Move QTextEngine implementation details from QTextLayout

As of now, we'll have everything related to the additional formats handling
just in a single place. Make specialData private to prevent accessing it
from outside. This helped in tracking-down several related issues:
- in format(const QScriptItem *), the resolvedFormatIndices can not be empty
  at that point, so the code path is dead;
- in resolveAdditionalFormats(), testing if formats has not been indexed yet
  is not needed since they are indexed just in the setter;
- in useRawFont mode, hasFormats() didn't check if QTextEngine really
  has some formats, which potentially leads to formatting artifacts.

Change-Id: Id4b912888fd5a1fa83f01007170134b6386e2879
Reviewed-by: Lars Knoll <lars.knoll@digia.com>
Reviewed-by: Eskil Abrahamsen Blomfeldt <eskil.abrahamsen-blomfeldt@digia.com>

3 files changed, 95 insertions, 86 deletions

diff --git a/src/gui/text/qtextengine.cpp b/src/gui/text/qtextengine.cpp
index f1a0804e68..ad85fedcd0 100644
--- a/src/gui/text/qtextengine.cpp
+++ b/src/gui/text/qtextengine.cpp
@@ -1164,7 +1164,7 @@ void QTextEngine::shapeTextWithHarfbuzz(int item) const
     layoutData->used += si.num_glyphs;
 }
 
-static void init(QTextEngine *e)
+void QTextEngine::init(QTextEngine *e)
 {
     e->ignoreBidi = false;
     e->cacheGlyphs = false;
@@ -1433,10 +1433,11 @@ void QTextEngine::itemize() const
 #ifndef QT_NO_RAWFONT
         if (useRawFont && specialData) {
             int lastIndex = 0;
+            const QTextFormatCollection *collection = formats();
             for (int i = 0; i < specialData->addFormats.size(); ++i) {
                 const QTextLayout::FormatRange &range = specialData->addFormats.at(i);
-                QTextCharFormat format = formats()->charFormat(specialData->addFormatIndices.at(i));
-                if (format.fontCapitalization()) {
+                const QTextCharFormat format = collection->charFormat(specialData->addFormatIndices.at(i));
+                if (format.hasProperty(QTextFormat::FontCapitalization)) {
                     itemizer.generate(lastIndex, range.start - lastIndex, QFont::MixedCase);
                     itemizer.generate(range.start, range.length, format.fontCapitalization());
                     lastIndex = range.start + range.length;
@@ -2209,25 +2210,9 @@ int QTextEngine::formatIndex(const QScriptItem *si) const
 
 QTextCharFormat QTextEngine::format(const QScriptItem *si) const
 {
-    QTextCharFormat format;
-    const QTextFormatCollection *formats = this->formats();
-
-    if (formats)
-        format = formats->charFormat(formatIndex(si));
-
-    if (specialData && specialData->resolvedFormatIndices.isEmpty()) {
-        int end = si->position + length(si);
-        for (int i = 0; i < specialData->addFormats.size(); ++i) {
-            const QTextLayout::FormatRange &r = specialData->addFormats.at(i);
-            if (r.start <= si->position && r.start + r.length >= end) {
-                if (!specialData->addFormatIndices.isEmpty())
-                    format.merge(formats->format(specialData->addFormatIndices.at(i)));
-                else
-                    format.merge(r.format);
-            }
-        }
-    }
-    return format;
+    if (const QTextFormatCollection *formats = this->formats())
+        return formats->charFormat(formatIndex(si));
+    return QTextCharFormat();
 }
 
 void QTextEngine::addRequiredBoundaries() const
@@ -2298,6 +2283,67 @@ bool QTextEngine::atSpace(int position) const
     return false;
 }
 
