* TarEntries that are created from the header bytes read from * an archive are instantiated with the TarEntry( byte[] ) * constructor. These entries will be used when extracting from * or listing the contents of an archive. These entries have their * header filled in using the header bytes. They also set the File * to null, since they reference an archive entry not a file. *
* TarEntries that are created from Files that are to be written * into an archive are instantiated with the TarEntry( File ) * constructor. These entries have their header filled in using * the File's information. They also keep a reference to the File * for convenience when writing entries. *
* Finally, TarEntries can be constructed from nothing but a name. * This allows the programmer to construct the entry by hand, for * instance when only an InputStream is available for writing to * the archive, and the header information is constructed from * other information. In this case the header fields are set to * defaults and the File is set to null. * *
* The C structure for a Tar Entry's header is: *
* struct header {
* char name[NAMSIZ];
* char mode[8];
* char uid[8];
* char gid[8];
* char size[12];
* char mtime[12];
* char chksum[8];
* char linkflag;
* char linkname[NAMSIZ];
* char magic[8];
* char uname[TUNMLEN];
* char gname[TGNMLEN];
* char devmajor[8];
* char devminor[8];
* } header;
*
*
*/
public class TarEntry implements TarConstants {
/** The entry's name. */
private StringBuilder name;
/** The entry's permission mode. */
private int mode;
/** The entry's user id. */
private int userId;
/** The entry's group id. */
private int groupId;
/** The entry's size. */
private long size;
/** The entry's modification time. */
private long modTime;
/** The entry's link flag. */
private byte linkFlag;
/** The entry's link name. */
private StringBuilder linkName;
/** The entry's magic tag. */
private StringBuilder magic;
/** The entry's user name. */
private StringBuilder userName;
/** The entry's group name. */
private StringBuilder groupName;
/** The entry's major device number. */
private int devMajor;
/** The entry's minor device number. */
private int devMinor;
/** The entry's file reference */
private File file;
/** Maximum length of a user's name in the tar file */
public static final int MAX_NAMELEN = 31;
/** Default permissions bits for directories */
public static final int DEFAULT_DIR_MODE = 040755;
/** Default permissions bits for files */
public static final int DEFAULT_FILE_MODE = 0100644;
/** Convert millis to seconds */
public static final int MILLIS_PER_SECOND = 1000;
/**
* Construct an empty entry and prepares the header values.
*/
private TarEntry () {
this.magic = new StringBuilder(TMAGIC);
this.name = new StringBuilder();
this.linkName = new StringBuilder();
String user = System.getProperty("user.name", "");
if (user.length() > MAX_NAMELEN) {
user = user.substring(0, MAX_NAMELEN);
}
this.userId = 0;
this.groupId = 0;
this.userName = new StringBuilder(user);
this.groupName = new StringBuilder("");
this.file = null;
}
/**
* Construct an entry with only a name. This allows the programmer
* to construct the entry's header "by hand". File is set to null.
*
* @param name the entry name
*/
public TarEntry(final String name) {
this();
final boolean isDir = name.endsWith("/");
this.devMajor = 0;
this.devMinor = 0;
this.name = new StringBuilder(name);
this.mode = isDir ? DEFAULT_DIR_MODE : DEFAULT_FILE_MODE;
this.linkFlag = isDir ? LF_DIR : LF_NORMAL;
this.userId = 0;
this.groupId = 0;
this.size = 0;
this.modTime = (new Date()).getTime() / MILLIS_PER_SECOND;
this.linkName = new StringBuilder("");
this.userName = new StringBuilder("");
this.groupName = new StringBuilder("");
this.devMajor = 0;
this.devMinor = 0;
}
/**
* Construct an entry with a name an a link flag.
*
* @param name the entry name
* @param linkFlag the entry link flag.
*/
public TarEntry(final String name, final byte linkFlag) {
this(name);
this.linkFlag = linkFlag;
}
/**
* Construct an entry for a file. File is set to file, and the
* header is constructed from information from the file.
*
* @param file The file that the entry represents.
*/
public TarEntry(final File file) {
this();
this.file = file;
String fileName = file.getPath();
final String osname = System.getProperty("os.name").toLowerCase(Locale.US);
if (osname != null) {
// Strip off drive letters!
