/*******************************************************************************
* Copyright (c) 2009 Luaj.org. All rights reserved.
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
******************************************************************************/
package org.luaj.vm2.lib;
import java.io.IOException;
import org.luaj.vm2.LuaTable;
import org.luaj.vm2.LuaValue;
import org.luaj.vm2.Varargs;
/**
* Subclass of {@link LibFunction} which implements the standard lua {@code os} library.
* <p>
* It is a usable base with simplified stub functions
* for library functions that cannot be implemented uniformly
* on Jse and Jme.
* <p>
* This can be installed as-is on either platform, or extended
* and refined to be used in a complete Jse implementation.
* <p>
* Because the nature of the {@code os} library is to encapsulate
* os-specific features, the behavior of these functions varies considerably
* from their counterparts in the C platform.
* <p>
* The following functions have limited implementations of features
* that are not supported well on Jme:
* <ul>
* <li>{@code execute()}</li>
* <li>{@code remove()}</li>
* <li>{@code rename()}</li>
* <li>{@code tmpname()}</li>
* </ul>
* <p>
* Typically, this library is included as part of a call to either
* {@link JmePlatform#standardGlobals()}
* <p>
* To instantiate and use it directly,
* link it into your globals table via {@link LuaValue#load(LuaValue)} using code such as:
* <pre> {@code
* LuaTable _G = new LuaTable();
* LuaThread.setGlobals(_G);
* _G.load(new BaseLib());
* _G.load(new PackageLib());
* _G.load(new OsLib());
* System.out.println( _G.get("os").get("time").call() );
* } </pre>
* Doing so will ensure the library is properly initialized
* and loaded into the globals table.
* <p>
* @see LibFunction
* @see JseOsLib
* @see JsePlatform
* @see JmePlatform
* @see <a href="http://www.lua.org/manual/5.1/manual.html#5.8">http://www.lua.org/manual/5.1/manual.html#5.8</a>
*/
public class OsLib extends VarArgFunction {
public static String TMP_PREFIX = ".luaj";
public static String TMP_SUFFIX = "tmp";
private static final int INIT = 0;
private static final int CLOCK = 1;
private static final int DATE = 2;
private static final int DIFFTIME = 3;
private static final int EXECUTE = 4;
private static final int EXIT = 5;
private static final int GETENV = 6;
private static final int REMOVE = 7;
private static final int RENAME = 8;
private static final int SETLOCALE = 9;
private static final int TIME = 10;
private static final int TMPNAME = 11;
private static final String[] NAMES = {
"clock",
"date",
"difftime",
"execute",
"exit",
"getenv",
"remove",
"rename",
"setlocale",
"time",
"tmpname",
};
private static final long t0 = System.currentTimeMillis();
private static long tmpnames = t0;
/**
* Create and OsLib instance.
*/
public OsLib() {
}
public LuaValue init() {
LuaTable t = new LuaTable();
bind(t, this.getClass(), NAMES, CLOCK);
env.set("os", t);
PackageLib.instance.LOADED.set("os", t);
return t;
}
public Varargs invoke(Varargs args) {
try {
switch ( opcode ) {
case INIT:
return init();
case CLOCK:
return valueOf(clock());
case DATE: {
String s = args.optjstring(1, null);
double t = args.optdouble(2,-1);
return valueOf( date(s, t==-1? System.currentTimeMillis()/1000.: t) );
}
case DIFFTIME:
return valueOf(difftime(args.checkdouble(1),args.checkdouble(2)));
case EXECUTE:
return valueOf(execute(args.optjstring(1, null)));
case EXIT:
exit(args.optint(1, 0));
return NONE;
case GETENV: {
final String val = getenv(args.checkjstring(1));
return val!=null? valueOf(val): NIL;
}
case REMOVE:
remove(args.checkjstring(1));
return LuaValue.TRUE;
case RENAME:
rename(args.checkjstring(1), args.checkjstring(2));
return LuaValue.TRUE;
case SETLOCALE: {
String s = setlocale(args.optjstring(1,null), args.optjstring(2, "all"));
return s!=null? valueOf(s): NIL;
}
case TIME:
return valueOf(time(args.arg1().isnil()? null: args.checktable(1)));
case TMPNAME:
return valueOf(tmpname());
}
return NONE;
} catch ( IOException e ) {
return varargsOf(NIL, valueOf(e.getMessage()));
}
}
/**
* @return an approximation of the amount in seconds of CPU time used by
* the program.
