| // Copyright (C) 2015 The Android Open Source Project |
| // |
| // Licensed under the Apache License, Version 2.0 (the "License"); |
| // you may not use this file except in compliance with the License. |
| // You may obtain a copy of the License at |
| // |
| // http://www.apache.org/licenses/LICENSE-2.0 |
| // |
| // Unless required by applicable law or agreed to in writing, software |
| // distributed under the License is distributed on an "AS IS" BASIS, |
| // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| // See the License for the specific language governing permissions and |
| // limitations under the License. |
| |
| package maker |
| |
| import ( |
| "sort" |
| "sync" |
| ) |
| |
| type lock struct { |
| name string |
| mu sync.Mutex |
| } |
| |
| var locks = map[string]*lock{} |
| |
| func addLock(name string) { |
| _, ok := locks[name] |
| if !ok { |
| locks[name] = &lock{name: name} |
| } |
| } |
| |
| func withLocks(accesses []string, do func()) { |
| // sort the names for consistent aquire order |
| sort.Strings(accesses) |
| // aquire all the mutexes in order |
| for _, name := range accesses { |
| locks[name].mu.Lock() |
| } |
| do() |
| // unlock order does not matter |
| for _, name := range accesses { |
| locks[name].mu.Unlock() |
| } |
| } |