【go源码分析】go源码之list源码分析

妖狐艹你老母 2022-04-18 05:05 462阅读 0赞

本文针对go 1.11版本，路径src/container/list/list.go

# 数据结构 #

### Element结构体 ###

*  Value
 *  前驱
 *  后继

// Element is an element of a linked list.
    type Element struct {
    	// Next and previous pointers in the doubly-linked list of elements.
    	// To simplify the implementation, internally a list l is implemented
    	// as a ring, such that &l.root is both the next element of the last
    	// list element (l.Back()) and the previous element of the first list
    	// element (l.Front()).
    	next, prev *Element
    
    	// The list to which this element belongs.
    	list *List
    
    	// The value stored with this element.
    	Value interface{}
    }

### List结构体 ###

双向列表，包括链表节点个数

// List represents a doubly linked list.
    // The zero value for List is an empty list ready to use.
    type List struct {
    	root Element // sentinel list element, only &root, root.prev, and root.next are used
    	len  int     // current list length excluding (this) sentinel element
    }

# 1. 双向链表初始化 #

节点个数为0，前驱后前继都指向root节点

// Init initializes or clears list l.
    func (l *List) Init() *List {
    	l.root.next = &l.root
    	l.root.prev = &l.root
    	l.len = 0
    	return l
    }
    
    // New returns an initialized list.
    func New() *List { return new(List).Init() }

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# 2. insert函数 #

代码简单明了，就是改变prev next指针，注意别指丢了就行

// insert inserts e after at, increments l.len, and returns e.
    func (l *List) insert(e, at *Element) *Element {
    	n := at.next
    	at.next = e
    	e.prev = at
    	e.next = n
    	n.prev = e
    	e.list = l
    	l.len++
    	return e
    }

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3pob25nbGluemhhbmc_size_16_color_FFFFFF_t_70 1][]

### 3. remove函数 ###

删除操作，避免内存泄露，等待gc回收

// remove removes e from its list, decrements l.len, and returns e.
    func (l *List) remove(e *Element) *Element {
    	e.prev.next = e.next
    	e.next.prev = e.prev
    	e.next = nil // avoid memory leaks
    	e.prev = nil // avoid memory leaks
    	e.list = nil
    	l.len--
    	return e
    }

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