From 08d1364f81616093bec3700dd26b98aec008fadf Mon Sep 17 00:00:00 2001
From: Brad Davis <bdavis@saintandreas.org>
Date: Wed, 8 Jul 2015 22:35:23 -0700
Subject: [PATCH] Move file log persistence to a separate thread

---
 interface/src/AbstractLoggerInterface.h   |  4 +-
 interface/src/FileLogger.cpp              | 42 +++++++++----
 interface/src/FileLogger.h                | 10 ++--
 libraries/shared/src/GenericQueueThread.h | 72 +++++++++++++++++++++++
 libraries/shared/src/GenericThread.cpp    |  3 +-
 libraries/shared/src/GenericThread.h      |  2 +-
 6 files changed, 115 insertions(+), 18 deletions(-)
 create mode 100644 libraries/shared/src/GenericQueueThread.h

diff --git a/interface/src/AbstractLoggerInterface.h b/interface/src/AbstractLoggerInterface.h
index fe45346e4c..3823060b13 100644
--- a/interface/src/AbstractLoggerInterface.h
+++ b/interface/src/AbstractLoggerInterface.h
@@ -24,7 +24,7 @@ public:
     inline bool extraDebugging() { return _extraDebugging; }
     inline void setExtraDebugging(bool debugging) { _extraDebugging = debugging; }
 
-    virtual void addMessage(QString) = 0;
+    virtual void addMessage(const QString&) = 0;
     virtual QString getLogData() = 0;
     virtual void locateLog() = 0;
 
@@ -32,7 +32,7 @@ signals:
     void logReceived(QString message);
 
 private:
-    bool _extraDebugging;
+    bool _extraDebugging{ false };
 };
 
 #endif // hifi_AbstractLoggerInterface_h
diff --git a/interface/src/FileLogger.cpp b/interface/src/FileLogger.cpp
index 4808842036..bcae96b2ea 100644
--- a/interface/src/FileLogger.cpp
+++ b/interface/src/FileLogger.cpp
@@ -21,11 +21,35 @@ const QString FILENAME_FORMAT = "hifi-log_%1_%2.txt";
 const QString DATETIME_FORMAT = "yyyy-MM-dd_hh.mm.ss";
 const QString LOGS_DIRECTORY = "Logs";
 
+class FilePersistThread : public GenericQueueThread < QString > {    
+public:
+    FilePersistThread(FileLogger& logger) : _logger(logger) {
+        setObjectName("LogFileWriter");
+    }
+
+protected:
+    virtual bool processQueueItems(const Queue& messages) {
+        QFile file(_logger._fileName);
+        if (file.open(QIODevice::WriteOnly | QIODevice::Append | QIODevice::Text)) {
+            QTextStream out(&file);
+            foreach(const QString& message, messages) {
+                out << message;
+            }
+        }
+        return true;
+    }
+private:
+    FileLogger& _logger;
+};
+
+static FilePersistThread* _persistThreadInstance;
+
 FileLogger::FileLogger(QObject* parent) :
     AbstractLoggerInterface(parent),
     _logData("")
 {
-    setExtraDebugging(false);
+    _persistThreadInstance = new FilePersistThread(*this);
+    _persistThreadInstance->initialize(true);
 
     _fileName = FileUtils::standardPath(LOGS_DIRECTORY);
     QHostAddress clientAddress = getLocalAddress();
@@ -33,16 +57,14 @@ FileLogger::FileLogger(QObject* parent) :
     _fileName.append(QString(FILENAME_FORMAT).arg(clientAddress.toString(), now.toString(DATETIME_FORMAT)));
 }
 
-void FileLogger::addMessage(QString message) {
-    QMutexLocker locker(&_mutex);
-    emit logReceived(message);
-    _logData += message;
+FileLogger::~FileLogger() {
+    _persistThreadInstance->terminate();
+}
 
-    QFile file(_fileName);
-    if (file.open(QIODevice::WriteOnly | QIODevice::Append | QIODevice::Text)) {
-        QTextStream out(&file);
-        out <<  message;
-    }
+void FileLogger::addMessage(const QString& message) {
+    _persistThreadInstance->queueItem(message);
+    emit logReceived(message);
+    //_logData += message;
 }
 
 void FileLogger::locateLog() {
diff --git a/interface/src/FileLogger.h b/interface/src/FileLogger.h
index 3dbbfd26cd..72bffa6445 100644
--- a/interface/src/FileLogger.h
+++ b/interface/src/FileLogger.h
@@ -13,23 +13,25 @@
 #define hifi_FileLogger_h
 
