gecko-dev/xpcom/io/nsMultiplexInputStream.cpp

412 lines
12 KiB
C++

/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
/* ***** BEGIN LICENSE BLOCK *****
* Version: MPL 1.1/GPL 2.0/LGPL 2.1
*
* The contents of this file are subject to the Mozilla Public License Version
* 1.1 (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
* http://www.mozilla.org/MPL/
*
* Software distributed under the License is distributed on an "AS IS" basis,
* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
* for the specific language governing rights and limitations under the
* License.
*
* The Original Code is frightening to behold.
*
* The Initial Developer of the Original Code is
* Jonas Sicking.
* Portions created by the Initial Developer are Copyright (C) 2001
* the Initial Developer. All Rights Reserved.
*
* Contributor(s):
* Jonas Sicking <sicking@bigfoot.com>
*
* Alternatively, the contents of this file may be used under the terms of
* either the GNU General Public License Version 2 or later (the "GPL"), or
* the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
* in which case the provisions of the GPL or the LGPL are applicable instead
* of those above. If you wish to allow use of your version of this file only
* under the terms of either the GPL or the LGPL, and not to allow others to
* use your version of this file under the terms of the MPL, indicate your
* decision by deleting the provisions above and replace them with the notice
* and other provisions required by the GPL or the LGPL. If you do not delete
* the provisions above, a recipient may use your version of this file under
* the terms of any one of the MPL, the GPL or the LGPL.
*
* ***** END LICENSE BLOCK ***** */
/**
* The multiplex stream concatenates a list of input streams into a single
* stream.
*/
#include "nsMultiplexInputStream.h"
#include "nsIMultiplexInputStream.h"
#include "nsISeekableStream.h"
#include "nsCOMPtr.h"
#include "nsCOMArray.h"
#include "nsInt64.h"
class nsMultiplexInputStream : public nsIMultiplexInputStream,
public nsISeekableStream
{
public:
nsMultiplexInputStream();
NS_DECL_ISUPPORTS
NS_DECL_NSIINPUTSTREAM
NS_DECL_NSIMULTIPLEXINPUTSTREAM
NS_DECL_NSISEEKABLESTREAM
private:
~nsMultiplexInputStream() {}
struct ReadSegmentsState {
nsIInputStream* mThisStream;
PRUint32 mOffset;
nsWriteSegmentFun mWriter;
void* mClosure;
PRBool mDone;
};
static NS_METHOD ReadSegCb(nsIInputStream* aIn, void* aClosure,
const char* aFromRawSegment, PRUint32 aToOffset,
PRUint32 aCount, PRUint32 *aWriteCount);
nsCOMArray<nsIInputStream> mStreams;
PRUint32 mCurrentStream;
PRBool mStartedReadingCurrent;
nsresult mStatus;
};
NS_IMPL_THREADSAFE_ISUPPORTS3(nsMultiplexInputStream,
nsIMultiplexInputStream,
nsIInputStream,
nsISeekableStream)
nsMultiplexInputStream::nsMultiplexInputStream()
: mCurrentStream(0),
mStartedReadingCurrent(PR_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)
{
PRBool 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)
{
PRBool result = mStreams.RemoveObjectAt(aIndex);
NS_ENSURE_TRUE(result, NS_ERROR_NOT_AVAILABLE);
if (mCurrentStream > aIndex)
--mCurrentStream;
else if (mCurrentStream == aIndex)
mStartedReadingCurrent = PR_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 = PR_FALSE;
}
else {
NS_ASSERTION(aCount >= read, "Read more than requested");
*_retval += read;
aCount -= read;
aBuf += read;
mStartedReadingCurrent = PR_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 = PR_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 = PR_FALSE;
}
else {
NS_ASSERTION(aCount >= read, "Read more than requested");
state.mOffset += read;
aCount -= read;
mStartedReadingCurrent = PR_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 = PR_TRUE;
return rv;
}
/* readonly attribute boolean nonBlocking; */
NS_IMETHODIMP
nsMultiplexInputStream::IsNonBlocking(PRBool *aNonBlocking)
{
PRUint32 len = mStreams.Count();
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 = PR_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;
nsInt64 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;
}
NS_METHOD
nsMultiplexInputStreamConstructor(nsISupports *outer,
REFNSIID iid,
void **result)
{
*result = nsnull;
if (outer)
return NS_ERROR_NO_AGGREGATION;
nsMultiplexInputStream *inst;
NS_NEWXPCOM(inst, nsMultiplexInputStream);
if (!inst)
return NS_ERROR_OUT_OF_MEMORY;
NS_ADDREF(inst);
nsresult rv = inst->QueryInterface(iid, result);
NS_RELEASE(inst);
return rv;
}