Add native DLL loader

src/main/java/org/xerial/snappy/LoadSnappy.java

@@ -0,0 +1,226 @@
+//--------------------------------------
+// snappy-java Project
+//
+// LoadSnappy.java
+// Since: 2011/03/29
+//
+// $URL$ 
+// $Author$
+//--------------------------------------
+package org.xerial.snappy;
+
+import java.io.BufferedInputStream;
+import java.io.ByteArrayOutputStream;
+import java.io.File;
+import java.io.FileInputStream;
+import java.io.FileOutputStream;
+import java.io.IOException;
+import java.io.InputStream;
+import java.net.URL;
+import java.security.DigestInputStream;
+import java.security.MessageDigest;
+import java.security.NoSuchAlgorithmException;
+import java.util.Properties;
+
+/**
+ * 
+ * 
+ * @author leo
+ * 
+ */
+public class LoadSnappy
+{
+    private static boolean extracted = false;
+
+    public static boolean initialize() {
+        if (!extracted)
+            loadSQLiteNativeLibrary();
+        return extracted;
+    }
+
+    /**
+     * Computes the MD5 value of the input stream
+     * 
+     * @param input
+     * @return
+     * @throws IOException
+     * @throws NoSuchAlgorithmException
+     */
+    static String md5sum(InputStream input) throws IOException {
+        BufferedInputStream in = new BufferedInputStream(input);
+
+        try {
+            MessageDigest digest = java.security.MessageDigest.getInstance("MD5");
+            DigestInputStream digestInputStream = new DigestInputStream(in, digest);
+            for (; digestInputStream.read() >= 0;) {
+
+            }
+            ByteArrayOutputStream md5out = new ByteArrayOutputStream();
+            md5out.write(digest.digest());
+            return md5out.toString();
+        }
+        catch (NoSuchAlgorithmException e) {
+            throw new IllegalStateException("MD5 algorithm is not available: " + e);
+        }
+        finally {
+            in.close();
+        }
+    }
+
+    /**
+     * Extract the specified library file to the target folder
+     * 
+     * @param libFolderForCurrentOS
+     * @param libraryFileName
+     * @param targetFolder
+     * @return
+     */
+    private static boolean extractAndLoadLibraryFile(String libFolderForCurrentOS, String libraryFileName,
+            String targetFolder) {
+        String nativeLibraryFilePath = libFolderForCurrentOS + "/" + libraryFileName;
+        final String prefix = "sqlite-" + getVersion() + "-";
+
+        String extractedLibFileName = prefix + libraryFileName;
+        File extractedLibFile = new File(targetFolder, extractedLibFileName);
+
+        try {
+            if (extractedLibFile.exists()) {
+                // test md5sum value
+                String md5sum1 = md5sum(LoadSnappy.class.getResourceAsStream(nativeLibraryFilePath));
+                String md5sum2 = md5sum(new FileInputStream(extractedLibFile));
+
+                if (md5sum1.equals(md5sum2)) {
+                    return loadNativeLibrary(targetFolder, extractedLibFileName);
+                }
+                else {
+                    // remove old native library file
+                    boolean deletionSucceeded = extractedLibFile.delete();
+                    if (!deletionSucceeded) {
+                        throw new IOException("failed to remove existing native library file: "
+                                + extractedLibFile.getAbsolutePath());
+                    }
+                }
+            }
+
+            // extract file into the current directory
+            InputStream reader = LoadSnappy.class.getResourceAsStream(nativeLibraryFilePath);
+            FileOutputStream writer = new FileOutputStream(extractedLibFile);
+            byte[] buffer = new byte[1024];
+            int bytesRead = 0;
+            while ((bytesRead = reader.read(buffer)) != -1) {
+                writer.write(buffer, 0, bytesRead);
+            }
+
+            writer.close();
+            reader.close();
+
+            if (!System.getProperty("os.name").contains("Windows")) {
+                try {
+                    Runtime.getRuntime().exec(new String[] { "chmod", "755", extractedLibFile.getAbsolutePath() })
+                            .waitFor();
+                }
+                catch (Throwable e) {}
+            }
+
+            return loadNativeLibrary(targetFolder, extractedLibFileName);
+        }
+        catch (IOException e) {
+            System.err.println(e.getMessage());
+            return false;
+        }
+
+    }
+
+    private static synchronized boolean loadNativeLibrary(String path, String name) {
+        File libPath = new File(path, name);
+        if (libPath.exists()) {
+
+            try {
+                System.load(new File(path, name).getAbsolutePath());
+                return true;
+            }
+            catch (UnsatisfiedLinkError e) {
+                System.err.println(e);
+                return false;
+            }
+
+        }
+        else
+            return false;
+    }
+
+    private static void loadSQLiteNativeLibrary() {
+        if (extracted)
+            return;
+
+        // Try loading library from org.sqlite.lib.path library path */
+        String sqliteNativeLibraryPath = System.getProperty("org.sqlite.lib.path");
+        String sqliteNativeLibraryName = System.getProperty("org.sqlite.lib.name");
+        if (sqliteNativeLibraryName == null)
+            sqliteNativeLibraryName = System.mapLibraryName("sqlitejdbc");
+
+        if (sqliteNativeLibraryPath != null) {
+            if (loadNativeLibrary(sqliteNativeLibraryPath, sqliteNativeLibraryName)) {
+                extracted = true;
+                return;
+            }
+        }
+
+        // Load the os-dependent library from a jar file
+        sqliteNativeLibraryPath = "/native/" + OSInfo.getNativeLibFolderPathForCurrentOS();
+
+        if (LoadSnappy.class.getResource(sqliteNativeLibraryPath + "/" + sqliteNativeLibraryName) == null) {
+            // use nested VM version
+            return;
+        }
+
+        // temporary library folder
+        String tempFolder = new File(System.getProperty("java.io.tmpdir")).getAbsolutePath();
+        // Try extracting the library from jar 
+        if (extractAndLoadLibraryFile(sqliteNativeLibraryPath, sqliteNativeLibraryName, tempFolder)) {
+            extracted = true;
+            return;
+        }
+
+        extracted = false;
+        return;
+    }
+
+    private static void getNativeLibraryFolderForTheCurrentOS() {
+        String osName = OSInfo.getOSName();
+        String archName = OSInfo.getArchName();
+
+    }
+
+    public static int getMajorVersion() {
+        String[] c = getVersion().split("\\.");
+        return (c.length > 0) ? Integer.parseInt(c[0]) : 1;
+    }
+
+    public static int getMinorVersion() {
+        String[] c = getVersion().split("\\.");
+        return (c.length > 1) ? Integer.parseInt(c[1]) : 0;
+    }
+
+    public static String getVersion() {
+
+        URL versionFile = LoadSnappy.class.getResource("/META-INF/maven/org.xerial/snappy-java/pom.properties");
+        if (versionFile == null)
+            versionFile = LoadSnappy.class.getResource("/META-INF/maven/org.xerial/snappy-java/VERSION");
+
+        String version = "unknown";
+        try {
+            if (versionFile != null) {
+                Properties versionData = new Properties();
+                versionData.load(versionFile.openStream());
+                version = versionData.getProperty("version", version);
+                version = version.trim().replaceAll("[^0-9\\.]", "");
+            }
+        }
+        catch (IOException e) {
+            System.err.println(e);
+        }
+        return version;
+    }
+
+}