FlashAvailabilityChecker.java
/*
* Copyright 2022 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.
*/
package androidx.camera.camera2.internal.compat.workaround;
import android.hardware.camera2.CameraCharacteristics;
import androidx.annotation.NonNull;
import androidx.annotation.RequiresApi;
import androidx.camera.camera2.internal.compat.CameraCharacteristicsCompat;
import androidx.camera.camera2.internal.compat.quirk.DeviceQuirks;
import androidx.camera.camera2.internal.compat.quirk.FlashAvailabilityBufferUnderflowQuirk;
import androidx.camera.core.Logger;
import java.nio.BufferUnderflowException;
/**
* A workaround for devices which may throw a {@link java.nio.BufferUnderflowException} when
* checking flash availability.
*
* @see androidx.camera.camera2.internal.compat.quirk.FlashAvailabilityBufferUnderflowQuirk
*/
@RequiresApi(21) // TODO(b/200306659): Remove and replace with annotation on package-info.java
public final class FlashAvailabilityChecker {
private static final String TAG = "FlashAvailability";
/**
* Checks whether the camera characteristics advertise that flash is available safely.
*
* @param characteristics the characteristics to check for
* {@link CameraCharacteristics#FLASH_INFO_AVAILABLE}.
* @return the value of {@link CameraCharacteristics#FLASH_INFO_AVAILABLE} if it is contained
* in the characteristics, or {@code false} if it is not or a
* {@link java.nio.BufferUnderflowException} is thrown while checking.
*/
public static boolean isFlashAvailable(@NonNull CameraCharacteristicsCompat characteristics) {
if (DeviceQuirks.get(FlashAvailabilityBufferUnderflowQuirk.class) != null) {
Logger.d(TAG, "Device has quirk "
+ FlashAvailabilityBufferUnderflowQuirk.class.getSimpleName()
+ ". Checking for flash availability safely...");
return checkFlashAvailabilityWithPossibleBufferUnderflow(characteristics);
} else {
return checkFlashAvailabilityNormally(characteristics);
}
}
private static boolean checkFlashAvailabilityWithPossibleBufferUnderflow(
@NonNull CameraCharacteristicsCompat characteristics) {
try {
return checkFlashAvailabilityNormally(characteristics);
} catch (BufferUnderflowException e) {
return false;
}
}
private static boolean checkFlashAvailabilityNormally(
@NonNull CameraCharacteristicsCompat characteristics) {
Boolean flashAvailable =
characteristics.get(CameraCharacteristics.FLASH_INFO_AVAILABLE);
if (flashAvailable == null) {
Logger.w(TAG, "Characteristics did not contain key FLASH_INFO_AVAILABLE. Flash is not"
+ " available.");
}
return flashAvailable != null ? flashAvailable : false;
}
// Class should not be instantiated
private FlashAvailabilityChecker() {
}
}