cppcodecompletion.cpp

/**************************************************************************
**
** This file is part of Qt Creator
**
** Copyright (c) 2010 Nokia Corporation and/or its subsidiary(-ies).
**
** Contact: Nokia Corporation (qt-info@nokia.com)
**
** Commercial Usage
**
** Licensees holding valid Qt Commercial licenses may use this file in
** accordance with the Qt Commercial License Agreement provided with the
** Software or, alternatively, in accordance with the terms contained in
** a written agreement between you and Nokia.
**
** GNU Lesser General Public License Usage
**
** Alternatively, this file may be used under the terms of the GNU Lesser
** General Public License version 2.1 as published by the Free Software
** Foundation and appearing in the file LICENSE.LGPL included in the
** packaging of this file.  Please review the following information to
** ensure the GNU Lesser General Public License version 2.1 requirements
** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
**
** If you are unsure which license is appropriate for your use, please
** contact the sales department at http://qt.nokia.com/contact.
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**************************************************************************/

#include "cppcodecompletion.h"
#include "cppmodelmanager.h"
#include "cppdoxygen.h"
#include "cpptoolsconstants.h"
#include "cpptoolseditorsupport.h"

#include <Control.h>
#include <AST.h>
#include <ASTVisitor.h>
#include <CoreTypes.h>
#include <Literals.h>
#include <Names.h>
#include <NameVisitor.h>
#include <Symbols.h>
#include <SymbolVisitor.h>
#include <Scope.h>
#include <TranslationUnit.h>

#include <cplusplus/ResolveExpression.h>
#include <cplusplus/MatchingText.h>
#include <cplusplus/Overview.h>
#include <cplusplus/ExpressionUnderCursor.h>
#include <cplusplus/BackwardsScanner.h>
#include <cplusplus/LookupContext.h>

#include <coreplugin/icore.h>
#include <coreplugin/mimedatabase.h>
#include <coreplugin/editormanager/editormanager.h>
#include <texteditor/completionsettings.h>
#include <texteditor/itexteditor.h>
#include <texteditor/itexteditable.h>
#include <texteditor/basetexteditor.h>
#include <projectexplorer/projectexplorer.h>

#include <utils/faketooltip.h>
#include <utils/qtcassert.h>

#include <QtCore/QMap>
#include <QtCore/QFile>
#include <QtGui/QAction>
#include <QtGui/QApplication>
#include <QtGui/QDesktopWidget>
#include <QtGui/QKeyEvent>
#include <QtGui/QLabel>
#include <QtGui/QStyle>
#include <QtGui/QTextDocument> // Qt::escape()
#include <QtGui/QToolButton>
#include <QtGui/QVBoxLayout>

namespace {
    const bool debug = ! qgetenv("CPLUSPLUS_DEBUG").isEmpty();
}

using namespace CPlusPlus;

namespace CppTools {
namespace Internal {

class FunctionArgumentWidget : public QLabel
{
    Q_OBJECT

public:
    FunctionArgumentWidget();
    void showFunctionHint(QList<Function *> functionSymbols,
                          const LookupContext &context,
                          int startPosition);

protected:
    bool eventFilter(QObject *obj, QEvent *e);

private slots:
    void nextPage();
    void previousPage();

private:
    void updateArgumentHighlight();
    void updateHintText();

    Function *currentFunction() const
    { return m_items.at(m_current); }

    int m_startpos;
    int m_currentarg;
    int m_current;
    bool m_escapePressed;

    TextEditor::ITextEditor *m_editor;

    QWidget *m_pager;
    QLabel *m_numberLabel;
    Utils::FakeToolTip *m_popupFrame;
    QList<Function *> m_items;
    LookupContext m_context;
};

class ConvertToCompletionItem: protected NameVisitor
{
    // The completion collector.
    CppCodeCompletion *_collector;

    // The completion item.
    TextEditor::CompletionItem _item;

    // The current symbol.
    Symbol *_symbol;

