Qt: WLAN Statistics performance improvements.

In the WLAN statistics dialog, add our stations to the tree in the
background. This returns control to the user immediately after tapping.

Add notes about further performance improvements.

Change-Id: Ie7ff818b8d835ecb38f5ff702a0d0e8f2635abb2
Reviewed-on: https://code.wireshark.org/review/18495
Petri-Dish: Gerald Combs <gerald@wireshark.org>
Tested-by: Petri Dish Buildbot <buildbot-no-reply@wireshark.org>
Reviewed-by: Gerald Combs <gerald@wireshark.org>

2 files changed, 33 insertions, 3 deletions

diff --git a/ui/qt/wlan_statistics_dialog.cpp b/ui/qt/wlan_statistics_dialog.cpp
index 1040c4c999..4a3f18ccc9 100644
--- a/ui/qt/wlan_statistics_dialog.cpp
+++ b/ui/qt/wlan_statistics_dialog.cpp
@@ -27,6 +27,7 @@
 
 #include <epan/dissectors/packet-ieee80211.h>
 
+#include <QElapsedTimer>
 #include <QTreeWidget>
 #include <QTreeWidgetItem>
 
@@ -491,7 +492,9 @@ static const QString node_col_11_title_ = QObject::tr("Comment");
 
 WlanStatisticsDialog::WlanStatisticsDialog(QWidget &parent, CaptureFile &cf, const char *filter) :
     TapParameterDialog(parent, cf, HELP_STATS_WLAN_TRAFFIC_DIALOG),
-    packet_count_(0)
+    packet_count_(0),
+    cur_network_(0),
+    add_station_timer_(0)
 {
     setWindowSubtitle(tr("Wireless LAN Statistics"));
     loadGeometry(parent.width() * 4 / 5, parent.height() * 3 / 4, "WlanStatisticsDialog");
@@ -535,12 +538,15 @@ WlanStatisticsDialog::WlanStatisticsDialog(QWidget &parent, CaptureFile &cf, con
         setDisplayFilter(filter);
     }
 
+    add_station_timer_ = new QElapsedTimer();
+
     connect(statsTreeWidget(), SIGNAL(itemSelectionChanged()),
             this, SLOT(updateHeaderLabels()));
 }
 
 WlanStatisticsDialog::~WlanStatisticsDialog()
 {
+    delete add_station_timer_;
 }
 
 void WlanStatisticsDialog::tapReset(void *ws_dlg_ptr)
@@ -567,6 +573,8 @@ gboolean WlanStatisticsDialog::tapPacket(void *ws_dlg_ptr, _packet_info *, epan_
 
     ws_dlg->packet_count_++;
 
+    // XXX This is very slow for large numbers of networks. We might be
+    // able to store networks in a cache keyed on BSSID+SSID instead.
     WlanNetworkTreeWidgetItem *wn_ti = NULL;
     for (int i = 0; i < ws_dlg->statsTreeWidget()->topLevelItemCount(); i++) {
         QTreeWidgetItem *ti = ws_dlg->statsTreeWidget()->topLevelItem(i);
@@ -634,16 +642,32 @@ void WlanStatisticsDialog::fillTree()
         return;
     }
 
+    statsTreeWidget()->setSortingEnabled(false);
     cap_file_.retapPackets();
     tapDraw(this);
     removeTapListeners();
+    statsTreeWidget()->setSortingEnabled(true);
+
+    // Don't freeze if we have a large number of stations.
+    cur_network_ = 0;
+    QTimer::singleShot(0, this, SLOT(addStationTreeItems()));
+}
 
-    for (int i = 0; i < statsTreeWidget()->topLevelItemCount(); i++) {
-        QTreeWidgetItem *ti = statsTreeWidget()->topLevelItem(i);
+static const int add_station_interval_ = 5; // ms
+void WlanStatisticsDialog::addStationTreeItems()
+{
+    add_station_timer_->start();
+    while (add_station_timer_->elapsed() < add_station_interval_ && cur_network_ < statsTreeWidget()->topLevelItemCount()) {
+        QTreeWidgetItem *ti = statsTreeWidget()->topLevelItem(cur_network_);
         if (ti->type() != wlan_network_row_type_) continue;
 
         WlanNetworkTreeWidgetItem *wn_ti = static_cast<WlanNetworkTreeWidgetItem*>(ti);
         wn_ti->addStations();
+        ++cur_network_;
+    }
+
+    if (cur_network_ < statsTreeWidget()->topLevelItemCount()) {
+        QTimer::singleShot(0, this, SLOT(addStationTreeItems()));
     }
 }
 
diff --git a/ui/qt/wlan_statistics_dialog.h b/ui/qt/wlan_statistics_dialog.h
index e39f4b6427..670feda3b1 100644
--- a/ui/qt/wlan_statistics_dialog.h
+++ b/ui/qt/wlan_statistics_dialog.h
@@ -24,6 +24,8 @@
 
 #include "tap_parameter_dialog.h"
 
+class QElapsedTimer;
+
 class WlanStatisticsDialog : public TapParameterDialog
 {
     Q_OBJECT
@@ -36,6 +38,9 @@ protected:
 
 private:
     int packet_count_;
+    int cur_network_;
+    QElapsedTimer *add_station_timer_;
+
 
     // Callbacks for register_tap_listener
     static void tapReset(void *ws_dlg_ptr);
@@ -46,6 +51,7 @@ private:
 
 private slots:
     virtual void fillTree();
+    void addStationTreeItems();
     void updateHeaderLabels();
     void captureFileClosing();
 };