9db847b43c
Review URL: http://codereview.chromium.org/9395039 git-svn-id: svn://svn.chromium.org/chrome/trunk/src@122636 0039d316-1c4b-4281-b951-d872f2087c98
96 lines
3.5 KiB
C++
96 lines
3.5 KiB
C++
// Copyright (c) 2012 The Chromium Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file.
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#ifndef PPAPI_CPP_VAR_ARRAY_BUFFER_H_
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#define PPAPI_CPP_VAR_ARRAY_BUFFER_H_
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#include "ppapi/cpp/var.h"
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/// @file
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/// This file defines the API for interacting with a JavaScript ArrayBuffer.
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namespace pp {
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/// <code>VarArrayBuffer</code> provides a way to interact with JavaScript
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/// ArrayBuffers, which represent a contiguous sequence of bytes. Note that
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/// these vars are not part of the embedding page's DOM, and can only be
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/// shared with JavaScript using the <code>PostMessage</code> and
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/// <code>HandleMessage</code> functions of <code>Instance</code>.
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class VarArrayBuffer : public Var {
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public:
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/// Contruct a <code>VarArrayBuffer</code> given a var for which
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/// is_array_buffer() is true. This will refer to the same
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/// <code>ArrayBuffer</code> as var, but allows you to access methods
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/// specific to <code>VarArrayBuffer</code>.
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///
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/// @param[in] var An <code>ArrayBuffer</code> var.
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explicit VarArrayBuffer(const Var& var);
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/// Construct a new <code>VarArrayBuffer_Dev</code> which is
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/// <code>size_in_bytes</code> bytes long and initialized to zero.
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///
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/// @param[in] size_in_bytes The size of the constructed
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/// <code>ArrayBuffer</code> in bytes.
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explicit VarArrayBuffer(uint32_t size_in_bytes);
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/// Copy constructor.
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VarArrayBuffer(const VarArrayBuffer& buffer) : Var(buffer) {}
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virtual ~VarArrayBuffer() {}
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/// This function assigns one <code>VarArrayBuffer</code> to another
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/// <code>VarArrayBuffer</code>.
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///
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/// @param[in] other The <code>VarArrayBuffer</code> to be assigned.
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///
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/// @return The resulting <code>VarArrayBuffer</code>.
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VarArrayBuffer& operator=(const VarArrayBuffer& other);
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/// This function assigns one <code>VarArrayBuffer</code> to another
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/// <code>VarArrayBuffer</code>. A Var's assignment operator is overloaded
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/// here so that we can check for assigning a non-ArrayBuffer var to a
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/// <code>VarArrayBuffer_Dev</code>.
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///
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/// @param[in] other The <code>VarArrayBuffer</code> to be assigned.
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///
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/// @return The resulting <code>VarArrayBuffer</code> (as a Var&).
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virtual Var& operator=(const Var& other);
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/// ByteLength() retrieves the length of the <code>VarArrayBuffer</code> in
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/// bytes.
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///
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/// @return The length of the <code>VarArrayBuffer</code> in bytes.
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uint32_t ByteLength() const;
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/// Map() maps the <code>ArrayBuffer</code> in to the module's address space
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/// and returns a pointer to the beginning of the internal buffer for
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/// this <code>ArrayBuffer</code>.
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///
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/// Note that calling Map() can be a relatively expensive operation. Use care
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/// when calling it in performance-critical code. For example, you should call
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/// it only once when looping over an <code>ArrayBuffer</code>.
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///
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/// <strong>Example:</strong>
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///
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/// @code
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/// char* data = static_cast<char*>(array_buffer_var.Map());
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/// uint32_t byte_length = array_buffer_var.ByteLength();
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/// for (uint32_t i = 0; i < byte_length; ++i)
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/// data[i] = 'A';
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/// @endcode
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///
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/// @return A pointer to the internal buffer for this
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/// <code>ArrayBuffer</code>.
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void* Map();
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/// Unmap() unmaps this <code>ArrayBuffer</code> var from the module address
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/// space. Use this if you want to save memory but might want to call Map()
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/// to map the buffer again later.
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void Unmap();
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};
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} // namespace pp
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#endif // PPAPI_CPP_VAR_ARRAY_BUFFER_H_
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