/**************************************************************************** ** ** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies). ** All rights reserved. ** Contact: Nokia Corporation (qt-info@nokia.com) ** ** This file is part of the QtGui module of the Qt Toolkit. ** ** $QT_BEGIN_LICENSE:LGPL$ ** No Commercial Usage ** This file contains pre-release code and may not be distributed. ** You may use this file in accordance with the terms and conditions ** contained in the Technology Preview License Agreement accompanying ** this package. ** ** 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. ** ** In addition, as a special exception, Nokia gives you certain additional ** rights. These rights are described in the Nokia Qt LGPL Exception ** version 1.1, included in the file LGPL_EXCEPTION.txt in this package. ** ** If you have questions regarding the use of this file, please contact ** Nokia at qt-info@nokia.com. ** ** ** ** ** ** ** ** ** $QT_END_LICENSE$ ** ****************************************************************************/ #include "qsyntaxhighlighter.h" #ifndef QT_NO_SYNTAXHIGHLIGHTER #include #include #include #include #include #include #include #include #include #include QT_BEGIN_NAMESPACE class QSyntaxHighlighterPrivate : public QObjectPrivate { Q_DECLARE_PUBLIC(QSyntaxHighlighter) public: inline QSyntaxHighlighterPrivate() : rehighlightPending(false) {} QPointer doc; void _q_reformatBlocks(int from, int charsRemoved, int charsAdded); void reformatBlock(QTextBlock block); inline void _q_delayedRehighlight() { if (!rehighlightPending) return; rehighlightPending = false; q_func()->rehighlight(); return; } void applyFormatChanges(); QVector formatChanges; QTextBlock currentBlock; bool rehighlightPending; }; void QSyntaxHighlighterPrivate::applyFormatChanges() { QTextLayout *layout = currentBlock.layout(); QList ranges = layout->additionalFormats(); const int preeditAreaStart = layout->preeditAreaPosition(); const int preeditAreaLength = layout->preeditAreaText().length(); QList::Iterator it = ranges.begin(); while (it != ranges.end()) { if (it->start >= preeditAreaStart && it->start + it->length <= preeditAreaStart + preeditAreaLength) ++it; else it = ranges.erase(it); } QTextCharFormat emptyFormat; QTextLayout::FormatRange r; r.start = r.length = -1; int i = 0; while (i < formatChanges.count()) { while (i < formatChanges.count() && formatChanges.at(i) == emptyFormat) ++i; if (i >= formatChanges.count()) break; r.start = i; r.format = formatChanges.at(i); while (i < formatChanges.count() && formatChanges.at(i) == r.format) ++i; if (i >= formatChanges.count()) break; r.length = i - r.start; if (r.start >= preeditAreaStart) { r.start += preeditAreaLength; } else if (r.start + r.length >= preeditAreaStart) { r.length += preeditAreaLength; } ranges << r; r.start = r.length = -1; } if (r.start != -1) { r.length = formatChanges.count() - r.start; if (r.start >= preeditAreaStart) { r.start += preeditAreaLength; } else if (r.start + r.length >= preeditAreaStart) { r.length += preeditAreaLength; } ranges << r; } layout->setAdditionalFormats(ranges); } void QSyntaxHighlighterPrivate::_q_reformatBlocks(int from, int charsRemoved, int charsAdded) { Q_UNUSED(charsRemoved); rehighlightPending = false; QTextBlock block = doc->findBlock(from); if (!block.isValid()) return; int endPosition; QTextBlock lastBlock = doc->findBlock(from + charsAdded); if (lastBlock.isValid()) endPosition = lastBlock.position() + lastBlock.length(); else endPosition = doc->docHandle()->length(); bool forceHighlightOfNextBlock = false; while (block.isValid() && (block.position() < endPosition || forceHighlightOfNextBlock)) { const int stateBeforeHighlight = block.userState(); reformatBlock(block); forceHighlightOfNextBlock = (block.userState() != stateBeforeHighlight); block = block.next(); } formatChanges.clear(); } void QSyntaxHighlighterPrivate::reformatBlock(QTextBlock block) { Q_Q(QSyntaxHighlighter); Q_ASSERT_X(!currentBlock.isValid(), "QSyntaxHighlighter::reformatBlock()", "reFormatBlock() called recursively"); currentBlock = block; QTextBlock previous = block.previous(); formatChanges.fill(QTextCharFormat(), block.length() - 1); q->highlightBlock(block.text()); applyFormatChanges(); doc->markContentsDirty(block.position(), block.length()); currentBlock = QTextBlock(); } /*! \class