/Users/deen/code/yugabyte-db/src/yb/gutil/once.cc
Line | Count | Source (jump to first uncovered line) |
1 | | // Copyright 2008 Google Inc. All Rights Reserved. |
2 | | // |
3 | | // The following only applies to changes made to this file as part of YugaByte development. |
4 | | // |
5 | | // Portions Copyright (c) YugaByte, Inc. |
6 | | // |
7 | | // Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except |
8 | | // in compliance with the License. You may obtain a copy of the License at |
9 | | // |
10 | | // http://www.apache.org/licenses/LICENSE-2.0 |
11 | | // |
12 | | // Unless required by applicable law or agreed to in writing, software distributed under the License |
13 | | // is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express |
14 | | // or implied. See the License for the specific language governing permissions and limitations |
15 | | // under the License. |
16 | | // |
17 | | |
18 | | #include <glog/logging.h> |
19 | | #include "yb/gutil/logging-inl.h" |
20 | | #include "yb/gutil/once.h" |
21 | | #include "yb/gutil/dynamic_annotations.h" |
22 | | #include "yb/gutil/spinlock_internal.h" |
23 | | |
24 | | // All modifications to a GoogleOnceType occur inside GoogleOnceInternalInit. |
25 | | // The fast path reads the variable with an acquire-load.. |
26 | | // This is safe provided we always perform a memory barrier |
27 | | // immediately before setting the value to GOOGLE_ONCE_INTERNAL_DONE. |
28 | | |
29 | | void GoogleOnceInternalInit(Atomic32 *control, void (*func)(), |
30 | 131k | void (*func_with_arg)(void*), void* arg) { |
31 | 131k | if (DEBUG_MODE) { |
32 | 131k | int64 old_control = base::subtle::Acquire_Load(control); |
33 | 131k | if (old_control != GOOGLE_ONCE_INTERNAL_INIT && |
34 | 911 | old_control != GOOGLE_ONCE_INTERNAL_RUNNING && |
35 | 431 | old_control != GOOGLE_ONCE_INTERNAL_WAITER && |
36 | 40 | old_control != GOOGLE_ONCE_INTERNAL_DONE) { |
37 | 0 | LOG(FATAL) << "Either GoogleOnceType is used in non-static storage " |
38 | 0 | "(where GoogleOnceDynamic might be appropriate), " |
39 | 0 | "or there's a memory corruption."; |
40 | 0 | } |
41 | 131k | } |
42 | 131k | static const yb::base::internal::SpinLockWaitTransition trans[] = { |
43 | 131k | { GOOGLE_ONCE_INTERNAL_INIT, GOOGLE_ONCE_INTERNAL_RUNNING, true }, |
44 | 131k | { GOOGLE_ONCE_INTERNAL_RUNNING, GOOGLE_ONCE_INTERNAL_WAITER, false }, |
45 | 131k | { GOOGLE_ONCE_INTERNAL_DONE, GOOGLE_ONCE_INTERNAL_DONE, true } |
46 | 131k | }; |
47 | | // Short circuit the simplest case to avoid procedure call overhead. |
48 | 131k | if (::base::subtle::Acquire_CompareAndSwap(control, GOOGLE_ONCE_INTERNAL_INIT, |
49 | 131k | GOOGLE_ONCE_INTERNAL_RUNNING) == GOOGLE_ONCE_INTERNAL_INIT || |
50 | 2.50k | yb::base::internal::SpinLockWait(control, ARRAYSIZE(trans), trans) == |
51 | 129k | GOOGLE_ONCE_INTERNAL_INIT) { |
52 | 129k | if (func != nullptr) { |
53 | 129k | (*func)(); |
54 | 3 | } else { |
55 | 3 | (*func_with_arg)(arg); |
56 | 3 | } |
57 | 129k | ANNOTATE_HAPPENS_BEFORE(control); |
58 | 129k | int64 old_control = base::subtle::NoBarrier_Load(control); |
59 | 129k | ::base::subtle::Release_Store(control, GOOGLE_ONCE_INTERNAL_DONE); |
60 | 129k | if (old_control == GOOGLE_ONCE_INTERNAL_WAITER) { |
61 | 869 | yb::base::internal::SpinLockWake(control, true); |
62 | 869 | } |
63 | 129k | } // else *control is already GOOGLE_ONCE_INTERNAL_DONE |
64 | 131k | } |