Quelle nsStreamUtils.cpp Sprache: 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/. */

#include "mozilla/Mutex.h"
#include "mozilla/Attributes.h"
#include "mozilla/InputStreamLengthWrapper.h"
#include "nsIInputStreamLength.h"
#include "nsStreamUtils.h"
#include "nsCOMPtr.h"
#include "nsICloneableInputStream.h"
#include "nsIEventTarget.h"
#include "nsICancelableRunnable.h"
#include "nsISafeOutputStream.h"
#include "nsString.h"
#include "nsIAsyncInputStream.h"
#include "nsIAsyncOutputStream.h"
#include "nsIBufferedStreams.h"
#include "nsIPipe.h"
#include "nsNetCID.h"
#include "nsServiceManagerUtils.h"
#include "nsThreadUtils.h"
#include "nsITransport.h"
#include "nsIStreamTransportService.h"
#include "NonBlockingAsyncInputStream.h"

using namespace mozilla;

static NS_DEFINE_CID(kStreamTransportServiceCID, NS_STREAMTRANSPORTSERVICE_CID);

//-----------------------------------------------------------------------------

// This is a nsICancelableRunnable because we can dispatch it to Workers and
// those can be shut down at any time, and in these cases, Cancel() is called
// instead of Run().
class nsInputStreamReadyEvent final : public CancelableRunnable,
                                      public nsIInputStreamCallback,
                                      public nsIRunnablePriority {
public:
  NS_DECL_ISUPPORTS_INHERITED

  nsInputStreamReadyEvent(const char* aName, nsIInputStreamCallback* aCallback,
                          nsIEventTarget* aTarget, uint32_t aPriority)
      : CancelableRunnable(aName),
        mCallback(aCallback),
        mTarget(aTarget),
        mPriority(aPriority) {}

private:
  ~nsInputStreamReadyEvent() {
    if (!mCallback) {
      return;
    }
    //
    // whoa!!  looks like we never posted this event.  take care to
    // release mCallback on the correct thread.  if mTarget lives on the
    // calling thread, then we are ok.  otherwise, we have to try to
    // proxy the Release over the right thread.  if that thread is dead,
    // then there's nothing we can do... better to leak than crash.
    //
    bool val;
    nsresult rv = mTarget->IsOnCurrentThread(&val);
    if (NS_FAILED(rv) || !val) {
      nsCOMPtr<nsIInputStreamCallback> event = NS_NewInputStreamReadyEvent(
          "~nsInputStreamReadyEvent", mCallback, mTarget, mPriority);
      mCallback = nullptr;
      if (event) {
        rv = event->OnInputStreamReady(nullptr);
        if (NS_FAILED(rv)) {
          MOZ_ASSERT_UNREACHABLE("leaking stream event");
          nsISupports* sup = event;
          NS_ADDREF(sup);
        }
      }
    }
  }

public:
  NS_IMETHOD OnInputStreamReady(nsIAsyncInputStream* aStream) override {
    mStream = aStream;

    nsresult rv = mTarget->Dispatch(this, NS_DISPATCH_NORMAL);
    if (NS_FAILED(rv)) {
      NS_WARNING("Dispatch failed");
      return NS_ERROR_FAILURE;
    }

    return NS_OK;
  }

  NS_IMETHOD Run() override {
    if (mCallback) {
      if (mStream) {
        mCallback->OnInputStreamReady(mStream);
      }
      mCallback = nullptr;
    }
    return NS_OK;
  }

  nsresult Cancel() override {
    mCallback = nullptr;
    return NS_OK;
  }

  NS_IMETHOD GetPriority(uint32_t* aPriority) override {
    *aPriority = mPriority;
    return NS_OK;
  }

private:
  nsCOMPtr<nsIAsyncInputStream> mStream;
  nsCOMPtr<nsIInputStreamCallback> mCallback;
  nsCOMPtr<nsIEventTarget> mTarget;
  uint32_t mPriority;
};

NS_IMPL_ISUPPORTS_INHERITED(nsInputStreamReadyEvent, CancelableRunnable,
                            nsIInputStreamCallback, nsIRunnablePriority)

