The Tor Browser: netwerk/base/src/nsBufferedStreams.cpp@6474c204b198 (annotated)

netwerk/base/src/nsBufferedStreams.cpp@6474c204b198 (annotated)

netwerk/base/src/nsBufferedStreams.cpp

Wed, 31 Dec 2014 06:09:35 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Wed, 31 Dec 2014 06:09:35 +0100
changeset 0: 6474c204b198
permissions: -rw-r--r--

Cloned upstream origin tor-browser at tor-browser-31.3.0esr-4.5-1-build1
revision ID fc1c9ff7c1b2defdbc039f12214767608f46423f for hacking purpose.

 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
 /* 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 "ipc/IPCMessageUtils.h"
 #include "nsBufferedStreams.h"
 #include "nsStreamUtils.h"
 #include "nsNetCID.h"
 #include "nsIClassInfoImpl.h"
 #include "mozilla/ipc/InputStreamUtils.h"
 #include <algorithm>
 #ifdef DEBUG_brendan
 # define METERING
 #endif
 #ifdef METERING
 # include <stdio.h>
 # define METER(x)       x
 # define MAX_BIG_SEEKS  20
 static struct {
     uint32_t            mSeeksWithinBuffer;
     uint32_t            mSeeksOutsideBuffer;
     uint32_t            mBufferReadUponSeek;
     uint32_t            mBufferUnreadUponSeek;
     uint32_t            mBytesReadFromBuffer;
     uint32_t            mBigSeekIndex;
     struct {
         int64_t         mOldOffset;
         int64_t         mNewOffset;
     } mBigSeek[MAX_BIG_SEEKS];
 } bufstats;
 #else
 # define METER(x)       /* nothing */
 #endif
 using namespace mozilla::ipc;
 ////////////////////////////////////////////////////////////////////////////////
 // nsBufferedStream
 nsBufferedStream::nsBufferedStream()
     : mBuffer(nullptr),
       mBufferStartOffset(0),
       mCursor(0),
       mFillPoint(0),
       mStream(nullptr),
       mBufferDisabled(false),
       mEOF(false),
       mGetBufferCount(0)
 {
 }
 nsBufferedStream::~nsBufferedStream()
 {
     Close();
 }
 NS_IMPL_ISUPPORTS(nsBufferedStream, nsISeekableStream)
 nsresult
 nsBufferedStream::Init(nsISupports* stream, uint32_t bufferSize)
 {
     NS_ASSERTION(stream, "need to supply a stream");
     NS_ASSERTION(mStream == nullptr, "already inited");
     mStream = stream;
     NS_IF_ADDREF(mStream);
     mBufferSize = bufferSize;
     mBufferStartOffset = 0;
     mCursor = 0;
     const mozilla::fallible_t fallible = mozilla::fallible_t();
     mBuffer = new (fallible) char[bufferSize];
     if (mBuffer == nullptr)
         return NS_ERROR_OUT_OF_MEMORY;
     return NS_OK;
 }
 nsresult
 nsBufferedStream::Close()
 {
     NS_IF_RELEASE(mStream);
     if (mBuffer) {
         delete[] mBuffer;
         mBuffer = nullptr;
         mBufferSize = 0;
         mBufferStartOffset = 0;
         mCursor = 0;
         mFillPoint = 0;
     }
 #ifdef METERING
     {
         static FILE *tfp;
         if (!tfp) {
             tfp = fopen("/tmp/bufstats", "w");
             if (tfp)
                 setvbuf(tfp, nullptr, _IOLBF, 0);
         }
         if (tfp) {
             fprintf(tfp, "seeks within buffer:    %u\n",
                     bufstats.mSeeksWithinBuffer);
             fprintf(tfp, "seeks outside buffer:   %u\n",
                     bufstats.mSeeksOutsideBuffer);
             fprintf(tfp, "buffer read on seek:    %u\n",
                     bufstats.mBufferReadUponSeek);
             fprintf(tfp, "buffer unread on seek:  %u\n",
                     bufstats.mBufferUnreadUponSeek);
             fprintf(tfp, "bytes read from buffer: %u\n",
                     bufstats.mBytesReadFromBuffer);
             for (uint32_t i = 0; i < bufstats.mBigSeekIndex; i++) {
                 fprintf(tfp, "bigseek[%u] = {old: %u, new: %u}\n",
                         i,
                         bufstats.mBigSeek[i].mOldOffset,
                         bufstats.mBigSeek[i].mNewOffset);
             }
         }
     }
 #endif
     return NS_OK;
 }
 NS_IMETHODIMP
 nsBufferedStream::Seek(int32_t whence, int64_t offset)
 {
     if (mStream == nullptr)
         return NS_BASE_STREAM_CLOSED;
     // If the underlying stream isn't a random access store, then fail early.
