Qt: Add idle dissection.

Features such as sorting and scroll bar colorization require
fully-dissected packets. We currently do dissection at the wrong time --
*after* the user clicks on a packet list column header or moves the
scrollbar.

Add a timer + slot that dissects packets when the UI is idle so that our
packets are at least partially dissected when we need them.

Change-Id: I024c590af2250d67404a520f118e46ec0c49cd71
Reviewed-on: https://code.wireshark.org/review/10593
Petri-Dish: Gerald Combs <gerald@wireshark.org>
Tested-by: Petri Dish Buildbot <buildbot-no-reply@wireshark.org>
Reviewed-by: Gerald Combs <gerald@wireshark.org>

ui/qt/packet_list.cpp

@@ -735,6 +735,7 @@ void PacketList::setAutoScroll(bool enabled)
 void PacketList::captureFileReadFinished()
 {
     packet_list_model_->flushVisibleRows();
+    packet_list_model_->dissectIdle(true);
 }
 
 void PacketList::freeze()

ui/qt/packet_list_model.cpp

@@ -40,6 +40,7 @@
 #include "wireshark_application.h"
 
 #include <QColor>
+#include <QElapsedTimer>
 #include <QFontMetrics>
 #include <QModelIndex>
 #include <QElapsedTimer>
@@ -48,13 +49,20 @@ PacketListModel::PacketListModel(QObject *parent, capture_file *cf) :
     QAbstractItemModel(parent),
     uniform_row_heights_(true),
     row_height_(-1),
-    line_spacing_(0)
+    line_spacing_(0),
+    idle_dissection_row_(0)
 {
     setCaptureFile(cf);
     PacketListRecord::clearStringPool();
     connect(this, SIGNAL(itemHeightChanged(QModelIndex)),
             this, SLOT(emitItemHeightChanged(QModelIndex)),
             Qt::QueuedConnection);
+    idle_dissection_timer_ = new QElapsedTimer();
+}
+
+PacketListModel::~PacketListModel()
+{
+    delete idle_dissection_timer_;
 }
 
 void PacketListModel::setCaptureFile(capture_file *cf)
@@ -103,6 +111,7 @@ guint PacketListModel::recreateVisibleRows()
     }
     endInsertRows();
     return visible_rows_.count();
+    idle_dissection_row_ = 0;
 }
 
 void PacketListModel::clear() {
@@ -114,6 +123,7 @@ void PacketListModel::clear() {
     PacketListRecord::clearStringPool();
     endResetModel();
     uniform_row_heights_ = true;
+    idle_dissection_row_ = 0;
 }
 
 void PacketListModel::resetColumns()
@@ -532,6 +542,34 @@ void PacketListModel::flushVisibleRows()
     }
 }
 
+// Fill our column string and colorization cache while the application is
+// idle. Try to be as conservative with the CPU and disk as possible.
+static const int idle_dissection_interval_ = 5; // ms
+void PacketListModel::dissectIdle(bool reset)
+{
+    if (reset) {
+//        qDebug() << "=di reset" << idle_dissection_row_;
+        idle_dissection_row_ = 0;
+    } else if (!idle_dissection_timer_->isValid()) {
+        return;
+    }
+
+    idle_dissection_timer_->restart();
+
+    while (idle_dissection_timer_->elapsed() < idle_dissection_interval_
+           && idle_dissection_row_ < physical_rows_.count()) {
+        ensureRowColorized(idle_dissection_row_);
+        idle_dissection_row_++;
+//        if (idle_dissection_row_ % 1000 == 0) qDebug() << "=di row" << idle_dissection_row_;
+    }
+
+    if (idle_dissection_row_ < physical_rows_.count()) {
+        QTimer::singleShot(idle_dissection_interval_, this, SLOT(dissectIdle()));
+    } else {
+        idle_dissection_timer_->invalidate();
+    }
+}
+
 // XXX Pass in cinfo from packet_list_append so that we can fill in
 // line counts?
 gint PacketListModel::appendPacket(frame_data *fdata)

ui/qt/packet_list_model.h

@@ -38,11 +38,14 @@
 
 #include "cfile.h"
 
+class QElapsedTimer;
+
 class PacketListModel : public QAbstractItemModel
 {
     Q_OBJECT
 public:
     explicit PacketListModel(QObject *parent = 0, capture_file *cf = NULL);
+    ~PacketListModel();
     void setCaptureFile(capture_file *cf);
     QModelIndex index(int row, int column,
                       const QModelIndex & = QModelIndex()) const;
@@ -86,6 +89,7 @@ public slots:
     void setMonospaceFont(const QFont &mono_font, int row_height);
     void sort(int column, Qt::SortOrder order = Qt::AscendingOrder);
     void flushVisibleRows();
+    void dissectIdle(bool reset = false);
 
 private:
     capture_file *cap_file_;
@@ -106,6 +110,10 @@ private:
     static capture_file *sort_cap_file_;
     static bool recordLessThan(PacketListRecord *r1, PacketListRecord *r2);
 
+    QElapsedTimer *idle_dissection_timer_;
+    int idle_dissection_row_;
+
+
 private slots:
     void emitItemHeightChanged(const QModelIndex &ih_index);
 };