QSyntaxHighlighter \reentrant \brief The QSyntaxHighlighter class allows you to define syntax highlighting rules, and in addition you can use the class to query a document's current formatting or user data. \since 4.1 \ingroup text The QSyntaxHighlighter class is a base class for implementing QTextEdit syntax highlighters. A syntax highligher automatically highlights parts of the text in a QTextEdit, or more generally in a QTextDocument. Syntax highlighters are often used when the user is entering text in a specific format (for example source code) and help the user to read the text and identify syntax errors. To provide your own syntax highlighting, you must subclass QSyntaxHighlighter and reimplement highlightBlock(). When you create an instance of your QSyntaxHighlighter subclass, pass it the QTextEdit or QTextDocument that you want the syntax highlighting to be applied to. For example: \snippet doc/src/snippets/code/src_gui_text_qsyntaxhighlighter.cpp 0 After this your highlightBlock() function will be called automatically whenever necessary. Use your highlightBlock() function to apply formatting (e.g. setting the font and color) to the text that is passed to it. QSyntaxHighlighter provides the setFormat() function which applies a given QTextCharFormat on the current text block. For example: \snippet doc/src/snippets/code/src_gui_text_qsyntaxhighlighter.cpp 1 Some syntaxes can have constructs that span several text blocks. For example, a C++ syntax highlighter should be able to cope with \c{/}\c{*...*}\c{/} multiline comments. To deal with these cases it is necessary to know the end state of the previous text block (e.g. "in comment"). Inside your highlightBlock() implementation you can query the end state of the previous text block using the previousBlockState() function. After parsing the block you can save the last state using setCurrentBlockState(). The currentBlockState() and previousBlockState() functions return an int value. If no state is set, the returned value is -1. You can designate any other value to identify any given state using the setCurrentBlockState() function. Once the state is set the QTextBlock keeps that value until it is set set again or until the corresponding paragraph of text is deleted. For example, if you're writing a simple C++ syntax highlighter, you might designate 1 to signify "in comment": \snippet doc/src/snippets/code/src_gui_text_qsyntaxhighlighter.cpp 2 In the example above, we first set the current block state to 0. Then, if the previous block ended within a comment, we higlight from the beginning of the current block (\c {startIndex = 0}). Otherwise, we search for the given start expression. If the specified end expression cannot be found in the text block, we change the current block state by calling setCurrentBlockState(), and make sure that the rest of the block is higlighted. In addition you can query the current formatting and user data using the format() and currentBlockUserData() functions respectively. You can also attach user data to the current text block using the setCurrentBlockUserData() function. QTextBlockUserData can be used to store custom settings. In the case of syntax highlighting, it is in particular interesting as cache storage for information that you may figure out while parsing the paragraph's text. For an example, see the setCurrentBlockUserData() documentation. \sa QTextEdit, {Syntax Highlighter Example} */ /*! Constructs a QSyntaxHighlighter with the given \a parent. */ QSyntaxHighlighter::QSyntaxHighlighter(QObject *parent) : QObject(*new QSyntaxHighlighterPrivate, parent) { } /*! Constructs a QSyntaxHighlighter and installs it on \a parent. The specified QTextDocument also becomes the owner of the QSyntaxHighlighter. */ QSyntaxHighlighter::QSyntaxHighlighter(QTextDocument *parent) : QObject(*new QSyntaxHighlighterPrivate, parent) { setDocument(parent); } /*! Constructs a QSyntaxHighlighter and installs it on \a parent 's QTextDocument. The specified QTextEdit also becomes the owner of the QSyntaxHighlighter. */ QSyntaxHighlighter::QSyntaxHighlighter(QTextEdit *parent) : QObject(*new QSyntaxHighlighterPrivate, parent) { setDocument(parent->document()); } /*! Destructor. Uninstalls this syntax highlighter from the text document. */ QSyntaxHighlighter::~QSyntaxHighlighter() { setDocument(0); } /*! Installs the syntax