// Copyright 2014 The Bazel Authors. All rights reserved.
//
// 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.google.devtools.build.lib.unix;
/**
* <p>Equivalent to UNIX's "struct stat", a FileStatus instance contains
* various bits of metadata about a directory entry.
*
* <p>The Java SDK provides access to some but not all of the information
* available via the stat(2) and lstat(2) syscalls, but often requires that
* multiple calls be made to obtain it. By reifying stat buffers as Java
* objects and providing a wrapper around the stat/lstat calls, we give client
* applications access to the richer file metadata and enable a reduction in
* the number of system calls, which is critical for high-performance tools.
*
* <p>This class is optimized for memory usage. Operations that are not yet
* required for any client are intentionally unimplemented to save space.
* Currently, we only support these fields: st_mode, st_size, st_atime,
* st_atimensec, st_mtime, st_mtimensec, st_ctime, st_ctimensec, st_dev, st_ino.
* Methods that require other fields throw UnsupportedOperationException.
*/
public class FileStatus {
private final int st_mode;
private final int st_atime; // (unsigned)
private final int st_atimensec; // (unsigned)
private final int st_mtime; // (unsigned)
private final int st_mtimensec; // (unsigned)
private final int st_ctime; // (unsigned)
private final int st_ctimensec; // (unsigned)
private final long st_size;
private final int st_dev;
private final long st_ino;
/**
* Constructs a FileStatus instance. (Called only from JNI code.)
*/
protected FileStatus(int st_mode, int st_atime, int st_atimensec, int st_mtime, int st_mtimensec,
int st_ctime, int st_ctimensec, long st_size, int st_dev, long st_ino) {
this.st_mode = st_mode;
this.st_atime = st_atime;
this.st_atimensec = st_atimensec;
this.st_mtime = st_mtime;
this.st_mtimensec = st_mtimensec;
this.st_ctime = st_ctime;
this.st_ctimensec = st_ctimensec;
this.st_size = st_size;
this.st_dev = st_dev;
this.st_ino = st_ino;
}
/**
* Returns the device number of this inode.
*/
public int getDeviceNumber() {
return st_dev;
}
/**
* Returns the number of this inode. Inode numbers are (usually) unique for
* a given device.
*/
public long getInodeNumber() {
return st_ino;
}
/**
* Returns true iff this file is a regular file.
*/
public boolean isRegularFile() {
return (st_mode & S_IFMT) == S_IFREG;
}
/**
* Returns true iff this file is a directory.
*/
public boolean isDirectory() {
return (st_mode & S_IFMT) == S_IFDIR;
}
/**
* Returns true iff this file is a symbolic link.
*/
public boolean isSymbolicLink() {
return (st_mode & S_IFMT) == S_IFLNK;
}
/**
* Returns true iff this file is a character device.
*/
public boolean isCharacterDevice() {
return (st_mode & S_IFMT) == S_IFCHR;
}
/**
* Returns true iff this file is a block device.
*/
public boolean isBlockDevice() {
return (st_mode & S_IFMT) == S_IFBLK;
}
/**
* Returns true iff this file is a FIFO.
*/
public boolean isFIFO() {
return (st_mode & S_IFMT) == S_IFIFO;
}
/**
* Returns true iff this file is a UNIX-domain socket.
*/
public boolean isSocket() {
return (st_mode & S_IFMT) == S_IFSOCK;
}
/**
* Returns true iff this file has its "set UID" bit set.
*/
public boolean isSetUserId() {
return (st_mode & S_ISUID) != 0;
}
/**
* Returns true iff this file has its "set GID" bit set.
*/
public boolean isSetGroupId() {
return (st_mode & S_ISGID) != 0;
}
/**
* Returns true iff this file has its "sticky" bit set. See UNIX manuals for
* explanation.
*/
public boolean isSticky() {
return (st_mode & S_ISVTX) != 0;
}
/**
* Returns the user/group/other permissions part of the mode bits (i.e.
* st_mode masked with 0777), interpreted according to longstanding UNIX
* tradition.
*/
public int getPermissions() {
return st_mode & S_IRWXA;
}
/**
* Returns the total size, in bytes, of this file.