     // We could possibly succeed for the case where the seek position denotes
     // something that happens to be read into the buffer, but that would make
     // the failure data-dependent.
     nsresult rv;
     nsCOMPtr<nsISeekableStream> ras = do_QueryInterface(mStream, &rv);
     if (NS_FAILED(rv)) return rv;
     int64_t absPos = 0;
     switch (whence) {
       case nsISeekableStream::NS_SEEK_SET:
         absPos = offset;
         break;
       case nsISeekableStream::NS_SEEK_CUR:
         absPos = mBufferStartOffset;
         absPos += mCursor;
         absPos += offset;
         break;
       case nsISeekableStream::NS_SEEK_END:
         absPos = -1;
         break;
       default:
         NS_NOTREACHED("bogus seek whence parameter");
         return NS_ERROR_UNEXPECTED;
     }
     // Let mCursor point into the existing buffer if the new position is
     // between the current cursor and the mFillPoint "fencepost" -- the
     // client may never get around to a Read or Write after this Seek.
     // Read and Write worry about flushing and filling in that event.
     // But if we're at EOF, make sure to pass the seek through to the
     // underlying stream, because it may have auto-closed itself and
     // needs to reopen.
     uint32_t offsetInBuffer = uint32_t(absPos - mBufferStartOffset);
     if (offsetInBuffer <= mFillPoint && !mEOF) {
         METER(bufstats.mSeeksWithinBuffer++);
         mCursor = offsetInBuffer;
         return NS_OK;
     }
     METER(bufstats.mSeeksOutsideBuffer++);
     METER(bufstats.mBufferReadUponSeek += mCursor);
     METER(bufstats.mBufferUnreadUponSeek += mFillPoint - mCursor);
     rv = Flush();
     if (NS_FAILED(rv)) return rv;
     rv = ras->Seek(whence, offset);
     if (NS_FAILED(rv)) return rv;
     mEOF = false;
     // Recompute whether the offset we're seeking to is in our buffer.
     // Note that we need to recompute because Flush() might have
     // changed mBufferStartOffset.
     offsetInBuffer = uint32_t(absPos - mBufferStartOffset);
     if (offsetInBuffer <= mFillPoint) {
         // It's safe to just set mCursor to offsetInBuffer.  In particular, we
         // want to avoid calling Fill() here since we already have the data that
         // was seeked to and calling Fill() might auto-close our underlying
         // stream in some cases.
