github.com/mysteriumnetwork/node@v0.0.0-20240516044423-365054f76801/utils/actionstack/actionstack.go (about)

     1  /*
     2   * Copyright (C) 2021 The "MysteriumNetwork/node" Authors.
     3   *
     4   * This program is free software: you can redistribute it and/or modify
     5   * it under the terms of the GNU General Public License as published by
     6   * the Free Software Foundation, either version 3 of the License, or
     7   * (at your option) any later version.
     8   *
     9   * This program is distributed in the hope that it will be useful,
    10   * but WITHOUT ANY WARRANTY; without even the implied warranty of
    11   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    12   * GNU General Public License for more details.
    13   *
    14   * You should have received a copy of the GNU General Public License
    15   * along with this program.  If not, see <http://www.gnu.org/licenses/>.
    16   */
    17  
    18  package actionstack
    19  
    20  import (
    21  	"errors"
    22  	"sync"
    23  )
    24  
    25  var (
    26  	// ErrAlreadyRun error is throwed with panic on Push or Run invocation
    27  	// after Run was invoked at least once
    28  	ErrAlreadyRun = errors.New("actions already fired")
    29  )
    30  
    31  // Action represents stackable action.
    32  type Action func()
    33  
    34  // ActionStack is a stack of actions which are executed in reverse order
    35  // they were added
    36  type ActionStack struct {
    37  	stack []Action
    38  	fired bool
    39  	mu    sync.Mutex
    40  }
    41  
    42  // NewActionStack creates empty ActionStack
    43  func NewActionStack() *ActionStack {
    44  	return new(ActionStack)
    45  }
    46  
    47  // Run executes pushed actions in reverse order (FILO)
    48  func (a *ActionStack) Run() {
    49  	a.mu.Lock()
    50  	defer a.mu.Unlock()
    51  
    52  	if a.fired {
    53  		panic(ErrAlreadyRun)
    54  	}
    55  
    56  	for i := len(a.stack) - 1; i >= 0; i-- {
    57  		a.stack[i]()
    58  	}
    59  	a.stack = nil
    60  	a.fired = true
    61  }
    62  
    63  // Push adds new action on top of stack. Last added action will be executed
    64  // by Run() first.
    65  func (a *ActionStack) Push(elems ...Action) {
    66  	a.mu.Lock()
    67  	defer a.mu.Unlock()
    68  
    69  	if a.fired {
    70  		panic(ErrAlreadyRun)
    71  	}
    72  
    73  	a.stack = append(a.stack, elems...)
    74  }