pjs/xpcom/io/nsInputStreamTee.cpp

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C++

/* -*- Mode: C++; tab-width: 2; 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 mozilla.org code.
*
* The Initial Developer of the Original Code is
* Netscape Communications Corporation.
* Portions created by the Initial Developer are Copyright (C) 2001
* the Initial Developer. All Rights Reserved.
*
* Contributor(s):
* Darin Fisher <darin@netscape.com> (original author)
*
* Alternatively, the contents of this file may be used under the terms of
* either of 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 ***** */
#include <stdlib.h>
#include "prlog.h"
#include "mozilla/Mutex.h"
#include "nsIInputStreamTee.h"
#include "nsIInputStream.h"
#include "nsIOutputStream.h"
#include "nsCOMPtr.h"
#include "nsAutoPtr.h"
#include "nsIEventTarget.h"
#include "nsThreadUtils.h"
using namespace mozilla;
#ifdef PR_LOGGING
static PRLogModuleInfo* gInputStreamTeeLog = PR_NewLogModule("nsInputStreamTee");
#define LOG(args) PR_LOG(gInputStreamTeeLog, PR_LOG_DEBUG, args)
#else
#define LOG(args)
#endif
class nsInputStreamTee : public nsIInputStreamTee
{
public:
NS_DECL_ISUPPORTS
NS_DECL_NSIINPUTSTREAM
NS_DECL_NSIINPUTSTREAMTEE
nsInputStreamTee();
bool SinkIsValid();
void InvalidateSink();
private:
~nsInputStreamTee() {}
nsresult TeeSegment(const char *buf, PRUint32 count);
static NS_METHOD WriteSegmentFun(nsIInputStream *, void *, const char *,
PRUint32, PRUint32, PRUint32 *);
private:
nsCOMPtr<nsIInputStream> mSource;
nsCOMPtr<nsIOutputStream> mSink;
nsCOMPtr<nsIEventTarget> mEventTarget;
nsWriteSegmentFun mWriter; // for implementing ReadSegments
void *mClosure; // for implementing ReadSegments
nsAutoPtr<Mutex> mLock; // synchronize access to mSinkIsValid
bool mSinkIsValid; // False if TeeWriteEvent fails
};
class nsInputStreamTeeWriteEvent : public nsRunnable {
public:
// aTee's lock is held across construction of this object
nsInputStreamTeeWriteEvent(const char *aBuf, PRUint32 aCount,
nsIOutputStream *aSink,
nsInputStreamTee *aTee)
{
// copy the buffer - will be free'd by dtor
mBuf = (char *)malloc(aCount);
if (mBuf) memcpy(mBuf, (char *)aBuf, aCount);
mCount = aCount;
mSink = aSink;
bool isNonBlocking;
mSink->IsNonBlocking(&isNonBlocking);
NS_ASSERTION(isNonBlocking == false, "mSink is nonblocking");
mTee = aTee;
}
NS_IMETHOD Run()
{
if (!mBuf) {
NS_WARNING("nsInputStreamTeeWriteEvent::Run() "
"memory not allocated\n");
return NS_OK;
}
NS_ABORT_IF_FALSE(mSink, "mSink is null!");
// The output stream could have been invalidated between when
// this event was dispatched and now, so check before writing.
if (!mTee->SinkIsValid()) {
return NS_OK;
}
LOG(("nsInputStreamTeeWriteEvent::Run() [%p]"
"will write %u bytes to %p\n",
this, mCount, mSink.get()));
PRUint32 totalBytesWritten = 0;
while (mCount) {
nsresult rv;
PRUint32 bytesWritten = 0;
rv = mSink->Write(mBuf + totalBytesWritten, mCount, &bytesWritten);
if (NS_FAILED(rv)) {
LOG(("nsInputStreamTeeWriteEvent::Run[%p] error %x in writing",
this,rv));
mTee->InvalidateSink();
break;
}
totalBytesWritten += bytesWritten;
NS_ASSERTION(bytesWritten <= mCount, "wrote too much");
mCount -= bytesWritten;
}
return NS_OK;
}
protected:
virtual ~nsInputStreamTeeWriteEvent()
{
if (mBuf) free(mBuf);
mBuf = nsnull;
}
private:
char *mBuf;
PRUint32 mCount;
nsCOMPtr<nsIOutputStream> mSink;
// back pointer to the tee that created this runnable
nsRefPtr<nsInputStreamTee> mTee;
};
nsInputStreamTee::nsInputStreamTee(): mLock(nsnull)
, mSinkIsValid(true)
{
}
bool
nsInputStreamTee::SinkIsValid()
{
MutexAutoLock lock(*mLock);
return mSinkIsValid;
}
void
nsInputStreamTee::InvalidateSink()
{
MutexAutoLock lock(*mLock);
mSinkIsValid = false;
}
nsresult
nsInputStreamTee::TeeSegment(const char *buf, PRUint32 count)
{
if (!mSink) return NS_OK; // nothing to do
if (mLock) { // asynchronous case
NS_ASSERTION(mEventTarget, "mEventTarget is null, mLock is not null.");
if (!SinkIsValid()) {
return NS_OK; // nothing to do
}
nsRefPtr<nsIRunnable> event =
new nsInputStreamTeeWriteEvent(buf, count, mSink, this);
NS_ENSURE_TRUE(event, NS_ERROR_OUT_OF_MEMORY);
LOG(("nsInputStreamTee::TeeSegment [%p] dispatching write %u bytes\n",
this, count));
return mEventTarget->Dispatch(event, NS_DISPATCH_NORMAL);
} else { // synchronous case
NS_ASSERTION(!mEventTarget, "mEventTarget is not null, mLock is null.");
nsresult rv;
PRUint32 totalBytesWritten = 0;
while (count) {
PRUint32 bytesWritten = 0;
rv = mSink->Write(buf + totalBytesWritten, count, &bytesWritten);
if (NS_FAILED(rv)) {
// ok, this is not a fatal error... just drop our reference to mSink
// and continue on as if nothing happened.
