Cache the local Entities file to avoid reading 2 or 3 times

libraries/octree/src/OctreeDataUtils.cpp

@@ -18,30 +18,32 @@
 #include <QJsonDocument>
 #include <QFile>
 
-// Reads octree file and parses it into a QJsonDocument. Handles both gzipped and non-gzipped files.
-// Returns true if the file was successfully opened and parsed, otherwise false.
-// Example failures: file does not exist, gzipped file cannot be unzipped, invalid JSON.
-bool readOctreeFile(QString path, QJsonDocument* doc) {
-    QFile file(path);
-    if (!file.open(QIODevice::ReadOnly)) {
-        qCritical() << "Cannot open json file for reading: " << path;
-        return false;
-    }
+namespace {
+    // Reads octree file and parses it into a QJsonDocument. Handles both gzipped and non-gzipped files.
+    // Returns true if the file was successfully opened and parsed, otherwise false.
+    // Example failures: file does not exist, gzipped file cannot be unzipped, invalid JSON.
+    bool readOctreeFile(QString path, QJsonDocument* doc) {
+        QFile file(path);
+        if (!file.open(QIODevice::ReadOnly)) {
+            qCritical() << "Cannot open json file for reading: " << path;
+            return false;
+        }
 
-    QByteArray data = file.readAll();
-    QByteArray jsonData;
+        QByteArray data = file.readAll();
+        QByteArray jsonData;
 
-    if (!gunzip(data, jsonData)) {
-        jsonData = data;
-    }
+        if (!gunzip(data, jsonData)) {
+            jsonData = data;
+        }
 
-    QJsonParseError parserError;
-    *doc = QJsonDocument::fromJson(jsonData, &parserError);
-    if (parserError.error != QJsonParseError::NoError) {
-        qWarning() << "Error reading JSON file" << path << "-" << parserError.errorString();
+        QJsonParseError parserError;
+        *doc = QJsonDocument::fromJson(jsonData, &parserError);
+        if (parserError.error != QJsonParseError::NoError) {
+            qWarning() << "Error reading JSON file" << path << "-" << parserError.errorString();
+        }
+        return !doc->isNull();
     }
-    return !doc->isNull();
-}
+}  // Anon namespace.
 
 bool OctreeUtils::RawOctreeData::readOctreeDataInfoFromJSON(QJsonObject root) {
     if (root.contains("Id") && root.contains("DataVersion") && root.contains("Version")) {

libraries/octree/src/OctreeDataUtils.h

@@ -46,6 +46,7 @@ public:
 };
 
 class RawEntityData : public RawOctreeData {
+public:
     PacketType dataPacketType() const override;
     void readSubclassData(const QJsonObject& root) override;
     void writeSubclassData(QJsonObject& root) const override;

libraries/octree/src/OctreePersistThread.cpp

@@ -31,6 +31,7 @@
 #include <NumericalConstants.h>
 #include <PerfStat.h>
 #include <PathUtils.h>
+#include <Gzip.h>
 
 #include "OctreeLogging.h"
 #include "OctreeUtils.h"
@@ -72,14 +73,27 @@ void OctreePersistThread::start() {
 
     OctreeUtils::RawOctreeData data;
     qCDebug(octree) << "Reading octree data from" << _filename;
-    if (data.readOctreeDataInfoFromFile(_filename)) {
-        qCDebug(octree) << "Current octree data: ID(" << data.id << ") DataVersion(" << data.version << ")";
-        packet->writePrimitive(true);
-        auto id = data.id.toRfc4122();
-        packet->write(id);
-        packet->writePrimitive(data.version);
+    QFile file(_filename);
+    if (file.open(QIODevice::ReadOnly)) {
+        QByteArray jsonData(file.readAll());
+        file.close();
+        if (!gunzip(jsonData, _cachedJSONData)) {
+            _cachedJSONData = jsonData;
+        }
+
+        if (data.readOctreeDataInfoFromData(_cachedJSONData)) {
+            qCDebug(octree) << "Current octree data: ID(" << data.id << ") DataVersion(" << data.version << ")";
+            packet->writePrimitive(true);
+            auto id = data.id.toRfc4122();
+            packet->write(id);
+            packet->writePrimitive(data.version);
+        } else {
+            _cachedJSONData.clear();
+            qCWarning(octree) << "No octree data found";
+            packet->writePrimitive(false);
+        }
     } else {
-        qCWarning(octree) << "No octree data found";
+        qCWarning(octree) << "Couldn't access file" << _filename << file.errorString();
         packet->writePrimitive(false);
     }
 
@@ -99,6 +113,7 @@ void OctreePersistThread::handleOctreeDataFileReply(QSharedPointer<ReceivedMessa
     OctreeUtils::RawOctreeData data;
     bool hasValidOctreeData { false };
     if (includesNewData) {
+        _cachedJSONData.clear();
         replacementData = message->readAll();
         replaceData(replacementData);
         hasValidOctreeData = data.readOctreeDataInfoFromFile(_filename);
@@ -108,7 +123,7 @@ void OctreePersistThread::handleOctreeDataFileReply(QSharedPointer<ReceivedMessa
         
         OctreeUtils::RawEntityData data;
         qCDebug(octree) << "Reading octree data from" << _filename;
-        if (data.readOctreeDataInfoFromFile(_filename)) {
+        if (data.readOctreeDataInfoFromData(_cachedJSONData)) {
             hasValidOctreeData = true;
             if (data.id.isNull()) {
                 qCDebug(octree) << "Current octree data has a null id, updating";
@@ -139,10 +154,16 @@ void OctreePersistThread::handleOctreeDataFileReply(QSharedPointer<ReceivedMessa
     _tree->withWriteLock([&] {
         PerformanceWarning warn(true, "Loading Octree File", true);
 
-        persistentFileRead = _tree->readFromFile(_filename.toLocal8Bit().constData());
+        if (_cachedJSONData.isEmpty()) {
+            persistentFileRead = _tree->readFromFile(_filename.toLocal8Bit().constData());
+        } else {
+            QDataStream jsonStream(_cachedJSONData);
+            persistentFileRead = _tree->readFromStream(-1, QDataStream(_cachedJSONData));
+        }
         _tree->pruneTree();
     });
 
+    _cachedJSONData.clear();
     quint64 loadDone = usecTimestampNow();
     _loadTimeUSecs = loadDone - loadStarted;
 

libraries/octree/src/OctreePersistThread.h

@@ -78,6 +78,7 @@ private:
     quint64 _lastTimeDebug;
 
     QString _persistAsFileType;
+    QByteArray _cachedJSONData;
 };
 
 #endif // hifi_OctreePersistThread_h