1/*
2 * Copyright © 2007 Chris Wilson
3 * Copyright © 2009,2010 Red Hat, Inc.
4 * Copyright © 2011,2012 Google, Inc.
5 *
6 * This is part of HarfBuzz, a text shaping library.
7 *
8 * Permission is hereby granted, without written agreement and without
9 * license or royalty fees, to use, copy, modify, and distribute this
10 * software and its documentation for any purpose, provided that the
11 * above copyright notice and the following two paragraphs appear in
12 * all copies of this software.
13 *
14 * IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR
15 * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
16 * ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN
17 * IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH
18 * DAMAGE.
19 *
20 * THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING,
21 * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
22 * FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE PROVIDED HEREUNDER IS
23 * ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO
24 * PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
25 *
26 * Contributor(s):
27 * Chris Wilson <chris@chris-wilson.co.uk>
28 * Red Hat Author(s): Behdad Esfahbod
29 * Google Author(s): Behdad Esfahbod
30 */
31
32#ifndef HB_OBJECT_HH
33#define HB_OBJECT_HH
34
35#include "hb.hh"
36#include "hb-atomic.hh"
37#include "hb-mutex.hh"
38#include "hb-vector.hh"
39
40
41/*
42 * Lockable set
43 */
44
45template <typename item_t, typename lock_t>
46struct hb_lockable_set_t
47{
48 hb_vector_t<item_t> items;
49
50 void init () { items.init (); }
51
52 template <typename T>
53 item_t *replace_or_insert (T v, lock_t &l, bool replace)
54 {
55 l.lock ();
56 item_t *item = items.find (v);
57 if (item) {
58 if (replace) {
59 item_t old = *item;
60 *item = v;
61 l.unlock ();
62 old.fini ();
63 }
64 else {
65 item = nullptr;
66 l.unlock ();
67 }
68 } else {
69 item = items.push (v);
70 l.unlock ();
71 }
72 return item;
73 }
74
75 template <typename T>
76 void remove (T v, lock_t &l)
77 {
78 l.lock ();
79 item_t *item = items.find (v);
80 if (item)
81 {
82 item_t old = *item;
83 *item = items[items.length - 1];
84 items.pop ();
85 l.unlock ();
86 old.fini ();
87 } else {
88 l.unlock ();
89 }
90 }
91
92 template <typename T>
93 bool find (T v, item_t *i, lock_t &l)
94 {
95 l.lock ();
96 item_t *item = items.find (v);
97 if (item)
98 *i = *item;
99 l.unlock ();
100 return !!item;
101 }
102
103 template <typename T>
104 item_t *find_or_insert (T v, lock_t &l)
105 {
106 l.lock ();
107 item_t *item = items.find (v);
108 if (!item) {
109 item = items.push (v);
110 }
111 l.unlock ();
112 return item;
113 }
114
115 void fini (lock_t &l)
116 {
117 if (!items.length)
118 {
119 /* No need to lock. */
120 items.fini ();
121 return;
122 }
123 l.lock ();
124 while (items.length)
125 {
126 item_t old = items[items.length - 1];
127 items.pop ();
128 l.unlock ();
129 old.fini ();
130 l.lock ();
131 }
132 items.fini ();
133 l.unlock ();
134 }
135
136};
137
138
139/*
140 * Reference-count.
141 */
142
143#define HB_REFERENCE_COUNT_INERT_VALUE 0
144#define HB_REFERENCE_COUNT_POISON_VALUE -0x0000DEAD
145#define HB_REFERENCE_COUNT_INIT {HB_ATOMIC_INT_INIT (HB_REFERENCE_COUNT_INERT_VALUE)}
146
147struct hb_reference_count_t
148{
149 mutable hb_atomic_int_t ref_count;
150
151 void init (int v = 1) { ref_count.set_relaxed (v); }
152 int get_relaxed () const { return ref_count.get_relaxed (); }
153 int inc () const { return ref_count.inc (); }
154 int dec () const { return ref_count.dec (); }
155 void fini () { ref_count.set_relaxed (HB_REFERENCE_COUNT_POISON_VALUE); }
156
157 bool is_inert () const { return ref_count.get_relaxed () == HB_REFERENCE_COUNT_INERT_VALUE; }
158 bool is_valid () const { return ref_count.get_relaxed () > 0; }
159};
160
161
162/* user_data */
163
164struct hb_user_data_array_t
165{
166 struct hb_user_data_item_t {
167 hb_user_data_key_t *key;
168 void *data;
169 hb_destroy_func_t destroy;
170
171 bool operator == (const hb_user_data_key_t *other_key) const { return key == other_key; }
172 bool operator == (const hb_user_data_item_t &other) const { return key == other.key; }
173
174 void fini () { if (destroy) destroy (data); }
175 };
176
177 hb_mutex_t lock;
