gecko/xpcom/io/nsMultiplexInputStream.cpp
2014-05-14 23:15:46 +03:00

761 lines
20 KiB
C++

/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* 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_THREADSAFE_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_ADDREF(nsMultiplexInputStream)
NS_IMPL_RELEASE(nsMultiplexInputStream)
NS_IMPL_CLASSINFO(nsMultiplexInputStream, nullptr, nsIClassInfo::THREADSAFE,
NS_MULTIPLEXINPUTSTREAM_CID)
NS_IMPL_QUERY_INTERFACE_CI(nsMultiplexInputStream,
nsIMultiplexInputStream,
nsIInputStream,
nsISeekableStream,
nsIIPCSerializableInputStream)
NS_IMPL_CI_INTERFACE_GETTER(nsMultiplexInputStream,
nsIMultiplexInputStream,
nsIInputStream,
nsISeekableStream)
static nsresult
AvailableMaybeSeek(nsIInputStream* aStream, uint64_t* aResult)
{
nsresult rv = aStream->Available(aResult);
if (rv == NS_BASE_STREAM_CLOSED) {
// Blindly seek to the current position if Available() returns
// NS_BASE_STREAM_CLOSED.
// If nsIFileInputStream is closed in Read() due to CLOSE_ON_EOF flag,
// Seek() could reopen the file if REOPEN_ON_REWIND flag is set.
nsCOMPtr<nsISeekableStream> seekable = do_QueryInterface(aStream);
if (seekable) {
nsresult rv = seekable->Seek(nsISeekableStream::NS_SEEK_CUR, 0);
if (NS_SUCCEEDED(rv)) {
rv = aStream->Available(aResult);
}
}
}
return rv;
}
static nsresult
TellMaybeSeek(nsISeekableStream* aSeekable, int64_t* aResult)
{
nsresult rv = aSeekable->Tell(aResult);
if (rv == NS_BASE_STREAM_CLOSED) {
// Blindly seek to the current position if Tell() returns
// NS_BASE_STREAM_CLOSED.
// If nsIFileInputStream is closed in Read() due to CLOSE_ON_EOF flag,
// Seek() could reopen the file if REOPEN_ON_REWIND flag is set.
nsresult rv = aSeekable->Seek(nsISeekableStream::NS_SEEK_CUR, 0);
if (NS_SUCCEEDED(rv)) {
rv = aSeekable->Tell(aResult);
}
}
return rv;
}
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.");
mStreams.InsertElementAt(aIndex, aStream);
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** aResult)
{
*aResult = mStreams.SafeElementAt(aIndex, nullptr);
if (NS_WARN_IF(!*aResult)) {
return NS_ERROR_NOT_AVAILABLE;
}
NS_ADDREF(*aResult);
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* aResult)
{
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 = AvailableMaybeSeek(mStreams[i], &streamAvail);
if (NS_WARN_IF(NS_FAILED(rv))) {
return rv;
}
avail += streamAvail;
}
*aResult = 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* aResult)
{
// 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).
*aResult = 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");
*aResult += read;
aCount -= read;
aBuf += read;
mStartedReadingCurrent = true;
}
}
return *aResult ? 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* aResult)
{
if (mStatus == NS_BASE_STREAM_CLOSED) {
*aResult = 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.
