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1008 lines
28 KiB
C
1008 lines
28 KiB
C
/* GNU Objective C Runtime class related functions
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Copyright (C) 1993-2022 Free Software Foundation, Inc.
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Contributed by Kresten Krab Thorup and Dennis Glatting.
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Lock-free class table code designed and written from scratch by
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Nicola Pero, 2001.
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This file is part of GCC.
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GCC is free software; you can redistribute it and/or modify it under the
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terms of the GNU General Public License as published by the Free Software
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Foundation; either version 3, or (at your option) any later version.
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GCC is distributed in the hope that it will be useful, but WITHOUT ANY
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WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
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FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
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details.
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Under Section 7 of GPL version 3, you are granted additional
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permissions described in the GCC Runtime Library Exception, version
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3.1, as published by the Free Software Foundation.
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You should have received a copy of the GNU General Public License and
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a copy of the GCC Runtime Library Exception along with this program;
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see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
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<http://www.gnu.org/licenses/>. */
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/* The code in this file critically affects class method invocation
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speed. This long preamble comment explains why, and the issues
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involved.
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One of the traditional weaknesses of the GNU Objective-C runtime is
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that class method invocations are slow. The reason is that when you
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write
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array = [NSArray new];
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this gets basically compiled into the equivalent of
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array = [(objc_get_class ("NSArray")) new];
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objc_get_class returns the class pointer corresponding to the string
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`NSArray'; and because of the lookup, the operation is more
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complicated and slow than a simple instance method invocation.
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Most high performance Objective-C code (using the GNU Objc runtime)
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I had the opportunity to read (or write) work around this problem by
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caching the class pointer:
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Class arrayClass = [NSArray class];
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... later on ...
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array = [arrayClass new];
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array = [arrayClass new];
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array = [arrayClass new];
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In this case, you always perform a class lookup (the first one), but
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then all the [arrayClass new] methods run exactly as fast as an
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instance method invocation. It helps if you have many class method
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invocations to the same class.
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The long-term solution to this problem would be to modify the
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compiler to output tables of class pointers corresponding to all the
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class method invocations, and to add code to the runtime to update
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these tables - that should in the end allow class method invocations
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to perform precisely as fast as instance method invocations, because
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no class lookup would be involved. I think the Apple Objective-C
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runtime uses this technique. Doing this involves synchronized
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modifications in the runtime and in the compiler.
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As a first medicine to the problem, I [NP] have redesigned and
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rewritten the way the runtime is performing class lookup. This
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doesn't give as much speed as the other (definitive) approach, but
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at least a class method invocation now takes approximately 4.5 times
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an instance method invocation on my machine (it would take approx 12
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times before the rewriting), which is a lot better.
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One of the main reason the new class lookup is so faster is because
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I implemented it in a way that can safely run multithreaded without
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using locks - a so-called `lock-free' data structure. The atomic
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operation is pointer assignment. The reason why in this problem
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lock-free data structures work so well is that you never remove
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classes from the table - and the difficult thing with lock-free data
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structures is freeing data when is removed from the structures. */
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#include "objc-private/common.h"
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#include "objc-private/error.h"
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#include "objc/runtime.h"
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#include "objc/thr.h"
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#include "objc-private/module-abi-8.h" /* For CLS_ISCLASS and similar. */
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#include "objc-private/runtime.h" /* the kitchen sink */
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#include "objc-private/sarray.h" /* For sarray_put_at_safe. */
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#include "objc-private/selector.h" /* For sarray_put_at_safe. */
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#include <string.h> /* For memset */
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/* We use a table which maps a class name to the corresponding class
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pointer. The first part of this file defines this table, and
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functions to do basic operations on the table. The second part of
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the file implements some higher level Objective-C functionality for
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classes by using the functions provided in the first part to manage
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the table. */
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/**
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** Class Table Internals
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**/
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/* A node holding a class */
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typedef struct class_node
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{
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struct class_node *next; /* Pointer to next entry on the list.
