/*
* This file is part of the Heritrix web crawler (crawler.archive.org).
*
* Licensed to the Internet Archive (IA) by one or more individual
* contributors.
*
* The IA licenses this file to You 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 org.archive.io.arc;
import it.unimi.dsi.fastutil.io.RepositionableStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStream;
import java.net.URI;
import java.net.URISyntaxException;
import org.archive.url.UsableURI;
import org.archive.util.zip.GzipHeader;
import org.archive.util.zip.NoGzipMagicException;
public class ARCUtils implements ARCConstants {
/**
* @param pathOrUri Path or URI to extract arc filename from.
* @return Extracted arc file name.
* @throws URISyntaxException
*/
public static String parseArcFilename(final String pathOrUri)
throws URISyntaxException {
String path = pathOrUri;
if (UsableURI.hasScheme(pathOrUri)) {
URI url = new URI(pathOrUri);
path = url.getPath();
}
return (new File(path)).getName();
}
/**
* @param arcFile File to test.
* @return True if <code>arcFile</code> is compressed ARC.
* @throws IOException
*/
public static boolean isCompressed(File arcFile) throws IOException {
return testCompressedARCFile(arcFile);
}
/**
* Check file is compressed and in ARC GZIP format.
*
* @param arcFile File to test if its Internet Archive ARC file
* GZIP compressed.
*
* @return True if this is an Internet Archive GZIP'd ARC file (It begins
* w/ the Internet Archive GZIP header and has the
* COMPRESSED_ARC_FILE_EXTENSION suffix).
*
* @exception IOException If file does not exist or is not unreadable.
*/
public static boolean testCompressedARCFile(File arcFile)
throws IOException {
return testCompressedARCFile(arcFile, false);
}
/**
* Check file is compressed and in ARC GZIP format.
*
* @param arcFile File to test if its Internet Archive ARC file
* GZIP compressed.
* @param skipSuffixCheck Set to true if we're not to test on the
* '.arc.gz' suffix.
*
* @return True if this is an Internet Archive GZIP'd ARC file (It begins
* w/ the Internet Archive GZIP header).
*
* @exception IOException If file does not exist or is not unreadable.
*/
public static boolean testCompressedARCFile(File arcFile,
boolean skipSuffixCheck)
throws IOException {
boolean compressedARCFile = false;
isReadable(arcFile);
if(!skipSuffixCheck && !arcFile.getName().toLowerCase()
.endsWith(COMPRESSED_ARC_FILE_EXTENSION)) {
return compressedARCFile;
}
final InputStream is = new FileInputStream(arcFile);
try {
compressedARCFile = testCompressedARCStream(is);
} finally {
is.close();
}
return compressedARCFile;
}
/**
* Tests passed stream is gzip stream by reading in the HEAD.
* Does not reposition the stream. That is left up to the caller.
* @param is An InputStream.
* @return True if compressed stream.
* @throws IOException
*/
public static boolean testCompressedARCStream(final InputStream is)
throws IOException {
boolean compressedARCFile = false;
GzipHeader gh = null;
try {
gh = new GzipHeader(is);
} catch (NoGzipMagicException e ) {
return compressedARCFile;
}
byte[] fextra = gh.getFextra();
// Now make sure following bytes are IA GZIP comment.
// First check length. ARC_GZIP_EXTRA_FIELD includes length
// so subtract two and start compare to ARC_GZIP_EXTRA_FIELD
// at +2.
if (fextra != null &&
ARC_GZIP_EXTRA_FIELD.length - 2 == fextra.length) {
compressedARCFile = true;
for (int i = 0; i < fextra.length; i++) {
if (fextra[i] != ARC_GZIP_EXTRA_FIELD[i + 2]) {
compressedARCFile = false;
break;
}
}
}
return compressedARCFile;
}
/**
* Tests passed stream is gzip stream by reading in the HEAD.
* Does reposition of stream when done.
* @param rs An InputStream that is Repositionable.
* @return True if compressed stream.
* @throws IOException
*/
public static boolean testCompressedRepositionalStream(
final RepositionableStream rs)
throws IOException {
boolean compressedARCFile = false;
long p = rs.position();
try {
compressedARCFile = testCompressedStream((InputStream)rs);
} finally {
rs.position(p);
}
return compressedARCFile;
}
/**
* Tests passed stream is gzip stream by reading in the HEAD.
* Does reposition of stream when done.
* @param is An InputStream.
* @return True if compressed stream.
* @throws IOException
*/
public static boolean testCompressedStream(final InputStream is)
throws IOException {
boolean compressedARCFile = false;
try {
new GzipHeader(is);
compressedARCFile = true;
} catch (NoGzipMagicException e) {
return compressedARCFile;
}
return compressedARCFile;
}
/**
* Check file is uncompressed ARC file.
*
* @param arcFile
* File to test if its Internet Archive ARC file uncompressed.
*
* @return True if this is an Internet Archive ARC file.
*
* @exception IOException
* If file does not exist or is not unreadable.
*/
public static boolean testUncompressedARCFile(File arcFile)
throws IOException {
boolean uncompressedARCFile = false;
isReadable(arcFile);
if(arcFile.getName().toLowerCase().endsWith(ARC_FILE_EXTENSION)) {
FileInputStream fis = new FileInputStream(arcFile);
try {
byte [] b = new byte[ARC_MAGIC_NUMBER.length()];
int read = fis.read(b, 0, ARC_MAGIC_NUMBER.length());
fis.close();
if (read == ARC_MAGIC_NUMBER.length()) {
StringBuffer beginStr
= new StringBuffer(ARC_MAGIC_NUMBER.length());
for (int i = 0; i < ARC_MAGIC_NUMBER.length(); i++) {
beginStr.append((char)b[i]);
}
if (beginStr.toString().
equalsIgnoreCase(ARC_MAGIC_NUMBER)) {
uncompressedARCFile = true;
}
}
} finally {
fis.close();
}
}
return uncompressedARCFile;
}
/**
* @param arcFile File to test.
* @exception IOException If file does not exist or is not unreadable.
*/
private static void isReadable(File arcFile) throws IOException {
if (!arcFile.exists()) {
throw new FileNotFoundException(arcFile.getAbsolutePath() +
" does not exist.");
}
if (!arcFile.canRead()) {
throw new FileNotFoundException(arcFile.getAbsolutePath() +
" is not readable.");
}
}
}