*aResult = 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);
if (NS_WARN_IF(NS_FAILED(rv))) {
return 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);
if (NS_WARN_IF(NS_FAILED(rv))) {
return rv;
}
continue;
} else {
break;
}
}
// Get position in current stream
int64_t streamPos;
if (i > oldCurrentStream ||
(i == oldCurrentStream && !oldStartedReadingCurrent)) {
streamPos = 0;
} else {
rv = TellMaybeSeek(stream, &streamPos);
if (NS_WARN_IF(NS_FAILED(rv))) {
return rv;
}
}
// See if we need to seek current stream forward or backward
if (remaining < streamPos) {
rv = stream->Seek(NS_SEEK_SET, remaining);
if (NS_WARN_IF(NS_FAILED(rv))) {
return 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 = AvailableMaybeSeek(mStreams[i], &avail);
if (NS_WARN_IF(NS_FAILED(rv))) {
return rv;
}
int64_t newPos = XPCOM_MIN(remaining, streamPos + (int64_t)avail);
rv = stream->Seek(NS_SEEK_SET, newPos);
if (NS_WARN_IF(NS_FAILED(rv))) {
return 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 = AvailableMaybeSeek(mStreams[i], &avail);
if (NS_WARN_IF(NS_FAILED(rv))) {
return rv;
}
int64_t seek = XPCOM_MIN((int64_t)avail, remaining);
rv = stream->Seek(NS_SEEK_CUR, seek);
if (NS_WARN_IF(NS_FAILED(rv))) {
return 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 = TellMaybeSeek(stream, &pos);
if (NS_WARN_IF(NS_FAILED(rv))) {
return rv;
}
int64_t seek = XPCOM_MIN(pos, remaining);
rv = stream->Seek(NS_SEEK_CUR, -seek);
if (NS_WARN_IF(NS_FAILED(rv))) {
return 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);
if (NS_WARN_IF(NS_FAILED(rv))) {
return rv;
}
} else {
break;
}
}
// Get position in current stream
int64_t streamPos;
if (i < oldCurrentStream) {
streamPos = 0;
} else {
uint64_t avail;
rv = AvailableMaybeSeek(mStreams[i], &avail);
if (NS_WARN_IF(NS_FAILED(rv))) {
return rv;
}
streamPos = avail;
}
// See if we have enough data in the current stream.
if (DeprecatedAbs(remaining) < streamPos) {
rv = stream->Seek(NS_SEEK_END, remaining);
if (NS_WARN_IF(NS_FAILED(rv))) {
return 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 = TellMaybeSeek(stream, &avail);
if (NS_WARN_IF(NS_FAILED(rv))) {
return rv;
}
int64_t newPos = streamPos + XPCOM_MIN(avail, DeprecatedAbs(remaining));
rv = stream->Seek(NS_SEEK_END, -newPos);
if (NS_WARN_IF(NS_FAILED(rv))) {
return 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* aResult)
{
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]);
if (NS_WARN_IF(!stream)) {
return NS_ERROR_NO_INTERFACE;
}
int64_t pos;
rv = TellMaybeSeek(stream, &pos);
if (NS_WARN_IF(NS_FAILED(rv))) {
return rv;
}
ret64 += pos;
}
*aResult = ret64;
return NS_OK;
}
/* void setEOF (); */
NS_IMETHODIMP
nsMultiplexInputStream::SetEOF()
{
return NS_ERROR_NOT_IMPLEMENTED;
}
nsresult
nsMultiplexInputStreamConstructor(nsISupports* aOuter,
REFNSIID aIID,
void** aResult)
{
*aResult = nullptr;
if (aOuter) {
return NS_ERROR_NO_AGGREGATION;
}
nsMultiplexInputStream* inst = new nsMultiplexInputStream();
if (!inst) {
return NS_ERROR_OUT_OF_MEMORY;
}
NS_ADDREF(inst);
nsresult rv = inst->QueryInterface(aIID, aResult);
NS_RELEASE(inst);
return rv;
}
void
nsMultiplexInputStream::Serialize(InputStreamParams& aParams,
FileDescriptorArray& aFileDescriptors)
{
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++) {
InputStreamParams childStreamParams;
SerializeInputStream(mStreams[index], childStreamParams,
aFileDescriptors);
streams.AppendElement(childStreamParams);
}
}
params.currentStream() = mCurrentStream;
params.status() = mStatus;
params.startedReadingCurrent() = mStartedReadingCurrent;
aParams = params;
}
bool
nsMultiplexInputStream::Deserialize(const InputStreamParams& aParams,
const FileDescriptorArray& aFileDescriptors)
{
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], aFileDescriptors);
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;
}