*/
public long getSize() {
return st_size;
}
/**
* Returns the last access time of this file (seconds since UNIX epoch).
*/
public long getLastAccessTime() {
return unsignedIntToLong(st_atime);
}
/**
* Returns the fractional part of the last access time of this file (nanoseconds).
*/
public long getFractionalLastAccessTime() {
return unsignedIntToLong(st_atimensec);
}
/**
* Returns the last modified time of this file (seconds since UNIX epoch).
*/
public long getLastModifiedTime() {
return unsignedIntToLong(st_mtime);
}
/**
* Returns the fractional part of the last modified time of this file (nanoseconds).
*/
public long getFractionalLastModifiedTime() {
return unsignedIntToLong(st_mtimensec);
}
/**
* Returns the last change time of this file (seconds since UNIX epoch).
*/
public long getLastChangeTime() {
return unsignedIntToLong(st_ctime);
}
/**
* Returns the fractional part of the last change time of this file (nanoseconds).
*/
public long getFractionalLastChangeTime() {
return unsignedIntToLong(st_ctimensec);
}
////////////////////////////////////////////////////////////////////////
@Override
public String toString() {
return String.format("FileStatus(mode=0%06o,size=%d,mtime=%d)",
st_mode, st_size, st_mtime);
}
@Override
public int hashCode() {
return st_mode;
}
////////////////////////////////////////////////////////////////////////
// Platform-specific details. These fields are public so that they can
// be used from other packages. See POSIX and/or Linux manuals for details.
//
// These need to be kept in sync with the native code and system call
// interface. (The unit tests ensure that.) Of course, this decoding could
// be done in the JNI code to ensure maximum portability, but (a) we don't
// expect we'll need that any time soon, and (b) that would require eager
// rather than on-demand bitmunging of all attributes. In any case, it's not
// part of the interface so it can be easily changed later if necessary.
public static final int S_IFMT = 0170000; // mask: filetype bitfields
public static final int S_IFSOCK = 0140000; // socket
public static final int S_IFLNK = 0120000; // symbolic link
public static final int S_IFREG = 0100000; // regular file
public static final int S_IFBLK = 0060000; // block device
public static final int S_IFDIR = 0040000; // directory
public static final int S_IFCHR = 0020000; // character device
public static final int S_IFIFO = 0010000; // fifo
public static final int S_ISUID = 0004000; // set UID bit
public static final int S_ISGID = 0002000; // set GID bit (see below)
public static final int S_ISVTX = 0001000; // sticky bit (see below)
public static final int S_IRWXA = 00777; // mask: all permissions
public static final int S_IRWXU = 00700; // mask: file owner permissions
public static final int S_IRUSR = 00400; // owner has read permission
public static final int S_IWUSR = 00200; // owner has write permission
public static final int S_IXUSR = 00100; // owner has execute permission
public static final int S_IRWXG = 00070; // mask: group permissions
public static final int S_IRGRP = 00040; // group has read permission
public static final int S_IWGRP = 00020; // group has write permission
public static final int S_IXGRP = 00010; // group has execute permission
public static final int S_IRWXO = 00007; // mask: other permissions
public static final int S_IROTH = 00004; // others have read permission
public static final int S_IWOTH = 00002; // others have write permisson
public static final int S_IXOTH = 00001; // others have execute permission
public static final int S_IEXEC = 00111; // owner, group, world execute
static long unsignedIntToLong(int i) {
return (i & 0x7FFFFFFF) - (long) (i & 0x80000000);
}
public static boolean isFile(int rawType) {
int type = rawType & S_IFMT;
return type == S_IFREG || isSpecialFile(rawType);
}
public static boolean isSpecialFile(int rawType) {
int type = rawType & S_IFMT;
return type == S_IFSOCK || type == S_IFBLK || type == S_IFCHR || type == S_IFIFO;
}
public static boolean isDirectory(int rawType) {
int type = rawType & S_IFMT;
return type == S_IFDIR;
}
public static boolean isSymbolicLink(int rawType) {
int type = rawType & S_IFMT;
return type == S_IFLNK;
}
}