From 35f55ae7e034275811fa68908215b48bbf9df965 Mon Sep 17 00:00:00 2001
From: James Moger <james.moger@gitblit.com>
Date: Tue, 17 Sep 2013 17:05:00 -0400
Subject: [PATCH] Merge branch 'init-shared' of https://github.com/fzs/gitblit into prefixes

---
 src/main/java/com/gitblit/utils/JnaUtils.java |  364 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 files changed, 364 insertions(+), 0 deletions(-)

diff --git a/src/main/java/com/gitblit/utils/JnaUtils.java b/src/main/java/com/gitblit/utils/JnaUtils.java
new file mode 100644
index 0000000..4009342
--- /dev/null
+++ b/src/main/java/com/gitblit/utils/JnaUtils.java
@@ -0,0 +1,364 @@
+/*
+ * Copyright 2013 gitblit.com.
+ *
+ * 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.gitblit.utils;
+
+import com.sun.jna.Library;
+import com.sun.jna.Native;
+
+import java.io.BufferedReader;
+import java.io.File;
+import java.io.IOException;
+import java.io.InputStreamReader;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+/**
+ * Collection of static methods to access native OS library functionality.
+ *
+ * @author Florian Zschocke
+ */
+public class JnaUtils {
+	public static final int S_ISUID =  0004000; // set user id on execution
+	public static final int S_ISGID =  0002000; // set group id on execution
+	public static final int S_ISVTX =  0001000; // sticky bit, save swapped text even after use
+
+	public static final int S_IRWXU =  0000700; // RWX mask for owner
+	public static final int S_IRUSR =  0000400; // read permission for owner
+	public static final int S_IWUSR =  0000200; // write permission for owner
+	public static final int S_IXUSR =  0000100; // execute/search permission for owner
+	public static final int S_IRWXG =  0000070; // RWX mask for group
+	public static final int S_IRGRP =  0000040; // read permission for group
+	public static final int S_IWGRP =  0000020; // write permission for group
+	public static final int S_IXGRP =  0000010; // execute/search permission for group
+	public static final int S_IRWXO =  0000007; // RWX mask for other
+	public static final int S_IROTH =  0000004; // read permission for other
+	public static final int S_IWOTH =  0000002; // write permission for other
+	public static final int S_IXOTH =  0000001; // execute/search permission for other
+
+	public static final int S_IFMT =   0170000; // type of file mask
+	public static final int S_IFIFO =  0010000; // named pipe (fifo)
+	public static final int S_IFCHR =  0020000; // character special device
+	public static final int S_IFDIR =  0040000; // directory
+	public static final int S_IFBLK =  0060000; // block special device
+	public static final int S_IFREG =  0100000; // regular file
+	public static final int S_IFLNK =  0120000; // symbolic link
+	public static final int S_IFSOCK = 0140000; // socket
+
+
+	private static final Logger LOGGER = LoggerFactory.getLogger(JGitUtils.class);
+
+	private static UnixCLibrary unixlibc = null;
+
+
+	/**
+	 * Utility method to check if the JVM is running on a Windows OS.
+	 *
+	 * @return true, if the system property 'os.name' starts with 'Windows'.
+	 */
+	public static boolean isWindows()
+	{
+		return System.getProperty("os.name").toLowerCase().startsWith("windows");
+	}
+
+
+	private interface UnixCLibrary extends Library {
+		public int chmod(String path, int mode);
+		public int getgid();
+		public int getegid();
+	}
+
+
+	public static int getgid()
+	{
+		if (isWindows()) {
+			throw new UnsupportedOperationException("The method JnaUtils.getgid is not supported under Windows.");
+		}
+
+		return getUnixCLibrary().getgid();
+	}
+
+
+	public static int getegid()
+	{
+		if (isWindows()) {
+			throw new UnsupportedOperationException("The method JnaUtils.getegid is not supported under Windows.");
+		}
+
+		return getUnixCLibrary().getegid();
+	}
+
+
+	/**
+	 * Set the permission bits of a file.
+	 *
+	 * The permission bits are set to the provided mode. This method is only
+	 * implemented for OSes of the Unix family and makes use of the 'chmod'
+	 * function of the native C library. See 'man 2 chmod' for more information.