    // The pretty printer.
    Overview overview;

public:
    ConvertToCompletionItem(CppCodeCompletion *collector)
        : _collector(collector),
          _item(0),
          _symbol(0)
    { }

    TextEditor::CompletionItem operator()(Symbol *symbol)
    {
        if (! symbol || ! symbol->name() || symbol->name()->isQualifiedNameId())
            return 0;

        TextEditor::CompletionItem previousItem = switchCompletionItem(0);
        Symbol *previousSymbol = switchSymbol(symbol);
        accept(symbol->identity());
        if (_item)
            _item.data = QVariant::fromValue(symbol);
        (void) switchSymbol(previousSymbol);
        return switchCompletionItem(previousItem);
    }

protected:
    Symbol *switchSymbol(Symbol *symbol)
    {
        Symbol *previousSymbol = _symbol;
        _symbol = symbol;
        return previousSymbol;
    }

    TextEditor::CompletionItem switchCompletionItem(TextEditor::CompletionItem item)
    {
        TextEditor::CompletionItem previousItem = _item;
        _item = item;
        return previousItem;
    }

    TextEditor::CompletionItem newCompletionItem(const Name *name)
    {
        TextEditor::CompletionItem item(_collector);
        item.text = overview.prettyName(name);
        item.icon = _collector->iconForSymbol(_symbol);
        return item;
    }

    virtual void visit(const NameId *name)
    { _item = newCompletionItem(name); }

    virtual void visit(const TemplateNameId *name)
    {
        _item = newCompletionItem(name);
        _item.text = QLatin1String(name->identifier()->chars());
    }

    virtual void visit(const DestructorNameId *name)
    { _item = newCompletionItem(name); }

    virtual void visit(const OperatorNameId *name)
    { _item = newCompletionItem(name); }

    virtual void visit(const ConversionNameId *name)
    { _item = newCompletionItem(name); }

    virtual void visit(const QualifiedNameId *name)
    { _item = newCompletionItem(name->unqualifiedNameId()); }
};

struct CompleteFunctionDeclaration
{
    explicit CompleteFunctionDeclaration(Function *f = 0)
        : function(f)
    {}

    Function *function;
};

} // namespace Internal
} // namespace CppTools

using namespace CppTools::Internal;

Q_DECLARE_METATYPE(CompleteFunctionDeclaration)


FunctionArgumentWidget::FunctionArgumentWidget():
    m_startpos(-1),
    m_current(0),
    m_escapePressed(false)
{
    QObject *editorObject = Core::EditorManager::instance()->currentEditor();
    m_editor = qobject_cast<TextEditor::ITextEditor *>(editorObject);

    m_popupFrame = new Utils::FakeToolTip(m_editor->widget());

    QToolButton *downArrow = new QToolButton;
    downArrow->setArrowType(Qt::DownArrow);
    downArrow->setFixedSize(16, 16);
    downArrow->setAutoRaise(true);

    QToolButton *upArrow = new QToolButton;
    upArrow->setArrowType(Qt::UpArrow);
    upArrow->setFixedSize(16, 16);
    upArrow->setAutoRaise(true);

    setParent(m_popupFrame);
    setFocusPolicy(Qt::NoFocus);

    m_pager = new QWidget;
    QHBoxLayout *hbox = new QHBoxLayout(m_pager);
    hbox->setMargin(0);
    hbox->setSpacing(0);
    hbox->addWidget(upArrow);
    m_numberLabel = new QLabel;
    hbox->addWidget(m_numberLabel);
    hbox->addWidget(downArrow);

    QHBoxLayout *layout = new QHBoxLayout;
    layout->setMargin(0);
    layout->setSpacing(0);
    layout->addWidget(m_pager);
    layout->addWidget(this);
    m_popupFrame->setLayout(layout);

    connect(upArrow, SIGNAL(clicked()), SLOT(previousPage()));
    connect(downArrow, SIGNAL(clicked()), SLOT(nextPage()));

    setTextFormat(Qt::RichText);

    qApp->installEventFilter(this);
}

void FunctionArgumentWidget::showFunctionHint(QList<Function *> functionSymbols,
                                              const LookupContext &context,
                                              int startPosition)
{
    Q_ASSERT(!functionSymbols.isEmpty());

    if (m_startpos == startPosition)
        return;

    m_pager->setVisible(functionSymbols.size() > 1);

    m_items = functionSymbols;
    m_context = context;
    m_startpos = startPosition;
    m_current = 0;
    m_escapePressed = false;

