package java.nio.file;

import java.util.Set;

import java.util.EnumSet;

import java.security.SecureRandom;

import static java.security.AccessController.*;

import java.io.IOException;

import java.nio.file.attribute.FileAttribute;

import java.nio.file.attribute.PosixFilePermission;

import java.nio.file.attribute.PosixFilePermissions;

import static java.nio.file.attribute.PosixFilePermission.*;

import sun.security.action.GetPropertyAction;

class TempFileHelper {

private TempFileHelper() { }

// temporary directory location

private static final Path tmpdir =

Paths.get(doPrivileged(new GetPropertyAction("java.io.tmpdir")));

private static final boolean isPosix =

FileSystems.getDefault().supportedFileAttributeViews().contains("posix");

// file name generation, same as java.io.File for now

private static final SecureRandom random = new SecureRandom();

private static Path generatePath(String prefix, String suffix, Path dir) {

long n = random.nextLong();

n = (n == Long.MIN_VALUE) ? 0 : Math.abs(n);

Path name = dir.getFileSystem().getPath(prefix + Long.toString(n) + suffix);

// the generated name should be a simple file name

if (name.getParent() != null)

throw new IllegalArgumentException("Invalid prefix or suffix");

return dir.resolve(name);

}

// default file and directory permissions (lazily initialized)

private static class PosixPermissions {

static final FileAttribute<Set<PosixFilePermission>> filePermissions =

PosixFilePermissions.asFileAttribute(EnumSet.of(OWNER_READ, OWNER_WRITE));

static final FileAttribute<Set<PosixFilePermission>> dirPermissions =

PosixFilePermissions.asFileAttribute(EnumSet

.of(OWNER_READ, OWNER_WRITE, OWNER_EXECUTE));

}

/**

private static Path create(Path dir,

String prefix,

String suffix,

boolean createDirectory,

FileAttribute[] attrs)

throws IOException

{

if (prefix == null)

prefix = "";

if (suffix == null)

suffix = (createDirectory) ? "" : ".tmp";

if (dir == null)

dir = tmpdir;

// in POSIX environments use default file and directory permissions

// if initial permissions not given by caller.

if (isPosix && (dir.getFileSystem() == FileSystems.getDefault())) {

if (attrs.length == 0) {

// no attributes so use default permissions

attrs = new FileAttribute<?>[1];

attrs[0] = (createDirectory) ? PosixPermissions.dirPermissions :

PosixPermissions.filePermissions;

} else {

// check if posix permissions given; if not use default

boolean hasPermissions = false;

for (int i=0; i<attrs.length; i++) {

if (attrs[i].name().equals("posix:permissions")) {

hasPermissions = true;

break;

}

}

if (!hasPermissions) {

FileAttribute<?>[] copy = new FileAttribute<?>[attrs.length+1];

System.arraycopy(attrs, 0, copy, 0, attrs.length);

attrs = copy;

attrs[attrs.length-1] = (createDirectory) ?

PosixPermissions.dirPermissions :

PosixPermissions.filePermissions;

}

}

}

// loop generating random names until file or directory can be created

SecurityManager sm = System.getSecurityManager();

for (;;) {

Path f;

try {

f = generatePath(prefix, suffix, dir);

} catch (InvalidPathException e) {

// don't reveal temporary directory location

if (sm != null)

throw new IllegalArgumentException("Invalid prefix or suffix");

throw e;

}

try {

if (createDirectory) {

return Files.createDirectory(f, attrs);

} else {

return Files.createFile(f, attrs);

}

} catch (SecurityException e) {

// don't reveal temporary directory location

if (dir == tmpdir && sm != null)

throw new SecurityException("Unable to create temporary file or directory");

throw e;

} catch (FileAlreadyExistsException e) {

// ignore

}

}

}

/**

static Path createTempFile(Path dir,

String prefix,

String suffix,

FileAttribute[] attrs)

throws IOException

{

return create(dir, prefix, suffix, false, attrs);

}

/**

static Path createTempDirectory(Path dir,

String prefix,

FileAttribute[] attrs)

throws IOException

{

return create(dir, prefix, null, true, attrs);

}

}