ConnectionClient: Fix unreliable sendEnd()

Calling QLocalSocket::flush() is not enough since it sends "as much as
possible from the internal write buffer" (doc), but not necessarily
everything.

Change-Id: Ica2220aaf9f8c01fe039c3b3b8e3ff7269c00851
Reviewed-by: Marco Bubke <marco.bubke@theqtcompany.com>

2 files changed, 14 insertions, 0 deletions

diff --git a/src/libs/codemodelbackendipc/connectionclient.cpp b/src/libs/codemodelbackendipc/connectionclient.cpp
index 2bac59585a..61c12e4629 100644
--- a/src/libs/codemodelbackendipc/connectionclient.cpp
+++ b/src/libs/codemodelbackendipc/connectionclient.cpp
@@ -92,10 +92,22 @@ bool ConnectionClient::isConnected() const
     return localSocket.state() == QLocalSocket::ConnectedState;
 }
 
+void ConnectionClient::waitUntilSocketIsFlushed() const
+{
+    // Avoid to call QAbstractSocket::waitForBytesWritten(), which is known to
+    // be unreliable on Windows. Instead, call processEvents() to actually send
+    // the data.
+    while (localSocket.bytesToWrite() > 0) {
+        QCoreApplication::processEvents();
+        QThread::msleep(20);
+    }
+}
+
 void ConnectionClient::sendEndCommand()
 {
     serverProxy_.end();
     localSocket.flush();
+    waitUntilSocketIsFlushed();
 }
 
 void ConnectionClient::resetProcessAliveTimer()
diff --git a/src/libs/codemodelbackendipc/connectionclient.h b/src/libs/codemodelbackendipc/connectionclient.h
index e118db7116..2e2cb2ef15 100644
--- a/src/libs/codemodelbackendipc/connectionclient.h
+++ b/src/libs/codemodelbackendipc/connectionclient.h
@@ -96,6 +96,8 @@ private:
     void disconnectProcessFinished() const;
     void connectStandardOutputAndError() const;
 
+    void waitUntilSocketIsFlushed() const;
+
 private:
     mutable std::unique_ptr<QProcess> process_;
     QLocalSocket localSocket;