//-----------------------------------------------------------------------------

// This is a nsICancelableRunnable because we can dispatch it to Workers and
// those can be shut down at any time, and in these cases, Cancel() is called
// instead of Run().
class nsOutputStreamReadyEvent final : public CancelableRunnable,
                                       public nsIOutputStreamCallback {
public:
  NS_DECL_ISUPPORTS_INHERITED

  nsOutputStreamReadyEvent(nsIOutputStreamCallback* aCallback,
                           nsIEventTarget* aTarget)
      : CancelableRunnable("nsOutputStreamReadyEvent"),
        mCallback(aCallback),
        mTarget(aTarget) {}

private:
  ~nsOutputStreamReadyEvent() {
    if (!mCallback) {
      return;
    }
    //
    // whoa!!  looks like we never posted this event.  take care to
    // release mCallback on the correct thread.  if mTarget lives on the
    // calling thread, then we are ok.  otherwise, we have to try to
    // proxy the Release over the right thread.  if that thread is dead,
    // then there's nothing we can do... better to leak than crash.
    //
    bool val;
    nsresult rv = mTarget->IsOnCurrentThread(&val);
    if (NS_FAILED(rv) || !val) {
      nsCOMPtr<nsIOutputStreamCallback> event =
          NS_NewOutputStreamReadyEvent(mCallback, mTarget);
      mCallback = nullptr;
      if (event) {
        rv = event->OnOutputStreamReady(nullptr);
        if (NS_FAILED(rv)) {
          MOZ_ASSERT_UNREACHABLE("leaking stream event");
          nsISupports* sup = event;
          NS_ADDREF(sup);
        }
      }
    }
  }

public:
  NS_IMETHOD OnOutputStreamReady(nsIAsyncOutputStream* aStream) override {
    mStream = aStream;

    nsresult rv = mTarget->Dispatch(this, NS_DISPATCH_NORMAL);
    if (NS_FAILED(rv)) {
      NS_WARNING("PostEvent failed");
      return NS_ERROR_FAILURE;
    }

    return NS_OK;
  }

  NS_IMETHOD Run() override {
    if (mCallback) {
      if (mStream) {
        mCallback->OnOutputStreamReady(mStream);
      }
      mCallback = nullptr;
    }
    return NS_OK;
  }

  nsresult Cancel() override {
    mCallback = nullptr;
    return NS_OK;
  }

private:
  nsCOMPtr<nsIAsyncOutputStream> mStream;
  nsCOMPtr<nsIOutputStreamCallback> mCallback;
  nsCOMPtr<nsIEventTarget> mTarget;
};

NS_IMPL_ISUPPORTS_INHERITED(nsOutputStreamReadyEvent, CancelableRunnable,
                            nsIOutputStreamCallback)

//-----------------------------------------------------------------------------

already_AddRefed<nsIInputStreamCallback> NS_NewInputStreamReadyEvent(
    const char* aName, nsIInputStreamCallback* aCallback,
    nsIEventTarget* aTarget, uint32_t aPriority) {
  NS_ASSERTION(aCallback, "null callback");
  NS_ASSERTION(aTarget, "null target");
  RefPtr<nsInputStreamReadyEvent> ev =
      new nsInputStreamReadyEvent(aName, aCallback, aTarget, aPriority);
  return ev.forget();
}

already_AddRefed<nsIOutputStreamCallback> NS_NewOutputStreamReadyEvent(
    nsIOutputStreamCallback* aCallback, nsIEventTarget* aTarget) {
  NS_ASSERTION(aCallback, "null callback");
  NS_ASSERTION(aTarget, "null target");
  RefPtr<nsOutputStreamReadyEvent> ev =
      new nsOutputStreamReadyEvent(aCallback, aTarget);
  return ev.forget();
}

//-----------------------------------------------------------------------------
// NS_AsyncCopy implementation

// abstract stream copier...
class nsAStreamCopier : public nsIInputStreamCallback,
                        public nsIOutputStreamCallback,
                        public CancelableRunnable {
public:
  NS_DECL_ISUPPORTS_INHERITED

  nsAStreamCopier()
      : CancelableRunnable("nsAStreamCopier"),
        mLock("nsAStreamCopier.mLock"),
        mCallback(nullptr),
        mProgressCallback(nullptr),
        mClosure(nullptr),
        mChunkSize(0),
        mEventInProcess(false),
        mEventIsPending(false),
        mCloseSource(true),
        mCloseSink(true),
        mCanceled(false),
        mCancelStatus(NS_OK) {}

