Use a QDoubleEndedList for the children of animation group jobs

This way it's fundamentally impossible to add the same animation job to
two different group jobs. The pointers are not exposed anymore and no
one can re-order the jobs.

Task-number: QTBUG-90401
Change-Id: Iebff4b64960c853915dd32714acd144fc5cdc00d
Reviewed-by: Fabian Kosmale <fabian.kosmale@qt.io>

1 files changed, 41 insertions, 32 deletions

diff --git a/src/qml/animations/qsequentialanimationgroupjob.cpp b/src/qml/animations/qsequentialanimationgroupjob.cpp
index 1d19bbf79d..2da6c79e29 100644
--- a/src/qml/animations/qsequentialanimationgroupjob.cpp
+++ b/src/qml/animations/qsequentialanimationgroupjob.cpp
@@ -66,11 +66,12 @@ bool QSequentialAnimationGroupJob::atEnd() const
     const int animTotalCurrentTime = m_currentAnimation->currentTime();
     return (m_currentLoop == m_loopCount - 1
         && m_direction == Forward
-        && !m_currentAnimation->nextSibling()
+        && !m_children.next(m_currentAnimation)
         && animTotalCurrentTime == animationActualTotalDuration(m_currentAnimation));
 }
 
-int QSequentialAnimationGroupJob::animationActualTotalDuration(QAbstractAnimationJob *anim) const
+int QSequentialAnimationGroupJob::animationActualTotalDuration(
+        const QAbstractAnimationJob *anim) const
 {
     int ret = anim->totalDuration();
     if (ret == -1) {
@@ -84,13 +85,12 @@ int QSequentialAnimationGroupJob::animationActualTotalDuration(QAbstractAnimatio
 
 QSequentialAnimationGroupJob::AnimationIndex QSequentialAnimationGroupJob::indexForCurrentTime() const
 {
-    Q_ASSERT(firstChild());
+    Q_ASSERT(!m_children.isEmpty());
 
     AnimationIndex ret;
-    QAbstractAnimationJob *anim = nullptr;
     int duration = 0;
 
-    for (anim = firstChild(); anim; anim = anim->nextSibling()) {
+    for (const QAbstractAnimationJob *anim : m_children) {
         duration = animationActualTotalDuration(anim);
 
         // 'animation' is the current animation if one of these reasons is true:
@@ -116,7 +116,7 @@ QSequentialAnimationGroupJob::AnimationIndex QSequentialAnimationGroupJob::index
     // 1. the duration of the group is undefined and we passed its actual duration
     // 2. there are only 0-duration animations in the group
     ret.timeOffset -= duration;
-    ret.animation = lastChild();
+    ret.animation = m_children.last();
     return ret;
 }
 
@@ -125,17 +125,17 @@ void QSequentialAnimationGroupJob::restart()
     // restarting the group by making the first/last animation the current one
     if (m_direction == Forward) {
         m_previousLoop = 0;
-        if (m_currentAnimation == firstChild())
+        if (m_currentAnimation == m_children.first())
             activateCurrentAnimation();
         else
-            setCurrentAnimation(firstChild());
+            setCurrentAnimation(m_children.first());
     }
     else { // direction == Backward
         m_previousLoop = m_loopCount - 1;
-        if (m_currentAnimation == lastChild())
+        if (m_currentAnimation == m_children.last())
             activateCurrentAnimation();
         else
-            setCurrentAnimation(lastChild());
+            setCurrentAnimation(m_children.last());
     }
 }
 
