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111
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1 /* GNU Objective C Runtime class related functions
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131
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2 Copyright (C) 1993-2018 Free Software Foundation, Inc.
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111
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3 Contributed by Kresten Krab Thorup and Dennis Glatting.
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4
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5 Lock-free class table code designed and written from scratch by
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6 Nicola Pero, 2001.
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7
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8 This file is part of GCC.
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9
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10 GCC is free software; you can redistribute it and/or modify it under the
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11 terms of the GNU General Public License as published by the Free Software
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12 Foundation; either version 3, or (at your option) any later version.
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13
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14 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
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15 WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
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16 FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
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17 details.
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18
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19 Under Section 7 of GPL version 3, you are granted additional
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20 permissions described in the GCC Runtime Library Exception, version
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21 3.1, as published by the Free Software Foundation.
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22
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23 You should have received a copy of the GNU General Public License and
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24 a copy of the GCC Runtime Library Exception along with this program;
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25 see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
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26 <http://www.gnu.org/licenses/>. */
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27
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28 /* The code in this file critically affects class method invocation
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29 speed. This long preamble comment explains why, and the issues
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30 involved.
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31
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32 One of the traditional weaknesses of the GNU Objective-C runtime is
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33 that class method invocations are slow. The reason is that when you
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34 write
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35
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36 array = [NSArray new];
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37
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38 this gets basically compiled into the equivalent of
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39
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40 array = [(objc_get_class ("NSArray")) new];
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41
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42 objc_get_class returns the class pointer corresponding to the string
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43 `NSArray'; and because of the lookup, the operation is more
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44 complicated and slow than a simple instance method invocation.
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45
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46 Most high performance Objective-C code (using the GNU Objc runtime)
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47 I had the opportunity to read (or write) work around this problem by
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48 caching the class pointer:
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49
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50 Class arrayClass = [NSArray class];
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51
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52 ... later on ...
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53
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54 array = [arrayClass new];
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55 array = [arrayClass new];
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56 array = [arrayClass new];
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57
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58 In this case, you always perform a class lookup (the first one), but
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59 then all the [arrayClass new] methods run exactly as fast as an
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60 instance method invocation. It helps if you have many class method
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61 invocations to the same class.
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62
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63 The long-term solution to this problem would be to modify the
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64 compiler to output tables of class pointers corresponding to all the
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65 class method invocations, and to add code to the runtime to update
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66 these tables - that should in the end allow class method invocations
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67 to perform precisely as fast as instance method invocations, because
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68 no class lookup would be involved. I think the Apple Objective-C
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69 runtime uses this technique. Doing this involves synchronized
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70 modifications in the runtime and in the compiler.
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71
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72 As a first medicine to the problem, I [NP] have redesigned and
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73 rewritten the way the runtime is performing class lookup. This
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74 doesn't give as much speed as the other (definitive) approach, but
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75 at least a class method invocation now takes approximately 4.5 times
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76 an instance method invocation on my machine (it would take approx 12
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77 times before the rewriting), which is a lot better.
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78
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79 One of the main reason the new class lookup is so faster is because
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80 I implemented it in a way that can safely run multithreaded without
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81 using locks - a so-called `lock-free' data structure. The atomic
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82 operation is pointer assignment. The reason why in this problem
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83 lock-free data structures work so well is that you never remove
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84 classes from the table - and the difficult thing with lock-free data
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85 structures is freeing data when is removed from the structures. */
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86
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87 #include "objc-private/common.h"
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88 #include "objc-private/error.h"
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89 #include "objc/runtime.h"
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90 #include "objc/thr.h"
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91 #include "objc-private/module-abi-8.h" /* For CLS_ISCLASS and similar. */
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92 #include "objc-private/runtime.h" /* the kitchen sink */
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93 #include "objc-private/sarray.h" /* For sarray_put_at_safe. */
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94 #include "objc-private/selector.h" /* For sarray_put_at_safe. */
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95 #include <string.h> /* For memset */
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96
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97 /* We use a table which maps a class name to the corresponding class
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98 pointer. The first part of this file defines this table, and
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99 functions to do basic operations on the table. The second part of
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100 the file implements some higher level Objective-C functionality for
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101 classes by using the functions provided in the first part to manage
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102 the table. */
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103
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104 /**
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105 ** Class Table Internals
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106 **/
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107
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108 /* A node holding a class */
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109 typedef struct class_node
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110 {
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111 struct class_node *next; /* Pointer to next entry on the list.
