1.4.5.2

EdgeNode/internal/caches/partial_ranges.go

@@ -0,0 +1,270 @@
+// Copyright 2022 Liuxiangchao iwind.liu@gmail.com. All rights reserved.
+
+package caches
+
+import (
+	"bytes"
+	"encoding/json"
+	rangeutils "github.com/TeaOSLab/EdgeNode/internal/utils/ranges"
+	"github.com/iwind/TeaGo/types"
+	"strconv"
+)
+
+// PartialRanges 内容分区范围定义
+type PartialRanges struct {
+	Version    int        `json:"version"`    // 版本号
+	Ranges     [][2]int64 `json:"ranges"`     // 范围
+	BodySize   int64      `json:"bodySize"`   // 总长度
+	ContentMD5 string     `json:"contentMD5"` // 内容md5
+}
+
+// NewPartialRanges 获取新对象
+func NewPartialRanges(expiresAt int64) *PartialRanges {
+	return &PartialRanges{
+		Ranges:  [][2]int64{},
+		Version: 2,
+	}
+}
+
+// NewPartialRangesFromData 从数据中解析范围
+func NewPartialRangesFromData(data []byte) (*PartialRanges, error) {
+	var rs = NewPartialRanges(0)
+	for {
+		var index = bytes.IndexRune(data, '\n')
+		if index < 0 {
+			break
+		}
+		var line = data[:index]
+		var colonIndex = bytes.IndexRune(line, ':')
+		if colonIndex > 0 {
+			switch string(line[:colonIndex]) {
+			case "v": // 版本号
+				rs.Version = types.Int(line[colonIndex+1:])
+			case "b": // 总长度
+				rs.BodySize = types.Int64(line[colonIndex+1:])
+			case "r": // 范围信息
+				var commaIndex = bytes.IndexRune(line, ',')
+				if commaIndex > 0 {
+					rs.Ranges = append(rs.Ranges, [2]int64{types.Int64(line[colonIndex+1 : commaIndex]), types.Int64(line[commaIndex+1:])})
+				}
+			case "m": // Content-MD5
+				rs.ContentMD5 = string(line[colonIndex+1:])
+			}
+		}
+		data = data[index+1:]
+		if len(data) == 0 {
+			break
+		}
+	}
+	return rs, nil
+}
+
+// NewPartialRangesFromJSON 从JSON中解析范围
+func NewPartialRangesFromJSON(data []byte) (*PartialRanges, error) {
+	var rs = NewPartialRanges(0)
+	err := json.Unmarshal(data, &rs)
+	if err != nil {
+		return nil, err
+	}
+	rs.Version = 0
+
+	return rs, nil
+}
+
+// NewPartialRangesFromFile 从文件中加载范围信息
+func NewPartialRangesFromFile(path string) (*PartialRanges, error) {
+	data, err := SharedPartialRangesQueue.Get(path)
+	if err != nil {
+		return nil, err
+	}
+	if len(data) == 0 {
+		return NewPartialRanges(0), nil
+	}
+
+	// 兼容老的JSON格式
+	if data[0] == '{' {
+		return NewPartialRangesFromJSON(data)
+	}
+
+	// 新的格式
+	return NewPartialRangesFromData(data)
+}
+
+// Add 添加新范围
+func (this *PartialRanges) Add(begin int64, end int64) {
+	if begin > end {
+		begin, end = end, begin
+	}
+
+	var nr = [2]int64{begin, end}
+
+	var count = len(this.Ranges)
+	if count == 0 {
+		this.Ranges = [][2]int64{nr}
+		return
+	}
+
+	// insert
+	var index = -1
+	for i, r := range this.Ranges {
+		if r[0] > begin || (r[0] == begin && r[1] >= end) {
+			index = i
+			this.Ranges = append(this.Ranges, [2]int64{})
+			copy(this.Ranges[index+1:], this.Ranges[index:])
+			this.Ranges[index] = nr
+			break
+		}
+	}
+
+	if index == -1 {
+		index = count
+		this.Ranges = append(this.Ranges, nr)
+	}
+
+	this.merge(index)
+}
+
+// Contains 检查是否包含某个范围
+func (this *PartialRanges) Contains(begin int64, end int64) bool {
+	if len(this.Ranges) == 0 {
+		return false
+	}
+
+	for _, r2 := range this.Ranges {
+		if r2[0] <= begin && r2[1] >= end {
