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.lsearch (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 items.in_error () ? nullptr : item;
73 }
74
75 template <typename T>
76 void remove (T v, lock_t &l)
77 {
78 l.lock ();
79 item_t *item = items.lsearch (v);
80 if (item)
81 {
82 item_t old = *item;
83 *item = std::move (items.tail ());
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.lsearch (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.tail ();
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
143struct hb_reference_count_t
144{
145 mutable hb_atomic_int_t ref_count;
146
147 void init (int v = 1) { ref_count = v; }
148 int get_relaxed () const { return ref_count; }
149 int inc () const { return ref_count.inc (); }
150 int dec () const { return ref_count.dec (); }
151 void fini () { ref_count = -0x0000DEAD; }
152
153 bool is_inert () const { return !ref_count; }
154 bool is_valid () const { return ref_count > 0; }
155};
156
157
158/* user_data */
159
160struct hb_user_data_array_t
161{
162 struct hb_user_data_item_t {
163 hb_user_data_key_t *key;
164 void *data;
165 hb_destroy_func_t destroy;
166
167 bool operator == (const hb_user_data_key_t *other_key) const { return key == other_key; }
168 bool operator == (const hb_user_data_item_t &other) const { return key == other.key; }
169
170 void fini () { if (destroy) destroy (data); }
171 };
172
173 hb_mutex_t lock;
174 hb_lockable_set_t<hb_user_data_item_t, hb_mutex_t> items;
175
176 void init () { lock.init (); items.init (); }
177
178 void fini () { items.fini (lock); lock.fini (); }
179
180 bool set (hb_user_data_key_t *key,
181 void * data,
182 hb_destroy_func_t destroy,
183 hb_bool_t replace)
184 {
185 if (!key)
186 return false;
187
188 if (replace) {
189 if (!data && !destroy) {
190 items.remove (key, lock);
191 return true;
192 }
193 }
194 hb_user_data_item_t item = {key, data, destroy};
195 bool ret = !!items.replace_or_insert (item, lock, (bool) replace);
196
197 return ret;
198 }
199
200 void *get (hb_user_data_key_t *key)
201 {
202 hb_user_data_item_t item = {nullptr, nullptr, nullptr};
203
204 return items.find (key, &item, lock) ? item.data : nullptr;
205 }
206};
207
208
209/*
210 * Object header
211 */
212
213struct hb_object_header_t
214{
215 hb_reference_count_t ref_count;
216 mutable hb_atomic_int_t writable = 0;
217 hb_atomic_ptr_t<hb_user_data_array_t> user_data;
218
219 bool is_inert () const { return !ref_count.get_relaxed (); }
220};
221#define HB_OBJECT_HEADER_STATIC {}
222
223
224/*
225 * Object
226 */
227
228template <typename Type>
229static inline void hb_object_trace (const Type *obj, const char *function)
230{
231 DEBUG_MSG (OBJECT, (void *) obj,
232 "%s refcount=%d",
233 function,
234 obj ? obj->header.ref_count.get_relaxed () : 0);
235}
236
237template <typename Type, typename ...Ts>
238static inline Type *hb_object_create (Ts... ds)
239{
240 Type *obj = (Type *) hb_calloc (1, sizeof (Type));
241
242 if (unlikely (!obj))
243 return obj;
244
245 new (obj) Type (std::forward<Ts> (ds)...);
246
247 hb_object_init (obj);
248 hb_object_trace (obj, HB_FUNC);
249
250 return obj;
251}
252template <typename Type>
253static inline void hb_object_init (Type *obj)
254{
255 obj->header.ref_count.init ();
256 obj->header.writable = true;
257 obj->header.user_data.init ();
258}
259template <typename Type>
260static inline bool hb_object_is_valid (const Type *obj)
261{
262 return likely (obj->header.ref_count.is_valid ());
263}
264template <typename Type>
265static inline bool hb_object_is_immutable (const Type *obj)
266{
267 return !obj->header.writable;
268}
269template <typename Type>
270static inline void hb_object_make_immutable (const Type *obj)
271{
272 obj->header.writable = false;
273}
274template <typename Type>
275static inline Type *hb_object_reference (Type *obj)
276{
277 hb_object_trace (obj, HB_FUNC);
278 if (unlikely (!obj || obj->header.is_inert ()))
279 return obj;
280 assert (hb_object_is_valid (obj));
281 obj->header.ref_count.inc ();
282 return obj;
283}
284template <typename Type>
285static inline bool hb_object_destroy (Type *obj)
286{
287 hb_object_trace (obj, HB_FUNC);
288 if (unlikely (!obj || obj->header.is_inert ()))
289 return false;
290 assert (hb_object_is_valid (obj));
291 if (obj->header.ref_count.dec () != 1)
292 return false;
293
294 hb_object_fini (obj);
295
296 if (!std::is_trivially_destructible<Type>::value)
297 obj->~Type ();
298
299 return true;
300}
301template <typename Type>
302static inline void hb_object_fini (Type *obj)
303{
304 obj->header.ref_count.fini (); /* Do this before user_data */
305 hb_user_data_array_t *user_data = obj->header.user_data.get_acquire ();
306 if (user_data)
307 {
308 user_data->fini ();
309 hb_free (user_data);
310 obj->header.user_data.set_relaxed (nullptr);
311 }
312}
313template <typename Type>
314static inline bool hb_object_set_user_data (Type *obj,
315 hb_user_data_key_t *key,
316 void * data,
317 hb_destroy_func_t destroy,
318 hb_bool_t replace)
319{
320 if (unlikely (!obj || obj->header.is_inert ()))
321 return false;
322 assert (hb_object_is_valid (obj));
323
324retry:
325 hb_user_data_array_t *user_data = obj->header.user_data.get_acquire ();
326 if (unlikely (!user_data))
327 {
328 user_data = (hb_user_data_array_t *) hb_calloc (sizeof (hb_user_data_array_t), 1);
329 if (unlikely (!user_data))
330 return false;
331 user_data->init ();
332 if (unlikely (!obj->header.user_data.cmpexch (nullptr, user_data)))
333 {
334 user_data->fini ();
335 hb_free (user_data);
336 goto retry;
337 }
338 }
339
340 return user_data->set (key, data, destroy, replace);
341}
342
343template <typename Type>
344static inline void *hb_object_get_user_data (Type *obj,
345 hb_user_data_key_t *key)
346{
347 if (unlikely (!obj || obj->header.is_inert ()))
348 return nullptr;
349 assert (hb_object_is_valid (obj));
350 hb_user_data_array_t *user_data = obj->header.user_data.get_acquire ();
351 if (!user_data)
352 return nullptr;
353 return user_data->get (key);
354}
355
356
357#endif /* HB_OBJECT_HH */
358