gecko-dev/xpcom/io/SlicedInputStream.h

86 lines
2.8 KiB
C++

/* -*- 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 SlicedInputStream_h
#define SlicedInputStream_h
#include "mozilla/Attributes.h"
#include "nsCOMPtr.h"
#include "nsIAsyncInputStream.h"
#include "nsICloneableInputStream.h"
#include "nsIIPCSerializableInputStream.h"
#include "nsISeekableStream.h"
namespace mozilla {
// A wrapper for a slice of an underlying input stream.
class SlicedInputStream final : public nsIAsyncInputStream
, public nsICloneableInputStream
, public nsIIPCSerializableInputStream
, public nsISeekableStream
, public nsIInputStreamCallback
{
public:
NS_DECL_THREADSAFE_ISUPPORTS
NS_DECL_NSIINPUTSTREAM
NS_DECL_NSIASYNCINPUTSTREAM
NS_DECL_NSICLONEABLEINPUTSTREAM
NS_DECL_NSIIPCSERIALIZABLEINPUTSTREAM
NS_DECL_NSISEEKABLESTREAM
NS_DECL_NSIINPUTSTREAMCALLBACK
// Create an input stream whose data comes from a slice of aInputStream. The
// slice begins at aStart bytes beyond aInputStream's current position, and
// extends for a maximum of aLength bytes. If aInputStream contains fewer
// than aStart bytes, reading from SlicedInputStream returns no data. If
// aInputStream contains more than aStart bytes, but fewer than aStart +
// aLength bytes, reading from SlicedInputStream returns as many bytes as can
// be consumed from aInputStream after reading aLength bytes.
//
// aInputStream should not be read from after constructing a
// SlicedInputStream wrapper around it.
SlicedInputStream(already_AddRefed<nsIInputStream> aInputStream,
uint64_t aStart, uint64_t aLength);
// This CTOR is meant to be used just for IPC.
SlicedInputStream();
private:
~SlicedInputStream();
void
SetSourceStream(already_AddRefed<nsIInputStream> aInputStream);
nsresult
RunAsyncWaitCallback();
nsCOMPtr<nsIInputStream> mInputStream;
// Raw pointers because these are just QI of mInputStream.
nsICloneableInputStream* mWeakCloneableInputStream;
nsIIPCSerializableInputStream* mWeakIPCSerializableInputStream;
nsISeekableStream* mWeakSeekableInputStream;
nsIAsyncInputStream* mWeakAsyncInputStream;
uint64_t mStart;
uint64_t mLength;
uint64_t mCurPos;
bool mClosed;
// These four are used for AsyncWait.
nsCOMPtr<nsIInputStreamCallback> mAsyncWaitCallback;
nsCOMPtr<nsIEventTarget> mAsyncWaitEventTarget;
uint32_t mAsyncWaitFlags;
uint32_t mAsyncWaitRequestedCount;
};
} // mozilla namespace
#endif // SlicedInputStream_h