Refactor and document QQuickChangeSet.

Store an offset variable for moves so that an insert can be split
without the need to also split the corresponding remove, simplifying the
logic involved somewhat.

Change-Id: I1df19d431a04361a75e107bc4d149cbb80cd791d
Reviewed-by: Bea Lam <bea.lam@nokia.com>

1 files changed, 19 insertions, 24 deletions

diff --git a/src/quick/util/qquickchangeset_p.h b/src/quick/util/qquickchangeset_p.h
index 04a1e77c24..31a9c7bcbc 100644
--- a/src/quick/util/qquickchangeset_p.h
+++ b/src/quick/util/qquickchangeset_p.h
@@ -72,16 +72,18 @@ public:
     struct Change
     {
         Change() : index(0), count(0), moveId(-1) {}
-        Change(int index, int count) : index(index), count(count), moveId(-1) {}
-        Change(int index, int count, int moveId) : index(index), count(count), moveId(moveId) {}
+        Change(int index, int count, int moveId = -1, int offset = 0)
+            : index(index), count(count), moveId(moveId), offset(offset) {}
 
         int index;
         int count;
         int moveId;
+        int offset;
 
         bool isMove() const { return moveId >= 0; }
 
-        MoveKey moveKey(int index) const { return MoveKey(moveId, index - Change::index); }
+        MoveKey moveKey(int index) const {
+            return MoveKey(moveId, index - Change::index + offset); }
 
         int start() const { return index; }
         int end() const { return index + count; }
@@ -91,15 +93,15 @@ public:
     struct Insert : public Change
     {
         Insert() {}
-        Insert(int index, int count) : Change(index, count) {}
-        Insert(int index, int count, int moveId) : Change(index, count, moveId) {}
+        Insert(int index, int count, int moveId = -1, int offset = 0)
+            : Change(index, count, moveId, offset) {}
     };
 
     struct Remove : public Change
     {
         Remove() {}
-        Remove(int index, int count) : Change(index, count) {}
-        Remove(int index, int count, int moveId) : Change(index, count, moveId) {}
+        Remove(int index, int count, int moveId = -1, int offset = 0)
+            : Change(index, count, moveId, offset) {}
     };
 
     QQuickChangeSet();
@@ -110,45 +112,38 @@ public:
 
     const QVector<Remove> &removes() const { return m_removes; }
     const QVector<Insert> &inserts() const { return m_inserts; }
-    const QVector<Change> &changes() const {return  m_changes; }
+    const QVector<Change> &changes() const { return m_changes; }
 
     void insert(int index, int count);
     void remove(int index, int count);
-    void move(int from, int to, int count);
+    void move(int from, int to, int count, int moveId);
     void change(int index, int count);
 
+    void insert(const QVector<Insert> &inserts);
+    void remove(const QVector<Remove> &removes, QVector<Insert> *inserts = 0);
+    void move(const QVector<Remove> &removes, const QVector<Insert> &inserts);
+    void change(const QVector<Change> &changes);
     void apply(const QQuickChangeSet &changeSet);
-    void apply(const QVector<Remove> &removals);
-    void apply(const QVector<Insert> &insertions);
-    void apply(const QVector<Change> &changes);
-    void apply(
-            const QVector<Remove> &removals,
-            const QVector<Insert> &insertions,
-            const QVector<Change> &changes = QVector<Change>());
 
-    bool isEmpty() const { return m_removes.empty() && m_inserts.empty() && m_changes.empty(); }
+    bool isEmpty() const { return m_removes.empty() && m_inserts.empty() && m_changes.isEmpty(); }
 
     void clear()
     {
         m_removes.clear();
         m_inserts.clear();
         m_changes.clear();
-        m_moveCounter = 0;
         m_difference = 0;
     }
 
-    int moveCounter() const { return m_moveCounter; }
     int difference() const { return m_difference; }
 
 private:
-    void applyRemovals(QVector<Remove> &removals, QVector<Insert> &insertions);
-    void applyInsertions(QVector<Insert> &insertions);
-    void applyChanges(QVector<Change> &changes);
+    void remove(QVector<Remove> *removes, QVector<Insert> *inserts);
+    void change(QVector<Change> *changes);
 
     QVector<Remove> m_removes;
     QVector<Insert> m_inserts;
     QVector<Change> m_changes;
-    int m_moveCounter;
     int m_difference;
 };
 
@@ -161,10 +156,10 @@ inline uint qHash(const QQuickChangeSet::MoveKey &key) { return qHash(qMakePair(
 inline bool operator ==(const QQuickChangeSet::MoveKey &l, const QQuickChangeSet::MoveKey &r) {
     return l.moveId == r.moveId && l.offset == r.offset; }
 
-Q_AUTOTEST_EXPORT QDebug operator <<(QDebug debug, const QQuickChangeSet &change);
 Q_AUTOTEST_EXPORT QDebug operator <<(QDebug debug, const QQuickChangeSet::Remove &remove);
 Q_AUTOTEST_EXPORT QDebug operator <<(QDebug debug, const QQuickChangeSet::Insert &insert);
 Q_AUTOTEST_EXPORT QDebug operator <<(QDebug debug, const QQuickChangeSet::Change &change);
+Q_AUTOTEST_EXPORT QDebug operator <<(QDebug debug, const QQuickChangeSet &change);
 
 QT_END_NAMESPACE