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) 2006 Nick Sieger 
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) 2006 Nick Sieger <nicksieger@gmail.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.ext.io.wait;

import org.jruby.Ruby;
import org.jruby.RubyClass;
import org.jruby.RubyIO;
import org.jruby.RubyNumeric;
import org.jruby.RubySymbol;
import org.jruby.RubyTime;
import org.jruby.anno.JRubyMethod;
import org.jruby.runtime.Helpers;
import org.jruby.runtime.ThreadContext;
import org.jruby.runtime.builtin.IRubyObject;
import org.jruby.runtime.load.Library;
import org.jruby.util.io.OpenFile;

import java.nio.channels.SelectionKey;

Author:
Nick Sieger/**
 * @author Nick Sieger
 */
public class IOWaitLibrary implements Library {

    public void load(Ruby runtime, boolean wrap) {
        RubyClass ioClass = runtime.getIO();
        ioClass.defineAnnotatedMethods(IOWaitLibrary.class);
    }

    @JRubyMethod
    public static IRubyObject nread(ThreadContext context, IRubyObject _io) {
        Ruby runtime = context.runtime;
        OpenFile fptr;
        int len;
//        ioctl_arg n;
        RubyIO io = (RubyIO)_io;

        fptr = io.getOpenFileChecked();
        fptr.checkReadable(context);
        len = fptr.readPending();
        if (len > 0) return runtime.newFixnum(len);
        // TODO: better effort to get available bytes from our channel
//        if (!FIONREAD_POSSIBLE_P(fptr->fd)) return INT2FIX(0);
//        if (ioctl(fptr->fd, FIONREAD, &n)) return INT2FIX(0);
//        if (n > 0) return ioctl_arg2num(n);
        // Because we can't get an actual system-level buffer available count, we fake it by returning 1 if ready
        return RubyNumeric.int2fix(runtime, fptr.readyNow(context) ? 1 : 0);
    }

    
returns non-nil if input available without blocking, false if EOF or not open/readable, otherwise nil.
/**
     * returns non-nil if input available without blocking, false if EOF or not open/readable, otherwise nil.
     */
    @JRubyMethod(name = "ready?")
    public static IRubyObject ready(ThreadContext context, IRubyObject _io) {
        RubyIO io = (RubyIO)_io;
        Ruby runtime = context.runtime;
        OpenFile fptr;
//        ioctl_arg n;

        fptr = io.getOpenFileChecked();
        fptr.checkReadable(context);
        if (fptr.readPending() != 0) return runtime.getTrue();
        // TODO: better effort to get available bytes from our channel
//        if (!FIONREAD_POSSIBLE_P(fptr->fd)) return Qnil;
//        if (ioctl(fptr->fd, FIONREAD, &n)) return Qnil;
//        if (n > 0) return Qtrue;
        return runtime.newBoolean(fptr.readyNow(context));
    }

    @JRubyMethod(optional = 1)
    public static IRubyObject wait_readable(ThreadContext context, IRubyObject _io, IRubyObject[] argv) {
        RubyIO io = (RubyIO)_io;
        OpenFile fptr = io.getOpenFileChecked();

        fptr.checkReadable(context);

        long tv = prepareTimeout(context, argv);

        if (fptr.readPending() != 0) return context.tru;

        return doWait(context, io, fptr, tv, SelectionKey.OP_READ | SelectionKey.OP_ACCEPT);
    }

    
waits until input available or timed out and returns self, or nil when EOF reached.
/**
     * waits until input available or timed out and returns self, or nil when EOF reached.
     */
    @JRubyMethod(optional = 1)
    public static IRubyObject wait_writable(ThreadContext context, IRubyObject _io, IRubyObject[] argv) {
        RubyIO io = (RubyIO)_io;

        OpenFile fptr = io.getOpenFileChecked();

        fptr.checkWritable(context);

        long tv = prepareTimeout(context, argv);

        return doWait(context, io, fptr, tv, SelectionKey.OP_CONNECT | SelectionKey.OP_WRITE);
    }

    @JRubyMethod(optional = 2)
    public static IRubyObject wait(ThreadContext context, IRubyObject _io, IRubyObject[] argv) {
        RubyIO io = (RubyIO)_io;

        OpenFile fptr = io.getOpenFileChecked();

        int ops = 0;

        if (argv.length == 2) {
            if (argv[1] instanceof RubySymbol) {
                RubySymbol sym = (RubySymbol) argv[1];
                switch (sym.asJavaString()) { // 7 bit comparison
                    case "r":
                    case "read":
                    case "readable":
                        ops |= SelectionKey.OP_ACCEPT | SelectionKey.OP_READ;
                        break;
                    case "w":
                    case "write":
                    case "writable":
                        ops |= SelectionKey.OP_CONNECT | SelectionKey.OP_WRITE;
                        break;
                    case "rw":
                    case "read_write":
                    case "readable_writable":
                        ops |= SelectionKey.OP_ACCEPT | SelectionKey.OP_READ | SelectionKey.OP_CONNECT | SelectionKey.OP_WRITE;
                        break;
                    default:
                        throw context.runtime.newArgumentError("unsupported mode: " + sym);
                }
            } else {
                throw context.runtime.newArgumentError("unsupported mode: " + argv[1].getType());
            }
        } else {
            ops |= SelectionKey.OP_ACCEPT | SelectionKey.OP_READ;
        }

        if ((ops & SelectionKey.OP_READ) == SelectionKey.OP_READ && fptr.readPending() != 0) return context.tru;

        long tv = prepareTimeout(context, argv);

        return doWait(context, io, fptr, tv, ops);
    }

    private static IRubyObject doWait(ThreadContext context, RubyIO io, OpenFile fptr, long tv, int ops) {
        boolean ready = fptr.ready(context.runtime, context.getThread(), ops, tv);
        fptr.checkClosed();
        if (ready) return io;
        return context.nil;
    }

    private static long prepareTimeout(ThreadContext context, IRubyObject[] argv) {
        IRubyObject timeout;
        long tv;
        switch (argv.length) {
            case 2:
            case 1:
                timeout = argv[0];
                break;
            default:
                timeout = context.nil;
        }

        if (timeout.isNil()) {
            tv = -1;
        }
        else {
            tv = (long)(RubyTime.convertTimeInterval(context, timeout) * 1000);
            if (tv < 0) throw context.runtime.newArgumentError("time interval must be positive");
        }
        return tv;
    }
}