App APIs in Pepper: C++ APIs

ppapi/cpp/dev/string_wrapper_dev.h

+// Copyright (c) 2013 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_CPP_DEV_STRING_WRAPPER_DEV_H_
+#define PPAPI_CPP_DEV_STRING_WRAPPER_DEV_H_
+
+#include <string>
+
+#include "ppapi/c/pp_var.h"
+#include "ppapi/cpp/dev/may_own_ptr_dev.h"
+
+namespace pp {
+namespace internal {
+
+// An optional string backed by a PP_Var. When the string is not set, the type
+// of the PP_Var is set to PP_VARTYPE_UNDEFINED; otherwise, it is set to
+// PP_VARTYPE_STRING.
+class OptionalStringWrapper {
+ public:
+  OptionalStringWrapper();
+
+  explicit OptionalStringWrapper(const std::string& value);
+
+  // Creates an accessor to |storage| but doesn't take ownership of it.
+  // |storage| must live longer than this object. The contents pointed to by
+  // |storage| must be zero-initialized by the caller.
+  //
+  // Although this object doesn't own the memory of |storage|, it manages the
+  // ref count and sets the var to undefined when destructed.
+  OptionalStringWrapper(PP_Var* storage, NotOwned);
+
+  OptionalStringWrapper(const OptionalStringWrapper& other);
+
+  ~OptionalStringWrapper();
+
+  OptionalStringWrapper& operator=(const OptionalStringWrapper& other);
+  OptionalStringWrapper& operator=(const PP_Var& other);
+
+  bool is_set() const;
+  void unset();
+  std::string get() const;
+  void set(const std::string& value);
+
+  const PP_Var& ToVar() const { return *storage_; }
+
+  // Sets the underlying PP_Var to undefined before returning it.
+  PP_Var* StartRawUpdate();
+  void EndRawUpdate();
+
+ private:
+  MayOwnPtr<PP_Var> storage_;
+};
+
+// A string backed by a PP_Var whose type is PP_VARTYPE_STRING.
+class StringWrapper {
+ public:
+  StringWrapper();
+
+  explicit StringWrapper(const std::string& value);
+
+  // Creates an accessor to |storage| but doesn't take ownership of it.
+  // |storage| must live longer than this object. The contents pointed to by
+  // |storage| must be zero-initialized by the caller.
+  //
+  // Although this object doesn't own the memory of |storage|, it manages the
+  // ref count and sets the var to undefined when destructed.
+  StringWrapper(PP_Var* storage, NotOwned);
+
+  StringWrapper(const StringWrapper& other);
+
+  ~StringWrapper();
+
+  StringWrapper& operator=(const StringWrapper& other);
+  StringWrapper& operator=(const PP_Var& other);
+
+  std::string get() const { return storage_.get(); }
+  void set(const std::string& value) { return storage_.set(value); }
+
+  const PP_Var& ToVar() const { return storage_.ToVar(); }
+
+  // Sets the underlying PP_Var to undefined before returning it.
+  PP_Var* StartRawUpdate();
+  // If the underlying PP_Var wasn't updated to a valid string, sets it to an
+  // empty string.
+  void EndRawUpdate();
+
+ private:
+  OptionalStringWrapper storage_;
+};
+
+}  // namespace internal
+}  // namespace pp
+
+#endif  // PPAPI_CPP_DEV_STRING_WRAPPER_DEV_H_