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1 | /* |
2 | * Copyright (c) 2013 Nicira, Inc. | |
3 | * | |
4 | * Licensed under the Apache License, Version 2.0 (the "License"); | |
5 | * you may not use this file except in compliance with the License. | |
6 | * You may obtain a copy of the License at: | |
7 | * | |
8 | * http://www.apache.org/licenses/LICENSE-2.0 | |
9 | * | |
10 | * Unless required by applicable law or agreed to in writing, software | |
11 | * distributed under the License is distributed on an "AS IS" BASIS, | |
12 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. | |
13 | * See the License for the specific language governing permissions and | |
14 | * limitations under the License. | |
15 | */ | |
16 | ||
17 | #include <config.h> | |
18 | ||
19 | #include "latch.h" | |
20 | #include <errno.h> | |
21 | #include <poll.h> | |
22 | #include <unistd.h> | |
23 | #include "poll-loop.h" | |
24 | #include "socket-util.h" | |
25 | ||
26 | /* Initializes 'latch' as initially unset. */ | |
27 | void | |
28 | latch_init(struct latch *latch) | |
29 | { | |
30 | latch->is_set = FALSE; | |
31 | latch->wevent = CreateEvent(NULL, TRUE, FALSE, NULL); | |
32 | } | |
33 | ||
34 | /* Destroys 'latch'. */ | |
35 | void | |
36 | latch_destroy(struct latch *latch) | |
37 | { | |
38 | latch->is_set = FALSE; | |
39 | CloseHandle(latch->wevent); | |
40 | } | |
41 | ||
42 | /* Resets 'latch' to the unset state. Returns true if 'latch' was previously | |
43 | * set, false otherwise. */ | |
44 | bool | |
45 | latch_poll(struct latch *latch) | |
46 | { | |
47 | bool is_set; | |
48 | ||
49 | is_set = latch->is_set; | |
50 | latch->is_set = FALSE; | |
51 | ResetEvent(latch->wevent); | |
52 | return is_set; | |
53 | } | |
54 | ||
55 | /* Sets 'latch'. | |
56 | * | |
57 | * Calls are not additive: a single latch_poll() clears out any number of | |
58 | * latch_set(). */ | |
59 | void | |
60 | latch_set(struct latch *latch) | |
61 | { | |
62 | latch->is_set = TRUE; | |
63 | SetEvent(latch->wevent); | |
64 | } | |
65 | ||
66 | /* Returns true if 'latch' is set, false otherwise. Does not reset 'latch' | |
67 | * to the unset state. */ | |
68 | bool | |
69 | latch_is_set(const struct latch *latch) | |
70 | { | |
71 | return latch->is_set; | |
72 | } | |
73 | ||
74 | /* Causes the next poll_block() to wake up when 'latch' is set. | |
75 | * | |
76 | * ('where' is used in debug logging. Commonly one would use latch_wait() to | |
77 | * automatically provide the caller's source file and line number for | |
78 | * 'where'.) */ | |
79 | void | |
80 | latch_wait_at(const struct latch *latch, const char *where) | |
81 | { | |
1ca3348e | 82 | poll_wevent_wait_at(latch->wevent, where); |
4ca828d7 | 83 | } |