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Annotation of driverkit/libDriver/Kernel/IOEventSource.m, revision 1.1

1.1     ! root        1: /*
        !             2:  * Copyright (c) 1999 Apple Computer, Inc. All rights reserved.
        !             3:  *
        !             4:  * @APPLE_LICENSE_HEADER_START@
        !             5:  * 
        !             6:  * Portions Copyright (c) 1999 Apple Computer, Inc.  All Rights
        !             7:  * Reserved.  This file contains Original Code and/or Modifications of
        !             8:  * Original Code as defined in and that are subject to the Apple Public
        !             9:  * Source License Version 1.1 (the "License").  You may not use this file
        !            10:  * except in compliance with the License.  Please obtain a copy of the
        !            11:  * License at http://www.apple.com/publicsource and read it before using
        !            12:  * this file.
        !            13:  * 
        !            14:  * The Original Code and all software distributed under the License are
        !            15:  * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
        !            16:  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
        !            17:  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
        !            18:  * FITNESS FOR A PARTICULAR PURPOSE OR NON- INFRINGEMENT.  Please see the
        !            19:  * License for the specific language governing rights and limitations
        !            20:  * under the License.
        !            21:  * 
        !            22:  * @APPLE_LICENSE_HEADER_END@
        !            23:  */
        !            24: /*     Copyright (c) 1992 NeXT Computer, Inc.  All rights reserved. 
        !            25:  *
        !            26:  * IOEventSource.m - Common Event Source object class.  This is an abstract
        !            27:  *             class which implements a device ownership protocol, and 
        !            28:  *             provides a core of common services for working Event Source 
        !            29:  *             objects to take advantage of.
        !            30:  *
        !            31:  * HISTORY
        !            32:  * 22 May 1992    Mike Paquette at NeXT
        !            33:  *      Created. 
        !            34:  * 4  Aug 1993   Erik Kay at NeXT
        !            35:  *     API cleanup
        !            36:  */
        !            37: 
        !            38: #define KERNEL_PRIVATE 1
        !            39: 
        !            40: #import <driverkit/IOEventSource.h> 
        !            41: #import <driverkit/EventInput.h>
        !            42: #import <driverkit/eventProtocols.h> 
        !            43: #import <driverkit/generalFuncs.h>
        !            44: #import <machkit/NXLock.h>
        !            45: #import <bsd/dev/ev_types.h>
        !            46: 
        !            47: #define EVSRC_PRINT    0
        !            48: #if    EVSRC_PRINT
        !            49: #undef xpr_evsrc
        !            50: #define xpr_evsrc(x,a,b,c,d,e) printf(x,a,b,c,d,e)
        !            51: #endif EVSRC_PRINT
        !            52: 
        !            53: #ifndef        xpr_evsrc
        !            54: #define xpr_evsrc(x,a,b,c,d,e)
        !            55: #endif
        !            56: 
        !            57: @implementation IOEventSource: IODevice
        !            58: 
        !            59: + registerEventSource:source
        !            60: {
        !            61:     return [[EventDriver instance] registerEventSource:source];
        !            62: }
        !            63: 
        !            64: /*
        !            65:  * Common EventSrc initialization
        !            66:  */
        !            67: - init
        !            68: {
        !            69:        [super init];
        !            70: 
        !            71:        _owner = nil;
        !            72:        _desiredOwner = nil;
        !            73:        if ( _ownerLock != nil )
        !            74:                [_ownerLock free];
        !            75:        _ownerLock = [NXLock new];
        !            76:        return self;
        !            77: }
        !            78: 
        !            79: - free
        !            80: {
        !            81:        if ( _ownerLock != nil )
        !            82:                [_ownerLock free];
        !            83:        return [super free];
        !            84: }
        !            85: 
        !            86: /*
        !            87:  * Methods used only by subclass.
        !            88:  */
        !            89: - owner
        !            90: {
        !            91:        return _owner;
        !            92: }
        !            93: 
        !            94: - (NXLock *)ownerLock
        !            95: {
        !            96:        return _ownerLock;
        !            97: }
        !            98: 
        !            99: /*
        !           100:  * Exported methods (EventSrcExported protocol).
        !           101:  */
        !           102: 
        !           103: /*
        !           104:  * Register for event dispatch via EventTarget protocol. Returns IO_R_SUCCESS
        !           105:  * if successful, else IO_R_BUSY. The relinquishOwnership: method
        !           106:  * may be called on another client during the execution of this method.