+void QTextEngine::setPreeditArea(int position, const QString &preeditText)
+{
+    if (preeditText.isEmpty()) {
+        if (!specialData)
+            return;
+        if (specialData->addFormats.isEmpty()) {
+            delete specialData;
+            specialData = 0;
+        } else {
+            specialData->preeditText = QString();
+            specialData->preeditPosition = -1;
+        }
+    } else {
+        if (!specialData)
+            specialData = new SpecialData;
+        specialData->preeditPosition = position;
+        specialData->preeditText = preeditText;
+    }
+    invalidate();
+    clearLineData();
+}
+
+QList<QTextLayout::FormatRange> QTextEngine::additionalFormats() const
+{
+    QList<QTextLayout::FormatRange> formatList;
+    if (!specialData)
+        return formatList;
+
+    formatList = specialData->addFormats;
+    if (!specialData->addFormatIndices.isEmpty()) {
+        const QTextFormatCollection *formats = this->formats();
+        Q_ASSERT(formats);
+        for (int i = 0; i < specialData->addFormatIndices.size(); ++i)
+            formatList[i].format = formats->charFormat(specialData->addFormatIndices.at(i));
+    }
+
+    return formatList;
+}
+
+void QTextEngine::setAdditionalFormats(const QList<QTextLayout::FormatRange> &formatList)
+{
+    if (formatList.isEmpty()) {
+        if (!specialData)
+            return;
+        if (specialData->preeditText.isEmpty()) {
+            delete specialData;
+            specialData = 0;
+        } else {
+            specialData->addFormats.clear();
+            specialData->addFormatIndices.clear();
+        }
+    } else {
+        if (!specialData) {
+            specialData = new SpecialData;
+            specialData->preeditPosition = -1;
+        }
+        specialData->addFormats = formatList;
+        indexAdditionalFormats();
+    }
+    resetFontEngineCache();
+}
 
 void QTextEngine::indexAdditionalFormats()
 {
@@ -2775,13 +2821,9 @@ void QTextEngine::resolveAdditionalFormats() const
         }
 
         foreach (int cur, currentFormats) {
-            const QTextLayout::FormatRange &r = specialData->addFormats.at(cur);
-            Q_ASSERT (r.start <= si->position && r.start + r.length >= end);
-            if (!specialData->addFormatIndices.isEmpty()) {
-                format.merge(collection->format(specialData->addFormatIndices.at(cur)));
-            } else {
-                format.merge(r.format);
-            }
+            Q_ASSERT(specialData->addFormats.at(cur).start <= si->position
+                     && specialData->addFormats.at(cur).start + specialData->addFormats.at(cur).length >= end);
+            format.merge(collection->format(specialData->addFormatIndices.at(cur)));
         }
         indices[i] = collection->indexForFormat(format);
     }
diff --git a/src/gui/text/qtextengine_p.h b/src/gui/text/qtextengine_p.h
index 88bc5dcc4c..ec7f7407b2 100644
--- a/src/gui/text/qtextengine_p.h
+++ b/src/gui/text/qtextengine_p.h
@@ -617,13 +617,23 @@ public:
     ItemDecorationList strikeOutList;
     ItemDecorationList overlineList;
 
-    inline bool hasFormats() const { return (block.docHandle() || specialData); }
     inline bool visualCursorMovement() const
     {
         return (visualMovement ||
                 (block.docHandle() ? block.docHandle()->defaultCursorMoveStyle == Qt::VisualMoveStyle : false));
     }
 
+    inline int preeditAreaPosition() const { return specialData ? specialData->preeditPosition : -1; }
+    inline QString preeditAreaText() const { return specialData ? specialData->preeditText : QString(); }
+    void setPreeditArea(int position, const QString &text);
+
+    inline bool hasFormats() const { return block.docHandle() || (specialData && !specialData->addFormats.isEmpty()); }
+    QList<QTextLayout::FormatRange> additionalFormats() const;
+    void setAdditionalFormats(const QList<QTextLayout::FormatRange> &formatList);
+
+private:
+    static void init(QTextEngine *e);
+
     struct SpecialData {
         int preeditPosition;
         QString preeditText;
@@ -635,9 +645,12 @@ public:
     };
     SpecialData *specialData;
 
+    void indexAdditionalFormats();
+    void resolveAdditionalFormats() const;
+
+public:
     bool atWordSeparator(int position) const;
     bool atSpace(int position) const;
-    void indexAdditionalFormats();
 
