重构fetcher接口

download/base/constants.go

@@ -0,0 +1,30 @@
+package base
+
+import "errors"
+
+type Status int
+
+const (
+	DownloadStatusReady Status = iota
+	DownloadStatusStart
+	DownloadStatusPause
+	DownloadStatusError
+	DownloadStatusDone
+)
+
+const (
+	HttpCodeOK             = 200
+	HttpCodePartialContent = 206
+
+	HttpHeaderRange              = "Range"
+	HttpHeaderContentLength      = "Content-Length"
+	HttpHeaderContentRange       = "Content-Range"
+	HttpHeaderContentDisposition = "Content-Disposition"
+
+	HttpHeaderRangeFormat = "bytes=%d-%d"
+)
+
+var (
+	PauseErr  = errors.New("pause")
+	DeleteErr = errors.New("delete")
+)

download/base/controller.go

@@ -0,0 +1,144 @@
+package base
+
+import (
+	"golang.org/x/net/proxy"
+	"net"
+	"os"
+	"time"
+)
+
+type Controller interface {
+	Touch(name string, size int64) (file *os.File, err error)
+	Open(name string) (file *os.File, err error)
+	Write(name string, offset int64, buf []byte) (int, error)
+	Close(name string) error
+	ContextDialer() (proxy.Dialer, error)
+}
+
+// 下载请求
+type Request struct {
+	// 下载链接
+	URL string
+	// 附加信息
+	Extra interface{}
+}
+
+// 资源信息
+type Resource struct {
+	Req *Request
+	// 资源总大小
+	Size int64
+	// 是否支持断点下载
+	Range bool
+	// 资源所包含的文件列表
+	Files []*FileInfo
+}
+
+type Options struct {
+	// 保存文件名
+	Name string
+	// 保存目录
+	Path string
+	// 并发连接数
+	Connections int
+}
+
+type FileInfo struct {
+	Name string
+	Path string
+	Size int64
+}
+
+type DefaultController struct {
+	Files map[string]*os.File
+}
+
+func NewController() *DefaultController {
+	return &DefaultController{Files: make(map[string]*os.File)}
+}
+
+func (c *DefaultController) Touch(name string, size int64) (file *os.File, err error) {
+	file, err = os.Create(name)
+	if size > 0 {
+		err = os.Truncate(name, size)
+		if err != nil {
+			return nil, err
+		}
+	}
+	if err == nil {
+		c.Files[name] = file
+	}
+	return
+}
+
+func (c *DefaultController) Open(name string) (file *os.File, err error) {
+	file, err = os.OpenFile(name, os.O_RDWR, os.ModePerm)
+	if err == nil {
+		c.Files[name] = file
+	}
+	return
+}
+
+func (c *DefaultController) Write(name string, offset int64, buf []byte) (int, error) {
+	return c.Files[name].WriteAt(buf, offset)
+}
+
+func (c *DefaultController) Close(name string) error {
+	err := c.Files[name].Close()
+	delete(c.Files, name)
+	return err
+}
+
+func (c *DefaultController) ContextDialer() (proxy.Dialer, error) {
+	// return proxy.SOCKS5("tpc", "127.0.0.1:9999", nil, nil)
+	var dialer proxy.Dialer
+	return &DialerWarp{dialer: dialer}, nil
+}
+
+type DialerWarp struct {
+	dialer proxy.Dialer
+}
+
+type ConnWarp struct {
+	conn net.Conn
+}
+
+func (c *ConnWarp) Read(b []byte) (n int, err error) {
+	return c.conn.Read(b)
+}
+
+func (c *ConnWarp) Write(b []byte) (n int, err error) {
+	return c.conn.Write(b)
+}
+
+func (c *ConnWarp) Close() error {
+	return c.conn.Close()
+}
+
+func (c *ConnWarp) LocalAddr() net.Addr {
+	return c.conn.LocalAddr()
+}
+
+func (c *ConnWarp) RemoteAddr() net.Addr {
+	return c.conn.RemoteAddr()
+}
+
+func (c *ConnWarp) SetDeadline(t time.Time) error {
+	return c.conn.SetDeadline(t)
+}
+
+func (c *ConnWarp) SetReadDeadline(t time.Time) error {
+	return c.conn.SetReadDeadline(t)
+}
+
+func (c *ConnWarp) SetWriteDeadline(t time.Time) error {
+	return c.conn.SetWriteDeadline(t)
+}
+
+func (d *DialerWarp) Dial(network, addr string) (c net.Conn, err error) {
+	conn, err := d.dialer.Dial(network, addr)
+	if err != nil {
+		return nil, err
+	}
+	return &ConnWarp{conn: conn}, nil
+}

download/base/event.go

@@ -0,0 +1,5 @@
+package base
+
+type Event interface {
+	Status() Status
+}

download/base/fetcher.go

@@ -0,0 +1,22 @@
+package base
+
+// 对应协议的下载支持
+type Fetcher interface {
+	Init(ctl Controller)
+	// 解析请求
+	Resolve(req *Request) (*Resource, error)
+	// 创建任务
+	Create(res *Resource, opts *Options) error
+	Start() error
+	Pause() error
+	Continue() error
+	Delete() error
+}
+
+type DefaultFetcher struct {
+	Ctl Controller
+}
+
+func (f *DefaultFetcher) Init(ctl Controller) {
+	f.Ctl = ctl
+}