Fix cache mixing with high-dpi and low-dpi osm providers

This cache fixes the cache mixing problem that has been introduced
with the osm high dpi tiles support.

high dpi providers fall back to low dpi ones and ultimately
to hardcoded providers (also low dpi), and can also be enabled/disabled
via plugin parameter, thus leaving the cache for a given map id
dirty for the next run.

With this patch high dpi tiles are named differently from low dpi ones.
If high-dpi providers are selected, but become not available, the
cache can also change the tileset to load at runtime

Change-Id: I229692da07c1fc61c58fb0b6fae6ec5af16e43a7
Reviewed-by: Paolo Angelelli <paolo.angelelli@qt.io>

1 files changed, 139 insertions, 3 deletions

diff --git a/src/plugins/geoservices/osm/qgeofiletilecacheosm.cpp b/src/plugins/geoservices/osm/qgeofiletilecacheosm.cpp
index a780faa9..a8429f3d 100644
--- a/src/plugins/geoservices/osm/qgeofiletilecacheosm.cpp
+++ b/src/plugins/geoservices/osm/qgeofiletilecacheosm.cpp
@@ -45,10 +45,16 @@
 
 QT_BEGIN_NAMESPACE
 
-QGeoFileTileCacheOsm::QGeoFileTileCacheOsm(const QString &offlineDirectory, const QString &directory, QObject *parent)
-    :QGeoFileTileCache(directory, parent), m_offlineDirectory(offlineDirectory),
-     m_requestCancel(0)
+QGeoFileTileCacheOsm::QGeoFileTileCacheOsm(const QVector<QGeoTileProviderOsm *> &providers, const QString &offlineDirectory, const QString &directory, QObject *parent)
+:   QGeoFileTileCache(directory, parent), m_offlineDirectory(offlineDirectory),
+     m_requestCancel(0), m_providers(providers)
 {
+    m_highDpi.resize(providers.size());
+    for (int i = 0; i < providers.size(); i++) {
+        m_highDpi[i] = providers[i]->isHighDpi();
+        connect(providers[i], &QGeoTileProviderOsm::resolutionFinished, this, &QGeoFileTileCacheOsm::onProviderResolutionFinished);
+        connect(providers[i], &QGeoTileProviderOsm::resolutionError, this, &QGeoFileTileCacheOsm::onProviderResolutionFinished);
+    }
 }
 
 QGeoFileTileCacheOsm::~QGeoFileTileCacheOsm()
@@ -67,6 +73,24 @@ QSharedPointer<QGeoTileTexture> QGeoFileTileCacheOsm::get(const QGeoTileSpec &sp
     return getFromDisk(spec);
 }
 
+void QGeoFileTileCacheOsm::onProviderResolutionFinished(const QGeoTileProviderOsm *provider)
+{
+    Q_UNUSED(provider)
+    for (int i = 0; i < m_providers.size(); i++) {
+        if (m_providers[i]->isHighDpi() != m_highDpi[i]) {
+            int mapId = m_providers[i]->mapType().mapId();
+            m_highDpi[i] = m_providers[i]->isHighDpi();
+
+            // reload cache for mapId i
+            dropTiles(mapId);
+            loadTiles(mapId);
+
+            // send signal to clear scene in all maps created through this provider that use the reloaded tiles
+            emit mapDataUpdated(mapId);
+        }
+    }
+}
+
 void QGeoFileTileCacheOsm::init()
 {
     QGeoFileTileCache::init();
@@ -99,6 +123,42 @@ QSharedPointer<QGeoTileTexture> QGeoFileTileCacheOsm::getFromOfflineStorage(cons
     return QSharedPointer<QGeoTileTexture>();
 }
 
