1 /* src/vm/classcache.hpp - loaded class cache and loading constraints
3 Copyright (C) 1996-2005, 2006, 2007, 2008
4 CACAOVM - Verein zur Foerderung der freien virtuellen Maschine CACAO
6 This file is part of CACAO.
8 This program is free software; you can redistribute it and/or
9 modify it under the terms of the GNU General Public License as
10 published by the Free Software Foundation; either version 2, or (at
11 your option) any later version.
13 This program is distributed in the hope that it will be useful, but
14 WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16 General Public License for more details.
18 You should have received a copy of the GNU General Public License
19 along with this program; if not, write to the Free Software
20 Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
33 #include <stdio.h> /* for FILE */
35 #include "toolbox/hashtable.h"
37 #include "vm/class.hpp"
38 #include "vm/global.h"
39 #include "vm/loader.hpp"
40 #include "vm/references.h"
47 /* forward declarations *******************************************************/
49 typedef struct classcache_name_entry classcache_name_entry;
50 typedef struct classcache_class_entry classcache_class_entry;
51 typedef struct classcache_loader_entry classcache_loader_entry;
53 /* global variables ***********************************************************/
55 extern hashtable hashtable_classcache;
58 /* structs ********************************************************************/
60 /*----------------------------------------------------------------------------*/
61 /* The Loaded Class Cache */
63 /* The loaded class cache is implemented as a two-level data structure. */
65 /* The first level is a hash table indexed by class names. For each class */
66 /* name in the cache there is a classcache_name_entry, which collects all */
67 /* information about classes with this class name. */
69 /* Second level: For each classcache_name_entry there is a list of */
70 /* classcache_class_entry:s representing the possible different resolutions */
71 /* of the class name. */
73 /* A classcache_class_entry records the following: */
75 /* - the loaded class object, if this entry has been resolved, otherwise NULL */
76 /* - the list of initiating loaders which have resolved the class name to */
77 /* this class object */
78 /* - the list of initiating loaders which are constrained to resolve this */
79 /* class name to this class object in the future */
81 /* The classcache_class_entry:s approximate the equivalence classes created */
82 /* by the loading constraints and the equivalence of loaded classes. */
84 /* When a loading constraint (loaderA,loaderB,NAME) is added, then the */
85 /* classcache_class_entry:s for NAME containing loaderA and loaderB resp. */
86 /* must be merged into one entry. If this is impossible, because the entries */
87 /* have already been resolved to different class objects, then the constraint */
88 /* is violated and an expception must be thrown. */
89 /*----------------------------------------------------------------------------*/
92 /* classcache_name_entry
94 * For each classname a classcache_name_entry struct is created.
97 struct classcache_name_entry
99 utf *name; /* class name */
100 classcache_name_entry *hashlink; /* link for external chaining */
101 classcache_class_entry *classes; /* equivalence classes for this name*/
104 struct classcache_class_entry
106 classinfo *classobj; /* the loaded class object, or NULL */
107 classcache_loader_entry *loaders;
108 classcache_loader_entry *constraints;
109 classcache_class_entry *next; /* next class entry for same name */
112 struct classcache_loader_entry
114 classloader_t *loader; /* class loader object */
115 classcache_loader_entry *next; /* next loader entry in the list */
119 /* callback function type for classcache_foreach_loaded_class */
121 typedef void (*classcache_foreach_functionptr_t)(classinfo *, void *);
124 /* function prototypes ********************************************************/
126 /* initialize the loaded class cache */
127 bool classcache_init(void);
128 void classcache_free(void);
130 classinfo * classcache_lookup(classloader_t *initloader,utf *classname);
131 classinfo * classcache_lookup_defined(classloader_t *defloader,utf *classname);
132 classinfo * classcache_lookup_defined_or_initiated(classloader_t *loader,utf *classname);
134 bool classcache_store_unique(classinfo *cls);
135 classinfo * classcache_store(classloader_t *initloader,classinfo *cls,bool mayfree);
136 classinfo * classcache_store_defined(classinfo *cls);
138 #if defined(ENABLE_VERIFIER)
139 bool classcache_add_constraint(classloader_t *a,classloader_t *b,utf *classname);
140 bool classcache_add_constraints_for_params(classloader_t *a,classloader_t *b,
144 s4 classcache_get_loaded_class_count(void);
146 void classcache_foreach_loaded_class(classcache_foreach_functionptr_t func,
150 void classcache_debug_dump(FILE *file,utf *only);
157 #endif /* _CLASSCACHE_H */
160 * These are local overrides for various environment variables in Emacs.
161 * Please do not remove this and leave it at the end of the file, where
162 * Emacs will automagically detect them.
163 * ---------------------------------------------------------------------
166 * indent-tabs-mode: t
170 * vim:noexpandtab:sw=4:ts=4: