qt-creator/src/plugins/clangcodemodel/clangassistproposalitem.cpp

/****************************************************************************
**
** Copyright (C) 2015 The Qt Company Ltd.
** Contact: http://www.qt.io/licensing
**
** This file is part of Qt Creator.
**
** Commercial License Usage
** Licensees holding valid commercial Qt licenses may use this file in
** accordance with the commercial license agreement provided with the
** Software or, alternatively, in accordance with the terms contained in
** a written agreement between you and The Qt Company.  For licensing terms and
** conditions see http://www.qt.io/terms-conditions.  For further information
** use the contact form at http://www.qt.io/contact-us.
**
** 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 or version 3 as published by the Free
** Software Foundation and appearing in the file LICENSE.LGPLv21 and
** LICENSE.LGPLv3 included in the packaging of this file.  Please review the
** following information to ensure the GNU Lesser General Public License
** requirements will be met: https://www.gnu.org/licenses/lgpl.html and
** http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
**
** In addition, as a special exception, The Qt Company gives you certain additional
** rights.  These rights are described in The Qt Company LGPL Exception
** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
**
****************************************************************************/

#include "clangassistproposalitem.h"

#include "clangcompletionchunkstotextconverter.h"

#include <cplusplus/MatchingText.h>
#include <cplusplus/Token.h>

#include <texteditor/completionsettings.h>
#include <texteditor/textdocument.h>
#include <texteditor/texteditor.h>
#include <texteditor/texteditorsettings.h>

using namespace CPlusPlus;
using namespace ClangBackEnd;

namespace ClangCodeModel {
namespace Internal {

bool ClangAssistProposalItem::prematurelyApplies(const QChar &typedChar) const
{
    bool applies = false;

    if (m_completionOperator == T_SIGNAL || m_completionOperator == T_SLOT)
        applies = QString::fromLatin1("(,").contains(typedChar);
    else if (m_completionOperator == T_STRING_LITERAL || m_completionOperator == T_ANGLE_STRING_LITERAL)
        applies = (typedChar == QLatin1Char('/')) && text().endsWith(QLatin1Char('/'));
    else if (codeCompletion().completionKind() == CodeCompletion::ObjCMessageCompletionKind)
        applies = QString::fromLatin1(";.,").contains(typedChar);
    else
        applies = QString::fromLatin1(";.,:(").contains(typedChar);

    if (applies)
        m_typedChar = typedChar;

    return applies;
}

static bool hasOnlyBlanksBeforeCursorInLine(QTextCursor textCursor)
{
    textCursor.movePosition(QTextCursor::StartOfLine, QTextCursor::KeepAnchor);

    const auto textBeforeCursor = textCursor.selectedText();

    const auto nonSpace = std::find_if(textBeforeCursor.cbegin(),
                                       textBeforeCursor.cend(),
                                       [] (const QChar &signBeforeCursor) {
        return !signBeforeCursor.isSpace();
    });

    return nonSpace == textBeforeCursor.cend();
}

void ClangAssistProposalItem::applyContextualContent(TextEditor::TextEditorWidget *editorWidget,
                                                     int basePosition) const
{
    const CodeCompletion ccr = codeCompletion();

    QString textToBeInserted = text();
    QString extraChars;
    int extraLength = 0;
    int cursorOffset = 0;

    bool autoParenthesesEnabled = true;
    if (m_completionOperator == T_SIGNAL || m_completionOperator == T_SLOT) {
        extraChars += QLatin1Char(')');
        if (m_typedChar == QLatin1Char('(')) // Eat the opening parenthesis
            m_typedChar = QChar();
    } else if (m_completionOperator == T_STRING_LITERAL || m_completionOperator == T_ANGLE_STRING_LITERAL) {
        if (!textToBeInserted.endsWith(QLatin1Char('/'))) {
            extraChars += QLatin1Char((m_completionOperator == T_ANGLE_STRING_LITERAL) ? '>' : '"');
        } else {
            if (m_typedChar == QLatin1Char('/')) // Eat the slash
                m_typedChar = QChar();
        }
    } else if (ccr.completionKind() == CodeCompletion::KeywordCompletionKind) {
        CompletionChunksToTextConverter converter;
        converter.setupForKeywords();

        converter.parseChunks(ccr.chunks());

        textToBeInserted = converter.text();
        if (converter.hasPlaceholderPositions())
            cursorOffset = converter.placeholderPositions().at(0) - converter.text().size();
    } else if (!ccr.text().isEmpty()) {
        const TextEditor::CompletionSettings &completionSettings =
                TextEditor::TextEditorSettings::instance()->completionSettings();
        const bool autoInsertBrackets = completionSettings.m_autoInsertBrackets;

        if (autoInsertBrackets &&
                (ccr.completionKind() == CodeCompletion::FunctionCompletionKind
                 || ccr.completionKind() == CodeCompletion::DestructorCompletionKind
                 || ccr.completionKind() == CodeCompletion::SignalCompletionKind
                 || ccr.completionKind() == CodeCompletion::SlotCompletionKind)) {
            // When the user typed the opening parenthesis, he'll likely also type the closing one,
            // in which case it would be annoying if we put the cursor after the already automatically
            // inserted closing parenthesis.
            const bool skipClosingParenthesis = m_typedChar != QLatin1Char('(');

            if (completionSettings.m_spaceAfterFunctionName)
                extraChars += QLatin1Char(' ');
            extraChars += QLatin1Char('(');
            if (m_typedChar == QLatin1Char('('))
                m_typedChar = QChar();

