gf/g/container/gmap/gmap_link_map.go

// Copyright 2017 gf Author(https://github.com/gogf/gf). 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 gm file,
// You can obtain one at https://github.com/gogf/gf.

package gmap

import (
	"github.com/gogf/gf/g/container/glist"
	"github.com/gogf/gf/g/container/gvar"
	"github.com/gogf/gf/g/internal/rwmutex"
)

type LinkMap struct {
    mu   *rwmutex.RWMutex
    data map[interface{}]*glist.Element
    list *glist.List
}

type gLinkMapNode struct {
	key     interface{}
	value   interface{}
}

// NewLinkMap returns an empty link map.
// LinkMap is backed by a hash table to store values and doubly-linked list to store ordering.
// The param <unsafe> used to specify whether using map in un-concurrent-safety,
// which is false in default, means concurrent-safe.
func NewLinkMap(unsafe ...bool) *LinkMap {
	return &LinkMap{
		mu   : rwmutex.New(unsafe...),
		data : make(map[interface{}]*glist.Element),
		list : glist.New(true),
	}
}

// NewLinkMapFrom returns a link map from given map <data>.
// Note that, the param <data> map will be set as the underlying data map(no deep copy),
// there might be some concurrent-safe issues when changing the map outside.
func NewLinkMapFrom(data map[interface{}]interface{}, unsafe...bool) *LinkMap {
    m := NewLinkMap(unsafe...)
    m.Sets(data)
    return m
}

// Iterator is alias of IteratorAsc.
func (m *LinkMap) Iterator(f func (key, value interface{}) bool) {
	m.IteratorAsc(f)
}

// IteratorAsc iterates the map in ascending order with given callback function <f>.
// If <f> returns true, then it continues iterating; or false to stop.
func (m *LinkMap) IteratorAsc(f func (key interface{}, value interface{}) bool) {
    m.mu.RLock()
    defer m.mu.RUnlock()
    node := (*gLinkMapNode)(nil)
    m.list.IteratorAsc(func(e *glist.Element) bool {
    	node = e.Value.(*gLinkMapNode)
	    return f(node.key, node.value)
    })
}

// IteratorDesc iterates the map in descending order with given callback function <f>.
// If <f> returns true, then it continues iterating; or false to stop.
func (m *LinkMap) IteratorDesc(f func (key interface{}, value interface{}) bool) {
	m.mu.RLock()
	defer m.mu.RUnlock()
	node := (*gLinkMapNode)(nil)
	m.list.IteratorDesc(func(e *glist.Element) bool {
		node = e.Value.(*gLinkMapNode)
		return f(node.key, node.value)
	})
}

// Clone returns a new link map with copy of current map data.
func (m *LinkMap) Clone(unsafe ...bool) *LinkMap {
   return NewLinkMapFrom(m.Map(), unsafe ...)
}

// Clear deletes all data of the map, it will remake a new underlying data map.
func (m *LinkMap) Clear() {
	m.mu.Lock()
	m.data = make(map[interface{}]*glist.Element)
	m.list = glist.New(true)
	m.mu.Unlock()
}

// Map returns a copy of the data of the map.
func (m *LinkMap) Map() map[interface{}]interface{} {
    m.mu.RLock()
	node := (*gLinkMapNode)(nil)
	data := make(map[interface{}]interface{}, len(m.data))
	m.list.IteratorAsc(func(e *glist.Element) bool {
		node = e.Value.(*gLinkMapNode)
		data[node.key] = node.value
		return true
	})
    m.mu.RUnlock()
    return data
}

// Set sets key-value to the map.
func (m *LinkMap) Set(key interface{}, value interface{}) {
    m.mu.Lock()
    if e, ok := m.data[key]; !ok {
	    m.data[key] = m.list.PushBack(&gLinkMapNode{key, value})
    } else {
    	e.Value     = &gLinkMapNode{key, value}
    }
    m.mu.Unlock()
}

