QLocalSocket/Win: reimplement skipData() function

The base implementation discards the data by reading into a dummy
buffer, which is slower than necessary.

Change-Id: Iabf0c4a25746af6cac5b61d7bda66d89501c808c
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@gmx.de>

2 files changed, 20 insertions, 0 deletions

diff --git a/src/corelib/io/qwindowspipereader.cpp b/src/corelib/io/qwindowspipereader.cpp
index c3ac51df94..5415ad7830 100644
--- a/src/corelib/io/qwindowspipereader.cpp
+++ b/src/corelib/io/qwindowspipereader.cpp
@@ -233,6 +233,25 @@ qint64 QWindowsPipeReader::readLine(char *data, qint64 maxlen)
 }
 
 /*!
+    Skips up to \c{maxlen} bytes from the internal read buffer.
+ */
+qint64 QWindowsPipeReader::skip(qint64 maxlen)
+{
+    QMutexLocker locker(&mutex);
+
+    const qint64 skippedSoFar = readBuffer.skip(qMin(actualReadBufferSize, maxlen));
+    actualReadBufferSize -= skippedSoFar;
+
+    if (!pipeBroken) {
+        startAsyncReadHelper(&locker);
+        if (skippedSoFar == 0)
+            return -2;      // signal EWOULDBLOCK
+    }
+
+    return skippedSoFar;
+}
+
+/*!
     Returns \c true if a complete line of data can be read from the buffer.
  */
 bool QWindowsPipeReader::canReadLine() const
diff --git a/src/corelib/io/qwindowspipereader_p.h b/src/corelib/io/qwindowspipereader_p.h
index e2190d67d9..5eb62cb393 100644
--- a/src/corelib/io/qwindowspipereader_p.h
+++ b/src/corelib/io/qwindowspipereader_p.h
@@ -79,6 +79,7 @@ public:
     qint64 bytesAvailable() const;
     qint64 read(char *data, qint64 maxlen);
     qint64 readLine(char *data, qint64 maxlen);
+    qint64 skip(qint64 maxlen);
     bool canReadLine() const;
     DWORD checkPipeState();
     bool checkForReadyRead() { return consumePendingAndEmit(false); }