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1 //
2 //
3 // Copyright 2015 gRPC authors.
4 //
5 // Licensed under the Apache License, Version 2.0 (the "License");
6 // you may not use this file except in compliance with the License.
7 // You may obtain a copy of the License at
8 //
9 //     http://www.apache.org/licenses/LICENSE-2.0
10 //
11 // Unless required by applicable law or agreed to in writing, software
12 // distributed under the License is distributed on an "AS IS" BASIS,
13 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 // See the License for the specific language governing permissions and
15 // limitations under the License.
16 //
17 //
18 
19 // Win32 code for gpr synchronization support.
20 
21 #include <grpc/support/port_platform.h>
22 
23 #if defined(GPR_WINDOWS) && !defined(GPR_ABSEIL_SYNC) && \
24     !defined(GPR_CUSTOM_SYNC)
25 
26 #include <grpc/support/log.h>
27 #include <grpc/support/sync.h>
28 #include <grpc/support/time.h>
29 
30 #include "src/core/lib/gprpp/crash.h"
31 
gpr_mu_init(gpr_mu * mu)32 void gpr_mu_init(gpr_mu* mu) {
33   InitializeCriticalSection(&mu->cs);
34   mu->locked = 0;
35 }
36 
gpr_mu_destroy(gpr_mu * mu)37 void gpr_mu_destroy(gpr_mu* mu) { DeleteCriticalSection(&mu->cs); }
38 
gpr_mu_lock(gpr_mu * mu)39 void gpr_mu_lock(gpr_mu* mu) {
40   EnterCriticalSection(&mu->cs);
41   GPR_ASSERT(!mu->locked);
42   mu->locked = 1;
43 }
44 
gpr_mu_unlock(gpr_mu * mu)45 void gpr_mu_unlock(gpr_mu* mu) {
46   mu->locked = 0;
47   LeaveCriticalSection(&mu->cs);
48 }
49 
gpr_mu_trylock(gpr_mu * mu)50 int gpr_mu_trylock(gpr_mu* mu) {
51   int result = TryEnterCriticalSection(&mu->cs);
52   if (result) {
53     if (mu->locked) {                 // This thread already holds the lock.
54       LeaveCriticalSection(&mu->cs);  // Decrement lock count.
55       result = 0;                     // Indicate failure
56     }
57     mu->locked = 1;
58   }
59   return result;
60 }
61 
62 //----------------------------------------
63 
gpr_cv_init(gpr_cv * cv)64 void gpr_cv_init(gpr_cv* cv) { InitializeConditionVariable(cv); }
65 
gpr_cv_destroy(gpr_cv * cv)66 void gpr_cv_destroy(gpr_cv* cv) {
67   // Condition variables don't need destruction in Win32.
68 }
69 
gpr_cv_wait(gpr_cv * cv,gpr_mu * mu,gpr_timespec abs_deadline)70 int gpr_cv_wait(gpr_cv* cv, gpr_mu* mu, gpr_timespec abs_deadline) {
71   int timeout = 0;
72   DWORD timeout_max_ms;
73   mu->locked = 0;
74   if (gpr_time_cmp(abs_deadline, gpr_inf_future(abs_deadline.clock_type)) ==
75       0) {
76     SleepConditionVariableCS(cv, &mu->cs, INFINITE);
77   } else {
78     abs_deadline = gpr_convert_clock_type(abs_deadline, GPR_CLOCK_REALTIME);
79     gpr_timespec now = gpr_now(abs_deadline.clock_type);
80     int64_t now_ms = (int64_t)now.tv_sec * 1000 + now.tv_nsec / 1000000;
81     int64_t deadline_ms =
82         (int64_t)abs_deadline.tv_sec * 1000 + abs_deadline.tv_nsec / 1000000;
83     if (now_ms >= deadline_ms) {
84       timeout = 1;
85     } else {
86       if ((deadline_ms - now_ms) >= INFINITE) {
87         timeout_max_ms = INFINITE - 1;
88       } else {
89         timeout_max_ms = (DWORD)(deadline_ms - now_ms);
90       }
91       timeout = (SleepConditionVariableCS(cv, &mu->cs, timeout_max_ms) == 0 &&
92                  GetLastError() == ERROR_TIMEOUT);
93     }
94   }
95   mu->locked = 1;
96   return timeout;
97 }
98 
gpr_cv_signal(gpr_cv * cv)99 void gpr_cv_signal(gpr_cv* cv) { WakeConditionVariable(cv); }
100 
gpr_cv_broadcast(gpr_cv * cv)101 void gpr_cv_broadcast(gpr_cv* cv) { WakeAllConditionVariable(cv); }
102 
103 //----------------------------------------
104 
105 static void* phony;
106 struct run_once_func_arg {
107   void (*init_function)(void);
108 };
run_once_func(gpr_once * once,void * v,void ** pv)109 static BOOL CALLBACK run_once_func(gpr_once* once, void* v, void** pv) {
110   struct run_once_func_arg* arg = (struct run_once_func_arg*)v;
111   (*arg->init_function)();
112   return 1;
113 }
114 
gpr_once_init(gpr_once * once,void (* init_function)(void))115 void gpr_once_init(gpr_once* once, void (*init_function)(void)) {
116   struct run_once_func_arg arg;
117   arg.init_function = init_function;
118   InitOnceExecuteOnce(once, run_once_func, &arg, &phony);
119 }
120 
121 #endif  // defined(GPR_WINDOWS) && !defined(GPR_ABSEIL_SYNC) &&
122         // !defined(GPR_CUSTOM_SYNC)
123