// Sets batch sets key-values to the map.
func (m *LinkMap) Sets(data map[interface{}]interface{}) {
    m.mu.Lock()
    for key, value := range data {
	    if e, ok := m.data[key]; !ok {
		    m.data[key] = m.list.PushBack(&gLinkMapNode{key, value})
	    } else {
		    e.Value     = &gLinkMapNode{key, value}
	    }
    }
    m.mu.Unlock()
}

// Search searches the map with given <key>.
// Second return parameter <found> is true if key was found, otherwise false.
func (m *LinkMap) Search(key interface{}) (value interface{}, found bool) {
	m.mu.RLock()
	if e, ok := m.data[key]; ok {
		value = e.Value.(*gLinkMapNode).value
		found = ok
	}
	m.mu.RUnlock()
	return
}

// Get returns the value by given <key>.
func (m *LinkMap) Get(key interface{}) (value interface{}) {
    m.mu.RLock()
    if e, ok := m.data[key]; ok {
    	value = e.Value.(*gLinkMapNode).value
    }
    m.mu.RUnlock()
    return
}

// doSetWithLockCheck checks whether value of the key exists with mutex.Lock,
// if not exists, set value to the map with given <key>,
// or else just return the existing value.
//
// When setting value, if <value> is type of <func() interface {}>,
// it will be executed with mutex.Lock of the map,
// and its return value will be set to the map with <key>.
//
// It returns value with given <key>.
func (m *LinkMap) doSetWithLockCheck(key interface{}, value interface{}) interface{} {
    m.mu.Lock()
    defer m.mu.Unlock()
    if e, ok := m.data[key]; ok {
        return e.Value.(*gLinkMapNode).value
    }
    if f, ok := value.(func() interface {}); ok {
        value = f()
    }
    m.data[key] = m.list.PushBack(&gLinkMapNode{key, value})
    return value
}

// GetOrSet returns the value by key,
// or set value with given <value> if not exist and returns this value.
func (m *LinkMap) GetOrSet(key interface{}, value interface{}) interface{} {
	if v, ok := m.Search(key); !ok {
        return m.doSetWithLockCheck(key, value)
    } else {
        return v
    }
}

// GetOrSetFunc returns the value by key,
// or sets value with return value of callback function <f> if not exist
// and returns this value.
func (m *LinkMap) GetOrSetFunc(key interface{}, f func() interface{}) interface{} {
	if v, ok := m.Search(key); !ok {
        return m.doSetWithLockCheck(key, f())
    } else {
        return v
    }
}

// GetOrSetFuncLock returns the value by key,
// or sets value with return value of callback function <f> if not exist
// and returns this value.
//
// GetOrSetFuncLock differs with GetOrSetFunc function is that it executes function <f>
// with mutex.Lock of the map.
func (m *LinkMap) GetOrSetFuncLock(key interface{}, f func() interface{}) interface{} {
	if v, ok := m.Search(key); !ok {
        return m.doSetWithLockCheck(key, f)
    } else {
        return v
    }
}

// GetVar returns a gvar.Var with the value by given <key>.
// The returned gvar.Var is un-concurrent safe.
func (m *LinkMap) GetVar(key interface{}) *gvar.Var {
	return gvar.New(m.Get(key), true)
}

// GetVarOrSet returns a gvar.Var with result from GetVarOrSet.
// The returned gvar.Var is un-concurrent safe.
func (m *LinkMap) GetVarOrSet(key interface{}, value interface{}) *gvar.Var {
	return gvar.New(m.GetOrSet(key, value), true)
}

// GetVarOrSetFunc returns a gvar.Var with result from GetOrSetFunc.
// The returned gvar.Var is un-concurrent safe.
func (m *LinkMap) GetVarOrSetFunc(key interface{}, f func() interface{}) *gvar.Var {
	return gvar.New(m.GetOrSetFunc(key, f), true)
}

// GetVarOrSetFuncLock returns a gvar.Var with result from GetOrSetFuncLock.
// The returned gvar.Var is un-concurrent safe.
func (m *LinkMap) GetVarOrSetFuncLock(key interface{}, f func() interface{}) *gvar.Var {
	return gvar.New(m.GetOrSetFuncLock(key, f), true)
}