+	 *
+	 * @param path
+	 * 			File/directory to set the permission bits for.
+	 * @param mode
+	 * 			A mode created from or'd permission bit masks S_I*
+	 * @return	Upon successful completion, a value of 0 returned. Otherwise, a value of -1 is returned.
+	 */
+	public static int setFilemode(File file, int mode)
+	{
+		return setFilemode(file.getAbsolutePath(), mode);
+	}
+
+	/**
+	 * Set the permission bits of a file.
+	 *
+	 * The permission bits are set to the provided mode. This method is only
+	 * implemented for OSes of the Unix family and makes use of the 'chmod'
+	 * function of the native C library. See 'man 2 chmod' for more information.
+	 *
+	 * @param path
+	 * 			Path to a file/directory to set the permission bits for.
+	 * @param mode
+	 * 			A mode created from or'd permission bit masks S_I*
+	 * @return	Upon successful completion, a value of 0 returned. Otherwise, a value of -1 is returned.
+	 */
+	public static int setFilemode(String path, int mode)
+	{
+		if (isWindows()) {
+			throw new UnsupportedOperationException("The method JnaUtils.getFilemode is not supported under Windows.");
+		}
+
+		return getUnixCLibrary().chmod(path, mode);
+	}
+
+
+
+	/**
+	 * Get the file mode bits of a file.
+	 *
+	 * This method is only implemented for OSes of the Unix family. It returns the file mode
+	 * information as available in the st_mode member of the resulting struct stat when calling
+	 * 'lstat' on a file.
+	 *
+	 * @param path
+	 * 			File/directory to get the file mode from.
+	 * @return	Upon successful completion, the file mode bits are returned. Otherwise, a value of -1 is returned.
+	 */
+	public static int getFilemode(File path)
+	{
+		return getFilemode(path.getAbsolutePath());
+	}
+
+	/**
+	 * Get the file mode bits of a file.
+	 *
+	 * This method is only implemented for OSes of the Unix family. It returns the file mode
+	 * information as available in the st_mode member of the resulting struct stat when calling
+	 * 'lstat' on a file.
+	 *
+	 * @param path
+	 * 			Path to a file/directory to get the file mode from.
+	 * @return	Upon successful completion, the file mode bits are returned. Otherwise, a value of -1 is returned.
+	 */
+	public static int getFilemode(String path)
+	{
+		if (isWindows()) {
+			throw new UnsupportedOperationException("The method JnaUtils.getFilemode is not supported under Windows.");
+		}
+
+		Filestat stat = getFilestat(path);
+		if ( stat == null ) return -1;
+		return stat.mode;
+	}
+
+
+	/**
+	 * Status information of a file.
+	 */
+	public static class Filestat
+	{
+		public int mode;  // file mode, permissions, type
+		public int uid;   // user Id of owner
+		public int gid;   // group Id of owner
+
+		Filestat(int mode, int uid, int gid) {
+			this.mode = mode; this.uid = uid; this.gid = gid;
+		}
+	}
+
+
+	/**
+	 * Get Unix file status information for a file.
+	 *
+	 * This method is only implemented for OSes of the Unix family. It returns file status
+	 * information for a file. Currently this is the file mode, the user id and group id of the owner.
+	 *
+	 * @param path
+	 * 			File/directory to get the file status from.
+	 * @return	Upon successful completion, a Filestat object containing the file information is returned.
+	 * 			Otherwise, null is returned.
+	 */
+	public static Filestat getFilestat(File path)
+	{
+		return getFilestat(path.getAbsolutePath());
+	}
+
+
+	/**
+	 * Get Unix file status information for a file.
+	 *
+	 * This method is only implemented for OSes of the Unix family. It returns file status
+	 * information for a file. Currently this is the file mode, the user id and group id of the owner.
+	 *
+	 * @param path
+	 * 			Path to a file/directory to get the file status from.
+	 * @return	Upon successful completion, a Filestat object containing the file information is returned.
+	 * 			Otherwise, null is returned.
+	 */
+	public static Filestat getFilestat(String path)
+	{
+		if (isWindows()) {
+			throw new UnsupportedOperationException("The method JnaUtils.getFilestat is not supported under Windows.");
+		}
+
+
+		int mode = 0;
+
+		// Use a Runtime, because implementing stat() via JNA is just too much trouble.
