xpcom/io/nsMultiplexInputStream.cpp

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b8e299dddd091ae24e0c08c45d91b8f937bd14d2vboxsync * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
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b8e299dddd091ae24e0c08c45d91b8f937bd14d2vboxsync *
b8e299dddd091ae24e0c08c45d91b8f937bd14d2vboxsync * The Original Code is frightening to behold.
b8e299dddd091ae24e0c08c45d91b8f937bd14d2vboxsync *
b8e299dddd091ae24e0c08c45d91b8f937bd14d2vboxsync * The Initial Developer of the Original Code is
b8e299dddd091ae24e0c08c45d91b8f937bd14d2vboxsync * Jonas Sicking.
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b8e299dddd091ae24e0c08c45d91b8f937bd14d2vboxsync * the Initial Developer. All Rights Reserved.
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b8e299dddd091ae24e0c08c45d91b8f937bd14d2vboxsync * Contributor(s):
b8e299dddd091ae24e0c08c45d91b8f937bd14d2vboxsync *   Jonas Sicking <sicking@bigfoot.com>
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b8e299dddd091ae24e0c08c45d91b8f937bd14d2vboxsync
b8e299dddd091ae24e0c08c45d91b8f937bd14d2vboxsync/**
b8e299dddd091ae24e0c08c45d91b8f937bd14d2vboxsync * The multiplex stream concatenates a list of input streams into a single
b8e299dddd091ae24e0c08c45d91b8f937bd14d2vboxsync * stream.
b8e299dddd091ae24e0c08c45d91b8f937bd14d2vboxsync */
b8e299dddd091ae24e0c08c45d91b8f937bd14d2vboxsync
b8e299dddd091ae24e0c08c45d91b8f937bd14d2vboxsync#include "nsMultiplexInputStream.h"
b8e299dddd091ae24e0c08c45d91b8f937bd14d2vboxsync#include "nsIMultiplexInputStream.h"
b8e299dddd091ae24e0c08c45d91b8f937bd14d2vboxsync#include "nsISeekableStream.h"
b8e299dddd091ae24e0c08c45d91b8f937bd14d2vboxsync#include "nsSupportsArray.h"
b8e299dddd091ae24e0c08c45d91b8f937bd14d2vboxsync#include "nsInt64.h"
b8e299dddd091ae24e0c08c45d91b8f937bd14d2vboxsync
b8e299dddd091ae24e0c08c45d91b8f937bd14d2vboxsyncclass nsMultiplexInputStream : public nsIMultiplexInputStream,
b8e299dddd091ae24e0c08c45d91b8f937bd14d2vboxsync                               public nsISeekableStream
b8e299dddd091ae24e0c08c45d91b8f937bd14d2vboxsync{
b8e299dddd091ae24e0c08c45d91b8f937bd14d2vboxsyncpublic:
b8e299dddd091ae24e0c08c45d91b8f937bd14d2vboxsync    nsMultiplexInputStream();
b8e299dddd091ae24e0c08c45d91b8f937bd14d2vboxsync
b8e299dddd091ae24e0c08c45d91b8f937bd14d2vboxsync    NS_DECL_ISUPPORTS
b8e299dddd091ae24e0c08c45d91b8f937bd14d2vboxsync    NS_DECL_NSIINPUTSTREAM
b8e299dddd091ae24e0c08c45d91b8f937bd14d2vboxsync    NS_DECL_NSIMULTIPLEXINPUTSTREAM
b8e299dddd091ae24e0c08c45d91b8f937bd14d2vboxsync    NS_DECL_NSISEEKABLESTREAM
b8e299dddd091ae24e0c08c45d91b8f937bd14d2vboxsync
b8e299dddd091ae24e0c08c45d91b8f937bd14d2vboxsync    static NS_METHOD Create(nsISupports *outer, REFNSIID iid, void **result);
b8e299dddd091ae24e0c08c45d91b8f937bd14d2vboxsync
b8e299dddd091ae24e0c08c45d91b8f937bd14d2vboxsyncprivate:
b8e299dddd091ae24e0c08c45d91b8f937bd14d2vboxsync    ~nsMultiplexInputStream() {}
b8e299dddd091ae24e0c08c45d91b8f937bd14d2vboxsync
b8e299dddd091ae24e0c08c45d91b8f937bd14d2vboxsync
b8e299dddd091ae24e0c08c45d91b8f937bd14d2vboxsync    struct ReadSegmentsState {
b8e299dddd091ae24e0c08c45d91b8f937bd14d2vboxsync        nsIInputStream* mThisStream;
b8e299dddd091ae24e0c08c45d91b8f937bd14d2vboxsync        PRUint32 mOffset;
b8e299dddd091ae24e0c08c45d91b8f937bd14d2vboxsync        nsWriteSegmentFun mWriter;
b8e299dddd091ae24e0c08c45d91b8f937bd14d2vboxsync        void* mClosure;
b8e299dddd091ae24e0c08c45d91b8f937bd14d2vboxsync        PRBool mDone;
b8e299dddd091ae24e0c08c45d91b8f937bd14d2vboxsync    };
b8e299dddd091ae24e0c08c45d91b8f937bd14d2vboxsync
b8e299dddd091ae24e0c08c45d91b8f937bd14d2vboxsync    static NS_METHOD ReadSegCb(nsIInputStream* aIn, void* aClosure,
b8e299dddd091ae24e0c08c45d91b8f937bd14d2vboxsync                               const char* aFromRawSegment, PRUint32 aToOffset,