         mCursor = offsetInBuffer;
         return NS_OK;
     }
     METER(if (bufstats.mBigSeekIndex < MAX_BIG_SEEKS)
               bufstats.mBigSeek[bufstats.mBigSeekIndex].mOldOffset =
                   mBufferStartOffset + int64_t(mCursor));
     const int64_t minus1 = -1;
     if (absPos == minus1) {
         // then we had the SEEK_END case, above
         int64_t tellPos;
         rv = ras->Tell(&tellPos);
         mBufferStartOffset = tellPos;
         if (NS_FAILED(rv)) return rv;
     }
     else {
         mBufferStartOffset = absPos;
     }
     METER(if (bufstats.mBigSeekIndex < MAX_BIG_SEEKS)
               bufstats.mBigSeek[bufstats.mBigSeekIndex++].mNewOffset =
                   mBufferStartOffset);
     mFillPoint = mCursor = 0;
     return Fill();
 }
 NS_IMETHODIMP
 nsBufferedStream::Tell(int64_t *result)
 {
     if (mStream == nullptr)
         return NS_BASE_STREAM_CLOSED;
     int64_t result64 = mBufferStartOffset;
     result64 += mCursor;
     *result = result64;
     return NS_OK;
 }
 NS_IMETHODIMP
 nsBufferedStream::SetEOF()
 {
     if (mStream == nullptr)
         return NS_BASE_STREAM_CLOSED;
     nsresult rv;
     nsCOMPtr<nsISeekableStream> ras = do_QueryInterface(mStream, &rv);
     if (NS_FAILED(rv)) return rv;
     rv = ras->SetEOF();
     if (NS_SUCCEEDED(rv))
         mEOF = true;
     return rv;
 }
 ////////////////////////////////////////////////////////////////////////////////
 // nsBufferedInputStream
 NS_IMPL_ADDREF_INHERITED(nsBufferedInputStream, nsBufferedStream)
 NS_IMPL_RELEASE_INHERITED(nsBufferedInputStream, nsBufferedStream)
 NS_IMPL_CLASSINFO(nsBufferedInputStream, nullptr, nsIClassInfo::THREADSAFE,
                   NS_BUFFEREDINPUTSTREAM_CID)
 NS_INTERFACE_MAP_BEGIN(nsBufferedInputStream)
     NS_INTERFACE_MAP_ENTRY(nsIInputStream)
     NS_INTERFACE_MAP_ENTRY(nsIBufferedInputStream)
     NS_INTERFACE_MAP_ENTRY(nsIStreamBufferAccess)
     NS_INTERFACE_MAP_ENTRY(nsIIPCSerializableInputStream)
     NS_IMPL_QUERY_CLASSINFO(nsBufferedInputStream)
 NS_INTERFACE_MAP_END_INHERITING(nsBufferedStream)
 NS_IMPL_CI_INTERFACE_GETTER(nsBufferedInputStream,
                             nsIInputStream,
                             nsIBufferedInputStream,
                             nsISeekableStream,
                             nsIStreamBufferAccess)
 nsresult
 nsBufferedInputStream::Create(nsISupports *aOuter, REFNSIID aIID, void **aResult)
 {
     NS_ENSURE_NO_AGGREGATION(aOuter);
     nsBufferedInputStream* stream = new nsBufferedInputStream();
     if (stream == nullptr)
         return NS_ERROR_OUT_OF_MEMORY;
     NS_ADDREF(stream);
     nsresult rv = stream->QueryInterface(aIID, aResult);
     NS_RELEASE(stream);
     return rv;
 }
 NS_IMETHODIMP
 nsBufferedInputStream::Init(nsIInputStream* stream, uint32_t bufferSize)
 {
     return nsBufferedStream::Init(stream, bufferSize);
 }
 NS_IMETHODIMP
 nsBufferedInputStream::Close()
 {
     nsresult rv1 = NS_OK, rv2;
     if (mStream) {
         rv1 = Source()->Close();
         NS_RELEASE(mStream);
     }
     rv2 = nsBufferedStream::Close();
     if (NS_FAILED(rv1)) return rv1;
     return rv2;
 }
 NS_IMETHODIMP
 nsBufferedInputStream::Available(uint64_t *result)
 {
     nsresult rv = NS_OK;
     *result = 0;
     if (mStream) {
         rv = Source()->Available(result);
     }
     *result += (mFillPoint - mCursor);
     return rv;
 }
 NS_IMETHODIMP
 nsBufferedInputStream::Read(char * buf, uint32_t count, uint32_t *result)
 {
     if (mBufferDisabled) {
         if (!mStream) {
             *result = 0;
             return NS_OK;
         }
         nsresult rv = Source()->Read(buf, count, result);
         if (NS_SUCCEEDED(rv)) {
             mBufferStartOffset += *result;  // so nsBufferedStream::Tell works
             if (*result == 0) {
                 mEOF = true;
             }
         }
         return rv;
     }
     return ReadSegments(NS_CopySegmentToBuffer, buf, count, result);
 }
 NS_IMETHODIMP
 nsBufferedInputStream::ReadSegments(nsWriteSegmentFun writer, void *closure,
                                     uint32_t count, uint32_t *result)
 {
     *result = 0;
     if (!mStream)
         return NS_OK;
     nsresult rv = NS_OK;
     while (count > 0) {
         uint32_t amt = std::min(count, mFillPoint - mCursor);
         if (amt > 0) {
             uint32_t read = 0;
             rv = writer(this, closure, mBuffer + mCursor, *result, amt, &read);
             if (NS_FAILED(rv)) {
                 // errors returned from the writer end here!
