gecko/xpcom/io/nsMultiplexInputStream.cpp

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/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
2012-05-21 04:12:37 -07:00
/* 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 "mozilla/Attributes.h"
#include "mozilla/MathAlgorithms.h"
#include "base/basictypes.h"
#include "nsMultiplexInputStream.h"
#include "nsIMultiplexInputStream.h"
#include "nsISeekableStream.h"
#include "nsCOMPtr.h"
#include "nsCOMArray.h"
#include "nsIClassInfoImpl.h"
#include "nsIIPCSerializableInputStream.h"
#include "mozilla/ipc/InputStreamUtils.h"
using namespace mozilla::ipc;
using mozilla::DeprecatedAbs;
class nsMultiplexInputStream MOZ_FINAL : public nsIMultiplexInputStream,
public nsISeekableStream,
public nsIIPCSerializableInputStream
{
public:
nsMultiplexInputStream();
NS_DECL_ISUPPORTS
NS_DECL_NSIINPUTSTREAM
NS_DECL_NSIMULTIPLEXINPUTSTREAM
NS_DECL_NSISEEKABLESTREAM
NS_DECL_NSIIPCSERIALIZABLEINPUTSTREAM
private:
~nsMultiplexInputStream() {}
struct ReadSegmentsState {
nsIInputStream* mThisStream;
uint32_t mOffset;
nsWriteSegmentFun mWriter;
void* mClosure;
bool mDone;
};
static NS_METHOD ReadSegCb(nsIInputStream* aIn, void* aClosure,
const char* aFromRawSegment, uint32_t aToOffset,
uint32_t aCount, uint32_t *aWriteCount);
nsTArray<nsCOMPtr<nsIInputStream> > mStreams;
uint32_t 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,
nsIIPCSerializableInputStream)
NS_IMPL_CI_INTERFACE_GETTER3(nsMultiplexInputStream,
nsIMultiplexInputStream,
nsIInputStream,
nsISeekableStream)
nsMultiplexInputStream::nsMultiplexInputStream()
: mCurrentStream(0),
mStartedReadingCurrent(false),
mStatus(NS_OK)
{
}
/* readonly attribute unsigned long count; */
NS_IMETHODIMP
nsMultiplexInputStream::GetCount(uint32_t *aCount)
{
*aCount = mStreams.Length();
return NS_OK;
}
#ifdef DEBUG
static bool
SeekableStreamAtBeginning(nsIInputStream *aStream)
{
int64_t streamPos;
nsCOMPtr<nsISeekableStream> stream = do_QueryInterface(aStream);
if (stream && NS_SUCCEEDED(stream->Tell(&streamPos)) && streamPos != 0) {
return false;
}
return true;
}
#endif
/* void appendStream (in nsIInputStream stream); */
NS_IMETHODIMP
nsMultiplexInputStream::AppendStream(nsIInputStream *aStream)
{
NS_ASSERTION(SeekableStreamAtBeginning(aStream), "Appended stream not at beginning.");
return mStreams.AppendElement(aStream) ? NS_OK : NS_ERROR_OUT_OF_MEMORY;
}
/* void insertStream (in nsIInputStream stream, in unsigned long index); */
NS_IMETHODIMP
nsMultiplexInputStream::InsertStream(nsIInputStream *aStream, uint32_t aIndex)
{
NS_ASSERTION(SeekableStreamAtBeginning(aStream), "Inserted stream not at beginning.");
bool result = mStreams.InsertElementAt(aIndex, aStream);
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(uint32_t aIndex)
{
mStreams.RemoveElementAt(aIndex);
if (mCurrentStream > aIndex)
--mCurrentStream;
else if (mCurrentStream == aIndex)
mStartedReadingCurrent = false;
return NS_OK;
}
/* nsIInputStream getStream (in unsigned long index); */
NS_IMETHODIMP
nsMultiplexInputStream::GetStream(uint32_t aIndex, nsIInputStream **_retval)
{
*_retval = mStreams.SafeElementAt(aIndex, nullptr);
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;
uint32_t len = mStreams.Length();
for (uint32_t 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 long available (); */
NS_IMETHODIMP
nsMultiplexInputStream::Available(uint64_t *_retval)
{
if (NS_FAILED(mStatus))
return mStatus;
nsresult rv;
uint64_t avail = 0;
uint32_t len = mStreams.Length();
for (uint32_t i = mCurrentStream; i < len; i++) {
uint64_t 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, uint32_t aCount, uint32_t *_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;
uint32_t len = mStreams.Length();
while (mCurrentStream < len && aCount) {
uint32_t 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,
uint32_t aCount, uint32_t *_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;
uint32_t len = mStreams.Length();
while (mCurrentStream < len && aCount) {
