1 files changed, 29 insertions, 32 deletions
diff --git a/platform/darwin/src/headless_backend_eagl.mm b/platform/darwin/src/headless_backend_eagl.mm
index 1daaeaf54c..050fa62c78 100644
--- a/platform/darwin/src/headless_backend_eagl.mm
+++ b/platform/darwin/src/headless_backend_eagl.mm
@@ -6,51 +6,48 @@
 
 namespace mbgl {
 
-struct EAGLImpl : public HeadlessBackend::Impl {
-    EAGLImpl(EAGLContext* glContext_) : glContext(glContext_) {
-        [reinterpret_cast<EAGLContext*>(glContext) retain];
-        reinterpret_cast<EAGLContext*>(glContext).multiThreaded = YES;
+class EAGLBackendImpl : public HeadlessBackend::Impl {
+public:
+    EAGLBackendImpl() {
+        glContext = [[EAGLContext alloc] initWithAPI:kEAGLRenderingAPIOpenGLES2];
+        if (glContext == nil) {
+            throw std::runtime_error("Error creating GL context object");
+        }
+        glContext.multiThreaded = YES;
     }
 
-    ~EAGLImpl() {
-        [glContext release];
+    // Required for ARC to deallocate correctly.
+    ~EAGLBackendImpl() final = default;
+
+    gl::ProcAddress getExtensionFunctionPointer(const char* name) final {
+        static CFBundleRef framework = CFBundleGetBundleWithIdentifier(CFSTR("com.apple.opengles"));
+        if (!framework) {
+            throw std::runtime_error("Failed to load OpenGL framework.");
+        }
+
+        CFStringRef str =
+            CFStringCreateWithCString(kCFAllocatorDefault, name, kCFStringEncodingASCII);
+        void* symbol = CFBundleGetFunctionPointerForName(framework, str);
+        CFRelease(str);
+
+        return reinterpret_cast<gl::ProcAddress>(symbol);
     }
 
-    void activateContext() {
+    void activateContext() final {
         [EAGLContext setCurrentContext:glContext];
     }
 
-    void deactivateContext() {
+    void deactivateContext() final {
         [EAGLContext setCurrentContext:nil];
     }
 
+private:
     EAGLContext* glContext = nullptr;
 };
 
-gl::ProcAddress HeadlessBackend::initializeExtension(const char* name) {
-    static CFBundleRef framework = CFBundleGetBundleWithIdentifier(CFSTR("com.apple.opengles"));
-    if (!framework) {
-        throw std::runtime_error("Failed to load OpenGL framework.");
-    }
-
-    CFStringRef str = CFStringCreateWithCString(kCFAllocatorDefault, name, kCFStringEncodingASCII);
-    void* symbol = CFBundleGetFunctionPointerForName(framework, str);
-    CFRelease(str);
-
-    return reinterpret_cast<gl::ProcAddress>(symbol);
-}
-
-bool HeadlessBackend::hasDisplay() {
-    return true;
-}
-
-void HeadlessBackend::createContext() {
-    EAGLContext* glContext = [[EAGLContext alloc] initWithAPI:kEAGLRenderingAPIOpenGLES2];
-    if (glContext == nil) {
-        throw std::runtime_error("Error creating GL context object");
-    }
-
-    impl.reset(new EAGLImpl(glContext));
+void HeadlessBackend::createImpl() {
+    assert(!impl);
+    impl = std::make_unique<EAGLBackendImpl>();
 }
 
 } // namespace mbgl