// REVIEW Would a better check be "(File.separator == '\')"?
if (osname.startsWith("windows")) {
if (fileName.length() > 2) {
final char ch1 = fileName.charAt(0);
final char ch2 = fileName.charAt(1);
if (ch2 == ':'
&& ((ch1 >= 'a' && ch1 <= 'z')
|| (ch1 >= 'A' && ch1 <= 'Z'))) {
fileName = fileName.substring(2);
}
}
} else if (osname.indexOf("netware",0) > -1) {
final int colon = fileName.indexOf(':');
if (colon != -1) {
fileName = fileName.substring(colon + 1);
}
}
}
fileName = fileName.replace(File.separatorChar, '/');
// No absolute pathnames
// Windows (and Posix?) paths can start with "\\NetworkDrive\",
// so we loop on starting /'s.
while (fileName.length() > 0 && fileName.charAt(0) == '/') {
fileName = fileName.substring(1);
}
this.linkName = new StringBuilder("");
this.name = new StringBuilder(fileName);
if (file.isDirectory()) {
this.mode = DEFAULT_DIR_MODE;
this.linkFlag = LF_DIR;
if (this.name.charAt(this.name.length() - 1) != '/') {
this.name.append("/");
}
} else {
this.mode = DEFAULT_FILE_MODE;
this.linkFlag = LF_NORMAL;
}
this.size = file.length();
this.modTime = file.lastModified() / MILLIS_PER_SECOND;
this.devMajor = 0;
this.devMinor = 0;
}
/**
* Construct an entry from an archive's header bytes. File is set
* to null.
*
* @param headerBuf The header bytes from a tar archive entry.
*/
public TarEntry(final byte[] headerBuf) {
this();
parseTarHeader(headerBuf);
}
/**
* Determine if the two entries are equal. Equality is determined
* by the header names being equal.
*
* @param it Entry to be checked for equality.
* @return True if the entries are equal.
*/
@Override
public boolean equals(final Object obj) {
if (this == obj) return true;
if (obj == null) return false;
if (!(obj instanceof TarEntry)) return false;
final TarEntry other = (TarEntry) obj;
return getName().equals(other.getName());
}
/**
* Hashcodes are based on entry names.
*
* @return the entry hashcode
*/
@Override
public int hashCode() {
return getName().hashCode();
}
/**
* Determine if the given entry is a descendant of this entry.
* Descendancy is determined by the name of the descendant
* starting with this entry's name.
*
* @param desc Entry to be checked as a descendent of this.
* @return True if entry is a descendant of this.
*/
public boolean isDescendent(final TarEntry desc) {
return desc.getName().startsWith(getName());
}
/**
* Get this entry's name.
*
* @return This entry's name.
*/
public String getName() {
return this.name.toString();
}
/**
* Set this entry's name.
*
* @param name This entry's new name.
*/
public void setName(final String name) {
this.name = new StringBuilder(name);
}
/**
* Set the mode for this entry
*
* @param mode the mode for this entry
*/
public void setMode(final int mode) {
this.mode = mode;
}
/**
* Get this entry's link name.
*
* @return This entry's link name.
*/
public String getLinkName() {
return this.linkName.toString();
}
/**
* Get this entry's user id.
*
* @return This entry's user id.
*/
public int getUserId() {
return this.userId;
}
/**
* Set this entry's user id.
*
* @param userId This entry's new user id.
*/
public void setUserId(final int userId) {
this.userId = userId;
}
/**
* Get this entry's group id.
*
* @return This entry's group id.
*/
public int getGroupId() {
return this.groupId;
}
/**
* Set this entry's group id.
*
* @param groupId This entry's new group id.
*/
public void setGroupId(final int groupId) {
this.groupId = groupId;
}
/**
* Get this entry's user name.
*
* @return This entry's user name.
*/
public String getUserName() {
return this.userName.toString();
}
/**
* Set this entry's user name.
*
* @param userName This entry's new user name.
*/
public void setUserName(final String userName) {
this.userName = new StringBuilder(userName);
}
/**
* Get this entry's group name.
*
* @return This entry's group name.
*/
public String getGroupName() {
return this.groupName.toString();
}
/**
* Set this entry's group name.
*
* @param groupName This entry's new group name.
*/
public void setGroupName(final String groupName) {
this.groupName = new StringBuilder(groupName);
}
/**
* Convenience method to set this entry's group and user ids.
*
* @param userId This entry's new user id.
* @param groupId This entry's new group id.
*/
public void setIds(final int userId, final int groupId) {
setUserId(userId);
setGroupId(groupId);
}
/**
* Convenience method to set this entry's group and user names.
*
* @param userName This entry's new user name.
* @param groupName This entry's new group name.
*/
public void setNames(final String userName, final String groupName) {
setUserName(userName);
setGroupName(groupName);
}
/**
* Set this entry's modification time. The parameter passed
* to this method is in "Java time".
*
* @param time This entry's new modification time.
*/
public void setModTime(final long time) {
this.modTime = time / MILLIS_PER_SECOND;
}
/**
* Set this entry's modification time.
*
* @param time This entry's new modification time.
*/
public void setModTime(final Date time) {
this.modTime = time.getTime() / MILLIS_PER_SECOND;
}
/**
* Set this entry's modification time.
*
* @return time This entry's new modification time.
*/
public Date getModTime() {
return new Date(this.modTime * MILLIS_PER_SECOND);
}
/**
* Get this entry's file.
*
* @return This entry's file.