b8e299dddd091ae24e0c08c45d91b8f937bd14d2vboxsync                               PRUint32 aCount, PRUint32 *aWriteCount);
b8e299dddd091ae24e0c08c45d91b8f937bd14d2vboxsync
b8e299dddd091ae24e0c08c45d91b8f937bd14d2vboxsync    nsSupportsArray mStreams;
b8e299dddd091ae24e0c08c45d91b8f937bd14d2vboxsync    PRUint32 mCurrentStream;
b8e299dddd091ae24e0c08c45d91b8f937bd14d2vboxsync    PRBool mStartedReadingCurrent;
b8e299dddd091ae24e0c08c45d91b8f937bd14d2vboxsync};
b8e299dddd091ae24e0c08c45d91b8f937bd14d2vboxsync
b8e299dddd091ae24e0c08c45d91b8f937bd14d2vboxsync
b8e299dddd091ae24e0c08c45d91b8f937bd14d2vboxsyncNS_IMPL_THREADSAFE_ISUPPORTS3(nsMultiplexInputStream,
b8e299dddd091ae24e0c08c45d91b8f937bd14d2vboxsync                              nsIMultiplexInputStream,
b8e299dddd091ae24e0c08c45d91b8f937bd14d2vboxsync                              nsIInputStream,
b8e299dddd091ae24e0c08c45d91b8f937bd14d2vboxsync                              nsISeekableStream)
b8e299dddd091ae24e0c08c45d91b8f937bd14d2vboxsync
b8e299dddd091ae24e0c08c45d91b8f937bd14d2vboxsyncnsMultiplexInputStream::nsMultiplexInputStream()
b8e299dddd091ae24e0c08c45d91b8f937bd14d2vboxsync    : mCurrentStream(0),
b8e299dddd091ae24e0c08c45d91b8f937bd14d2vboxsync      mStartedReadingCurrent(PR_FALSE)
b8e299dddd091ae24e0c08c45d91b8f937bd14d2vboxsync{
b8e299dddd091ae24e0c08c45d91b8f937bd14d2vboxsync}
b8e299dddd091ae24e0c08c45d91b8f937bd14d2vboxsync
b8e299dddd091ae24e0c08c45d91b8f937bd14d2vboxsync/* readonly attribute unsigned long count; */
b8e299dddd091ae24e0c08c45d91b8f937bd14d2vboxsyncNS_IMETHODIMP
b8e299dddd091ae24e0c08c45d91b8f937bd14d2vboxsyncnsMultiplexInputStream::GetCount(PRUint32 *aCount)
b8e299dddd091ae24e0c08c45d91b8f937bd14d2vboxsync{
b8e299dddd091ae24e0c08c45d91b8f937bd14d2vboxsync    mStreams.Count(aCount);
b8e299dddd091ae24e0c08c45d91b8f937bd14d2vboxsync    return NS_OK;
b8e299dddd091ae24e0c08c45d91b8f937bd14d2vboxsync}
b8e299dddd091ae24e0c08c45d91b8f937bd14d2vboxsync
b8e299dddd091ae24e0c08c45d91b8f937bd14d2vboxsync/* void appendStream (in nsIInputStream stream); */
b8e299dddd091ae24e0c08c45d91b8f937bd14d2vboxsyncNS_IMETHODIMP
b8e299dddd091ae24e0c08c45d91b8f937bd14d2vboxsyncnsMultiplexInputStream::AppendStream(nsIInputStream *aStream)
b8e299dddd091ae24e0c08c45d91b8f937bd14d2vboxsync{
b8e299dddd091ae24e0c08c45d91b8f937bd14d2vboxsync    return mStreams.AppendElement(aStream);
b8e299dddd091ae24e0c08c45d91b8f937bd14d2vboxsync}
b8e299dddd091ae24e0c08c45d91b8f937bd14d2vboxsync
b8e299dddd091ae24e0c08c45d91b8f937bd14d2vboxsync/* void insertStream (in nsIInputStream stream, in unsigned long index); */
b8e299dddd091ae24e0c08c45d91b8f937bd14d2vboxsyncNS_IMETHODIMP
b8e299dddd091ae24e0c08c45d91b8f937bd14d2vboxsyncnsMultiplexInputStream::InsertStream(nsIInputStream *aStream, PRUint32 aIndex)
b8e299dddd091ae24e0c08c45d91b8f937bd14d2vboxsync{
b8e299dddd091ae24e0c08c45d91b8f937bd14d2vboxsync    nsresult rv = mStreams.InsertElementAt(aStream, aIndex);
b8e299dddd091ae24e0c08c45d91b8f937bd14d2vboxsync    NS_ENSURE_SUCCESS(rv, rv);
b8e299dddd091ae24e0c08c45d91b8f937bd14d2vboxsync    if (mCurrentStream > aIndex ||
b8e299dddd091ae24e0c08c45d91b8f937bd14d2vboxsync        (mCurrentStream == aIndex && mStartedReadingCurrent))
b8e299dddd091ae24e0c08c45d91b8f937bd14d2vboxsync        ++mCurrentStream;
b8e299dddd091ae24e0c08c45d91b8f937bd14d2vboxsync    return rv;
b8e299dddd091ae24e0c08c45d91b8f937bd14d2vboxsync}
b8e299dddd091ae24e0c08c45d91b8f937bd14d2vboxsync
b8e299dddd091ae24e0c08c45d91b8f937bd14d2vboxsync/* void removeStream (in unsigned long index); */
b8e299dddd091ae24e0c08c45d91b8f937bd14d2vboxsyncNS_IMETHODIMP
nsMultiplexInputStream::RemoveStream(PRUint32 aIndex)
{
    nsresult rv = mStreams.RemoveElementAt(aIndex);
    NS_ENSURE_SUCCESS(rv, rv);
    if (mCurrentStream > aIndex)
        --mCurrentStream;
    else if (mCurrentStream == aIndex)
        mStartedReadingCurrent = PR_FALSE;

