texteditwithclangcodecompletion.cpp

#include "texteditwithclangcodecompletion.h"

#include <QCompleter>
#include <QAbstractItemView>
#include <QKeyEvent>
#include <QScrollBar>
#include <QStringListModel>
#include <QMessageBox>
#include <QDebug>

#define TextEditWithClangCodeCompletion_DUMMY_FILENAME "dummyfile.cpp"

TextEditWithClangCodeCompletion::TextEditWithClangCodeCompletion(QWidget *parent)
    : QTextEdit(parent)
    , m_CompleterPopup(new QCompleter(this))
{
    setText(tr("//Start typing some C/C++, Ctrl+Space activates code completion\n\n//Demo:\ntypedef int CodeCompleteMe0\ntypedef int CodeCompleteMe1;\nCodeCo\n//          ^Click here and press Ctrl+Space"));
    m_CompleterPopup->setCaseSensitivity(Qt::CaseInsensitive);
    m_CompleterPopup->setWidget(this);
    m_CompleterPopup->setCompletionMode(QCompleter::PopupCompletion);
    connect(m_CompleterPopup, SIGNAL(activated(QString)), this, SLOT(insertCompletion(QString)));

    m_ClangIndex = clang_createIndex(1, 0);
    if(!m_ClangIndex)
    {
        QMessageBox::critical(this, tr("Error"), tr("clang_createIndex failed"));
        close();
    }

    resize(500, 300);
    setWindowTitle(tr("Text Edit with Clang Code Completion"));
}
void TextEditWithClangCodeCompletion::keyPressEvent(QKeyEvent *e)
{
    if(m_CompleterPopup->popup()->isVisible())
    {
        switch (e->key())
        {
        case Qt::Key_Enter:
        case Qt::Key_Return:
        case Qt::Key_Escape:
        case Qt::Key_Tab:
        case Qt::Key_Backtab:
            e->ignore();
            return;
        default:
            break;
        }
    }

    bool isShortcut = ((e->modifiers() & Qt::ControlModifier) && e->key() == Qt::Key_Space);
    if(!isShortcut)
        QTextEdit::keyPressEvent(e);

    static QString endOfWordCharacters("~!@#$%^&*()_+{}|:\"<>?,./;'[]\\-=");
    bool hasModifier = (e->modifiers() != Qt::NoModifier);

    QTextCursor tc = textCursor();
    tc.select(QTextCursor::WordUnderCursor);
    QString completionPrefix = tc.selectedText();

    if(!isShortcut && (hasModifier || e->text().isEmpty() || completionPrefix.length() < 3 || endOfWordCharacters.contains(e->text().right(1))))
    {
        m_CompleterPopup->popup()->hide();
        return;
    }

    populateCompleterPopupViaClangCodeComplete(completionPrefix);

    if(completionPrefix != m_CompleterPopup->completionPrefix())
    {
        m_CompleterPopup->setCompletionPrefix(completionPrefix);
        m_CompleterPopup->popup()->setCurrentIndex(m_CompleterPopup->completionModel()->index(0, 0));
    }
    QRect cr = cursorRect();
    cr.setWidth(m_CompleterPopup->popup()->sizeHintForColumn(0) + m_CompleterPopup->popup()->verticalScrollBar()->sizeHint().width());
    m_CompleterPopup->complete(cr);
}
void TextEditWithClangCodeCompletion::focusInEvent(QFocusEvent *e)
{
    m_CompleterPopup->setWidget(this);
    QTextEdit::focusInEvent(e);
}
void TextEditWithClangCodeCompletion::populateCompleterPopupViaClangCodeComplete(const QString &token)
{
    CXUnsavedFile unsavedFiles[1];
    unsavedFiles[0].Filename = TextEditWithClangCodeCompletion_DUMMY_FILENAME;
    QString docString = document()->toPlainText();
    std::string docStdString = docString.toStdString();
    unsavedFiles[0].Contents = docStdString.c_str();
    unsavedFiles[0].Length = docStdString.length();

    CXTranslationUnit translationUnit = clang_parseTranslationUnit(m_ClangIndex, TextEditWithClangCodeCompletion_DUMMY_FILENAME, 0, 0, unsavedFiles, 1, CXTranslationUnit_PrecompiledPreamble);
    if(!translationUnit)
    {
        QMessageBox::critical(this, tr("Error"), tr("parseTranslationUnit failed"));
        m_CompleterPopup->setModel(new QStringListModel(m_CompleterPopup));
        return;
    }

    //clang_reparseTranslationUnit(u, 0, 0, 0);

    int line = textCursor().blockNumber()+1;
    qDebug() << "Line: " << line;
    int column = (textCursor().positionInBlock()+1)-token.length(); //columNumber instead?
    qDebug() << "Column: " << column;

    CXCodeCompleteResults* codeCompleteResults = clang_codeCompleteAt(translationUnit, TextEditWithClangCodeCompletion_DUMMY_FILENAME, line, column, unsavedFiles, 1, 0);
    if(!codeCompleteResults)
    {
        QMessageBox::critical(this, tr("Error"), tr("Could not complete"));
        m_CompleterPopup->setModel(new QStringListModel(m_CompleterPopup));
        return;
    }

    QStringList codeCompletionEntries;
    for(unsigned i = 0; i < codeCompleteResults->NumResults; ++i)
    {
        const CXCompletionString& str = codeCompleteResults->Results[i].CompletionString;
        for(unsigned j = 0; j < clang_getNumCompletionChunks(str); ++j)
        {
            if(clang_getCompletionChunkKind(str, j) != CXCompletionChunk_TypedText)
                continue;

            const CXString& out = clang_getCompletionChunkText(str, j);
            const char* codeCompletionEntry = clang_getCString(out);
            QString codeCompletionEntryQString = QString::fromLatin1(codeCompletionEntry, strlen(codeCompletionEntry));
            if(!codeCompletionEntryQString.trimmed().isEmpty())
                codeCompletionEntries.append(codeCompletionEntry);
        }
    }

    m_CompleterPopup->setModel(new QStringListModel(codeCompletionEntries, m_CompleterPopup));
    clang_disposeCodeCompleteResults(codeCompleteResults);
}
void TextEditWithClangCodeCompletion::insertCompletion(const QString &completion)
{
    if(m_CompleterPopup->widget() != this)
        return;
    QTextCursor tc = textCursor();
    tc.select(QTextCursor::WordUnderCursor);
    tc.removeSelectedText(); //capitalization may have been wrong, since we're doing case insensitive completing
    tc.insertText(completion);
    setTextCursor(tc);
}