Avoid accessing sprites until they finish loading

Because sprite properties are not valid until image assembly finishes,
some features of the sprite engine cannot work until sprite assembly is
finished. In these circumstances, we shouldn't crash.

Task-number: QTBUG-24797
Change-Id: I2701f9302620c2cfd5b7bc5ce1cb9f31be4d4e19
Reviewed-by: Alan Alpert <alan.alpert@nokia.com>

1 files changed, 21 insertions, 5 deletions

diff --git a/src/quick/items/qquickspriteengine.cpp b/src/quick/items/qquickspriteengine.cpp
index 60d6eddb3d..1763d7acab 100644
--- a/src/quick/items/qquickspriteengine.cpp
+++ b/src/quick/items/qquickspriteengine.cpp
@@ -107,12 +107,12 @@ QQuickStochasticEngine::~QQuickStochasticEngine()
 }
 
 QQuickSpriteEngine::QQuickSpriteEngine(QObject *parent)
-    : QQuickStochasticEngine(parent), m_startedImageAssembly(false)
+    : QQuickStochasticEngine(parent), m_startedImageAssembly(false), m_loaded(false)
 {
 }
 
 QQuickSpriteEngine::QQuickSpriteEngine(QList<QQuickSprite*> sprites, QObject *parent)
-    : QQuickStochasticEngine(parent), m_startedImageAssembly(false)
+    : QQuickStochasticEngine(parent), m_startedImageAssembly(false), m_loaded(false)
 {
     foreach (QQuickSprite* sprite, sprites)
         m_states << (QQuickStochasticState*)sprite;
@@ -156,6 +156,8 @@ int QQuickSpriteEngine::pseudospriteProgress(int sprite, int state, int* rowDura
 
 int QQuickSpriteEngine::spriteState(int sprite)
 {
+    if (!m_loaded)
+        return 0;
     int state = m_things[sprite];
     if (!m_sprites[state]->m_generatedCount)
         return state;
@@ -175,7 +177,7 @@ int QQuickSpriteEngine::spriteState(int sprite)
 
 int QQuickSpriteEngine::spriteStart(int sprite)
 {
-    if (!m_duration[sprite])
+    if (!m_duration[sprite] || !m_loaded)
         return m_timeOffset;
     int state = m_things[sprite];
     if (!m_sprites[state]->m_generatedCount)
@@ -189,6 +191,8 @@ int QQuickSpriteEngine::spriteStart(int sprite)
 
 int QQuickSpriteEngine::spriteFrames(int sprite)
 {
+    if (!m_loaded)
+        return 1;
     int state = m_things[sprite];
     if (!m_sprites[state]->m_generatedCount)
         return m_sprites[state]->frames();
@@ -212,7 +216,7 @@ int QQuickSpriteEngine::spriteFrames(int sprite)
 
 int QQuickSpriteEngine::spriteDuration(int sprite)//Full duration, not per frame
 {
-    if (!m_duration[sprite])
+    if (!m_duration[sprite] || !m_loaded)
         return m_duration[sprite];
     int state = m_things[sprite];
     if (!m_sprites[state]->m_generatedCount)
@@ -230,6 +234,8 @@ int QQuickSpriteEngine::spriteDuration(int sprite)//Full duration, not per frame
 
 int QQuickSpriteEngine::spriteY(int sprite)
 {
+    if (!m_loaded)
+        return 0;
     int state = m_things[sprite];
     if (!m_sprites[state]->m_generatedCount)
         return m_sprites[state]->m_rowY;
@@ -250,6 +256,8 @@ int QQuickSpriteEngine::spriteY(int sprite)
 
 int QQuickSpriteEngine::spriteX(int sprite)
 {
+    if (!m_loaded)
+        return 0;
     int state = m_things[sprite];
     if (!m_sprites[state]->m_generatedCount)
         return m_sprites[state]->m_rowStartX;
@@ -339,6 +347,7 @@ void QQuickSpriteEngine::startAssemblingImage()
 {
     if (m_startedImageAssembly)
         return;
+    m_loaded = false;
 
     //This could also trigger the start of the image loading in Sprites, however that currently happens in Sprite::setSource
 
@@ -477,6 +486,8 @@ QImage QQuickSpriteEngine::assembledImage()
     qDebug() << "Assembled image output to: " << fPath.arg(acc);
 #endif
 
+    m_loaded = true;
+    m_startedImageAssembly = false;
     return image;
 }
 
@@ -530,7 +541,7 @@ void QQuickStochasticEngine::restart(int index)
 void QQuickSpriteEngine::restart(int index) //Reimplemented to recognize and handle pseudostates
 {
     bool randomStart = (m_startTimes[index] == NINF);
-    if (m_sprites[m_things[index]]->frameSync()) {//Manually advanced
+    if (m_loaded && m_sprites[m_things[index]]->frameSync()) {//Manually advanced
         m_startTimes[index] = 0;
         if (randomStart && m_sprites[m_things[index]]->m_generatedCount)
             m_startTimes[index] += qrand() % m_sprites[m_things[index]]->m_generatedCount;
@@ -567,6 +578,11 @@ void QQuickStochasticEngine::advance(int idx)
 
 void QQuickSpriteEngine::advance(int idx) //Reimplemented to recognize and handle pseudostates
 {
+    if (!m_loaded) {
+        qWarning() << QLatin1String("QQuickSpriteEngine: Trying to advance sprites before sprites finish loading. Ignoring directive");
+        return;
+    }
+
     if (idx >= m_things.count())
         return;//TODO: Proper fix(because this has happened and I just ignored it)
     if (m_duration[idx] == 0) {