  // kick off the async copy...
  nsresult Start(nsIInputStream* aSource, nsIOutputStream* aSink,
                 nsIEventTarget* aTarget, nsAsyncCopyCallbackFun aCallback,
                 void* aClosure, uint32_t aChunksize, bool aCloseSource,
                 bool aCloseSink, nsAsyncCopyProgressFun aProgressCallback) {
    mSource = aSource;
    mSink = aSink;
    mTarget = aTarget;
    mCallback = aCallback;
    mClosure = aClosure;
    mChunkSize = aChunksize;
    mCloseSource = aCloseSource;
    mCloseSink = aCloseSink;
    mProgressCallback = aProgressCallback;

    mAsyncSource = do_QueryInterface(mSource);
    mAsyncSink = do_QueryInterface(mSink);

    return PostContinuationEvent();
  }

  // implemented by subclasses, returns number of bytes copied and
  // sets source and sink condition before returning.
  virtual uint32_t DoCopy(nsresult* aSourceCondition,
                          nsresult* aSinkCondition) = 0;

  void Process() {
    if (!mSource || !mSink) {
      return;
    }

    nsresult cancelStatus;
    bool canceled;
    {
      MutexAutoLock lock(mLock);
      canceled = mCanceled;
      cancelStatus = mCancelStatus;
    }

    // If the copy was canceled before Process() was even called, then
    // sourceCondition and sinkCondition should be set to error results to
    // ensure we don't call Finish() on a canceled nsISafeOutputStream.
    MOZ_ASSERT(NS_FAILED(cancelStatus) == canceled, "cancel needs an error");
    nsresult sourceCondition = cancelStatus;
    nsresult sinkCondition = cancelStatus;

    // Copy data from the source to the sink until we hit failure or have
    // copied all the data.
    for (;;) {
      // Note: copyFailed will be true if the source or the sink have
      //       reported an error, or if we failed to write any bytes
      //       because we have consumed all of our data.
      bool copyFailed = false;
      if (!canceled) {
        uint32_t n = DoCopy(&sourceCondition, &sinkCondition);
        if (n > 0 && mProgressCallback) {
          mProgressCallback(mClosure, n);
        }
        copyFailed =
            NS_FAILED(sourceCondition) || NS_FAILED(sinkCondition) || n == 0;

        MutexAutoLock lock(mLock);
        canceled = mCanceled;
        cancelStatus = mCancelStatus;
      }
      if (copyFailed && !canceled) {
        if (sourceCondition == NS_BASE_STREAM_WOULD_BLOCK && mAsyncSource) {
          // need to wait for more data from source.  while waiting for
          // more source data, be sure to observe failures on output end.
          mAsyncSource->AsyncWait(this, 0, 0, nullptr);

          if (mAsyncSink) {
            mAsyncSink->AsyncWait(this, nsIAsyncOutputStream::WAIT_CLOSURE_ONLY,
                                  0, nullptr);
          }
          break;
        }
        if (sinkCondition == NS_BASE_STREAM_WOULD_BLOCK && mAsyncSink) {
          // need to wait for more room in the sink.  while waiting for
          // more room in the sink, be sure to observer failures on the
          // input end.
          mAsyncSink->AsyncWait(this, 0, 0, nullptr);

          if (mAsyncSource) {
            mAsyncSource->AsyncWait(
                this, nsIAsyncInputStream::WAIT_CLOSURE_ONLY, 0, nullptr);
          }
          break;
        }
      }
      if (copyFailed || canceled) {
        if (mAsyncSource) {
          // cancel any previously-registered AsyncWait callbacks to avoid leaks
          mAsyncSource->AsyncWait(nullptr, 0, 0, nullptr);
        }
        if (mCloseSource) {
          // close source
          if (mAsyncSource) {
            mAsyncSource->CloseWithStatus(canceled ? cancelStatus
                                                   : sinkCondition);
          } else {
            mSource->Close();
          }
        }
        mAsyncSource = nullptr;
        mSource = nullptr;

        if (mAsyncSink) {
          // cancel any previously-registered AsyncWait callbacks to avoid leaks
          mAsyncSink->AsyncWait(nullptr, 0, 0, nullptr);
        }
        if (mCloseSink) {
          // close sink
          if (mAsyncSink) {
            mAsyncSink->CloseWithStatus(canceled ? cancelStatus
                                                 : sourceCondition);
          } else {
            // If we have an nsISafeOutputStream, and our
            // sourceCondition and sinkCondition are not set to a
            // failure state, finish writing.
            nsCOMPtr<nsISafeOutputStream> sostream = do_QueryInterface(mSink);
            if (sostream && NS_SUCCEEDED(sourceCondition) &&
                NS_SUCCEEDED(sinkCondition)) {
              sostream->Finish();
            } else {
              mSink->Close();
            }
          }
        }
        mAsyncSink = nullptr;
        mSink = nullptr;

