From efe443e2ff5b930b10bc8c075152af8e7b286b96 Mon Sep 17 00:00:00 2001
From: Andrzej Kapolka <drzej.k@gmail.com>
Date: Wed, 9 Jul 2014 14:01:46 -0700
Subject: [PATCH] Very basic metavoxel save/load.

---
 .../src/metavoxels/MetavoxelServer.cpp        | 59 +++++++++++++++++++
 .../src/metavoxels/MetavoxelServer.h          | 23 ++++++++
 libraries/metavoxels/src/Bitstream.cpp        |  6 ++
 libraries/metavoxels/src/Bitstream.h          |  5 ++
 4 files changed, 93 insertions(+)

diff --git a/assignment-client/src/metavoxels/MetavoxelServer.cpp b/assignment-client/src/metavoxels/MetavoxelServer.cpp
index 14765e2ddc..928a693527 100644
--- a/assignment-client/src/metavoxels/MetavoxelServer.cpp
+++ b/assignment-client/src/metavoxels/MetavoxelServer.cpp
@@ -10,6 +10,9 @@
 //
 
 #include <QDateTime>
+#include <QFile>
+#include <QSaveFile>
+#include <QThread>
 
 #include <PacketHeaders.h>
 
@@ -44,6 +47,18 @@ void MetavoxelServer::run() {
     
     _lastSend = QDateTime::currentMSecsSinceEpoch();
     _sendTimer.start(SEND_INTERVAL);
+    
+    // initialize Bitstream before using it in multiple threads
+    Bitstream::preThreadingInit();
+    
+    // create the persister and start the it in its own thread
+    _persister = new MetavoxelPersister(this);
+    QThread* persistenceThread = new QThread(this);
+    _persister->moveToThread(persistenceThread);
+    persistenceThread->start();
+    
+    // queue up the load
+    QMetaObject::invokeMethod(_persister, "load");
 }
 
 void MetavoxelServer::readPendingDatagrams() {
@@ -67,6 +82,12 @@ void MetavoxelServer::readPendingDatagrams() {
     }
 }
 
+void MetavoxelServer::aboutToFinish() {
+    QMetaObject::invokeMethod(_persister, "save", Q_ARG(const MetavoxelData&, _data));
+    _persister->thread()->quit();
+    _persister->thread()->wait();
+}
+
 void MetavoxelServer::maybeAttachSession(const SharedNodePointer& node) {
     if (node->getType() == NodeType::Agent) {
         QMutexLocker locker(&node->getMutex());
@@ -193,3 +214,41 @@ void MetavoxelSession::sendPacketGroup(int alreadySent) {
         _sequencer.endPacket();
     }
 }
+
+MetavoxelPersister::MetavoxelPersister(MetavoxelServer* server) :
+    _server(server) {
+}
+
+const char* SAVE_FILE = "metavoxels.dat";
+
+void MetavoxelPersister::load() {
+    QFile file(SAVE_FILE);
+    if (!file.exists()) {
+        return;
+    }
+    QDebug debug = qDebug() << "Reading from" << SAVE_FILE << "...";
+    file.open(QIODevice::ReadOnly);
+    QDataStream inStream(&file);
+    Bitstream in(inStream);
+    MetavoxelData data;
+    try {
+        in >> data;
+    } catch (const BitstreamException& e) {
+        debug << "failed, " << e.getDescription();
+        return;
+    }
+    QMetaObject::invokeMethod(_server, "setData", Q_ARG(const MetavoxelData&, data));
+    debug << "done.";
+}
+
+void MetavoxelPersister::save(const MetavoxelData& data) {
+    QDebug debug = qDebug() << "Writing to" << SAVE_FILE << "...";
+    QSaveFile file(SAVE_FILE);
+    file.open(QIODevice::WriteOnly);
+    QDataStream outStream(&file);
+    Bitstream out(outStream);
+    out << data;
+    out.flush();
+    file.commit();
+    debug << "done.";
+}
diff --git a/assignment-client/src/metavoxels/MetavoxelServer.h b/assignment-client/src/metavoxels/MetavoxelServer.h
index 6df769227c..9ed765f65f 100644
--- a/assignment-client/src/metavoxels/MetavoxelServer.h
+++ b/assignment-client/src/metavoxels/MetavoxelServer.h
@@ -20,6 +20,7 @@
 #include <Endpoint.h>
 
 class MetavoxelEditMessage;
+class MetavoxelPersister;
 class MetavoxelSession;
 
 /// Maintains a shared metavoxel system, accepting change requests and broadcasting updates.
@@ -33,11 +34,15 @@ public:
     void applyEdit(const MetavoxelEditMessage& edit);
 
     const MetavoxelData& getData() const { return _data; }
+    
+    Q_INVOKABLE void setData(const MetavoxelData& data) { _data = data; }
 
     virtual void run();
     
     virtual void readPendingDatagrams();
     
+    virtual void aboutToFinish();
+    
 private slots:
 
     void maybeAttachSession(const SharedNodePointer& node);
@@ -45,6 +50,8 @@ private slots:
     
 private:
     
+    MetavoxelPersister* _persister;
+    
     QTimer _sendTimer;
     qint64 _lastSend;
     
@@ -88,4 +95,20 @@ private:
     int _reliableDeltaID;
 };
 
+/// Handles persistence in a separate thread.
+class MetavoxelPersister : public QObject {
+    Q_OBJECT
+
+public:
+    
+    MetavoxelPersister(MetavoxelServer* server);
+
+    Q_INVOKABLE void load();
+    Q_INVOKABLE void save(const MetavoxelData& data);
+
+private:
+    
+    MetavoxelServer* _server;
+};
+
 #endif // hifi_MetavoxelServer_h
diff --git a/libraries/metavoxels/src/Bitstream.cpp b/libraries/metavoxels/src/Bitstream.cpp
index bc662aa890..0d4f8a52b4 100644
--- a/libraries/metavoxels/src/Bitstream.cpp
+++ b/libraries/metavoxels/src/Bitstream.cpp
@@ -87,6 +87,12 @@ IDStreamer& IDStreamer::operator>>(int& value) {
     return *this;
 }
 
+void Bitstream::preThreadingInit() {
+    getObjectStreamers();
+    getEnumStreamers();
+    getEnumStreamersByName();    
+}
+
 int Bitstream::registerMetaObject(const char* className, const QMetaObject* metaObject) {
     getMetaObjects().insert(className, metaObject);
     
diff --git a/libraries/metavoxels/src/Bitstream.h b/libraries/metavoxels/src/Bitstream.h
index 70fde94b79..dacfeb2ee9 100644
--- a/libraries/metavoxels/src/Bitstream.h
+++ b/libraries/metavoxels/src/Bitstream.h
@@ -290,6 +290,11 @@ public:
         QHash<int, SharedObjectPointer> sharedObjectValues;
     };
 
+    /// Performs all of the various lazily initializations (of object streamers, etc.)  If multiple threads need to use
+    /// Bitstream instances, call this beforehand to prevent errors from occurring when multiple threads attempt lazy
+    /// initialization simultaneously.
+    static void preThreadingInit();
+
     /// Registers a metaobject under its name so that instances of it can be streamed.  Consider using the REGISTER_META_OBJECT
     /// at the top level of the source file associated with the class rather than calling this function directly.
     /// \return zero; the function only returns a value so that it can be used in static initialization