lottie: release memory immediately after loading is complete.

there is no need to retain the data,
as the Lottie source is not reusable
and is affected by the parsing mechanism.

issue: https://github.com/thorvg/thorvg/issues/2647

src/loaders/lottie/tvgLottieLoader.cpp

@@ -44,11 +44,24 @@ void LottieLoader::run(unsigned tid)
             comp = parser.comp;
         }
         builder->build(comp);
+
+        release();
     }
     rebuild = false;
 }
 
 
+void LottieLoader::release()
+{
+    if (copy) {
+        free((char*)content);
+        content = nullptr;
+    }
+    free(dirName);
+    dirName = nullptr;
+}
+
+
 /************************************************************************/
 /* External Class Implementation                                        */
 /************************************************************************/
@@ -63,8 +76,7 @@ LottieLoader::~LottieLoader()
 {
     done();
 
-    if (copy) free((char*)content);
-    free(dirName);
+    release();
 
     //TODO: correct position?
     delete(comp);
@@ -76,6 +88,7 @@ bool LottieLoader::header()
 {
     //A single thread doesn't need to perform intensive tasks.
     if (TaskScheduler::threads() == 0) {
+        LoadModule::read();
         run(0);
         if (comp) {
             w = static_cast<float>(comp->w);
@@ -87,7 +100,6 @@ bool LottieLoader::header()
         } else {
             return false;
         }
-        LoadModule::read();
     }
 
     //Quickly validate the given Lottie file without parsing in order to get the animation info.
@@ -254,11 +266,11 @@ bool LottieLoader::resize(Paint* paint, float w, float h)
 
 bool LottieLoader::read()
 {
-    if (!content || size == 0) return false;
-
     //the loading has been already completed
     if (!LoadModule::read()) return true;
 
+    if (!content || size == 0) return false;
+
     TaskScheduler::request(this);
 
     return true;

src/loaders/lottie/tvgLottieLoader.h

@@ -77,6 +77,7 @@ private:
     void clear();
     float startFrame();
     void run(unsigned tid) override;
+    void release();
 };