        // notify state complete...
        if (mCallback) {
          nsresult status;
          if (!canceled) {
            status = sourceCondition;
            if (NS_SUCCEEDED(status)) {
              status = sinkCondition;
            }
            if (status == NS_BASE_STREAM_CLOSED) {
              status = NS_OK;
            }
          } else {
            status = cancelStatus;
          }
          mCallback(mClosure, status);
        }
        break;
      }
    }
  }

  nsresult Cancel(nsresult aReason) {
    MutexAutoLock lock(mLock);
    if (mCanceled) {
      return NS_ERROR_FAILURE;
    }

    if (NS_SUCCEEDED(aReason)) {
      NS_WARNING("cancel with non-failure status code");
      aReason = NS_BASE_STREAM_CLOSED;
    }

    mCanceled = true;
    mCancelStatus = aReason;
    return NS_OK;
  }

  NS_IMETHOD OnInputStreamReady(nsIAsyncInputStream* aSource) override {
    PostContinuationEvent();
    return NS_OK;
  }

  NS_IMETHOD OnOutputStreamReady(nsIAsyncOutputStream* aSink) override {
    PostContinuationEvent();
    return NS_OK;
  }

  // continuation event handler
  NS_IMETHOD Run() override {
    Process();

    // clear "in process" flag and post any pending continuation event
    MutexAutoLock lock(mLock);
    mEventInProcess = false;
    if (mEventIsPending) {
      mEventIsPending = false;
      PostContinuationEvent_Locked();
    }

    return NS_OK;
  }

  nsresult Cancel() MOZ_MUST_OVERRIDE override = 0;

  nsresult PostContinuationEvent() {
    // we cannot post a continuation event if there is currently
    // an event in process.  doing so could result in Process being
    // run simultaneously on multiple threads, so we mark the event
    // as pending, and if an event is already in process then we
    // just let that existing event take care of posting the real
    // continuation event.

    MutexAutoLock lock(mLock);
    return PostContinuationEvent_Locked();
  }

  nsresult PostContinuationEvent_Locked() MOZ_REQUIRES(mLock) {
    nsresult rv = NS_OK;
    if (mEventInProcess) {
      mEventIsPending = true;
    } else {
      rv = mTarget->Dispatch(this, NS_DISPATCH_NORMAL);
      if (NS_SUCCEEDED(rv)) {
        mEventInProcess = true;
      } else {
        NS_WARNING("unable to post continuation event");
      }
    }
    return rv;
  }

protected:
  nsCOMPtr<nsIInputStream> mSource;
  nsCOMPtr<nsIOutputStream> mSink;
  nsCOMPtr<nsIAsyncInputStream> mAsyncSource;
  nsCOMPtr<nsIAsyncOutputStream> mAsyncSink;
  nsCOMPtr<nsIEventTarget> mTarget;
  Mutex mLock;
  nsAsyncCopyCallbackFun mCallback;
  nsAsyncCopyProgressFun mProgressCallback;
  void* mClosure;
  uint32_t mChunkSize;
  bool mEventInProcess MOZ_GUARDED_BY(mLock);
  bool mEventIsPending MOZ_GUARDED_BY(mLock);
  bool mCloseSource;
  bool mCloseSink;
  bool mCanceled MOZ_GUARDED_BY(mLock);
  nsresult mCancelStatus MOZ_GUARDED_BY(mLock);

  // virtual since subclasses call superclass Release()
  virtual ~nsAStreamCopier() = default;
};

NS_IMPL_ISUPPORTS_INHERITED(nsAStreamCopier, CancelableRunnable,
                            nsIInputStreamCallback, nsIOutputStreamCallback)

class nsStreamCopierIB final : public nsAStreamCopier {
public:
  nsStreamCopierIB() = default;
  virtual ~nsStreamCopierIB() = default;

  struct MOZ_STACK_CLASS ReadSegmentsState {
    // the nsIOutputStream will outlive the ReadSegmentsState on the stack
    nsIOutputStream* MOZ_NON_OWNING_REF mSink;
    nsresult mSinkCondition;
  };

  static nsresult ConsumeInputBuffer(nsIInputStream* aInStr, void* aClosure,
                                     const char* aBuffer, uint32_t aOffset,
                                     uint32_t aCount, uint32_t* aCountWritten) {
    ReadSegmentsState* state = (ReadSegmentsState*)aClosure;

