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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#ifndef mozilla_SeekableStreamWrapper_h
#define mozilla_SeekableStreamWrapper_h
#include "mozilla/Assertions.h"
#include "mozilla/Mutex.h"
#include "nsCOMPtr.h"
#include "nsIAsyncInputStream.h"
#include "nsISeekableStream.h"
#include "nsICloneableInputStream.h"
#include "nsIIPCSerializableInputStream.h"
#include "nsIInputStreamLength.h"
#include "nsIBufferedStreams.h"
namespace mozilla {
// Adapter class which converts an input stream implementing
// `nsICloneableInputStream`, such as `nsPipe`, into a stream implementing
// `nsISeekableStream`. This is done by keeping a clone of the original unwound
// input stream to allow rewinding the stream back to its original position.
class SeekableStreamWrapper final : public nsIAsyncInputStream,
public nsISeekableStream,
public nsICloneableInputStream,
public nsIInputStreamLength,
public nsIAsyncInputStreamLength,
public nsIIPCSerializableInputStream,
public nsIBufferedInputStream {
NS_DECL_THREADSAFE_ISUPPORTS
NS_DECL_NSIINPUTSTREAM
NS_DECL_NSIASYNCINPUTSTREAM
NS_DECL_NSITELLABLESTREAM
NS_DECL_NSISEEKABLESTREAM
NS_DECL_NSICLONEABLEINPUTSTREAM
NS_DECL_NSIINPUTSTREAMLENGTH
NS_DECL_NSIASYNCINPUTSTREAMLENGTH
NS_DECL_NSIIPCSERIALIZABLEINPUTSTREAM
NS_DECL_NSIBUFFEREDINPUTSTREAM
public:
/**
* This function returns a nsIInputStream which is known to implement
* nsISeekableStream. This will return |aSource| if it already implements
* nsISeekableStream, and will wrap it if it does not.
*
* If the original stream implements `nsICloneableInputStream`, this will be
* used to implement the rewinding functionality necessary for
* `nsISeekableStream`, otherwise it will be copied into a `nsPipe`.
*/
static nsresult MaybeWrap(already_AddRefed<nsIInputStream> aOriginal,
nsIInputStream** aResult);
private:
SeekableStreamWrapper(nsICloneableInputStream* aOriginal,
nsIInputStream* aCurrent)
: mOriginal(aOriginal), mCurrent(aCurrent) {
MOZ_ASSERT(mOriginal->GetCloneable());
}
~SeekableStreamWrapper() = default;
template <typename T>
nsCOMPtr<T> StreamAs();
template <typename M>
void SerializeInternal(mozilla::ipc::InputStreamParams& aParams,
FileDescriptorArray& aFileDescriptors,
bool aDelayedStart, uint32_t aMaxSize,
uint32_t* aSizeUsed, M* aManager);
bool IsAsyncInputStream();
bool IsInputStreamLength();
bool IsAsyncInputStreamLength();
bool IsIPCSerializableInputStream();
bool IsBufferedInputStream();
// mOriginal is immutable after creation, and is not guarded by `mMutex`.
nsCOMPtr<nsICloneableInputStream> mOriginal;
// This mutex guards `mCurrent`.
Mutex mMutex{"SeekableStreamWrapper"};
nsCOMPtr<nsIInputStream> mCurrent;
};
} // namespace mozilla
#endif // mozilla_SeekableStreamWrapper_h