BEGIN LICENSE BLOCK *****
Version: EPL 2.0/GPL 2.0/LGPL 2.1
The contents of this file are subject to the Eclipse Public
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.eclipse.org/legal/epl-v20.html
Software distributed under the License is distributed on an "AS
IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or
implied. See the License for the specific language governing
rights and limitations under the License.
Copyright (C) 2007 Ola Bini 
Alternatively, the contents of this file may be used under the terms of
either of the GNU General Public License Version 2 or later (the "GPL"),
or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
in which case the provisions of the GPL or the LGPL are applicable instead
of those above. If you wish to allow use of your version of this file only
under the terms of either the GPL or the LGPL, and not to allow others to
use your version of this file under the terms of the EPL, indicate your
decision by deleting the provisions above and replace them with the notice
and other provisions required by the GPL or the LGPL. If you do not delete
the provisions above, a recipient may use your version of this file under
the terms of any one of the EPL, the GPL or the LGPL.
END LICENSE BLOCK /***** BEGIN LICENSE BLOCK *****
 * Version: EPL 2.0/GPL 2.0/LGPL 2.1
 *
 * The contents of this file are subject to the Eclipse Public
 * 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.eclipse.org/legal/epl-v20.html
 *
 * Software distributed under the License is distributed on an "AS
 * IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or
 * implied. See the License for the specific language governing
 * rights and limitations under the License.
 *
 * Copyright (C) 2007 Ola Bini <ola@ologix.com>
 * 
 * Alternatively, the contents of this file may be used under the terms of
 * either of the GNU General Public License Version 2 or later (the "GPL"),
 * or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
 * in which case the provisions of the GPL or the LGPL are applicable instead
 * of those above. If you wish to allow use of your version of this file only
 * under the terms of either the GPL or the LGPL, and not to allow others to
 * use your version of this file under the terms of the EPL, indicate your
 * decision by deleting the provisions above and replace them with the notice
 * and other provisions required by the GPL or the LGPL. If you do not delete
 * the provisions above, a recipient may use your version of this file under
 * the terms of any one of the EPL, the GPL or the LGPL.
 ***** END LICENSE BLOCK *****/

package org.jruby;

import jnr.constants.platform.Signal;

import org.jruby.anno.JRubyMethod;
import org.jruby.anno.JRubyModule;
import org.jruby.platform.Platform;
import org.jruby.runtime.ThreadContext;
import org.jruby.runtime.builtin.IRubyObject;
import org.jruby.util.SignalFacade;
import org.jruby.util.NoFunctionalitySignalFacade;

import java.util.*;

@JRubyModule(name="Signal")
public class RubySignal {

    private final static SignalFacade SIGNAL_FACADE = initSignalFacade();

    private final static SignalFacade initSignalFacade() {
        try {
            return org.jruby.util.SunSignalFacade.class.newInstance();
        } catch (Throwable e) {
            return new NoFunctionalitySignalFacade();
        }
    }
    
    public static void createSignal(Ruby runtime) {
        // We force java.lang.Process et al to load so that JVM's CHLD handler can be
        // overwritten by users (jruby/jruby#3283)
        if (!Platform.IS_WINDOWS) {
            try {
                Class.forName("java.lang.Process");
                Class.forName("java.lang.UNIXProcess");
            } catch (Throwable t) {
                // if we can't access Process, other things will fail anyway; ignore for now
            }
        }

        RubyModule mSignal = runtime.defineModule("Signal");
        
        mSignal.defineAnnotatedMethods(RubySignal.class);
        //registerThreadDumpSignalHandler(runtime);
    }

    private static final String SIGNAME_PREFIX = "SIG";
    private static final Map<String, Integer> SIGNAME_MAP;
    private static final Map<Integer, String> SIGNUM_MAP;

    static {
        HashMap<String, Integer> signals = new HashMap<>();
        HashMap<Integer, String> signums = new HashMap<>();

        for (Signal s : Signal.values()) {
            // Skip signals not defined on this platform
            if (!s.defined()) continue;

            String desc = s.description();
            if (!desc.startsWith(SIGNAME_PREFIX)) continue;

            desc = signmWithoutPrefix(desc);
            if (!SIGNAME(desc)) continue;

            // replace CLD with CHLD value
            int signo = s.intValue();
            if (s == Signal.SIGCLD)
                signo = Signal.SIGCHLD.intValue();

            // omit unsupported signals
            if (signo >= 20000) continue;

            signals.put(desc, signo);
            signums.put(signo, desc);
        }

        // We always define KILL as 9 on Windows
        if (Platform.IS_WINDOWS) {
            signals.put("KILL", 9);
        }

