89 lines
2.9 KiB
Go
89 lines
2.9 KiB
Go
package core
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const minNLen = 16
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// TransactionGroup 事务分组
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type TransactionGroup struct {
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N int //总共分了多少个组
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Group [][][2]string //分组的结果
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Rely map[string]int //存储依赖关系
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}
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// NewGroup 新建分组
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func NewGroup() *TransactionGroup {
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//每个元素都是一个包含两个字符串的数组切片
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buf1 := make([][][2]string, minNLen)
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buf2 := make(map[string]int)
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return &TransactionGroup{
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N: 1,
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Group: buf1,
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Rely: buf2,
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}
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}
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// resizeGroup 对分组大小进行扩容
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// 切片 g.Group 扩展为原始长度的两倍，并将原始切片的内容复制到新创建的切片中
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func (g *TransactionGroup) resizeGroup() {
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newBuf := make([][][2]string, g.N<<1)
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copy(newBuf, g.Group[:])
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g.Group = newBuf
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}
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func (g *TransactionGroup) GroupTransactionsByDeps(table [][2]string) {
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for _, t := range table {
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g.AddEdge(t[0], t[1])
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}
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}
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// AddEdge 新加分组，t1、t2是存在依赖关系的两个事务
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func (g *TransactionGroup) AddEdge(t1, t2 string) {
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// 新元素入队之前，当队列长度等于缓存区长度时，缓存区长度重设为两个队列长度
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if g.N >= len(g.Group)*8/10 {
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g.resizeGroup()
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}
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//当事务t1和事务t2都没进行分组时，将t1和t2加入到一个新的分组中
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if g.Rely[t1] == 0 && g.Rely[t2] == 0 {
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g.Rely[t1], g.Rely[t2] = g.N, g.N
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g.Group[g.N] = append(g.Group[g.N], [2]string{t1, t2})
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g.N++
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} else if g.Rely[t1] > 0 && g.Rely[t2] == 0 { //如果t1已经分组，但是t2还没分组，则将t2加入到t1分组
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g.Rely[t2] = g.Rely[t1]
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g.Group[g.Rely[t1]] = append(g.Group[g.Rely[t1]], [2]string{t1, t2})
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} else if g.Rely[t1] == 0 && g.Rely[t2] > 0 { //如果t2已经分组，但是t1还没分组，则将t1加入到t2分组
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g.Rely[t1] = g.Rely[t2]
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g.Group[g.Rely[t2]] = append(g.Group[g.Rely[t2]], [2]string{t1, t2})
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} else if g.Rely[t1] == g.Rely[t2] { //事务t1和t2都已经分组,并且分到了同一个组中
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g.Group[g.Rely[t1]] = append(g.Group[g.Rely[t1]], [2]string{t1, t2})
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} else { //事务t1和t2都已经分组，但是分到了不同的组中
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//记录t2的分组
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temp := g.Rely[t2]
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//将t2组中的事务和t1组中的事务合并
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g.Group[g.Rely[t1]] = append(g.Group[g.Rely[t1]], g.Group[g.Rely[t2]]...)
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g.Group[g.Rely[t1]] = append(g.Group[g.Rely[t1]], [2]string{t1, t2})
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//将t2的分组改为t1的分组
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for _, txs := range g.Group[temp] {
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for _, tx := range txs {
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g.Rely[tx] = g.Rely[t1]
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}
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}
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g.Group[temp] = nil
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}
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}
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func DeepCopyGroup(group *TransactionGroup) *TransactionGroup {
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buf := make([][][2]string, len(group.Group))
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for i, arr := range group.Group {
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buf[i] = make([][2]string, len(arr))
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for j, subArr := range arr {
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buf[i][j] = [2]string{subArr[0], subArr[1]}
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}
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}
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copyMap := make(map[string]int)
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for key, value := range group.Rely {
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copyMap[key] = value
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}
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return &TransactionGroup{N: group.N, Group: buf, Rely: copyMap}
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}
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