// Copyright GoFrame Author(https://goframe.org). All Rights Reserved.
//
// This Source Code Form is subject to the terms of the MIT License.
// If a copy of the MIT was not distributed with this file,
// You can obtain one at https://github.com/gogf/gf.

// Package rwmutex provides switch of concurrent safety feature for sync.RWMutex.
package rwmutex

import (
	"sync"
)

// RWMutex is a sync.RWMutex with a switch for concurrent safe feature.
// If its attribute *sync.RWMutex is not nil, it means it's in concurrent safety usage.
// Its attribute *sync.RWMutex is nil in default, which makes this struct mush lightweight.
type RWMutex struct {
	// Underlying mutex.
	mutex *sync.RWMutex
}

// New creates and returns a new *RWMutex.
// The parameter `safe` is used to specify whether using this mutex in concurrent safety,
// which is false in default.
func New(safe ...bool) *RWMutex {
	mu := Create(safe...)
	return &mu
}

// Create creates and returns a new RWMutex object.
// The parameter `safe` is used to specify whether using this mutex in concurrent safety,
// which is false in default.
func Create(safe ...bool) RWMutex {
	if len(safe) > 0 && safe[0] {
		return RWMutex{
			mutex: new(sync.RWMutex),
		}
	}
	return RWMutex{}
}

// IsSafe checks and returns whether current mutex is in concurrent-safe usage.
func (mu *RWMutex) IsSafe() bool {
	return mu.mutex != nil
}

// Lock locks mutex for writing.
// It does nothing if it is not in concurrent-safe usage.
func (mu *RWMutex) Lock() {
	if mu.mutex != nil {
		mu.mutex.Lock()
	}
}

// Unlock unlocks mutex for writing.
// It does nothing if it is not in concurrent-safe usage.
func (mu *RWMutex) Unlock() {
	if mu.mutex != nil {
		mu.mutex.Unlock()
	}
}

// RLock locks mutex for reading.
// It does nothing if it is not in concurrent-safe usage.
func (mu *RWMutex) RLock() {
	if mu.mutex != nil {
		mu.mutex.RLock()
	}
}

// RUnlock unlocks mutex for reading.
// It does nothing if it is not in concurrent-safe usage.
func (mu *RWMutex) RUnlock() {
	if mu.mutex != nil {
		mu.mutex.RUnlock()
	}
}