178 hb_lockable_set_t<hb_user_data_item_t, hb_mutex_t> items;
179
180 void init () { lock.init (); items.init (); }
181
182 HB_INTERNAL bool set (hb_user_data_key_t *key,
183 void * data,
184 hb_destroy_func_t destroy,
185 hb_bool_t replace);
186
187 HB_INTERNAL void *get (hb_user_data_key_t *key);
188
189 void fini () { items.fini (lock); lock.fini (); }
190};
191
192
193/*
194 * Object header
195 */
196
197struct hb_object_header_t
198{
199 hb_reference_count_t ref_count;
200 mutable hb_atomic_int_t writable;
201 hb_atomic_ptr_t<hb_user_data_array_t> user_data;
202};
203#define HB_OBJECT_HEADER_STATIC \
204 { \
205 HB_REFERENCE_COUNT_INIT, \
206 HB_ATOMIC_INT_INIT (false), \
207 HB_ATOMIC_PTR_INIT (nullptr) \
208 }
209
210
211/*
212 * Object
213 */
214
215template <typename Type>
216static inline void hb_object_trace (const Type *obj, const char *function)
217{
218 DEBUG_MSG (OBJECT, (void *) obj,
219 "%s refcount=%d",
220 function,
221 obj ? obj->header.ref_count.get_relaxed () : 0);
222}
223
224template <typename Type>
225static inline Type *hb_object_create ()
226{
227 Type *obj = (Type *) calloc (1, sizeof (Type));
228
229 if (unlikely (!obj))
230 return obj;
231
232 hb_object_init (obj);
233 hb_object_trace (obj, HB_FUNC);
234 return obj;
235}
236template <typename Type>
237static inline void hb_object_init (Type *obj)
238{
239 obj->header.ref_count.init ();
240 obj->header.writable.set_relaxed (true);
241 obj->header.user_data.init ();
242}
243template <typename Type>
244static inline bool hb_object_is_inert (const Type *obj)
245{
246 return unlikely (obj->header.ref_count.is_inert ());
247}
248template <typename Type>
249static inline bool hb_object_is_valid (const Type *obj)
250{
251 return likely (obj->header.ref_count.is_valid ());
252}
253template <typename Type>
254static inline bool hb_object_is_immutable (const Type *obj)
255{
256 return !obj->header.writable.get_relaxed ();
257}
258template <typename Type>
259static inline void hb_object_make_immutable (const Type *obj)
260{
261 obj->header.writable.set_relaxed (false);
262}
263template <typename Type>
264static inline Type *hb_object_reference (Type *obj)
265{
266 hb_object_trace (obj, HB_FUNC);
267 if (unlikely (!obj || hb_object_is_inert (obj)))
268 return obj;
269 assert (hb_object_is_valid (obj));
270 obj->header.ref_count.inc ();
271 return obj;
272}
273template <typename Type>
274static inline bool hb_object_destroy (Type *obj)
275{
276 hb_object_trace (obj, HB_FUNC);
277 if (unlikely (!obj || hb_object_is_inert (obj)))
278 return false;
279 assert (hb_object_is_valid (obj));
280 if (obj->header.ref_count.dec () != 1)
281 return false;
282
283 hb_object_fini (obj);
284 return true;
285}
286template <typename Type>
287static inline void hb_object_fini (Type *obj)
288{
289 obj->header.ref_count.fini (); /* Do this before user_data */
290 hb_user_data_array_t *user_data = obj->header.user_data.get ();
291 if (user_data)
292 {
293 user_data->fini ();
294 free (user_data);
295 user_data = nullptr;
296 }
297}
298template <typename Type>
299static inline bool hb_object_set_user_data (Type *obj,
300 hb_user_data_key_t *key,
301 void * data,
302 hb_destroy_func_t destroy,
303 hb_bool_t replace)
304{
305 if (unlikely (!obj || hb_object_is_inert (obj)))
306 return false;
307 assert (hb_object_is_valid (obj));
308
309retry:
310 hb_user_data_array_t *user_data = obj->header.user_data.get ();
311 if (unlikely (!user_data))
312 {
313 user_data = (hb_user_data_array_t *) calloc (sizeof (hb_user_data_array_t), 1);
314 if (unlikely (!user_data))
315 return false;
316 user_data->init ();
317 if (unlikely (!obj->header.user_data.cmpexch (nullptr, user_data)))
318 {
319 user_data->fini ();
320 free (user_data);
321 goto retry;
322 }
323 }
324
325 return user_data->set (key, data, destroy, replace);
326}
327
328template <typename Type>
329static inline void *hb_object_get_user_data (Type *obj,
330 hb_user_data_key_t *key)
331{
332 if (unlikely (!obj || hb_object_is_inert (obj)))
333 return nullptr;
334 assert (hb_object_is_valid (obj));
335 hb_user_data_array_t *user_data = obj->header.user_data.get ();
336 if (!user_data)
337 return nullptr;
338 return user_data->get (key);
339}
340
341
342#endif /* HB_OBJECT_HH */
343