        !           107:  */
        !           108: - (IOReturn)becomeOwner        : client
        !           109: {
        !           110:        IOReturn rtn;
        !           111:        
        !           112:        [_ownerLock lock];
        !           113:        if(_owner != nil) {
        !           114:                xpr_evsrc("%s becomeOwner: NEGOTIATING\n", 
        !           115:                        [self name], 2,3,4,5);
        !           116:                if([_owner respondsTo:@selector(relinquishOwnership:)]) {
        !           117:                        rtn = [_owner relinquishOwnership:self];
        !           118:                }
        !           119:                else {
        !           120:                        IOLog("%s: owner does not respond to "
        !           121:                                "relinquishOwnership:\n", [self name]);
        !           122:                        rtn = IO_R_BUSY;
        !           123:                }
        !           124:                if(rtn == IO_R_SUCCESS) {
        !           125:                        xpr_evsrc("becomeOwner: Transfer ownership\n",
        !           126:                                1,2,3,4,5);
        !           127:                        _owner = client;
        !           128:                }
        !           129:                else {
        !           130:                        xpr_evsrc("becomeOwner: NEGOTIATION FAILED\n",
        !           131:                                1,2,3,4,5);
        !           132:                }
        !           133:        }
        !           134:        else {
        !           135:                _owner = client;
        !           136:                rtn = IO_R_SUCCESS;
        !           137:                xpr_evsrc("%s become owner: SIMPLE CASE\n", 
        !           138:                        [self name], 2,3,4,5);
        !           139:        }
        !           140:        [_ownerLock unlock];
        !           141:        return rtn;
        !           142: }
        !           143: 
        !           144: /*
        !           145:  * Relinquish ownership. Returns IO_R_BUSY if caller is not current owner.
        !           146:  */
        !           147: - (IOReturn)relinquishOwnership        : client
        !           148: {
        !           149:        IOReturn rtn;
        !           150:        
        !           151:        [_ownerLock lock];
        !           152:        if(_owner == client) {
        !           153:                rtn = IO_R_SUCCESS;
        !           154:                _owner = nil;
        !           155:        }
        !           156:        else {
        !           157:                rtn = IO_R_BUSY;
        !           158:        }
        !           159:        [_ownerLock unlock];
        !           160:        if((rtn == IO_R_SUCCESS) && 
        !           161:            _desiredOwner &&
        !           162:            (_desiredOwner != client)) {
        !           163:                /*
        !           164:                 * Notify this potential client that it can take over.
        !           165:                 * We'll most likely be called back during this method,
        !           166:                 * which is why we released _ownerLock.
        !           167:                 */
        !           168:                if([_desiredOwner respondsTo:@selector(canBecomeOwner:)]) {
        !           169:                        xpr_evsrc("%s: notifying %s via canBecomeOwner\n",
        !           170:                                [self name], [_desiredOwner name],
        !           171:                                3,4,5);
        !           172:                        [_desiredOwner canBecomeOwner:self];
        !           173:                }
        !           174:                else {
        !           175:                        IOLog("%s: desiredOwner does not respond to "
        !           176:                                "canBecomeOwner:\n", [self name]);
        !           177:                }
        !           178:        }
        !           179:        xpr_evsrc("%s relinquishOwnership: returning %s\n",
        !           180:                [self name], [self stringFromReturn:rtn], 3,4,5);
        !           181:        return rtn;
        !           182: }
        !           183: 
        !           184: /*
        !           185:  * Register for intent to own upon another owner's relinquishOwnership:.
        !           186:  */
        !           187: - (IOReturn)desireOwnership    : client
        !           188: {
        !           189:        IOReturn rtn;
        !           190:        
        !           191:        [_ownerLock lock];
        !           192:        if(_desiredOwner && (_desiredOwner != client)) {
        !           193:                rtn = IO_R_BUSY;
        !           194:        }
        !           195:        else {
        !           196:                _desiredOwner = client;
        !           197:                rtn = IO_R_SUCCESS;
        !           198:        }
        !           199:        [_ownerLock unlock];
        !           200:        xpr_evsrc("%s desireOwnership: returning %s\n",
        !           201:                [self name], [self stringFromReturn:rtn], 3,4,5);
        !           202:        return rtn;
        !           203:                
        !           204: }
        !           205: 
        !           206: @end
        !           207: 

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