feat(offline_download): add simple http tool (close #4002)

internal/offline_download/tool/base.go

@@ -35,6 +35,9 @@ type Tool interface {
 	Remove(task *DownloadTask) error
 	// Status return the status of the download task, if an error occurred, return the error in Status.Err
 	Status(task *DownloadTask) (*Status, error)
+
+	// Run for simple http download
+	Run(task *DownloadTask) error
 }
 
 type GetFileser interface {

internal/offline_download/tool/download.go

@@ -2,6 +2,7 @@ package tool
 
 import (
 	"fmt"
+	"github.com/alist-org/alist/v3/internal/errs"
 	"github.com/pkg/errors"
 	log "github.com/sirupsen/logrus"
 	"github.com/xhofe/tache"
@@ -25,6 +26,12 @@ type DownloadTask struct {
 }
 
 func (t *DownloadTask) Run() error {
+	if err := t.tool.Run(t); !errs.IsNotSupportError(err) {
+		if err == nil {
+			return t.Complete()
+		}
+		return err
+	}
 	t.Signal = make(chan int)
 	t.finish = make(chan struct{})
 	defer func() {