Add dump of hdr event history
Track & dump the HDRLayerInfo callback history to
aid debugging when HDR brightness changes aren't
happening
Bug: 234181960
Test: adb shell dumpsys surfaceflinger --hdrinfo
Change-Id: Ia8376517877d4c7844af6be4d488299554c164f5
diff --git a/services/surfaceflinger/Utils/RingBuffer.h b/services/surfaceflinger/Utils/RingBuffer.h
new file mode 100644
index 0000000..198e7b2
--- /dev/null
+++ b/services/surfaceflinger/Utils/RingBuffer.h
@@ -0,0 +1,68 @@
+/*
+ * Copyright 2023 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#pragma once
+
+#include <stddef.h>
+#include <array>
+
+namespace android::utils {
+
+template <class T, size_t SIZE>
+class RingBuffer {
+ RingBuffer(const RingBuffer&) = delete;
+ void operator=(const RingBuffer&) = delete;
+
+public:
+ RingBuffer() = default;
+ ~RingBuffer() = default;
+
+ constexpr size_t capacity() const { return SIZE; }
+
+ size_t size() const { return mCount; }
+
+ T& next() {
+ mHead = static_cast<size_t>(mHead + 1) % SIZE;
+ if (mCount < SIZE) {
+ mCount++;
+ }
+ return mBuffer[static_cast<size_t>(mHead)];
+ }
+
+ T& front() { return (*this)[0]; }
+
+ T& back() { return (*this)[size() - 1]; }
+
+ T& operator[](size_t index) {
+ return mBuffer[(static_cast<size_t>(mHead + 1) + index) % mCount];
+ }
+
+ const T& operator[](size_t index) const {
+ return mBuffer[(static_cast<size_t>(mHead + 1) + index) % mCount];
+ }
+
+ void clear() {
+ mCount = 0;
+ mHead = -1;
+ }
+
+private:
+ std::array<T, SIZE> mBuffer;
+ int mHead = -1;
+ size_t mCount = 0;
+};
+
+} // namespace android::utils