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comparison src/share/vm/memory/iterator.hpp @ 0:a61af66fc99e jdk7-b24

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author duke
date Sat, 01 Dec 2007 00:00:00 +0000
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1 /*
2 * Copyright 1997-2006 Sun Microsystems, Inc. All Rights Reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
20 * CA 95054 USA or visit www.sun.com if you need additional information or
21 * have any questions.
22 *
23 */
24
25 // The following classes are C++ `closures` for iterating over objects, roots and spaces
26
27 class ReferenceProcessor;
28
29 // OopClosure is used for iterating through roots (oop*)
30
31 class OopClosure : public StackObj {
32 public:
33 ReferenceProcessor* _ref_processor;
34 OopClosure(ReferenceProcessor* rp) : _ref_processor(rp) { }
35 OopClosure() : _ref_processor(NULL) { }
36 virtual void do_oop(oop* o) = 0;
37 virtual void do_oop_v(oop* o) { do_oop(o); }
38
39 // In support of post-processing of weak links of KlassKlass objects;
40 // see KlassKlass::oop_oop_iterate().
41 virtual const bool should_remember_klasses() const { return false; }
42 virtual void remember_klass(Klass* k) { /* do nothing */ }
43
44 // If "true", invoke on nmethods (when scanning compiled frames).
45 virtual const bool do_nmethods() const { return false; }
46
47 // The methods below control how object iterations invoking this closure
48 // should be performed:
49
50 // If "true", invoke on header klass field.
51 bool do_header() { return true; } // Note that this is non-virtual.
52 // Controls how prefetching is done for invocations of this closure.
53 Prefetch::style prefetch_style() { // Note that this is non-virtual.
54 return Prefetch::do_none;
55 }
56 };
57
58 // ObjectClosure is used for iterating through an object space
59
60 class ObjectClosure : public StackObj {
61 public:
62 // Called for each object.
63 virtual void do_object(oop obj) = 0;
64 };
65
66
67 class BoolObjectClosure : public ObjectClosure {
68 public:
69 virtual bool do_object_b(oop obj) = 0;
70 };
71
72 // Applies an oop closure to all ref fields in objects iterated over in an
73 // object iteration.
74 class ObjectToOopClosure: public ObjectClosure {
75 OopClosure* _cl;
76 public:
77 void do_object(oop obj);
78 ObjectToOopClosure(OopClosure* cl) : _cl(cl) {}
79 };
80
81 // A version of ObjectClosure with "memory" (see _previous_address below)
82 class UpwardsObjectClosure: public BoolObjectClosure {
83 HeapWord* _previous_address;
84 public:
85 UpwardsObjectClosure() : _previous_address(NULL) { }
86 void set_previous(HeapWord* addr) { _previous_address = addr; }
87 HeapWord* previous() { return _previous_address; }
88 // A return value of "true" can be used by the caller to decide
89 // if this object's end should *NOT* be recorded in
90 // _previous_address above.
91 virtual bool do_object_bm(oop obj, MemRegion mr) = 0;
92 };
93
94 // A version of ObjectClosure that is expected to be robust
95 // in the face of possibly uninitialized objects.
96 class ObjectClosureCareful : public ObjectClosure {
97 public:
98 virtual size_t do_object_careful_m(oop p, MemRegion mr) = 0;
99 virtual size_t do_object_careful(oop p) = 0;
100 };
101
102 // The following are used in CompactibleFreeListSpace and
103 // ConcurrentMarkSweepGeneration.
104
105 // Blk closure (abstract class)
106 class BlkClosure : public StackObj {
107 public:
108 virtual size_t do_blk(HeapWord* addr) = 0;
109 };
110
111 // A version of BlkClosure that is expected to be robust
112 // in the face of possibly uninitialized objects.
113 class BlkClosureCareful : public BlkClosure {
114 public:
115 size_t do_blk(HeapWord* addr) {
116 guarantee(false, "call do_blk_careful instead");
117 return 0;
118 }
119 virtual size_t do_blk_careful(HeapWord* addr) = 0;
120 };
121
122 // SpaceClosure is used for iterating over spaces
123
124 class Space;
125 class CompactibleSpace;
126
127 class SpaceClosure : public StackObj {
128 public:
129 // Called for each space
130 virtual void do_space(Space* s) = 0;
131 };
132
133 class CompactibleSpaceClosure : public StackObj {
134 public:
135 // Called for each compactible space
136 virtual void do_space(CompactibleSpace* s) = 0;
137 };
138
139
140
141 // MonitorClosure is used for iterating over monitors in the monitors cache
142
143 class ObjectMonitor;
144
145 class MonitorClosure : public StackObj {
146 public:
147 // called for each monitor in cache
148 virtual void do_monitor(ObjectMonitor* m) = 0;
149 };
150
151 // A closure that is applied without any arguments.
152 class VoidClosure : public StackObj {
153 public:
154 // I would have liked to declare this a pure virtual, but that breaks
155 // in mysterious ways, for unknown reasons.
156 virtual void do_void();
157 };
158
159
160 // YieldClosure is intended for use by iteration loops
161 // to incrementalize their work, allowing interleaving
162 // of an interruptable task so as to allow other
163 // threads to run (which may not otherwise be able to access
164 // exclusive resources, for instance). Additionally, the
165 // closure also allows for aborting an ongoing iteration
166 // by means of checking the return value from the polling
167 // call.
168 class YieldClosure : public StackObj {
169 public:
170 virtual bool should_return() = 0;
171 };
172
173 // Abstract closure for serializing data (read or write).
174
175 class SerializeOopClosure : public OopClosure {
176 public:
177 // Return bool indicating whether closure implements read or write.
178 virtual bool reading() const = 0;
179
180 // Read/write the int pointed to by i.
181 virtual void do_int(int* i) = 0;
182
183 // Read/write the size_t pointed to by i.
184 virtual void do_size_t(size_t* i) = 0;
185
186 // Read/write the void pointer pointed to by p.
187 virtual void do_ptr(void** p) = 0;
188
189 // Read/write the HeapWord pointer pointed to be p.
190 virtual void do_ptr(HeapWord** p) = 0;
191
192 // Read/write the region specified.
193 virtual void do_region(u_char* start, size_t size) = 0;
194
195 // Check/write the tag. If reading, then compare the tag against
196 // the passed in value and fail is they don't match. This allows
197 // for verification that sections of the serialized data are of the
198 // correct length.
199 virtual void do_tag(int tag) = 0;
200 };