1998-09-21 Ben Elliston <bje@cygnus.com>

        * New directory.  Moved files from ../gcc/objc.

From-SVN: r22514

1 files changed, 358 insertions, 0 deletions

diff --git a/libobjc/class.c b/libobjc/class.c
new file mode 100644
index 00000000000..44aa1b9f98e
--- /dev/null
+++ b/libobjc/class.c
@@ -0,0 +1,358 @@
+/* GNU Objective C Runtime class related functions
+   Copyright (C) 1993, 1995, 1996, 1997 Free Software Foundation, Inc.
+   Contributed by Kresten Krab Thorup and Dennis Glatting.
+
+This file is part of GNU CC.
+
+GNU CC is free software; you can redistribute it and/or modify it under the
+terms of the GNU General Public License as published by the Free Software
+Foundation; either version 2, or (at your option) any later version.
+
+GNU CC is distributed in the hope that it will be useful, but WITHOUT ANY
+WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more
+details.
+
+You should have received a copy of the GNU General Public License along with
+GNU CC; see the file COPYING.  If not, write to the Free Software
+Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */
+
+/* As a special exception, if you link this library with files compiled with
+   GCC to produce an executable, this does not cause the resulting executable
+   to be covered by the GNU General Public License. This exception does not
+   however invalidate any other reasons why the executable file might be
+   covered by the GNU General Public License.  */
+
+#include "runtime.h"		/* the kitchen sink */
+#include "sarray.h"
+
+/* The table of classname->class.  Used for objc_lookup_class and friends */
+static cache_ptr __objc_class_hash = 0;                 /* !T:MUTEX */
+
+/* This is a hook which is called by objc_get_class and 
+   objc_lookup_class if the runtime is not able to find the class.
+   This may e.g. try to load in the class using dynamic loading */
+Class (*_objc_lookup_class)(const char* name) = 0;      /* !T:SAFE */
+
+
+/* True when class links has been resolved */     
+BOOL __objc_class_links_resolved = NO;                  /* !T:UNUSED */
+
+
+/* Initial number of buckets size of class hash table. */
+#define CLASS_HASH_SIZE 32
+
+void __objc_init_class_tables()
+{
+  /* Allocate the class hash table */
+
+  if(__objc_class_hash)
+    return;
+
+  objc_mutex_lock(__objc_runtime_mutex);
+
+  __objc_class_hash
+    =  hash_new (CLASS_HASH_SIZE,
+		 (hash_func_type) hash_string,
+		 (compare_func_type) compare_strings);
+
+  objc_mutex_unlock(__objc_runtime_mutex);
+}  
+
+/* This function adds a class to the class hash table, and assigns the 
+   class a number, unless it's already known */
+void
+__objc_add_class_to_hash(Class class)
+{
+  Class h_class;
+
+  objc_mutex_lock(__objc_runtime_mutex);
+
+  /* make sure the table is there */
+  assert(__objc_class_hash);
+
+  /* make sure it's not a meta class */  
+  assert(CLS_ISCLASS(class));
+
+  /* Check to see if the class is already in the hash table.  */
+  h_class = hash_value_for_key (__objc_class_hash, class->name);
+  if (!h_class)
+    {
+      /* The class isn't in the hash table.  Add the class and assign a class
+         number.  */
+      static unsigned int class_number = 1;
+
+      CLS_SETNUMBER(class, class_number);
+      CLS_SETNUMBER(class->class_pointer, class_number);
+
+      ++class_number;
+      hash_add (&__objc_class_hash, class->name, class);
+    }
+
+  objc_mutex_unlock(__objc_runtime_mutex);
+}
+
+/* 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, nil is returned */
+Class objc_lookup_class (const char* name)
+{
+  Class class;
+
+  objc_mutex_lock(__objc_runtime_mutex);
+
+  /* Make sure the class hash table exists.  */
+  assert (__objc_class_hash);
+
+  class = hash_value_for_key (__objc_class_hash, name);
+
+  objc_mutex_unlock(__objc_runtime_mutex);
+
+  if (class)
+    return class;
+
+  if (_objc_lookup_class)
+    return (*_objc_lookup_class)(name);
+  else
+    return 0;
+}
+
+/* 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;
+
+  objc_mutex_lock(__objc_runtime_mutex);
+
+  /* Make sure the class hash table exists.  */
+  assert (__objc_class_hash);
+
+  class = hash_value_for_key (__objc_class_hash, name);
+
+  objc_mutex_unlock(__objc_runtime_mutex);
+
+  if (class)
+    return class;
+
+  if (_objc_lookup_class)
+    class = (*_objc_lookup_class)(name);
