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
45 template <typename item_t, typename lock_t>
46 struct hb_lockable_set_t
47 {
48 hb_vector_t<item_t> items;
49
inithb_lockable_set_t50 void init () { items.init (); }
51
52 template <typename T>
replace_or_inserthb_lockable_set_t53 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 item;
73 }
74
75 template <typename T>
removehb_lockable_set_t76 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>
findhb_lockable_set_t93 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>
find_or_inserthb_lockable_set_t104 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
finihb_lockable_set_t115 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
143 struct hb_reference_count_t
144 {
145 mutable hb_atomic_int_t ref_count;
146
inithb_reference_count_t147 void init (int v = 1) { ref_count = v; }
get_relaxedhb_reference_count_t148 int get_relaxed () const { return ref_count; }
inchb_reference_count_t149 int inc () const { return ref_count.inc (); }
dechb_reference_count_t150 int dec () const { return ref_count.dec (); }
finihb_reference_count_t151 void fini () { ref_count = -0x0000DEAD; }
152
is_inerthb_reference_count_t153 bool is_inert () const { return !ref_count; }
is_validhb_reference_count_t154 bool is_valid () const { return ref_count > 0; }
155 };
156
157
158 /* user_data */
159
160 struct 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
operator ==hb_user_data_array_t::hb_user_data_item_t167 bool operator == (const hb_user_data_key_t *other_key) const { return key == other_key; }
operator ==hb_user_data_array_t::hb_user_data_item_t168 bool operator == (const hb_user_data_item_t &other) const { return key == other.key; }
169
finihb_user_data_array_t::hb_user_data_item_t170 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
inithb_user_data_array_t176 void init () { lock.init (); items.init (); }
177
178 HB_INTERNAL bool set (hb_user_data_key_t *key,
179 void * data,
180 hb_destroy_func_t destroy,
181 hb_bool_t replace);
182
183 HB_INTERNAL void *get (hb_user_data_key_t *key);
184
finihb_user_data_array_t185 void fini () { items.fini (lock); lock.fini (); }
186 };
187
188
189 /*
190 * Object header
191 */
192
193 struct hb_object_header_t
194 {
195 hb_reference_count_t ref_count;
196 mutable hb_atomic_int_t writable = 0;
197 hb_atomic_ptr_t<hb_user_data_array_t> user_data;
198
is_inerthb_object_header_t199 bool is_inert () const { return !ref_count.get_relaxed (); }
200 };
201 #define HB_OBJECT_HEADER_STATIC {}
202
203
204 /*
205 * Object
206 */
207
208 template <typename Type>
hb_object_trace(const Type * obj,const char * function)209 static inline void hb_object_trace (const Type *obj, const char *function)
210 {
211 DEBUG_MSG (OBJECT, (void *) obj,
212 "%s refcount=%d",
213 function,
214 obj ? obj->header.ref_count.get_relaxed () : 0);
215 }
216
217 template <typename Type, typename ...Ts>
hb_object_create(Ts...ds)218 static inline Type *hb_object_create (Ts... ds)
219 {
220 Type *obj = (Type *) hb_calloc (1, sizeof (Type));
221
222 if (unlikely (!obj))
223 return obj;
224
225 new (obj) Type (std::forward<Ts> (ds)...);
226
227 hb_object_init (obj);
228 hb_object_trace (obj, HB_FUNC);
229
230 return obj;
231 }
232 template <typename Type>
hb_object_init(Type * obj)233 static inline void hb_object_init (Type *obj)
234 {
235 obj->header.ref_count.init ();
236 obj->header.writable = true;
237 obj->header.user_data.init ();
238 }
239 template <typename Type>
hb_object_is_valid(const Type * obj)240 static inline bool hb_object_is_valid (const Type *obj)
241 {
242 return likely (obj->header.ref_count.is_valid ());
243 }
244 template <typename Type>
hb_object_is_immutable(const Type * obj)245 static inline bool hb_object_is_immutable (const Type *obj)
246 {
247 return !obj->header.writable;
248 }
249 template <typename Type>
hb_object_make_immutable(const Type * obj)250 static inline void hb_object_make_immutable (const Type *obj)
251 {
252 obj->header.writable = false;
253 }
254 template <typename Type>
hb_object_reference(Type * obj)255 static inline Type *hb_object_reference (Type *obj)
256 {
257 hb_object_trace (obj, HB_FUNC);
258 if (unlikely (!obj || obj->header.is_inert ()))
259 return obj;
260 assert (hb_object_is_valid (obj));
261 obj->header.ref_count.inc ();
262 return obj;
263 }
264 template <typename Type>
hb_object_destroy(Type * obj)265 static inline bool hb_object_destroy (Type *obj)
266 {
267 hb_object_trace (obj, HB_FUNC);
268 if (unlikely (!obj || obj->header.is_inert ()))
269 return false;
270 assert (hb_object_is_valid (obj));
271 if (obj->header.ref_count.dec () != 1)
272 return false;
273
274 hb_object_fini (obj);
275
276 if (!std::is_trivially_destructible<Type>::value)
277 obj->~Type ();
278
279 return true;
280 }
281 template <typename Type>
hb_object_fini(Type * obj)282 static inline void hb_object_fini (Type *obj)
283 {
284 obj->header.ref_count.fini (); /* Do this before user_data */
285 hb_user_data_array_t *user_data = obj->header.user_data.get_acquire ();
286 if (user_data)
287 {
288 user_data->fini ();
289 hb_free (user_data);
290 obj->header.user_data.set_relaxed (nullptr);
291 }
292 }
293 template <typename Type>
hb_object_set_user_data(Type * obj,hb_user_data_key_t * key,void * data,hb_destroy_func_t destroy,hb_bool_t replace)294 static inline bool hb_object_set_user_data (Type *obj,
295 hb_user_data_key_t *key,
296 void * data,
297 hb_destroy_func_t destroy,
298 hb_bool_t replace)
299 {
300 if (unlikely (!obj || obj->header.is_inert ()))
301 return false;
302 assert (hb_object_is_valid (obj));
303
304 retry:
305 hb_user_data_array_t *user_data = obj->header.user_data.get_acquire ();
306 if (unlikely (!user_data))
307 {
308 user_data = (hb_user_data_array_t *) hb_calloc (sizeof (hb_user_data_array_t), 1);
309 if (unlikely (!user_data))
310 return false;
311 user_data->init ();
312 if (unlikely (!obj->header.user_data.cmpexch (nullptr, user_data)))
313 {
314 user_data->fini ();
315 hb_free (user_data);
316 goto retry;
317 }
318 }
319
320 return user_data->set (key, data, destroy, replace);
321 }
322
323 template <typename Type>
hb_object_get_user_data(Type * obj,hb_user_data_key_t * key)324 static inline void *hb_object_get_user_data (Type *obj,
325 hb_user_data_key_t *key)
326 {
327 if (unlikely (!obj || obj->header.is_inert ()))
328 return nullptr;
329 assert (hb_object_is_valid (obj));
330 hb_user_data_array_t *user_data = obj->header.user_data.get_acquire ();
331 if (!user_data)
332 return nullptr;
333 return user_data->get (key);
334 }
335
336
337 #endif /* HB_OBJECT_HH */
338