[logging-log4cxx] branch next_stable updated: LOGCXX-572 Add support to Qt to reload config file when it changes (#174)

[rm...@apache.org]

This is an automated email from the ASF dual-hosted git repository.

rmiddleton pushed a commit to branch next_stable
in repository https://gitbox.apache.org/repos/asf/logging-log4cxx.git


The following commit(s) were added to refs/heads/next_stable by this push:
     new 0f79f627 LOGCXX-572 Add support to Qt to reload config file when it changes (#174)
0f79f627 is described below

commit 0f79f6275adea642967adc2e24b1af1489df32ac
Author: Robert Middleton <rm...@users.noreply.github.com>
AuthorDate: Thu Dec 29 08:59:45 2022 -0500

    LOGCXX-572 Add support to Qt to reload config file when it changes (#174)
---
 src/main/cpp-qt/CMakeLists.txt              |   1 +
 src/main/cpp-qt/configuration.cpp           | 122 ++++++++++++++++++++++++++++
 src/main/include/log4cxx-qt/configuration.h |  49 +++++++++++
 3 files changed, 172 insertions(+)

diff --git a/src/main/cpp-qt/CMakeLists.txt b/src/main/cpp-qt/CMakeLists.txt
index 48508492..5b9684b0 100644
--- a/src/main/cpp-qt/CMakeLists.txt
+++ b/src/main/cpp-qt/CMakeLists.txt
@@ -33,6 +33,7 @@ if(LOG4CXX_QT_SUPPORT)
     target_sources(log4cxx-qt
       PRIVATE
       messagehandler.cpp
+	  configuration.cpp
     )
     set_target_properties(log4cxx-qt PROPERTIES
       VERSION ${LIBLOG4CXX_LIB_VERSION}
diff --git a/src/main/cpp-qt/configuration.cpp b/src/main/cpp-qt/configuration.cpp
new file mode 100644
index 00000000..516acef4
--- /dev/null
+++ b/src/main/cpp-qt/configuration.cpp
@@ -0,0 +1,122 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+#include <log4cxx-qt/configuration.h>
+#include <log4cxx/helpers/loglog.h>
+#include <log4cxx/xml/domconfigurator.h>
+#include <log4cxx/propertyconfigurator.h>
+
+#include <QFileSystemWatcher>
+#include <QDir>
+#include <QFile>
+#include <memory>
+#include <QDebug>
+
+using log4cxx::qt::Configuration;
+using log4cxx::helpers::LogLog;
+
+static std::unique_ptr<QFileSystemWatcher> watcher;
+static QString configFilename;
+
+static void loadXMLFile(const QString& path){
+	QFileInfo fi(configFilename);
+	if(!fi.exists()){
+		return;
+	}
+	log4cxx::xml::DOMConfigurator::configure(path.toStdString());
+}
+
+static void loadPropertiesFile(const QString& path){
+	QFileInfo fi(configFilename);
+	if(!fi.exists()){
+		return;
+	}
+	log4cxx::PropertyConfigurator::configure(path.toStdString());
+}
+
+static void dirChanged(const QString&){
+	QFileInfo fi(configFilename);
+	if(fi.exists()){
+		// From the Qt docs:
+		// Note that QFileSystemWatcher stops monitoring files once they have been renamed
+		// or removed from disk, and directories once they have been removed from disk.
+		//
+		// Some text editing programs will replace the file with a new one, which deletes
+		// the old file(thus causing Qt to remove the watch), so we need to add in the
+		// file whenever the directory changes.
+		// See also: https://stackoverflow.com/questions/18300376/qt-qfilesystemwatcher-signal-filechanged-gets-emited-only-once
+		watcher->addPath(configFilename);
+	}
+}
+
+Configuration::Configuration(){}
+
+log4cxx::spi::ConfigurationStatus Configuration::tryLoadFile(const QString& filename){
+	log4cxx::spi::ConfigurationStatus stat =log4cxx::spi::ConfigurationStatus::NotConfigured;
+	bool isXML = false;
+
+	if(filename.endsWith(".xml")){
+		stat = log4cxx::xml::DOMConfigurator::configure(filename.toStdString());
+		isXML = true;
+	}else if(filename.endsWith(".properties")){
+		stat = log4cxx::PropertyConfigurator::configure(filename.toStdString());
+	}
+
+	if( stat == log4cxx::spi::ConfigurationStatus::Configured ){
+		watcher = std::make_unique<QFileSystemWatcher>();
+		configFilename = filename;
+		QFileInfo fi(filename);
+		watcher->addPath(fi.dir().absolutePath());
+		watcher->addPath(filename);
+
+		QObject::connect(watcher.get(), &QFileSystemWatcher::directoryChanged,
+						 &dirChanged);
+		if(isXML){
+			QObject::connect(watcher.get(), &QFileSystemWatcher::fileChanged,
+							 &loadXMLFile);
+		}else{
+			QObject::connect(watcher.get(), &QFileSystemWatcher::fileChanged,
+							 &loadPropertiesFile);
+		}
+	}
+
+	return stat;
+}
+
+std::tuple<log4cxx::spi::ConfigurationStatus,QString>
+Configuration::configureFromFileAndWatch(const QVector<QString>& directories,
+										 const QVector<QString>& filenames){
+	for( QString dir : directories ){
+		for( QString fname : filenames ){
+			QString canidate_str = dir + "/" + fname;
+			QFile candidate(canidate_str);
+
+			QString debugMsg = LOG4CXX_STR("Checking file ");
+			debugMsg.append(canidate_str);
+			LogLog::debug(debugMsg.toStdString());
+			if (candidate.exists())
+			{
+				log4cxx::spi::ConfigurationStatus configStatus = tryLoadFile(canidate_str);
+				if( configStatus == log4cxx::spi::ConfigurationStatus::Configured ){
+					return {configStatus, canidate_str};
+				}
+				LogLog::debug("Unable to load file: trying next");
+			}
+		}
+	}
+
+	return {log4cxx::spi::ConfigurationStatus::NotConfigured, QString()};
+}
diff --git a/src/main/include/log4cxx-qt/configuration.h b/src/main/include/log4cxx-qt/configuration.h
new file mode 100644
index 00000000..ec16b9db
--- /dev/null
+++ b/src/main/include/log4cxx-qt/configuration.h
@@ -0,0 +1,49 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+#ifndef LOG4CXX_QT_CONFIGURATION_H
+#define LOG4CXX_QT_CONFIGURATION_H
+
+#include <QString>
+#include <QVector>
+#include <log4cxx/log4cxx.h>
+#include <log4cxx/defaultconfigurator.h>
+
+namespace log4cxx {
+namespace qt {
+
+class LOG4CXX_EXPORT Configuration {
+private:
+	Configuration();
+
+	static log4cxx::spi::ConfigurationStatus tryLoadFile(const QString& filename);
+
+public:
+	/**
+	 * Configure Log4cxx and watch the file for changes.  See also DefaultConfigurator::configureFromFile.
+	 *
+	 * @param directories
+	 * @param filenames
+	 * @return
+	 */
+	static std::tuple<log4cxx::spi::ConfigurationStatus,QString> configureFromFileAndWatch(const QVector<QString>& directories,
+																						   const QVector<QString>& filenames);
+};
+
+} /* namespace qt */
+} /* namespace log4cxx */
+
+#endif /* LOG4CXX_QT_CONFIGURATION_H */