highlighter on the given QTextDocument \a doc. A QSyntaxHighlighter can only be used with one document at a time. */ void QSyntaxHighlighter::setDocument(QTextDocument *doc) { Q_D(QSyntaxHighlighter); if (d->doc) { disconnect(d->doc, SIGNAL(contentsChange(int,int,int)), this, SLOT(_q_reformatBlocks(int,int,int))); QTextCursor cursor(d->doc); cursor.beginEditBlock(); for (QTextBlock blk = d->doc->begin(); blk.isValid(); blk = blk.next()) blk.layout()->clearAdditionalFormats(); cursor.endEditBlock(); } d->doc = doc; if (d->doc) { connect(d->doc, SIGNAL(contentsChange(int,int,int)), this, SLOT(_q_reformatBlocks(int,int,int))); QTimer::singleShot(0, this, SLOT(_q_delayedRehighlight())); d->rehighlightPending = true; } } /*! Returns the QTextDocument on which this syntax highlighter is installed. */ QTextDocument *QSyntaxHighlighter::document() const { Q_D(const QSyntaxHighlighter); return d->doc; } /*! \since 4.2 Redoes the highlighting of the whole document. */ void QSyntaxHighlighter::rehighlight() { Q_D(QSyntaxHighlighter); if (!d->doc) return; disconnect(d->doc, SIGNAL(contentsChange(int,int,int)), this, SLOT(_q_reformatBlocks(int,int,int))); QTextCursor cursor(d->doc); cursor.beginEditBlock(); cursor.movePosition(QTextCursor::End); d->_q_reformatBlocks(0, 0, cursor.position()); cursor.endEditBlock(); connect(d->doc, SIGNAL(contentsChange(int,int,int)), this, SLOT(_q_reformatBlocks(int,int,int))); } /*! \fn void QSyntaxHighlighter::highlightBlock(const QString &text) Highlights the given text block. This function is called when necessary by the rich text engine, i.e. on text blocks which have changed. To provide your own syntax highlighting, you must subclass QSyntaxHighlighter and reimplement highlightBlock(). In your reimplementation you should parse the block's \a text and call setFormat() as often as necessary to apply any font and color changes that you require. For example: \snippet doc/src/snippets/code/src_gui_text_qsyntaxhighlighter.cpp 3 Some syntaxes can have constructs that span several text blocks. For example, a C++ syntax highlighter should be able to cope with \c{/}\c{*...*}\c{/} multiline comments. To deal with these cases it is necessary to know the end state of the previous text block (e.g. "in comment"). Inside your highlightBlock() implementation you can query the end state of the previous text block using the previousBlockState() function. After parsing the block you can save the last state using setCurrentBlockState(). The currentBlockState() and previousBlockState() functions return an int value. If no state is set, the returned value is -1. You can designate any other value to identify any given state using the setCurrentBlockState() function. Once the state is set the QTextBlock keeps that value until it is set set again or until the corresponding paragraph of text gets deleted. For example, if you're writing a simple C++ syntax highlighter, you might designate 1 to signify "in comment". For a text block that ended in the middle of a comment you'd set 1 using setCurrentBlockState, and for other paragraphs you'd set 0. In your parsing code if the return value of previousBlockState() is 1, you would highlight the text as a C++ comment until you reached the closing \c{*}\c{/}. \sa previousBlockState(), setFormat(), setCurrentBlockState() */ /*! This function is applied to the syntax highlighter's current text block (i.e. the text that is passed to the highlightBlock() function). The specified \a format is applied to the text from the \a start position for a length of \a count characters (if \a count is 0, nothing is done). The formatting properties set in \a format are merged at display time with the formatting information stored directly in the document, for example as previously set with QTextCursor's functions. Note that the document itself remains unmodified by the format set through this function. \sa format(), highlightBlock() */ void QSyntaxHighlighter::setFormat(int start, int count, const QTextCharFormat &format) { Q_D(QSyntaxHighlighter); if (start < 0 || start >= d->formatChanges.count()) return; const int end = qMin(start + count, d->formatChanges.count()); for (int i = start; i < end; ++i) d->formatChanges[i] = format; } /*! \overload The specified \a color is applied to the current text block from the \a start position for a length of \a count