From b914b123a68500187b3f8a72fcf53be9687d66f0 Mon Sep 17 00:00:00 2001
From: brinn <brinn>
Date: Tue, 1 Jul 2008 21:14:31 +0000
Subject: [PATCH] add: - support for getting link information - new native
libraries, also for Solaris
SVN: 6965
---
.../common/utilities/FileLinkUtilities.java | 162 ++++++++++++++++--
1 file changed, 151 insertions(+), 11 deletions(-)
diff --git a/common/source/java/ch/systemsx/cisd/common/utilities/FileLinkUtilities.java b/common/source/java/ch/systemsx/cisd/common/utilities/FileLinkUtilities.java
index a07b4809b11..aa9e2bbfa64 100644
--- a/common/source/java/ch/systemsx/cisd/common/utilities/FileLinkUtilities.java
+++ b/common/source/java/ch/systemsx/cisd/common/utilities/FileLinkUtilities.java
@@ -38,6 +38,71 @@ public class FileLinkUtilities
}
}
+ /** An exception that indicates that obtaining information about a link failed. */
+ public static final class FileLinkInfoException extends RuntimeException
+ {
+ private static final long serialVersionUID = 1L;
+
+ private FileLinkInfoException(String filename, String errorMessage)
+ {
+ super(String.format("Cannot obtain inode info for file '%s': %s", filename,
+ errorMessage));
+ }
+ }
+
+ /** A class that provides information about a link. */
+ public static final class LinkInfo
+ {
+ private final int inode;
+
+ private final int hardLinkCount;
+
+ private final boolean isSsymbolicLink;
+
+ private final String symbolicLinkOrNull;
+
+ private LinkInfo(int[] info, String symbolicLinkOrNull)
+ {
+ this.inode = info[0];
+ this.hardLinkCount = info[1];
+ this.isSsymbolicLink = (info[2] != 0);
+ this.symbolicLinkOrNull = symbolicLinkOrNull;
+ }
+
+ /**
+ * Returns <code>true</code>, if this link is a symbolic link.
+ */
+ public final boolean isSymbolicLink()
+ {
+ return isSsymbolicLink;
+ }
+
+ /**
+ * Returns the value of the symbolic link, or <code>null</code>, if this link is not a
+ * symbolic link.
+ */
+ public final String tryGetSymbolicLink()
+ {
+ return symbolicLinkOrNull;
+ }
+
+ /**
+ * Returns the inode number of this link.
+ */
+ public final int getInode()
+ {
+ return inode;
+ }
+
+ /**
+ * Returns the hard link count of this link.
+ */
+ public final int getHardLinkCount()
+ {
+ return hardLinkCount;
+ }
+ }
+
//
// The wrappers for the native function calls.
//
@@ -46,6 +111,10 @@ public class FileLinkUtilities
private static native int symlink(String filename, String linktarget);
+ private static native int linkinfo(String filename, int[] info);
+
+ private static native String readlink(String filename, int linkvallen);
+
private static native String strerror(int errnum);
/**
@@ -58,35 +127,106 @@ public class FileLinkUtilities
}
/**
- * Creates a hard link from <var>filename</var> to <var>linktarget</var>.
+ * Creates a hard link from <var>filename</var> to <var>linkname</var>.
*
* @throws FileLinkException If the underlying system call fails, e.g. because <var>filename</var>
- * does not exist or because <var>linktarget</var> already exists.
+ * does not exist or because <var>linkname</var> already exists.
*/
- public static final void createHardLink(String filename, String linktarget)
+ public static final void createHardLink(String filename, String linkname)
throws FileLinkException
{
- final int result = hardlink(filename, linktarget);
- if (result != 0)
+ final int result = hardlink(filename, linkname);
+ if (result < 0)
{
- throw new FileLinkException("hard", linktarget, filename, strerror(result));
+ throw new FileLinkException("hard", linkname, filename, strerror(result));
}
}
/**
- * Creates a symbolic link from <var>filename</var> to <var>linktarget</var>.
+ * Creates a symbolic link from <var>filename</var> to <var>linkname</var>.
*
* @throws FileLinkException If the underlying system call fails, e.g. because <var>filename</var>
* does not exist or because <var>linktarget</var> already exists.
*/
- public static final void createSymbolicLink(String filename, String linktarget)
+ public static final void createSymbolicLink(String filename, String linkname)
throws FileLinkException
{
- final int result = symlink(filename, linktarget);
- if (result != 0)
+ final int result = symlink(filename, linkname);
+ if (result < 0)
{
- throw new FileLinkException("symbolic", linktarget, filename, strerror(result));
+ throw new FileLinkException("symbolic", linkname, filename, strerror(result));
}
}
+ private static int[] getLinkInfoArray(String linkname) throws FileLinkInfoException
+ {
+ final int[] inodeInfo = new int[4];
+ final int result = linkinfo(linkname, inodeInfo);
+ if (result < 0)
+ {
+ throw new FileLinkInfoException(linkname, strerror(result));
+ }
+ return inodeInfo;
+ }
+
+ /**
+ * Returns the inode for the <var>filename</var>.
+ *
+ * @throws FileLinkInfoException If the information could not be obtained, e.g. because the link
+ * does not exist.
+ */
+ public static final int getInode(String filename) throws FileLinkInfoException
+ {
+ return getLinkInfoArray(filename)[0];
+ }
+
+ /**
+ * Returns the inode for the <var>filename</var>.
+ *
+ * @throws FileLinkInfoException If the information could not be obtained, e.g. because the link
+ * does not exist.
+ */
+ public static final int getHardLinkCount(String filename) throws FileLinkInfoException
+ {
+ return getLinkInfoArray(filename)[1];
+ }
+
+ /**
+ * Returns <code>true</code> if <var>filename</var> is a symbolic link and <code>false</code>
+ * otherwise.
+ *
+ * @throws FileLinkInfoException If the information could not be obtained, e.g. because the link
+ * does not exist.
+ */
+ public static final boolean isSymbolicLink(String filename) throws FileLinkInfoException
+ {
+ return getLinkInfoArray(filename)[2] != 0;
+ }
+
+ /**
+ * Returns the value of the symbolik link <var>filename</var>, or <code>null</code>, if
+ * <var>filename</var> is not a symbolic link.
+ *
+ * @throws FileLinkInfoException If the information could not be obtained, e.g. because the link
+ * does not exist.
+ */
+ public static final String tryReadSymbolicLink(String linkname) throws FileLinkInfoException
+ {
+ final int[] info = getLinkInfoArray(linkname);
+ return (info[2] != 0) ? readlink(linkname, info[3]) : null;
+ }
+
+ /**
+ * Returns the information about <var>linkname</var>.
+ *
+ * @throws FileLinkInfoException If the information could not be obtained, e.g. because the link
+ * does not exist.
+ */
+ public static final LinkInfo getLinkInfo(String linkname) throws FileLinkInfoException
+ {
+ final int[] info = getLinkInfoArray(linkname);
+ final String symbolicLinkOrNull = (info[2] != 0) ? readlink(linkname, info[3]) : null;
+ return new LinkInfo(info, symbolicLinkOrNull);
+ }
+
}
--
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