                 rv = NS_OK;
                 break;
             }
             *result += read;
             count -= read;
             mCursor += read;
         }
         else {
             rv = Fill();
             if (NS_FAILED(rv) || mFillPoint == mCursor)
                 break;
         }
     }
     return (*result > 0) ? NS_OK : rv;
 }
 NS_IMETHODIMP
 nsBufferedInputStream::IsNonBlocking(bool *aNonBlocking)
 {
     if (mStream)
         return Source()->IsNonBlocking(aNonBlocking);
     return NS_ERROR_NOT_INITIALIZED;
 }
 NS_IMETHODIMP
 nsBufferedInputStream::Fill()
 {
     if (mBufferDisabled)
         return NS_OK;
     NS_ENSURE_TRUE(mStream, NS_ERROR_NOT_INITIALIZED);
     nsresult rv;
     int32_t rem = int32_t(mFillPoint - mCursor);
     if (rem > 0) {
         // slide the remainder down to the start of the buffer
         // |<------------->|<--rem-->|<--->|
         // b               c         f     s
         memcpy(mBuffer, mBuffer + mCursor, rem);
     }
     mBufferStartOffset += mCursor;
     mFillPoint = rem;
     mCursor = 0;
     uint32_t amt;
     rv = Source()->Read(mBuffer + mFillPoint, mBufferSize - mFillPoint, &amt);
     if (NS_FAILED(rv)) return rv;
     if (amt == 0)
         mEOF = true;
     mFillPoint += amt;
     return NS_OK;
 }
 NS_IMETHODIMP_(char*)
 nsBufferedInputStream::GetBuffer(uint32_t aLength, uint32_t aAlignMask)
 {
     NS_ASSERTION(mGetBufferCount == 0, "nested GetBuffer!");
     if (mGetBufferCount != 0)
         return nullptr;
     if (mBufferDisabled)
         return nullptr;
     char* buf = mBuffer + mCursor;
     uint32_t rem = mFillPoint - mCursor;
     if (rem == 0) {
         if (NS_FAILED(Fill()))
             return nullptr;
         buf = mBuffer + mCursor;
         rem = mFillPoint - mCursor;
     }
     uint32_t mod = (NS_PTR_TO_INT32(buf) & aAlignMask);
     if (mod) {
         uint32_t pad = aAlignMask + 1 - mod;
         if (pad > rem)
             return nullptr;
         memset(buf, 0, pad);
         mCursor += pad;
         buf += pad;
         rem -= pad;
     }
     if (aLength > rem)
         return nullptr;
     mGetBufferCount++;
     return buf;
 }
 NS_IMETHODIMP_(void)
 nsBufferedInputStream::PutBuffer(char* aBuffer, uint32_t aLength)
 {
     NS_ASSERTION(mGetBufferCount == 1, "stray PutBuffer!");
     if (--mGetBufferCount != 0)
         return;
     NS_ASSERTION(mCursor + aLength <= mFillPoint, "PutBuffer botch");
     mCursor += aLength;
 }
 NS_IMETHODIMP
 nsBufferedInputStream::DisableBuffering()
 {
     NS_ASSERTION(!mBufferDisabled, "redundant call to DisableBuffering!");
     NS_ASSERTION(mGetBufferCount == 0,
                  "DisableBuffer call between GetBuffer and PutBuffer!");
     if (mGetBufferCount != 0)
         return NS_ERROR_UNEXPECTED;
     // Empty the buffer so nsBufferedStream::Tell works.
