Draft of a PPAPI interface for ArrayBuffer.

See the TypedArray spec for reference:
http://www.khronos.org/registry/typedarray/specs/latest/

Things in the spec that I'm omiting:
- slice (Having a view of the ArrayBuffer that has a different offset/length)

TODO in future CLs:
-Implementation for in-process/trusted + tests (almost ready)
-NaCl proxy
-OOP proxy
Later still:
- Support for ArrayBufferView and TypedArray based on that.

BUG=103435
TEST=N/A

Review URL: http://codereview.chromium.org/8502030

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@113355 0039d316-1c4b-4281-b951-d872f2087c98

2 files changed, 123 insertions, 0 deletions

diff --git a/ppapi/cpp/dev/var_array_buffer_dev.cc b/ppapi/cpp/dev/var_array_buffer_dev.cc
new file mode 100644
index 0000000..4ce6215
--- /dev/null
+++ b/ppapi/cpp/dev/var_array_buffer_dev.cc
@@ -0,0 +1,66 @@
+// Copyright (c) 2011 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/cpp/dev/var_array_buffer_dev.h"
+
+#include "ppapi/c/dev/ppb_var_array_buffer_dev.h"
+#include "ppapi/cpp/logging.h"
+#include "ppapi/cpp/module_impl.h"
+
+namespace pp {
+
+namespace {
+
+template <> const char* interface_name<PPB_VarArrayBuffer_Dev>() {
+  return PPB_VAR_ARRAY_BUFFER_DEV_INTERFACE;
+}
+
+}  // namespace
+
+VarArrayBuffer_Dev::VarArrayBuffer_Dev(const Var& var)
+    : Var(var), buffer_(NULL) {
+  if (var.is_array_buffer()) {
+    buffer_ = Map();
+  } else {
+    PP_NOTREACHED();
+    var_ = PP_MakeNull();
+  }
+}
+
+VarArrayBuffer_Dev::VarArrayBuffer_Dev(uint32_t size_in_bytes)
+    : buffer_(NULL) {
+  if (has_interface<PPB_VarArrayBuffer_Dev>()) {
+    var_ = get_interface<PPB_VarArrayBuffer_Dev>()->Create(size_in_bytes);
+    buffer_ = Map();
+  } else {
+    PP_NOTREACHED();
+    var_ = PP_MakeNull();
+  }
+}
+
+uint32_t VarArrayBuffer_Dev::ByteLength() const {
+  if (has_interface<PPB_VarArrayBuffer_Dev>()) {
+    return get_interface<PPB_VarArrayBuffer_Dev>()->ByteLength(var_);
+  }
+  PP_NOTREACHED();
+  return 0;
+}
+
+const void* VarArrayBuffer_Dev::Map() const {
+  return const_cast<VarArrayBuffer_Dev*>(this)->Map();
+}
+
+void* VarArrayBuffer_Dev::Map() {
+  // TODO(dmichael): This is not thread-safe.
+  if (buffer_)
+    return buffer_;
+  if (has_interface<PPB_VarArrayBuffer_Dev>()) {
+    buffer_ = get_interface<PPB_VarArrayBuffer_Dev>()->Map(var_);
+    return buffer_;
+  }
+  PP_NOTREACHED();
+  return 0;
+}
+
+}  // namespace pp
diff --git a/ppapi/cpp/dev/var_array_buffer_dev.h b/ppapi/cpp/dev/var_array_buffer_dev.h
new file mode 100644
index 0000000..6f8c959
--- /dev/null
+++ b/ppapi/cpp/dev/var_array_buffer_dev.h
@@ -0,0 +1,57 @@
+// Copyright (c) 2011 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_VAR_ARRAY_BUFFER_DEV_H_
+#define PPAPI_CPP_DEV_VAR_ARRAY_BUFFER_DEV_H_
+
+#include "ppapi/cpp/var.h"
+
+/// @file
+/// This file defines the API for interacting with an ArrayBuffer.
+
+namespace pp {
+
+/// VarArrayBuffer_Dev provides a way to interact with JavaScript ArrayBuffers,
+/// which represent a contiguous sequence of bytes. Note that
+/// VarArrayBuffer_Devs are not part of the embedding page's DOM, and can only
+/// be shared with JavaScript via pp::Instance's PostMessage and HandleMessage
+/// functions.
+class VarArrayBuffer_Dev : public Var {
+ public:
+  /// Contruct a VarArrayBuffer_Dev given a var for which is_array_buffer() is
+  /// true. This will refer to the same buffer as var, but allows you to access
+  /// methods specific to VarArrayBuffer_Dev.
+  ///
+  /// @param[in] var An array buffer Var.
+  explicit VarArrayBuffer_Dev(const Var& var);
+
+  VarArrayBuffer_Dev(const VarArrayBuffer_Dev& buffer) : Var(buffer) {}
+
+  /// Construct a new VarArrayBuffer_Dev which is size_in_bytes bytes long and
+  /// initialized to zero.
+  ///
+  /// @param[in] size_in_bytes The size of the constructed array in bytes.
+  VarArrayBuffer_Dev(uint32_t size_in_bytes);
+
+  /// Return the length of the VarArrayBuffer_Dev in bytes.
+  ///
+  /// @return The length of the VarArrayBuffer_Dev in bytes.
+  uint32_t ByteLength() const;
+
+  /// Return a pointer to the buffer associated with this VarArrayBuffer_Dev.
+  ///
+  /// @return A pointer to the buffer associated with this VarArrayBuffer_Dev.
+  void* Map();
+  const void* Map() const;
+
+  virtual ~VarArrayBuffer_Dev() {}
+
+ private:
+  // We cache the buffer so that repeated calls to Map() are quick.
+  void* buffer_;
+};
+
+}  // namespace pp
+
+#endif  // PPAPI_CPP_DEV_VAR_ARRAY_BUFFER_DEV_H_