+
+  if(class)
+    return class;
+  
+  objc_error(nil, OBJC_ERR_BAD_CLASS, 
+	     "objc runtime: cannot find class %s\n", name);
+  return 0;
+}
+
+MetaClass
+objc_get_meta_class(const char *name)
+{
+  return objc_get_class(name)->class_pointer;
+}
+
+/* This function provides a way to enumerate all the classes in the
+   executable.  Pass *ENUM_STATE == NULL to start the enumeration.  The
+   function will return 0 when there are no more classes.  
+   For example: 
+       id class; 
+       void *es = NULL;
+       while ((class = objc_next_class(&es)))
+         ... do something with class; 
+*/
+Class
+objc_next_class(void **enum_state)
+{
+  objc_mutex_lock(__objc_runtime_mutex);
+
+  /* make sure the table is there */
+  assert(__objc_class_hash);
+
+  *(node_ptr*)enum_state = 
+    hash_next(__objc_class_hash, *(node_ptr*)enum_state);
+
+  objc_mutex_unlock(__objc_runtime_mutex);
+
+  if (*(node_ptr*)enum_state)
+    return (*(node_ptr*)enum_state)->value;
+  return (Class)0;
+}
+
+/* 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()
+{
+  node_ptr node;
+  Class object_class = objc_get_class ("Object");
+
+  assert(object_class);
+
+  objc_mutex_lock(__objc_runtime_mutex);
+
+  /* Assign subclass links */
+  for (node = hash_next (__objc_class_hash, NULL); node;
+       node = hash_next (__objc_class_hash, node))
+    {
+      Class class1 = node->value;
+
+      /* 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 */
+  for (node = hash_next (__objc_class_hash, NULL); node;
+       node = hash_next (__objc_class_hash, node))
+    {
+      Class class1 = node->value;
+      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);
+}
+
+
+
+#define CLASSOF(c) ((c)->class_pointer)
+
+Class
+class_pose_as (Class impostor, Class super_class)
+{
+  node_ptr node;
+  Class class1;
+
+  if (!CLS_ISRESOLV (impostor))
+    __objc_resolve_class_links ();
+
+  /* preconditions */
+  assert (impostor);
+  assert (super_class);
+  assert (impostor->super_class == super_class);
+  assert (CLS_ISCLASS (impostor));
+  assert (CLS_ISCLASS (super_class));
+  assert (impostor->instance_size == super_class->instance_size);
+
+  {
+    Class *subclass = &(super_class->subclass_list);
+
+    /* move subclasses of super_class to impostor */
+    while (*subclass)
+      {
+	Class nextSub = (*subclass)->sibling_class;
+
+	if (*subclass != impostor)
+	  {
+	    Class sub = *subclass;
+
+	    /* classes */
+	    sub->sibling_class = impostor->subclass_list;
+	    sub->super_class = impostor;
+	    impostor->subclass_list = sub;
+
+	    /* It will happen that SUB is not a class object if it is 
+	       the top of the meta class hierarchy chain.  (root
+	       meta-class objects inherit their class object)  If that is
+	       the case... don't mess with the meta-meta class. */ 
+	    if (CLS_ISCLASS (sub))
+	      {
+		/* meta classes */
+		CLASSOF (sub)->sibling_class = 
+		  CLASSOF (impostor)->subclass_list;
+		CLASSOF (sub)->super_class = CLASSOF (impostor);
+		CLASSOF (impostor)->subclass_list = CLASSOF (sub);
+	      }
+	  }
+
+	*subclass = nextSub;
+      }
+
+    /* set subclasses of superclass to be impostor only */
+    super_class->subclass_list = impostor;
+    CLASSOF (super_class)->subclass_list = CLASSOF (impostor);
+    
+    /* set impostor to have no sibling classes */
+    impostor->sibling_class = 0;
+    CLASSOF (impostor)->sibling_class = 0;
+  }
+  
+  /* check relationship of impostor and super_class is kept. */
+  assert (impostor->super_class == super_class);
+  assert (CLASSOF (impostor)->super_class == CLASSOF (super_class));
+
+  /* This is how to update the lookup table. Regardless of
+     what the keys of the hashtable is, change all values that are
+     superclass into impostor. */
+
+  objc_mutex_lock(__objc_runtime_mutex);
+
+  for (node = hash_next (__objc_class_hash, NULL); node;
+       node = hash_next (__objc_class_hash, node))
+    {
+      class1 = (Class)node->value;
+      if (class1 == super_class)
+	{
+	  node->value = impostor; /* change hash table value */
+	}
+    }      
+
+  objc_mutex_unlock(__objc_runtime_mutex);
+
+  /* next, we update the dispatch tables... */
+  __objc_update_dispatch_table_for_class (CLASSOF (impostor));
+  __objc_update_dispatch_table_for_class (impostor);
+
+  return impostor;
+}
+  
+