     mBufferStartOffset += mCursor;
     mFillPoint = mCursor = 0;
     mBufferDisabled = true;
     return NS_OK;
 }
 NS_IMETHODIMP
 nsBufferedInputStream::EnableBuffering()
 {
     NS_ASSERTION(mBufferDisabled, "gratuitous call to EnableBuffering!");
     mBufferDisabled = false;
     return NS_OK;
 }
 NS_IMETHODIMP
 nsBufferedInputStream::GetUnbufferedStream(nsISupports* *aStream)
 {
     // Empty the buffer so subsequent i/o trumps any buffered data.
     mBufferStartOffset += mCursor;
     mFillPoint = mCursor = 0;
     *aStream = mStream;
     NS_IF_ADDREF(*aStream);
     return NS_OK;
 }
 void
 nsBufferedInputStream::Serialize(InputStreamParams& aParams,
                                  FileDescriptorArray& aFileDescriptors)
 {
     BufferedInputStreamParams params;
     if (mStream) {
         nsCOMPtr<nsIInputStream> stream = do_QueryInterface(mStream);
         MOZ_ASSERT(stream);
         InputStreamParams wrappedParams;
         SerializeInputStream(stream, wrappedParams, aFileDescriptors);
         params.optionalStream() = wrappedParams;
     }
     else {
         params.optionalStream() = mozilla::void_t();
     }
     params.bufferSize() = mBufferSize;
     aParams = params;
 }
 bool
 nsBufferedInputStream::Deserialize(const InputStreamParams& aParams,
                                    const FileDescriptorArray& aFileDescriptors)
 {
     if (aParams.type() != InputStreamParams::TBufferedInputStreamParams) {
         NS_ERROR("Received unknown parameters from the other process!");
         return false;
     }
     const BufferedInputStreamParams& params =
         aParams.get_BufferedInputStreamParams();
     const OptionalInputStreamParams& wrappedParams = params.optionalStream();
     nsCOMPtr<nsIInputStream> stream;
     if (wrappedParams.type() == OptionalInputStreamParams::TInputStreamParams) {
         stream = DeserializeInputStream(wrappedParams.get_InputStreamParams(),
                                         aFileDescriptors);
         if (!stream) {
             NS_WARNING("Failed to deserialize wrapped stream!");
             return false;
         }
     }
     else {
         NS_ASSERTION(wrappedParams.type() == OptionalInputStreamParams::Tvoid_t,
                      "Unknown type for OptionalInputStreamParams!");
     }
     nsresult rv = Init(stream, params.bufferSize());
     NS_ENSURE_SUCCESS(rv, false);
     return true;
 }
 ////////////////////////////////////////////////////////////////////////////////
 // nsBufferedOutputStream
 NS_IMPL_ADDREF_INHERITED(nsBufferedOutputStream, nsBufferedStream)
 NS_IMPL_RELEASE_INHERITED(nsBufferedOutputStream, nsBufferedStream)
 // This QI uses NS_INTERFACE_MAP_ENTRY_CONDITIONAL to check for
 // non-nullness of mSafeStream.
 NS_INTERFACE_MAP_BEGIN(nsBufferedOutputStream)
     NS_INTERFACE_MAP_ENTRY(nsIOutputStream)
     NS_INTERFACE_MAP_ENTRY_CONDITIONAL(nsISafeOutputStream, mSafeStream)
     NS_INTERFACE_MAP_ENTRY(nsIBufferedOutputStream)
     NS_INTERFACE_MAP_ENTRY(nsIStreamBufferAccess)
 NS_INTERFACE_MAP_END_INHERITING(nsBufferedStream)
 nsresult
 nsBufferedOutputStream::Create(nsISupports *aOuter, REFNSIID aIID, void **aResult)
 {
     NS_ENSURE_NO_AGGREGATION(aOuter);
     nsBufferedOutputStream* stream = new nsBufferedOutputStream();
     if (stream == nullptr)
         return NS_ERROR_OUT_OF_MEMORY;
     NS_ADDREF(stream);
     nsresult rv = stream->QueryInterface(aIID, aResult);
     NS_RELEASE(stream);
     return rv;
 }
 NS_IMETHODIMP
 nsBufferedOutputStream::Init(nsIOutputStream* stream, uint32_t bufferSize)
 {
     // QI stream to an nsISafeOutputStream, to see if we should support it
     mSafeStream = do_QueryInterface(stream);
     return nsBufferedStream::Init(stream, bufferSize);
 }
 NS_IMETHODIMP
 nsBufferedOutputStream::Close()
 {
     nsresult rv1, rv2 = NS_OK, rv3;
     rv1 = Flush();
     // If we fail to Flush all the data, then we close anyway and drop the
     // remaining data in the buffer. We do this because it's what Unix does
     // for fclose and close. However, we report the error from Flush anyway.
