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39
40#include "qsyntaxhighlighter.h"
41
42#ifndef QT_NO_SYNTAXHIGHLIGHTER
43#include <private/qobject_p.h>
44#include <qtextdocument.h>
45#include <private/qtextdocument_p.h>
46#include <qtextlayout.h>
47#include <qpointer.h>
48#include <qscopedvaluerollback.h>
49#include <qtextobject.h>
50#include <qtextcursor.h>
51#include <qdebug.h>
52#include <qtimer.h>
53
54#include <algorithm>
55
56QT_BEGIN_NAMESPACE
57
58class QSyntaxHighlighterPrivate : public QObjectPrivate
59{
60 Q_DECLARE_PUBLIC(QSyntaxHighlighter)
61public:
62 inline QSyntaxHighlighterPrivate()
63 : rehighlightPending(false), inReformatBlocks(false)
64 {}
65
66 QPointer<QTextDocument> doc;
67
68 void _q_reformatBlocks(int from, int charsRemoved, int charsAdded);
69 void reformatBlocks(int from, int charsRemoved, int charsAdded);
70 void reformatBlock(const QTextBlock &block);
71
72 inline void rehighlight(QTextCursor &cursor, QTextCursor::MoveOperation operation)
73 {
74 QScopedValueRollback<bool> bg(inReformatBlocks, true);
75 cursor.beginEditBlock();
76 int from = cursor.position();
77 cursor.movePosition(op: operation);
78 reformatBlocks(from, charsRemoved: 0, charsAdded: cursor.position() - from);
79 cursor.endEditBlock();
80 }
81
82 inline void _q_delayedRehighlight() {
83 if (!rehighlightPending)
84 return;
85 rehighlightPending = false;
86 q_func()->rehighlight();
87 }
88
89 void applyFormatChanges();
90 QVector<QTextCharFormat> formatChanges;
91 QTextBlock currentBlock;
92 bool rehighlightPending;
93 bool inReformatBlocks;
94};
95
96void QSyntaxHighlighterPrivate::applyFormatChanges()
97{
98 bool formatsChanged = false;
99
100 QTextLayout *layout = currentBlock.layout();
101
102 QVector<QTextLayout::FormatRange> ranges = layout->formats();
103
104 const int preeditAreaStart = layout->preeditAreaPosition();
105 const int preeditAreaLength = layout->preeditAreaText().length();
106
107 if (preeditAreaLength != 0) {
108 auto isOutsidePreeditArea = [=](const QTextLayout::FormatRange &range) {
109 return range.start < preeditAreaStart
110 || range.start + range.length > preeditAreaStart + preeditAreaLength;
111 };
112 const auto it = std::remove_if(first: ranges.begin(), last: ranges.end(),
113 pred: isOutsidePreeditArea);
114 if (it != ranges.end()) {
115 ranges.erase(begin: it, end: ranges.end());
116 formatsChanged = true;
117 }
118 } else if (!ranges.isEmpty()) {
119 ranges.clear();
120 formatsChanged = true;
121 }
122
123 int i = 0;
124 while (i < formatChanges.count()) {
125 QTextLayout::FormatRange r;
126
127 while (i < formatChanges.count() && formatChanges.at(i) == r.format)
128 ++i;
129
130 if (i == formatChanges.count())
131 break;
132
133 r.start = i;
134 r.format = formatChanges.at(i);
135
136 while (i < formatChanges.count() && formatChanges.at(i) == r.format)
137 ++i;
138
139 Q_ASSERT(i <= formatChanges.count());
140 r.length = i - r.start;
141
142 if (preeditAreaLength != 0) {
143 if (r.start >= preeditAreaStart)
144 r.start += preeditAreaLength;
145 else if (r.start + r.length >= preeditAreaStart)
146 r.length += preeditAreaLength;
147 }
148
149 ranges << r;
150 formatsChanged = true;
151 }
152
153 if (formatsChanged) {
154 layout->setFormats(ranges);
155 doc->markContentsDirty(from: currentBlock.position(), length: currentBlock.length());
156 }
157}
158
159void QSyntaxHighlighterPrivate::_q_reformatBlocks(int from, int charsRemoved, int charsAdded)
160{
161 if (!inReformatBlocks && !rehighlightPending)
162 reformatBlocks(from, charsRemoved, charsAdded);
163}
164
165void QSyntaxHighlighterPrivate::reformatBlocks(int from, int charsRemoved, int charsAdded)
166{
