Allow qDebug output to be configured by qSetMessagePattern()

Add qSetMessagePattern() to configure the default
message pattern. This one can still be overwritten by setting the
QT_MESSAGE_PATTERN environment variable.

Without this method, there's actually no way to change the
default output programatically. Since QT_MESSAGE_PATTERN is
evaluated when the first message arrives, setting it via e.g. qputenv
might have no effect/be too late.

Change-Id: I115e0c30606f128fdbf5c169a951ffa2a6a48517
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

2 files changed, 41 insertions, 4 deletions

diff --git a/tests/auto/corelib/global/qlogging/app/main.cpp b/tests/auto/corelib/global/qlogging/app/main.cpp
index dfa52315c7..2f5a975e43 100644
--- a/tests/auto/corelib/global/qlogging/app/main.cpp
+++ b/tests/auto/corelib/global/qlogging/app/main.cpp
@@ -51,8 +51,15 @@ int main(int argc, char **argv)
     QCoreApplication app(argc, argv);
     app.setApplicationName("tst_qlogging");
 
+    qSetMessagePattern("[%{type}] %{message}");
+
     qDebug("qDebug");
     qWarning("qWarning");
     qCritical("qCritical");
+
+    qSetMessagePattern(QString());
+
+    qDebug("qDebug2");
+
     return 0;
 }
diff --git a/tests/auto/corelib/global/qlogging/tst_qlogging.cpp b/tests/auto/corelib/global/qlogging/tst_qlogging.cpp
index 1d6aa89035..5474b9aa3b 100644
--- a/tests/auto/corelib/global/qlogging/tst_qlogging.cpp
+++ b/tests/auto/corelib/global/qlogging/tst_qlogging.cpp
@@ -630,13 +630,16 @@ void tst_qmessagehandler::cleanupFuncinfo()
 void tst_qmessagehandler::qMessagePattern()
 {
     QProcess process;
+    const QString appExe = m_appDir + "/app";
 
+    //
+    // test QT_MESSAGE_PATTERN
+    //
     QStringList environment = QProcess::systemEnvironment();
     // %{file} is tricky because of shadow builds
     environment.prepend("QT_MESSAGE_PATTERN=\"%{type} %{appname} %{line} %{function} %{message}\"");
     process.setEnvironment(environment);
 
-    QString appExe = m_appDir + "/app";
     process.start(appExe);
     QVERIFY2(process.waitForStarted(), qPrintable(
         QString::fromLatin1("Could not start %1: %2").arg(appExe, process.errorString())));
@@ -649,9 +652,10 @@ void tst_qmessagehandler::qMessagePattern()
     QVERIFY(output.contains("debug  45 T::T static constructor"));
     //  we can't be sure whether the QT_MESSAGE_PATTERN is already destructed
     QVERIFY(output.contains("static destructor"));
-    QVERIFY(output.contains("debug tst_qlogging 54 main qDebug"));
-    QVERIFY(output.contains("warning tst_qlogging 55 main qWarning"));
-    QVERIFY(output.contains("critical tst_qlogging 56 main qCritical"));
+    QVERIFY(output.contains("debug tst_qlogging 56 main qDebug"));
+    QVERIFY(output.contains("warning tst_qlogging 57 main qWarning"));
+    QVERIFY(output.contains("critical tst_qlogging 58 main qCritical"));
+    QVERIFY(output.contains("debug tst_qlogging 62 main qDebug2"));
 
     environment = QProcess::systemEnvironment();
     environment.prepend("QT_MESSAGE_PATTERN=\"PREFIX: %{unknown} %{message}\"");
@@ -668,6 +672,32 @@ void tst_qmessagehandler::qMessagePattern()
 
     QVERIFY(output.contains("QT_MESSAGE_PATTERN: Unknown placeholder %{unknown}"));
     QVERIFY(output.contains("PREFIX:  qDebug"));
+
+    //
+    // test qSetMessagePattern
+    //
+    QMutableListIterator<QString> iter(environment);
+    while (iter.hasNext()) {
+        if (iter.next().startsWith("QT_MESSAGE_PATTERN"))
+            iter.remove();
+    }
+    process.setEnvironment(environment);
+
+    process.start(appExe);
+    QVERIFY2(process.waitForStarted(), qPrintable(
+        QString::fromLatin1("Could not start %1: %2").arg(appExe, process.errorString())));
+    process.waitForFinished();
+
+    output = process.readAllStandardError();
+    //qDebug() << output;
+    QByteArray expected = "static constructor\n"
+            "[debug] qDebug\n"
+            "[warning] qWarning\n"
+            "[critical] qCritical\n";
+#ifdef Q_OS_WIN
+    output.replace("\r\n", "\n");
+#endif
+    QCOMPARE(QString::fromLatin1(output), QString::fromLatin1(expected));
 }
 
 QTEST_MAIN(tst_qmessagehandler)