@@ -143,21 +143,22 @@ void QSequentialAnimationGroupJob::advanceForwards(const AnimationIndex &newAnim
 {
     if (m_previousLoop < m_currentLoop) {
         // we need to fast forward to the end
-        for (QAbstractAnimationJob *anim = m_currentAnimation; anim; anim = anim->nextSibling()) {
+        for (QAbstractAnimationJob *anim = m_currentAnimation; anim; anim = m_children.next(anim)) {
             RETURN_IF_DELETED(setCurrentAnimation(anim, true));
             RETURN_IF_DELETED(anim->setCurrentTime(animationActualTotalDuration(anim)));
         }
         // this will make sure the current animation is reset to the beginning
-        if (firstChild() && !firstChild()->nextSibling()) {   //count == 1
+        if (m_children.count() == 1) {
             // we need to force activation because setCurrentAnimation will have no effect
             RETURN_IF_DELETED(activateCurrentAnimation());
         } else {
-            RETURN_IF_DELETED(setCurrentAnimation(firstChild(), true));
+            RETURN_IF_DELETED(setCurrentAnimation(m_children.first(), true));
         }
     }
 
     // and now we need to fast forward from the current position to
-    for (QAbstractAnimationJob *anim = m_currentAnimation; anim && anim != newAnimationIndex.animation; anim = anim->nextSibling()) {     //### WRONG,
+    for (QAbstractAnimationJob *anim = m_currentAnimation;
+         anim && anim != newAnimationIndex.animation; anim = m_children.next(anim)) {     //### WRONG,
         RETURN_IF_DELETED(setCurrentAnimation(anim, true));
         RETURN_IF_DELETED(anim->setCurrentTime(animationActualTotalDuration(anim)));
     }
@@ -168,21 +169,23 @@ void QSequentialAnimationGroupJob::rewindForwards(const AnimationIndex &newAnima
 {
     if (m_previousLoop > m_currentLoop) {
         // we need to fast rewind to the beginning
-        for (QAbstractAnimationJob *anim = m_currentAnimation; anim; anim = anim->previousSibling()) {
+        for (QAbstractAnimationJob *anim = m_currentAnimation; anim;
+             anim = m_children.prev(anim)) {
             RETURN_IF_DELETED(setCurrentAnimation(anim, true));
             RETURN_IF_DELETED(anim->setCurrentTime(0));
         }
         // this will make sure the current animation is reset to the end
-        if (lastChild() && !lastChild()->previousSibling()) {   //count == 1
+        if (m_children.count() == 1) {   //count == 1
             // we need to force activation because setCurrentAnimation will have no effect
             RETURN_IF_DELETED(activateCurrentAnimation());
         } else {
-            RETURN_IF_DELETED(setCurrentAnimation(lastChild(), true));
+            RETURN_IF_DELETED(setCurrentAnimation(m_children.last(), true));
         }
     }
 
     // and now we need to fast rewind from the current position to
-    for (QAbstractAnimationJob *anim = m_currentAnimation; anim && anim != newAnimationIndex.animation; anim = anim->previousSibling()) {
+    for (QAbstractAnimationJob *anim = m_currentAnimation;
+         anim && anim != newAnimationIndex.animation; anim = m_children.prev(anim)) {
         RETURN_IF_DELETED(setCurrentAnimation(anim, true));
         RETURN_IF_DELETED(anim->setCurrentTime(0));
     }
@@ -193,7 +196,7 @@ int QSequentialAnimationGroupJob::duration() const
 {
     int ret = 0;
 
-    for (QAbstractAnimationJob *anim = firstChild(); anim; anim = anim->nextSibling()) {
+    for (const QAbstractAnimationJob *anim : m_children) {
         const int currentDuration = anim->totalDuration();
         if (currentDuration == -1)
             return -1; // Undetermined length
@@ -246,7 +249,7 @@ void QSequentialAnimationGroupJob::updateCurrentTime(int currentTime)
     } else {
         //the only case where currentAnimation could be null
         //is when all animations have been removed
-        Q_ASSERT(!firstChild());
+        Q_ASSERT(m_children.isEmpty());
         m_currentTime = 0;
         RETURN_IF_DELETED(stop());
     }
@@ -288,10 +291,11 @@ void QSequentialAnimationGroupJob::updateDirection(QAbstractAnimationJob::Direct
         m_currentAnimation->setDirection(direction);
 }
 
