Qt: Fix packet list column resizing.

The size hint changes in g5ab8490 broke packet list column resizing. Add
back a way to force the hinting necessary for sizeHintForColumn to work
properly.

Bug: 11067
Ping-Bug: 10924
Change-Id: Icd525200f7a88f2b6d22a3039cda98ad0527239e
Reviewed-on: https://code.wireshark.org/review/8334
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

@@ -55,6 +55,7 @@
 #include <QAction>
 #include <QActionGroup>
 #include <QContextMenuEvent>
+#include <QFontMetrics>
 #include <QHeaderView>
 #include <QMessageBox>
 #include <QScrollBar>
@@ -591,6 +592,18 @@ void PacketList::setColumnVisibility()
     }
 }
 
+int PacketList::sizeHintForColumn(int column) const
+{
+    int size_hint;
+
+    // This is a bit hacky but Qt does a fine job of column sizing and
+    // reimplementing QTreeView::sizeHintForColumn seems worse.
+    packet_list_model_->setSizeHintEnabled(false);
+    size_hint = QTreeView::sizeHintForColumn(column);
+    packet_list_model_->setSizeHintEnabled(true);
+    return size_hint;
+}
+
 void PacketList::initHeaderContextMenu()
 {
     header_ctx_menu_.clear();
@@ -670,12 +683,13 @@ void PacketList::applyRecentColumnWidths()
             fmt = get_column_format(i);
             long_str = get_column_width_string(fmt, i);
             if (long_str) {
-                col_width = packet_list_model_->columnTextSize(long_str);
+                col_width = fontMetrics().width(long_str);
             } else {
-                col_width = packet_list_model_->columnTextSize(MIN_COL_WIDTH_STR);
+                col_width = fontMetrics().width(MIN_COL_WIDTH_STR);
             }
         }
-        setColumnWidth(i, col_width);
+        col_width += QTreeView::sizeHintForColumn(i); // Decoration padding
+        setColumnWidth(i, col_width) ;
     }
     column_state_ = header()->saveState();
     redrawVisiblePackets();

ui/qt/packet_list.h

@@ -104,6 +104,7 @@ private:
     void setFrameIgnore(gboolean set, frame_data *fdata);
     void setFrameReftime(gboolean set, frame_data *fdata);
     void setColumnVisibility();
+    int sizeHintForColumn(int column) const;
     void initHeaderContextMenu();
 signals:
     void packetDissectionChanged();

ui/qt/packet_list_model.cpp

@@ -39,6 +39,7 @@
 
 PacketListModel::PacketListModel(QObject *parent, capture_file *cf) :
     QAbstractItemModel(parent),
+    size_hint_enabled_(true),
     row_height_(-1),
     line_spacing_(0)
 {
@@ -127,13 +128,6 @@ void PacketListModel::resetColorized()
     endResetModel();
 }
 
-int PacketListModel::columnTextSize(const char *str)
-{
-    QFontMetrics fm(mono_font_);
-
-    return fm.width(str);
-}
-
 void PacketListModel::setMonospaceFont(const QFont &mono_font, int row_height)
 {
     QFontMetrics fm(mono_font_);
@@ -331,9 +325,14 @@ QVariant PacketListModel::data(const QModelIndex &index, int role) const
     }
     case Qt::SizeHintRole:
     {
-        // We assume that inter-line spacing is 0.
-        QSize size = QSize(-1, row_height_ + ((record->lineCount() - 1) * line_spacing_));
-        return size;
+        if (size_hint_enabled_) {
+            // We assume that inter-line spacing is 0.
+            QSize size = QSize(-1, row_height_ + ((record->lineCount() - 1) * line_spacing_));
+            return size;
+        } else {
+            // Used by PacketList::sizeHintForColumn
+            return QVariant();
+        }
     }
     default:
         return QVariant();

ui/qt/packet_list_model.h

@@ -62,7 +62,7 @@ public:
     int visibleIndexOf(frame_data *fdata) const;
     void resetColumns();
     void resetColorized();
-    int columnTextSize(const char *str);
+    void setSizeHintEnabled(bool enable) { size_hint_enabled_ = enable; }
 
 signals:
     void goToPacket(int);
@@ -80,6 +80,7 @@ private:
     QVector<PacketListRecord *> physical_rows_;
     QMap<int, int> number_to_row_;
 
+    bool size_hint_enabled_;
     int row_height_;
     int line_spacing_;