Fix incorrect line breaking in QtWebKit.

QTextBoundaryFinder was not consistent with ICU.
See also:
https://bugs.webkit.org/show_bug.cgi?id=31076

The previous definition of a line break was that the index
in the string after which the line break should occur.
Now it is the index of the boundary at which the break should
occur (hence one more).

Task-number: QT-3495
Reviewed-by: Simon Hausmann
Reviewed-by: Lars Knoll

2 files changed, 114 insertions, 9 deletions

diff --git a/src/corelib/tools/qtextboundaryfinder.cpp b/src/corelib/tools/qtextboundaryfinder.cpp
index 7c40e35..ca4d3c3 100644
--- a/src/corelib/tools/qtextboundaryfinder.cpp
+++ b/src/corelib/tools/qtextboundaryfinder.cpp
@@ -130,6 +130,11 @@ static void init(QTextBoundaryFinder::BoundaryType type, const QChar *chars, int
     Line break boundaries give possible places where a line break
     might happen and sentence boundaries will show the beginning and
     end of whole sentences.
+
+    The first position in a string is always a valid boundary and
+    refers to the position before the first character. The last
+    position at the length of the string is also valid and refers
+    to the position after the last character.
 */
 
 /*!
@@ -362,7 +367,8 @@ int QTextBoundaryFinder::toNextBoundary()
             ++pos;
         break;
     case Line:
-        while (pos < length && d->attributes[pos].lineBreakType < HB_Break)
+        Q_ASSERT(pos);
+        while (pos < length && d->attributes[pos-1].lineBreakType < HB_Break)
             ++pos;
         break;
     }
@@ -404,7 +410,7 @@ int QTextBoundaryFinder::toPreviousBoundary()
             --pos;
         break;
     case Line:
-        while (pos > 0 && d->attributes[pos].lineBreakType < HB_Break)
+        while (pos > 0 && d->attributes[pos-1].lineBreakType < HB_Break)
             --pos;
         break;
     }
@@ -429,7 +435,7 @@ bool QTextBoundaryFinder::isAtBoundary() const
     case Word:
         return d->attributes[pos].wordBoundary;
     case Line:
-        return d->attributes[pos].lineBreakType >= HB_Break;
+        return (pos > 0) ? d->attributes[pos-1].lineBreakType >= HB_Break : true;
     case Sentence:
         return d->attributes[pos].sentenceBoundary;
     }
diff --git a/tests/auto/qtextboundaryfinder/tst_qtextboundaryfinder.cpp b/tests/auto/qtextboundaryfinder/tst_qtextboundaryfinder.cpp
index c60af5e..a562fbe 100644
--- a/tests/auto/qtextboundaryfinder/tst_qtextboundaryfinder.cpp
+++ b/tests/auto/qtextboundaryfinder/tst_qtextboundaryfinder.cpp
@@ -71,6 +71,10 @@ private slots:
     void isAtWordStart();
     void fastConstructor();
     void isAtBoundaryLine();
+    void toNextBoundary_data();
+    void toNextBoundary();
+    void toPreviousBoundary_data();
+    void toPreviousBoundary();
 };
 
 tst_QTextBoundaryFinder::tst_QTextBoundaryFinder()
@@ -292,25 +296,120 @@ void tst_QTextBoundaryFinder::fastConstructor()
 
 void tst_QTextBoundaryFinder::isAtBoundaryLine()
 {
-    // idx          0       1       2       3       4       5
-    // break?       -       -       -       +       -       +
+    // idx       0       1       2       3       4       5      6
+    // break?    -       -       -       -       +       -      +
     QChar s[] = { 0x0061, 0x00AD, 0x0062, 0x0009, 0x0063, 0x0064 };
     QString text(s, sizeof(s)/sizeof(s[0]));
-    qDebug() << "text = " << text << ", length = " << text.length();
+//    qDebug() << "text = " << text << ", length = " << text.length();
     QTextBoundaryFinder finder(QTextBoundaryFinder::Line, text.constData(), text.length(), /*buffer*/0, /*buffer size*/0);
     finder.setPosition(0);
-    QVERIFY(!finder.isAtBoundary());
+    QVERIFY(finder.isAtBoundary());
     finder.setPosition(1);
     QVERIFY(!finder.isAtBoundary());
     finder.setPosition(2);
     QVERIFY(!finder.isAtBoundary());
     finder.setPosition(3);
-    QVERIFY(finder.isAtBoundary());
-    finder.setPosition(4);
     QVERIFY(!finder.isAtBoundary());
+    finder.setPosition(4);
+    QVERIFY(finder.isAtBoundary());
     finder.setPosition(5);
+    QVERIFY(!finder.isAtBoundary());
+    finder.setPosition(6);
     QVERIFY(finder.isAtBoundary());
 }
 