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112 NULL indicates end of list. */
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113
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114 const char *name; /* The class name string */
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115 int length; /* The class name string length */
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116 Class pointer; /* The Class pointer */
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117
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118 } *class_node_ptr;
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119
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120 /* A table containing classes is a class_node_ptr (pointing to the
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121 first entry in the table - if it is NULL, then the table is
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122 empty). */
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123
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124 /* We have 1024 tables. Each table contains all class names which
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125 have the same hash (which is a number between 0 and 1023). To look
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126 up a class_name, we compute its hash, and get the corresponding
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127 table. Once we have the table, we simply compare strings directly
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128 till we find the one which we want (using the length first). The
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129 number of tables is quite big on purpose (a normal big application
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130 has less than 1000 classes), so that you shouldn't normally get any
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131 collisions, and get away with a single comparison (which we can't
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132 avoid since we need to know that you have got the right thing). */
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133 #define CLASS_TABLE_SIZE 1024
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134 #define CLASS_TABLE_MASK 1023
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135
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136 static class_node_ptr class_table_array[CLASS_TABLE_SIZE];
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137
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138 /* The table writing mutex - we lock on writing to avoid conflicts
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139 between different writers, but we read without locks. That is
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140 possible because we assume pointer assignment to be an atomic
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141 operation. TODO: This is only true under certain circumstances,
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142 which should be clarified. */
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143 static objc_mutex_t __class_table_lock = NULL;
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144
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145 /* CLASS_TABLE_HASH is how we compute the hash of a class name. It is
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146 a macro - *not* a function - arguments *are* modified directly.
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147
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148 INDEX should be a variable holding an int;
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149 HASH should be a variable holding an int;
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150 CLASS_NAME should be a variable holding a (char *) to the class_name.
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151
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152 After the macro is executed, INDEX contains the length of the
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153 string, and HASH the computed hash of the string; CLASS_NAME is
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154 untouched. */
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155
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131
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156 #define CLASS_TABLE_HASH(INDEX, HASH, CLASS_NAME) \
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157 do { \
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158 HASH = 0; \
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159 for (INDEX = 0; CLASS_NAME[INDEX] != '\0'; INDEX++) \
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160 { \
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161 HASH = (HASH << 4) ^ (HASH >> 28) ^ CLASS_NAME[INDEX]; \
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162 } \
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163 \
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164 HASH = (HASH ^ (HASH >> 10) ^ (HASH >> 20)) & CLASS_TABLE_MASK; \
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165 } while (0)
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111
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166
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167 /* Setup the table. */
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168 static void
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169 class_table_setup (void)
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170 {
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171 /* Start - nothing in the table. */
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172 memset (class_table_array, 0, sizeof (class_node_ptr) * CLASS_TABLE_SIZE);
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173
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174 /* The table writing mutex. */
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175 __class_table_lock = objc_mutex_allocate ();
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176 }
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177
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178
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179 /* Insert a class in the table (used when a new class is
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180 registered). */
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181 static void
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182 class_table_insert (const char *class_name, Class class_pointer)
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183 {
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184 int hash, length;
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185 class_node_ptr new_node;
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186
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187 /* Find out the class name's hash and length. */
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188 CLASS_TABLE_HASH (length, hash, class_name);
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189
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190 /* Prepare the new node holding the class. */
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191 new_node = objc_malloc (sizeof (struct class_node));
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192 new_node->name = class_name;
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193 new_node->length = length;
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194 new_node->pointer = class_pointer;
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195
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196 /* Lock the table for modifications. */
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197 objc_mutex_lock (__class_table_lock);
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198
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199 /* Insert the new node in the table at the beginning of the table at
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200 class_table_array[hash]. */
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201 new_node->next = class_table_array[hash];
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202 class_table_array[hash] = new_node;
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203
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204 objc_mutex_unlock (__class_table_lock);
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205 }
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206
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207 /* Get a class from the table. This does not need mutex protection.
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208 Currently, this function is called each time you call a static
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209 method, this is why it must be very fast. */
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210 static inline Class
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211 class_table_get_safe (const char *class_name)
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212 {
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213 class_node_ptr node;
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214 int length, hash;
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215
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216 /* Compute length and hash. */
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217 CLASS_TABLE_HASH (length, hash, class_name);
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218
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219 node = class_table_array[hash];
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220