    nsresult rv = state->mSink->Write(aBuffer, aCount, aCountWritten);
    if (NS_FAILED(rv)) {
      state->mSinkCondition = rv;
    } else if (*aCountWritten == 0) {
      state->mSinkCondition = NS_BASE_STREAM_CLOSED;
    }

    return state->mSinkCondition;
  }

  uint32_t DoCopy(nsresult* aSourceCondition,
                  nsresult* aSinkCondition) override {
    ReadSegmentsState state;
    state.mSink = mSink;
    state.mSinkCondition = NS_OK;

    uint32_t n;
    *aSourceCondition =
        mSource->ReadSegments(ConsumeInputBuffer, &state, mChunkSize, &n);
    *aSinkCondition = NS_SUCCEEDED(state.mSinkCondition) && n == 0
                          ? mSink->StreamStatus()
                          : state.mSinkCondition;
    return n;
  }

  nsresult Cancel() override { return NS_OK; }
};

class nsStreamCopierOB final : public nsAStreamCopier {
public:
  nsStreamCopierOB() = default;
  virtual ~nsStreamCopierOB() = default;

  struct MOZ_STACK_CLASS WriteSegmentsState {
    // the nsIInputStream will outlive the WriteSegmentsState on the stack
    nsIInputStream* MOZ_NON_OWNING_REF mSource;
    nsresult mSourceCondition;
  };

  static nsresult FillOutputBuffer(nsIOutputStream* aOutStr, void* aClosure,
                                   char* aBuffer, uint32_t aOffset,
                                   uint32_t aCount, uint32_t* aCountRead) {
    WriteSegmentsState* state = (WriteSegmentsState*)aClosure;

    nsresult rv = state->mSource->Read(aBuffer, aCount, aCountRead);
    if (NS_FAILED(rv)) {
      state->mSourceCondition = rv;
    } else if (*aCountRead == 0) {
      state->mSourceCondition = NS_BASE_STREAM_CLOSED;
    }

    return state->mSourceCondition;
  }

  uint32_t DoCopy(nsresult* aSourceCondition,
                  nsresult* aSinkCondition) override {
    WriteSegmentsState state;
    state.mSource = mSource;
    state.mSourceCondition = NS_OK;

    uint32_t n;
    *aSinkCondition =
        mSink->WriteSegments(FillOutputBuffer, &state, mChunkSize, &n);
    *aSourceCondition = NS_SUCCEEDED(state.mSourceCondition) && n == 0
                            ? mSource->StreamStatus()
                            : state.mSourceCondition;
    return n;
  }

  nsresult Cancel() override { return NS_OK; }
};

//-----------------------------------------------------------------------------

nsresult NS_AsyncCopy(nsIInputStream* aSource, nsIOutputStream* aSink,
                      nsIEventTarget* aTarget, nsAsyncCopyMode aMode,
                      uint32_t aChunkSize, nsAsyncCopyCallbackFun aCallback,
                      void* aClosure, bool aCloseSource, bool aCloseSink,
                      nsISupports** aCopierCtx,
                      nsAsyncCopyProgressFun aProgressCallback) {
  NS_ASSERTION(aTarget, "non-null target required");

  nsresult rv;
  nsAStreamCopier* copier;

  if (aMode == NS_ASYNCCOPY_VIA_READSEGMENTS) {
    copier = new nsStreamCopierIB();
  } else {
    copier = new nsStreamCopierOB();
  }

  // Start() takes an owning ref to the copier...
  NS_ADDREF(copier);
  rv = copier->Start(aSource, aSink, aTarget, aCallback, aClosure, aChunkSize,
                     aCloseSource, aCloseSink, aProgressCallback);

  if (aCopierCtx) {
    *aCopierCtx = static_cast<nsISupports*>(static_cast<nsIRunnable*>(copier));
    NS_ADDREF(*aCopierCtx);
  }
  NS_RELEASE(copier);

  return rv;
}

//-----------------------------------------------------------------------------

nsresult NS_CancelAsyncCopy(nsISupports* aCopierCtx, nsresult aReason) {
  nsAStreamCopier* copier =
      static_cast<nsAStreamCopier*>(static_cast<nsIRunnable*>(aCopierCtx));
  return copier->Cancel(aReason);
}

