ImageSaveLocationValidator.java
/*
* Copyright 2020 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.core;
import android.content.ContentResolver;
import android.content.ContentValues;
import android.net.Uri;
import androidx.annotation.NonNull;
import java.io.File;
import java.io.IOException;
import java.io.OutputStream;
class ImageSaveLocationValidator {
private static final String TAG = "SaveLocationValidator";
private ImageSaveLocationValidator() {
}
/**
* Verifies whether the result of an image capture operation can be saved to the specified
* location in {@link androidx.camera.core.ImageCapture.OutputFileOptions}.
* <p>
* This method checks whether an image capture to a {@link File} or to
* {@link android.provider.MediaStore} will work by checking whether the {@link File} exists
* and is writable, and if the {@link Uri} to {@link android.provider.MediaStore} is valid.
*
* @param outputFileOptions Options for saving the result of an image capture operation
* @return true if the image capture result can be saved to the specified storage option,
* false otherwise.
*/
@SuppressWarnings("ConstantConditions")
static boolean isValid(final @NonNull ImageCapture.OutputFileOptions outputFileOptions) {
if (isSaveToFile(outputFileOptions)) {
return canSaveToFile(outputFileOptions.getFile());
}
if (isSaveToMediaStore(outputFileOptions)) {
return canSaveToMediaStore(outputFileOptions.getContentResolver(),
outputFileOptions.getSaveCollection(), outputFileOptions.getContentValues());
}
return true;
}
private static boolean isSaveToFile(
final @NonNull ImageCapture.OutputFileOptions outputFileOptions) {
return outputFileOptions.getFile() != null;
}
private static boolean isSaveToMediaStore(
final @NonNull ImageCapture.OutputFileOptions outputFileOptions) {
return outputFileOptions.getSaveCollection() != null
&& outputFileOptions.getContentResolver() != null
&& outputFileOptions.getContentValues() != null;
}
private static boolean canSaveToFile(@NonNull final File file) {
try {
return file.canWrite();
} catch (SecurityException exception) {
Logger.e(TAG, "Error while verifying if image capture file is writable", exception);
return false;
}
}
private static boolean canSaveToMediaStore(@NonNull final ContentResolver contentResolver,
@NonNull final Uri uri, @NonNull ContentValues values) {
final Uri outputUri;
try {
// Get the uri where the image will be saved
outputUri = contentResolver.insert(uri, values);
} catch (IllegalArgumentException exception) {
Logger.e(TAG, "Failed to insert into " + uri.toString(), exception);
return false;
}
// If the uri is null, saving the capture result to the given uri isn't possible
if (outputUri == null) {
return false;
}
// Try opening a write stream to the output uri. If this succeeds, the image save
// destination is valid. Otherwise, it's invalid.
try (OutputStream stream = contentResolver.openOutputStream(outputUri)) {
return stream != null;
} catch (IOException exception) {
Logger.e(TAG, "Failed to open a write stream to" + outputUri.toString(), exception);
return false;
} finally {
try {
// Delete inserted row
contentResolver.delete(outputUri, null, null);
} catch (IllegalArgumentException exception) {
Logger.e(TAG, "Failed to delete inserted row at " + outputUri.toString(),
exception);
}
}
}
}