Allow configuration of logging rules from file system

Allow configuration of logging rules from outside of the application,
either through a configuration file (.config/QtProject/qtlogging.ini),
or through a file specified by a QT_LOGGING_CONF environment
variable.

The logging rules from the different sources are concatenated: First
the rules from QtProject/qtlogging.ini are applied, then
QLoggingCategory::setLoggingRules(), finally from the environment.
This allows an application to overwrite/augment the system wide rules,
and in turn that can be tailored for a specific run by setting a
configuration in the environment variable.

[ChangeLog][QtCore][Logging] The logging framework can now be configured
with an .ini file.

Change-Id: I442efde1b7e0a2ebe135c6f6e0a4b656483fe4b1
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

3 files changed, 189 insertions, 0 deletions

diff --git a/tests/auto/corelib/io/qloggingregistry/qloggingregistry.pro b/tests/auto/corelib/io/qloggingregistry/qloggingregistry.pro
new file mode 100644
index 0000000000..c6c4caace3
--- /dev/null
+++ b/tests/auto/corelib/io/qloggingregistry/qloggingregistry.pro
@@ -0,0 +1,8 @@
+TEMPLATE = app
+TARGET = tst_qloggingregistry
+
+CONFIG += testcase
+QT = core core-private testlib
+
+SOURCES += tst_qloggingregistry.cpp
+OTHER_FILES += qtlogging.ini
diff --git a/tests/auto/corelib/io/qloggingregistry/qtlogging.ini b/tests/auto/corelib/io/qloggingregistry/qtlogging.ini
new file mode 100644
index 0000000000..63b384e36a
--- /dev/null
+++ b/tests/auto/corelib/io/qloggingregistry/qtlogging.ini
@@ -0,0 +1,2 @@
+[rules]
+*=true
diff --git a/tests/auto/corelib/io/qloggingregistry/tst_qloggingregistry.cpp b/tests/auto/corelib/io/qloggingregistry/tst_qloggingregistry.cpp
new file mode 100644
index 0000000000..b538525161
--- /dev/null
+++ b/tests/auto/corelib/io/qloggingregistry/tst_qloggingregistry.cpp
@@ -0,0 +1,179 @@
+/****************************************************************************
+**
+** Copyright (C) 2014 Digia Plc and/or its subsidiary(-ies).
+** Contact: http://www.qt-project.org/legal
+**
+** This file is part of the test suite of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and Digia.  For licensing terms and
+** conditions see http://qt.digia.com/licensing.  For further information
+** use the contact form at http://qt.digia.com/contact-us.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 2.1 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPL included in the
+** packaging of this file.  Please review the following information to
+** ensure the GNU Lesser General Public License version 2.1 requirements
+** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
+**
+** In addition, as a special exception, Digia gives you certain additional
+** rights.  These rights are described in the Digia Qt LGPL Exception
+** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 3.0 as published by the Free Software
+** Foundation and appearing in the file LICENSE.GPL included in the
+** packaging of this file.  Please review the following information to
+** ensure the GNU General Public License version 3.0 requirements will be
+** met: http://www.gnu.org/copyleft/gpl.html.
+**
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#include <QtTest>
+#include <QLoggingCategory>
+
+#include <QtCore/private/qloggingregistry_p.h>
+
+QT_USE_NAMESPACE
+
+class tst_QLoggingRegistry : public QObject
+{
+    Q_OBJECT
+
+private slots:
+
+    void initTestCase()
+    {
+        // ensure a clean environment
+        QStandardPaths::setTestModeEnabled(true);
+        qunsetenv("QT_LOGGING_CONF");
+    }
+
+    void QLoggingSettingsParser_iniStyle()
+    {
+        //
+        // Logging configuration can be described
+        // in an .ini file. [rules] is the
+        // default category, and optional ...
+        //
+        QLoggingSettingsParser parser;
+        parser.setContent("[rules]\n"
+                          "default=false\n"
+                          "default=true");
+        QCOMPARE(parser.rules().size(), 2);
+
+        parser.setContent("[rules]\n"
+                          "default=false");
+        QCOMPARE(parser.rules().size(), 1);
+
+        parser.setContent("[OtherSection]\n"
+                          "default=false");
+        QCOMPARE(parser.rules().size(), 0);
+    }
+
+    void QLoggingRegistry_environment()
+    {
+        //
+        // Check whether QT_LOGGING_CONF is picked up from environment
+        //
+
+        qputenv("QT_LOGGING_CONF", QFINDTESTDATA("qtlogging.ini").toLocal8Bit());
+
+        QLoggingRegistry registry;
+        registry.init();
+
+        QCOMPARE(registry.apiRules.size(), 0);
+        QCOMPARE(registry.configRules.size(), 0);
+        QCOMPARE(registry.envRules.size(), 1);
+
+        QCOMPARE(registry.rules.size(), 1);
+    }
+
+    void QLoggingRegistry_config()
+    {
+        //
+        // Check whether QtProject/qtlogging.ini is loaded automatically
+        //
+
+        // first try to create a test file..
+        QString path = QStandardPaths::writableLocation(QStandardPaths::GenericConfigLocation);
+        QVERIFY(!path.isEmpty());
+        QDir dir(path + "/QtProject");
+        if (!dir.exists())
+            QVERIFY(dir.mkpath(path + "/QtProject"));
+
+        QFile file(dir.absoluteFilePath("qtlogging.ini"));
+        QVERIFY(file.open(QFile::WriteOnly | QFile::Text));
+        QTextStream out(&file);
+        out << "[rules]\n";
+        out << "Digia.*=false\n";
+        file.close();
+
+        QLoggingRegistry registry;
+        registry.init();
+        QCOMPARE(registry.configRules.size(), 1);
+
+        // remove file again
+        QVERIFY(file.remove());
+    }
+
+    void QLoggingRegistry_rulePriorities()
+    {
+        //
+        // Rules can stem from 3 sources:
+        //   via QLoggingCategory::setFilterRules (API)
+        //   via qtlogging.ini file in settings (Config)
+        //   via QT_LOGGING_CONF environment variable (Env)
+        //
+        // Rules set by environment should get higher precedence than qtlogging.conf,
+        // than QLoggingCategory::setFilterRules
+        //
+
+        QLoggingCategory cat("Digia.Berlin");
+        QLoggingRegistry *registry = QLoggingRegistry::instance();
+
+        // empty all rules , check default
+        registry->rules.clear();
+        registry->apiRules.clear();
+        registry->configRules.clear();
+        registry->envRules.clear();
+        registry->updateRules();
+
+        QVERIFY(cat.isWarningEnabled());
+
+        // set Config rule
+        QLoggingSettingsParser parser;
+        parser.setContent("[rules]\nDigia.*=false");
+        registry->configRules=parser.rules();
+        registry->updateRules();
+
+        QVERIFY(!cat.isWarningEnabled());
+
+        // set API rule, should overwrite API one
+        QLoggingCategory::setFilterRules("Digia.*=true");
+
+        QVERIFY(cat.isWarningEnabled());
+
+        // set Env rule, should overwrite Config one
+        parser.setContent("Digia.*=false");
+        registry->envRules=parser.rules();
+        registry->updateRules();
+
+        QVERIFY(!cat.isWarningEnabled());
+    }
+
+};
+
+QTEST_MAIN(tst_QLoggingRegistry)
+
+#include "tst_qloggingregistry.moc"