gecko-dev/ipc/glue/IPCStreamDestination.cpp

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/* -*- 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/. */
#include "IPCStreamDestination.h"
#include "mozilla/Mutex.h"
#include "nsIAsyncInputStream.h"
#include "nsIAsyncOutputStream.h"
#include "nsIBufferedStreams.h"
#include "nsICloneableInputStream.h"
#include "nsIPipe.h"
namespace mozilla {
namespace ipc {
// ----------------------------------------------------------------------------
// IPCStreamDestination::DelayedStartInputStream
//
// When AutoIPCStream is used with delayedStart, we need to ask for data at the
// first real use of the nsIInputStream. In order to do so, we wrap the
// nsIInputStream, created by the nsIPipe, with this wrapper.
class IPCStreamDestination::DelayedStartInputStream final
: public nsIAsyncInputStream
, public nsISearchableInputStream
, public nsICloneableInputStream
, public nsIBufferedInputStream
{
public:
NS_DECL_THREADSAFE_ISUPPORTS
DelayedStartInputStream(IPCStreamDestination* aDestination,
already_AddRefed<nsIAsyncInputStream>&& aStream)
: mDestination(aDestination)
, mStream(aStream)
, mMutex("IPCStreamDestination::DelayedStartInputStream::mMutex")
{
MOZ_ASSERT(mDestination);
MOZ_ASSERT(mStream);
}
void
DestinationShutdown()
{
MutexAutoLock lock(mMutex);
mDestination = nullptr;
}
// nsIInputStream interface
NS_IMETHOD
Close() override
{
MaybeCloseDestination();
return mStream->Close();
}
NS_IMETHOD
Available(uint64_t* aLength) override
{
MaybeStartReading();
return mStream->Available(aLength);
}
NS_IMETHOD
Read(char* aBuffer, uint32_t aCount, uint32_t* aReadCount) override
{
MaybeStartReading();
return mStream->Read(aBuffer, aCount, aReadCount);
}
NS_IMETHOD
ReadSegments(nsWriteSegmentFun aWriter, void* aClosure, uint32_t aCount,
uint32_t *aResult) override
{
MaybeStartReading();
return mStream->ReadSegments(aWriter, aClosure, aCount, aResult);
}
NS_IMETHOD
IsNonBlocking(bool* aNonBlocking) override
{
MaybeStartReading();
return mStream->IsNonBlocking(aNonBlocking);
}
// nsIAsyncInputStream interface
NS_IMETHOD
CloseWithStatus(nsresult aReason) override
{
MaybeCloseDestination();
return mStream->CloseWithStatus(aReason);
}
NS_IMETHOD
AsyncWait(nsIInputStreamCallback* aCallback, uint32_t aFlags,
uint32_t aRequestedCount, nsIEventTarget* aTarget) override
{
MaybeStartReading();
return mStream->AsyncWait(aCallback, aFlags, aRequestedCount, aTarget);
}
NS_IMETHOD
Search(const char* aForString, bool aIgnoreCase, bool* aFound,
uint32_t* aOffsetSearchedTo) override
{
MaybeStartReading();
nsCOMPtr<nsISearchableInputStream> searchable = do_QueryInterface(mStream);
MOZ_ASSERT(searchable);
return searchable->Search(aForString, aIgnoreCase, aFound, aOffsetSearchedTo);
}
// nsICloneableInputStream interface
NS_IMETHOD
GetCloneable(bool* aCloneable) override
{
MaybeStartReading();
nsCOMPtr<nsICloneableInputStream> cloneable = do_QueryInterface(mStream);
MOZ_ASSERT(cloneable);
return cloneable->GetCloneable(aCloneable);
}
NS_IMETHOD
Clone(nsIInputStream** aResult) override
{
MaybeStartReading();
nsCOMPtr<nsICloneableInputStream> cloneable = do_QueryInterface(mStream);
MOZ_ASSERT(cloneable);
return cloneable->Clone(aResult);
}
// nsIBufferedInputStream
NS_IMETHOD
Init(nsIInputStream* aStream, uint32_t aBufferSize) override
{
MaybeStartReading();
nsCOMPtr<nsIBufferedInputStream> stream = do_QueryInterface(mStream);
MOZ_ASSERT(stream);
return stream->Init(aStream, aBufferSize);
}
NS_IMETHODIMP
GetData(nsIInputStream **aResult) override
{
return NS_ERROR_NOT_IMPLEMENTED;
}
void
MaybeStartReading();
void
MaybeCloseDestination();
private:
~DelayedStartInputStream() = default;
IPCStreamDestination* mDestination;
nsCOMPtr<nsIAsyncInputStream> mStream;
// This protects mDestination: any method can be called by any thread.
