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// Copyright 2019 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef THIRD_PARTY_BLINK_RENDERER_MODULES_WEBCODECS_ARRAY_BUFFER_UTIL_H_
#define THIRD_PARTY_BLINK_RENDERER_MODULES_WEBCODECS_ARRAY_BUFFER_UTIL_H_
#include "base/compiler_specific.h"
#include "base/containers/span.h"
#include "base/memory/raw_ptr_exclusion.h"
#include "base/types/to_address.h"
#include "media/base/decoder_buffer.h"
#include "third_party/blink/renderer/bindings/core/v8/v8_union_arraybufferallowshared_arraybufferviewallowshared.h"
#include "third_party/blink/renderer/core/typed_arrays/array_buffer/array_buffer_contents.h"
#include "third_party/blink/renderer/core/typed_arrays/dom_array_buffer.h"
#include "third_party/blink/renderer/platform/bindings/exception_state.h"
namespace blink {
using AllowSharedBufferSource =
V8UnionArrayBufferAllowSharedOrArrayBufferViewAllowShared;
// Helper function for turning various DOMArray-like things into a pointer+size.
template <typename T>
base::span<T> AsSpan(const AllowSharedBufferSource* buffer_union) {
switch (buffer_union->GetContentType()) {
case AllowSharedBufferSource::ContentType::kArrayBufferAllowShared: {
auto* buffer = buffer_union->GetAsArrayBufferAllowShared();
return (buffer && !buffer->IsDetached())
? UNSAFE_TODO(base::span<T>(
reinterpret_cast<T*>(buffer->DataMaybeShared()),
buffer->ByteLength()))
: base::span<T>();
}
case AllowSharedBufferSource::ContentType::kArrayBufferViewAllowShared: {
auto* buffer = buffer_union->GetAsArrayBufferViewAllowShared().Get();
return (buffer && !buffer->IsDetached())
? UNSAFE_TODO(base::span<T>(
reinterpret_cast<T*>(buffer->BaseAddressMaybeShared()),
buffer->byteLength()))
: base::span<T>();
}
}
}
// Ensures that the underlying memory for `buffer_union` remains valid
// (owned by a returned instance of ArrayBufferContents)
// even if the buffer is detached or truncated by client activity.
// Returns a valid ArrayBufferContents only for shared buffers, otherwise
// returns an empty ArrayBufferContents.
ArrayBufferContents PinSharedArrayBufferContent(
const AllowSharedBufferSource* buffer_union);
// 1. Check if any on the array buffers from the `transfer_list` contain
// `data_range` and return contents of that array buffer.
// 2. Detach all array buffers from in the `transfer_list`
ArrayBufferContents TransferArrayBufferForSpan(
const HeapVector<Member<DOMArrayBuffer>>& transfer_list,
base::span<const uint8_t> data_range,
ExceptionState& exception_state,
v8::Isolate* isolate);
// A wrapper around `ArrayBuffer` contents that allows to transfer ownership
// to `DecoderBuffer`.
class ArrayBufferContentsExternalMemory
: public media::DecoderBuffer::ExternalMemory {
public:
explicit ArrayBufferContentsExternalMemory(ArrayBufferContents contents,
base::span<const uint8_t> span)
: contents_(std::move(contents)), span_(span) {
// Check that `span` refers to the memory inside `contents`.
auto* contents_data = static_cast<const uint8_t*>(contents_.Data());
CHECK_GE(base::to_address(span.begin()), contents_data);
CHECK_LE(base::to_address(span.end()),
UNSAFE_TODO(contents_data + contents_.DataLength()));
}
const base::span<const uint8_t> Span() const override { return span_; }
private:
ArrayBufferContents contents_;
// TODO(367764863) Rewrite to base::raw_span.
RAW_PTR_EXCLUSION const base::span<const uint8_t> span_;
};
} // namespace blink
#endif // THIRD_PARTY_BLINK_RENDERER_MODULES_WEBCODECS_ARRAY_BUFFER_UTIL_H_
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