    // update the text
    m_currentarg = -1;
    updateArgumentHighlight();

    m_popupFrame->show();
}

void FunctionArgumentWidget::nextPage()
{
    m_current = (m_current + 1) % m_items.size();
    updateHintText();
}

void FunctionArgumentWidget::previousPage()
{
    if (m_current == 0)
        m_current = m_items.size() - 1;
    else
        --m_current;

    updateHintText();
}

void FunctionArgumentWidget::updateArgumentHighlight()
{
    int curpos = m_editor->position();
    if (curpos < m_startpos) {
        m_popupFrame->close();
        return;
    }

    QString str = m_editor->textAt(m_startpos, curpos - m_startpos);
    int argnr = 0;
    int parcount = 0;
    SimpleLexer tokenize;
    QList<SimpleToken> tokens = tokenize(str);
    for (int i = 0; i < tokens.count(); ++i) {
        const SimpleToken &tk = tokens.at(i);
        if (tk.is(T_LPAREN))
            ++parcount;
        else if (tk.is(T_RPAREN))
            --parcount;
        else if (! parcount && tk.is(T_COMMA))
            ++argnr;
    }

    if (m_currentarg != argnr) {
        m_currentarg = argnr;
        updateHintText();
    }

    if (parcount < 0)
        m_popupFrame->close();
}

bool FunctionArgumentWidget::eventFilter(QObject *obj, QEvent *e)
{
    switch (e->type()) {
    case QEvent::ShortcutOverride:
        if (static_cast<QKeyEvent*>(e)->key() == Qt::Key_Escape) {
            m_escapePressed = true;
        }
        break;
    case QEvent::KeyPress:
        if (static_cast<QKeyEvent*>(e)->key() == Qt::Key_Escape) {
            m_escapePressed = true;
        }
        if (m_items.size() > 1) {
            QKeyEvent *ke = static_cast<QKeyEvent*>(e);
            if (ke->key() == Qt::Key_Up) {
                previousPage();
                return true;
            } else if (ke->key() == Qt::Key_Down) {
                nextPage();
                return true;
            }
            return false;
        }
        break;
    case QEvent::KeyRelease:
        if (static_cast<QKeyEvent*>(e)->key() == Qt::Key_Escape && m_escapePressed) {
            m_popupFrame->close();
            return false;
        }
        updateArgumentHighlight();
        break;
    case QEvent::WindowDeactivate:
    case QEvent::FocusOut:
        if (obj != m_editor->widget())
            break;
        m_popupFrame->close();
        break;
    case QEvent::MouseButtonPress:
    case QEvent::MouseButtonRelease:
    case QEvent::MouseButtonDblClick:
    case QEvent::Wheel: {
            QWidget *widget = qobject_cast<QWidget *>(obj);
            if (! (widget == this || m_popupFrame->isAncestorOf(widget))) {
                m_popupFrame->close();
            }
        }
        break;
    default:
        break;
    }
    return false;
}

void FunctionArgumentWidget::updateHintText()
{
    Overview overview;
    overview.setShowReturnTypes(true);
    overview.setShowArgumentNames(true);
    overview.setMarkedArgument(m_currentarg + 1);
    Function *f = currentFunction();

    const QString prettyMethod = overview(f->type(), f->name());
    const int begin = overview.markedArgumentBegin();
    const int end = overview.markedArgumentEnd();