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NULL indicates end of list. */
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const char *name; /* The class name string */
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int length; /* The class name string length */
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Class pointer; /* The Class pointer */
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} *class_node_ptr;
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/* A table containing classes is a class_node_ptr (pointing to the
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first entry in the table - if it is NULL, then the table is
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empty). */
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/* We have 1024 tables. Each table contains all class names which
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have the same hash (which is a number between 0 and 1023). To look
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up a class_name, we compute its hash, and get the corresponding
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table. Once we have the table, we simply compare strings directly
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till we find the one which we want (using the length first). The
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number of tables is quite big on purpose (a normal big application
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has less than 1000 classes), so that you shouldn't normally get any
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collisions, and get away with a single comparison (which we can't
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avoid since we need to know that you have got the right thing). */
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#define CLASS_TABLE_SIZE 1024
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#define CLASS_TABLE_MASK 1023
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static class_node_ptr class_table_array[CLASS_TABLE_SIZE];
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/* The table writing mutex - we lock on writing to avoid conflicts
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between different writers, but we read without locks. That is
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possible because we assume pointer assignment to be an atomic
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operation. TODO: This is only true under certain circumstances,
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which should be clarified. */
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static objc_mutex_t __class_table_lock = NULL;
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/* CLASS_TABLE_HASH is how we compute the hash of a class name. It is
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a macro - *not* a function - arguments *are* modified directly.
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INDEX should be a variable holding an int;
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HASH should be a variable holding an int;
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CLASS_NAME should be a variable holding a (char *) to the class_name.
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After the macro is executed, INDEX contains the length of the
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string, and HASH the computed hash of the string; CLASS_NAME is
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untouched. */
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#define CLASS_TABLE_HASH(INDEX, HASH, CLASS_NAME) \
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do { \
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HASH = 0; \
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for (INDEX = 0; CLASS_NAME[INDEX] != '\0'; INDEX++) \
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{ \
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HASH = (HASH << 4) ^ (HASH >> 28) ^ CLASS_NAME[INDEX]; \
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} \
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\
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HASH = (HASH ^ (HASH >> 10) ^ (HASH >> 20)) & CLASS_TABLE_MASK; \
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} while (0)
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/* Setup the table. */
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static void
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class_table_setup (void)
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{
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/* Start - nothing in the table. */
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memset (class_table_array, 0, sizeof (class_node_ptr) * CLASS_TABLE_SIZE);
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/* The table writing mutex. */
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__class_table_lock = objc_mutex_allocate ();
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}
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/* Insert a class in the table (used when a new class is
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registered). */
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static void
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class_table_insert (const char *class_name, Class class_pointer)
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{
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int hash, length;
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class_node_ptr new_node;
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/* Find out the class name's hash and length. */
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CLASS_TABLE_HASH (length, hash, class_name);
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/* Prepare the new node holding the class. */
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new_node = objc_malloc (sizeof (struct class_node));
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new_node->name = class_name;
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new_node->length = length;
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new_node->pointer = class_pointer;
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/* Lock the table for modifications. */
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objc_mutex_lock (__class_table_lock);
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/* Insert the new node in the table at the beginning of the table at
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class_table_array[hash]. */
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new_node->next = class_table_array[hash];