+void QGeoFileTileCacheOsm::dropTiles(int mapId)
+{
+    QList<QGeoTileSpec> keys;
+    keys = textureCache_.keys();
+    for (const QGeoTileSpec &k : keys)
+        if (k.mapId() == mapId)
+            textureCache_.remove(k);
+
+    keys = memoryCache_.keys();
+    for (const QGeoTileSpec &k : keys)
+        if (k.mapId() == mapId)
+            memoryCache_.remove(k);
+
+    keys = diskCache_.keys();
+    for (const QGeoTileSpec &k : keys)
+        if (k.mapId() == mapId)
+            diskCache_.remove(k);
+}
+
+void QGeoFileTileCacheOsm::loadTiles(int mapId)
+{
+    QStringList formats;
+    formats << QLatin1String("*.*");
+
+    QDir dir(directory_);
+    QStringList files = dir.entryList(formats, QDir::Files);
+
+    for (int i = 0; i < files.size(); ++i) {
+        QGeoTileSpec spec = filenameToTileSpec(files.at(i));
+        if (spec.zoom() == -1 || spec.mapId() != mapId)
+            continue;
+        QString filename = dir.filePath(files.at(i));
+        addToDiskCache(spec, filename);
+    }
+}
+
 void QGeoFileTileCacheOsm::initOfflineRegistry()
 {
     // Dealing with duplicates: picking the newest
@@ -128,4 +188,80 @@ void QGeoFileTileCacheOsm::initOfflineRegistry()
     qWarning() << "OSM Offline tiles: "<<count;
 }
 
+QString QGeoFileTileCacheOsm::tileSpecToFilename(const QGeoTileSpec &spec, const QString &format, const QString &directory) const
+{
+    int providerId = spec.mapId() - 1;
+    if (providerId < 0 || providerId >= m_providers.size())
+        return QString();
+    QString filename = spec.plugin();
+    filename += QLatin1String("-");
+    filename += (m_providers[providerId]->isHighDpi()) ? QLatin1Char('h') : QLatin1Char('l');
+    filename += QLatin1String("-");
+    filename += QString::number(spec.mapId());
+    filename += QLatin1String("-");
+    filename += QString::number(spec.zoom());
+    filename += QLatin1String("-");
+    filename += QString::number(spec.x());
+    filename += QLatin1String("-");
+    filename += QString::number(spec.y());
+
+    //Append version if real version number to ensure backwards compatibility and eviction of old tiles
+    if (spec.version() != -1) {
+        filename += QLatin1String("-");
+        filename += QString::number(spec.version());
+    }
+
+    filename += QLatin1String(".");
+    filename += format;
+
+    QDir dir = QDir(directory);
+
+    return dir.filePath(filename);
+}
+
+QGeoTileSpec QGeoFileTileCacheOsm::filenameToTileSpec(const QString &filename) const
+{
+    QGeoTileSpec emptySpec;
+
+    QStringList parts = filename.split('.');
+
+    if (parts.length() != 2)
+        return emptySpec;
+
+    QString name = parts.at(0);
+    QStringList fields = name.split('-');
+
+    int length = fields.length();
+    if (length != 6 && length != 7)
+        return emptySpec;
+
+    QList<int> numbers;
+
+    bool ok = false;
+    for (int i = 2; i < length; ++i) {
+        ok = false;
+        int value = fields.at(i).toInt(&ok);
+        if (!ok)
+            return emptySpec;
+        numbers.append(value);
+    }
+
+    bool highDpi = m_providers[numbers.at(0) - 1]->isHighDpi();
+    if (highDpi && fields.at(1) != QLatin1Char('h'))
+        return emptySpec;
+    else if (!highDpi && fields.at(1) != QLatin1Char('l'))
+        return emptySpec;
+
+    //File name without version, append default
+    if (numbers.length() < 5)
+        numbers.append(-1);
+
+    return QGeoTileSpec(fields.at(0),
+                    numbers.at(0),
+                    numbers.at(1),
+                    numbers.at(2),
+                    numbers.at(3),
+                    numbers.at(4));
+}
+
 QT_END_NAMESPACE