QProcess/Win: move pipe draining into QWindowsPipeReader

... where it belongs.

To avoid the loop, introduce the drainAndStop() function, which allows
QWindowsPipeReader to flush the pipe itself. It determines the number of
bytes pending and blocks until the remainder of the process output is
received.

Note that the loop in drainOutputPipes() didn't actually have to
interleave the two pipes (because we're presuming that the operations
will finish instantly), so we don't do it now. Also, the code violated
the API contract: 'true' was returned when the 'wrong' channel received
data; this is now fixed as a side effect.

Change-Id: I38ed4861a238e39e793c3716e856e5bfdeed3d74
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@gmx.de>

1 files changed, 7 insertions, 1 deletions

diff --git a/src/corelib/io/qwindowspipereader_p.h b/src/corelib/io/qwindowspipereader_p.h
index 2842343597..c61018d87d 100644
--- a/src/corelib/io/qwindowspipereader_p.h
+++ b/src/corelib/io/qwindowspipereader_p.h
@@ -68,6 +68,7 @@ public:
     void setHandle(HANDLE hPipeReadEnd);
     void startAsyncRead();
     void stop();
+    void drainAndStop();
 
     void setMaxReadBufferSize(qint64 size) { readBufferMaxSize = size; }
     qint64 maxReadBufferSize() const { return readBufferMaxSize; }
@@ -88,12 +89,15 @@ Q_SIGNALS:
     void _q_queueReadyRead(QPrivateSignal);
 
 private:
+    void startAsyncReadHelper(qint64 bytesToRead);
+    void cancelAsyncRead();
     static void CALLBACK readFileCompleted(DWORD errorCode, DWORD numberOfBytesTransfered,
                                            OVERLAPPED *overlappedBase);
     void notified(DWORD errorCode, DWORD numberOfBytesRead);
     DWORD checkPipeState();
     bool waitForNotification(int timeout);
     void emitPendingReadyRead();
+    void emitPipeClosed();
 
     class Overlapped : public OVERLAPPED
     {
@@ -109,7 +113,9 @@ private:
     qint64 readBufferMaxSize;
     QRingBuffer readBuffer;
     qint64 actualReadBufferSize;
-    bool stopped;
+    qint64 bytesPending;
+
+    enum State { Stopped, Running, Draining } state;
     bool readSequenceStarted;
     bool notifiedCalled;
     bool pipeBroken;