*/
protected double clock() {
return (System.currentTimeMillis()-t0) / 1000.;
}
/**
* Returns the number of seconds from time t1 to time t2.
* In POSIX, Windows, and some other systems, this value is exactly t2-t1.
* @param t2
* @param t1
* @return diffeence in time values, in seconds
*/
protected double difftime(double t2, double t1) {
return t2 - t1;
}
/**
* If the time argument is present, this is the time to be formatted
* (see the os.time function for a description of this value).
* Otherwise, date formats the current time.
*
* If format starts with '!', then the date is formatted in Coordinated
* Universal Time. After this optional character, if format is the string
* "*t", then date returns a table with the following fields: year
* (four digits), month (1--12), day (1--31), hour (0--23), min (0--59),
* sec (0--61), wday (weekday, Sunday is 1), yday (day of the year),
* and isdst (daylight saving flag, a boolean).
*
* If format is not "*t", then date returns the date as a string,
* formatted according to the same rules as the C function strftime.
*
* When called without arguments, date returns a reasonable date and
* time representation that depends on the host system and on the
* current locale (that is, os.date() is equivalent to os.date("%c")).
*
* @param format
* @param time time since epoch, or -1 if not supplied
* @return a LString or a LTable containing date and time,
* formatted according to the given string format.
*/
protected String date(String format, double time) {
return new java.util.Date((long)(time*1000)).toString();
}
/**
* This function is equivalent to the C function system.
* It passes command to be executed by an operating system shell.
* It returns a status code, which is system-dependent.
* If command is absent, then it returns nonzero if a shell
* is available and zero otherwise.
* @param command command to pass to the system
*/
protected int execute(String command) {
return 0;
}
/**
* Calls the C function exit, with an optional code, to terminate the host program.
* @param code
*/
protected void exit(int code) {
System.exit(code);
}
/**
* Returns the value of the process environment variable varname,
* or null if the variable is not defined.
* @param varname
* @return String value, or null if not defined
*/
protected String getenv(String varname) {
return System.getProperty(varname);
}
/**
* Deletes the file or directory with the given name.
* Directories must be empty to be removed.
* If this function fails, it throws and IOException
*
* @param filename
* @throws IOException if it fails
*/
protected void remove(String filename) throws IOException {
throw new IOException( "not implemented" );
}
/**
* Renames file or directory named oldname to newname.
* If this function fails,it throws and IOException
*
* @param oldname old file name
* @param newname new file name
* @throws IOException if it fails
*/
protected void rename(String oldname, String newname) throws IOException {
throw new IOException( "not implemented" );
}
/**
* Sets the current locale of the program. locale is a string specifying
* a locale; category is an optional string describing which category to change:
* "all", "collate", "ctype", "monetary", "numeric", or "time"; the default category
* is "all".
*
* If locale is the empty string, the current locale is set to an implementation-
* defined native locale. If locale is the string "C", the current locale is set
* to the standard C locale.
*
* When called with null as the first argument, this function only returns the
* name of the current locale for the given category.
*
* @param locale
* @param category
* @return the name of the new locale, or null if the request
* cannot be honored.
*/
protected String setlocale(String locale, String category) {
return "C";
}
/**
* Returns the current time when called without arguments,
* or a time representing the date and time specified by the given table.
* This table must have fields year, month, and day,
* and may have fields hour, min, sec, and isdst
* (for a description of these fields, see the os.date function).
* @param table
* @return long value for the time
*/
protected long time(LuaTable table) {
return System.currentTimeMillis();
}
/**
* Returns a string with a file name that can be used for a temporary file.
* The file must be explicitly opened before its use and explicitly removed
* when no longer needed.
*
* On some systems (POSIX), this function also creates a file with that name,
* to avoid security risks. (Someone else might create the file with wrong
* permissions in the time between getting the name and creating the file.)
* You still have to open the file to use it and to remove it (even if you
* do not use it).
*
* @return String filename to use
*/
protected String tmpname() {
synchronized ( OsLib.class ) {
return TMP_PREFIX+(tmpnames++)+TMP_SUFFIX;
}
}
}