uint32_t 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,
uint32_t aToOffset, uint32_t aCount,
uint32_t *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)
{
uint32_t len = mStreams.Length();
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 (uint32_t 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 int32_t whence, in int32_t offset); */
NS_IMETHODIMP
nsMultiplexInputStream::Seek(int32_t aWhence, int64_t aOffset)
{
if (NS_FAILED(mStatus))
return mStatus;
nsresult rv;
uint32_t oldCurrentStream = mCurrentStream;
bool oldStartedReadingCurrent = mStartedReadingCurrent;
if (aWhence == NS_SEEK_SET) {
int64_t remaining = aOffset;
if (aOffset == 0) {
mCurrentStream = 0;
}
for (uint32_t i = 0; i < mStreams.Length(); ++i) {
nsCOMPtr<nsISeekableStream> stream =
do_QueryInterface(mStreams[i]);
if (!stream) {
return NS_ERROR_FAILURE;
}
// See if all remaining streams should be rewound
if (remaining == 0) {
if (i < oldCurrentStream ||
(i == oldCurrentStream && oldStartedReadingCurrent)) {
rv = stream->Seek(NS_SEEK_SET, 0);
NS_ENSURE_SUCCESS(rv, rv);
continue;
}
else {
break;
}
}
// Get position in current stream
int64_t streamPos;
if (i > oldCurrentStream ||
(i == oldCurrentStream && !oldStartedReadingCurrent)) {
streamPos = 0;
}
else {
rv = stream->Tell(&streamPos);
NS_ENSURE_SUCCESS(rv, rv);
}
// See if we need to seek current stream forward or backward
if (remaining < streamPos) {
rv = stream->Seek(NS_SEEK_SET, remaining);
NS_ENSURE_SUCCESS(rv, rv);
mCurrentStream = i;
mStartedReadingCurrent = remaining != 0;
remaining = 0;
}
else if (remaining > streamPos) {
if (i < oldCurrentStream) {
// We're already at end so no need to seek this stream
remaining -= streamPos;
NS_ASSERTION(remaining >= 0, "Remaining invalid");
}
else {
uint64_t avail;
rv = mStreams[i]->Available(&avail);
NS_ENSURE_SUCCESS(rv, rv);
int64_t newPos = XPCOM_MIN(remaining, streamPos + (int64_t)avail);
rv = stream->Seek(NS_SEEK_SET, newPos);
NS_ENSURE_SUCCESS(rv, rv);
mCurrentStream = i;
mStartedReadingCurrent = true;
remaining -= newPos;
NS_ASSERTION(remaining >= 0, "Remaining invalid");
}
}
else {
NS_ASSERTION(remaining == streamPos, "Huh?");
remaining = 0;
}
}
return NS_OK;
}
if (aWhence == NS_SEEK_CUR && aOffset > 0) {
int64_t remaining = aOffset;
for (uint32_t i = mCurrentStream; remaining && i < mStreams.Length(); ++i) {
nsCOMPtr<nsISeekableStream> stream =
do_QueryInterface(mStreams[i]);
uint64_t avail;
rv = mStreams[i]->Available(&avail);
NS_ENSURE_SUCCESS(rv, rv);
int64_t seek = XPCOM_MIN((int64_t)avail, remaining);
rv = stream->Seek(NS_SEEK_CUR, seek);
NS_ENSURE_SUCCESS(rv, rv);
mCurrentStream = i;
mStartedReadingCurrent = true;
remaining -= seek;
}
return NS_OK;
}
if (aWhence == NS_SEEK_CUR && aOffset < 0) {
int64_t remaining = -aOffset;
for (uint32_t i = mCurrentStream; remaining && i != (uint32_t)-1; --i) {
nsCOMPtr<nsISeekableStream> stream =
do_QueryInterface(mStreams[i]);
int64_t pos;
rv = stream->Tell(&pos);
NS_ENSURE_SUCCESS(rv, rv);
int64_t seek = XPCOM_MIN(pos, remaining);
rv = stream->Seek(NS_SEEK_CUR, -seek);
NS_ENSURE_SUCCESS(rv, rv);
mCurrentStream = i;
mStartedReadingCurrent = seek != -pos;
remaining -= seek;
}
return NS_OK;
}
if (aWhence == NS_SEEK_CUR) {
NS_ASSERTION(aOffset == 0, "Should have handled all non-zero values");
return NS_OK;
}
if (aWhence == NS_SEEK_END) {
if (aOffset > 0) {
return NS_ERROR_INVALID_ARG;
}
int64_t remaining = aOffset;
for (uint32_t i = mStreams.Length() - 1; i != (uint32_t)-1; --i) {
nsCOMPtr<nsISeekableStream> stream =
do_QueryInterface(mStreams[i]);
// See if all remaining streams should be seeked to end
if (remaining == 0) {
if (i >= oldCurrentStream) {
rv = stream->Seek(NS_SEEK_END, 0);
NS_ENSURE_SUCCESS(rv, rv);
}
else {
break;
}
}
// Get position in current stream
int64_t streamPos;
if (i < oldCurrentStream) {
streamPos = 0;
} else {
uint64_t avail;
rv = mStreams[i]->Available(&avail);
NS_ENSURE_SUCCESS(rv, rv);
streamPos = avail;
}
// See if we have enough data in the current stream.
