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// Copyright 2014 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
package org.chromium.base;
import android.content.res.AssetFileDescriptor;
import android.content.res.AssetManager;
import android.util.Log;
import org.chromium.base.annotations.CalledByNative;
import org.chromium.base.annotations.JNINamespace;
import java.io.IOException;
/**
* A utility class to retrieve references to uncompressed assets insides the apk. A reference is
* defined as tuple (file descriptor, offset, size) enabling direct mapping without deflation.
* This can be used even within the renderer process, since it just dup's the apk's fd.
*/
@JNINamespace("base::android")
public class ApkAssets {
private static final String LOGTAG = "ApkAssets";
@CalledByNative
public static long[] open(String fileName) {
AssetFileDescriptor afd = null;
try {
AssetManager manager = ContextUtils.getApplicationContext().getAssets();
afd = manager.openNonAssetFd(fileName);
return new long[] {afd.getParcelFileDescriptor().detachFd(), afd.getStartOffset(),
afd.getLength()};
} catch (IOException e) {
// As a general rule there's no point logging here because the caller should handle
// receiving an fd of -1 sensibly, and the log message is either mirrored later, or
// unwanted (in the case where a missing file is expected), or wanted but will be
// ignored, as most non-fatal logs are.
// It makes sense to log here when the file exists, but is unable to be opened as an fd
// because (for example) it is unexpectedly compressed in an apk. In that case, the log
// message might save someone some time working out what has gone wrong.
// For that reason, we only suppress the message when the exception message doesn't look
// informative (Android framework passes the filename as the message on actual file not
// found, and the empty string also wouldn't give any useful information for debugging).
if (!e.getMessage().equals("") && !e.getMessage().equals(fileName)) {
Log.e(LOGTAG, "Error while loading asset " + fileName + ": " + e);
}
return new long[] {-1, -1, -1};
} finally {
try {
if (afd != null) {
afd.close();
}
} catch (IOException e2) {
Log.e(LOGTAG, "Unable to close AssetFileDescriptor", e2);
}
}
}
}
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