Add "Coalesce reads & writes" checkbox in advanced options

The setting is defaulted to ON for Windows. Closes #8295.

src/base/bittorrent/session.cpp

@@ -280,6 +280,11 @@ Session::Session(QObject *parent)
     , m_diskCacheTTL(BITTORRENT_SESSION_KEY("DiskCacheTTL"), 60)
     , m_useOSCache(BITTORRENT_SESSION_KEY("UseOSCache"), true)
     , m_guidedReadCacheEnabled(BITTORRENT_SESSION_KEY("GuidedReadCache"), true)
+#ifdef Q_OS_WIN
+    , m_coalesceReadWriteEnabled(BITTORRENT_SESSION_KEY("CoalesceReadWrite"), true)
+#else
+    , m_coalesceReadWriteEnabled(BITTORRENT_SESSION_KEY("CoalesceReadWrite"), false)
+#endif
     , m_isSuggestMode(BITTORRENT_SESSION_KEY("SuggestMode"), false)
     , m_sendBufferWatermark(BITTORRENT_SESSION_KEY("SendBufferWatermark"), 500)
     , m_sendBufferLowWatermark(BITTORRENT_SESSION_KEY("SendBufferLowWatermark"), 10)
@@ -1303,6 +1308,10 @@ void Session::configure(libtorrent::settings_pack &settingsPack)
     settingsPack.set_int(libt::settings_pack::disk_io_read_mode, mode);
     settingsPack.set_int(libt::settings_pack::disk_io_write_mode, mode);
     settingsPack.set_bool(libt::settings_pack::guided_read_cache, isGuidedReadCacheEnabled());
+
+    settingsPack.set_bool(libt::settings_pack::coalesce_reads, isCoalesceReadWriteEnabled());
+    settingsPack.set_bool(libt::settings_pack::coalesce_writes, isCoalesceReadWriteEnabled());
+
     settingsPack.set_int(libt::settings_pack::suggest_mode, isSuggestModeEnabled()
                          ? libt::settings_pack::suggest_read_cache : libt::settings_pack::no_piece_suggestions);
 
@@ -3049,6 +3058,19 @@ void Session::setGuidedReadCacheEnabled(bool enabled)
     configureDeferred();
 }
 
+bool Session::isCoalesceReadWriteEnabled() const
+{
+    return m_coalesceReadWriteEnabled;
+}
+
+void Session::setCoalesceReadWriteEnabled(bool enabled)
+{
+    if (enabled == m_coalesceReadWriteEnabled) return;
+
+    m_coalesceReadWriteEnabled = enabled;
+    configureDeferred();
+}
+
 bool Session::isSuggestModeEnabled() const
 {
     return m_isSuggestMode;

src/base/bittorrent/session.h

@@ -382,6 +382,8 @@ namespace BitTorrent
         void setUseOSCache(bool use);
         bool isGuidedReadCacheEnabled() const;
         void setGuidedReadCacheEnabled(bool enabled);
+        bool isCoalesceReadWriteEnabled() const;
+        void setCoalesceReadWriteEnabled(bool enabled);
         bool isSuggestModeEnabled() const;
         void setSuggestMode(bool mode);
         int sendBufferWatermark() const;
@@ -646,6 +648,7 @@ namespace BitTorrent
         CachedSettingValue<int> m_diskCacheTTL;
         CachedSettingValue<bool> m_useOSCache;
         CachedSettingValue<bool> m_guidedReadCacheEnabled;
+        CachedSettingValue<bool> m_coalesceReadWriteEnabled;
         CachedSettingValue<bool> m_isSuggestMode;
         CachedSettingValue<int> m_sendBufferWatermark;
         CachedSettingValue<int> m_sendBufferLowWatermark;

src/gui/advancedsettings.cpp

@@ -82,6 +82,7 @@ enum AdvSettingsRows
     DISK_CACHE_TTL,
     OS_CACHE,
     GUIDED_READ_CACHE,
+    COALESCE_RW,
     SUGGEST_MODE,
     SEND_BUF_WATERMARK,
     SEND_BUF_LOW_WATERMARK,
@@ -142,6 +143,8 @@ void AdvancedSettings::saveAdvancedSettings()
     session->setUseOSCache(cb_os_cache.isChecked());
     // Guided read cache
     session->setGuidedReadCacheEnabled(cbGuidedReadCache.isChecked());
+    // Coalesce reads & writes
+    session->setCoalesceReadWriteEnabled(cbCoalesceRW.isChecked());
     // Suggest mode
     session->setSuggestMode(cbSuggestMode.isChecked());
     // Send buffer watermark
@@ -313,6 +316,11 @@ void AdvancedSettings::loadAdvancedSettings()
     // Guided read cache
     cbGuidedReadCache.setChecked(session->isGuidedReadCacheEnabled());
     addRow(GUIDED_READ_CACHE, tr("Guided read cache"), &cbGuidedReadCache);
+    // Coalesce reads & writes
+    cbCoalesceRW.setChecked(session->isCoalesceReadWriteEnabled());
+#if LIBTORRENT_VERSION_NUM >= 10107
+    addRow(COALESCE_RW, tr("Coalesce reads & writes"), &cbCoalesceRW);
+#endif
     // Suggest mode
     cbSuggestMode.setChecked(session->isSuggestModeEnabled());
     addRow(SUGGEST_MODE, tr("Send upload piece suggestions"), &cbSuggestMode);

src/gui/advancedsettings.h

@@ -80,7 +80,7 @@ private:
     QCheckBox cb_os_cache, cb_recheck_completed, cb_resolve_countries, cb_resolve_hosts, cb_super_seeding,
               cb_program_notifications, cb_torrent_added_notifications, cb_tracker_favicon, cb_tracker_status,
               cb_confirm_torrent_recheck, cb_confirm_remove_all_tags, cb_listen_ipv6, cb_announce_all_trackers, cb_announce_all_tiers,
-              cbGuidedReadCache, cbMultiConnectionsPerIp, cbSuggestMode;
+              cbGuidedReadCache, cbMultiConnectionsPerIp, cbSuggestMode, cbCoalesceRW;
     QComboBox combo_iface, combo_iface_address, comboUtpMixedMode, comboChokingAlgorithm, comboSeedChokingAlgorithm;
     QLineEdit txtAnnounceIP;