    QString hintText;
    hintText += Qt::escape(prettyMethod.left(begin));
    hintText += "<b>";
    hintText += Qt::escape(prettyMethod.mid(begin, end - begin));
    hintText += "</b>";
    hintText += Qt::escape(prettyMethod.mid(end));
    setText(hintText);

    m_numberLabel->setText(tr("%1 of %2").arg(m_current + 1).arg(m_items.size()));

    m_popupFrame->setFixedWidth(m_popupFrame->minimumSizeHint().width());

    const QDesktopWidget *desktop = QApplication::desktop();
#ifdef Q_WS_MAC
    const QRect screen = desktop->availableGeometry(desktop->screenNumber(m_editor->widget()));
#else
    const QRect screen = desktop->screenGeometry(desktop->screenNumber(m_editor->widget()));
#endif

    const QSize sz = m_popupFrame->sizeHint();
    QPoint pos = m_editor->cursorRect(m_startpos).topLeft();
    pos.setY(pos.y() - sz.height() - 1);

    if (pos.x() + sz.width() > screen.right())
        pos.setX(screen.right() - sz.width());

    m_popupFrame->move(pos);
}

CppCodeCompletion::CppCodeCompletion(CppModelManager *manager)
    : ICompletionCollector(manager),
      m_manager(manager),
      m_editor(0),
      m_startPosition(-1),
      m_forcedCompletion(false),
      m_completionOperator(T_EOF_SYMBOL),
      m_objcEnabled(true)
{
}

QIcon CppCodeCompletion::iconForSymbol(Symbol *symbol) const
{
    return m_icons.iconForSymbol(symbol);
}

/*
  Searches backwards for an access operator.
*/
static int startOfOperator(TokenCache *tokenCache,
                           TextEditor::ITextEditable *editor,
                           int pos, unsigned *kind,
                           bool wantFunctionCall)
{
    const QChar ch  = pos > -1 ? editor->characterAt(pos - 1) : QChar();
    const QChar ch2 = pos >  0 ? editor->characterAt(pos - 2) : QChar();
    const QChar ch3 = pos >  1 ? editor->characterAt(pos - 3) : QChar();

    int start = pos;
    int completionKind = T_EOF_SYMBOL;

    switch (ch.toLatin1()) {
    case '.':
        if (ch2 != QLatin1Char('.')) {
            completionKind = T_DOT;
            --start;
        }
        break;
    case ',':
        completionKind = T_COMMA;
        --start;
        break;
    case '(':
        if (wantFunctionCall) {
            completionKind = T_LPAREN;
            --start;
        }
        break;
    case ':':
        if (ch3 != QLatin1Char(':') && ch2 == QLatin1Char(':')) {
            completionKind = T_COLON_COLON;
            start -= 2;
        }
        break;
    case '>':
        if (ch2 == QLatin1Char('-')) {
            completionKind = T_ARROW;
            start -= 2;
        }
        break;
    case '*':
        if (ch2 == QLatin1Char('.')) {
            completionKind = T_DOT_STAR;
            start -= 2;
        } else if (ch3 == QLatin1Char('-') && ch2 == QLatin1Char('>')) {
            completionKind = T_ARROW_STAR;
            start -= 3;
        }
        break;
    case '\\':
    case '@':
        if (ch2.isNull() || ch2.isSpace()) {
            completionKind = T_DOXY_COMMENT;
            --start;
        }
        break;
    case '<':
        completionKind = T_ANGLE_STRING_LITERAL;
        --start;
        break;
    case '"':
        completionKind = T_STRING_LITERAL;
        --start;
        break;
    case '/':
        completionKind = T_SLASH;
        --start;
        break;
    case '#':
        completionKind = T_POUND;
        --start;
        break;
    }

    if (start == pos)
        return start;

    TextEditor::BaseTextEditor *edit = qobject_cast<TextEditor::BaseTextEditor *>(editor->widget());
    QTextCursor tc(edit->textCursor());
    tc.setPosition(pos);