//-----------------------------------------------------------------------------

namespace {
template <typename T>
struct ResultTraits {};

template <>
struct ResultTraits<nsACString> {
  static void Clear(nsACString& aString) { aString.Truncate(); }

  static char* GetStorage(nsACString& aString) {
    return aString.BeginWriting();
  }
};

template <>
struct ResultTraits<nsTArray<uint8_t>> {
  static void Clear(nsTArray<uint8_t>& aArray) { aArray.Clear(); }

  static char* GetStorage(nsTArray<uint8_t>& aArray) {
    return reinterpret_cast<char*>(aArray.Elements());
  }
};
}  // namespace

template <typename T>
nsresult DoConsumeStream(nsIInputStream* aStream, uint32_t aMaxCount,
                         T& aResult) {
  nsresult rv = NS_OK;
  ResultTraits<T>::Clear(aResult);

  while (aMaxCount) {
    uint64_t avail64;
    rv = aStream->Available(&avail64);
    if (NS_FAILED(rv)) {
      if (rv == NS_BASE_STREAM_CLOSED) {
        rv = NS_OK;
      }
      break;
    }
    if (avail64 == 0) {
      break;
    }

    uint32_t avail = (uint32_t)XPCOM_MIN<uint64_t>(avail64, aMaxCount);

    // resize aResult buffer
    uint32_t length = aResult.Length();
    CheckedInt<uint32_t> newLength = CheckedInt<uint32_t>(length) + avail;
    if (!newLength.isValid()) {
      return NS_ERROR_FILE_TOO_BIG;
    }

    if (!aResult.SetLength(newLength.value(), fallible)) {
      return NS_ERROR_OUT_OF_MEMORY;
    }
    char* buf = ResultTraits<T>::GetStorage(aResult) + length;

    uint32_t n;
    rv = aStream->Read(buf, avail, &n);
    if (NS_FAILED(rv)) {
      break;
    }
    if (n != avail) {
      MOZ_ASSERT(n < avail, "What happened there???");
      aResult.SetLength(length + n);
    }
    if (n == 0) {
      break;
    }
    aMaxCount -= n;
  }

  return rv;
}

nsresult NS_ConsumeStream(nsIInputStream* aStream, uint32_t aMaxCount,
                          nsACString& aResult) {
  return DoConsumeStream(aStream, aMaxCount, aResult);
}

nsresult NS_ConsumeStream(nsIInputStream* aStream, uint32_t aMaxCount,
                          nsTArray<uint8_t>& aResult) {
  return DoConsumeStream(aStream, aMaxCount, aResult);
}

//-----------------------------------------------------------------------------

static nsresult TestInputStream(nsIInputStream* aInStr, void* aClosure,
                                const char* aBuffer, uint32_t aOffset,
                                uint32_t aCount, uint32_t* aCountWritten) {
  bool* result = static_cast<bool*>(aClosure);
  *result = true;
  *aCountWritten = 0;
  return NS_ERROR_ABORT;  // don't call me anymore
}

bool NS_InputStreamIsBuffered(nsIInputStream* aStream) {
  nsCOMPtr<nsIBufferedInputStream> bufferedIn = do_QueryInterface(aStream);
  if (bufferedIn) {
    return true;
  }

  bool result = false;
  uint32_t n;
  nsresult rv = aStream->ReadSegments(TestInputStream, &result, 1, &n);
  return result || rv != NS_ERROR_NOT_IMPLEMENTED;
}

static nsresult TestOutputStream(nsIOutputStream* aOutStr, void* aClosure,
                                 char* aBuffer, uint32_t aOffset,
                                 uint32_t aCount, uint32_t* aCountRead) {
  bool* result = static_cast<bool*>(aClosure);
  *result = true;
  *aCountRead = 0;
  return NS_ERROR_ABORT;  // don't call me anymore
}

bool NS_OutputStreamIsBuffered(nsIOutputStream* aStream) {
  nsCOMPtr<nsIBufferedOutputStream> bufferedOut = do_QueryInterface(aStream);
  if (bufferedOut) {
    return true;
  }

  bool result = false;
  uint32_t n;
  aStream->WriteSegments(TestOutputStream, &result, 1, &n);
  return result;
}