if (DeprecatedAbs(remaining) < streamPos) {
rv = stream->Seek(NS_SEEK_END, remaining);
NS_ENSURE_SUCCESS(rv, rv);
mCurrentStream = i;
mStartedReadingCurrent = true;
remaining = 0;
} else if (DeprecatedAbs(remaining) > streamPos) {
if (i > oldCurrentStream ||
(i == oldCurrentStream && !oldStartedReadingCurrent)) {
// We're already at start so no need to seek this stream
remaining += streamPos;
} else {
int64_t avail;
rv = stream->Tell(&avail);
NS_ENSURE_SUCCESS(rv, rv);
int64_t newPos = streamPos + XPCOM_MIN(avail, DeprecatedAbs(remaining));
rv = stream->Seek(NS_SEEK_END, -newPos);
NS_ENSURE_SUCCESS(rv, rv);
mCurrentStream = i;
mStartedReadingCurrent = true;
remaining += newPos;
}
}
else {
NS_ASSERTION(remaining == streamPos, "Huh?");
remaining = 0;
}
}
return NS_OK;
}
// other Seeks not implemented yet
return NS_ERROR_NOT_IMPLEMENTED;
}
/* uint32_t tell (); */
NS_IMETHODIMP
nsMultiplexInputStream::Tell(int64_t *_retval)
{
if (NS_FAILED(mStatus))
return mStatus;
nsresult rv;
int64_t ret64 = 0;
uint32_t 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);
int64_t 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 = nullptr;
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;
}
void
nsMultiplexInputStream::Serialize(InputStreamParams& aParams)
{
MultiplexInputStreamParams params;
uint32_t streamCount = mStreams.Length();
if (streamCount) {
InfallibleTArray<InputStreamParams>& streams = params.streams();
streams.SetCapacity(streamCount);
for (uint32_t index = 0; index < streamCount; index++) {
nsCOMPtr<nsIIPCSerializableInputStream> serializable =
do_QueryInterface(mStreams[index]);
NS_ASSERTION(serializable, "Child stream isn't serializable!");
if (serializable) {
InputStreamParams childStreamParams;
serializable->Serialize(childStreamParams);
NS_ASSERTION(childStreamParams.type() !=
InputStreamParams::T__None,
"Serialize failed!");
streams.AppendElement(childStreamParams);
}
}
}
params.currentStream() = mCurrentStream;
params.status() = mStatus;
params.startedReadingCurrent() = mStartedReadingCurrent;
aParams = params;
}
bool
nsMultiplexInputStream::Deserialize(const InputStreamParams& aParams)
{
if (aParams.type() !=
InputStreamParams::TMultiplexInputStreamParams) {
NS_ERROR("Received unknown parameters from the other process!");
return false;
}
const MultiplexInputStreamParams& params =
aParams.get_MultiplexInputStreamParams();
const InfallibleTArray<InputStreamParams>& streams = params.streams();
uint32_t streamCount = streams.Length();
for (uint32_t index = 0; index < streamCount; index++) {
nsCOMPtr<nsIInputStream> stream =
DeserializeInputStream(streams[index]);
if (!stream) {
NS_WARNING("Deserialize failed!");
return false;
}
if (NS_FAILED(AppendStream(stream))) {
NS_WARNING("AppendStream failed!");
return false;
}
}
mCurrentStream = params.currentStream();
mStatus = params.status();
mStartedReadingCurrent = params.startedReadingCurrent();
return true;
}