1 files changed, 47 insertions, 0 deletions
diff --git a/src/mbgl/renderer/backend_scope.cpp b/src/mbgl/renderer/backend_scope.cpp
new file mode 100644
index 0000000000..5d57421c48
--- /dev/null
+++ b/src/mbgl/renderer/backend_scope.cpp
@@ -0,0 +1,47 @@
+#include <mbgl/renderer/backend_scope.hpp>
+#include <mbgl/renderer/renderer_backend.hpp>
+#include <mbgl/util/thread_local.hpp>
+
+#include <cassert>
+
+namespace mbgl {
+
+static util::ThreadLocal<BackendScope> currentScope;
+
+BackendScope::BackendScope(RendererBackend& backend_, ScopeType scopeType_)
+    : priorScope(currentScope.get()),
+      nextScope(nullptr),
+      backend(backend_),
+      scopeType(scopeType_) {
+    if (priorScope) {
+        assert(priorScope->nextScope == nullptr);
+        priorScope->nextScope = this;
+    }
+    if (scopeType == ScopeType::Explicit) {
+        backend.activate();
+    }
+
+    currentScope.set(this);
+}
+
+BackendScope::~BackendScope() {
+    assert(nextScope == nullptr);
+    if (priorScope) {
+        priorScope->backend.activate();
+        currentScope.set(priorScope);
+        assert(priorScope->nextScope == this);
+        priorScope->nextScope = nullptr;
+    } else {
+        if (scopeType == ScopeType::Explicit) {
+            backend.deactivate();
+        }
+
+        currentScope.set(nullptr);
+    }
+}
+
+bool BackendScope::exists() {
+    return currentScope.get();
+}
+
+} // namespace mbgl