     if (mStream) {
         rv2 = Sink()->Close();
         NS_RELEASE(mStream);
     }
     rv3 = nsBufferedStream::Close();
     if (NS_FAILED(rv1)) return rv1;
     if (NS_FAILED(rv2)) return rv2;
     return rv3;
 }
 NS_IMETHODIMP
 nsBufferedOutputStream::Write(const char *buf, uint32_t count, uint32_t *result)
 {
     nsresult rv = NS_OK;
     uint32_t written = 0;
     while (count > 0) {
         uint32_t amt = std::min(count, mBufferSize - mCursor);
         if (amt > 0) {
             memcpy(mBuffer + mCursor, buf + written, amt);
             written += amt;
             count -= amt;
             mCursor += amt;
             if (mFillPoint < mCursor)
                 mFillPoint = mCursor;
         }
         else {
             NS_ASSERTION(mFillPoint, "iloop in nsBufferedOutputStream::Write!");
             rv = Flush();
             if (NS_FAILED(rv)) break;
         }
     }
     *result = written;
     return (written > 0) ? NS_OK : rv;
 }
 NS_IMETHODIMP
 nsBufferedOutputStream::Flush()
 {
     nsresult rv;
     uint32_t amt;
     if (!mStream) {
         // Stream already cancelled/flushed; probably because of previous error.
         return NS_OK;
     }
     rv = Sink()->Write(mBuffer, mFillPoint, &amt);
     if (NS_FAILED(rv)) return rv;
     mBufferStartOffset += amt;
     if (amt == mFillPoint) {
         mFillPoint = mCursor = 0;
         return NS_OK;   // flushed everything
     }
     // slide the remainder down to the start of the buffer
     // |<-------------->|<---|----->|
     // b                a    c      s
     uint32_t rem = mFillPoint - amt;
     memcpy(mBuffer, mBuffer + amt, rem);
     mFillPoint = mCursor = rem;
     return NS_ERROR_FAILURE;        // didn't flush all
 }
 // nsISafeOutputStream
 NS_IMETHODIMP
 nsBufferedOutputStream::Finish()
 {
     // flush the stream, to write out any buffered data...
     nsresult rv = nsBufferedOutputStream::Flush();
     if (NS_FAILED(rv))
         NS_WARNING("failed to flush buffered data! possible dataloss");
     // ... and finish the underlying stream...
     if (NS_SUCCEEDED(rv))
         rv = mSafeStream->Finish();
     else
         Sink()->Close();
     // ... and close the buffered stream, so any further attempts to flush/close
     // the buffered stream won't cause errors.
