Don't use removed stat metric in libtorrent 2.0

For now, the metric is not entirely removed due to WebAPI still needs to
access it.

src/base/bittorrent/cachestatus.h

@@ -38,6 +38,6 @@ namespace BitTorrent
         quint64 jobQueueLength = 0;
         quint64 averageJobTime = 0;
         quint64 queuedBytes = 0;
-        qreal readRatio = 0.0;
+        qreal readRatio = 0;  // TODO: remove when LIBTORRENT_VERSION_NUM >= 20000
     };
 }

src/base/bittorrent/session.cpp

@@ -1220,8 +1220,10 @@ void Session::initMetrics()
     m_metricIndices.disk.numBlocksRead = lt::find_metric_idx("disk.num_blocks_read");
     Q_ASSERT(m_metricIndices.disk.numBlocksRead >= 0);
 
+#if (LIBTORRENT_VERSION_NUM < 20000)
     m_metricIndices.disk.numBlocksCacheHits = lt::find_metric_idx("disk.num_blocks_cache_hits");
     Q_ASSERT(m_metricIndices.disk.numBlocksCacheHits >= 0);
+#endif
 
     m_metricIndices.disk.writeJobs = lt::find_metric_idx("disk.num_write_ops");
     Q_ASSERT(m_metricIndices.disk.writeJobs >= 0);
@@ -4908,11 +4910,14 @@ void Session::handleSessionStatsAlert(const lt::session_stats_alert *p)
     m_status.peersCount = stats[m_metricIndices.peer.numPeersConnected];
 
     const int64_t numBlocksRead = stats[m_metricIndices.disk.numBlocksRead];
-    const int64_t numBlocksCacheHits = stats[m_metricIndices.disk.numBlocksCacheHits];
     m_cacheStatus.totalUsedBuffers = stats[m_metricIndices.disk.diskBlocksInUse];
-    m_cacheStatus.readRatio = static_cast<qreal>(numBlocksCacheHits) / std::max<int64_t>(numBlocksCacheHits + numBlocksRead, 1);
     m_cacheStatus.jobQueueLength = stats[m_metricIndices.disk.queuedDiskJobs];
 
+#if (LIBTORRENT_VERSION_NUM < 20000)
+    const int64_t numBlocksCacheHits = stats[m_metricIndices.disk.numBlocksCacheHits];
+    m_cacheStatus.readRatio = static_cast<qreal>(numBlocksCacheHits) / std::max<int64_t>((numBlocksCacheHits + numBlocksRead), 1);
+#endif
+
     const int64_t totalJobs = stats[m_metricIndices.disk.writeJobs] + stats[m_metricIndices.disk.readJobs]
                   + stats[m_metricIndices.disk.hashJobs];
     m_cacheStatus.averageJobTime = (totalJobs > 0)

src/base/bittorrent/session.h

@@ -197,7 +197,9 @@ namespace BitTorrent
         {
             int diskBlocksInUse = -1;
             int numBlocksRead = -1;
+#if (LIBTORRENT_VERSION_NUM < 20000)
             int numBlocksCacheHits = -1;
+#endif
             int writeJobs = -1;
             int readJobs = -1;
             int hashJobs = -1;

src/gui/statsdialog.cpp

@@ -52,6 +52,11 @@ StatsDialog::StatsDialog(QWidget *parent)
     connect(BitTorrent::Session::instance(), &BitTorrent::Session::statsUpdated
             , this, &StatsDialog::update);
 
+#if (LIBTORRENT_VERSION_NUM >= 20000)
+    m_ui->labelCacheHitsText->hide();
+    m_ui->labelCacheHits->hide();
+#endif
+
     Utils::Gui::resize(this);
     show();
 }
@@ -78,11 +83,13 @@ void StatsDialog::update()
                 ((atd > 0) && (atu > 0))
                 ? Utils::String::fromDouble(static_cast<qreal>(atu) / atd, 2)
                 : "-");
+#if (LIBTORRENT_VERSION_NUM < 20000)
     // Cache hits
-    qreal readRatio = cs.readRatio;
+    const qreal readRatio = cs.readRatio;
     m_ui->labelCacheHits->setText(QString::fromLatin1("%1%").arg((readRatio > 0)
         ? Utils::String::fromDouble(100 * readRatio, 2)
         : QLatin1String("0")));
+#endif
     // Buffers size
     m_ui->labelTotalBuf->setText(Utils::Misc::friendlyUnit(cs.totalUsedBuffers * 16 * 1024));
     // Disk overload (100%) equivalent

src/gui/statsdialog.h

@@ -35,7 +35,7 @@ namespace Ui
     class StatsDialog;
 }
 
-class StatsDialog : public QDialog
+class StatsDialog final : public QDialog
 {
     Q_OBJECT
 

src/webui/api/synccontroller.cpp

@@ -134,7 +134,7 @@ namespace
         map[KEY_TRANSFER_GLOBAL_RATIO] = ((atd > 0) && (atu > 0)) ? Utils::String::fromDouble(static_cast<qreal>(atu) / atd, 2) : "-";
         map[KEY_TRANSFER_TOTAL_PEER_CONNECTIONS] = sessionStatus.peersCount;
 
-        const qreal readRatio = cacheStatus.readRatio;
+        const qreal readRatio = cacheStatus.readRatio;  // TODO: remove when LIBTORRENT_VERSION_NUM >= 20000
         map[KEY_TRANSFER_READ_CACHE_HITS] = (readRatio > 0) ? Utils::String::fromDouble(100 * readRatio, 2) : "0";
         map[KEY_TRANSFER_TOTAL_BUFFERS_SIZE] = cacheStatus.totalUsedBuffers * 16 * 1024;