+			return true
+		}
+	}
+
+	return false
+}
+
+// Nearest 查找最近的某个范围
+func (this *PartialRanges) Nearest(begin int64, end int64) (r [2]int64, ok bool) {
+	if len(this.Ranges) == 0 {
+		return
+	}
+
+	for _, r2 := range this.Ranges {
+		if r2[0] <= begin && r2[1] > begin {
+			r = [2]int64{begin, this.min(end, r2[1])}
+			ok = true
+			return
+		}
+	}
+	return
+}
+
+// FindRangeAtPosition 查找在某个位置上的范围
+func (this *PartialRanges) FindRangeAtPosition(position int64) (r rangeutils.Range, ok bool) {
+	if len(this.Ranges) == 0 || position < 0 {
+		return
+	}
+
+	for _, r2 := range this.Ranges {
+		if r2[0] <= position && r2[1] > position {
+			return [2]int64{position, r2[1]}, true
+		}
+	}
+
+	return
+}
+
+// 转换为字符串
+func (this *PartialRanges) String() string {
+	var s = "v:" + strconv.Itoa(this.Version) + "\n" + // version
+		"b:" + this.formatInt64(this.BodySize) + "\n" // bodySize
+	if len(this.ContentMD5) > 0 {
+		s += "m:" + this.ContentMD5 + "\n" // Content-MD5
+	}
+	for _, r := range this.Ranges {
+		s += "r:" + this.formatInt64(r[0]) + "," + this.formatInt64(r[1]) + "\n" // range
+	}
+	return s
+}
+
+// Bytes 将内容转换为字节
+func (this *PartialRanges) Bytes() []byte {
+	return []byte(this.String())
+}
+
+// WriteToFile 写入到文件中
+func (this *PartialRanges) WriteToFile(path string) error {
+	SharedPartialRangesQueue.Put(path, this.Bytes())
+	return nil
+}
+
+// Max 获取最大位置
+func (this *PartialRanges) Max() int64 {
+	if len(this.Ranges) > 0 {
+		return this.Ranges[len(this.Ranges)-1][1]
+	}
+	return 0
+}
+
+// Reset 重置范围信息
+func (this *PartialRanges) Reset() {
+	this.Ranges = [][2]int64{}
+}
+
+// IsCompleted 是否已下载完整
+func (this *PartialRanges) IsCompleted() bool {
+	return len(this.Ranges) == 1 && this.Ranges[0][0] == 0 && this.Ranges[0][1] == this.BodySize-1
+}
+
+func (this *PartialRanges) merge(index int) {
+	// forward
+	var lastIndex = index
+	for i := index; i >= 1; i-- {
+		var curr = this.Ranges[i]
+		var prev = this.Ranges[i-1]
+		var w1 = this.w(curr)
+		var w2 = this.w(prev)
+		if w1+w2 >= this.max(curr[1], prev[1])-this.min(curr[0], prev[0])-1 {
+			prev = [2]int64{this.min(curr[0], prev[0]), this.max(curr[1], prev[1])}
+			this.Ranges[i-1] = prev
+			this.Ranges = append(this.Ranges[:i], this.Ranges[i+1:]...)
+			lastIndex = i - 1
+		} else {
+			break
+		}
+	}
+
+	// backward
+	index = lastIndex
+	for index < len(this.Ranges)-1 {
+		var curr = this.Ranges[index]
+		var next = this.Ranges[index+1]
+		var w1 = this.w(curr)
+		var w2 = this.w(next)
+		if w1+w2 >= this.max(curr[1], next[1])-this.min(curr[0], next[0])-1 {
+			curr = [2]int64{this.min(curr[0], next[0]), this.max(curr[1], next[1])}
+			this.Ranges = append(this.Ranges[:index], this.Ranges[index+1:]...)
+			this.Ranges[index] = curr
+		} else {
+			break
+		}
+	}
+}
+
+func (this *PartialRanges) w(r [2]int64) int64 {
+	return r[1] - r[0]
+}
+
+func (this *PartialRanges) min(n1 int64, n2 int64) int64 {
+	if n1 <= n2 {
+		return n1
+	}
+	return n2
+}
+
+func (this *PartialRanges) max(n1 int64, n2 int64) int64 {
+	if n1 >= n2 {
+		return n1
+	}
+	return n2
+}
+
+func (this *PartialRanges) formatInt64(i int64) string {
+	return strconv.FormatInt(i, 10)
+}