1 files changed, 65 insertions, 0 deletions
diff --git a/libs/gui/FrameRateUtils.cpp b/libs/gui/FrameRateUtils.cpp
new file mode 100644
index 0000000000..6993bfab45
--- /dev/null
+++ b/libs/gui/FrameRateUtils.cpp
@@ -0,0 +1,65 @@
+/*
+ * 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.
+ */
+
+#include <gui/Flags.h>
+#include <gui/FrameRateUtils.h>
+#include <system/window.h>
+#include <utils/Log.h>
+
+#include <cmath>
+
+namespace android {
+// Returns true if the frameRate is valid.
+//
+// @param frameRate the frame rate in Hz
+// @param compatibility a ANATIVEWINDOW_FRAME_RATE_COMPATIBILITY_*
+// @param changeFrameRateStrategy a ANATIVEWINDOW_CHANGE_FRAME_RATE_*
+// @param functionName calling function or nullptr. Used for logging
+// @param privileged whether caller has unscoped surfaceflinger access
+bool ValidateFrameRate(float frameRate, int8_t compatibility, int8_t changeFrameRateStrategy,
+                       const char* inFunctionName, bool privileged) {
+    const char* functionName = inFunctionName != nullptr ? inFunctionName : "call";
+    int floatClassification = std::fpclassify(frameRate);
+    if (frameRate < 0 || floatClassification == FP_INFINITE || floatClassification == FP_NAN) {
+        ALOGE("%s failed - invalid frame rate %f", functionName, frameRate);
+        return false;
+    }
+
+    if (compatibility != ANATIVEWINDOW_FRAME_RATE_COMPATIBILITY_DEFAULT &&
+        compatibility != ANATIVEWINDOW_FRAME_RATE_COMPATIBILITY_FIXED_SOURCE &&
+        (!privileged ||
+         (compatibility != ANATIVEWINDOW_FRAME_RATE_EXACT &&
+          compatibility != ANATIVEWINDOW_FRAME_RATE_NO_VOTE))) {
+        ALOGE("%s failed - invalid compatibility value %d privileged: %s", functionName,
+              compatibility, privileged ? "yes" : "no");
+        return false;
+    }
+
+    if (__builtin_available(android 31, *)) {
+        if (changeFrameRateStrategy != ANATIVEWINDOW_CHANGE_FRAME_RATE_ONLY_IF_SEAMLESS &&
+            changeFrameRateStrategy != ANATIVEWINDOW_CHANGE_FRAME_RATE_ALWAYS) {
+            ALOGE("%s failed - invalid change frame rate strategy value %d", functionName,
+                  changeFrameRateStrategy);
+            if (FLAG_BQ_SET_FRAME_RATE) {
+                return false;
+            }
+        }
+    }
+
+    return true;
+}
+
+} // namespace android