167 QTextBlock block = doc->findBlock(pos: from);
168 if (!block.isValid())
169 return;
170
171 int endPosition;
172 QTextBlock lastBlock = doc->findBlock(pos: from + charsAdded + (charsRemoved > 0 ? 1 : 0));
173 if (lastBlock.isValid())
174 endPosition = lastBlock.position() + lastBlock.length();
175 else
176 endPosition = doc->docHandle()->length();
177
178 bool forceHighlightOfNextBlock = false;
179
180 while (block.isValid() && (block.position() < endPosition || forceHighlightOfNextBlock)) {
181 const int stateBeforeHighlight = block.userState();
182
183 reformatBlock(block);
184
185 forceHighlightOfNextBlock = (block.userState() != stateBeforeHighlight);
186
187 block = block.next();
188 }
189
190 formatChanges.clear();
191}
192
193void QSyntaxHighlighterPrivate::reformatBlock(const QTextBlock &block)
194{
195 Q_Q(QSyntaxHighlighter);
196
197 Q_ASSERT_X(!currentBlock.isValid(), "QSyntaxHighlighter::reformatBlock()", "reFormatBlock() called recursively");
198
199 currentBlock = block;
200
201 formatChanges.fill(t: QTextCharFormat(), size: block.length() - 1);
202 q->highlightBlock(text: block.text());
203 applyFormatChanges();
204
205 currentBlock = QTextBlock();
206}
207
208/*!
209 \class QSyntaxHighlighter
210 \reentrant
211 \inmodule QtGui
212
213 \brief The QSyntaxHighlighter class allows you to define syntax
214 highlighting rules, and in addition you can use the class to query
215 a document's current formatting or user data.
216
217 \since 4.1
218
219 \ingroup richtext-processing
220
221 The QSyntaxHighlighter class is a base class for implementing
222 QTextDocument syntax highlighters. A syntax highligher automatically
223 highlights parts of the text in a QTextDocument. Syntax highlighters are
224 often used when the user is entering text in a specific format (for example source code)
225 and help the user to read the text and identify syntax errors.
226
227 To provide your own syntax highlighting, you must subclass
228 QSyntaxHighlighter and reimplement highlightBlock().
229
230 When you create an instance of your QSyntaxHighlighter subclass,
231 pass it the QTextDocument that you want the syntax
232 highlighting to be applied to. For example:
233
234 \snippet code/src_gui_text_qsyntaxhighlighter.cpp 0
235
236 After this your highlightBlock() function will be called
237 automatically whenever necessary. Use your highlightBlock()
238 function to apply formatting (e.g. setting the font and color) to
239 the text that is passed to it. QSyntaxHighlighter provides the
240 setFormat() function which applies a given QTextCharFormat on
241 the current text block. For example:
242
243 \snippet code/src_gui_text_qsyntaxhighlighter.cpp 1
244
245 \target QSyntaxHighlighter multiblock
246
247 Some syntaxes can have constructs that span several text
248 blocks. For example, a C++ syntax highlighter should be able to
249 cope with \c{/}\c{*...*}\c{/} multiline comments. To deal with
250 these cases it is necessary to know the end state of the previous
251 text block (e.g. "in comment").
252
253 Inside your highlightBlock() implementation you can query the end
254 state of the previous text block using the previousBlockState()
255 function. After parsing the block you can save the last state
256 using setCurrentBlockState().
257
258 The currentBlockState() and previousBlockState() functions return
259 an int value. If no state is set, the returned value is -1. You
260 can designate any other value to identify any given state using
261 the setCurrentBlockState() function. Once the state is set the
262 QTextBlock keeps that value until it is set set again or until the
263 corresponding paragraph of text is deleted.