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class_table_array[hash] = new_node;
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objc_mutex_unlock (__class_table_lock);
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}
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/* Get a class from the table. This does not need mutex protection.
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Currently, this function is called each time you call a static
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method, this is why it must be very fast. */
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static inline Class
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class_table_get_safe (const char *class_name)
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{
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class_node_ptr node;
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int length, hash;
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/* Compute length and hash. */
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CLASS_TABLE_HASH (length, hash, class_name);
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node = class_table_array[hash];
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if (node != NULL)
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{
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do
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{
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if (node->length == length)
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{
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/* Compare the class names. */
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int i;
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for (i = 0; i < length; i++)
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{
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if ((node->name)[i] != class_name[i])
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break;
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}
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if (i == length)
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{
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/* They are equal! */
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return node->pointer;
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}
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}
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}
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while ((node = node->next) != NULL);
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}
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return Nil;
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}
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/* Enumerate over the class table. */
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struct class_table_enumerator
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{
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int hash;
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class_node_ptr node;
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};
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static Class
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class_table_next (struct class_table_enumerator **e)
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{
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struct class_table_enumerator *enumerator = *e;
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class_node_ptr next;
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if (enumerator == NULL)
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{
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*e = objc_malloc (sizeof (struct class_table_enumerator));
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enumerator = *e;
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enumerator->hash = 0;
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enumerator->node = NULL;
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next = class_table_array[enumerator->hash];
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}
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else
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next = enumerator->node->next;
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if (next != NULL)
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{
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enumerator->node = next;
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return enumerator->node->pointer;
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}
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else
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{
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enumerator->hash++;
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while (enumerator->hash < CLASS_TABLE_SIZE)
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{
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next = class_table_array[enumerator->hash];
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if (next != NULL)
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{
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enumerator->node = next;
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return enumerator->node->pointer;
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}
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enumerator->hash++;
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}
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/* Ok - table finished - done. */
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objc_free (enumerator);
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return Nil;
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}
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}
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#if 0 /* DEBUGGING FUNCTIONS */
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/* Debugging function - print the class table. */
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void
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class_table_print (void)
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{
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int i;
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for (i = 0; i < CLASS_TABLE_SIZE; i++)
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{
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class_node_ptr node;
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printf ("%d:\n", i);
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node = class_table_array[i];
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while (node != NULL)
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{
