gecko-dev/xpcom/io/nsMultiplexInputStream.cpp

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13 KiB
C++
Исходник Обычный вид История

/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
2012-05-21 15:12:37 +04:00
/* 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/. */
/**
* The multiplex stream concatenates a list of input streams into a single
* stream.
*/
#include "IPC/IPCMessageUtils.h"
#include "mozilla/net/NeckoMessageUtils.h"
#include "nsMultiplexInputStream.h"
#include "nsIMultiplexInputStream.h"
#include "nsISeekableStream.h"
#include "nsCOMPtr.h"
#include "nsCOMArray.h"
#include "nsIIPCSerializable.h"
#include "nsIClassInfoImpl.h"
class nsMultiplexInputStream : public nsIMultiplexInputStream,
public nsISeekableStream,
public nsIIPCSerializable
{
public:
nsMultiplexInputStream();
NS_DECL_ISUPPORTS
NS_DECL_NSIINPUTSTREAM
NS_DECL_NSIMULTIPLEXINPUTSTREAM
NS_DECL_NSISEEKABLESTREAM
NS_DECL_NSIIPCSERIALIZABLE
private:
~nsMultiplexInputStream() {}
struct ReadSegmentsState {
nsIInputStream* mThisStream;
PRUint32 mOffset;
nsWriteSegmentFun mWriter;
void* mClosure;
bool mDone;
};
static NS_METHOD ReadSegCb(nsIInputStream* aIn, void* aClosure,
const char* aFromRawSegment, PRUint32 aToOffset,
PRUint32 aCount, PRUint32 *aWriteCount);
nsCOMArray<nsIInputStream> mStreams;
PRUint32 mCurrentStream;
bool mStartedReadingCurrent;
nsresult mStatus;
};
NS_IMPL_THREADSAFE_ADDREF(nsMultiplexInputStream)
NS_IMPL_THREADSAFE_RELEASE(nsMultiplexInputStream)
NS_IMPL_CLASSINFO(nsMultiplexInputStream, NULL, nsIClassInfo::THREADSAFE,
NS_MULTIPLEXINPUTSTREAM_CID)
NS_IMPL_QUERY_INTERFACE4_CI(nsMultiplexInputStream,
nsIMultiplexInputStream,
nsIInputStream,
nsISeekableStream,
nsIIPCSerializable)
NS_IMPL_CI_INTERFACE_GETTER4(nsMultiplexInputStream,
nsIMultiplexInputStream,
nsIInputStream,
nsISeekableStream,
nsIIPCSerializable)
nsMultiplexInputStream::nsMultiplexInputStream()
: mCurrentStream(0),
mStartedReadingCurrent(false),
mStatus(NS_OK)
{
}
/* readonly attribute unsigned long count; */
NS_IMETHODIMP
nsMultiplexInputStream::GetCount(PRUint32 *aCount)
{
*aCount = mStreams.Count();
return NS_OK;
}
/* void appendStream (in nsIInputStream stream); */
NS_IMETHODIMP
nsMultiplexInputStream::AppendStream(nsIInputStream *aStream)
{
return mStreams.AppendObject(aStream) ? NS_OK : NS_ERROR_OUT_OF_MEMORY;
}
/* void insertStream (in nsIInputStream stream, in unsigned long index); */
NS_IMETHODIMP
nsMultiplexInputStream::InsertStream(nsIInputStream *aStream, PRUint32 aIndex)
{
bool result = mStreams.InsertObjectAt(aStream, aIndex);
NS_ENSURE_TRUE(result, NS_ERROR_OUT_OF_MEMORY);
if (mCurrentStream > aIndex ||
(mCurrentStream == aIndex && mStartedReadingCurrent))
++mCurrentStream;
return NS_OK;
}
/* void removeStream (in unsigned long index); */
NS_IMETHODIMP
nsMultiplexInputStream::RemoveStream(PRUint32 aIndex)
{
bool result = mStreams.RemoveObjectAt(aIndex);
NS_ENSURE_TRUE(result, NS_ERROR_NOT_AVAILABLE);
if (mCurrentStream > aIndex)
--mCurrentStream;
else if (mCurrentStream == aIndex)
mStartedReadingCurrent = false;
return NS_OK;
}
/* nsIInputStream getStream (in unsigned long index); */
NS_IMETHODIMP
nsMultiplexInputStream::GetStream(PRUint32 aIndex, nsIInputStream **_retval)
{
*_retval = mStreams.SafeObjectAt(aIndex);
NS_ENSURE_TRUE(*_retval, NS_ERROR_NOT_AVAILABLE);
NS_ADDREF(*_retval);
return NS_OK;
}
/* void close (); */
NS_IMETHODIMP
nsMultiplexInputStream::Close()
{
mStatus = NS_BASE_STREAM_CLOSED;
nsresult rv = NS_OK;
PRUint32 len = mStreams.Count();
for (PRUint32 i = 0; i < len; ++i) {
nsresult rv2 = mStreams[i]->Close();
// We still want to close all streams, but we should return an error
if (NS_FAILED(rv2))
rv = rv2;
}
return rv;
}
/* unsigned long available (); */
NS_IMETHODIMP
nsMultiplexInputStream::Available(PRUint32 *_retval)
{
if (NS_FAILED(mStatus))
return mStatus;
nsresult rv;
PRUint32 avail = 0;
PRUint32 len = mStreams.Count();
for (PRUint32 i = mCurrentStream; i < len; i++) {
PRUint32 streamAvail;
rv = mStreams[i]->Available(&streamAvail);
NS_ENSURE_SUCCESS(rv, rv);
avail += streamAvail;
}
*_retval = avail;
return NS_OK;
}
/* [noscript] unsigned long read (in charPtr buf, in unsigned long count); */
NS_IMETHODIMP
nsMultiplexInputStream::Read(char * aBuf, PRUint32 aCount, PRUint32 *_retval)
{
// It is tempting to implement this method in terms of ReadSegments, but
// that would prevent this class from being used with streams that only
// implement Read (e.g., file streams).