264
265 For example, if you're writing a simple C++ syntax highlighter,
266 you might designate 1 to signify "in comment":
267
268 \snippet code/src_gui_text_qsyntaxhighlighter.cpp 2
269
270 In the example above, we first set the current block state to
271 0. Then, if the previous block ended within a comment, we highlight
272 from the beginning of the current block (\c {startIndex =
273 0}). Otherwise, we search for the given start expression. If the
274 specified end expression cannot be found in the text block, we
275 change the current block state by calling setCurrentBlockState(),
276 and make sure that the rest of the block is highlighted.
277
278 In addition you can query the current formatting and user data
279 using the format() and currentBlockUserData() functions
280 respectively. You can also attach user data to the current text
281 block using the setCurrentBlockUserData() function.
282 QTextBlockUserData can be used to store custom settings. In the
283 case of syntax highlighting, it is in particular interesting as
284 cache storage for information that you may figure out while
285 parsing the paragraph's text. For an example, see the
286 setCurrentBlockUserData() documentation.
287
288 \sa QTextDocument, {Syntax Highlighter Example}
289*/
290
291/*!
292 Constructs a QSyntaxHighlighter with the given \a parent.
293
294 If the parent is a QTextEdit, it installs the syntax highlighter on the
295 parents document. The specified QTextEdit also becomes the owner of
296 the QSyntaxHighlighter.
297*/
298QSyntaxHighlighter::QSyntaxHighlighter(QObject *parent)
299 : QObject(*new QSyntaxHighlighterPrivate, parent)
300{
301 if (parent && parent->inherits(classname: "QTextEdit")) {
302 QTextDocument *doc = qvariant_cast<QTextDocument *>(v: parent->property(name: "document"));
303 if (doc)
304 setDocument(doc);
305 }
306}
307
308/*!
309 Constructs a QSyntaxHighlighter and installs it on \a parent.
310 The specified QTextDocument also becomes the owner of the
311 QSyntaxHighlighter.
312*/
313QSyntaxHighlighter::QSyntaxHighlighter(QTextDocument *parent)
314 : QObject(*new QSyntaxHighlighterPrivate, parent)
315{
316 setDocument(parent);
317}
318
319/*!
320 Destructor. Uninstalls this syntax highlighter from the text document.
321*/
322QSyntaxHighlighter::~QSyntaxHighlighter()
323{
324 setDocument(nullptr);
325}
326
327/*!
328 Installs the syntax highlighter on the given QTextDocument \a doc.
329 A QSyntaxHighlighter can only be used with one document at a time.
330*/
331void QSyntaxHighlighter::setDocument(QTextDocument *doc)
332{
333 Q_D(QSyntaxHighlighter);
334 if (d->doc) {
335 disconnect(sender: d->doc, SIGNAL(contentsChange(int,int,int)),
336 receiver: this, SLOT(_q_reformatBlocks(int,int,int)));
337
338 QTextCursor cursor(d->doc);
339 cursor.beginEditBlock();
340 for (QTextBlock blk = d->doc->begin(); blk.isValid(); blk = blk.next())
341 blk.layout()->clearFormats();
342 cursor.endEditBlock();
343 }
344 d->doc = doc;
345 if (d->doc) {
346 connect(sender: d->doc, SIGNAL(contentsChange(int,int,int)),
347 receiver: this, SLOT(_q_reformatBlocks(int,int,int)));
348 if (!d->doc->isEmpty()) {
349 d->rehighlightPending = true;
350 QTimer::singleShot(msec: 0, receiver: this, SLOT(_q_delayedRehighlight()));
351 }
352 }
353}
354
355/*!
356 Returns the QTextDocument on which this syntax highlighter is
357 installed.
358*/
359QTextDocument *QSyntaxHighlighter::document() const
360{
361 Q_D(const QSyntaxHighlighter);
362 return d->doc;
363}
364
365/*!