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printf ("\t%s\n", node->name);
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node = node->next;
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}
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}
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}
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/* Debugging function - print an histogram of number of classes in
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function of hash key values. Useful to evaluate the hash function
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in real cases. */
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void
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class_table_print_histogram (void)
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{
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int i, j;
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int counter = 0;
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for (i = 0; i < CLASS_TABLE_SIZE; i++)
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{
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class_node_ptr node;
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node = class_table_array[i];
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while (node != NULL)
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{
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counter++;
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node = node->next;
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}
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if (((i + 1) % 50) == 0)
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{
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printf ("%4d:", i + 1);
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for (j = 0; j < counter; j++)
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printf ("X");
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printf ("\n");
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counter = 0;
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}
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}
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printf ("%4d:", i + 1);
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for (j = 0; j < counter; j++)
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printf ("X");
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printf ("\n");
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}
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#endif /* DEBUGGING FUNCTIONS */
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/**
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** Objective-C runtime functions
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**/
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/* From now on, the only access to the class table data structure
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should be via the class_table_* functions. */
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/* This is a hook which is called by objc_get_class and
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objc_lookup_class if the runtime is not able to find the class.
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This may e.g. try to load in the class using dynamic loading.
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This hook was a public, global variable in the Traditional GNU
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Objective-C Runtime API (objc/objc-api.h). The modern GNU
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Objective-C Runtime API (objc/runtime.h) provides the
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objc_setGetUnknownClassHandler() function instead.
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*/
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Class (*_objc_lookup_class) (const char *name) = 0; /* !T:SAFE */
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/* The handler currently in use. PS: if both
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__obj_get_unknown_class_handler and _objc_lookup_class are defined,
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__objc_get_unknown_class_handler is called first. */
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static objc_get_unknown_class_handler
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__objc_get_unknown_class_handler = NULL;
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objc_get_unknown_class_handler
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objc_setGetUnknownClassHandler (objc_get_unknown_class_handler
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new_handler)
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{
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objc_get_unknown_class_handler old_handler
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= __objc_get_unknown_class_handler;
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__objc_get_unknown_class_handler = new_handler;
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return old_handler;
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}
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/* True when class links has been resolved. */
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BOOL __objc_class_links_resolved = NO; /* !T:UNUSED */
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void
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__objc_init_class_tables (void)
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{
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/* Allocate the class hash table. */
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if (__class_table_lock)
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return;
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objc_mutex_lock (__objc_runtime_mutex);
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class_table_setup ();
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objc_mutex_unlock (__objc_runtime_mutex);
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}
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/* This function adds a class to the class hash table, and assigns the
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class a number, unless it's already known. Return 'YES' if the
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class was added. Return 'NO' if the class was already known. */
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BOOL
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__objc_add_class_to_hash (Class class)
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{
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Class existing_class;
