QProcess: allow merged channels forwarding for detached processes

[ChangeLog][QtCore][QProcess] Added support for QProcess::MergedChannels
mode with startDetached().

Change-Id: I953ad2063322015332269522a297f8e2842e438c
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@gmx.de>

src/corelib/io/qprocess.cpp

@@ -616,7 +616,8 @@ void QProcessPrivate::Channel::clear()
     process into the standard output channel (\c stdout). The
     standard error channel (\c stderr) will not receive any data. The
     standard output and standard error data of the running process
-    are interleaved.
+    are interleaved. For detached processes, the merged output of the
+    running process is forwarded onto the main process.
 
     \value ForwardedChannels QProcess forwards the output of the
     running process onto the main process. Anything the child process
@@ -1000,10 +1001,11 @@ bool QProcessPrivate::openChannelsForDetached()
         return false;
 
     // stderr channel.
-    if (processChannelMode == QProcess::MergedChannels || (stderrChannel.type != Channel::Normal
+    if (stderrChannel.type != Channel::Normal
             && (stderrChannel.type != Channel::Redirect
                 || processChannelMode == QProcess::ForwardedChannels
-                || processChannelMode == QProcess::ForwardedErrorChannel))) {
+                || processChannelMode == QProcess::ForwardedErrorChannel
+                || processChannelMode == QProcess::MergedChannels)) {
         qWarning("QProcess::openChannelsForDetached: Inconsistent stderr channel configuration");
     }
     if (stderrChannel.type == Channel::Redirect && !openChannel(stderrChannel))
@@ -2172,6 +2174,7 @@ void QProcess::startCommand(const QString &command, OpenMode mode)
     \li setStandardErrorFile()
     \li setStandardInputFile()
     \li setStandardOutputFile()
+    \li setProcessChannelMode(QProcess::MergedChannels)
     \li setWorkingDirectory()
     \endlist
     All other properties of the QProcess object are ignored.

src/corelib/io/qprocess_p.h

@@ -319,6 +319,9 @@ public:
     bool openChannels();
     bool openChannelsForDetached();
     bool openChannel(Channel &channel);
+#if defined(Q_OS_UNIX)
+    void commitChannels();
+#endif
     void closeChannel(Channel *channel);
     void closeWriteChannel();
     bool tryReadFromChannel(Channel *channel); // obviously, only stdout and stderr

src/corelib/io/qprocess_unix.cpp

@@ -319,6 +319,24 @@ bool QProcessPrivate::openChannel(Channel &channel)
     }
 }
 
+void QProcessPrivate::commitChannels()
+{
+    // copy the stdin socket if asked to (without closing on exec)
+    if (stdinChannel.pipe[0] != INVALID_Q_PIPE)
+        qt_safe_dup2(stdinChannel.pipe[0], STDIN_FILENO, 0);
+
+    // copy the stdout and stderr if asked to
+    if (stdoutChannel.pipe[1] != INVALID_Q_PIPE)
+        qt_safe_dup2(stdoutChannel.pipe[1], STDOUT_FILENO, 0);
+    if (stderrChannel.pipe[1] != INVALID_Q_PIPE) {
+        qt_safe_dup2(stderrChannel.pipe[1], STDERR_FILENO, 0);
+    } else {
+        // merge stdout and stderr if asked to
+        if (processChannelMode == QProcess::MergedChannels)
+            qt_safe_dup2(STDOUT_FILENO, STDERR_FILENO, 0);
+    }
+}
+
 static char **_q_dupEnvironment(const QProcessEnvironmentPrivate::Map &environment, int *envc)
 {
     *envc = 0;
@@ -525,20 +543,8 @@ void QProcessPrivate::execChild(const char *workingDir, char **argv, char **envp
 
     ChildError error = { 0, {} };       // force zeroing of function[8]
 
