Utils: Add a QtcProcess flag to keep stdin open

Needed to run e.g. gdb on-device.

Change-Id: I5a98df575478f18adf1540ced44f6808bdba0b76
Reviewed-by: Christian Stenger <christian.stenger@qt.io>

src/libs/utils/qtcprocess.cpp

@@ -128,6 +128,7 @@ public:
 
     bool m_lowPriority = false;
     bool m_disableUnixTerminal = false;
+    bool m_keepStdInOpen = false;
 };
 
 class QtcProcessPrivate : public QObject
@@ -433,6 +434,16 @@ void QtcProcess::setDisableUnixTerminal()
     d->m_process->m_disableUnixTerminal = true;
 }
 
+void QtcProcess::setKeepWriteChannelOpen()
+{
+    d->m_process->m_keepStdInOpen = true;
+}
+
+bool QtcProcess::keepsWriteChannelOpen() const
+{
+    return d->m_process->m_keepStdInOpen;
+}
+
 void QtcProcess::setRemoteProcessHooks(const DeviceProcessHooks &hooks)
 {
     s_deviceHooks = hooks;

src/libs/utils/qtcprocess.h

@@ -173,6 +173,9 @@ public:
     void closeWriteChannel();
     void close();
 
+    void setKeepWriteChannelOpen();
+    bool keepsWriteChannelOpen() const;
+
 signals:
     void started();
     void finished();

src/plugins/debugger/gdb/gdbengine.cpp

@@ -3851,6 +3851,7 @@ void GdbEngine::setupEngine()
     if (QFileInfo(rp.debugger.workingDirectory).isDir())
         m_gdbProc.setWorkingDirectory(rp.debugger.workingDirectory);
     m_gdbProc.setEnvironment(gdbEnv);
+    m_gdbProc.setKeepWriteChannelOpen();
     m_gdbProc.start();
 
     if (!m_gdbProc.waitForStarted()) {

src/plugins/docker/dockerdevice.cpp

@@ -946,6 +946,8 @@ void DockerDevice::runProcess(QtcProcess &process) const
 
     CommandLine cmd{"docker", {"exec"}};
     cmd.addArgs({"-w", workingDir.path()});
+    if (process.keepsWriteChannelOpen())
+        cmd.addArg("-i");
     cmd.addArg(d->m_container);
     cmd.addArg(origCmd.executable().path()); // Cut off the docker://.../ bits.
     cmd.addArgs(origCmd.splitArguments(osType()));