characters. The other attributes of the current text block, e.g. the font and background color, are reset to default values. \sa format(), highlightBlock() */ void QSyntaxHighlighter::setFormat(int start, int count, const QColor &color) { QTextCharFormat format; format.setForeground(color); setFormat(start, count, format); } /*! \overload The specified \a font is applied to the current text block from the \a start position for a length of \a count characters. The other attributes of the current text block, e.g. the font and background color, are reset to default values. \sa format(), highlightBlock() */ void QSyntaxHighlighter::setFormat(int start, int count, const QFont &font) { QTextCharFormat format; format.setFont(font); setFormat(start, count, format); } /*! \fn QTextCharFormat QSyntaxHighlighter::format(int position) const Returns the format at \a position inside the syntax highlighter's current text block. */ QTextCharFormat QSyntaxHighlighter::format(int pos) const { Q_D(const QSyntaxHighlighter); if (pos < 0 || pos >= d->formatChanges.count()) return QTextCharFormat(); return d->formatChanges.at(pos); } /*! Returns the end state of the text block previous to the syntax highlighter's current block. If no value was previously set, the returned value is -1. \sa highlightBlock(), setCurrentBlockState() */ int QSyntaxHighlighter::previousBlockState() const { Q_D(const QSyntaxHighlighter); if (!d->currentBlock.isValid()) return -1; const QTextBlock previous = d->currentBlock.previous(); if (!previous.isValid()) return -1; return previous.userState(); } /*! Returns the state of the current text block. If no value is set, the returned value is -1. */ int QSyntaxHighlighter::currentBlockState() const { Q_D(const QSyntaxHighlighter); if (!d->currentBlock.isValid()) return -1; return d->currentBlock.userState(); } /*! Sets the state of the current text block to \a newState. \sa highlightBlock() */ void QSyntaxHighlighter::setCurrentBlockState(int newState) { Q_D(QSyntaxHighlighter); if (!d->currentBlock.isValid()) return; d->currentBlock.setUserState(newState); } /*! Attaches the given \a data to the current text block. The ownership is passed to the underlying text document, i.e. the provided QTextBlockUserData object will be deleted if the corresponding text block gets deleted. QTextBlockUserData can be used to store custom settings. In the case of syntax highlighting, it is in particular interesting as cache storage for information that you may figure out while parsing the paragraph's text. For example while parsing the text, you can keep track of parenthesis characters that you encounter ('{[(' and the like), and store their relative position and the actual QChar in a simple class derived from QTextBlockUserData: \snippet doc/src/snippets/code/src_gui_text_qsyntaxhighlighter.cpp 4 During cursor navigation in the associated editor, you can ask the current QTextBlock (retrieved using the QTextCursor::block() function) if it has a user data object set and cast it to your \c BlockData object. Then you can check if the current cursor position matches with a previously recorded parenthesis position, and, depending on the type of parenthesis (opening or closing), find the next opening or closing parenthesis on the same level. In this way you can do a visual parenthesis matching and highlight from the current cursor position to the matching parenthesis. That makes it easier to spot a missing parenthesis in your code and to find where a corresponding opening/closing parenthesis is when editing parenthesis intensive code. \sa QTextBlock::setUserData() */ void QSyntaxHighlighter::setCurrentBlockUserData(QTextBlockUserData *data) { Q_D(QSyntaxHighlighter); if (!d->currentBlock.isValid()) return; d->currentBlock.setUserData(data); } /*! Returns the QTextBlockUserData object previously attached to the current text block. \sa QTextBlock::userData(), setCurrentBlockUserData() */ QTextBlockUserData *QSyntaxHighlighter::currentBlockUserData() const { Q_D(const QSyntaxHighlighter); if (!d->currentBlock.isValid()) return 0; return d->currentBlock.userData(); } /*! \since 4.4 Returns the current text block. */ QTextBlock QSyntaxHighlighter::currentBlock() const { Q_D(const QSyntaxHighlighter); return d->currentBlock; } QT_END_NAMESPACE #include "moc_qsyntaxhighlighter.cpp" #endif // QT_NO_SYNTAXHIGHLIGHTER