Provide way to show a variable chooser widget.

For the Qt Creator variables, currently used in the external tools.
The variable chooser looks if the current focus widget has a variable
support property set and is a line edit, text edit or plain text edit.
For line edits it adds a little icon button that shows the chooser.

src/plugins/coreplugin/variablechooser.cpp

@@ -34,6 +34,7 @@
 #include "variablechooser.h"
 #include "ui_variablechooser.h"
 #include "variablemanager.h"
+#include "coreconstants.h"
 
 using namespace Core;
 
@@ -44,7 +45,6 @@ VariableChooser::VariableChooser(QWidget *parent) :
     m_textEdit(0),
     m_plainTextEdit(0)
 {
-    setAttribute(Qt::WA_DeleteOnClose);
     ui->setupUi(this);
     m_defaultDescription = ui->variableDescription->text();
     ui->variableList->setAttribute(Qt::WA_MacSmallSize);
@@ -63,12 +63,13 @@ VariableChooser::VariableChooser(QWidget *parent) :
     connect(ui->variableList, SIGNAL(itemActivated(QListWidgetItem*)),
             this, SLOT(handleItemActivated(QListWidgetItem*)));
     connect(qApp, SIGNAL(focusChanged(QWidget*,QWidget*)),
-            this, SLOT(updateCurrentEditor(QWidget*)));
-    updateCurrentEditor(qApp->focusWidget());
+            this, SLOT(updateCurrentEditor(QWidget*,QWidget*)));
+    updateCurrentEditor(0, qApp->focusWidget());
 }
 
 VariableChooser::~VariableChooser()
 {
+    delete m_iconButton;
     delete ui;
 }
 
@@ -80,21 +81,70 @@ void VariableChooser::updateDescription(const QString &variable)
         ui->variableDescription->setText(VariableManager::instance()->variableDescription(variable));
 }
 
-void VariableChooser::updateCurrentEditor(QWidget *widget)
+void VariableChooser::updateCurrentEditor(QWidget *old, QWidget *widget)
 {
-    if (QLineEdit *lineEdit = qobject_cast<QLineEdit *>(widget)) {
-        m_lineEdit = lineEdit;
-        m_textEdit = 0;
-        m_plainTextEdit = 0;
-    } else if (QTextEdit *textEdit = qobject_cast<QTextEdit *>(widget)) {
-        m_lineEdit = 0;
-        m_textEdit = textEdit;
-        m_plainTextEdit = 0;
-    } else if (QPlainTextEdit *plainTextEdit = qobject_cast<QPlainTextEdit *>(widget)) {
-        m_lineEdit = 0;
-        m_textEdit = 0;
-        m_plainTextEdit = plainTextEdit;
+    Q_UNUSED(old)
+    if (!widget) // we might loose focus, but then keep the previous state
+        return;
+    // prevent children of the chooser itself, and limit to children of chooser's parent
+    bool handle = false;
+    QWidget *parent = widget;
+    while (parent) {
+        if (parent == this)
+            return;
+        if (parent == this->parentWidget()) {
+            handle = true;
+            break;
+        }
+        parent = parent->parentWidget();
     }
+    if (!handle)
+        return;
+    QLineEdit *previousLineEdit = m_lineEdit;
+    m_lineEdit = 0;
+    m_textEdit = 0;
+    m_plainTextEdit = 0;
+    QVariant variablesSupportProperty = variablesSupportProperty = widget->property(Constants::VARIABLE_SUPPORT_PROPERTY);
+    bool supportsVariables = (variablesSupportProperty.isValid()
+                              ? variablesSupportProperty.toBool() : false);
+    if (QLineEdit *lineEdit = qobject_cast<QLineEdit *>(widget)) {
+        m_lineEdit = (supportsVariables ? lineEdit : 0);
+    } else if (QTextEdit *textEdit = qobject_cast<QTextEdit *>(widget)) {
+        m_textEdit = (supportsVariables ? textEdit : 0);
+    } else if (QPlainTextEdit *plainTextEdit = qobject_cast<QPlainTextEdit *>(widget)) {
+        m_plainTextEdit = (supportsVariables ? plainTextEdit : 0);
+    }
+    if (!(m_lineEdit || m_textEdit || m_plainTextEdit))
+        hide();
+    if (m_lineEdit != previousLineEdit) {
+        if (previousLineEdit)
+            previousLineEdit->setTextMargins(0, 0, 0, 0);
+        if (m_iconButton) {
+            m_iconButton->hide();
+            m_iconButton->setParent(0);
+        }
+        if (m_lineEdit) {
+            if (!m_iconButton)
+                createIconButton();
+            int margin = m_iconButton->pixmap().width() + 8;
+            if (style()->inherits("OxygenStyle"))
+                margin = qMax(24, margin);
+            m_lineEdit->setTextMargins(0, 0, margin, 0);
+            m_iconButton->setParent(m_lineEdit);
+            m_iconButton->setGeometry(m_lineEdit->rect().adjusted(
+                                          m_lineEdit->width() - (margin + 4), 0, 0, 0));
+            m_iconButton->show();
+        }
+    }
+}
+
+void VariableChooser::createIconButton()
+{
+    m_iconButton = new Utils::IconButton;
+    m_iconButton->setPixmap(QPixmap(QLatin1String(":/core/images/replace.png")));
+    m_iconButton->setToolTip(tr("Insert variable"));
+    m_iconButton->hide();
+    connect(m_iconButton, SIGNAL(clicked()), this, SLOT(show()));
 }
 
 void VariableChooser::handleItemActivated(QListWidgetItem *item)
@@ -108,9 +158,12 @@ void VariableChooser::insertVariable(const QString &variable)
     const QString &text = QLatin1String("${") + variable + QLatin1String("}");
     if (m_lineEdit) {
         m_lineEdit->insert(text);
+        m_lineEdit->activateWindow();
     } else if (m_textEdit) {
         m_textEdit->insertPlainText(text);
+        m_textEdit->activateWindow();
     } else if (m_plainTextEdit) {
         m_plainTextEdit->insertPlainText(text);
+        m_plainTextEdit->activateWindow();
     }
 }