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objc_mutex_lock (__objc_runtime_mutex);
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/* Make sure the table is there. */
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assert (__class_table_lock);
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/* Make sure it's not a meta class. */
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assert (CLS_ISCLASS (class));
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/* Check to see if the class is already in the hash table. */
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existing_class = class_table_get_safe (class->name);
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if (existing_class)
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{
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objc_mutex_unlock (__objc_runtime_mutex);
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return NO;
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}
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else
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{
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/* The class isn't in the hash table. Add the class and assign
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a class number. */
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static unsigned int class_number = 1;
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CLS_SETNUMBER (class, class_number);
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CLS_SETNUMBER (class->class_pointer, class_number);
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++class_number;
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class_table_insert (class->name, class);
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objc_mutex_unlock (__objc_runtime_mutex);
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return YES;
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}
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}
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Class
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objc_getClass (const char *name)
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{
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Class class;
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if (name == NULL)
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return Nil;
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class = class_table_get_safe (name);
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if (class)
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return class;
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if (__objc_get_unknown_class_handler)
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return (*__objc_get_unknown_class_handler) (name);
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if (_objc_lookup_class)
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return (*_objc_lookup_class) (name);
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return Nil;
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}
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Class
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objc_lookUpClass (const char *name)
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{
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if (name == NULL)
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return Nil;
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else
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return class_table_get_safe (name);
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}
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Class
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objc_getMetaClass (const char *name)
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{
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Class class = objc_getClass (name);
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if (class)
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return class->class_pointer;
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else
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return Nil;
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}
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Class
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objc_getRequiredClass (const char *name)
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{
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Class class = objc_getClass (name);
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if (class)
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return class;
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else
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_objc_abort ("objc_getRequiredClass ('%s') failed: class not found\n", name);
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}
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int
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objc_getClassList (Class *returnValue, int maxNumberOfClassesToReturn)
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{
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/* Iterate over all entries in the table. */
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int hash, count = 0;
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for (hash = 0; hash < CLASS_TABLE_SIZE; hash++)
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{
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class_node_ptr node = class_table_array[hash];
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while (node != NULL)
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{
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if (returnValue)
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{
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if (count < maxNumberOfClassesToReturn)
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returnValue[count] = node->pointer;
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else
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return count;
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}
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count++;
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node = node->next;
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}
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}
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return count;
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}
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Class
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objc_allocateClassPair (Class super_class, const char *class_name, size_t extraBytes)
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{
