1 /*
2 +----------------------------------------------------------------------+
3 | Zend Engine |
4 +----------------------------------------------------------------------+
5 | Copyright (c) 1998-2018 Zend Technologies Ltd. (http://www.zend.com) |
6 +----------------------------------------------------------------------+
7 | This source file is subject to version 2.00 of the Zend license, |
8 | that is bundled with this package in the file LICENSE, and is |
9 | available through the world-wide-web at the following url: |
10 | http://www.zend.com/license/2_00.txt. |
11 | If you did not receive a copy of the Zend license and are unable to |
12 | obtain it through the world-wide-web, please send a note to |
13 | license@zend.com so we can mail you a copy immediately. |
14 +----------------------------------------------------------------------+
15 | Authors: Dmitry Stogov <dmitry@zend.com> |
16 +----------------------------------------------------------------------+
17 */
18
19 /* $Id: $ */
20
21 #include "zend.h"
22 #include "zend_globals.h"
23
24 ZEND_API zend_string *(*zend_new_interned_string)(zend_string *str);
25
26 static zend_string *zend_new_interned_string_permanent(zend_string *str);
27 static zend_string *zend_new_interned_string_request(zend_string *str);
28
29 /* Any strings interned in the startup phase. Common to all the threads,
30 won't be free'd until process exit. If we want an ability to
31 add permanent strings even after startup, it would be still
32 possible on costs of locking in the thread safe builds. */
33 static HashTable interned_strings_permanent;
34
35 static zend_new_interned_string_func_t interned_string_request_handler = zend_new_interned_string_request;
36 static zend_string_copy_storage_func_t interned_string_copy_storage = NULL;
37
38 ZEND_API zend_string *zend_empty_string = NULL;
39 ZEND_API zend_string *zend_one_char_string[256];
40 ZEND_API zend_string **zend_known_strings = NULL;
41
zend_hash_func(const char * str,size_t len)42 ZEND_API zend_ulong zend_hash_func(const char *str, size_t len)
43 {
44 return zend_inline_hash_func(str, len);
45 }
46
_str_dtor(zval * zv)47 static void _str_dtor(zval *zv)
48 {
49 zend_string *str = Z_STR_P(zv);
50 pefree(str, GC_FLAGS(str) & IS_STR_PERSISTENT);
51 }
52
53 static const char *known_strings[] = {
54 #define _ZEND_STR_DSC(id, str) str,
55 ZEND_KNOWN_STRINGS(_ZEND_STR_DSC)
56 #undef _ZEND_STR_DSC
57 NULL
58 };
59
zend_init_interned_strings_ht(HashTable * interned_strings,int permanent)60 static void zend_init_interned_strings_ht(HashTable *interned_strings, int permanent)
61 {
62 zend_hash_init(interned_strings, 1024, NULL, _str_dtor, permanent);
63 zend_hash_real_init(interned_strings, 0);
64 }
65
zend_interned_strings_init(void)66 ZEND_API void zend_interned_strings_init(void)
67 {
68 char s[2];
69 int i;
70 zend_string *str;
71
72 interned_string_request_handler = zend_new_interned_string_request;
73 interned_string_copy_storage = NULL;
74
75 zend_empty_string = NULL;
76 zend_known_strings = NULL;
77
78 zend_init_interned_strings_ht(&interned_strings_permanent, 1);
79
80 zend_new_interned_string = zend_new_interned_string_permanent;
81
82 /* interned empty string */
83 str = zend_string_alloc(sizeof("")-1, 1);
84 ZSTR_VAL(str)[0] = '\000';
85 zend_empty_string = zend_new_interned_string_permanent(str);
86
87 s[1] = 0;
88 for (i = 0; i < 256; i++) {
89 s[0] = i;
90 zend_one_char_string[i] = zend_new_interned_string_permanent(zend_string_init(s, 1, 1));
91 }
92
93 /* known strings */
94 zend_known_strings = pemalloc(sizeof(zend_string*) * ((sizeof(known_strings) / sizeof(known_strings[0]) - 1)), 1);
95 for (i = 0; i < (sizeof(known_strings) / sizeof(known_strings[0])) - 1; i++) {
96 str = zend_string_init(known_strings[i], strlen(known_strings[i]), 1);
97 zend_known_strings[i] = zend_new_interned_string_permanent(str);
98 }
99 }
100
zend_interned_strings_dtor(void)101 ZEND_API void zend_interned_strings_dtor(void)
102 {
103 zend_hash_destroy(&interned_strings_permanent);
104
105 free(zend_known_strings);
106 zend_known_strings = NULL;
