307 lines
6.5 KiB
Go
307 lines
6.5 KiB
Go
package services
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// Edit 表示编辑操作类型
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type EditType int
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const (
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// EditInsert 插入操作
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EditInsert EditType = iota
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// EditDelete 删除操作
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EditDelete
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// EditEqual 相等部分
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EditEqual
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)
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// Edit 表示单个编辑操作
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type Edit struct {
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Type EditType // 操作类型
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Content string // 操作内容
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}
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// DiffResult 包含差异比较的结果信息
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type DiffResult struct {
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Edits []Edit // 编辑操作列表
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InsertCount int // 插入的字符数
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DeleteCount int // 删除的字符数
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ChangedLines int // 变更的行数
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TotalChanges int // 总变更字符数（插入+删除）
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ChangedTokens int // 变更的token数（如单词、标识符等）
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}
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// calculateChangesDetailed 使用Myers差分算法计算两个字符串之间的具体变更
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func calculateChangesDetailed(oldText, newText string) DiffResult {
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// 将文本分割成行
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oldLines := splitLines(oldText)
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newLines := splitLines(newText)
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// 计算行级别的差异
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edits := computeLineEdits(oldLines, newLines)
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// 计算变更统计
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result := DiffResult{
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Edits: edits,
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}
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// 统计变更
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for _, edit := range edits {
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switch edit.Type {
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case EditInsert:
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result.InsertCount += len(edit.Content)
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result.ChangedLines++
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case EditDelete:
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result.DeleteCount += len(edit.Content)
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result.ChangedLines++
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}
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}
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result.TotalChanges = result.InsertCount + result.DeleteCount
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result.ChangedTokens = estimateChangedTokens(edits)
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return result
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}
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// splitLines 将文本分割成行
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func splitLines(text string) []string {
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var lines []string
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var currentLine string
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for _, char := range text {
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if char == '\n' {
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lines = append(lines, currentLine)
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currentLine = ""
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} else {
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currentLine += string(char)
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}
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}
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// 添加最后一行（如果不是以换行符结尾）
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if currentLine != "" {
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lines = append(lines, currentLine)
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}
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return lines
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}
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// computeLineEdits 使用Myers差分算法计算行级别的差异
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func computeLineEdits(oldLines, newLines []string) []Edit {
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var edits []Edit
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// 使用Myers差分算法计算行级别的差异
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script := myersDiff(oldLines, newLines)
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// 将差异脚本转换为编辑操作
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for _, op := range script {
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switch op.Type {
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case EditEqual:
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edits = append(edits, Edit{
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Type: EditEqual,
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Content: oldLines[op.OldStart],
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})
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case EditDelete:
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edits = append(edits, Edit{
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Type: EditDelete,
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Content: oldLines[op.OldStart],
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})
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case EditInsert:
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edits = append(edits, Edit{
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Type: EditInsert,
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Content: newLines[op.NewStart],
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})
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}
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}
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return edits
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}
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// DiffOp 表示差分操作
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type DiffOp struct {
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Type EditType
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OldStart int
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OldEnd int
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NewStart int
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NewEnd int
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}
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// myersDiff 实现Myers差分算法
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func myersDiff(oldLines, newLines []string) []DiffOp {
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// 基本思路：Myers差分算法通过建立编辑图来寻找最短编辑路径
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// 简化版实现
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var script []DiffOp
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oldLen := len(oldLines)
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newLen := len(newLines)
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// 使用动态规划找出最长公共子序列(LCS)
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lcs := longestCommonSubsequence(oldLines, newLines)
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// 根据LCS构建差分脚本
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oldIndex, newIndex := 0, 0
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for _, entry := range lcs {
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// 处理LCS之前的差异
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for oldIndex < entry.OldIndex {
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script = append(script, DiffOp{
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Type: EditDelete,
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OldStart: oldIndex,
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OldEnd: oldIndex + 1,
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NewStart: newIndex,
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NewEnd: newIndex,
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})
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oldIndex++
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}
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for newIndex < entry.NewIndex {
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script = append(script, DiffOp{