     nsBufferedStream::Close();
     return rv;
 }
 static NS_METHOD
 nsReadFromInputStream(nsIOutputStream* outStr,
                       void* closure,
                       char* toRawSegment,
                       uint32_t offset,
                       uint32_t count,
                       uint32_t *readCount)
 {
     nsIInputStream* fromStream = (nsIInputStream*)closure;
     return fromStream->Read(toRawSegment, count, readCount);
 }
 NS_IMETHODIMP
 nsBufferedOutputStream::WriteFrom(nsIInputStream *inStr, uint32_t count, uint32_t *_retval)
 {
     return WriteSegments(nsReadFromInputStream, inStr, count, _retval);
 }
 NS_IMETHODIMP
 nsBufferedOutputStream::WriteSegments(nsReadSegmentFun reader, void * closure, uint32_t count, uint32_t *_retval)
 {
     *_retval = 0;
     nsresult rv;
     while (count > 0) {
         uint32_t left = std::min(count, mBufferSize - mCursor);
         if (left == 0) {
             rv = Flush();
             if (NS_FAILED(rv))
               return rv;
             continue;
         }
         uint32_t read = 0;
         rv = reader(this, closure, mBuffer + mCursor, *_retval, left, &read);
         if (NS_FAILED(rv)) // If we have written some data, return ok
             return (*_retval > 0) ? NS_OK : rv;
         mCursor += read;
         *_retval += read;
         count -= read;
         mFillPoint = std::max(mFillPoint, mCursor);
     }
     return NS_OK;
 }
 NS_IMETHODIMP
 nsBufferedOutputStream::IsNonBlocking(bool *aNonBlocking)
 {
     if (mStream)
         return Sink()->IsNonBlocking(aNonBlocking);
     return NS_ERROR_NOT_INITIALIZED;
 }
 NS_IMETHODIMP_(char*)
 nsBufferedOutputStream::GetBuffer(uint32_t aLength, uint32_t aAlignMask)
 {
     NS_ASSERTION(mGetBufferCount == 0, "nested GetBuffer!");
     if (mGetBufferCount != 0)
         return nullptr;
     if (mBufferDisabled)
         return nullptr;
     char* buf = mBuffer + mCursor;
     uint32_t rem = mBufferSize - mCursor;
     if (rem == 0) {
         if (NS_FAILED(Flush()))
             return nullptr;
         buf = mBuffer + mCursor;
         rem = mBufferSize - mCursor;
     }
     uint32_t mod = (NS_PTR_TO_INT32(buf) & aAlignMask);
     if (mod) {
         uint32_t pad = aAlignMask + 1 - mod;
         if (pad > rem)
             return nullptr;
         memset(buf, 0, pad);
         mCursor += pad;
         buf += pad;
         rem -= pad;
     }
     if (aLength > rem)
         return nullptr;
     mGetBufferCount++;
     return buf;
 }
 NS_IMETHODIMP_(void)
 nsBufferedOutputStream::PutBuffer(char* aBuffer, uint32_t aLength)
 {
     NS_ASSERTION(mGetBufferCount == 1, "stray PutBuffer!");
     if (--mGetBufferCount != 0)
         return;
     NS_ASSERTION(mCursor + aLength <= mBufferSize, "PutBuffer botch");
     mCursor += aLength;
     if (mFillPoint < mCursor)
         mFillPoint = mCursor;
 }
 NS_IMETHODIMP
 nsBufferedOutputStream::DisableBuffering()
 {
     NS_ASSERTION(!mBufferDisabled, "redundant call to DisableBuffering!");
     NS_ASSERTION(mGetBufferCount == 0,
                  "DisableBuffer call between GetBuffer and PutBuffer!");
     if (mGetBufferCount != 0)
         return NS_ERROR_UNEXPECTED;
     // Empty the buffer so nsBufferedStream::Tell works.
     nsresult rv = Flush();
     if (NS_FAILED(rv))
         return rv;
     mBufferDisabled = true;
     return NS_OK;
 }
 NS_IMETHODIMP
 nsBufferedOutputStream::EnableBuffering()
 {
     NS_ASSERTION(mBufferDisabled, "gratuitous call to EnableBuffering!");
     mBufferDisabled = false;
     return NS_OK;
 }
 NS_IMETHODIMP
 nsBufferedOutputStream::GetUnbufferedStream(nsISupports* *aStream)
 {
     // Empty the buffer so subsequent i/o trumps any buffered data.
     if (mFillPoint) {
         nsresult rv = Flush();
         if (NS_FAILED(rv))
             return rv;
     }
     *aStream = mStream;
     NS_IF_ADDREF(*aStream);
     return NS_OK;
 }
 ////////////////////////////////////////////////////////////////////////////////

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netwerk/base/src/nsBufferedStreams.cpp@6474c204b198 (annotated)

netwerk/base/src/nsBufferedStreams.cpp