//-----------------------------------------------------------------------------

nsresult NS_CopySegmentToStream(nsIInputStream* aInStr, void* aClosure,
                                const char* aBuffer, uint32_t aOffset,
                                uint32_t aCount, uint32_t* aCountWritten) {
  nsIOutputStream* outStr = static_cast<nsIOutputStream*>(aClosure);
  *aCountWritten = 0;
  while (aCount) {
    uint32_t n;
    nsresult rv = outStr->Write(aBuffer, aCount, &n);
    if (NS_FAILED(rv)) {
      return rv;
    }
    aBuffer += n;
    aCount -= n;
    *aCountWritten += n;
  }
  return NS_OK;
}

nsresult NS_CopySegmentToBuffer(nsIInputStream* aInStr, void* aClosure,
                                const char* aBuffer, uint32_t aOffset,
                                uint32_t aCount, uint32_t* aCountWritten) {
  char* toBuf = static_cast<char*>(aClosure);
  memcpy(&toBuf[aOffset], aBuffer, aCount);
  *aCountWritten = aCount;
  return NS_OK;
}

nsresult NS_CopyBufferToSegment(nsIOutputStream* aOutStr, void* aClosure,
                                char* aBuffer, uint32_t aOffset,
                                uint32_t aCount, uint32_t* aCountRead) {
  const char* fromBuf = static_cast<const char*>(aClosure);
  memcpy(aBuffer, &fromBuf[aOffset], aCount);
  *aCountRead = aCount;
  return NS_OK;
}

nsresult NS_CopyStreamToSegment(nsIOutputStream* aOutputStream, void* aClosure,
                                char* aToSegment, uint32_t aFromOffset,
                                uint32_t aCount, uint32_t* aReadCount) {
  nsIInputStream* fromStream = static_cast<nsIInputStream*>(aClosure);
  return fromStream->Read(aToSegment, aCount, aReadCount);
}

nsresult NS_DiscardSegment(nsIInputStream* aInStr, void* aClosure,
                           const char* aBuffer, uint32_t aOffset,
                           uint32_t aCount, uint32_t* aCountWritten) {
  *aCountWritten = aCount;
  return NS_OK;
}

//-----------------------------------------------------------------------------

nsresult NS_WriteSegmentThunk(nsIInputStream* aInStr, void* aClosure,
                              const char* aBuffer, uint32_t aOffset,
                              uint32_t aCount, uint32_t* aCountWritten) {
  nsWriteSegmentThunk* thunk = static_cast<nsWriteSegmentThunk*>(aClosure);
  return thunk->mFun(thunk->mStream, thunk->mClosure, aBuffer, aOffset, aCount,
                     aCountWritten);
}

nsresult NS_FillArray(FallibleTArray<char>& aDest, nsIInputStream* aInput,
                      uint32_t aKeep, uint32_t* aNewBytes) {
  MOZ_ASSERT(aInput, "null stream");
  MOZ_ASSERT(aKeep <= aDest.Length(), "illegal keep count");

  char* aBuffer = aDest.Elements();
  int64_t keepOffset = int64_t(aDest.Length()) - aKeep;
  if (aKeep != 0 && keepOffset > 0) {
    memmove(aBuffer, aBuffer + keepOffset, aKeep);
  }

  nsresult rv =
      aInput->Read(aBuffer + aKeep, aDest.Capacity() - aKeep, aNewBytes);
  if (NS_FAILED(rv)) {
    *aNewBytes = 0;
  }
  // NOTE: we rely on the fact that the new slots are NOT initialized by
  // SetLengthAndRetainStorage here, see nsTArrayElementTraits::Construct()
  // in nsTArray.h:
  aDest.SetLengthAndRetainStorage(aKeep + *aNewBytes);

  MOZ_ASSERT(aDest.Length() <= aDest.Capacity(), "buffer overflow");
  return rv;
}

bool NS_InputStreamIsCloneable(nsIInputStream* aSource) {
  if (!aSource) {
    return false;
  }

  nsCOMPtr<nsICloneableInputStream> cloneable = do_QueryInterface(aSource);
  return cloneable && cloneable->GetCloneable();
}

nsresult NS_CloneInputStream(nsIInputStream* aSource,
                             nsIInputStream** aCloneOut,
                             nsIInputStream** aReplacementOut) {
  if (NS_WARN_IF(!aSource)) {
    return NS_ERROR_FAILURE;
  }

  // Attempt to perform the clone directly on the source stream
  nsCOMPtr<nsICloneableInputStream> cloneable = do_QueryInterface(aSource);
  if (cloneable && cloneable->GetCloneable()) {
    if (aReplacementOut) {
      *aReplacementOut = nullptr;
    }
    return cloneable->Clone(aCloneOut);
  }

  // If we failed the clone and the caller does not want to replace their
  // original stream, then we are done.  Return error.
  if (!aReplacementOut) {
    return NS_ERROR_FAILURE;
  }

  // The caller has opted-in to the fallback clone support that replaces
  // the original stream.  Copy the data to a pipe and return two cloned
  // input streams.