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221 if (node != NULL)
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222 {
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223 do
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224 {
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225 if (node->length == length)
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226 {
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227 /* Compare the class names. */
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228 int i;
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229
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230 for (i = 0; i < length; i++)
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231 {
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232 if ((node->name)[i] != class_name[i])
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233 break;
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234 }
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235
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236 if (i == length)
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237 {
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238 /* They are equal! */
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239 return node->pointer;
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240 }
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241 }
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242 }
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243 while ((node = node->next) != NULL);
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244 }
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245
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246 return Nil;
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247 }
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248
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249 /* Enumerate over the class table. */
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250 struct class_table_enumerator
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251 {
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252 int hash;
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253 class_node_ptr node;
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254 };
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255
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256
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257 static Class
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258 class_table_next (struct class_table_enumerator **e)
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259 {
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260 struct class_table_enumerator *enumerator = *e;
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261 class_node_ptr next;
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262
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263 if (enumerator == NULL)
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264 {
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265 *e = objc_malloc (sizeof (struct class_table_enumerator));
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266 enumerator = *e;
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267 enumerator->hash = 0;
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268 enumerator->node = NULL;
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269
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270 next = class_table_array[enumerator->hash];
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271 }
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272 else
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273 next = enumerator->node->next;
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274
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275 if (next != NULL)
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276 {
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277 enumerator->node = next;
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278 return enumerator->node->pointer;
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279 }
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280 else
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281 {
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282 enumerator->hash++;
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283
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284 while (enumerator->hash < CLASS_TABLE_SIZE)
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285 {
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286 next = class_table_array[enumerator->hash];
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287 if (next != NULL)
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288 {
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289 enumerator->node = next;
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290 return enumerator->node->pointer;
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291 }
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292 enumerator->hash++;
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293 }
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294
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295 /* Ok - table finished - done. */
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296 objc_free (enumerator);
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297 return Nil;
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298 }
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299 }
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300
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301 #if 0 /* DEBUGGING FUNCTIONS */
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302 /* Debugging function - print the class table. */
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303 void
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304 class_table_print (void)
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305 {
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306 int i;
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307
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308 for (i = 0; i < CLASS_TABLE_SIZE; i++)
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309 {
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310 class_node_ptr node;
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311
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312 printf ("%d:\n", i);
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313 node = class_table_array[i];
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314
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315 while (node != NULL)
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316 {
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317 printf ("\t%s\n", node->name);
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318 node = node->next;
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319 }
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320 }
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321 }
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322
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323 /* Debugging function - print an histogram of number of classes in
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324 function of hash key values. Useful to evaluate the hash function
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325 in real cases. */
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326 void
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327 class_table_print_histogram (void)
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328 {
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329 int i, j;
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330 int counter = 0;
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331
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332 for (i = 0; i < CLASS_TABLE_SIZE; i++)
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333 {
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334 class_node_ptr node;
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335
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336 node = class_table_array[i];
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337
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338 while (node != NULL)
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339 {
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340 counter++;
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341 node = node->next;
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342 }
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343 if (((i + 1) % 50) == 0)
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344 {
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345 printf ("%4d:", i + 1);
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346 for (j = 0; j < counter; j++)
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347 printf ("X");
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348
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349 printf ("\n");
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350 counter = 0;
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351 }
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352 }
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353 printf ("%4d:", i + 1);
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354 for (j = 0; j < counter; j++)
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355 printf ("X");
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356
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357 printf ("\n");
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358 }
