Add QRegularExpression support to QTextDocument

Currently QTextDocuement only provides find using QRegExp. This patch
aims to add support for QRegularExpression.

[ChangeLog][QtGui][QTextDocument] Support for searching with a
QRegularExpression in a document has been added.

Change-Id: I6dba10545b83995d093407038a821fe54db3d261
Reviewed-by: Simon Hausmann <simon.hausmann@digia.com>

2 files changed, 131 insertions, 1 deletions

diff --git a/src/gui/text/qtextdocument.cpp b/src/gui/text/qtextdocument.cpp
index fa54776b6d..438fa75492 100644
--- a/src/gui/text/qtextdocument.cpp
+++ b/src/gui/text/qtextdocument.cpp
@@ -48,6 +48,7 @@
 #include "qtextlist.h"
 #include <qdebug.h>
 #include <qregexp.h>
+#include <qregularexpression.h>
 #include <qvarlengtharray.h>
 #include <qtextcodec.h>
 #include <qthread.h>
@@ -1432,6 +1433,131 @@ QTextCursor QTextDocument::find(const QRegExp &expr, const QTextCursor &from, Fi
     return find(expr, pos, options);
 }
 
+#ifndef QT_NO_REGULAREXPRESSION
+static bool findInBlock(const QTextBlock &block, const QRegularExpression &expression, int offset,
+                        QTextDocument::FindFlags options, QTextCursor *cursor)
+{
+    QRegularExpression expr(expression);
+    if (!(options & QTextDocument::FindCaseSensitively))
+        expr.setPatternOptions(expr.patternOptions() | QRegularExpression::CaseInsensitiveOption);
+    else
+        expr.setPatternOptions(expr.patternOptions() & ~QRegularExpression::CaseInsensitiveOption);
+
+    QString text = block.text();
+    text.replace(QChar::Nbsp, QLatin1Char(' '));
+    QRegularExpressionMatch match;
+    int idx = -1;
+
+    while (offset >= 0 && offset <= text.length()) {
+        idx = (options & QTextDocument::FindBackward) ?
+               text.lastIndexOf(expr, offset, &match) : text.indexOf(expr, offset, &match);
+        if (idx == -1)
+            return false;
+
+        if (options & QTextDocument::FindWholeWords) {
+            const int start = idx;
+            const int end = start + match.capturedLength();
+            if ((start != 0 && text.at(start - 1).isLetterOrNumber())
+                || (end != text.length() && text.at(end).isLetterOrNumber())) {
+                //if this is not a whole word, continue the search in the string
+                offset = (options & QTextDocument::FindBackward) ? idx-1 : end+1;
+                idx = -1;
+                continue;
+            }
+        }
+        //we have a hit, return the cursor for that.
+        break;
+    }
+    if (idx == -1)
+        return false;
+    *cursor = qMove(QTextCursor(block.docHandle(), block.position() + idx));
+    cursor->setPosition(cursor->position() + match.capturedLength(), QTextCursor::KeepAnchor);
+    return true;
+}
+
+/*!
+    \since 5.5
+
+    Finds the next occurrence, matching the regular expression, \a expr, in the document.
+    The search starts at the given \a from position, and proceeds forwards
+    through the document unless specified otherwise in the search options.
+    The \a options control the type of search performed.
+
+    Returns a cursor with the match selected if a match was found; otherwise
+    returns a null cursor.
+
+    If the \a from position is 0 (the default) the search begins from the beginning
+    of the document; otherwise it begins at the specified position.
+*/
+QTextCursor QTextDocument::find(const QRegularExpression &expr, int from, FindFlags options) const
+{
+    Q_D(const QTextDocument);
+
+    if (!expr.isValid())
+        return QTextCursor();
+
+    int pos = from;
+    //the cursor is positioned between characters, so for a backward search
+    //do not include the character given in the position.
+    if (options & FindBackward) {
+        --pos ;
+        if (pos < 0)
+            return QTextCursor();
+    }
+
+    QTextCursor cursor;
+    QTextBlock block = d->blocksFind(pos);
+
+    if (!(options & FindBackward)) {
+        int blockOffset = qMax(0, pos - block.position());
+        while (block.isValid()) {
+            if (findInBlock(block, expr, blockOffset, options, &cursor))
+                return cursor;
+            blockOffset = 0;
+            block = block.next();
+        }
+    } else {
+        int blockOffset = pos - block.position();
+        while (block.isValid()) {
+            if (findInBlock(block, expr, blockOffset, options, &cursor))
+                return cursor;
+            block = block.previous();
+            blockOffset = block.length() - 1;
+        }
+    }
+
+    return QTextCursor();
+}
+
+/*!
+    \since 5.5
+
+    Finds the next occurrence, matching the regular expression, \a expr, in the document.
+    The search starts at the position of the given \a from cursor, and proceeds
+    forwards through the document unless specified otherwise in the search
+    options. The \a options control the type of search performed.
+
+    Returns a cursor with the match selected if a match was found; otherwise
+    returns a null cursor.
+
+    If the given \a from cursor has a selection, the search begins after the
+    selection; otherwise it begins at the cursor's position.
+
+    By default the search is case-sensitive, and can match text anywhere in the
+    document.
+*/
+QTextCursor QTextDocument::find(const QRegularExpression &expr, const QTextCursor &from, FindFlags options) const
+{
+    int pos = 0;
+    if (!from.isNull()) {
+        if (options & QTextDocument::FindBackward)
+            pos = from.selectionStart();
+        else
+            pos = from.selectionEnd();
+    }
+    return find(expr, pos, options);
+}
+#endif // QT_NO_REGULAREXPRESSION
 
 /*!
     \fn QTextObject *QTextDocument::createObject(const QTextFormat &format)
diff --git a/src/gui/text/qtextdocument.h b/src/gui/text/qtextdocument.h
index 854cb29ed9..3f4b8b565b 100644
--- a/src/gui/text/qtextdocument.h
+++ b/src/gui/text/qtextdocument.h
@@ -169,10 +169,14 @@ public:
 
     QTextCursor find(const QString &subString, int from = 0, FindFlags options = 0) const;
     QTextCursor find(const QString &subString, const QTextCursor &from, FindFlags options = 0) const;
-
     QTextCursor find(const QRegExp &expr, int from = 0, FindFlags options = 0) const;
     QTextCursor find(const QRegExp &expr, const QTextCursor &from, FindFlags options = 0) const;
 
+#ifndef QT_NO_REGULAREXPRESSION
+    QTextCursor find(const QRegularExpression &expr, int from = 0, FindFlags options = 0) const;
+    QTextCursor find(const QRegularExpression &expr, const QTextCursor &from, FindFlags options = 0) const;
+#endif
+
     QTextFrame *frameAt(int pos) const;
     QTextFrame *rootFrame() const;