vitess.io/vitess@v0.16.2/go/event/hooks.go (about)

     1  /*
     2  Copyright 2019 The Vitess Authors.
     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  package event
    18  
    19  import (
    20  	"sync"
    21  )
    22  
    23  // Hooks holds a list of parameter-less functions to call whenever the set is
    24  // triggered with Fire().
    25  type Hooks struct {
    26  	funcs []func()
    27  	mu    sync.Mutex
    28  }
    29  
    30  // Add appends the given function to the list to be triggered.
    31  func (h *Hooks) Add(f func()) {
    32  	h.mu.Lock()
    33  	defer h.mu.Unlock()
    34  	h.funcs = append(h.funcs, f)
    35  }
    36  
    37  // Fire calls all the functions in a given Hooks list. It launches a goroutine
    38  // for each function and then waits for all of them to finish before returning.
    39  // Concurrent calls to Fire() are serialized.
    40  func (h *Hooks) Fire() {
    41  	h.mu.Lock()
    42  	defer h.mu.Unlock()
    43  
    44  	wg := sync.WaitGroup{}
    45  
    46  	for _, f := range h.funcs {
    47  		wg.Add(1)
    48  		go func(f func()) {
    49  			f()
    50  			wg.Done()
    51  		}(f)
    52  	}
    53  	wg.Wait()
    54  }