            // If the function doesn't return anything, automatically place the semicolon,
            // unless we're doing a scope completion (then it might be function definition).
            const QChar characterAtCursor = editorWidget->characterAt(editorWidget->position());
            bool endWithSemicolon = m_typedChar == QLatin1Char(';')/*
                                            || (function->returnType()->isVoidType() && m_completionOperator != T_COLON_COLON)*/; //###
            const QChar semicolon = m_typedChar.isNull() ? QLatin1Char(';') : m_typedChar;

            if (endWithSemicolon && characterAtCursor == semicolon) {
                endWithSemicolon = false;
                m_typedChar = QChar();
            }

            // If the function takes no arguments, automatically place the closing parenthesis
            if (!isOverloaded() && !ccr.hasParameters() && skipClosingParenthesis) {
                extraChars += QLatin1Char(')');
                if (endWithSemicolon) {
                    extraChars += semicolon;
                    m_typedChar = QChar();
                }
            } else if (autoParenthesesEnabled) {
                const QChar lookAhead = editorWidget->characterAt(editorWidget->position() + 1);
                if (MatchingText::shouldInsertMatchingText(lookAhead)) {
                    extraChars += QLatin1Char(')');
                    --cursorOffset;
                    if (endWithSemicolon) {
                        extraChars += semicolon;
                        --cursorOffset;
                        m_typedChar = QChar();
                    }
                }
            }
        }

#if 0
        if (autoInsertBrackets && data().canConvert<CompleteFunctionDeclaration>()) {
            if (m_typedChar == QLatin1Char('('))
                m_typedChar = QChar();

            // everything from the closing parenthesis on are extra chars, to
            // make sure an auto-inserted ")" gets replaced by ") const" if necessary
            int closingParen = toInsert.lastIndexOf(QLatin1Char(')'));
            extraChars = toInsert.mid(closingParen);
            toInsert.truncate(closingParen);
        }
#endif
    }

    // Append an unhandled typed character, adjusting cursor offset when it had been adjusted before
    if (!m_typedChar.isNull()) {
        extraChars += m_typedChar;
        if (cursorOffset != 0)
            --cursorOffset;
    }

    // Avoid inserting characters that are already there
    const int endsPosition = editorWidget->position(TextEditor::EndOfLinePosition);
    const QString existingText = editorWidget->textAt(editorWidget->position(), endsPosition - editorWidget->position());
    int existLength = 0;
    if (!existingText.isEmpty() && ccr.completionKind() != CodeCompletion::KeywordCompletionKind) {
        // Calculate the exist length in front of the extra chars
        existLength = textToBeInserted.length() - (editorWidget->position() - basePosition);
        while (!existingText.startsWith(textToBeInserted.right(existLength))) {
            if (--existLength == 0)
                break;
        }
    }
    for (int i = 0; i < extraChars.length(); ++i) {
        const QChar a = extraChars.at(i);
        const QChar b = editorWidget->characterAt(editorWidget->position() + i + existLength);
        if (a == b)
            ++extraLength;
        else
            break;
    }

    textToBeInserted += extraChars;

    // Insert the remainder of the name
    const int length = editorWidget->position() - basePosition + existLength + extraLength;
    const auto textToBeReplaced = editorWidget->textAt(basePosition, length);

    if (textToBeReplaced != textToBeInserted) {
        editorWidget->setCursorPosition(basePosition);
        editorWidget->replace(length, textToBeInserted);
        if (cursorOffset)
            editorWidget->setCursorPosition(editorWidget->position() + cursorOffset);

        // indent the statement
        if (ccr.completionKind() == CodeCompletion::KeywordCompletionKind) {
            auto selectionCursor = editorWidget->textCursor();
            selectionCursor.setPosition(basePosition);
            selectionCursor.setPosition(basePosition + textToBeInserted.size(), QTextCursor::KeepAnchor);

            auto basePositionCursor = editorWidget->textCursor();
            basePositionCursor.setPosition(basePosition);
            if (hasOnlyBlanksBeforeCursorInLine(basePositionCursor))
                editorWidget->textDocument()->autoIndent(selectionCursor);
        }
    }
}

void ClangAssistProposalItem::keepCompletionOperator(unsigned compOp)
{
    m_completionOperator = compOp;
}

bool ClangAssistProposalItem::isOverloaded() const
{
    return !m_overloads.isEmpty();
}

void ClangAssistProposalItem::addOverload(const CodeCompletion &ccr)
{
    m_overloads.append(ccr);
}

void ClangAssistProposalItem::setCodeCompletion(const CodeCompletion &codeCompletion)
{
    m_codeCompletion = codeCompletion;
}

const ClangBackEnd::CodeCompletion &ClangAssistProposalItem::codeCompletion() const
{
    return m_codeCompletion;
}

} // namespace Internal
} // namespace ClangCodeModel