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 #ifndef GRPC_CORE_LIB_IOMGR_CLOSURE_H
20 #define GRPC_CORE_LIB_IOMGR_CLOSURE_H
21
22 #include <grpc/support/port_platform.h>
23
24 #include <assert.h>
25 #include <stdbool.h>
26
27 #include <grpc/support/alloc.h>
28 #include <grpc/support/log.h>
29
30 #include "src/core/lib/gprpp/debug_location.h"
31 #include "src/core/lib/gprpp/manual_constructor.h"
32 #include "src/core/lib/gprpp/mpscq.h"
33 #include "src/core/lib/iomgr/error.h"
34 #include "src/core/lib/profiling/timers.h"
35
36 struct grpc_closure;
37 typedef struct grpc_closure grpc_closure;
38
39 extern grpc_core::DebugOnlyTraceFlag grpc_trace_closure;
40
41 typedef struct grpc_closure_list {
42 grpc_closure* head;
43 grpc_closure* tail;
44 } grpc_closure_list;
45
46 /** gRPC Callback definition.
47 *
48 * \param arg Arbitrary input.
49 * \param error GRPC_ERROR_NONE if no error occurred, otherwise some grpc_error
50 * describing what went wrong.
51 * Error contract: it is not the cb's job to unref this error;
52 * the closure scheduler will do that after the cb returns */
53 typedef void (*grpc_iomgr_cb_func)(void* arg, grpc_error_handle error);
54
55 /** A closure over a grpc_iomgr_cb_func. */
56 struct grpc_closure {
57 /** Once queued, next indicates the next queued closure; before then, scratch
58 * space */
59 union {
60 grpc_closure* next;
61 grpc_core::ManualConstructor<
62 grpc_core::MultiProducerSingleConsumerQueue::Node>
63 mpscq_node;
64 uintptr_t scratch;
65 } next_data;
66
67 /** Bound callback. */
68 grpc_iomgr_cb_func cb;
69
70 /** Arguments to be passed to "cb". */
71 void* cb_arg;
72
73 /** Once queued, the result of the closure. Before then: scratch space */
74 union {
75 grpc_error_handle error;
76 uintptr_t scratch;
77 } error_data;
78
79 // extra tracing and debugging for grpc_closure. This incurs a decent amount of
80 // overhead per closure, so it must be enabled at compile time.
81 #ifndef NDEBUG
82 bool scheduled;
83 bool run; // true = run, false = scheduled
84 const char* file_created;
85 int line_created;
86 const char* file_initiated;
87 int line_initiated;
88 #endif
89 };
90
91 #ifndef NDEBUG
grpc_closure_init(const char * file,int line,grpc_closure * closure,grpc_iomgr_cb_func cb,void * cb_arg)92 inline grpc_closure* grpc_closure_init(const char* file, int line,
93 grpc_closure* closure,
94 grpc_iomgr_cb_func cb, void* cb_arg) {
95 #else
96 inline grpc_closure* grpc_closure_init(grpc_closure* closure,
97 grpc_iomgr_cb_func cb, void* cb_arg) {
98 #endif
99 closure->cb = cb;
100 closure->cb_arg = cb_arg;
101 closure->error_data.error = GRPC_ERROR_NONE;
102 #ifndef NDEBUG
103 closure->scheduled = false;
104 closure->file_initiated = nullptr;
105 closure->line_initiated = 0;
106 closure->run = false;
107 closure->file_created = file;
108 closure->line_created = line;
109 #endif
110 return closure;
111 }
112
113 /** Initializes \a closure with \a cb and \a cb_arg. Returns \a closure. */
114 #ifndef NDEBUG
115 #define GRPC_CLOSURE_INIT(closure, cb, cb_arg, scheduler) \
116 grpc_closure_init(__FILE__, __LINE__, closure, cb, cb_arg)
117 #else
118 #define GRPC_CLOSURE_INIT(closure, cb, cb_arg, scheduler) \
119 grpc_closure_init(closure, cb, cb_arg)
120 #endif
121
122 namespace closure_impl {
123
124 struct wrapped_closure {
125 grpc_iomgr_cb_func cb;
126 void* cb_arg;
127 grpc_closure wrapper;
128 };
129 inline void closure_wrapper(void* arg, grpc_error_handle error) {
130 wrapped_closure* wc = static_cast<wrapped_closure*>(arg);
131 grpc_iomgr_cb_func cb = wc->cb;
132 void* cb_arg = wc->cb_arg;
133 gpr_free(wc);
134 cb(cb_arg, error);
135 }
136
137 } // namespace closure_impl