*/
public File getFile() {
return this.file;
}
/**
* Get this entry's mode.
*
* @return This entry's mode.
*/
public int getMode() {
return this.mode;
}
/**
* Get this entry's file size.
*
* @return This entry's file size.
*/
public long getSize() {
return this.size;
}
/**
* Set this entry's file size.
*
* @param size This entry's new file size.
*/
public void setSize(final long size) {
this.size = size;
}
/**
* Indicate if this entry is a GNU long name block
*
* @return true if this is a long name extension provided by GNU tar
*/
public boolean isGNULongNameEntry() {
return this.linkFlag == LF_GNUTYPE_LONGNAME
&& this.name.toString().equals(GNU_LONGLINK);
}
/**
* Return whether or not this entry represents a directory.
*
* @return True if this entry is a directory.
*/
public boolean isDirectory() {
if (this.file != null) {
return this.file.isDirectory();
}
if (this.linkFlag == LF_DIR) {
return true;
}
if (getName().endsWith("/")) {
return true;
}
return false;
}
/**
* If this entry represents a file, and the file is a directory, return
* an array of TarEntries for this entry's children.
*
* @return An array of TarEntry's for this entry's children.
*/
public TarEntry[] getDirectoryEntries() {
if (this.file == null || !this.file.isDirectory()) {
return new TarEntry[0];
}
final String[] list = this.file.list();
final TarEntry[] result = new TarEntry[list.length];
for (int i = 0; i < list.length; ++i) {
result[i] = new TarEntry(new File(this.file, list[i]));
}
return result;
}
/**
* Write an entry's header information to a header buffer.
*
* @param outbuf The tar entry header buffer to fill in.
*/
public void writeEntryHeader(final byte[] outbuf) {
int offset = 0;
offset = TarUtils.getNameBytes(this.name, outbuf, offset, NAMELEN);
offset = TarUtils.getOctalBytes(this.mode, outbuf, offset, MODELEN);
offset = TarUtils.getOctalBytes(this.userId, outbuf, offset, UIDLEN);
offset = TarUtils.getOctalBytes(this.groupId, outbuf, offset, GIDLEN);
offset = TarUtils.getLongOctalBytes(this.size, outbuf, offset, SIZELEN);
offset = TarUtils.getLongOctalBytes(this.modTime, outbuf, offset, MODTIMELEN);
final int csOffset = offset;
for (int c = 0; c < CHKSUMLEN; ++c) {
outbuf[offset++] = (byte) ' ';
}
outbuf[offset++] = this.linkFlag;
offset = TarUtils.getNameBytes(this.linkName, outbuf, offset, NAMELEN);
offset = TarUtils.getNameBytes(this.magic, outbuf, offset, MAGICLEN);
offset = TarUtils.getNameBytes(this.userName, outbuf, offset, UNAMELEN);
offset = TarUtils.getNameBytes(this.groupName, outbuf, offset, GNAMELEN);
offset = TarUtils.getOctalBytes(this.devMajor, outbuf, offset, DEVLEN);
offset = TarUtils.getOctalBytes(this.devMinor, outbuf, offset, DEVLEN);
while (offset < outbuf.length) {
outbuf[offset++] = 0;
}
final long chk = TarUtils.computeCheckSum(outbuf);
TarUtils.getCheckSumOctalBytes(chk, outbuf, csOffset, CHKSUMLEN);
}
/**
* Parse an entry's header information from a header buffer.
*
* @param header The tar entry header buffer to get information from.
*/
public void parseTarHeader(final byte[] header) {
int offset = 0;
this.name = TarUtils.parseName(header, offset, NAMELEN);
offset += NAMELEN;
this.mode = (int) TarUtils.parseOctal(header, offset, MODELEN);
offset += MODELEN;
this.userId = (int) TarUtils.parseOctal(header, offset, UIDLEN);
offset += UIDLEN;
this.groupId = (int) TarUtils.parseOctal(header, offset, GIDLEN);
offset += GIDLEN;
this.size = TarUtils.parseOctal(header, offset, SIZELEN);
offset += SIZELEN;
this.modTime = TarUtils.parseOctal(header, offset, MODTIMELEN);
offset += MODTIMELEN;
offset += CHKSUMLEN;
this.linkFlag = header[offset++];
this.linkName = TarUtils.parseName(header, offset, NAMELEN);
offset += NAMELEN;
this.magic = TarUtils.parseName(header, offset, MAGICLEN);
offset += MAGICLEN;
this.userName = TarUtils.parseName(header, offset, UNAMELEN);
offset += UNAMELEN;
this.groupName = TarUtils.parseName(header, offset, GNAMELEN);
offset += GNAMELEN;
this.devMajor = (int) TarUtils.parseOctal(header, offset, DEVLEN);
offset += DEVLEN;
this.devMinor = (int) TarUtils.parseOctal(header, offset, DEVLEN);
}
}