    // Include completion: make sure the quote character is the first one on the line
    if (completionKind == T_STRING_LITERAL) {
        QTextCursor s = tc;
        s.movePosition(QTextCursor::StartOfLine, QTextCursor::KeepAnchor);
        QString sel = s.selectedText();
        if (sel.indexOf(QLatin1Char('"')) < sel.length() - 1) {
            completionKind = T_EOF_SYMBOL;
            start = pos;
        }
    }

    if (completionKind == T_COMMA) {
        ExpressionUnderCursor expressionUnderCursor(tokenCache);
        if (expressionUnderCursor.startOfFunctionCall(tc) == -1) {
            completionKind = T_EOF_SYMBOL;
            start = pos;
        }
    }

    const SimpleToken tk = tokenCache->tokenUnderCursor(tc);

    if (completionKind == T_DOXY_COMMENT && !(tk.is(T_DOXY_COMMENT) || tk.is(T_CPP_DOXY_COMMENT))) {
        completionKind = T_EOF_SYMBOL;
        start = pos;
    }
    // Don't complete in comments or strings, but still check for include completion
    else if (tk.is(T_COMMENT) || tk.is(T_CPP_COMMENT) ||
             (tk.isLiteral() && (completionKind != T_STRING_LITERAL
                                 && completionKind != T_ANGLE_STRING_LITERAL
                                 && completionKind != T_SLASH))) {
        completionKind = T_EOF_SYMBOL;
        start = pos;
    }
    // Include completion: can be triggered by slash, but only in a string
    else if (completionKind == T_SLASH && (tk.isNot(T_STRING_LITERAL) && tk.isNot(T_ANGLE_STRING_LITERAL))) {
        completionKind = T_EOF_SYMBOL;
        start = pos;
    }
    else if (completionKind == T_LPAREN) {
        const QList<SimpleToken> &tokens = tokenCache->tokensForBlock(tc.block());
        int i = 0;
        for (; i < tokens.size(); ++i) {
            const SimpleToken &token = tokens.at(i);
            if (token.position() == tk.position()) {
                if (i == 0) // no token on the left, but might be on a previous line
                    break;
                const SimpleToken &previousToken = tokens.at(i - 1);
                if (previousToken.is(T_IDENTIFIER) || previousToken.is(T_GREATER)
                    || previousToken.is(T_SIGNAL) || previousToken.is(T_SLOT))
                    break;
            }
        }

        if (i == tokens.size()) {
            completionKind = T_EOF_SYMBOL;
            start = pos;
        }
    }
    // Check for include preprocessor directive
    else if (completionKind == T_STRING_LITERAL || completionKind == T_ANGLE_STRING_LITERAL || completionKind == T_SLASH) {
        bool include = false;
        const QList<SimpleToken> &tokens = tokenCache->tokensForBlock(tc.block());
        if (tokens.size() >= 3) {
            if (tokens.at(0).is(T_POUND) && tokens.at(1).is(T_IDENTIFIER) && (tokens.at(2).is(T_STRING_LITERAL) ||
                                                                              tokens.at(2).is(T_ANGLE_STRING_LITERAL))) {
                QString directive = tokenCache->text(tc.block(), 1);
                if (directive == QLatin1String("include") ||
                    directive == QLatin1String("include_next") ||
                    directive == QLatin1String("import")) {
                    include = true;
                }
            }
        }

        if (!include) {
            completionKind = T_EOF_SYMBOL;
            start = pos;
        }
    }

    if (kind)
        *kind = completionKind;

    return start;
}

bool CppCodeCompletion::supportsEditor(TextEditor::ITextEditable *editor)
{ return m_manager->isCppEditor(editor); }

TextEditor::ITextEditable *CppCodeCompletion::editor() const
{ return m_editor; }

int CppCodeCompletion::startPosition() const
{ return m_startPosition; }

bool CppCodeCompletion::triggersCompletion(TextEditor::ITextEditable *editor)
{
    const int pos = editor->position();
    TokenCache *tokenCache = m_manager->tokenCache(editor);
    unsigned token = T_EOF_SYMBOL;

    if (startOfOperator(tokenCache, editor, pos, &token, /*want function call=*/ true) != pos) {
        if (token == T_POUND) {
            if (TextEditor::BaseTextEditor *edit = qobject_cast<TextEditor::BaseTextEditor *>(editor->widget())) {
                QTextCursor tc(edit->document());
                tc.setPosition(pos);
                return tc.positionInBlock() == 1;
            }

            return false;
        }

        return true;
    }

    return false;
}

int CppCodeCompletion::startCompletion(TextEditor::ITextEditable *editor)
{
    int index = startCompletionHelper(editor);
    if (index != -1) {
        if (m_completionOperator != T_EOF_SYMBOL)
            qSort(m_completions.begin(), m_completions.end(), completionItemLessThan);