// SetIfNotExist sets <value> to the map if the <key> does not exist, then return true.
// It returns false if <key> exists, and <value> would be ignored.
func (m *LinkMap) SetIfNotExist(key interface{}, value interface{}) bool {
    if !m.Contains(key) {
        m.doSetWithLockCheck(key, value)
        return true
    }
    return false
}

// SetIfNotExistFunc sets value with return value of callback function <f>, then return true.
// It returns false if <key> exists, and <value> would be ignored.
func (m *LinkMap) SetIfNotExistFunc(key interface{}, f func() interface{}) bool {
	if !m.Contains(key) {
		m.doSetWithLockCheck(key, f())
		return true
	}
	return false
}

// SetIfNotExistFuncLock sets value with return value of callback function <f>, then return true.
// It returns false if <key> exists, and <value> would be ignored.
//
// SetIfNotExistFuncLock differs with SetIfNotExistFunc function is that
// it executes function <f> with mutex.Lock of the map.
func (m *LinkMap) SetIfNotExistFuncLock(key interface{}, f func() interface{}) bool {
	if !m.Contains(key) {
		m.doSetWithLockCheck(key, f)
		return true
	}
	return false
}

// Remove deletes value from map by given <key>, and return this deleted value.
func (m *LinkMap) Remove(key interface{}) (value interface{}) {
    m.mu.Lock()
    if e, ok := m.data[key]; ok {
    	value = e.Value.(*gLinkMapNode).value
        delete(m.data, key)
        m.list.Remove(e)
    }
    m.mu.Unlock()
    return
}

// Removes batch deletes values of the map by keys.
func (m *LinkMap) Removes(keys []interface{}) {
	m.mu.Lock()
	for _, key := range keys {
		if e, ok := m.data[key]; ok {
			delete(m.data, key)
			m.list.Remove(e)
		}
	}
	m.mu.Unlock()
}

// Keys returns all keys of the map as a slice in ascending order.
func (m *LinkMap) Keys() []interface{} {
    m.mu.RLock()
    keys  := make([]interface{}, m.list.Len())
    index := 0
    m.list.IteratorAsc(func(e *glist.Element) bool {
	    keys[index] = e.Value.(*gLinkMapNode).key
	    index++
	    return true
    })
    m.mu.RUnlock()
    return keys
}

// Values returns all values of the map as a slice.
func (m *LinkMap) Values() []interface{} {
    m.mu.RLock()
    values := make([]interface{}, m.list.Len())
	index  := 0
	m.list.IteratorAsc(func(e *glist.Element) bool {
		values[index] = e.Value.(*gLinkMapNode).value
		index++
		return true
	})
    m.mu.RUnlock()
    return values
}

// Contains checks whether a key exists.
// It returns true if the <key> exists, or else false.
func (m *LinkMap) Contains(key interface{}) (ok bool) {
    m.mu.RLock()
    _, ok = m.data[key]
    m.mu.RUnlock()
    return
}

// Size returns the size of the map.
func (m *LinkMap) Size() (size int) {
    m.mu.RLock()
    size = len(m.data)
    m.mu.RUnlock()
    return
}

// IsEmpty checks whether the map is empty.
// It returns true if map is empty, or else false.
func (m *LinkMap) IsEmpty() bool {
    return m.Size() == 0
}

// Flip exchanges key-value of the map to value-key.
func (m *LinkMap) Flip() {
    data := m.Map()
    m.Clear()
    for key, value := range data {
    	m.Set(value, key)
    }
}

// Merge merges two link maps.
// The <other> map will be merged into the map <m>.
func (m *LinkMap) Merge(other *LinkMap) {
    m.mu.Lock()
    defer m.mu.Unlock()
    if other != m {
	    other.mu.RLock()
        defer other.mu.RUnlock()
    }
	node := (*gLinkMapNode)(nil)
    other.list.IteratorAsc(func(e *glist.Element) bool {
	    node = e.Value.(*gLinkMapNode)
	    if e, ok := m.data[node.key]; !ok {
		    m.data[node.key] = m.list.PushBack(&gLinkMapNode{node.key, node.value})
	    } else {
		    e.Value = &gLinkMapNode{node.key, node.value}
	    }
	    return true
    })
}