-void QSequentialAnimationGroupJob::setCurrentAnimation(QAbstractAnimationJob *anim, bool intermediate)
+void QSequentialAnimationGroupJob::setCurrentAnimation(
+        const QAbstractAnimationJob *anim, bool intermediate)
 {
     if (!anim) {
-        Q_ASSERT(!firstChild());
+        Q_ASSERT(m_children.isEmpty());
         m_currentAnimation = nullptr;
         return;
     }
@@ -303,7 +307,12 @@ void QSequentialAnimationGroupJob::setCurrentAnimation(QAbstractAnimationJob *an
     if (m_currentAnimation)
         m_currentAnimation->stop();
 
-    m_currentAnimation = anim;
+    // Assert that the animation passed as argument is actually part of this group ...
+    Q_ASSERT(m_children.contains(anim));
+
+    // ... as then this const_cast is just a shortcut for looking up the non-const
+    // pointer in the linked list of jobs.
+    m_currentAnimation = const_cast<QAbstractAnimationJob *>(anim);
 
     activateCurrentAnimation(intermediate);
 }
@@ -337,10 +346,10 @@ void QSequentialAnimationGroupJob::uncontrolledAnimationFinished(QAbstractAnimat
     int totalTime = currentTime();
     if (m_direction == Forward) {
         // set the current animation to be the next one
-        if (m_currentAnimation->nextSibling())
-            RETURN_IF_DELETED(setCurrentAnimation(m_currentAnimation->nextSibling()));
+        if (auto *anim = m_children.next(m_currentAnimation))
+            RETURN_IF_DELETED(setCurrentAnimation(anim));
 
-        for (QAbstractAnimationJob *a = animation->nextSibling(); a; a = a->nextSibling()) {
+        for (QAbstractAnimationJob *a = m_children.next(animation); a; a = m_children.next(a)) {
             int dur = a->duration();
             if (dur == -1) {
                 totalTime = -1;
@@ -352,10 +361,10 @@ void QSequentialAnimationGroupJob::uncontrolledAnimationFinished(QAbstractAnimat
 
     } else {
         // set the current animation to be the previous one
-        if (m_currentAnimation->previousSibling())
-            RETURN_IF_DELETED(setCurrentAnimation(m_currentAnimation->previousSibling()));
+        if (auto *anim = m_children.prev(m_currentAnimation))
+            RETURN_IF_DELETED(setCurrentAnimation(anim));
 
-        for (QAbstractAnimationJob *a = animation->previousSibling(); a; a = a->previousSibling()) {
+        for (QAbstractAnimationJob *a = m_children.prev(animation); a; a = m_children.prev(a)) {
             int dur = a->duration();
             if (dur == -1) {
                 totalTime = -1;
@@ -374,9 +383,9 @@ void QSequentialAnimationGroupJob::uncontrolledAnimationFinished(QAbstractAnimat
 void QSequentialAnimationGroupJob::animationInserted(QAbstractAnimationJob *anim)
 {
     if (m_currentAnimation == nullptr)
-        RETURN_IF_DELETED(setCurrentAnimation(firstChild())); // initialize the current animation
+        RETURN_IF_DELETED(setCurrentAnimation(m_children.first())); // initialize the current animation
 
-    if (m_currentAnimation == anim->nextSibling()
+    if (m_currentAnimation == m_children.next(anim)
         && m_currentAnimation->currentTime() == 0 && m_currentAnimation->currentLoop() == 0) {
             //in this case we simply insert the animation before the current one has actually started
             RETURN_IF_DELETED(setCurrentAnimation(anim));
@@ -407,7 +416,7 @@ void QSequentialAnimationGroupJob::animationRemoved(QAbstractAnimationJob *anim,
 
     // duration of the previous animations up to the current animation
     m_currentTime = 0;
-    for (QAbstractAnimationJob *job = firstChild(); job; job = job->nextSibling()) {
+    for (QAbstractAnimationJob *job : m_children) {
         if (job == m_currentAnimation)
             break;
         m_currentTime += animationActualTotalDuration(job);