1 /* Copyright libuv project contributors. All rights reserved.
2 *
3 * Permission is hereby granted, free of charge, to any person obtaining a copy
4 * of this software and associated documentation files (the "Software"), to
5 * deal in the Software without restriction, including without limitation the
6 * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
7 * sell copies of the Software, and to permit persons to whom the Software is
8 * furnished to do so, subject to the following conditions:
9 *
10 * The above copyright notice and this permission notice shall be included in
11 * all copies or substantial portions of the Software.
12 *
13 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
14 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
15 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
16 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
17 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
18 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
19 * IN THE SOFTWARE.
20 */
21
22 #ifndef UV_WIN_FS_FD_HASH_INL_H_
23 #define UV_WIN_FS_FD_HASH_INL_H_
24
25 #include "uv.h"
26 #include "internal.h"
27
28 /* Files are only inserted in uv__fd_hash when the UV_FS_O_FILEMAP flag is
29 * specified. Thus, when uv__fd_hash_get returns true, the file mapping in the
30 * info structure should be used for read/write operations.
31 *
32 * If the file is empty, the mapping field will be set to
33 * INVALID_HANDLE_VALUE. This is not an issue since the file mapping needs to
34 * be created anyway when the file size changes.
35 *
36 * Since file descriptors are sequential integers, the modulo operator is used
37 * as hashing function. For each bucket, a single linked list of arrays is
38 * kept to minimize allocations. A statically allocated memory buffer is kept
39 * for the first array in each bucket. */
40
41
42 #define UV__FD_HASH_SIZE 256
43 #define UV__FD_HASH_GROUP_SIZE 16
44
45 struct uv__fd_info_s {
46 int flags;
47 BOOLEAN is_directory;
48 HANDLE mapping;
49 LARGE_INTEGER size;
50 LARGE_INTEGER current_pos;
51 };
52
53 struct uv__fd_hash_entry_s {
54 uv_file fd;
55 struct uv__fd_info_s info;
56 };
57
58 struct uv__fd_hash_entry_group_s {
59 struct uv__fd_hash_entry_s entries[UV__FD_HASH_GROUP_SIZE];
60 struct uv__fd_hash_entry_group_s* next;
61 };
62
63 struct uv__fd_hash_bucket_s {
64 size_t size;
65 struct uv__fd_hash_entry_group_s* data;
66 };
67
68
69 static uv_mutex_t uv__fd_hash_mutex;
70
71 static struct uv__fd_hash_entry_group_s
72 uv__fd_hash_entry_initial[UV__FD_HASH_SIZE * UV__FD_HASH_GROUP_SIZE];
73 static struct uv__fd_hash_bucket_s uv__fd_hash[UV__FD_HASH_SIZE];
74
75
uv__fd_hash_init(void)76 INLINE static void uv__fd_hash_init(void) {
77 size_t i;
78 int err;
79
80 err = uv_mutex_init(&uv__fd_hash_mutex);
81 if (err) {
82 uv_fatal_error(err, "uv_mutex_init");
83 }
84
85 for (i = 0; i < ARRAY_SIZE(uv__fd_hash); ++i) {
86 uv__fd_hash[i].size = 0;
87 uv__fd_hash[i].data =
88 uv__fd_hash_entry_initial + i * UV__FD_HASH_GROUP_SIZE;
89 }
90 }
91
92 #define FIND_COMMON_VARIABLES \
93 unsigned i; \
