blob: aa7d38c69e6d04e0729294cef794ced035958b85 [file] [log] [blame]
/*
* 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.file.openers;
import android.net.Uri;
import android.util.Pair;
import com.google.android.libraries.mobiledatadownload.file.OpenContext;
import com.google.android.libraries.mobiledatadownload.file.Opener;
import java.io.Closeable;
import java.io.IOException;
/**
* An opener that produces a file descriptor URI (like "fd:123"). This is useful for opening a file
* in Java and passing a handle to it down to C++.
*
* <p>Transforms are not applied in the Java code and are retained in the returned URI so they can
* be applied in native code.
*
* <p>The caller is responsible for closing the file descriptor. The native code is expected to dup
* the descriptor if it needs to hold it, so they can both call close independently.
*
* <p>Usage: <code>
* try (CloseableUri fdUri = storage.open(uri, NativeReadOpener.create())) {
* // Use URI in native code
* }
* </code>
*/
public final class NativeReadOpener implements Opener<CloseableUri> {
private NativeReadOpener() {}
public static NativeReadOpener create() {
return new NativeReadOpener();
}
@Override
public CloseableUri open(OpenContext openContext) throws IOException {
Pair<Uri, Closeable> result = openContext.backend().openForNativeRead(openContext.encodedUri());
Uri uriWithFragment =
result
.first
.buildUpon()
.encodedFragment(openContext.originalUri().getEncodedFragment())
.build();
return new CloseableUri() {
@Override
public Uri uri() {
return uriWithFragment;
}
@Override
public void close() throws IOException {
result.second.close();
}
};
}
}