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359 #endif /* DEBUGGING FUNCTIONS */
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360
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361 /**
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362 ** Objective-C runtime functions
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363 **/
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364
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365 /* From now on, the only access to the class table data structure
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366 should be via the class_table_* functions. */
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367
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368 /* This is a hook which is called by objc_get_class and
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369 objc_lookup_class if the runtime is not able to find the class.
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370 This may e.g. try to load in the class using dynamic loading.
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371
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372 This hook was a public, global variable in the Traditional GNU
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373 Objective-C Runtime API (objc/objc-api.h). The modern GNU
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374 Objective-C Runtime API (objc/runtime.h) provides the
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375 objc_setGetUnknownClassHandler() function instead.
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376 */
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377 Class (*_objc_lookup_class) (const char *name) = 0; /* !T:SAFE */
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378
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379 /* The handler currently in use. PS: if both
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380 __obj_get_unknown_class_handler and _objc_lookup_class are defined,
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381 __objc_get_unknown_class_handler is called first. */
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382 static objc_get_unknown_class_handler
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383 __objc_get_unknown_class_handler = NULL;
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384
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385 objc_get_unknown_class_handler
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386 objc_setGetUnknownClassHandler (objc_get_unknown_class_handler
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387 new_handler)
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388 {
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389 objc_get_unknown_class_handler old_handler
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390 = __objc_get_unknown_class_handler;
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391 __objc_get_unknown_class_handler = new_handler;
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392 return old_handler;
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393 }
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394
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395
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396 /* True when class links has been resolved. */
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397 BOOL __objc_class_links_resolved = NO; /* !T:UNUSED */
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398
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399
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400 void
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401 __objc_init_class_tables (void)
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402 {
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403 /* Allocate the class hash table. */
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404
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405 if (__class_table_lock)
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406 return;
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407
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408 objc_mutex_lock (__objc_runtime_mutex);
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409
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410 class_table_setup ();
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411
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412 objc_mutex_unlock (__objc_runtime_mutex);
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413 }
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414
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415 /* This function adds a class to the class hash table, and assigns the
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416 class a number, unless it's already known. Return 'YES' if the
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417 class was added. Return 'NO' if the class was already known. */
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418 BOOL
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419 __objc_add_class_to_hash (Class class)
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420 {
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421 Class existing_class;
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422
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423 objc_mutex_lock (__objc_runtime_mutex);
|
|
|
424
|
|
|
425 /* Make sure the table is there. */
|
|
|
426 assert (__class_table_lock);
|
|
|
427
|
|
|
428 /* Make sure it's not a meta class. */
|
|
|
429 assert (CLS_ISCLASS (class));
|
|
|
430
|
|
|
431 /* Check to see if the class is already in the hash table. */
|
|
|
432 existing_class = class_table_get_safe (class->name);
|
|
|
433
|
|
|
434 if (existing_class)
|
|
|
435 {
|
|
|
436 objc_mutex_unlock (__objc_runtime_mutex);
|
|
|
437 return NO;
|
|
|
438 }
|
|
|
439 else
|
|
|
440 {
|
|
|
441 /* The class isn't in the hash table. Add the class and assign
|
|
|
442 a class number. */
|
|
|
443 static unsigned int class_number = 1;
|
|
|
444
|
|
|
445 CLS_SETNUMBER (class, class_number);
|
|
|
446 CLS_SETNUMBER (class->class_pointer, class_number);
|
|
|
447
|
|
|
448 ++class_number;
|
|
|
449 class_table_insert (class->name, class);
|
|
|
450
|
|
|
451 objc_mutex_unlock (__objc_runtime_mutex);
|
|
|
452 return YES;
|
|
|
453 }
|
|
|
454 }
|
|
|
455
|
|
|
456 Class
|
|
|
457 objc_getClass (const char *name)
|
|
|
458 {
|
|
|
459 Class class;
|
|
|
460
|
|
|
461 if (name == NULL)
|
|
|
462 return Nil;
|
|
|
463
|
|
|
464 class = class_table_get_safe (name);
|
|
|
465
|
|
|
466 if (class)
|
|
|
467 return class;
|
|
|
468
|
|
|
469 if (__objc_get_unknown_class_handler)
|
|
|
470 return (*__objc_get_unknown_class_handler) (name);
|
|
|
471
|
|
|
472 if (_objc_lookup_class)
|
|
|
473 return (*_objc_lookup_class) (name);
|
|
|
474
|
|
|
475 return Nil;
|
|
|
476 }
|
|
|
477
|
|
|
478 Class
|
|
|
479 objc_lookUpClass (const char *name)
|
|
|
480 {
|
|
|
481 if (name == NULL)
|
|
|
482 return Nil;
|
|
|
483 else
|
|
|
484 return class_table_get_safe (name);
|
|
|
485 }
|
|
|
486
|
|
|
487 Class
|
|
|
488 objc_getMetaClass (const char *name)
|
|
|
489 {
|
|
|
490 Class class = objc_getClass (name);
|
|
|
491
|
|
|
492 if (class)
|
|
|
493 return class->class_pointer;
|
|
|
494 else
|
|
|
495 return Nil;
|
|
|
496 }
|
|
|
497
|
|
|
498 Class
|
|
|
499 objc_getRequiredClass (const char *name)
|
|
|
500 {
|
|
|
501 Class class = objc_getClass (name);
|
|
|
502
|
|
|
503 if (class)
|
|
|
504 return class;
|
|
|
505 else
|
|
|
506 _objc_abort ("objc_getRequiredClass ('%s') failed: class not found\n", name);
|
|
|
507 }
|
|
|
508
|
|
|
509 int
|
|
|
510 objc_getClassList (Class *returnValue, int maxNumberOfClassesToReturn)
|
|
|
511 {
|
|
|
512 /* Iterate over all entries in the table. */
|
|
|
513 int hash, count = 0;
|
|
|
514
|
|
|
515 for (hash = 0; hash < CLASS_TABLE_SIZE; hash++)
|
|
|
516 {
|
|
|
517 class_node_ptr node = class_table_array[hash];
|
|
|
518
|
|
|
519 while (node != NULL)
|
|
|
520 {
|
|
|
521 if (returnValue)
|
|
|
522 {
|
|
|
523 if (count < maxNumberOfClassesToReturn)
|
|
|
524 returnValue[count] = node->pointer;
|
|
|
525 else
|
|
|
526 return count;
|
|
|
527 }
|
|
|
528 count++;
|
|
|
529 node = node->next;
|
|
|
530 }
|
|
|
531 }
|
|
|
532
|
|
|
533 return count;
|
|
|
534 }
|
|
|
535
|
|
|
536 Class
|
|
|
537 objc_allocateClassPair (Class super_class, const char *class_name, size_t extraBytes)
|
|
|
538 {
|
|
|
539 Class new_class;
|
|
|
540 Class new_meta_class;
|
|
|
541
|
|
|
542 if (class_name == NULL)
|
|
|
543 return Nil;
|
|
|
544
|
|
|
545 if (objc_getClass (class_name))
|
|
|
546 return Nil;
|
|
|
547
|
|
|
548 if (super_class)
|
|
|
549 {
|
|
|
550 /* If you want to build a hierarchy of classes, you need to
|
|
|
551 build and register them one at a time. The risk is that you
|
|
|
552 are able to cause confusion by registering a subclass before
|
|
|
553 the superclass or similar. */
|
|
|
554 if (CLS_IS_IN_CONSTRUCTION (super_class))
|
|
|
555 return Nil;
|
|
|
556 }
|
|
|
557
|
|
|
558 /* Technically, we should create the metaclass first, then use
|
|
|
559 class_createInstance() to create the class. That complication
|
|
|
560 would be relevant if we had class variables, but we don't, so we
|
|
|
561 just ignore it and create everything directly and assume all
|
|
|
562 classes have the same size. */
|
|
|
563 new_class = objc_calloc (1, sizeof (struct objc_class) + extraBytes);
|
|
|
564 new_meta_class = objc_calloc (1, sizeof (struct objc_class) + extraBytes);
|
|
|
565
|
|
|
566 /* We create an unresolved class, similar to one generated by the
|
|
|
567 compiler. It will be resolved later when we register it.