 #include "AbstractLoggerInterface.h"
-#include <QMutex>
+#include <GenericQueueThread.h>
 
 class FileLogger : public AbstractLoggerInterface {
     Q_OBJECT
 
 public:
     FileLogger(QObject* parent = NULL);
+    virtual ~FileLogger();
 
-    virtual void addMessage(QString);
+    virtual void addMessage(const QString&);
     virtual QString getLogData() { return _logData; }
     virtual void locateLog();
 
 private:
     QString _logData;
     QString _fileName;
-    QMutex _mutex;
-
+    friend class FilePersistThread;
 };
 
+
+
 #endif // hifi_FileLogger_h
diff --git a/libraries/shared/src/GenericQueueThread.h b/libraries/shared/src/GenericQueueThread.h
new file mode 100644
index 0000000000..2a48ff7418
--- /dev/null
+++ b/libraries/shared/src/GenericQueueThread.h
@@ -0,0 +1,72 @@
+//
+//  Created by Bradley Austin Davis 2015/07/08.
+//  Copyright 2015 High Fidelity, Inc.
+//
+//  Distributed under the Apache License, Version 2.0.
+//  See the accompanying file LICENSE or http://www.apache.org/licenses/LICENSE-2.0.html
+//
+
+#pragma once
+#ifndef hifi_GenericQueueThread_h
+#define hifi_GenericQueueThread_h
+
+#include <stdint.h>
+
+#include <QQueue>
+#include <QMutex>
+#include <QWaitCondition>
+
+#include "GenericThread.h"
+#include "NumericalConstants.h"
+
+template <typename T>
+class GenericQueueThread : public GenericThread {
+public:
+    using Queue = QQueue<T>;
+    GenericQueueThread(QObject* parent = nullptr) 
+        : GenericThread(parent) {}
+
+    virtual ~GenericQueueThread() {}
+
+    void queueItem(const T& t) {
+        lock();
+        queueItemInternal(t);
+        unlock();
+        _hasItems.wakeAll();
+    }
+
+protected:
+    virtual void queueItemInternal(const T& t) {
+        _items.push_back(t);
+    }
+
+    virtual uint32_t getMaxWait() {
+        return MSECS_PER_SECOND;
+    }
+
+    virtual bool process() {
+        if (!_items.size()) {
+            _hasItemsMutex.lock();
+            _hasItems.wait(&_hasItemsMutex, getMaxWait());
+            _hasItemsMutex.unlock();
+        }
+
+        if (!_items.size()) {
+            return isStillRunning();
+        }
+
+        Queue processItems;
+        lock();
+        processItems.swap(_items);
+        unlock();
+        return processQueueItems(processItems);
+    }
+
+    virtual bool processQueueItems(const Queue& items) = 0;
+
+    Queue _items;
+    QWaitCondition _hasItems;
+    QMutex _hasItemsMutex;
+};
+
+#endif // hifi_GenericQueueThread_h
diff --git a/libraries/shared/src/GenericThread.cpp b/libraries/shared/src/GenericThread.cpp
index 3068ca2ab6..a7e0f3456b 100644
--- a/libraries/shared/src/GenericThread.cpp
+++ b/libraries/shared/src/GenericThread.cpp
@@ -14,7 +14,8 @@
 #include "GenericThread.h"
 
 
-GenericThread::GenericThread() :
+GenericThread::GenericThread(QObject* parent) : 
+    QObject(parent),
     _stopThread(false),
     _isThreaded(false) // assume non-threaded, must call initialize()
 {
diff --git a/libraries/shared/src/GenericThread.h b/libraries/shared/src/GenericThread.h
index b2c0eb13db..6fe6b6ccb4 100644
--- a/libraries/shared/src/GenericThread.h
+++ b/libraries/shared/src/GenericThread.h
@@ -23,7 +23,7 @@
 class GenericThread : public QObject {
     Q_OBJECT
 public:
-    GenericThread();
+    GenericThread(QObject* parent = nullptr);
     virtual ~GenericThread();
 
     /// Call to start the thread.