Mutex mMutex;
class HelperRunnable;
};
class IPCStreamDestination::DelayedStartInputStream::HelperRunnable final
: public Runnable
{
public:
enum Op {
eStartReading,
eCloseDestination,
};
HelperRunnable(
IPCStreamDestination::DelayedStartInputStream* aDelayedStartInputStream,
Op aOp)
: Runnable(
"ipc::IPCStreamDestination::DelayedStartInputStream::HelperRunnable")
, mDelayedStartInputStream(aDelayedStartInputStream)
, mOp(aOp)
{
MOZ_ASSERT(aDelayedStartInputStream);
}
NS_IMETHOD
Run() override
{
switch (mOp) {
case eStartReading:
mDelayedStartInputStream->MaybeStartReading();
break;
case eCloseDestination:
mDelayedStartInputStream->MaybeCloseDestination();
break;
}
return NS_OK;
}
private:
RefPtr<IPCStreamDestination::DelayedStartInputStream> mDelayedStartInputStream;
Op mOp;
};
void
IPCStreamDestination::DelayedStartInputStream::MaybeStartReading()
{
MutexAutoLock lock(mMutex);
if (!mDestination) {
return;
}
if (mDestination->IsOnOwningThread()) {
mDestination->StartReading();
mDestination = nullptr;
return;
}
RefPtr<Runnable> runnable =
new HelperRunnable(this, HelperRunnable::eStartReading);
mDestination->DispatchRunnable(runnable.forget());
}
void
IPCStreamDestination::DelayedStartInputStream::MaybeCloseDestination()
{
MutexAutoLock lock(mMutex);
if (!mDestination) {
return;
}
if (mDestination->IsOnOwningThread()) {
mDestination->RequestClose(NS_ERROR_ABORT);
mDestination = nullptr;
return;
}
RefPtr<Runnable> runnable =
new HelperRunnable(this, HelperRunnable::eCloseDestination);
mDestination->DispatchRunnable(runnable.forget());
}
NS_IMPL_ADDREF(IPCStreamDestination::DelayedStartInputStream);
NS_IMPL_RELEASE(IPCStreamDestination::DelayedStartInputStream);
NS_INTERFACE_MAP_BEGIN(IPCStreamDestination::DelayedStartInputStream)
NS_INTERFACE_MAP_ENTRY(nsIAsyncInputStream)
NS_INTERFACE_MAP_ENTRY(nsISearchableInputStream)
NS_INTERFACE_MAP_ENTRY(nsICloneableInputStream)
NS_INTERFACE_MAP_ENTRY(nsIBufferedInputStream)
NS_INTERFACE_MAP_ENTRY_AMBIGUOUS(nsIInputStream, nsIAsyncInputStream)
NS_INTERFACE_MAP_ENTRY_AMBIGUOUS(nsISupports, nsIAsyncInputStream)
NS_INTERFACE_MAP_END
// ----------------------------------------------------------------------------
// IPCStreamDestination
IPCStreamDestination::IPCStreamDestination()
: mOwningThread(NS_GetCurrentThread())
, mDelayedStart(false)
{
}
IPCStreamDestination::~IPCStreamDestination()
{
}
nsresult
IPCStreamDestination::Initialize()
{
MOZ_ASSERT(!mReader);
MOZ_ASSERT(!mWriter);
// use async versions for both reader and writer even though we are
// opening the writer as an infinite stream. We want to be able to
// use CloseWithStatus() to communicate errors through the pipe.
// Use an "infinite" pipe because we cannot apply back-pressure through
// the async IPC layer at the moment. Blocking the IPC worker thread
// is not desirable, either.
nsresult rv = NS_NewPipe2(getter_AddRefs(mReader),
getter_AddRefs(mWriter),
true, true, // non-blocking
0, // segment size
UINT32_MAX); // "infinite" pipe
if (NS_WARN_IF(NS_FAILED(rv))) {
return rv;
}
return NS_OK;
}
void
IPCStreamDestination::SetDelayedStart(bool aDelayedStart)
{
mDelayedStart = aDelayedStart;
}
already_AddRefed<nsIInputStream>
IPCStreamDestination::TakeReader()
{
MOZ_ASSERT(mReader);
MOZ_ASSERT(!mDelayedStartInputStream);
if (mDelayedStart) {
mDelayedStartInputStream =
new DelayedStartInputStream(this, mReader.forget());
RefPtr<nsIAsyncInputStream> inputStream = mDelayedStartInputStream;
return inputStream.forget();
}
return mReader.forget();
}
bool
IPCStreamDestination::IsOnOwningThread() const
{
return mOwningThread == NS_GetCurrentThread();
}
void
IPCStreamDestination::DispatchRunnable(already_AddRefed<nsIRunnable>&& aRunnable)
{
nsCOMPtr<nsIRunnable> runnable = aRunnable;
mOwningThread->Dispatch(runnable.forget(), NS_DISPATCH_NORMAL);
}
void
IPCStreamDestination::ActorDestroyed()
{
MOZ_ASSERT(mWriter);
// If we were gracefully closed we should have gotten RecvClose(). In
// that case, the writer will already be closed and this will have no
// effect. This just aborts the writer in the case where the child process
// crashes.
mWriter->CloseWithStatus(NS_ERROR_ABORT);
if (mDelayedStartInputStream) {
mDelayedStartInputStream->DestinationShutdown();
mDelayedStartInputStream = nullptr;
}
}
void
IPCStreamDestination::BufferReceived(const nsCString& aBuffer)
{
MOZ_ASSERT(mWriter);
uint32_t numWritten = 0;
// This should only fail if we hit an OOM condition.
nsresult rv = mWriter->Write(aBuffer.get(), aBuffer.Length(), &numWritten);
if (NS_WARN_IF(NS_FAILED(rv))) {
RequestClose(rv);
}
}
void
IPCStreamDestination::CloseReceived(nsresult aRv)
{
MOZ_ASSERT(mWriter);
mWriter->CloseWithStatus(aRv);
TerminateDestination();
}
} // namespace ipc
} // namespace mozilla