366 \since 4.2
367
368 Reapplies the highlighting to the whole document.
369
370 \sa rehighlightBlock()
371*/
372void QSyntaxHighlighter::rehighlight()
373{
374 Q_D(QSyntaxHighlighter);
375 if (!d->doc)
376 return;
377
378 QTextCursor cursor(d->doc);
379 d->rehighlight(cursor, operation: QTextCursor::End);
380 d->rehighlightPending = false; // user manually did a full rehighlight
381}
382
383/*!
384 \since 4.6
385
386 Reapplies the highlighting to the given QTextBlock \a block.
387
388 \sa rehighlight()
389*/
390void QSyntaxHighlighter::rehighlightBlock(const QTextBlock &block)
391{
392 Q_D(QSyntaxHighlighter);
393 if (!d->doc || !block.isValid() || block.document() != d->doc)
394 return;
395
396 const bool rehighlightPending = d->rehighlightPending;
397
398 QTextCursor cursor(block);
399 d->rehighlight(cursor, operation: QTextCursor::EndOfBlock);
400
401 if (rehighlightPending)
402 d->rehighlightPending = rehighlightPending;
403}
404
405/*!
406 \fn void QSyntaxHighlighter::highlightBlock(const QString &text)
407
408 Highlights the given text block. This function is called when
409 necessary by the rich text engine, i.e. on text blocks which have
410 changed.
411
412 To provide your own syntax highlighting, you must subclass
413 QSyntaxHighlighter and reimplement highlightBlock(). In your
414 reimplementation you should parse the block's \a text and call
415 setFormat() as often as necessary to apply any font and color
416 changes that you require. For example:
417
418 \snippet code/src_gui_text_qsyntaxhighlighter.cpp 1
419
420 See the \l{QSyntaxHighlighter multiblock}{Detailed Description} for
421 examples of using setCurrentBlockState(), currentBlockState()
422 and previousBlockState() to handle syntaxes with constructs that
423 span several text blocks
424
425 \sa previousBlockState(), setFormat(), setCurrentBlockState()
426*/
427
428/*!
429 This function is applied to the syntax highlighter's current text
430 block (i.e. the text that is passed to the highlightBlock()
431 function).
432
433 The specified \a format is applied to the text from the \a start
434 position for a length of \a count characters (if \a count is 0,
435 nothing is done). The formatting properties set in \a format are
436 merged at display time with the formatting information stored
437 directly in the document, for example as previously set with
438 QTextCursor's functions. Note that the document itself remains
439 unmodified by the format set through this function.
440
441 \sa format(), highlightBlock()
442*/
443void QSyntaxHighlighter::setFormat(int start, int count, const QTextCharFormat &format)
444{
445 Q_D(QSyntaxHighlighter);
446 if (start < 0 || start >= d->formatChanges.count())
447 return;
448
449 const int end = qMin(a: start + count, b: d->formatChanges.count());
450 for (int i = start; i < end; ++i)
451 d->formatChanges[i] = format;
452}
453
454/*!
455 \overload
456
457 The specified \a color is applied to the current text block from
458 the \a start position for a length of \a count characters.
459
460 The other attributes of the current text block, e.g. the font and
461 background color, are reset to default values.
462
463 \sa format(), highlightBlock()
464*/
465void QSyntaxHighlighter::setFormat(int start, int count, const QColor &color)
466{
467 QTextCharFormat format;
468 format.setForeground(color);
469 setFormat(start, count, format);
470}
471
472/*!
473 \overload
474
475 The specified \a font is applied to the current text block from
476 the \a start position for a length of \a count characters.
477
478 The other attributes of the current text block, e.g. the font and
479 background color, are reset to default values.
480
481 \sa format(), highlightBlock()
482*/
483void QSyntaxHighlighter::setFormat(int start, int count, const QFont &font)
484{
485 QTextCharFormat format;
486 format.setFont(font);
487 setFormat(start, count, format);
488}
489
490/*!
491 \fn QTextCharFormat QSyntaxHighlighter::format(int position) const
492
493 Returns the format at \a position inside the syntax highlighter's
494 current text block.