     QString elidedText(Qt::TextElideMode mode, const QFixed &width, int flags = 0, int from = 0, int count = -1) const;
 
@@ -675,7 +688,6 @@ private:
     void shapeTextWithHarfbuzz(int item) const;
     void splitItem(int item, int pos) const;
 
-    void resolveAdditionalFormats() const;
     int endOfLine(int lineNum);
     int beginningOfLine(int lineNum);
     int getClusterLength(unsigned short *logClusters, const QCharAttributes *attributes, int from, int to, int glyph_pos, int *start);
diff --git a/src/gui/text/qtextlayout.cpp b/src/gui/text/qtextlayout.cpp
index 50908f9908..eed6758cc9 100644
--- a/src/gui/text/qtextlayout.cpp
+++ b/src/gui/text/qtextlayout.cpp
@@ -463,24 +463,10 @@ const QTextOption &QTextLayout::textOption() const
 */
 void QTextLayout::setPreeditArea(int position, const QString &text)
 {
-    if (text.isEmpty()) {
-        if (!d->specialData)
-            return;
-        if (d->specialData->addFormats.isEmpty()) {
-            delete d->specialData;
-            d->specialData = 0;
-        } else {
-            d->specialData->preeditText = QString();
-            d->specialData->preeditPosition = -1;
-        }
-    } else {
-        if (!d->specialData)
-            d->specialData = new QTextEngine::SpecialData;
-        d->specialData->preeditPosition = position;
-        d->specialData->preeditText = text;
-    }
-    d->invalidate();
-    d->clearLineData();
+    if (d->preeditAreaPosition() == position && d->preeditAreaText() == text)
+        return;
+    d->setPreeditArea(position, text);
+
     if (d->block.docHandle())
         d->block.docHandle()->documentChange(d->block.position(), d->block.length());
 }
@@ -493,7 +479,7 @@ void QTextLayout::setPreeditArea(int position, const QString &text)
 */
 int QTextLayout::preeditAreaPosition() const
 {
-    return d->specialData ? d->specialData->preeditPosition : -1;
+    return d->preeditAreaPosition();
 }
 
 /*!
@@ -503,7 +489,7 @@ int QTextLayout::preeditAreaPosition() const
 */
 QString QTextLayout::preeditAreaText() const
 {
-    return d->specialData ? d->specialData->preeditText : QString();
+    return d->preeditAreaText();
 }
 
 
@@ -515,27 +501,10 @@ QString QTextLayout::preeditAreaText() const
 */
 void QTextLayout::setAdditionalFormats(const QList<FormatRange> &formatList)
 {
-    if (formatList.isEmpty()) {
-        if (!d->specialData)
-            return;
-        if (d->specialData->preeditText.isEmpty()) {
-            delete d->specialData;
-            d->specialData = 0;
-        } else {
-            d->specialData->addFormats = formatList;
-            d->specialData->addFormatIndices.clear();
-        }
-    } else {
-        if (!d->specialData) {
-            d->specialData = new QTextEngine::SpecialData;
-            d->specialData->preeditPosition = -1;
-        }
-        d->specialData->addFormats = formatList;
-        d->indexAdditionalFormats();
-    }
+    d->setAdditionalFormats(formatList);
+
     if (d->block.docHandle())
         d->block.docHandle()->documentChange(d->block.position(), d->block.length());
-    d->resetFontEngineCache();
 }
 
 /*!
@@ -545,21 +514,7 @@ void QTextLayout::setAdditionalFormats(const QList<FormatRange> &formatList)
 */
 QList<QTextLayout::FormatRange> QTextLayout::additionalFormats() const
 {
-    QList<FormatRange> formats;
-    if (!d->specialData)
-        return formats;
-
-    formats = d->specialData->addFormats;
-
-    if (d->specialData->addFormatIndices.isEmpty())
-        return formats;
-
-    const QTextFormatCollection *collection = d->formats();
-
-    for (int i = 0; i < d->specialData->addFormatIndices.count(); ++i)
-        formats[i].format = collection->charFormat(d->specialData->addFormatIndices.at(i));
-
-    return formats;
+    return d->additionalFormats();
 }
 
 /*!