*_retval = 0;
if (mStatus == NS_BASE_STREAM_CLOSED)
return NS_OK;
if (NS_FAILED(mStatus))
return mStatus;
nsresult rv = NS_OK;
PRUint32 len = mStreams.Count();
while (mCurrentStream < len && aCount) {
PRUint32 read;
rv = mStreams[mCurrentStream]->Read(aBuf, aCount, &read);
// XXX some streams return NS_BASE_STREAM_CLOSED to indicate EOF.
// (This is a bug in those stream implementations)
if (rv == NS_BASE_STREAM_CLOSED) {
NS_NOTREACHED("Input stream's Read method returned NS_BASE_STREAM_CLOSED");
rv = NS_OK;
read = 0;
}
else if (NS_FAILED(rv))
break;
if (read == 0) {
++mCurrentStream;
mStartedReadingCurrent = false;
}
else {
NS_ASSERTION(aCount >= read, "Read more than requested");
*_retval += read;
aCount -= read;
aBuf += read;
mStartedReadingCurrent = true;
}
}
return *_retval ? NS_OK : rv;
}
/* [noscript] unsigned long readSegments (in nsWriteSegmentFun writer,
* in voidPtr closure,
* in unsigned long count); */
NS_IMETHODIMP
nsMultiplexInputStream::ReadSegments(nsWriteSegmentFun aWriter, void *aClosure,
PRUint32 aCount, PRUint32 *_retval)
{
if (mStatus == NS_BASE_STREAM_CLOSED) {
*_retval = 0;
return NS_OK;
}
if (NS_FAILED(mStatus))
return mStatus;
NS_ASSERTION(aWriter, "missing aWriter");
nsresult rv = NS_OK;
ReadSegmentsState state;
state.mThisStream = this;
state.mOffset = 0;
state.mWriter = aWriter;
state.mClosure = aClosure;
state.mDone = false;
PRUint32 len = mStreams.Count();
while (mCurrentStream < len && aCount) {
PRUint32 read;
rv = mStreams[mCurrentStream]->ReadSegments(ReadSegCb, &state, aCount, &read);
// XXX some streams return NS_BASE_STREAM_CLOSED to indicate EOF.
// (This is a bug in those stream implementations)
if (rv == NS_BASE_STREAM_CLOSED) {
NS_NOTREACHED("Input stream's Read method returned NS_BASE_STREAM_CLOSED");
rv = NS_OK;
read = 0;
}
// if |aWriter| decided to stop reading segments...
if (state.mDone || NS_FAILED(rv))
break;
// if stream is empty, then advance to the next stream.
if (read == 0) {
++mCurrentStream;
mStartedReadingCurrent = false;
}
else {
NS_ASSERTION(aCount >= read, "Read more than requested");
state.mOffset += read;
aCount -= read;
mStartedReadingCurrent = true;
}
}
// if we successfully read some data, then this call succeeded.
*_retval = state.mOffset;
return state.mOffset ? NS_OK : rv;
}
NS_METHOD
nsMultiplexInputStream::ReadSegCb(nsIInputStream* aIn, void* aClosure,
const char* aFromRawSegment,
PRUint32 aToOffset, PRUint32 aCount,
PRUint32 *aWriteCount)
{
nsresult rv;
ReadSegmentsState* state = (ReadSegmentsState*)aClosure;
rv = (state->mWriter)(state->mThisStream,
state->mClosure,
aFromRawSegment,
aToOffset + state->mOffset,
aCount,
aWriteCount);
if (NS_FAILED(rv))
state->mDone = true;
return rv;
}
/* readonly attribute boolean nonBlocking; */
NS_IMETHODIMP
nsMultiplexInputStream::IsNonBlocking(bool *aNonBlocking)
{
PRUint32 len = mStreams.Count();
if (len == 0) {
// Claim to be non-blocking, since we won't block the caller.
