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snappy-java: A fast compression/decompression library
/*--------------------------------------------------------------------------
* Copyright 2011 Taro L. Saito
*
* 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.
*--------------------------------------------------------------------------*/
//--------------------------------------
// snappy-java Project
//
// SnappyLoader.java
// Since: 2011/03/29
//
// $URL$
// $Author$
//--------------------------------------
package org.xerial.snappy;
import java.io.*;
import java.net.URL;
import java.util.Enumeration;
import java.util.Properties;
import java.util.UUID;
/**
* Internal only - Do not use this class. This class loads a native
* library of snappy-java (snappyjava.dll, libsnappy.so, etc.) according to the
* user platform (os.name and os.arch). The natively compiled
* libraries bundled to snappy-java contain the codes of the original snappy and
* JNI programs to access Snappy.
*
* In default, no configuration is required to use snappy-java, but you can load
* your own native library created by 'make native' command.
*
* This SnappyLoader searches for native libraries (snappyjava.dll,
* libsnappy.so, etc.) in the following order:
*
* - If system property org.xerial.snappy.use.systemlib is set to true,
* lookup folders specified by java.lib.path system property (This is the
* default path that JVM searches for native libraries)
*
- (System property: org.xerial.snappy.lib.path)/(System property:
* org.xerial.lib.name)
*
- One of the libraries embedded in snappy-java-(version).jar extracted into
* (System property: java.io.tempdir). If
* org.xerial.snappy.tempdir is set, use this folder instead of
* java.io.tempdir.
*
*
*
* If you do not want to use folder java.io.tempdir, set the System
* property org.xerial.snappy.tempdir. For example, to use
* /tmp/leo as a temporary folder to copy native libraries, use -D option
* of JVM:
*
*
*
* java -Dorg.xerial.snappy.tempdir="/tmp/leo" ...
*
*
*
*
*
* @author leo
*/
public class SnappyLoader
{
public static final String SNAPPY_SYSTEM_PROPERTIES_FILE = "org-xerial-snappy.properties";
public static final String KEY_SNAPPY_LIB_PATH = "org.xerial.snappy.lib.path";
public static final String KEY_SNAPPY_LIB_NAME = "org.xerial.snappy.lib.name";
public static final String KEY_SNAPPY_TEMPDIR = "org.xerial.snappy.tempdir";
public static final String KEY_SNAPPY_USE_SYSTEMLIB = "org.xerial.snappy.use.systemlib";
public static final String KEY_SNAPPY_DISABLE_BUNDLED_LIBS = "org.xerial.snappy.disable.bundled.libs"; // Depreciated, but preserved for backward compatibility
private static boolean isLoaded = false;
private static volatile SnappyNative snappyApi = null;
private static volatile BitShuffleNative bitshuffleApi = null;
private static File nativeLibFile = null;
static void cleanUpExtractedNativeLib()
{
if (nativeLibFile != null && nativeLibFile.exists()) {
boolean deleted = nativeLibFile.delete();
if (!deleted) {
// Deleting native lib has failed, but it's not serious so simply ignore it here
}
snappyApi = null;
bitshuffleApi = null;
}
}
/**
* Set the `snappyApi` instance.