495*/
496QTextCharFormat QSyntaxHighlighter::format(int pos) const
497{
498 Q_D(const QSyntaxHighlighter);
499 if (pos < 0 || pos >= d->formatChanges.count())
500 return QTextCharFormat();
501 return d->formatChanges.at(i: pos);
502}
503
504/*!
505 Returns the end state of the text block previous to the
506 syntax highlighter's current block. If no value was
507 previously set, the returned value is -1.
508
509 \sa highlightBlock(), setCurrentBlockState()
510*/
511int QSyntaxHighlighter::previousBlockState() const
512{
513 Q_D(const QSyntaxHighlighter);
514 if (!d->currentBlock.isValid())
515 return -1;
516
517 const QTextBlock previous = d->currentBlock.previous();
518 if (!previous.isValid())
519 return -1;
520
521 return previous.userState();
522}
523
524/*!
525 Returns the state of the current text block. If no value is set,
526 the returned value is -1.
527*/
528int QSyntaxHighlighter::currentBlockState() const
529{
530 Q_D(const QSyntaxHighlighter);
531 if (!d->currentBlock.isValid())
532 return -1;
533
534 return d->currentBlock.userState();
535}
536
537/*!
538 Sets the state of the current text block to \a newState.
539
540 \sa highlightBlock()
541*/
542void QSyntaxHighlighter::setCurrentBlockState(int newState)
543{
544 Q_D(QSyntaxHighlighter);
545 if (!d->currentBlock.isValid())
546 return;
547
548 d->currentBlock.setUserState(newState);
549}
550
551/*!
552 Attaches the given \a data to the current text block. The
553 ownership is passed to the underlying text document, i.e. the
554 provided QTextBlockUserData object will be deleted if the
555 corresponding text block gets deleted.
556
557 QTextBlockUserData can be used to store custom settings. In the
558 case of syntax highlighting, it is in particular interesting as
559 cache storage for information that you may figure out while
560 parsing the paragraph's text.
561
562 For example while parsing the text, you can keep track of
563 parenthesis characters that you encounter ('{[(' and the like),
564 and store their relative position and the actual QChar in a simple
565 class derived from QTextBlockUserData:
566
567 \snippet code/src_gui_text_qsyntaxhighlighter.cpp 3
568
569 During cursor navigation in the associated editor, you can ask the
570 current QTextBlock (retrieved using the QTextCursor::block()
571 function) if it has a user data object set and cast it to your \c
572 BlockData object. Then you can check if the current cursor
573 position matches with a previously recorded parenthesis position,
574 and, depending on the type of parenthesis (opening or closing),
575 find the next opening or closing parenthesis on the same level.
576
577 In this way you can do a visual parenthesis matching and highlight
578 from the current cursor position to the matching parenthesis. That
579 makes it easier to spot a missing parenthesis in your code and to
580 find where a corresponding opening/closing parenthesis is when
581 editing parenthesis intensive code.
582
583 \sa QTextBlock::setUserData()
584*/
585void QSyntaxHighlighter::setCurrentBlockUserData(QTextBlockUserData *data)
586{
587 Q_D(QSyntaxHighlighter);
588 if (!d->currentBlock.isValid())
589 return;
590
591 d->currentBlock.setUserData(data);
592}
593
594/*!
595 Returns the QTextBlockUserData object previously attached to the
596 current text block.
597
598 \sa QTextBlock::userData(), setCurrentBlockUserData()
599*/
600QTextBlockUserData *QSyntaxHighlighter::currentBlockUserData() const
601{
602 Q_D(const QSyntaxHighlighter);
603 if (!d->currentBlock.isValid())
604 return nullptr;
605
606 return d->currentBlock.userData();
607}
608
609/*!
610 \since 4.4
611
612 Returns the current text block.
613*/
614QTextBlock QSyntaxHighlighter::currentBlock() const
615{
616 Q_D(const QSyntaxHighlighter);
617 return d->currentBlock;
618}
619
620QT_END_NAMESPACE
621
622#include "moc_qsyntaxhighlighter.cpp"
623
624#endif // QT_NO_SYNTAXHIGHLIGHTER
625

source code of qtbase/src/gui/text/qsyntaxhighlighter.cpp