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/*
* Copyright 2022 Google LLC
*
* 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 com.google.android.libraries.mobiledatadownload.downloader.inline;
import static com.google.android.libraries.mobiledatadownload.internal.MddConstants.INLINE_FILE_URL_SCHEME;
import com.google.android.libraries.mobiledatadownload.DownloadException;
import com.google.android.libraries.mobiledatadownload.DownloadException.DownloadResultCode;
import com.google.android.libraries.mobiledatadownload.downloader.DownloadRequest;
import com.google.android.libraries.mobiledatadownload.downloader.FileDownloader;
import com.google.android.libraries.mobiledatadownload.downloader.InlineDownloadParams;
import com.google.android.libraries.mobiledatadownload.file.SynchronousFileStorage;
import com.google.android.libraries.mobiledatadownload.file.openers.ReadStreamOpener;
import com.google.android.libraries.mobiledatadownload.file.openers.WriteStreamOpener;
import com.google.android.libraries.mobiledatadownload.internal.logging.LogUtil;
import com.google.common.io.ByteStreams;
import com.google.common.util.concurrent.Futures;
import com.google.common.util.concurrent.ListenableFuture;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.concurrent.Executor;
/**
* An implementation of {@link FileDownloader} that supports copying in-memory data to disk.
*
* <p>This implementation only supports copying for "inlinefile:" url schemes. For more details see
* <internal>.
*
* <p>NOTE: copying in-memory data can be thought of as "inline file downloading," hence the naming
* of this class.
*/
public final class InlineFileDownloader implements FileDownloader {
private static final String TAG = "InlineFileDownloader";
private final SynchronousFileStorage fileStorage;
private final Executor downloadExecutor;
/**
* Construct InlineFileDownloader instance.
*
* @param fileStorage a file storage instance used to perform I/O
* @param downloadExecutor executor that will perfrom the download. This should be
* the @MddDownloadExecutor
*/
public InlineFileDownloader(SynchronousFileStorage fileStorage, Executor downloadExecutor) {
this.fileStorage = fileStorage;
this.downloadExecutor = downloadExecutor;
}
@Override
public ListenableFuture<Void> startDownloading(DownloadRequest downloadRequest) {
if (!downloadRequest.urlToDownload().startsWith(INLINE_FILE_URL_SCHEME)) {
LogUtil.e(
"%s: Invalid url given, expected to start with 'inlinefile:', but was %s",
TAG, downloadRequest.urlToDownload());
return Futures.immediateFailedFuture(
DownloadException.builder()
.setDownloadResultCode(DownloadResultCode.INVALID_INLINE_FILE_URL_SCHEME)
.setMessage("InlineFileDownloader only supports copying inlinefile: scheme")
.build());
}
// DownloadRequest requires InlineDownloadParams to be present when building a request with
// inlinefile scheme, so we can access it directly here.
InlineDownloadParams inlineDownloadParams =
downloadRequest.inlineDownloadParamsOptional().get();
return Futures.submitAsync(
() -> {
try (InputStream inlineFileStream = getInputStream(inlineDownloadParams);
OutputStream destinationStream =
fileStorage.open(downloadRequest.fileUri(), WriteStreamOpener.create())) {
ByteStreams.copy(inlineFileStream, destinationStream);
destinationStream.flush();
} catch (IOException e) {
LogUtil.e(e, "%s: Unable to copy file content.", TAG);
return Futures.immediateFailedFuture(
DownloadException.builder()
.setCause(e)
.setDownloadResultCode(DownloadResultCode.INLINE_FILE_IO_ERROR)
.build());
}
return Futures.immediateVoidFuture();
},
downloadExecutor);
}
private InputStream getInputStream(InlineDownloadParams params) throws IOException {
switch (params.inlineFileContent().getKind()) {
case URI:
return fileStorage.open(params.inlineFileContent().uri(), ReadStreamOpener.create());
case BYTESTRING:
return params.inlineFileContent().byteString().newInput();
}
throw new IllegalStateException("unreachable");
}
}
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