        // always remove duplicates
        m_completions = removeDuplicates(m_completions);
    }
    return index;
}

int CppCodeCompletion::startCompletionHelper(TextEditor::ITextEditable *editor)
{
    TextEditor::BaseTextEditor *edit = qobject_cast<TextEditor::BaseTextEditor *>(editor->widget());
    if (! edit)
        return -1;

    m_editor = editor;

    const int startOfName = findStartOfName();
    m_startPosition = startOfName;
    m_completionOperator = T_EOF_SYMBOL;

    int endOfOperator = m_startPosition;

    // Skip whitespace preceding this position
    while (editor->characterAt(endOfOperator - 1).isSpace())
        --endOfOperator;

    TokenCache *tokenCache = m_manager->tokenCache(editor);
    int endOfExpression = startOfOperator(tokenCache, editor, endOfOperator,
                                          &m_completionOperator,
                                          /*want function call =*/ true);

    Core::IFile *file = editor->file();
    QString fileName = file->fileName();

    int line = 0, column = 0;
    edit->convertPosition(editor->position(), &line, &column);
    // qDebug() << "line:" << line << "column:" << column;

    if (m_completionOperator == T_DOXY_COMMENT) {
        for (int i = 1; i < T_DOXY_LAST_TAG; ++i) {
            TextEditor::CompletionItem item(this);
            item.text.append(QString::fromLatin1(doxygenTagSpell(i)));
            item.icon = m_icons.keywordIcon();
            m_completions.append(item);
        }

        return m_startPosition;
    }

    // Pre-processor completion
    if (m_completionOperator == T_POUND) {
        completePreprocessor();
        m_startPosition = startOfName;
        return m_startPosition;
    }

    // Include completion
    if (m_completionOperator == T_STRING_LITERAL
        || m_completionOperator == T_ANGLE_STRING_LITERAL
        || m_completionOperator == T_SLASH) {

        QTextCursor c = edit->textCursor();
        c.setPosition(endOfExpression);
        if (completeInclude(c))
            m_startPosition = startOfName;
        return m_startPosition;
    }

    ExpressionUnderCursor expressionUnderCursor(m_manager->tokenCache(editor));
    QTextCursor tc(edit->document());

    if (m_completionOperator == T_COMMA) {
        tc.setPosition(endOfExpression);
        const int start = expressionUnderCursor.startOfFunctionCall(tc);
        if (start == -1) {
            m_completionOperator = T_EOF_SYMBOL;
            return -1;
        }

        endOfExpression = start;
        m_startPosition = start + 1;
        m_completionOperator = T_LPAREN;
    }

    QString expression;
    tc.setPosition(endOfExpression);

    if (m_completionOperator) {
        expression = expressionUnderCursor(tc);

        if (m_completionOperator == T_LPAREN) {
            if (expression.endsWith(QLatin1String("SIGNAL")))
                m_completionOperator = T_SIGNAL;

            else if (expression.endsWith(QLatin1String("SLOT")))
                m_completionOperator = T_SLOT;

            else if (editor->position() != endOfOperator) {
                // We don't want a function completion when the cursor isn't at the opening brace
                expression.clear();
                m_completionOperator = T_EOF_SYMBOL;
                m_startPosition = startOfName;
            }
        }
    }

    //qDebug() << "***** expression:" << expression;
    return startCompletionInternal(edit, fileName, line, column, expression, endOfExpression);
}

int CppCodeCompletion::startCompletionInternal(TextEditor::BaseTextEditor *edit,
                                               const QString fileName,
                                               unsigned line, unsigned column,
                                               const QString &expr,
                                               int endOfExpression)
{
    QString expression = expr.trimmed();
    const Snapshot snapshot = m_manager->snapshot();