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Type: EditInsert,
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OldStart: oldIndex,
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OldEnd: oldIndex,
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NewStart: newIndex,
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NewEnd: newIndex + 1,
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})
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newIndex++
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}
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// 处理相等部分
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script = append(script, DiffOp{
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Type: EditEqual,
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OldStart: oldIndex,
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OldEnd: oldIndex + 1,
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NewStart: newIndex,
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NewEnd: newIndex + 1,
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})
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oldIndex++
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newIndex++
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}
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// 处理剩余差异
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for oldIndex < oldLen {
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script = append(script, DiffOp{
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Type: EditDelete,
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OldStart: oldIndex,
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OldEnd: oldIndex + 1,
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NewStart: newIndex,
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NewEnd: newIndex,
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})
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oldIndex++
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}
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for newIndex < newLen {
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script = append(script, DiffOp{
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Type: EditInsert,
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OldStart: oldIndex,
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OldEnd: oldIndex,
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NewStart: newIndex,
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NewEnd: newIndex + 1,
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})
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newIndex++
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}
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return script
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}
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// LCSEntry 表示最长公共子序列中的一个条目
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type LCSEntry struct {
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OldIndex int
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NewIndex int
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}
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// longestCommonSubsequence 寻找两个字符串数组的最长公共子序列
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func longestCommonSubsequence(oldLines, newLines []string) []LCSEntry {
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oldLen := len(oldLines)
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newLen := len(newLines)
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// 创建动态规划表
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dp := make([][]int, oldLen+1)
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for i := range dp {
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dp[i] = make([]int, newLen+1)
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}
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// 填充DP表
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for i := 1; i <= oldLen; i++ {
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for j := 1; j <= newLen; j++ {
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if oldLines[i-1] == newLines[j-1] {
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dp[i][j] = dp[i-1][j-1] + 1
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} else {
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dp[i][j] = max(dp[i-1][j], dp[i][j-1])
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}
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}
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}
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// 回溯找出LCS
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var lcs []LCSEntry
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i, j := oldLen, newLen
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for i > 0 && j > 0 {
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if oldLines[i-1] == newLines[j-1] {
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lcs = append([]LCSEntry{{OldIndex: i - 1, NewIndex: j - 1}}, lcs...)
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i--
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j--
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} else if dp[i-1][j] > dp[i][j-1] {
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i--
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} else {
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j--
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}
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}
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return lcs
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}
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// max 返回两个整数中的较大值
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func max(a, b int) int {
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if a > b {
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return a
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}
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return b
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}
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// estimateChangedTokens 估计变更的token数量
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// 这里使用简单的单词分割来估计
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func estimateChangedTokens(edits []Edit) int {
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tokenCount := 0
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for _, edit := range edits {
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switch edit.Type {
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case EditInsert, EditDelete:
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// 简单地将内容按空白字符分割成单词
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words := splitIntoWords(edit.Content)
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tokenCount += len(words)
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}
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}
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return tokenCount
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}
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// splitIntoWords 将文本分割成单词
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func splitIntoWords(text string) []string {
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var words []string
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var currentWord string
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// 简单的状态机:
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// - 如果是字母、数字或下划线，添加到当前单词
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// - 否则，结束当前单词并开始新单词
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for _, char := range text {
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if isWordChar(char) {
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currentWord += string(char)
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} else {
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if currentWord != "" {
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words = append(words, currentWord)
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currentWord = ""
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}
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}
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}
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// 添加最后一个单词（如果有）
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if currentWord != "" {
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words = append(words, currentWord)
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}
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return words
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}
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// isWordChar 判断字符是否是单词字符（字母、数字或下划线）
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func isWordChar(char rune) bool {
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return (char >= 'a' && char <= 'z') ||
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(char >= 'A' && char <= 'Z') ||
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(char >= '0' && char <= '9') ||
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char == '_'
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}
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