*
* @param nativeCode
*/
static synchronized void setSnappyApi(SnappyNative nativeCode)
{
snappyApi = nativeCode;
}
/**
* load system properties when configuration file of the name
* {@link #SNAPPY_SYSTEM_PROPERTIES_FILE} is found
*/
private static void loadSnappySystemProperties()
{
try {
InputStream is = Thread.currentThread().getContextClassLoader()
.getResourceAsStream(SNAPPY_SYSTEM_PROPERTIES_FILE);
if (is == null) {
return; // no configuration file is found
}
// Load property file
Properties props = new Properties();
props.load(is);
is.close();
Enumeration names = props.propertyNames();
while (names.hasMoreElements()) {
String name = (String) names.nextElement();
if (name.startsWith("org.xerial.snappy.")) {
if (System.getProperty(name) == null) {
System.setProperty(name, props.getProperty(name));
}
}
}
}
catch (Throwable ex) {
System.err.println("Could not load '" + SNAPPY_SYSTEM_PROPERTIES_FILE + "' from classpath: "
+ ex.toString());
}
}
static {
loadSnappySystemProperties();
}
static synchronized SnappyNative loadSnappyApi()
{
if (snappyApi != null) {
return snappyApi;
}
loadNativeLibrary();
setSnappyApi(new SnappyNative());
return snappyApi;
}
static synchronized BitShuffleNative loadBitShuffleApi()
{
if (bitshuffleApi != null) {
return bitshuffleApi;
}
loadNativeLibrary();
bitshuffleApi = new BitShuffleNative();
return bitshuffleApi;
}
/**
* Load a native library of snappy-java
*/
private synchronized static void loadNativeLibrary()
{
if (!isLoaded) {
try {
nativeLibFile = findNativeLibrary();
if (nativeLibFile != null) {
// Load extracted or specified snappyjava native library.
System.load(nativeLibFile.getAbsolutePath());
} else {
// Load preinstalled snappyjava (in the path -Djava.library.path)
System.loadLibrary("snappyjava");
}
}
catch (Exception e) {
e.printStackTrace();
throw new SnappyError(SnappyErrorCode.FAILED_TO_LOAD_NATIVE_LIBRARY, e.getMessage());
}
isLoaded = true;
}
}
private static boolean contentsEquals(InputStream in1, InputStream in2)
throws IOException
{
if (!(in1 instanceof BufferedInputStream)) {
in1 = new BufferedInputStream(in1);
}
if (!(in2 instanceof BufferedInputStream)) {
in2 = new BufferedInputStream(in2);
}
int ch = in1.read();
while (ch != -1) {
int ch2 = in2.read();
if (ch != ch2) {
return false;
}
ch = in1.read();
}
int ch2 = in2.read();
return ch2 == -1;
}
/**
* Extract the specified library file to the target folder
*
* @param libFolderForCurrentOS
* @param libraryFileName
* @param targetFolder
* @return
*/
private static File extractLibraryFile(String libFolderForCurrentOS, String libraryFileName, String targetFolder)
{
String nativeLibraryFilePath = libFolderForCurrentOS + "/" + libraryFileName;
// Attach UUID to the native library file to ensure multiple class loaders can read the libsnappy-java multiple times.
String uuid = UUID.randomUUID().toString();
String extractedLibFileName = String.format("snappy-%s-%s-%s", getVersion(), uuid, libraryFileName);
File extractedLibFile = new File(targetFolder, extractedLibFileName);
try {
// Extract a native library file into the target directory
InputStream reader = null;
FileOutputStream writer = null;
try {
reader = SnappyLoader.class.getResourceAsStream(nativeLibraryFilePath);
try {
writer = new FileOutputStream(extractedLibFile);
byte[] buffer = new byte[8192];
int bytesRead = 0;
while ((bytesRead = reader.read(buffer)) != -1) {
writer.write(buffer, 0, bytesRead);
}
}
finally {
if (writer != null) {
writer.close();
}
}
}
finally {
if (reader != null) {
reader.close();
}
// Delete the extracted lib file on JVM exit.