    Document::Ptr thisDocument = snapshot.document(fileName);
    if (! thisDocument)
        return -1;

    typeOfExpression.init(thisDocument, snapshot);

    Scope *scope = thisDocument->scopeAt(line, column);
    Q_ASSERT(scope != 0);

    if (expression.isEmpty()) {
        if (m_completionOperator == T_EOF_SYMBOL || m_completionOperator == T_COLON_COLON) {
            (void) typeOfExpression(expression, scope);
            globalCompletion(scope);
            if (m_completions.isEmpty())
                return -1;
            return m_startPosition;
        }

        else if (m_completionOperator == T_SIGNAL || m_completionOperator == T_SLOT) {
            // Apply signal/slot completion on 'this'
            expression = QLatin1String("this");
        }
    }

    QList<LookupItem> results = typeOfExpression(expression, scope, TypeOfExpression::Preprocess);

    if (results.isEmpty()) {
        if (m_completionOperator == T_SIGNAL || m_completionOperator == T_SLOT) {
            if (! (expression.isEmpty() || expression == QLatin1String("this"))) {
                expression = QLatin1String("this");
                results = typeOfExpression(expression, scope);
            }

            if (results.isEmpty())
                return -1;

        } else if (m_completionOperator == T_LPAREN) {
            // Find the expression that precedes the current name
            int index = endOfExpression;
            while (m_editor->characterAt(index - 1).isSpace())
                --index;
            index = findStartOfName(index);

            QTextCursor tc(edit->document());
            tc.setPosition(index);

            TokenCache *tokenCache = m_manager->tokenCache(edit->editableInterface());
            ExpressionUnderCursor expressionUnderCursor(tokenCache);
            const QString baseExpression = expressionUnderCursor(tc);

            // Resolve the type of this expression
            const QList<LookupItem> results =
                    typeOfExpression(baseExpression, scope,
                                     TypeOfExpression::Preprocess);

            // If it's a class, add completions for the constructors
            foreach (const LookupItem &result, results) {
                if (result.type()->isClassType()) {
                    if (completeConstructorOrFunction(results, endOfExpression, true))
                        return m_startPosition;

                    break;
                }
            }
            return -1;

        } else {
            // nothing to do.
            return -1;

        }
    }

    switch (m_completionOperator) {
    case T_LPAREN:
        if (completeConstructorOrFunction(results, endOfExpression, false))
            return m_startPosition;
        break;

    case T_DOT:
    case T_ARROW:
        if (completeMember(results))
            return m_startPosition;
        break;

    case T_COLON_COLON:
        if (completeScope(results))
            return m_startPosition;
        break;

    case T_SIGNAL:
        if (completeSignal(results))
            return m_startPosition;
        break;

    case T_SLOT:
        if (completeSlot(results))
            return m_startPosition;
        break;

    default:
        break;
    } // end of switch

    // nothing to do.
    return -1;
}

void CppCodeCompletion::globalCompletion(Scope *currentScope)
{
    const LookupContext &context = typeOfExpression.context();

    if (m_completionOperator == T_COLON_COLON) {
        completeNamespace(context.globalNamespace());
        return;
    }

    QList<ClassOrNamespace *> usingBindings;
    ClassOrNamespace *currentBinding = 0;

    for (Scope *scope = currentScope; scope; scope = scope->enclosingScope()) {
        if (scope->isBlockScope()) {
            if (ClassOrNamespace *binding = context.lookupType(scope->owner())) {
                for (unsigned i = 0; i < scope->symbolCount(); ++i) {
                    Symbol *member = scope->symbolAt(i);
                    if (! member->name())
                        continue;
                    else if (UsingNamespaceDirective *u = member->asUsingNamespaceDirective()) {
                        if (ClassOrNamespace *b = binding->lookupType(u->name()))
                            usingBindings.append(b);
                    }
                }
            }
        } else if (scope->isFunctionScope() || scope->isClassScope() || scope->isNamespaceScope()) {
            currentBinding = context.lookupType(scope->owner());
            break;
        }
    }

