copied from ScopedPPResource.

TEST=none
BUG=none


Review URL: https://chromiumcodereview.appspot.com/10562033

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@142982 0039d316-1c4b-4281-b951-d872f2087c98

3 files changed, 99 insertions, 0 deletions

diff --git a/ppapi/ppapi_shared.gypi b/ppapi/ppapi_shared.gypi
index beecb34..2ed61c1 100644
--- a/ppapi/ppapi_shared.gypi
+++ b/ppapi/ppapi_shared.gypi
@@ -90,6 +90,8 @@
           'shared_impl/resource_tracker.h',
           'shared_impl/scoped_pp_resource.cc',
           'shared_impl/scoped_pp_resource.h',
+          'shared_impl/scoped_pp_var.cc',
+          'shared_impl/scoped_pp_var.h',
           'shared_impl/time_conversion.cc',
           'shared_impl/time_conversion.h',
           'shared_impl/tracked_callback.cc',
diff --git a/ppapi/shared_impl/scoped_pp_var.cc b/ppapi/shared_impl/scoped_pp_var.cc
new file mode 100644
index 0000000..fcd6806
--- /dev/null
+++ b/ppapi/shared_impl/scoped_pp_var.cc
@@ -0,0 +1,50 @@
+// Copyright (c) 2012 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "ppapi/shared_impl/scoped_pp_var.h"
+
+#include "ppapi/shared_impl/ppapi_globals.h"
+#include "ppapi/shared_impl/var_tracker.h"
+
+namespace ppapi {
+
+namespace {
+
+void CallAddRef(const PP_Var& v) {
+  PpapiGlobals::Get()->GetVarTracker()->AddRefVar(v);
+}
+
+void CallRelease(const PP_Var& v) {
+  PpapiGlobals::Get()->GetVarTracker()->ReleaseVar(v);
+}
+
+}  // namespace
+
+ScopedPPVar::ScopedPPVar() : var_(PP_MakeUndefined()) {
+}
+
+ScopedPPVar::ScopedPPVar(const PP_Var& v) : var_(v) {
+  CallAddRef(var_);
+}
+
+ScopedPPVar::ScopedPPVar(const PassRef&, const PP_Var& v) : var_(v) {
+}
+
+ScopedPPVar::ScopedPPVar(const ScopedPPVar& other)
+    : var_(other.var_) {
+  CallAddRef(var_);
+}
+
+ScopedPPVar::~ScopedPPVar() {
+  CallRelease(var_);
+}
+
+ScopedPPVar& ScopedPPVar::operator=(const PP_Var& v) {
+  CallAddRef(v);
+  CallRelease(var_);
+  var_ = v;
+  return *this;
+}
+
+}  // namespace ppapi
diff --git a/ppapi/shared_impl/scoped_pp_var.h b/ppapi/shared_impl/scoped_pp_var.h
new file mode 100644
index 0000000..8079a91
--- /dev/null
+++ b/ppapi/shared_impl/scoped_pp_var.h
@@ -0,0 +1,47 @@
+// Copyright (c) 2012 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef PPAPI_SHARED_IMPL_SCOPED_PP_VAR_H_
+#define PPAPI_SHARED_IMPL_SCOPED_PP_VAR_H_
+
+#include "ppapi/c/pp_var.h"
+#include "ppapi/shared_impl/ppapi_shared_export.h"
+
+namespace ppapi {
+
+class PPAPI_SHARED_EXPORT ScopedPPVar {
+ public:
+  struct PassRef {};
+
+  ScopedPPVar();
+
+  // Takes one reference to the given resource.
+  explicit ScopedPPVar(const PP_Var& v);
+
+  // Assumes responsibility for one ref that the var already has.
+  ScopedPPVar(const PassRef&, const PP_Var& v);
+
+  // Implicit copy constructor allowed.
+  ScopedPPVar(const ScopedPPVar& other);
+
+  ~ScopedPPVar();
+
+  ScopedPPVar& operator=(const PP_Var& r);
+  ScopedPPVar& operator=(const ScopedPPVar& other) {
+    return operator=(other.var_);
+  }
+
+  const PP_Var& get() const { return var_; }
+
+  // Returns the PP_Var, passing the reference to the caller. This class
+  // will no longer hold the var.
+  PP_Var Release();
+
+ private:
+  PP_Var var_;
+};
+
+}  // namespace ppapi
+
+#endif  // PPAPI_SHARED_IMPL_SCOPED_PP_VAR_H_