/* Copyright 2012 The Chromium Authors
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
/**
* This file defines the <code>PPB_VarArrayBuffer</code> struct providing
* a way to interact with JavaScript ArrayBuffers.
*/
label Chrome {
M18 = 1.0
};
/**
* The <code>PPB_VarArrayBuffer</code> interface provides a way to interact
* with JavaScript ArrayBuffers, which represent a contiguous sequence of
* bytes. Use <code>PPB_Var</code> to manage the reference count for a
* <code>VarArrayBuffer</code>. Note that these Vars are not part of the
* embedding page's DOM, and can only be shared with JavaScript using the
* <code>PostMessage</code> and <code>HandleMessage</code> functions of
* <code>pp::Instance</code>.
*/
[macro="PPB_VAR_ARRAY_BUFFER_INTERFACE"]
interface PPB_VarArrayBuffer {
/**
* Create() creates a zero-initialized <code>VarArrayBuffer</code>.
*
* @param[in] size_in_bytes The size of the <code>ArrayBuffer</code> to
* be created.
*
* @return A <code>PP_Var</code> representing a <code>VarArrayBuffer</code>
* of the requested size and with a reference count of 1.
*/
PP_Var Create([in] uint32_t size_in_bytes);
/**
* ByteLength() retrieves the length of the <code>VarArrayBuffer</code> in
* bytes. On success, <code>byte_length</code> is set to the length of the
* given <code>ArrayBuffer</code> var. On failure, <code>byte_length</code>
* is unchanged (this could happen, for instance, if the given
* <code>PP_Var</code> is not of type <code>PP_VARTYPE_ARRAY_BUFFER</code>).
* Note that ByteLength() will successfully retrieve the size of an
* <code>ArrayBuffer</code> even if the <code>ArrayBuffer</code> is not
* currently mapped.
*
* @param[in] array The <code>ArrayBuffer</code> whose length should be
* returned.
*
* @param[out] byte_length A variable which is set to the length of the given
* <code>ArrayBuffer</code> on success.
*
* @return <code>PP_TRUE</code> on success, <code>PP_FALSE</code> on failure.
*/
PP_Bool ByteLength([in] PP_Var array, [out] uint32_t byte_length);
/**
* Map() maps the <code>ArrayBuffer</code> in to the module's address space
* and returns a pointer to the beginning of the buffer for the given
* <code>ArrayBuffer PP_Var</code>. ArrayBuffers are copied when transmitted,
* so changes to the underlying memory are not automatically available to
* the embedding page.
*
* Note that calling Map() can be a relatively expensive operation. Use care
* when calling it in performance-critical code. For example, you should call
* it only once when looping over an <code>ArrayBuffer</code>.
*
* <strong>Example:</strong>
*
* @code
* char* data = (char*)(array_buffer_if.Map(array_buffer_var));
* uint32_t byte_length = 0;
* PP_Bool ok = array_buffer_if.ByteLength(array_buffer_var, &byte_length);
* if (!ok)
* return DoSomethingBecauseMyVarIsNotAnArrayBuffer();
* for (uint32_t i = 0; i < byte_length; ++i)
* data[i] = 'A';
* @endcode
*
* @param[in] array The <code>ArrayBuffer</code> whose internal buffer should
* be returned.
*
* @return A pointer to the internal buffer for this
* <code>ArrayBuffer</code>. Returns <code>NULL</code>
* if the given <code>PP_Var</code> is not of type
* <code>PP_VARTYPE_ARRAY_BUFFER</code>.
*/
mem_t Map([in] PP_Var array);
/**
* Unmap() unmaps the given <code>ArrayBuffer</code> var from the module
* address space. Use this if you want to save memory but might want to call
* Map() to map the buffer again later. The <code>PP_Var</code> remains valid
* and should still be released using <code>PPB_Var</code> when you are done
* with the <code>ArrayBuffer</code>.
*
* @param[in] array The <code>ArrayBuffer</code> to be released.
*/
void Unmap([in] PP_Var array);
};
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