94 unsigned bucket = fd % ARRAY_SIZE(uv__fd_hash); \
95 struct uv__fd_hash_entry_s* entry_ptr = NULL; \
96 struct uv__fd_hash_entry_group_s* group_ptr; \
97 struct uv__fd_hash_bucket_s* bucket_ptr = &uv__fd_hash[bucket];
98
99 #define FIND_IN_GROUP_PTR(group_size) \
100 do { \
101 for (i = 0; i < group_size; ++i) { \
102 if (group_ptr->entries[i].fd == fd) { \
103 entry_ptr = &group_ptr->entries[i]; \
104 break; \
105 } \
106 } \
107 } while (0)
108
109 #define FIND_IN_BUCKET_PTR() \
110 do { \
111 size_t first_group_size = bucket_ptr->size % UV__FD_HASH_GROUP_SIZE; \
112 if (bucket_ptr->size != 0 && first_group_size == 0) \
113 first_group_size = UV__FD_HASH_GROUP_SIZE; \
114 group_ptr = bucket_ptr->data; \
115 FIND_IN_GROUP_PTR(first_group_size); \
116 for (group_ptr = group_ptr->next; \
117 group_ptr != NULL && entry_ptr == NULL; \
118 group_ptr = group_ptr->next) \
119 FIND_IN_GROUP_PTR(UV__FD_HASH_GROUP_SIZE); \
120 } while (0)
121
uv__fd_hash_get(int fd,struct uv__fd_info_s * info)122 INLINE static int uv__fd_hash_get(int fd, struct uv__fd_info_s* info) {
123 FIND_COMMON_VARIABLES
124
125 uv_mutex_lock(&uv__fd_hash_mutex);
126
127 FIND_IN_BUCKET_PTR();
128
129 if (entry_ptr != NULL) {
130 *info = entry_ptr->info;
131 }
132
133 uv_mutex_unlock(&uv__fd_hash_mutex);
134 return entry_ptr != NULL;
135 }
136
uv__fd_hash_add(int fd,struct uv__fd_info_s * info)137 INLINE static void uv__fd_hash_add(int fd, struct uv__fd_info_s* info) {
138 FIND_COMMON_VARIABLES
139
140 uv_mutex_lock(&uv__fd_hash_mutex);
141
142 FIND_IN_BUCKET_PTR();
143
144 if (entry_ptr == NULL) {
145 i = bucket_ptr->size % UV__FD_HASH_GROUP_SIZE;
146
147 if (bucket_ptr->size != 0 && i == 0) {
148 struct uv__fd_hash_entry_group_s* new_group_ptr =
149 uv__malloc(sizeof(*new_group_ptr));
150 if (new_group_ptr == NULL) {
151 uv_fatal_error(ERROR_OUTOFMEMORY, "uv__malloc");
152 }
153 new_group_ptr->next = bucket_ptr->data;
154 bucket_ptr->data = new_group_ptr;
155 }
156
157 bucket_ptr->size += 1;
158 entry_ptr = &bucket_ptr->data->entries[i];
159 entry_ptr->fd = fd;
160 }
161
162 entry_ptr->info = *info;
163
164 uv_mutex_unlock(&uv__fd_hash_mutex);
165 }
166
uv__fd_hash_remove(int fd,struct uv__fd_info_s * info)167 INLINE static int uv__fd_hash_remove(int fd, struct uv__fd_info_s* info) {
168 FIND_COMMON_VARIABLES
169
170 uv_mutex_lock(&uv__fd_hash_mutex);
171
172 FIND_IN_BUCKET_PTR();
173
174 if (entry_ptr != NULL) {
175 *info = entry_ptr->info;
176
177 bucket_ptr->size -= 1;
178
179 i = bucket_ptr->size % UV__FD_HASH_GROUP_SIZE;
180 if (entry_ptr != &bucket_ptr->data->entries[i]) {
181 *entry_ptr = bucket_ptr->data->entries[i];
182 }
183
184 if (bucket_ptr->size != 0 &&
185 bucket_ptr->size % UV__FD_HASH_GROUP_SIZE == 0) {
186 struct uv__fd_hash_entry_group_s* old_group_ptr = bucket_ptr->data;
187 bucket_ptr->data = old_group_ptr->next;
188 uv__free(old_group_ptr);
189 }
190 }
191
192 uv_mutex_unlock(&uv__fd_hash_mutex);
193 return entry_ptr != NULL;
194 }
195
196 #undef FIND_COMMON_VARIABLES
197 #undef FIND_IN_GROUP_PTR
198 #undef FIND_IN_BUCKET_PTR
199
200 #endif /* UV_WIN_FS_FD_HASH_INL_H_ */
201