107 }
108
zend_interned_string_ht_lookup(zend_string * str,HashTable * interned_strings)109 static zend_always_inline zend_string *zend_interned_string_ht_lookup(zend_string *str, HashTable *interned_strings)
110 {
111 zend_ulong h;
112 uint32_t nIndex;
113 uint32_t idx;
114 Bucket *p;
115
116 h = zend_string_hash_val(str);
117 nIndex = h | interned_strings->nTableMask;
118 idx = HT_HASH(interned_strings, nIndex);
119 while (idx != HT_INVALID_IDX) {
120 p = HT_HASH_TO_BUCKET(interned_strings, idx);
121 if ((p->h == h) && (ZSTR_LEN(p->key) == ZSTR_LEN(str))) {
122 if (!memcmp(ZSTR_VAL(p->key), ZSTR_VAL(str), ZSTR_LEN(str))) {
123 return p->key;
124 }
125 }
126 idx = Z_NEXT(p->val);
127 }
128
129 return NULL;
130 }
131
132 /* This function might be not thread safe at least because it would update the
133 hash val in the passed string. Be sure it is called in the appropriate context. */
zend_add_interned_string(zend_string * str,HashTable * interned_strings,uint32_t flags)134 static zend_always_inline zend_string *zend_add_interned_string(zend_string *str, HashTable *interned_strings, uint32_t flags)
135 {
136 zval val;
137
138 GC_REFCOUNT(str) = 1;
139 GC_FLAGS(str) |= IS_STR_INTERNED | flags;
140
141 ZVAL_INTERNED_STR(&val, str);
142
143 zend_hash_add_new(interned_strings, str, &val);
144
145 return str;
146 }
147
zend_interned_string_find_permanent(zend_string * str)148 ZEND_API zend_string *zend_interned_string_find_permanent(zend_string *str)
149 {
150 return zend_interned_string_ht_lookup(str, &interned_strings_permanent);
151 }
152
153
zend_new_interned_string_permanent(zend_string * str)154 static zend_string *zend_new_interned_string_permanent(zend_string *str)
155 {
156 zend_string *ret;
157
158 if (ZSTR_IS_INTERNED(str)) {
159 return str;
160 }
161
162 ret = zend_interned_string_ht_lookup(str, &interned_strings_permanent);
163 if (ret) {
164 zend_string_release(str);
165 return ret;
166 }
167
168 return zend_add_interned_string(str, &interned_strings_permanent, IS_STR_PERMANENT);
169 }
170
zend_new_interned_string_request(zend_string * str)171 static zend_string *zend_new_interned_string_request(zend_string *str)
172 {
173 zend_string *ret;
174
175 if (ZSTR_IS_INTERNED(str)) {
176 return str;
177 }
178
179 /* Check for permanent strings, the table is readonly at this point. */
180 ret = zend_interned_string_ht_lookup(str, &interned_strings_permanent);
181 if (ret) {
182 zend_string_release(str);
183 return ret;
184 }
185
186 ret = zend_interned_string_ht_lookup(str, &CG(interned_strings));
187 if (ret) {
188 zend_string_release(str);
189 return ret;
190 }
191
192 /* Create a short living interned, freed after the request. */
193 ret = zend_add_interned_string(str, &CG(interned_strings), 0);
194
195 return ret;
196 }
197
zend_interned_strings_activate(void)198 ZEND_API void zend_interned_strings_activate(void)
199 {
200 zend_init_interned_strings_ht(&CG(interned_strings), 0);
201 }
202
zend_interned_strings_deactivate(void)203 ZEND_API void zend_interned_strings_deactivate(void)
204 {
205 zend_hash_destroy(&CG(interned_strings));
206 }
207
zend_interned_strings_set_request_storage_handler(zend_new_interned_string_func_t handler)208 ZEND_API void zend_interned_strings_set_request_storage_handler(zend_new_interned_string_func_t handler)
209 {
210 interned_string_request_handler = handler;
211 }
212
zend_interned_strings_set_permanent_storage_copy_handler(zend_string_copy_storage_func_t handler)213 ZEND_API void zend_interned_strings_set_permanent_storage_copy_handler(zend_string_copy_storage_func_t handler)
214 {
215 interned_string_copy_storage = handler;
216 }
217
zend_interned_strings_switch_storage(void)218 ZEND_API void zend_interned_strings_switch_storage(void)
219 {
220 if (interned_string_copy_storage) {
221 interned_string_copy_storage();
222 }
223 zend_new_interned_string = interned_string_request_handler;
224 }
225
226 /*
227 * Local variables:
228 * tab-width: 4
229 * c-basic-offset: 4
230 * indent-tabs-mode: t
231 * End:
232 * vim600: sw=4 ts=4 fdm=marker
233 * vim<600: sw=4 ts=4
234 */
235