NS_WARNING("Write failed (non-fatal)");
// catch possible misuse of the input stream tee
NS_ASSERTION(rv != NS_BASE_STREAM_WOULD_BLOCK, "sink must be a blocking stream");
mSink = 0;
break;
}
totalBytesWritten += bytesWritten;
NS_ASSERTION(bytesWritten <= count, "wrote too much");
count -= bytesWritten;
}
return NS_OK;
}
}
NS_METHOD
nsInputStreamTee::WriteSegmentFun(nsIInputStream *in, void *closure, const char *fromSegment,
PRUint32 offset, PRUint32 count, PRUint32 *writeCount)
{
nsInputStreamTee *tee = reinterpret_cast<nsInputStreamTee *>(closure);
nsresult rv = tee->mWriter(in, tee->mClosure, fromSegment, offset, count, writeCount);
if (NS_FAILED(rv) || (*writeCount == 0)) {
NS_ASSERTION((NS_FAILED(rv) ? (*writeCount == 0) : true),
"writer returned an error with non-zero writeCount");
return rv;
}
return tee->TeeSegment(fromSegment, *writeCount);
}
NS_IMPL_THREADSAFE_ISUPPORTS2(nsInputStreamTee,
nsIInputStreamTee,
nsIInputStream)
NS_IMETHODIMP
nsInputStreamTee::Close()
{
NS_ENSURE_TRUE(mSource, NS_ERROR_NOT_INITIALIZED);
nsresult rv = mSource->Close();
mSource = 0;
mSink = 0;
return rv;
}
NS_IMETHODIMP
nsInputStreamTee::Available(PRUint32 *avail)
{
NS_ENSURE_TRUE(mSource, NS_ERROR_NOT_INITIALIZED);
return mSource->Available(avail);
}
NS_IMETHODIMP
nsInputStreamTee::Read(char *buf, PRUint32 count, PRUint32 *bytesRead)
{
NS_ENSURE_TRUE(mSource, NS_ERROR_NOT_INITIALIZED);
nsresult rv = mSource->Read(buf, count, bytesRead);
if (NS_FAILED(rv) || (*bytesRead == 0))
return rv;
return TeeSegment(buf, *bytesRead);
}
NS_IMETHODIMP
nsInputStreamTee::ReadSegments(nsWriteSegmentFun writer,
void *closure,
PRUint32 count,
PRUint32 *bytesRead)
{
NS_ENSURE_TRUE(mSource, NS_ERROR_NOT_INITIALIZED);
mWriter = writer;
mClosure = closure;
return mSource->ReadSegments(WriteSegmentFun, this, count, bytesRead);
}
NS_IMETHODIMP
nsInputStreamTee::IsNonBlocking(bool *result)
{
NS_ENSURE_TRUE(mSource, NS_ERROR_NOT_INITIALIZED);
return mSource->IsNonBlocking(result);
}
NS_IMETHODIMP
nsInputStreamTee::SetSource(nsIInputStream *source)
{
mSource = source;
return NS_OK;
}
NS_IMETHODIMP
nsInputStreamTee::GetSource(nsIInputStream **source)
{
NS_IF_ADDREF(*source = mSource);
return NS_OK;
}
NS_IMETHODIMP
nsInputStreamTee::SetSink(nsIOutputStream *sink)
{
#ifdef DEBUG
if (sink) {
bool nonBlocking;
nsresult rv = sink->IsNonBlocking(&nonBlocking);
if (NS_FAILED(rv) || nonBlocking)
NS_ERROR("sink should be a blocking stream");
}
#endif
mSink = sink;
return NS_OK;
}
NS_IMETHODIMP
nsInputStreamTee::GetSink(nsIOutputStream **sink)
{
NS_IF_ADDREF(*sink = mSink);
return NS_OK;
}
NS_IMETHODIMP
nsInputStreamTee::SetEventTarget(nsIEventTarget *anEventTarget)
{
mEventTarget = anEventTarget;
if (mEventTarget) {
// Only need synchronization if this is an async tee
mLock = new Mutex("nsInputStreamTee.mLock");
}
return NS_OK;
}
NS_IMETHODIMP
nsInputStreamTee::GetEventTarget(nsIEventTarget **anEventTarget)
{
NS_IF_ADDREF(*anEventTarget = mEventTarget);
return NS_OK;
}
nsresult
NS_NewInputStreamTeeAsync(nsIInputStream **result,
nsIInputStream *source,
nsIOutputStream *sink,
nsIEventTarget *anEventTarget)
{
nsresult rv;
nsCOMPtr<nsIInputStreamTee> tee = new nsInputStreamTee();
if (!tee)
return NS_ERROR_OUT_OF_MEMORY;
rv = tee->SetSource(source);
if (NS_FAILED(rv)) return rv;
rv = tee->SetSink(sink);
if (NS_FAILED(rv)) return rv;
rv = tee->SetEventTarget(anEventTarget);
if (NS_FAILED(rv)) return rv;
NS_ADDREF(*result = tee);
return rv;
}
nsresult
NS_NewInputStreamTee(nsIInputStream **result,
nsIInputStream *source,
nsIOutputStream *sink)
{
return NS_NewInputStreamTeeAsync(result, source, sink, nsnull);
}