void
nsPipe::AdvanceReadCursor(PRUint32 bytesRead)
{
NS_ASSERTION(bytesRead, "dont call if no bytes read");
nsPipeEvents events;
{
nsAutoMonitor mon(mMonitor);
LOG(("III advancing read cursor by %u\n", bytesRead));
NS_ASSERTION(bytesRead <= mBuffer.GetSegmentSize(), "read too much");
mReadCursor += bytesRead;
NS_ASSERTION(mReadCursor <= mReadLimit, "read cursor exceeds limit");
mInput.ReduceAvailable(bytesRead);
if (mReadCursor == mReadLimit) {
// we've reached the limit of how much we can read from this segment.
// if at the end of this segment, then we must discard this segment.
// if still writing in this segment then bail because we're not done
// with the segment and have to wait for now...
if (mWriteSegment == 0 && mWriteLimit > mWriteCursor) {
NS_ASSERTION(mReadLimit == mWriteCursor, "unexpected state");
return;
}
// shift write segment index (-1 indicates an empty buffer).
--mWriteSegment;
// done with this segment
mBuffer.DeleteFirstSegment();
LOG(("III deleting first segment\n"));
if (mWriteSegment == -1) {
// buffer is completely empty
mReadCursor = nsnull;
mReadLimit = nsnull;
mWriteCursor = nsnull;
mWriteLimit = nsnull;
}
else {
// advance read cursor and limit to next buffer segment
mReadCursor = mBuffer.GetSegment(0);
if (mWriteSegment == 0)
mReadLimit = mWriteCursor;
else
mReadLimit = mReadCursor + mBuffer.GetSegmentSize();
}
// we've free'd up a segment, so notify output stream that pipe has
// room for a new segment.
if (mOutput.OnOutputWritable(events))
mon.Notify();
}
}
}