        SIGNAME_MAP = Collections.unmodifiableMap(signals);
        SIGNUM_MAP = Collections.unmodifiableMap(signums);
    }
    
    public static Map<String, Integer> list() {
        return SIGNAME_MAP;
    }

    @JRubyMethod(meta = true)
    public static IRubyObject list(ThreadContext context, IRubyObject recv) {
        Ruby runtime = recv.getRuntime();
        RubyHash names;

        synchronized (recv) {
            names = (RubyHash) recv.getInternalVariables().getInternalVariable("signal_list");
            if (names == null) {
                names = RubyHash.newHash(runtime);
                for (Map.Entry<String, Integer> sig : RubySignal.list().entrySet()) {
                    names.op_aset(context, runtime.freezeAndDedupString(runtime.newString(sig.getKey())), runtime.newFixnum(sig.getValue()));
                }
                names.op_aset(context, runtime.freezeAndDedupString(runtime.newString("EXIT")), runtime.newFixnum(0));
                recv.getInternalVariables().setInternalVariable("signal_list", names);
            } else {
                names.dup(context);
            }
        }
        
        return names;
    }

    @JRubyMethod(required = 2, meta = true)
    public static IRubyObject __jtrap_kernel(final IRubyObject recv, IRubyObject block, IRubyObject sig) {
        return SIGNAL_FACADE.trap(recv, block, sig);
    }

    @JRubyMethod(required = 1, meta = true)
    public static IRubyObject __jtrap_platform_kernel(final IRubyObject recv, IRubyObject sig) {
        return SIGNAL_FACADE.restorePlatformDefault(recv, sig);
    }

    @JRubyMethod(required = 1, meta = true)
    public static IRubyObject __jtrap_osdefault_kernel(final IRubyObject recv, IRubyObject sig) {
        return SIGNAL_FACADE.restoreOSDefault(recv, sig);
    }

    @JRubyMethod(required = 1, meta = true)
    public static IRubyObject __jtrap_restore_kernel(final IRubyObject recv, IRubyObject sig) {
        return SIGNAL_FACADE.ignore(recv, sig);
    }

    @JRubyMethod(required = 1, meta = true)
    public static IRubyObject signame(ThreadContext context, final IRubyObject recv, IRubyObject rubySig) {
        long sig = rubySig.convertToInteger().getLongValue();
        String signame = signo2signm(sig);
        if (signame == null) {
            if(sig == 0) {
                return RubyString.newString(context.runtime, "EXIT");
            } else {
                throw context.runtime.newArgumentError("invalid signal number: " + rubySig);
            }
        }
        return context.runtime.newString(signame);
    }

    // MRI: signo2signm
    public static String signo2signm(long no) {
        return SIGNUM_MAP.get((int) no);
    }

    // MRI: signm2signo
    public static long signm2signo(String nm) {
        Integer signo = SIGNAME_MAP.get(nm);

        if (signo == null) return 0;

        return signo;
    }

    public static String signmWithPrefix(String nm) {
        return (nm.startsWith(SIGNAME_PREFIX)) ? nm : SIGNAME_PREFIX + nm;
    }

    public static String signmWithoutPrefix(String nm) {
        return (nm.startsWith(SIGNAME_PREFIX)) ? nm.substring(SIGNAME_PREFIX.length()) : nm;
    }

    private static boolean SIGNAME(final String name) {
        switch (name) {
            case "EXIT":
            case "HUP" :
            case "INT" :
            case "QUIT":
            case "ILL" :
            case "TRAP":
            case "IOT" :
            case "ABRT":
            case "EMT" :
            case "FPE" :
            case "KILL":
            case "BUS" :
            case "SEGV":
            case "SYS" :
            case "PIPE":
            case "ALRM":
            case "TERM":
            case "URG" :
            case "STOP":
            case "TSTP":
            case "CONT":
            case "CHLD":
            case "CLD" :
            case "TTIN":
            case "TTOU":
            case "IO"  :
            case "XCPU":
            case "XFSZ":
            case "PROF":
            case "VTALRM":
            case "WINCH":
            case "USR1":
            case "USR2":
            case "LOST":
            case "MSG" :
            case "PWR" :
            case "POLL":
            case "DANGER":
            case "MIGRATE":
            case "PRE" :
            case "GRANT":
            case "RETRACT":
            case "SOUND":
            case "INFO":
                return true;
            default:
                return false;
        }
    }

}