Native.java

/**
 * This file is part of Erjang - A JVM-based Erlang VM
 *
 * Copyright (c) 2009 by Trifork
 *
 * 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 erjang.m.os;

import java.lang.management.ManagementFactory;
import java.lang.management.RuntimeMXBean;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
import java.util.Map;

import erjang.BIF;
import erjang.EAtom;
import erjang.ENative;
import erjang.EObject;
import erjang.ERT;
import erjang.EString;
import erjang.ETuple2;
import erjang.ETuple3;
import erjang.ECons;
import erjang.ErjangConfig;
import erjang.NotImplemented;

/**
 * Native methods (BIFs) for the Erlang module 'os'.
 * 
 * The fact that this class represents the module os is deduced from the package
 * name,
 */
public class Native extends ENative {

	/**
	 * 
	 */
	private static final EAtom am_unix = EAtom.intern("unix");
	private static final EAtom am_win32 = EAtom.intern("win32");

	private static final EAtom am_darwin = EAtom.intern("darwin");
	private static final EAtom am_linux = EAtom.intern("linux");
	private static final EAtom am_sunos = EAtom.intern("sunos");
	private static final EAtom am_windows = EAtom.intern("windows");
	private static final EAtom am_nt = EAtom.intern("nt");

	private static final ETuple2 OS_TYPE_MACOS = new ETuple2(am_unix, am_darwin);
	private static final ETuple2 OS_TYPE_LINUX = new ETuple2(am_unix, am_linux);
	private static final ETuple2 OS_TYPE_SUNOS = new ETuple2(am_unix, am_sunos);
	private static final ETuple2 OS_TYPE_WINDOWS = new ETuple2(am_win32,
			am_windows);
	private static final ETuple2 OS_TYPE_WINNT = new ETuple2(am_win32, am_nt);

	
	/** os:putenv(string(), string()) -> true */
	@BIF
	public static EObject putenv(EObject o1, EObject o2) {
		EString str1 = o1.testString();
		EString str2 = o2.testString();
		if (str1 == null || str2 == null)
			throw ERT.badarg(o1, o2);
		
		ErjangConfig.setenv(str1.stringValue(), str2.stringValue());
		
		return ERT.TRUE;
	}
	
	/** os:getenv(string()) -> string() | false */
	@BIF
	public static EObject getenv(EObject o) {
		EString str = o.testString();
		if (str == null)
			throw ERT.badarg(o);

		String value;
		
		value = ErjangConfig.getenv(str.stringValue());
		if (value != null) {
			return EString.fromString(value);
		}
		
		value = System.getenv(str.stringValue());

		if (value == null) {
			return ERT.FALSE;
		} else {
			return EString.fromString(value);
		}
	}

	/** os:getenv() -> [string()] */
	@BIF
	public static EObject getenv() {
		Map<String,String> env = System.getenv();

		ECons res = ERT.NIL;
		for (Map.Entry<String,String> entry : env.entrySet()) {
			String s = entry.getKey() + "=" + entry.getValue();
			res = res.cons(EString.fromString(s));
		}
		return res;
	}

	@BIF
	public static ETuple2 type() {
		String osname = System.getProperty("os.name");
		/*
		 * TODO: On unices, the second element should always be lowercase of
		 * `uname -s`. For now, we recognize a fixed set.
		 */
		if ("Mac OS".equals(osname) || "Mac OS X".equals(osname))
			return OS_TYPE_MACOS;
		if ("Linux".equals(osname))
			return OS_TYPE_LINUX;
		if ("Solaris".equals(osname) || "SunOS".equals(osname))
			return OS_TYPE_SUNOS;
		if ("Windows 95".equals(osname) || "Windows 98".equals(osname)
				|| "Windows Me".equals(osname))
			return OS_TYPE_WINDOWS;
		if ("Windows NT".equals(osname) || "Windows 2000".equals(osname)
				|| "Windows XP".equals(osname))
			return OS_TYPE_WINNT;
		// Fallback:
		return OS_TYPE_MACOS;
	}

	@BIF
	public static EObject getpid() {

		RuntimeMXBean rtb = ManagementFactory.getRuntimeMXBean();
		String processName = rtb.getName();
		Integer pid = tryPattern1(processName);

		if (pid == null) {
			throw new NotImplemented();
		}
		
		return EString.fromString(String.valueOf(pid));
	}

	/** from http://golesny.de/wiki/code:javahowtogetpid; that site has more suggestions if this fails...*/
	private static Integer tryPattern1(String processName) {
		Integer result = null;

		/* tested on: */
		/* - windows xp sp 2, java 1.5.0_13 */
		/* - mac os x 10.4.10, java 1.5.0 */
		/* - debian linux, java 1.5.0_13 */
		/* all return pid@host, e.g 2204@antonius */

		Pattern pattern = Pattern.compile("^([0-9]+)@.+$",
				Pattern.CASE_INSENSITIVE);
		Matcher matcher = pattern.matcher(processName);
		if (matcher.matches()) {
			result = new Integer(Integer.parseInt(matcher.group(1)));
		}
		return result;
		
		
	}

	@BIF
	static public ETuple3 timestamp() {
		long now = erjang.m.erlang.ErlTime.now_raw_micros();
		int micros = (int)(now % 1000000); now /= 1000000;
		int secs   = (int)(now % 1000000); now /= 1000000;
		int megas  = (int)now;

		ETuple3 res = new ETuple3();

		res.elem1 = ERT.box(megas);
		res.elem2 = ERT.box(secs);
		res.elem3 = ERT.box(micros);

		return res;
	}

}