    for (Scope *scope = currentScope; scope; scope = scope->enclosingScope()) {
        if (scope->isBlockScope()) {
            for (unsigned i = 0; i < scope->symbolCount(); ++i) {
                addCompletionItem(scope->symbolAt(i));
            }
        } else if (scope->isFunctionScope()) {
            Scope *arguments = scope->owner()->asFunction()->arguments();
            for (unsigned i = 0; i < arguments->symbolCount(); ++i) {
                addCompletionItem(arguments->symbolAt(i));
            }
            break;
        } else {
            break;
        }
    }

    for (; currentBinding; currentBinding = currentBinding->parent()) {
        const QList<Symbol *> symbols = currentBinding->symbols();

        if (! symbols.isEmpty()) {
            if (symbols.first()->isNamespace())
                completeNamespace(currentBinding);
            else
                completeClass(currentBinding);
        }
    }

    foreach (ClassOrNamespace *b, usingBindings)
        completeNamespace(b);

    addKeywords();
    addMacros(context.thisDocument()->fileName(), context.snapshot());
}

bool CppCodeCompletion::completeConstructorOrFunction(const QList<LookupItem> &results,
                                                      int endOfExpression, bool toolTipOnly)
{
    const LookupContext &context = typeOfExpression.context();
    QList<Function *> functions;

    foreach (const LookupItem &result, results) {
        FullySpecifiedType exprTy = result.type().simplified();

        if (Class *klass = exprTy->asClassType()) {
            const Name *className = klass->name();
            if (! className)
                continue; // nothing to do for anonymoous classes.

            for (unsigned i = 0; i < klass->memberCount(); ++i) {
                Symbol *member = klass->memberAt(i);
                const Name *memberName = member->name();

                if (! memberName)
                    continue; // skip anonymous member.

                else if (memberName->isQualifiedNameId())
                    continue; // skip

                if (Function *funTy = member->type()->asFunctionType()) {
                    if (memberName->isEqualTo(className)) {
                        // it's a ctor.
                        functions.append(funTy);
                    }
                }
            }

            break;
        }
    }

    if (functions.isEmpty()) {
        foreach (const LookupItem &result, results) {
            FullySpecifiedType ty = result.type().simplified();

            if (Function *fun = ty->asFunctionType()) {

                if (! fun->name())
                    continue;
                else if (! functions.isEmpty() && functions.first()->scope() != fun->scope())
                    continue; // skip fun, it's an hidden declaration.

                bool newOverload = true;

                foreach (Function *f, functions) {
                    if (fun->isEqualTo(f)) {
                        newOverload = false;
                        break;
                    }
                }

                if (newOverload)
                    functions.append(fun);
            }
        }
    }

    if (functions.isEmpty()) {
        const Name *functionCallOp = context.control()->operatorNameId(OperatorNameId::FunctionCallOp);

        foreach (const LookupItem &result, results) {
            FullySpecifiedType ty = result.type().simplified();
            Scope *scope = result.scope();

            if (NamedType *namedTy = ty->asNamedType()) {
                if (ClassOrNamespace *b = context.lookupType(namedTy->name(), scope)) {
                    foreach (Symbol *overload, b->lookup(functionCallOp)) {
                        FullySpecifiedType overloadTy = overload->type().simplified();

                        if (Function *funTy = overloadTy->asFunctionType())
                            functions.append(funTy);
                    }
                }
            }
        }
    }

    // There are two different kinds of completion we want to provide:
    // 1. If this is a function call, we want to pop up a tooltip that shows the user
    // the possible overloads with their argument types and names.
    // 2. If this is a function definition, we want to offer autocompletion of
    // the function signature.

    // check if function signature autocompletion is appropriate
    if (! functions.isEmpty() && ! toolTipOnly) {

        // function definitions will o