runtime/objc-sel.m

   1 /*
   2  * Copyright (c) 1999 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * Copyright (c) 1999-2003 Apple Computer, Inc.  All Rights Reserved.
   7  *
   8  * This file contains Original Code and/or Modifications of Original Code
   9  * as defined in and that are subject to the Apple Public Source License
  10  * Version 2.0 (the 'License'). You may not use this file except in
  11  * compliance with the License. Please obtain a copy of the License at
  12  * http://www.opensource.apple.com/apsl/ and read it before using this
  13  * file.
  14  *
  15  * The Original Code and all software distributed under the License are
  16  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  17  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  18  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  19  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  20  * Please see the License for the specific language governing rights and
  21  * limitations under the License.
  22  *
  23  * @APPLE_LICENSE_HEADER_END@
  24  */
  25
  26 /*
  27  *      Utilities for registering and looking up selectors.  The sole
  28  *      purpose of the selector tables is a registry whereby there is
  29  *      exactly one address (selector) associated with a given string
  30  *      (method name).
  31  */
  32
  33 #include <objc/objc.h>
  34 #include <CoreFoundation/CFSet.h>
  35 #import "objc-private.h"
  36
  37 // NUM_BUILTIN_SELS, LG_NUM_BUILTIN_SELS, _objc_builtin_selectors
  38 #include "objc-sel-table.h"
  39
  40 #define NUM_NONBUILTIN_SELS 3500
  41 // Panther CFSet grows at 3571, 5778, 9349.
  42 // Most apps use 2000..7000 extra sels. Most apps will grow zero to two times.
  43
  44 static const char *_objc_empty_selector = "";
  45
  46 static SEL _objc_search_builtins(const char *key) {
  47     int c, idx, lg = LG_NUM_BUILTIN_SELS;
  48     const char *s;
  49
  50 #if defined(DUMP_SELECTORS)
  51     if (NULL != key) printf("\t\"%s\",\n", key);
  52 #endif
  53     /* The builtin table contains only sels starting with '[A-z]', including '_' */
  54     if (!key) return (SEL)0;
  55     if ('\0' == *key) return (SEL)_objc_empty_selector;
  56     if (*key < 'A' || 'z' < *key) return (SEL)0;
  57     s = _objc_builtin_selectors[-1 + (1 << lg)];
  58     c = _objc_strcmp(s, key);
  59     if (c == 0) return (SEL)s;
  60     idx = (c < 0) ? NUM_BUILTIN_SELS - (1 << lg) : -1;
  61     while (--lg >= 0) {
  62         s = _objc_builtin_selectors[idx + (1 << lg)];
  63         c = _objc_strcmp(s, key);
  64         if (c == 0) return (SEL)s;
  65         if (c < 0) idx += (1 << lg);
  66     }
  67     return (SEL)0;
  68 }
  69
  70 static OBJC_DECLARE_LOCK(_objc_selector_lock);
  71 static CFMutableSetRef _objc_selectors = NULL;
  72
  73 static Boolean _objc_equal_selector(const void *v1, const void *v2) {
  74     if (v1 == v2) return TRUE;
  75     if ((v1 == NULL) || (v2 == NULL)) return FALSE;
  76     return _objc_strcmp((const unsigned char *)v1, (const unsigned char *)v2) == 0;
  77 }
  78
  79 static CFHashCode _objc_hash_selector(const void *v) {
  80     if (!v) return 0;
  81     return (CFHashCode)_objc_strhash(v);
  82 }
  83
  84 const char *sel_getName(SEL sel) {
  85     return sel ? (const char *)sel : "<null selector>";
  86 }
  87
  88
  89 BOOL sel_isMapped(SEL name) {
  90     SEL result;
  91     const void *value;
  92
  93     if (NULL == name) return NO;
  94     result = _objc_search_builtins((const char *)name);
  95     if ((SEL)0 != result) return YES;
  96     OBJC_LOCK(&_objc_selector_lock);
  97     if (_objc_selectors && CFSetGetValueIfPresent(_objc_selectors, name, &value)) {
  98         result = (SEL)value;
  99     }
 100     OBJC_UNLOCK(&_objc_selector_lock);
 101     return ((SEL)0 != (SEL)result) ? YES : NO;
 102 }
 103
 104 // CoreFoundation private API
 105 extern void _CFSetSetCapacity(CFMutableSetRef set, CFIndex cap);
 106
 107 static SEL __sel_registerName(const char *name, int lockAndCopy) {
 108     SEL result = 0;
 109     const void *value;
 110     if (NULL == name) return (SEL)0;
 111     result = _objc_search_builtins(name);
 112     if ((SEL)0 != result) return result;
 113
 114     if (lockAndCopy) OBJC_LOCK(&_objc_selector_lock);
 115     if (!_objc_selectors || !CFSetGetValueIfPresent(_objc_selectors, name, &value)) {
 116         if (!_objc_selectors) {
 117             CFSetCallBacks cb = {0, NULL, NULL, NULL,
 118                 _objc_equal_selector, _objc_hash_selector};
 119             _objc_selectors = CFSetCreateMutable(kCFAllocatorDefault, 0, &cb);
 120             _CFSetSetCapacity(_objc_selectors, NUM_NONBUILTIN_SELS);
 121             CFSetAddValue(_objc_selectors, (void *)NULL);
 122         }
 123         //if (lockAndCopy > 1) printf("registering %s for sel_getUid\n",name);
 124         value = lockAndCopy ? strdup(name) : name;
 125         CFSetAddValue(_objc_selectors, (void *)value);
 126 #if defined(DUMP_UNKNOWN_SELECTORS)
 127         printf("\t\"%s\",\n", value);
 128 #endif
 129     }
 130     result = (SEL)value;
 131     if (lockAndCopy) OBJC_UNLOCK(&_objc_selector_lock);
 132     return result;
 133 }
 134
 135 SEL sel_registerName(const char *name) {
 136     return __sel_registerName(name, 1);
 137 }
 138
 139 __private_extern__ SEL sel_registerNameNoCopyNoLock(const char *name) {
 140     return __sel_registerName(name, 0);
 141 }
 142
 143 __private_extern__ void sel_lock(void)
 144 {
 145     OBJC_LOCK(&_objc_selector_lock);
 146 }
 147
 148 __private_extern__ void sel_unlock(void)
 149 {
 150     OBJC_UNLOCK(&_objc_selector_lock);
 151 }
 152
 153
 154 // 2001/1/24
 155 // the majority of uses of this function (which used to return NULL if not found)
 156 // did not check for NULL, so, in fact, never return NULL
 157 //
 158 SEL sel_getUid(const char *name) {
 159     return __sel_registerName(name, 2);
 160 }