|
|
|
568
|
|
|
569 Note how the metaclass details are not that important; when the
|
|
|
570 class is resolved, the ones that matter will be fixed up. */
|
|
|
571 new_class->class_pointer = new_meta_class;
|
|
|
572 new_meta_class->class_pointer = 0;
|
|
|
573
|
|
|
574 if (super_class)
|
|
|
575 {
|
|
|
576 /* Force the name of the superclass in place of the link to the
|
|
|
577 actual superclass, which will be put there when the class is
|
|
|
578 resolved. */
|
|
|
579 const char *super_class_name = class_getName (super_class);
|
|
|
580 new_class->super_class = (void *)super_class_name;
|
|
|
581 new_meta_class->super_class = (void *)super_class_name;
|
|
|
582 }
|
|
|
583 else
|
|
|
584 {
|
|
|
585 new_class->super_class = (void *)0;
|
|
|
586 new_meta_class->super_class = (void *)0;
|
|
|
587 }
|
|
|
588
|
|
|
589 new_class->name = objc_malloc (strlen (class_name) + 1);
|
|
|
590 strcpy ((char*)new_class->name, class_name);
|
|
|
591 new_meta_class->name = new_class->name;
|
|
|
592
|
|
|
593 new_class->version = 0;
|
|
|
594 new_meta_class->version = 0;
|
|
|
595
|
|
|
596 new_class->info = _CLS_CLASS | _CLS_IN_CONSTRUCTION;
|
|
|
597 new_meta_class->info = _CLS_META | _CLS_IN_CONSTRUCTION;
|
|
|
598
|
|
|
599 if (super_class)
|
|
|
600 new_class->instance_size = super_class->instance_size;
|
|
|
601 else
|
|
|
602 new_class->instance_size = 0;
|
|
|
603 new_meta_class->instance_size = sizeof (struct objc_class);
|
|
|
604
|
|
|
605 return new_class;
|
|
|
606 }
|
|
|
607
|
|
|
608 void
|
|
|
609 objc_registerClassPair (Class class_)
|
|
|
610 {
|
|
|
611 if (class_ == Nil)
|
|
|
612 return;
|
|
|
613
|
|
|
614 if ((! CLS_ISCLASS (class_)) || (! CLS_IS_IN_CONSTRUCTION (class_)))
|
|
|
615 return;
|
|
|
616
|
|
|
617 if ((! CLS_ISMETA (class_->class_pointer)) || (! CLS_IS_IN_CONSTRUCTION (class_->class_pointer)))
|
|
|
618 return;
|
|
|
619
|
|
|
620 objc_mutex_lock (__objc_runtime_mutex);
|
|
|
621
|
|
|
622 if (objc_getClass (class_->name))
|
|
|
623 {
|
|
|
624 objc_mutex_unlock (__objc_runtime_mutex);
|
|
|
625 return;
|
|
|
626 }
|
|
|
627
|
|
|
628 CLS_SET_NOT_IN_CONSTRUCTION (class_);
|
|
|
629 CLS_SET_NOT_IN_CONSTRUCTION (class_->class_pointer);
|
|
|
630
|
|
|
631 __objc_init_class (class_);
|
|
|
632
|
|
|
633 /* Resolve class links immediately. No point in waiting. */
|
|
|
634 __objc_resolve_class_links ();
|
|
|
635
|
|
|
636 objc_mutex_unlock (__objc_runtime_mutex);
|
|
|
637 }
|
|
|
638
|
|
|
639 void
|
|
|
640 objc_disposeClassPair (Class class_)
|
|
|
641 {
|
|
|
642 if (class_ == Nil)
|
|
|
643 return;
|
|
|
644
|
|
|
645 if ((! CLS_ISCLASS (class_)) || (! CLS_IS_IN_CONSTRUCTION (class_)))
|
|
|
646 return;
|
|
|
647
|
|
|
648 if ((! CLS_ISMETA (class_->class_pointer)) || (! CLS_IS_IN_CONSTRUCTION (class_->class_pointer)))
|
|
|
649 return;
|
|
|
650
|
|
|
651 /* Undo any class_addIvar(). */
|
|
|
652 if (class_->ivars)
|
|
|
653 {
|
|
|
654 int i;
|
|
|
655 for (i = 0; i < class_->ivars->ivar_count; i++)
|
|
|
656 {
|
|
|
657 struct objc_ivar *ivar = &(class_->ivars->ivar_list[i]);
|
|
|
658
|
|
|
659 objc_free ((char *)ivar->ivar_name);
|
|
|
660 objc_free ((char *)ivar->ivar_type);
|
|
|
661 }
|
|
|
662
|
|
|
663 objc_free (class_->ivars);
|
|
|
664 }
|
|
|
665
|
|
|
666 /* Undo any class_addMethod(). */
|
|
|
667 if (class_->methods)
|
|
|
668 {
|
|
|
669 struct objc_method_list *list = class_->methods;
|
|
|
670 while (list)
|
|
|
671 {
|
|
|
672 int i;
|
|
|
673 struct objc_method_list *next = list->method_next;
|
|
|
674
|
|
|
675 for (i = 0; i < list->method_count; i++)
|
|
|
676 {
|
|
|