138
139 #ifndef NDEBUG
140 inline grpc_closure* grpc_closure_create(const char* file, int line,
141 grpc_iomgr_cb_func cb, void* cb_arg) {
142 #else
143 inline grpc_closure* grpc_closure_create(grpc_iomgr_cb_func cb, void* cb_arg) {
144 #endif
145 closure_impl::wrapped_closure* wc =
146 static_cast<closure_impl::wrapped_closure*>(gpr_malloc(sizeof(*wc)));
147 wc->cb = cb;
148 wc->cb_arg = cb_arg;
149 #ifndef NDEBUG
150 grpc_closure_init(file, line, &wc->wrapper, closure_impl::closure_wrapper,
151 wc);
152 #else
153 grpc_closure_init(&wc->wrapper, closure_impl::closure_wrapper, wc);
154 #endif
155 return &wc->wrapper;
156 }
157
158 /* Create a heap allocated closure: try to avoid except for very rare events */
159 #ifndef NDEBUG
160 #define GRPC_CLOSURE_CREATE(cb, cb_arg, scheduler) \
161 grpc_closure_create(__FILE__, __LINE__, cb, cb_arg)
162 #else
163 #define GRPC_CLOSURE_CREATE(cb, cb_arg, scheduler) \
164 grpc_closure_create(cb, cb_arg)
165 #endif
166
167 #define GRPC_CLOSURE_LIST_INIT \
168 { nullptr, nullptr }
169
170 inline void grpc_closure_list_init(grpc_closure_list* closure_list) {
171 closure_list->head = closure_list->tail = nullptr;
172 }
173
174 /** add \a closure to the end of \a list
175 and set \a closure's result to \a error
176 Returns true if \a list becomes non-empty */
177 inline bool grpc_closure_list_append(grpc_closure_list* closure_list,
178 grpc_closure* closure,
179 grpc_error_handle error) {
180 if (closure == nullptr) {
181 GRPC_ERROR_UNREF(error);
182 return false;
183 }
184 closure->error_data.error = error;
185 closure->next_data.next = nullptr;
186 bool was_empty = (closure_list->head == nullptr);
187 if (was_empty) {
188 closure_list->head = closure;
189 } else {
190 closure_list->tail->next_data.next = closure;
191 }
192 closure_list->tail = closure;
193 return was_empty;
194 }
195
196 /** force all success bits in \a list to false */
197 inline void grpc_closure_list_fail_all(grpc_closure_list* list,
198 grpc_error_handle forced_failure) {
199 for (grpc_closure* c = list->head; c != nullptr; c = c->next_data.next) {
200 if (c->error_data.error == GRPC_ERROR_NONE) {
201 c->error_data.error = GRPC_ERROR_REF(forced_failure);
202 }
203 }
204 GRPC_ERROR_UNREF(forced_failure);
205 }
206
207 /** append all closures from \a src to \a dst and empty \a src. */
208 inline void grpc_closure_list_move(grpc_closure_list* src,
209 grpc_closure_list* dst) {
210 if (src->head == nullptr) {
211 return;
212 }
213 if (dst->head == nullptr) {
214 *dst = *src;
215 } else {
216 dst->tail->next_data.next = src->head;
217 dst->tail = src->tail;
218 }
219 src->head = src->tail = nullptr;
220 }
221
222 /** return whether \a list is empty. */
223 inline bool grpc_closure_list_empty(grpc_closure_list closure_list) {
224 return closure_list.head == nullptr;
225 }
226
227 namespace grpc_core {
228 class Closure {
229 public:
230 static void Run(const DebugLocation& location, grpc_closure* closure,
231 grpc_error_handle error) {
232 (void)location;
233 if (closure == nullptr) {
234 GRPC_ERROR_UNREF(error);
235 return;
236 }
237 #ifndef NDEBUG
238 if (grpc_trace_closure.enabled()) {
239 gpr_log(GPR_DEBUG, "running closure %p: created [%s:%d]: run [%s:%d]",
240 closure, closure->file_created, closure->line_created,
241 location.file(), location.line());
242 }
243 GPR_ASSERT(closure->cb != nullptr);
244 #endif
245 closure->cb(closure->cb_arg, error);
246 #ifndef NDEBUG
247 if (grpc_trace_closure.enabled()) {
248 gpr_log(GPR_DEBUG, "closure %p finished", closure);
249 }
250 #endif
251 GRPC_ERROR_UNREF(error);
252 }
253 };
254 } // namespace grpc_core
255
256 #endif /* GRPC_CORE_LIB_IOMGR_CLOSURE_H */
257