Fixed bug with VN scrolling

src/dawnshared/util/UsageLock.cpp

@@ -7,13 +7,18 @@
 
 using namespace Dawn;
 
-UsageLock::UsageLock() {
+UsageLock::UsageLock() : UsageLock(&this->internalPool) {
+}
+
+UsageLock::UsageLock(usagelockid_t *lockPool) {
+  assertNotNull(lockPool);
+  this->pool = lockPool;
   this->onEmpty = []() {};
   this->onFirstLock = []() {};
 }
 
 usagelockid_t UsageLock::createLock() {
-  usagelockid_t lock = this->nextLock++;
+  usagelockid_t lock = (*this->pool)++;
   this->locks.push_back(lock);
   if(this->locks.size() == 1) this->onFirstLock();
   return lock;
@@ -23,5 +28,6 @@ void UsageLock::removeLock(usagelockid_t lock) {
   auto it = std::find(this->locks.begin(), this->locks.end(), lock);
   if(it == this->locks.end()) return;
   this->locks.erase(it);
+  this->onLockRemoved(lock);
   if(this->locks.size() == 0) this->onEmpty();
 }

src/dawnshared/util/UsageLock.hpp

@@ -10,18 +10,27 @@ namespace Dawn {
 
   class UsageLock {
     protected:
-      usagelockid_t nextLock = 0;
+      usagelockid_t internalPool = 0;
+      usagelockid_t *pool = nullptr;
       std::vector<usagelockid_t> locks;
 
     public:
       std::function<void()> onEmpty;
       std::function<void()> onFirstLock;
+      std::function<void(usagelockid_t)> onLockRemoved;
 
       /**
        * Construct a new usage lock object.
        */
       UsageLock();
 
+      /**
+       * Construct a new Usage Lock object
+       * 
+       * @param lockPool Pool that will be used to create locks.
+       */
+      UsageLock(usagelockid_t *lockPool);
+
       /**
        * Creates a new lock.
        *