mirror of git://gcc.gnu.org/git/gcc.git
359 lines
10 KiB
C
359 lines
10 KiB
C
/* GNU Objective C Runtime class related functions
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Copyright (C) 1993, 1995, 1996, 1997 Free Software Foundation, Inc.
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Contributed by Kresten Krab Thorup and Dennis Glatting.
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This file is part of GNU CC.
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GNU CC 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 2, or (at your option) any later version.
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GNU CC 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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You should have received a copy of the GNU General Public License along with
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GNU CC; see the file COPYING. If not, write to the Free Software
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Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */
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/* As a special exception, if you link this library with files compiled with
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GCC to produce an executable, this does not cause the resulting executable
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to be covered by the GNU General Public License. This exception does not
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however invalidate any other reasons why the executable file might be
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covered by the GNU General Public License. */
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#include "runtime.h" /* the kitchen sink */
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#include "sarray.h"
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/* The table of classname->class. Used for objc_lookup_class and friends */
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static cache_ptr __objc_class_hash = 0; /* !T:MUTEX */
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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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Class (*_objc_lookup_class)(const char* name) = 0; /* !T:SAFE */
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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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/* Initial number of buckets size of class hash table. */
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#define CLASS_HASH_SIZE 32
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void __objc_init_class_tables()
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{
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/* Allocate the class hash table */
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if(__objc_class_hash)
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return;
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objc_mutex_lock(__objc_runtime_mutex);
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__objc_class_hash
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= hash_new (CLASS_HASH_SIZE,
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(hash_func_type) hash_string,
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(compare_func_type) compare_strings);
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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 */
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void
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__objc_add_class_to_hash(Class class)
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{
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Class h_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(__objc_class_hash);
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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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h_class = hash_value_for_key (__objc_class_hash, class->name);
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if (!h_class)
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{
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/* The class isn't in the hash table. Add the class and assign a class
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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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hash_add (&__objc_class_hash, class->name, class);
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}
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objc_mutex_unlock(__objc_runtime_mutex);
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}
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/* Get the class object for the class named NAME. If NAME does not
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identify a known class, the hook _objc_lookup_class is called. If
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this fails, nil is returned */
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Class objc_lookup_class (const char* name)
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{
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Class class;
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objc_mutex_lock(__objc_runtime_mutex);
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/* Make sure the class hash table exists. */
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assert (__objc_class_hash);
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class = hash_value_for_key (__objc_class_hash, name);
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objc_mutex_unlock(__objc_runtime_mutex);
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if (class)
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return class;
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if (_objc_lookup_class)
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return (*_objc_lookup_class)(name);
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else
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return 0;
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}
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/* Get the class object for the class named NAME. If NAME does not
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identify a known class, the hook _objc_lookup_class is called. If
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this fails, an error message is issued and the system aborts */
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Class
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objc_get_class (const char *name)
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{
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Class class;
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objc_mutex_lock(__objc_runtime_mutex);
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/* Make sure the class hash table exists. */
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assert (__objc_class_hash);
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class = hash_value_for_key (__objc_class_hash, name);
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objc_mutex_unlock(__objc_runtime_mutex);
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if (class)
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return class;
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if (_objc_lookup_class)
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class = (*_objc_lookup_class)(name);
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if(class)
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return class;
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objc_error(nil, OBJC_ERR_BAD_CLASS,
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"objc runtime: cannot find class %s\n", name);
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return 0;
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}
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MetaClass
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objc_get_meta_class(const char *name)
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{
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return objc_get_class(name)->class_pointer;
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}
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/* This function provides a way to enumerate all the classes in the
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executable. Pass *ENUM_STATE == NULL to start the enumeration. The
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function will return 0 when there are no more classes.