+Q_DECLARE_METATYPE(QList<int>)
+
+void tst_QTextBoundaryFinder::toNextBoundary_data()
+{
+    QTest::addColumn<QString>("text");
+    QTest::addColumn<int>("type");
+    QTest::addColumn< QList<int> >("boundaries");
+
+    QList<int> boundaries;
+    boundaries << 0 << 3 << 4 << 7 << 8 << 11 << 12 << 13 << 16 << 17 << 20 << 21 << 24 << 25;
+    QTest::newRow("Line") << QString("Aaa bbb ccc. Ddd eee fff.") << int(QTextBoundaryFinder::Word) \
+            << boundaries;
+
+    boundaries.clear();
+    boundaries << 0 << 13 << 25;
+    QTest::newRow("Line") << QString("Aaa bbb ccc. Ddd eee fff.") << int(QTextBoundaryFinder::Sentence) \
+            << boundaries;
+
+    boundaries.clear();
+    boundaries << 0 << 4 << 8 << 13 << 17 << 21 << 25;
+    QTest::newRow("Line") << QString("Aaa bbb ccc. Ddd eee fff.") << int(QTextBoundaryFinder::Line) \
+            << boundaries;
+
+    boundaries.clear();
+    boundaries << 0 << 5 << 9 << 15 << 17 << 21 << 28;
+    QTest::newRow("Line") << QString::fromUtf8("Diga-nos qualé a sua opinião") << int(QTextBoundaryFinder::Line)
+            << boundaries;
+
+}
+
+void tst_QTextBoundaryFinder::toNextBoundary()
+{
+    QFETCH(QString, text);
+    QFETCH(int, type);
+    QFETCH(QList<int>, boundaries);
+
+    QList<int> foundBoundaries;
+    QTextBoundaryFinder boundaryFinder(QTextBoundaryFinder::BoundaryType(type), text);
+    boundaryFinder.toStart();
+    for(int next = 0; next != -1; next = boundaryFinder.toNextBoundary())
+        foundBoundaries << next;
+    QCOMPARE(boundaries, foundBoundaries);
+}
+
+void tst_QTextBoundaryFinder::toPreviousBoundary_data()
+{
+    QTest::addColumn<QString>("text");
+    QTest::addColumn<int>("type");
+    QTest::addColumn< QList<int> >("boundaries");
+
+    QList<int> boundaries;
+    boundaries << 25 << 24 << 21 << 20 << 17 << 16 << 13 << 12 << 11 << 8 << 7 << 4 << 3 << 0;
+    QTest::newRow("Line") << QString("Aaa bbb ccc. Ddd eee fff.") << int(QTextBoundaryFinder::Word)
+            << boundaries;
+
+    boundaries.clear();
+    boundaries << 25 << 13 << 0;
+    QTest::newRow("Line") << QString("Aaa bbb ccc. Ddd eee fff.") << int(QTextBoundaryFinder::Sentence)
+            << boundaries;
+
+    boundaries.clear();
+    boundaries << 25 << 21 << 17 << 13 << 8 << 4 << 0;
+    QTest::newRow("Line") << QString("Aaa bbb ccc. Ddd eee fff.") << int(QTextBoundaryFinder::Line)
+            << boundaries;
+
+    boundaries.clear();
+    boundaries << 28 << 21 << 17 << 15 << 9 << 5 << 0;
+    QTest::newRow("Line") << QString::fromUtf8("Diga-nos qualé a sua opinião") << int(QTextBoundaryFinder::Line)
+            << boundaries;
+
+}
+
+void tst_QTextBoundaryFinder::toPreviousBoundary()
+{
+    QFETCH(QString, text);
+    QFETCH(int, type);
+    QFETCH(QList<int>, boundaries);
+
+    QList<int> foundBoundaries;
+    QTextBoundaryFinder boundaryFinder(QTextBoundaryFinder::BoundaryType(type), text);
+    boundaryFinder.toEnd();
+    for (int previous = boundaryFinder.position();
+         previous != -1;
+         previous = boundaryFinder.toPreviousBoundary())
+    {
+        foundBoundaries << previous;
+    }
+    QCOMPARE(boundaries, foundBoundaries);
+}
+
+
+
+
 QTEST_MAIN(tst_QTextBoundaryFinder)
 #include "tst_qtextboundaryfinder.moc"