extractedLibFile.deleteOnExit();
}
// Set executable (x) flag to enable Java to load the native library
boolean success = extractedLibFile.setReadable(true) &&
extractedLibFile.setWritable(true, true) &&
extractedLibFile.setExecutable(true);
if (!success) {
// Setting file flag may fail, but in this case another error will be thrown in later phase
}
// Check whether the contents are properly copied from the resource folder
{
InputStream nativeIn = null;
InputStream extractedLibIn = null;
try {
nativeIn = SnappyLoader.class.getResourceAsStream(nativeLibraryFilePath);
extractedLibIn = new FileInputStream(extractedLibFile);
if (!contentsEquals(nativeIn, extractedLibIn)) {
throw new SnappyError(SnappyErrorCode.FAILED_TO_LOAD_NATIVE_LIBRARY, String.format("Failed to write a native library file at %s", extractedLibFile));
}
}
finally {
if (nativeIn != null) {
nativeIn.close();
}
if (extractedLibIn != null) {
extractedLibIn.close();
}
}
}
return new File(targetFolder, extractedLibFileName);
}
catch (IOException e) {
e.printStackTrace(System.err);
return null;
}
}
static File findNativeLibrary()
{
boolean useSystemLib = Boolean.parseBoolean(System.getProperty(KEY_SNAPPY_USE_SYSTEMLIB, "false"));
boolean disabledBundledLibs = Boolean
.parseBoolean(System.getProperty(KEY_SNAPPY_DISABLE_BUNDLED_LIBS, "false"));
if (useSystemLib || disabledBundledLibs) {
return null; // Use a pre-installed libsnappyjava
}
// Try to load the library in org.xerial.snappy.lib.path */
String snappyNativeLibraryPath = System.getProperty(KEY_SNAPPY_LIB_PATH);
String snappyNativeLibraryName = System.getProperty(KEY_SNAPPY_LIB_NAME);
// Resolve the library file name with a suffix (e.g., dll, .so, etc.)
if (snappyNativeLibraryName == null) {
snappyNativeLibraryName = System.mapLibraryName("snappyjava");
}
if (snappyNativeLibraryPath != null) {
File nativeLib = new File(snappyNativeLibraryPath, snappyNativeLibraryName);
if (nativeLib.exists()) {
return nativeLib;
}
}
// Load an OS-dependent native library inside a jar file
snappyNativeLibraryPath = "/org/xerial/snappy/native/" + OSInfo.getNativeLibFolderPathForCurrentOS();
boolean hasNativeLib = hasResource(snappyNativeLibraryPath + "/" + snappyNativeLibraryName);
if (!hasNativeLib) {
if (OSInfo.getOSName().equals("Mac")) {
// Fix for openjdk7 for Mac
String altName = "libsnappyjava.jnilib";
if (hasResource(snappyNativeLibraryPath + "/" + altName)) {
snappyNativeLibraryName = altName;
hasNativeLib = true;
}
}
}
if (!hasNativeLib) {
String errorMessage = String.format("no native library is found for os.name=%s and os.arch=%s", OSInfo.getOSName(), OSInfo.getArchName());
throw new SnappyError(SnappyErrorCode.FAILED_TO_LOAD_NATIVE_LIBRARY, errorMessage);
}
// Temporary folder for the native lib. Use the value of org.xerial.snappy.tempdir or java.io.tmpdir
File tempFolder = new File(System.getProperty(KEY_SNAPPY_TEMPDIR, System.getProperty("java.io.tmpdir")));
if (!tempFolder.exists()) {
boolean created = tempFolder.mkdirs();
if (!created) {
// if created == false, it will fail eventually in the later part
}
}
// Extract and load a native library inside the jar file
return extractLibraryFile(snappyNativeLibraryPath, snappyNativeLibraryName, tempFolder.getAbsolutePath());
}
private static boolean hasResource(String path)
{
return SnappyLoader.class.getResource(path) != null;
}
/**
* Get the snappy-java version by reading pom.properties embedded in jar.
* This version data is used as a suffix of a dll file extracted from the
* jar.
*
* @return the version string
*/
public static String getVersion()
{
URL versionFile = SnappyLoader.class
.getResource("/META-INF/maven/org.xerial.snappy/snappy-java/pom.properties");
if (versionFile == null) {
versionFile = SnappyLoader.class.getResource("/org/xerial/snappy/VERSION");
}
String version = "unknown";
try {
if (versionFile != null) {
Properties versionData = new Properties();
versionData.load(versionFile.openStream());
version = versionData.getProperty("version", version);
if (version.equals("unknown")) {
version = versionData.getProperty("SNAPPY_VERSION", version);
}
version = version.trim().replaceAll("[^0-9M\\.]", "");
}
}
catch (IOException e) {
System.err.println(e);
}
return version;
}
}
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