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For example:
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id class;
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void *es = NULL;
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while ((class = objc_next_class(&es)))
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... do something with class;
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*/
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Class
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objc_next_class(void **enum_state)
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{
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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(__objc_class_hash);
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*(node_ptr*)enum_state =
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hash_next(__objc_class_hash, *(node_ptr*)enum_state);
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objc_mutex_unlock(__objc_runtime_mutex);
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if (*(node_ptr*)enum_state)
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return (*(node_ptr*)enum_state)->value;
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return (Class)0;
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}
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/* Resolve super/subclass links for all classes. The only thing we
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can be sure of is that the class_pointer for class objects point
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to the right meta class objects */
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void __objc_resolve_class_links()
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{
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node_ptr node;
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Class object_class = objc_get_class ("Object");
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assert(object_class);
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objc_mutex_lock(__objc_runtime_mutex);
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/* Assign subclass links */
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for (node = hash_next (__objc_class_hash, NULL); node;
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node = hash_next (__objc_class_hash, node))
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{
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Class class1 = node->value;
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/* Make sure we have what we think we have. */
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assert (CLS_ISCLASS(class1));
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assert (CLS_ISMETA(class1->class_pointer));
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/* The class_pointer of all meta classes point to Object's meta class. */
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class1->class_pointer->class_pointer = object_class->class_pointer;
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if (!(CLS_ISRESOLV(class1)))
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{
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CLS_SETRESOLV(class1);
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CLS_SETRESOLV(class1->class_pointer);
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if(class1->super_class)
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{
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Class a_super_class
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= objc_get_class ((char *) class1->super_class);
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assert (a_super_class);
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DEBUG_PRINTF ("making class connections for: %s\n",
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class1->name);
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/* assign subclass links for superclass */
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class1->sibling_class = a_super_class->subclass_list;
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a_super_class->subclass_list = class1;
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/* Assign subclass links for meta class of superclass */
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if (a_super_class->class_pointer)
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{
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class1->class_pointer->sibling_class
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= a_super_class->class_pointer->subclass_list;
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a_super_class->class_pointer->subclass_list
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= class1->class_pointer;
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}
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}
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else /* a root class, make its meta object */
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/* be a subclass of Object */
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{
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class1->class_pointer->sibling_class
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= object_class->subclass_list;
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object_class->subclass_list = class1->class_pointer;
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}
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}
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}
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/* Assign superclass links */
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for (node = hash_next (__objc_class_hash, NULL); node;
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node = hash_next (__objc_class_hash, node))
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{
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Class class1 = node->value;
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Class sub_class;
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for (sub_class = class1->subclass_list; sub_class;
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sub_class = sub_class->sibling_class)
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{
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sub_class->super_class = class1;
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if(CLS_ISCLASS(sub_class))
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sub_class->class_pointer->super_class = class1->class_pointer;
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}
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}
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objc_mutex_unlock(__objc_runtime_mutex);
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}
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#define CLASSOF(c) ((c)->class_pointer)
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Class
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class_pose_as (Class impostor, Class super_class)
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{
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node_ptr node;
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Class class1;
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if (!CLS_ISRESOLV (impostor))
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__objc_resolve_class_links ();
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/* preconditions */
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assert (impostor);
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assert (super_class);
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assert (impostor->super_class == super_class);
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assert (CLS_ISCLASS (impostor));
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assert (CLS_ISCLASS (super_class));
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assert (impostor->instance_size == super_class->instance_size);
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{
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Class *subclass = &(super_class->subclass_list);
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/* move subclasses of super_class to impostor */
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while (*subclass)
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{
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Class nextSub = (*subclass)->sibling_class;
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if (*subclass != impostor)
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{
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Class sub = *subclass;
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/* classes */
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sub->sibling_class = impostor->subclass_list;
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sub->super_class = impostor;
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impostor->subclass_list = sub;
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/* It will happen that SUB is not a class object if it is
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the top of the meta class hierarchy chain. (root
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meta-class objects inherit their class object) If that is
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the case... don't mess with the meta-meta class. */
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if (CLS_ISCLASS (sub))
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{
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/* meta classes */
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CLASSOF (sub)->sibling_class =
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CLASSOF (impostor)->subclass_list;
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CLASSOF (sub)->super_class = CLASSOF (impostor);
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CLASSOF (impostor)->subclass_list = CLASSOF (sub);
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}
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}
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*subclass = nextSub;
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}
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/* set subclasses of superclass to be impostor only */
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super_class->subclass_list = impostor;
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CLASSOF (super_class)->subclass_list = CLASSOF (impostor);
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/* set impostor to have no sibling classes */
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impostor->sibling_class = 0;
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CLASSOF (impostor)->sibling_class = 0;
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}
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/* check relationship of impostor and super_class is kept. */
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assert (impostor->super_class == super_class);
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assert (CLASSOF (impostor)->super_class == CLASSOF (super_class));
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/* This is how to update the lookup table. Regardless of
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what the keys of the hashtable is, change all values that are
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superclass into impostor. */
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objc_mutex_lock(__objc_runtime_mutex);
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for (node = hash_next (__objc_class_hash, NULL); node;
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node = hash_next (__objc_class_hash, node))
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{
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class1 = (Class)node->value;
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if (class1 == super_class)
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{
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node->value = impostor; /* change hash table value */
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}
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}
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objc_mutex_unlock(__objc_runtime_mutex);
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/* next, we update the dispatch tables... */
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__objc_update_dispatch_table_for_class (CLASSOF (impostor));
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__objc_update_dispatch_table_for_class (impostor);
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return impostor;
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}
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