package controller import ( "bytes" "errors" _ "golang.org/x/image/webp" "image" _ "image/gif" _ "image/jpeg" _ "image/png" "io/ioutil" "net/http" "pikapika/main/database/comic_center" "sync" ) var mutexCounter = -1 var busMutex *sync.Mutex var subMutexes []*sync.Mutex func init() { busMutex = &sync.Mutex{} for i := 0; i < 5; i++ { subMutexes = append(subMutexes, &sync.Mutex{}) } } // takeMutex 下载图片获取一个锁, 这样只能同时下载5张图片 func takeMutex() *sync.Mutex { busMutex.Lock() defer busMutex.Unlock() mutexCounter = (mutexCounter + 1) % len(subMutexes) return subMutexes[mutexCounter] } func decodeInfoFromBuff(buff []byte) (image.Image, string, error) { buffer := bytes.NewBuffer(buff) return image.Decode(buffer) } func decodeFromFile(path string) ([]byte, image.Image, string, error) { b, e := ioutil.ReadFile(path) if e != nil { return nil, nil, "", e } i, f, e := decodeInfoFromBuff(b) if e != nil { return nil, nil, "", e } return b, i, f, e } // 下载图片并decode func decodeFromUrl(fileServer string, path string) ([]byte, image.Image, string, error) { m := takeMutex() m.Lock() defer m.Unlock() request, err := http.NewRequest("GET", fileServer+"/static/"+path, nil) if err != nil { return nil, nil, "", err } response, err := client.Do(request) if err != nil { return nil, nil, "", err } defer response.Body.Close() if response.StatusCode != 200 { return nil, nil, "", errors.New("code is not 200") } buff, err := ioutil.ReadAll(response.Body) if err != nil { return nil, nil, "", err } img, format, err := decodeInfoFromBuff(buff) if err != nil { return nil, nil, "", err } return buff, img, format, err } // decodeFromCache 仅下载使用 func decodeFromCache(fileServer string, path string) ([]byte, image.Image, string, error) { cache := comic_center.FindRemoteImage(fileServer, path) if cache != nil { buff, err := ioutil.ReadFile(remotePath(cache.LocalPath)) if err != nil { return nil, nil, "", err } img, format, err := decodeInfoFromBuff(buff) if err != nil { return nil, nil, "", err } return buff, img, format, err } return nil, nil, "", errors.New("not found") }