+		// This could be done with the 'stat' command, too. But that may have a shell specific implementation, so we use 'ls' instead.
+		String lsLine = runProcessLs(path);
+		if (lsLine == null) {
+			LOGGER.debug("Could not get file information for path " + path);
+			return null;
+		}
+
+		Pattern p = Pattern.compile("^(([-bcdlspCDMnP?])([-r][-w][-xSs])([-r][-w][-xSs])([-r][-w][-xTt]))[@+.]? +[0-9]+ +([0-9]+) +([0-9]+) ");
+		Matcher m = p.matcher(lsLine);
+		if ( !m.lookingAt() ) {
+			LOGGER.debug("Could not parse valid file mode information for path " + path);
+			return null;
+		}
+
+		// Parse mode string to mode bits
+		String group = m.group(2);
+		switch (group.charAt(0)) {
+		case 'p' :
+			mode |= 0010000; break;
+		case 'c':
+			mode |= 0020000; break;
+		case 'd':
+			mode |= 0040000; break;
+		case 'b':
+			mode |= 0060000; break;
+		case '-':
+			mode |= 0100000; break;
+		case 'l':
+			mode |= 0120000; break;
+		case 's':
+			mode |= 0140000; break;
+		}
+
+		for ( int i = 0; i < 3; i++) {
+			group = m.group(3 + i);
+			switch (group.charAt(0)) {
+			case 'r':
+				mode |= (0400 >> i*3); break;
+			case '-':
+				break;
+			}
+
+			switch (group.charAt(1)) {
+			case 'w':
+				mode |= (0200 >> i*3); break;
+			case '-':
+				break;
+			}
+
+			switch (group.charAt(2)) {
+			case 'x':
+				mode |= (0100 >> i*3); break;
+			case 'S':
+				mode |= (04000 >> i); break;
+			case 's':
+				mode |= (0100 >> i*3);
+				mode |= (04000 >> i); break;
+			case 'T':
+				mode |= 01000; break;
+			case 't':
+				mode |= (0100 >> i*3);
+				mode |= 01000; break;
+			case '-':
+				break;
+			}
+		}
+
+		return new Filestat(mode, Integer.parseInt(m.group(6)), Integer.parseInt(m.group(7)));
+	}
+
+
+	/**
+	 * Run the unix command 'ls -ldn' on a single file and return the resulting output line.
+	 *
+	 * @param path
+	 * 			Path to a single file or directory.
+	 * @return The first line of output from the 'ls' command. Null, if an error occurred and no line could be read.
+	 */
+	private static String runProcessLs(String path)
+	{
+		String cmd = "ls -ldn " + path;
+		Runtime rt = Runtime.getRuntime();
+		Process pr = null;
+		InputStreamReader ir = null;
+		BufferedReader br = null;
+		String output = null;
+
+		try {
+			pr = rt.exec(cmd);
+			ir = new InputStreamReader(pr.getInputStream());
+			br = new BufferedReader(ir);
+
+			output = br.readLine();
+
+			while (br.readLine() != null) ; // Swallow remaining output
+		}
+		catch (IOException e) {
+			LOGGER.debug("Exception while running unix command '" + cmd + "': " + e);
+		}
+		finally {
+			if (pr != null) try { pr.waitFor();	} catch (Exception ignored) {}
+
+			if (br != null) try { br.close(); } catch (Exception ignored) {}
+			if (ir != null) try { ir.close(); } catch (Exception ignored) {}
+
+			if (pr != null) try { pr.getOutputStream().close();	} catch (Exception ignored) {}
+			if (pr != null) try { pr.getInputStream().close();	} catch (Exception ignored) {}
+			if (pr != null) try { pr.getErrorStream().close();	} catch (Exception ignored) {}
+		}
+
+		return output;
+	}
+
+
+	private static UnixCLibrary getUnixCLibrary()
+	{
+		if (unixlibc == null) {
+			unixlibc = (UnixCLibrary) Native.loadLibrary("c", UnixCLibrary.class);
+			if (unixlibc == null) throw new RuntimeException("Could not initialize native C library.");
+		}
+		return unixlibc;
+	}
+
+}

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