Gui: allow change ExpressionCompleter filter mode

Fixes #4428

Filter mode set to Qt::MatchContains for tree view search and link
property editor object search.

Other usage of the completer (e.g. property editor, speadsheet) defaults
to Qt::MatchContains, but can be changed using parameter,

    BaseApp/Preferences/Expression/CompleterMatchExact

src/Gui/DlgPropertyLink.cpp

@@ -76,6 +76,7 @@ DlgPropertyLink::DlgPropertyLink(QWidget* parent)
     ui->typeTree->hide();
     ui->searchBox->installEventFilter(this);
     ui->searchBox->setNoProperty(true);
+    ui->searchBox->setMatchExact(false);
 
     timer = new QTimer(this);
     timer->setSingleShot(true);

src/Gui/ExpressionCompleter.cpp

@@ -537,7 +537,11 @@ ExpressionLineEdit::ExpressionLineEdit(QWidget *parent, bool noProperty)
     , block(true)
     , noProperty(noProperty)
 {
-    connect(this, SIGNAL(textChanged(const QString&)), this, SLOT(slotTextChanged(const QString&)));
+    auto handle = GetApplication().GetParameterGroupByPath(
+                "User parameter:BaseApp/Preferences/Expression");
+    matchExact = handle->GetBool("CompleterMatchExact", false);
+
+    connect(this, SIGNAL(textEdited(const QString&)), this, SLOT(slotTextChanged(const QString&)));
 }
 
 void ExpressionLineEdit::setDocumentObject(const App::DocumentObject * currentDocObj)
@@ -550,6 +554,10 @@ void ExpressionLineEdit::setDocumentObject(const App::DocumentObject * currentDo
         completer = new ExpressionCompleter(currentDocObj, this, noProperty);
         completer->setWidget(this);
         completer->setCaseSensitivity(Qt::CaseInsensitive);
+#if QT_VERSION>=QT_VERSION_CHECK(5,2,0)
+        if (!matchExact)
+            completer->setFilterMode(Qt::MatchContains);
+#endif
         connect(completer, SIGNAL(activated(QString)), this, SLOT(slotCompleteText(QString)));
         connect(completer, SIGNAL(highlighted(QString)), this, SLOT(slotCompleteText(QString)));
         connect(this, SIGNAL(textChanged2(QString,int)), completer, SLOT(slotUpdate(QString,int)));
@@ -562,6 +570,14 @@ void ExpressionLineEdit::setNoProperty(bool enabled) {
         completer->setNoProperty(enabled);
 }
 
+void ExpressionLineEdit::setMatchExact(bool enabled) {
+    matchExact = enabled;
+#if QT_VERSION>=QT_VERSION_CHECK(5,2,0)
+    if (completer)
+        completer->setFilterMode(matchExact ? Qt::MatchExactly : Qt::MatchContains);
+#endif
+}
+
 bool ExpressionLineEdit::completerActive() const
 {
     return completer && completer->popup() && completer->popup()->isVisible();
@@ -607,9 +623,21 @@ ExpressionTextEdit::ExpressionTextEdit(QWidget *parent)
     , completer(0)
     , block(true)
 {
+    auto handle = GetApplication().GetParameterGroupByPath(
+                "User parameter:BaseApp/Preferences/Expression");
+    matchExact = handle->GetBool("CompleterMatchExact", false);
+
     connect(this, SIGNAL(textChanged()), this, SLOT(slotTextChanged()));
 }
 
+void ExpressionTextEdit::setMatchExact(bool enabled) {
+    matchExact = enabled;
+#if QT_VERSION>=QT_VERSION_CHECK(5,2,0)
+    if (completer)
+        completer->setFilterMode(matchExact ? Qt::MatchExactly : Qt::MatchContains);
+#endif
+}
+
 void ExpressionTextEdit::setDocumentObject(const App::DocumentObject * currentDocObj)
 {
     if (completer) {
@@ -619,6 +647,10 @@ void ExpressionTextEdit::setDocumentObject(const App::DocumentObject * currentDo
 
     if (currentDocObj != 0) {
         completer = new ExpressionCompleter(currentDocObj, this);
+#if QT_VERSION>=QT_VERSION_CHECK(5,2,0)
+        if (!matchExact)
+            completer->setFilterMode(Qt::MatchContains);
+#endif
         completer->setWidget(this);
         completer->setCaseSensitivity(Qt::CaseInsensitive);
         connect(completer, SIGNAL(activated(QString)), this, SLOT(slotCompleteText(QString)));

src/Gui/ExpressionCompleter.h

@@ -68,6 +68,7 @@ class GuiExport ExpressionLineEdit : public QLineEdit {
     bool completerActive() const;
     void hideCompleter();
     void setNoProperty(bool enabled=true);
+    void setMatchExact(bool enabled=true);
 Q_SIGNALS:
     void textChanged2(QString text, int pos);
 public Q_SLOTS:
@@ -79,6 +80,7 @@ public Q_SLOTS:
     ExpressionCompleter * completer;
     bool block;
     bool noProperty;
+    bool matchExact;
 };
 
 class GuiExport ExpressionTextEdit : public QPlainTextEdit {
@@ -88,6 +90,7 @@ class GuiExport ExpressionTextEdit : public QPlainTextEdit {
     void setDocumentObject(const App::DocumentObject *currentDocObj);
     bool completerActive() const;
     void hideCompleter();
+    void setMatchExact(bool enabled=true);
 protected:
     void keyPressEvent(QKeyEvent * event);
 Q_SIGNALS:
@@ -98,6 +101,7 @@ public Q_SLOTS:
 private:
     ExpressionCompleter * completer;
     bool block;
+    bool matchExact;
 };
 
 }

src/Gui/Tree.cpp

@@ -2838,6 +2838,7 @@ TreePanel::TreePanel(const char *name, QWidget* parent)
             this, SLOT(showEditor()));
 
     this->searchBox = new Gui::ExpressionLineEdit(this,true);
+    static_cast<ExpressionLineEdit*>(this->searchBox)->setMatchExact(false);
     pLayout->addWidget(this->searchBox);
     this->searchBox->hide();
     this->searchBox->installEventFilter(this);