    return rv;
}

/* nsIInputStream getStream (in unsigned long index); */
NS_IMETHODIMP
nsMultiplexInputStream::GetStream(PRUint32 aIndex, nsIInputStream **_retval)
{
    return mStreams.QueryElementAt(aIndex,
                                   NS_GET_IID(nsIInputStream),
                                   (void**)_retval);
}

/* void close (); */
NS_IMETHODIMP
nsMultiplexInputStream::Close()
{
    PRUint32 len, i;
    nsresult rv = NS_OK;

    mStreams.Count(&len);
    for (i = 0; i < len; ++i) {
        nsCOMPtr<nsIInputStream> stream(do_QueryElementAt(&mStreams, i));
        nsresult rv2 = stream->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)
{
    nsresult rv;
    PRUint32 i, len, avail = 0;

    mStreams.Count(&len);
    for (i = mCurrentStream; i < len; i++) {
        nsCOMPtr<nsIInputStream> stream(do_QueryElementAt(&mStreams, i));

        PRUint32 streamAvail;
        rv = stream->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)
{
    nsresult rv = NS_OK;
    PRUint32 len, read;

    *_retval = 0;

    mStreams.Count(&len);
    while (mCurrentStream < len && aCount) {
        nsCOMPtr<nsIInputStream> stream(do_QueryElementAt(&mStreams,
                                                          mCurrentStream));
        rv = stream->Read(aBuf, aCount, &read);

        // XXX some streams return NS_BASE_STREAM_CLOSED to indicate EOF.
        if (rv == 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)
{
    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(&len);
    while (mCurrentStream < len && aCount) {
        nsCOMPtr<nsIInputStream> stream(do_QueryElementAt(&mStreams,
                                                          mCurrentStream));
        PRUint32 read;
        rv = stream->ReadSegments(ReadSegCb, &state, aCount, &read);

        // XXX some streams return NS_BASE_STREAM_CLOSED to indicate EOF.
        if (rv == 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)
{
    nsresult rv;
    PRUint32 i, len;

    mStreams.Count(&len);
    for (i = 0; i < len; ++i) {
        nsCOMPtr<nsIInputStream> stream(do_QueryElementAt(&mStreams, i));
        rv = stream->IsNonBlocking(aNonBlocking);
        NS_ENSURE_SUCCESS(rv, rv);
        // If one is non-blocking the entire stream becomes non-blocking
        if (*aNonBlocking)
            return NS_OK;
    }
    return NS_OK;
}

/* void seek (in PRInt32 whence, in PRInt32 offset); */
NS_IMETHODIMP
nsMultiplexInputStream::Seek(PRInt32 aWhence, PRInt64 aOffset)
{
    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_QueryElementAt(&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)
{
    nsresult rv;
    nsInt64 ret64 = 0;
    PRUint32 i, last;
    last = mStartedReadingCurrent ? mCurrentStream+1 : mCurrentStream;
    for (i = 0; i < last; ++i) {
        nsCOMPtr<nsISeekableStream> stream(do_QueryElementAt(&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;
}