677 struct objc_method *method = &(list->method_list[i]);
|
|
|
678
|
|
|
679 objc_free ((char *)method->method_name);
|
|
|
680 objc_free ((char *)method->method_types);
|
|
|
681 }
|
|
|
682
|
|
|
683 objc_free (list);
|
|
|
684 list = next;
|
|
|
685 }
|
|
|
686 }
|
|
|
687
|
|
|
688 /* Undo any class_addProtocol(). */
|
|
|
689 if (class_->protocols)
|
|
|
690 {
|
|
|
691 struct objc_protocol_list *list = class_->protocols;
|
|
|
692 while (list)
|
|
|
693 {
|
|
|
694 struct objc_protocol_list *next = list->next;
|
|
|
695
|
|
|
696 objc_free (list);
|
|
|
697 list = next;
|
|
|
698 }
|
|
|
699 }
|
|
|
700
|
|
|
701 /* Undo any class_addMethod() on the meta-class. */
|
|
|
702 if (class_->class_pointer->methods)
|
|
|
703 {
|
|
|
704 struct objc_method_list *list = class_->class_pointer->methods;
|
|
|
705 while (list)
|
|
|
706 {
|
|
|
707 int i;
|
|
|
708 struct objc_method_list *next = list->method_next;
|
|
|
709
|
|
|
710 for (i = 0; i < list->method_count; i++)
|
|
|
711 {
|
|
|
712 struct objc_method *method = &(list->method_list[i]);
|
|
|
713
|
|
|
714 objc_free ((char *)method->method_name);
|
|
|
715 objc_free ((char *)method->method_types);
|
|
|
716 }
|
|
|
717
|
|
|
718 objc_free (list);
|
|
|
719 list = next;
|
|
|
720 }
|
|
|
721 }
|
|
|
722
|
|
|
723 /* Undo objc_allocateClassPair(). */
|
|
|
724 objc_free ((char *)(class_->name));
|
|
|
725 objc_free (class_->class_pointer);
|
|
|
726 objc_free (class_);
|
|
|
727 }
|
|
|
728
|
|
|
729 /* Traditional GNU Objective-C Runtime API. Important: this method is
|
|
|
730 called automatically by the compiler while messaging (if using the
|
|
|
731 traditional ABI), so it is worth keeping it fast; don't make it
|
|
|
732 just a wrapper around objc_getClass(). */
|
|
|
733 /* Note that this is roughly equivalent to objc_getRequiredClass(). */
|
|
|
734 /* Get the class object for the class named NAME. If NAME does not
|
|
|
735 identify a known class, the hook _objc_lookup_class is called. If
|
|
|
736 this fails, an error message is issued and the system aborts. */
|
|
|
737 Class
|
|
|
738 objc_get_class (const char *name)
|
|
|
739 {
|
|
|
740 Class class;
|
|
|
741
|
|
|
742 class = class_table_get_safe (name);
|
|
|
743
|
|
|
744 if (class)
|
|
|
745 return class;
|
|
|
746
|
|
|
747 if (__objc_get_unknown_class_handler)
|
|
|
748 class = (*__objc_get_unknown_class_handler) (name);
|
|
|
749
|
|
|
750 if ((!class) && _objc_lookup_class)
|
|
|
751 class = (*_objc_lookup_class) (name);
|
|
|
752
|
|
|
753 if (class)
|
|
|
754 return class;
|
|
|
755
|
|
|
756 _objc_abort ("objc runtime: cannot find class %s\n", name);
|
|
|
757
|
|
|
758 return 0;
|
|
|
759 }
|
|
|
760
|
|
|
761 /* This is used by the compiler too. */
|
|
|
762 Class
|
|
|
763 objc_get_meta_class (const char *name)
|
|
|
764 {
|
|
|
765 return objc_get_class (name)->class_pointer;
|
|
|
766 }
|
|
|
767
|
|
|
768 /* This is not used by GCC, but the clang compiler seems to use it
|
|
|
769 when targeting the GNU runtime. That's wrong, but we have it to
|
|
|
770 be compatible. */
|
|
|
771 Class
|
|
|
772 objc_lookup_class (const char *name)
|
|
|
773 {
|
|
|
774 return objc_getClass (name);
|
|
|
775 }
|
|
|
776
|
|
|
777 /* This is used when the implementation of a method changes. It goes
|
|
|
778 through all classes, looking for the ones that have these methods
|
|
|
779 (either method_a or method_b; method_b can be NULL), and reloads
|
|
|
780 the implementation for these. You should call this with the
|
|
|
781 runtime mutex already locked. */
|
|
|
782 void
|
|
|