  nsCOMPtr<nsIInputStream> reader;
  nsCOMPtr<nsIInputStream> readerClone;
  nsCOMPtr<nsIOutputStream> writer;

  NS_NewPipe(getter_AddRefs(reader), getter_AddRefs(writer), 0,
             0,            // default segment size and max size
             true, true);  // non-blocking

  // Propagate length information provided by nsIInputStreamLength. We don't use
  // InputStreamLengthHelper::GetSyncLength to avoid the risk of blocking when
  // called off-main-thread.
  int64_t length = -1;
  if (nsCOMPtr<nsIInputStreamLength> streamLength = do_QueryInterface(aSource);
      streamLength && NS_SUCCEEDED(streamLength->Length(&length)) &&
      length != -1) {
    reader = new mozilla::InputStreamLengthWrapper(reader.forget(), length);
  }

  cloneable = do_QueryInterface(reader);
  MOZ_ASSERT(cloneable && cloneable->GetCloneable());

  nsresult rv = cloneable->Clone(getter_AddRefs(readerClone));
  if (NS_WARN_IF(NS_FAILED(rv))) {
    return rv;
  }

  nsCOMPtr<nsIEventTarget> target =
      do_GetService(NS_STREAMTRANSPORTSERVICE_CONTRACTID, &rv);
  if (NS_WARN_IF(NS_FAILED(rv))) {
    return rv;
  }

  rv = NS_AsyncCopy(aSource, writer, target, NS_ASYNCCOPY_VIA_WRITESEGMENTS);
  if (NS_WARN_IF(NS_FAILED(rv))) {
    return rv;
  }

  readerClone.forget(aCloneOut);
  reader.forget(aReplacementOut);

  return NS_OK;
}

nsresult NS_MakeAsyncNonBlockingInputStream(
    already_AddRefed<nsIInputStream> aSource,
    nsIAsyncInputStream** aAsyncInputStream, bool aCloseWhenDone,
    uint32_t aFlags, uint32_t aSegmentSize, uint32_t aSegmentCount) {
  nsCOMPtr<nsIInputStream> source = std::move(aSource);
  if (NS_WARN_IF(!aAsyncInputStream)) {
    return NS_ERROR_FAILURE;
  }

  bool nonBlocking = false;
  nsresult rv = source->IsNonBlocking(&nonBlocking);
  if (NS_WARN_IF(NS_FAILED(rv))) {
    return rv;
  }

  nsCOMPtr<nsIAsyncInputStream> asyncStream = do_QueryInterface(source);

  if (nonBlocking && asyncStream) {
    // This stream is perfect!
    asyncStream.forget(aAsyncInputStream);
    return NS_OK;
  }

  if (nonBlocking) {
    // If the stream is non-blocking but not async, we wrap it.
    return NonBlockingAsyncInputStream::Create(source.forget(),
                                               aAsyncInputStream);
  }

  nsCOMPtr<nsIStreamTransportService> sts =
      do_GetService(kStreamTransportServiceCID, &rv);
  if (NS_WARN_IF(NS_FAILED(rv))) {
    return rv;
  }

  nsCOMPtr<nsITransport> transport;
  rv = sts->CreateInputTransport(source, aCloseWhenDone,
                                 getter_AddRefs(transport));
  if (NS_WARN_IF(NS_FAILED(rv))) {
    return rv;
  }

  nsCOMPtr<nsIInputStream> wrapper;
  rv = transport->OpenInputStream(aFlags, aSegmentSize, aSegmentCount,
                                  getter_AddRefs(wrapper));
  if (NS_WARN_IF(NS_FAILED(rv))) {
    return rv;
  }

  asyncStream = do_QueryInterface(wrapper);
  MOZ_ASSERT(asyncStream);

  asyncStream.forget(aAsyncInputStream);
  return NS_OK;
}

quality99%

¤ Dauer der Verarbeitung: 0.22 Sekunden (vorverarbeitet) ¤

Wurzel

Suchen

Beweissystem der NASA

Beweissystem Isabelle

NIST Cobol Testsuite

Cephes Mathematical Library

Wiener Entwicklungsmethode

Haftungshinweis

Die Informationen auf dieser Webseite wurden nach bestem Wissen sorgfältig zusammengestellt. Es wird jedoch weder Vollständigkeit, noch Richtigkeit, noch Qualität der bereit gestellten Informationen zugesichert.

Bemerkung:

Die farbliche Syntaxdarstellung ist noch experimentell.