TTF Prog

src/dawnshared/CMakeLists.txt

@@ -18,6 +18,7 @@ set(
   DAWN_SHARED_SOURCES
     ${D}/assert/assert.cpp
     ${D}/util/Xml.cpp
+    ${D}/util/UsageLock.cpp
 
   CACHE INTERNAL
     ${DAWN_CACHE_TARGET}

src/dawnshared/util/UsageLock.cpp

@@ -0,0 +1,27 @@
+// Copyright (c) 2023 Dominic Masters
+// 
+// This software is released under the MIT License.
+// https://opensource.org/licenses/MIT
+
+#include "util/UsageLock.hpp"
+
+using namespace Dawn;
+
+UsageLock::UsageLock() {
+  this->onEmpty = []() {};
+  this->onFirstLock = []() {};
+}
+
+usagelockid_t UsageLock::createLock() {
+  usagelockid_t lock = this->nextLock++;
+  this->locks.push_back(lock);
+  if(this->locks.size() == 1) this->onFirstLock();
+  return lock;
+}
+
+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);
+  if(this->locks.size() == 0) this->onEmpty();
+}

src/dawnshared/util/UsageLock.hpp

@@ -0,0 +1,39 @@
+// Copyright (c) 2023 Dominic Masters
+// 
+// This software is released under the MIT License.
+// https://opensource.org/licenses/MIT
+
+#include "assert/assert.hpp"
+
+namespace Dawn {
+  typedef uint32_t usagelockid_t;
+
+  class UsageLock {
+    protected:
+      usagelockid_t nextLock = 0;
+      std::vector<usagelockid_t> locks;
+
+    public:
+      std::function<void()> onEmpty;
+      std::function<void()> onFirstLock;
+
+      /**
+       * Construct a new usage lock object.
+       */
+      UsageLock();
+
+      /**
+       * Creates a new lock.
+       * 
+       * @return Lock created for this specific instance.
+       */
+      usagelockid_t createLock();
+
+      /**
+       * Removes a lock.
+       * 
+       * @param lock Lck to remove.
+       */
+      void removeLock(usagelockid_t lock);
+  };
+}