783 __objc_update_classes_with_methods (struct objc_method *method_a, struct objc_method *method_b)
|
|
|
784 {
|
|
|
785 int hash;
|
|
|
786
|
|
|
787 /* Iterate over all classes. */
|
|
|
788 for (hash = 0; hash < CLASS_TABLE_SIZE; hash++)
|
|
|
789 {
|
|
|
790 class_node_ptr node = class_table_array[hash];
|
|
|
791
|
|
|
792 while (node != NULL)
|
|
|
793 {
|
|
|
794 /* We execute this loop twice: the first time, we iterate
|
|
|
795 over all methods in the class (instance methods), while
|
|
|
796 the second time we iterate over all methods in the meta
|
|
|
797 class (class methods). */
|
|
|
798 Class class = Nil;
|
|
|
799 BOOL done = NO;
|
|
|
800
|
|
|
801 while (done == NO)
|
|
|
802 {
|
|
|
803 struct objc_method_list * method_list;
|
|
|
804
|
|
|
805 if (class == Nil)
|
|
|
806 {
|
|
|
807 /* The first time, we work on the class. */
|
|
|
808 class = node->pointer;
|
|
|
809 }
|
|
|
810 else
|
|
|
811 {
|
|
|
812 /* The second time, we work on the meta class. */
|
|
|
813 class = class->class_pointer;
|
|
|
814 done = YES;
|
|
|
815 }
|
|
|
816
|
|
|
817 method_list = class->methods;
|
|
|
818
|
|
|
819 while (method_list)
|
|
|
820 {
|
|
|
821 int i;
|
|
|
822
|
|
|
823 for (i = 0; i < method_list->method_count; ++i)
|
|
|
824 {
|
|
|
825 struct objc_method *method = &method_list->method_list[i];
|
|
|
826
|
|
|
827 /* If the method is one of the ones we are
|
|
|
828 looking for, update the implementation. */
|
|
|
829 if (method == method_a)
|
|
|
830 sarray_at_put_safe (class->dtable,
|
|
|
831 (sidx) method_a->method_name->sel_id,
|
|
|
832 method_a->method_imp);
|
|
|
833
|
|
|
834 if (method == method_b)
|
|
|
835 {
|
|
|
836 if (method_b != NULL)
|
|
|
837 sarray_at_put_safe (class->dtable,
|
|
|
838 (sidx) method_b->method_name->sel_id,
|
|
|
839 method_b->method_imp);
|
|
|
840 }
|
|
|
841 }
|
|
|
842
|
|
|
843 method_list = method_list->method_next;
|
|
|
844 }
|
|
|
845 }
|
|
|
846 node = node->next;
|
|
|
847 }
|
|
|
848 }
|
|
|
849 }
|
|
|
850
|
|
|
851 /* Resolve super/subclass links for all classes. The only thing we
|
|
|
852 can be sure of is that the class_pointer for class objects point to
|
|
|
853 the right meta class objects. */
|
|
|
854 void
|
|
|
855 __objc_resolve_class_links (void)
|
|
|
856 {
|
|
|
857 struct class_table_enumerator *es = NULL;
|
|
|
858 Class object_class = objc_get_class ("Object");
|
|
|
859 Class class1;
|
|
|
860
|
|
|
861 assert (object_class);
|
|
|
862
|
|
|
863 objc_mutex_lock (__objc_runtime_mutex);
|
|
|
864
|
|
|
865 /* Assign subclass links. */
|
|
|
866 while ((class1 = class_table_next (&es)))
|
|
|
867 {
|
|
|
868 /* Make sure we have what we think we have. */
|
|
|
869 assert (CLS_ISCLASS (class1));
|
|
|
870 assert (CLS_ISMETA (class1->class_pointer));
|
|
|
871
|
|
|
872 /* The class_pointer of all meta classes point to Object's meta
|
|
|
873 class. */
|
|
|
874 class1->class_pointer->class_pointer = object_class->class_pointer;
|
|
|
875
|
|
|
876 if (! CLS_ISRESOLV (class1))
|
|
|
877 {
|
|
|
878 CLS_SETRESOLV (class1);
|
|
|
879 CLS_SETRESOLV (class1->class_pointer);
|
|
|
880
|
|
|
881 if (class1->super_class)
|
|
|
882 {
|
|
|
883 Class a_super_class
|
|
|
884 = objc_get_class ((char *) class1->super_class);
|
|
|
885
|
|
|
886 assert (a_super_class);
|
|
|
887
|
|
|
888 DEBUG_PRINTF ("making class connections for: %s\n",
|
|
|
889 class1->name);
|
|
|
890
|
|
|
891 /* Assign subclass links for superclass. */
|
|
|
892 class1->sibling_class = a_super_class->subclass_list;
|
|
|
893 a_super_class->subclass_list = class1;
|
|
|
894
|
|
|
895 /* Assign subclass links for meta class of superclass. */
