[LyX/master] GuiSymbols: Better handling of empty blocks

[Guillaume Munch]

commit ee0e95aafb99bbc29818f95b7654c9a3a72f167b
Author: Guillaume Munch <g...@lyx.org>
Date:   Sat Dec 3 23:35:15 2016 +0100

    GuiSymbols: Better handling of empty blocks
    
    * endInsertRow was incorrectly placed before endResetModel, sometimes 
leading to
      bad access by the view before it was informed that the model was empty. In
      fact begin/endInsertRows were redundant with begin/endResetModel.
    
    * Empty blocks are not supposed to be shown. This happened when moving the
      cursor. A valid block is now selected intead. Due to the 
design/optimisation
      of the model update, this requires a first update with an empty
      model. Simplify the old code.
---
 src/frontends/qt4/GuiSymbols.cpp |   24 ++++++++++--------------
 1 files changed, 10 insertions(+), 14 deletions(-)

diff --git a/src/frontends/qt4/GuiSymbols.cpp b/src/frontends/qt4/GuiSymbols.cpp
index 4b314e8..145a2d2 100644
--- a/src/frontends/qt4/GuiSymbols.cpp
+++ b/src/frontends/qt4/GuiSymbols.cpp
@@ -256,10 +256,8 @@ public:
        void setSymbols(QList<char_type> const & symbols, Encoding const * 
encoding)
        {
                beginResetModel();
-               beginInsertRows(QModelIndex(), 0, symbols.size() - 1);
                symbols_ = symbols;
                encoding_ = encoding;
-               endInsertRows();
                endResetModel();
        }
 
@@ -420,8 +418,7 @@ void GuiSymbols::scrollToItem(QString const & category)
 
 void GuiSymbols::updateSymbolList(bool update_combo)
 {
-       QString category = categoryCO->currentText();
-       bool const nocategory = category.isEmpty();
+       QString const category = categoryCO->currentText();
        char_type range_start = 0x0000;
        char_type range_end = 0x110000;
        QList<char_type> s;
@@ -445,11 +442,9 @@ void GuiSymbols::updateSymbolList(bool update_combo)
                        }
        }
 
-       SymbolsList::const_iterator const end = symbols_.end();
        int numItem = 0;
-       for (SymbolsList::const_iterator it = symbols_.begin(); it != end; 
++it) {
-               char_type c = *it;
-               if (!update_combo && !show_all && (c <= range_start || c >= 
range_end))
+       for (char_type c : symbols_) {
+               if (!update_combo && !show_all && (c < range_start || c > 
range_end))
                        continue;
                QChar::Category const cat = QChar::category(uint(c));
                // we do not want control or space characters
@@ -460,8 +455,6 @@ void GuiSymbols::updateSymbolList(bool update_combo)
                        s.append(c);
                if (update_combo) {
                        QString block = getBlock(c);
-                       if (category.isEmpty())
-                               category = block;
                        if (used_blocks.find(block) == used_blocks.end())
                                used_blocks[block] = numItem;
                }
@@ -479,10 +472,13 @@ void GuiSymbols::updateSymbolList(bool update_combo)
        int old = categoryCO->findText(category);
        if (old != -1)
                categoryCO->setCurrentIndex(old);
-       // update again in case the combo has not yet been filled
-       // on first cycle (at dialog initialization)
-       if (nocategory && !category.isEmpty())
-               updateSymbolList();
+       else if (update_combo) {
+               // restart with a non-empty block
+               // this happens when the encoding changes when moving the cursor
+               categoryCO->setCurrentIndex(0);
+               updateSymbolList(false);
+               return;
+       }
 }