// On the other hand we'll never return NS_BASE_STREAM_WOULD_BLOCK,
// so maybe we should claim to be blocking? It probably doesn't
// matter in practice.
*aNonBlocking = true;
return NS_OK;
}
for (PRUint32 i = 0; i < len; ++i) {
nsresult rv = mStreams[i]->IsNonBlocking(aNonBlocking);
NS_ENSURE_SUCCESS(rv, rv);
// If one is non-blocking the entire stream becomes non-blocking
// (except that we don't implement nsIAsyncInputStream, so there's
// not much for the caller to do if Read returns "would block")
if (*aNonBlocking)
return NS_OK;
}
return NS_OK;
}
/* void seek (in PRInt32 whence, in PRInt32 offset); */
NS_IMETHODIMP
nsMultiplexInputStream::Seek(PRInt32 aWhence, PRInt64 aOffset)
{
if (NS_FAILED(mStatus))
return mStatus;
nsresult rv;
// rewinding to start is easy, and should be the most common case
if (aWhence == NS_SEEK_SET && aOffset == 0)
{
PRUint32 i, last;
last = mStartedReadingCurrent ? mCurrentStream+1 : mCurrentStream;
for (i = 0; i < last; ++i) {
nsCOMPtr<nsISeekableStream> stream = do_QueryInterface(mStreams[i]);
NS_ENSURE_TRUE(stream, NS_ERROR_NO_INTERFACE);
rv = stream->Seek(NS_SEEK_SET, 0);
NS_ENSURE_SUCCESS(rv, rv);
}
mCurrentStream = 0;
mStartedReadingCurrent = false;
return NS_OK;
}
// other Seeks not implemented yet
return NS_ERROR_NOT_IMPLEMENTED;
}
/* PRUint32 tell (); */
NS_IMETHODIMP
nsMultiplexInputStream::Tell(PRInt64 *_retval)
{
if (NS_FAILED(mStatus))
return mStatus;
nsresult rv;
PRInt64 ret64 = 0;
PRUint32 i, last;
last = mStartedReadingCurrent ? mCurrentStream+1 : mCurrentStream;
for (i = 0; i < last; ++i) {
nsCOMPtr<nsISeekableStream> stream = do_QueryInterface(mStreams[i]);
NS_ENSURE_TRUE(stream, NS_ERROR_NO_INTERFACE);
PRInt64 pos;
rv = stream->Tell(&pos);
NS_ENSURE_SUCCESS(rv, rv);
ret64 += pos;
}
*_retval = ret64;
return NS_OK;
}
/* void setEOF (); */
NS_IMETHODIMP
nsMultiplexInputStream::SetEOF()
{
return NS_ERROR_NOT_IMPLEMENTED;
}
nsresult
nsMultiplexInputStreamConstructor(nsISupports *outer,
REFNSIID iid,
void **result)
{
*result = nsnull;
if (outer)
return NS_ERROR_NO_AGGREGATION;
nsMultiplexInputStream *inst = new nsMultiplexInputStream();
if (!inst)
return NS_ERROR_OUT_OF_MEMORY;
NS_ADDREF(inst);
nsresult rv = inst->QueryInterface(iid, result);
NS_RELEASE(inst);
return rv;
}
bool
nsMultiplexInputStream::Read(const IPC::Message *aMsg, void **aIter)
{
using IPC::ReadParam;
PRUint32 count;
if (!ReadParam(aMsg, aIter, &count))
return false;
for (PRUint32 i = 0; i < count; i++) {
IPC::InputStream inputStream;
if (!ReadParam(aMsg, aIter, &inputStream))
return false;
nsCOMPtr<nsIInputStream> stream(inputStream);
nsresult rv = AppendStream(stream);
if (NS_FAILED(rv))
return false;
}
if (!ReadParam(aMsg, aIter, &mCurrentStream) ||
!ReadParam(aMsg, aIter, &mStartedReadingCurrent) ||
!ReadParam(aMsg, aIter, &mStatus))
return false;
return true;
}
void
nsMultiplexInputStream::Write(IPC::Message *aMsg)
{
using IPC::WriteParam;
PRUint32 count = mStreams.Count();
WriteParam(aMsg, count);
for (PRUint32 i = 0; i < count; i++) {
IPC::InputStream inputStream(mStreams.ObjectAt(i));
WriteParam(aMsg, inputStream);
}
WriteParam(aMsg, mCurrentStream);
WriteParam(aMsg, mStartedReadingCurrent);
WriteParam(aMsg, mStatus);
}