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Class new_class;
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Class new_meta_class;
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if (class_name == NULL)
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return Nil;
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if (objc_getClass (class_name))
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return Nil;
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if (super_class)
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{
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/* If you want to build a hierarchy of classes, you need to
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build and register them one at a time. The risk is that you
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are able to cause confusion by registering a subclass before
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the superclass or similar. */
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if (CLS_IS_IN_CONSTRUCTION (super_class))
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return Nil;
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}
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/* Technically, we should create the metaclass first, then use
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class_createInstance() to create the class. That complication
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would be relevant if we had class variables, but we don't, so we
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just ignore it and create everything directly and assume all
|
|
classes have the same size. */
|
|
new_class = objc_calloc (1, sizeof (struct objc_class) + extraBytes);
|
|
new_meta_class = objc_calloc (1, sizeof (struct objc_class) + extraBytes);
|
|
|
|
/* We create an unresolved class, similar to one generated by the
|
|
compiler. It will be resolved later when we register it.
|
|
|
|
Note how the metaclass details are not that important; when the
|
|
class is resolved, the ones that matter will be fixed up. */
|
|
new_class->class_pointer = new_meta_class;
|
|
new_meta_class->class_pointer = 0;
|
|
|
|
if (super_class)
|
|
{
|
|
/* Force the name of the superclass in place of the link to the
|
|
actual superclass, which will be put there when the class is
|
|
resolved. */
|
|
const char *super_class_name = class_getName (super_class);
|
|
new_class->super_class = (void *)super_class_name;
|
|
new_meta_class->super_class = (void *)super_class_name;
|
|
}
|
|
else
|
|
{
|
|
new_class->super_class = (void *)0;
|
|
new_meta_class->super_class = (void *)0;
|
|
}
|
|
|
|
new_class->name = objc_malloc (strlen (class_name) + 1);
|
|
strcpy ((char*)new_class->name, class_name);
|
|
new_meta_class->name = new_class->name;
|
|
|
|
new_class->version = 0;
|
|
new_meta_class->version = 0;
|
|
|
|
new_class->info = _CLS_CLASS | _CLS_IN_CONSTRUCTION;
|
|
new_meta_class->info = _CLS_META | _CLS_IN_CONSTRUCTION;
|
|
|
|
if (super_class)
|
|
new_class->instance_size = super_class->instance_size;
|
|
else
|
|
new_class->instance_size = 0;
|
|
new_meta_class->instance_size = sizeof (struct objc_class);
|
|
|
|
return new_class;
|
|
}
|
|
|
|
void
|
|
objc_registerClassPair (Class class_)
|
|
{
|
|
if (class_ == Nil)
|
|
return;
|
|
|
|
if ((! CLS_ISCLASS (class_)) || (! CLS_IS_IN_CONSTRUCTION (class_)))
|
|
return;
|
|
|
|
if ((! CLS_ISMETA (class_->class_pointer)) || (! CLS_IS_IN_CONSTRUCTION (class_->class_pointer)))
|
|
return;
|
|
|
|
objc_mutex_lock (__objc_runtime_mutex);
|
|
|
|
if (objc_getClass (class_->name))
|
|
{
|
|
objc_mutex_unlock (__objc_runtime_mutex);
|
|
return;
|
|
}
|
|
|
|
CLS_SET_NOT_IN_CONSTRUCTION (class_);
|
|
CLS_SET_NOT_IN_CONSTRUCTION (class_->class_pointer);
|
|
|
|
__objc_init_class (class_);
|
|
|
|
/* Resolve class links immediately. No point in waiting. */
|
|
__objc_resolve_class_links ();
|
|
|
|
objc_mutex_unlock (__objc_runtime_mutex);
|
|
}
|
|
|
|
void
|
|
objc_disposeClassPair (Class class_)
|
|
{
|
|
if (class_ == Nil)
|
|
return;
|
|
|
|
if ((! CLS_ISCLASS (class_)) || (! CLS_IS_IN_CONSTRUCTION (class_)))
|
|
return;
|
|
|
|
if ((! CLS_ISMETA (class_->class_pointer)) || (! CLS_IS_IN_CONSTRUCTION (class_->class_pointer)))
|
|
return;
|
|
|
|
/* Undo any class_addIvar(). */
|
|
if (class_->ivars)
|
|
{
|
|
int i;
|
|
for (i = 0; i < class_->ivars->ivar_count; i++)
|
|
{
|
|
struct objc_ivar *ivar = &(class_->ivars->ivar_list[i]);
|
|
|
|
objc_free ((char *)ivar->ivar_name);
|
|
objc_free ((char *)ivar->ivar_type);
|
|
}
|
|
|
|
objc_free (class_->ivars);
|
|
}
|
|
|
|
/* Undo any class_addMethod(). */
|
|
if (class_->methods)
|
|
{
|
|
struct objc_method_list *list = class_->methods;
|
|
while (list)
|
|
{
|
|
int i;
|
|
struct objc_method_list *next = list->method_next;
|
|
|
|
for (i = 0; i < list->method_count; i++)
|
|
{
|
|
struct objc_method *method = &(list->method_list[i]);
|
|
|
|
objc_free ((char *)method->method_name);
|
|
objc_free ((char *)method->method_types);
|
|
}
|
|
|
|
objc_free (list);
|
|
list = next;
|
|
}
|
|
}
|
|
|
|
/* Undo any class_addProtocol(). */
|
|
if (class_->protocols)
|
|
{
|
|
struct objc_protocol_list *list = class_->protocols;
|
|
while (list)
|
|
{
|
|
struct objc_protocol_list *next = list->next;
|
|
|
|
objc_free (list);
|
|
list = next;
|
|
}
|
|
}
|
|
|
|
/* Undo any class_addMethod() on the meta-class. */
|
|
if (class_->class_pointer->methods)
|
|
{
|
|
struct objc_method_list *list = class_->class_pointer->methods;
|
|
while (list)
|
|
{
|
|
int i;
|
|
struct objc_method_list *next = list->method_next;
|
|
|
|
for (i = 0; i < list->method_count; i++)
|
|
{
|
|
struct objc_method *method = &(list->method_list[i]);
|
|
|
|
objc_free ((char *)method->method_name);
|
|
objc_free ((char *)method->method_types);
|
|
}
|
|
|
|
objc_free (list);
|
|
list = next;
|
|
}
|
|
}
|
|
|
|
/* Undo objc_allocateClassPair(). */
|
|
objc_free ((char *)(class_->name));
|
|
objc_free (class_->class_pointer);
|
|
objc_free (class_);
|
|
}
|
|
|
|
/* Traditional GNU Objective-C Runtime API. Important: this method is
|
|
called automatically by the compiler while messaging (if using the
|
|
traditional ABI), so it is worth keeping it fast; don't make it
|
|
just a wrapper around objc_getClass(). */
|
|
/* Note that this is roughly equivalent to objc_getRequiredClass(). */
|
|
/* Get the class object for the class named NAME. If NAME does not
|
|
identify a known class, the hook _objc_lookup_class is called. If
|
|
this fails, an error message is issued and the system aborts. */
|
|
Class
|
|
objc_get_class (const char *name)
|
|
{
|
|
Class class;
|
|
|
|
class = class_table_get_safe (name);
|
|
|
|
if (class)
|
|
return class;
|
|
|
|
if (__objc_get_unknown_class_handler)
|
|
class = (*__objc_get_unknown_class_handler) (name);