-    // copy the stdin socket if asked to (without closing on exec)
+    // Render channels configuration.
-    if (stdinChannel.pipe[0] != INVALID_Q_PIPE)
+    commitChannels();
-        qt_safe_dup2(stdinChannel.pipe[0], STDIN_FILENO, 0);
-
-    // copy the stdout and stderr if asked to
-    if (stdoutChannel.pipe[1] != INVALID_Q_PIPE)
-        qt_safe_dup2(stdoutChannel.pipe[1], STDOUT_FILENO, 0);
-    if (stderrChannel.pipe[1] != INVALID_Q_PIPE) {
-        qt_safe_dup2(stderrChannel.pipe[1], STDERR_FILENO, 0);
-    } else {
-        // merge stdout and stderr if asked to
-        if (processChannelMode == QProcess::MergedChannels)
-            qt_safe_dup2(STDOUT_FILENO, STDERR_FILENO, 0);
-    }
 
     // make sure this fd is closed if execv() succeeds
     qt_safe_close(childStartedPipe[0]);
@@ -901,15 +907,8 @@ bool QProcessPrivate::startDetached(qint64 *pid)
         if (doubleForkPid == 0) {
             qt_safe_close(pidPipe[1]);
 
-            // copy the stdin socket if asked to (without closing on exec)
+            // Render channels configuration.
-            if (stdinChannel.type == Channel::Redirect)
+            commitChannels();
-                qt_safe_dup2(stdinChannel.pipe[0], STDIN_FILENO, 0);
-
-            // copy the stdout and stderr if asked to
-            if (stdoutChannel.type == Channel::Redirect)
-                qt_safe_dup2(stdoutChannel.pipe[1], STDOUT_FILENO, 0);
-            if (stderrChannel.type == Channel::Redirect)
-                qt_safe_dup2(stderrChannel.pipe[1], STDERR_FILENO, 0);
 
             if (!encodedWorkingDirectory.isEmpty()) {
                 if (QT_CHDIR(encodedWorkingDirectory.constData()) == -1)

src/corelib/io/qprocess_win.cpp

@@ -914,17 +914,7 @@ bool QProcessPrivate::startDetached(qint64 *pid)
 
     DWORD dwCreationFlags = (GetConsoleWindow() ? 0 : CREATE_NO_WINDOW);
     dwCreationFlags |= CREATE_UNICODE_ENVIRONMENT;
-    STARTUPINFOW startupInfo = { sizeof( STARTUPINFO ), 0, 0, 0,
+    STARTUPINFOW startupInfo = createStartupInfo();
-                                 (ulong)CW_USEDEFAULT, (ulong)CW_USEDEFAULT,
-                                 (ulong)CW_USEDEFAULT, (ulong)CW_USEDEFAULT,
-                                 0, 0, 0,
-                                 STARTF_USESTDHANDLES,
-                                 0, 0, 0,
-                                 pipeOrStdHandle(stdinChannel.pipe[0], STD_INPUT_HANDLE),
-                                 pipeOrStdHandle(stdoutChannel.pipe[1], STD_OUTPUT_HANDLE),
-                                 pipeOrStdHandle(stderrChannel.pipe[1], STD_ERROR_HANDLE)
-                               };
-
     QProcess::CreateProcessArguments cpargs = {
         nullptr, reinterpret_cast<wchar_t *>(const_cast<ushort *>(args.utf16())),
         nullptr, nullptr, true, dwCreationFlags, envPtr,

tests/auto/corelib/io/qprocess/testForwardingHelper/main.cpp

@@ -36,8 +36,8 @@ int main(int argc, char *argv[])
         return 1;
     }
     fputs("out data", stdout);
-    fputs("err data", stderr);
     fflush(stdout);
+    fputs("err data", stderr);
     fflush(stderr);
     std::ofstream out(argv[1]);
     out << "That's all folks!";

tests/auto/corelib/io/qprocess/tst_qprocess.cpp

@@ -1125,6 +1125,10 @@ void tst_QProcess::forwardedChannels_data()
             << true
             << int(QProcess::SeparateChannels) << int(QProcess::ManagedInputChannel)
             << QByteArray("out data") << QByteArray("err data");
+    QTest::newRow("detached-merged-forwarding")
+            << true
+            << int(QProcess::MergedChannels) << int(QProcess::ManagedInputChannel)
+            << QByteArray("out data" "err data") << QByteArray();
 }
 
 void tst_QProcess::forwardedChannels()