|
|
|
896 if (a_super_class->class_pointer)
|
|
|
897 {
|
|
|
898 class1->class_pointer->sibling_class
|
|
|
899 = a_super_class->class_pointer->subclass_list;
|
|
|
900 a_super_class->class_pointer->subclass_list
|
|
|
901 = class1->class_pointer;
|
|
|
902 }
|
|
|
903 }
|
|
|
904 else /* A root class, make its meta object be a subclass of
|
|
|
905 Object. */
|
|
|
906 {
|
|
|
907 class1->class_pointer->sibling_class
|
|
|
908 = object_class->subclass_list;
|
|
|
909 object_class->subclass_list = class1->class_pointer;
|
|
|
910 }
|
|
|
911 }
|
|
|
912 }
|
|
|
913
|
|
|
914 /* Assign superclass links. */
|
|
|
915 es = NULL;
|
|
|
916 while ((class1 = class_table_next (&es)))
|
|
|
917 {
|
|
|
918 Class sub_class;
|
|
|
919 for (sub_class = class1->subclass_list; sub_class;
|
|
|
920 sub_class = sub_class->sibling_class)
|
|
|
921 {
|
|
|
922 sub_class->super_class = class1;
|
|
|
923 if (CLS_ISCLASS (sub_class))
|
|
|
924 sub_class->class_pointer->super_class = class1->class_pointer;
|
|
|
925 }
|
|
|
926 }
|
|
|
927
|
|
|
928 objc_mutex_unlock (__objc_runtime_mutex);
|
|
|
929 }
|
|
|
930
|
|
|
931 const char *
|
|
|
932 class_getName (Class class_)
|
|
|
933 {
|
|
|
934 if (class_ == Nil)
|
|
|
935 return "nil";
|
|
|
936
|
|
|
937 return class_->name;
|
|
|
938 }
|
|
|
939
|
|
|
940 BOOL
|
|
|
941 class_isMetaClass (Class class_)
|
|
|
942 {
|
|
|
943 /* CLS_ISMETA includes the check for Nil class_. */
|
|
|
944 return CLS_ISMETA (class_);
|
|
|
945 }
|
|
|
946
|
|
|
947 /* Even inside libobjc it may be worth using class_getSuperclass
|
|
|
948 instead of accessing class_->super_class directly because it
|
|
|
949 resolves the class links if needed. If you access
|
|
|
950 class_->super_class directly, make sure to deal with the situation
|
|
|
951 where the class is not resolved yet! */
|
|
|
952 Class
|
|
|
953 class_getSuperclass (Class class_)
|
|
|
954 {
|
|
|
955 if (class_ == Nil)
|
|
|
956 return Nil;
|
|
|
957
|
|
|
958 /* Classes that are in construction are not resolved, and still have
|
|
|
959 the class name (instead of a class pointer) in the
|
|
|
960 class_->super_class field. In that case we need to lookup the
|
|
|
961 superclass name to return the superclass. We can not resolve the
|
|
|
962 class until it is registered. */
|
|
|
963 if (CLS_IS_IN_CONSTRUCTION (class_))
|
|
|
964 {
|
|
|
965 if (CLS_ISMETA (class_))
|
|
|
966 return object_getClass ((id)objc_lookUpClass ((const char *)(class_->super_class)));
|
|
|
967 else
|
|
|
968 return objc_lookUpClass ((const char *)(class_->super_class));
|
|
|
969 }
|
|
|
970
|
|
|
971 /* If the class is not resolved yet, super_class would point to a
|
|
|
972 string (the name of the super class) as opposed to the actual
|
|
|
973 super class. In that case, we need to resolve the class links
|
|
|
974 before we can return super_class. */
|
|
|
975 if (! CLS_ISRESOLV (class_))
|
|
|
976 __objc_resolve_class_links ();
|
|
|
977
|
|
|
978 return class_->super_class;
|
|
|
979 }
|
|
|
980
|
|
|
981 int
|
|
|
982 class_getVersion (Class class_)
|
|
|
983 {
|
|
|
984 if (class_ == Nil)
|
|
|
985 return 0;
|
|
|
986
|
|
|
987 return (int)(class_->version);
|
|
|
988 }
|
|
|
989
|
|
|
990 void
|
|
|
991 class_setVersion (Class class_, int version)
|
|
|
992 {
|
|
|
993 if (class_ == Nil)
|
|
|
994 return;
|
|
|
995
|
|
|
996 class_->version = version;
|
|
|
997 }
|
|
|
998
|
|
|
999 size_t
|
|
|
1000 class_getInstanceSize (Class class_)
|
|
|
1001 {
|
|
|
1002 if (class_ == Nil)
|
|
|
1003 return 0;
|
|
|
1004
|
|
|
1005 return class_->instance_size;
|
|
|
1006 }
|
|
|
1007
|