|
|
|
|
if ((!class) && _objc_lookup_class)
|
|
class = (*_objc_lookup_class) (name);
|
|
|
|
if (class)
|
|
return class;
|
|
|
|
_objc_abort ("objc runtime: cannot find class %s\n", name);
|
|
|
|
return 0;
|
|
}
|
|
|
|
/* This is used by the compiler too. */
|
|
Class
|
|
objc_get_meta_class (const char *name)
|
|
{
|
|
return objc_get_class (name)->class_pointer;
|
|
}
|
|
|
|
/* This is not used by GCC, but the clang compiler seems to use it
|
|
when targeting the GNU runtime. That's wrong, but we have it to
|
|
be compatible. */
|
|
Class
|
|
objc_lookup_class (const char *name)
|
|
{
|
|
return objc_getClass (name);
|
|
}
|
|
|
|
/* This is used when the implementation of a method changes. It goes
|
|
through all classes, looking for the ones that have these methods
|
|
(either method_a or method_b; method_b can be NULL), and reloads
|
|
the implementation for these. You should call this with the
|
|
runtime mutex already locked. */
|
|
void
|
|
__objc_update_classes_with_methods (struct objc_method *method_a, struct objc_method *method_b)
|
|
{
|
|
int hash;
|
|
|
|
/* Iterate over all classes. */
|
|
for (hash = 0; hash < CLASS_TABLE_SIZE; hash++)
|
|
{
|
|
class_node_ptr node = class_table_array[hash];
|
|
|
|
while (node != NULL)
|
|
{
|
|
/* We execute this loop twice: the first time, we iterate
|
|
over all methods in the class (instance methods), while
|
|
the second time we iterate over all methods in the meta
|
|
class (class methods). */
|
|
Class class = Nil;
|
|
BOOL done = NO;
|
|
|
|
while (done == NO)
|
|
{
|
|
struct objc_method_list * method_list;
|
|
|
|
if (class == Nil)
|
|
{
|
|
/* The first time, we work on the class. */
|
|
class = node->pointer;
|
|
}
|
|
else
|
|
{
|
|
/* The second time, we work on the meta class. */
|
|
class = class->class_pointer;
|
|
done = YES;
|
|
}
|
|
|
|
method_list = class->methods;
|
|
|
|
while (method_list)
|
|
{
|
|
int i;
|
|
|
|
for (i = 0; i < method_list->method_count; ++i)
|
|
{
|
|
struct objc_method *method = &method_list->method_list[i];
|
|
|
|
/* If the method is one of the ones we are
|
|
looking for, update the implementation. */
|
|
if (method == method_a)
|
|
sarray_at_put_safe (class->dtable,
|
|
(sidx) method_a->method_name->sel_id,
|
|
method_a->method_imp);
|
|
|
|
if (method == method_b)
|
|
{
|
|
if (method_b != NULL)
|
|
sarray_at_put_safe (class->dtable,
|
|
(sidx) method_b->method_name->sel_id,
|
|
method_b->method_imp);
|
|
}
|
|
}
|
|
|
|
method_list = method_list->method_next;
|
|
}
|
|
}
|
|
node = node->next;
|
|
}
|
|
}
|
|
}
|
|
|
|
/* Resolve super/subclass links for all classes. The only thing we
|
|
can be sure of is that the class_pointer for class objects point to
|
|
the right meta class objects. */
|
|
void
|
|
__objc_resolve_class_links (void)
|
|
{
|
|
struct class_table_enumerator *es = NULL;
|
|
Class object_class = objc_get_class ("Object");
|
|
Class class1;
|
|
|
|
assert (object_class);
|
|
|
|
objc_mutex_lock (__objc_runtime_mutex);
|
|
|
|
/* Assign subclass links. */
|
|
while ((class1 = class_table_next (&es)))
|
|
{
|
|
/* Make sure we have what we think we have. */
|
|
assert (CLS_ISCLASS (class1));
|
|
assert (CLS_ISMETA (class1->class_pointer));
|
|
|
|
/* The class_pointer of all meta classes point to Object's meta
|
|
class. */
|
|
class1->class_pointer->class_pointer = object_class->class_pointer;
|
|
|
|
if (! CLS_ISRESOLV (class1))
|
|
{
|
|
CLS_SETRESOLV (class1);
|
|
CLS_SETRESOLV (class1->class_pointer);
|
|
|
|
if (class1->super_class)
|
|
{
|
|
Class a_super_class
|
|
= objc_get_class ((char *) class1->super_class);
|
|
|
|
assert (a_super_class);
|
|
|
|
DEBUG_PRINTF ("making class connections for: %s\n",
|
|
class1->name);
|
|
|
|
/* Assign subclass links for superclass. */
|
|
class1->sibling_class = a_super_class->subclass_list;
|
|
a_super_class->subclass_list = class1;
|
|
|
|
/* Assign subclass links for meta class of superclass. */
|
|
if (a_super_class->class_pointer)
|
|
{
|
|
class1->class_pointer->sibling_class
|
|
= a_super_class->class_pointer->subclass_list;
|
|
a_super_class->class_pointer->subclass_list
|
|
= class1->class_pointer;
|
|
}
|
|
}
|
|
else /* A root class, make its meta object be a subclass of
|
|
Object. */
|
|
{
|
|
class1->class_pointer->sibling_class
|
|
= object_class->subclass_list;
|
|
object_class->subclass_list = class1->class_pointer;
|
|
}
|
|
}
|
|
}
|
|
|
|
/* Assign superclass links. */
|
|
es = NULL;
|
|
while ((class1 = class_table_next (&es)))
|
|
{
|
|
Class sub_class;
|
|
for (sub_class = class1->subclass_list; sub_class;
|
|
sub_class = sub_class->sibling_class)
|
|
{
|
|
sub_class->super_class = class1;
|
|
if (CLS_ISCLASS (sub_class))
|
|
sub_class->class_pointer->super_class = class1->class_pointer;
|
|
}
|
|
}
|
|
|
|
objc_mutex_unlock (__objc_runtime_mutex);
|
|
}
|
|
|
|
const char *
|
|
class_getName (Class class_)
|
|
{
|
|
if (class_ == Nil)
|
|
return "nil";
|
|
|
|
return class_->name;
|
|
}
|
|
|
|
BOOL
|
|
class_isMetaClass (Class class_)
|
|
{
|
|
/* CLS_ISMETA includes the check for Nil class_. */
|
|
return CLS_ISMETA (class_);
|
|
}
|
|
|
|
/* Even inside libobjc it may be worth using class_getSuperclass
|
|
instead of accessing class_->super_class directly because it
|
|
resolves the class links if needed. If you access
|
|
class_->super_class directly, make sure to deal with the situation
|
|
where the class is not resolved yet! */
|
|
Class
|
|
class_getSuperclass (Class class_)
|
|
{
|
|
if (class_ == Nil)
|
|
return Nil;
|
|
|
|
/* Classes that are in construction are not resolved, and still have
|
|
the class name (instead of a class pointer) in the
|
|
class_->super_class field. In that case we need to lookup the
|
|
superclass name to return the superclass. We cannot resolve the
|
|
class until it is registered. */
|
|
if (CLS_IS_IN_CONSTRUCTION (class_))
|
|
{
|
|
if (CLS_ISMETA (class_))
|
|
return object_getClass ((id)objc_lookUpClass ((const char *)(class_->super_class)));
|
|
else
|
|
return objc_lookUpClass ((const char *)(class_->super_class));
|
|
}
|
|
|
|
/* If the class is not resolved yet, super_class would point to a
|
|
string (the name of the super class) as opposed to the actual
|
|
super class. In that case, we need to resolve the class links
|
|
before we can return super_class. */
|
|
if (! CLS_ISRESOLV (class_))
|
|
__objc_resolve_class_links ();
|
|
|
|
return class_->super_class;
|
|
}
|
|
|
|
int
|
|
class_getVersion (Class class_)
|
|
{
|
|
if (class_ == Nil)
|
|
return 0;
|
|
|
|
return (int)(class_->version);
|
|
}
|
|
|
|
void
|
|
class_setVersion (Class class_, int version)
|
|
{
|
|
if (class_ == Nil)
|
|
return;
|
|
|
|
class_->version = version;
|
|
}
|
|
|
|
size_t
|
|
class_getInstanceSize (Class class_)
|
|
{
|
|
if (class_ == Nil)
|
|
return 0;
|
|
|
|
return class_->instance_size;
|
|
}
|
|
|