dragonfly/pkg/ratelimiter/limitreader/limit_reader.go

100 lines
2.6 KiB
Go

/*
* Copyright 2020 The Dragonfly Authors
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package limitreader
import (
"crypto/md5"
"hash"
"io"
"d7y.io/dragonfly/v2/pkg/ratelimiter/ratelimiter"
"d7y.io/dragonfly/v2/pkg/util/digestutils"
)
// NewLimitReader creates a LimitReader.
// src: reader
// rate: bytes/second
func NewLimitReader(src io.Reader, rate int64, calculateMd5 bool) *LimitReader {
return NewLimitReaderWithLimiter(newRateLimiterWithDefaultWindow(rate), src, calculateMd5)
}
// NewLimitReaderWithLimiter creates LimitReader with a rateLimiter.
// src: reader
// rate: bytes/second
func NewLimitReaderWithLimiter(rl *ratelimiter.RateLimiter, src io.Reader, calculateMd5 bool) *LimitReader {
var md5sum hash.Hash
if calculateMd5 {
md5sum = md5.New()
}
return &LimitReader{
Src: src,
Limiter: rl,
md5sum: md5sum,
}
}
// NewLimitReaderWithMD5Sum creates LimitReader with a md5 sum.
// src: reader
// rate: bytes/second
func NewLimitReaderWithMD5Sum(src io.Reader, rate int64, md5sum hash.Hash) *LimitReader {
return NewLimitReaderWithLimiterAndMD5Sum(src, newRateLimiterWithDefaultWindow(rate), md5sum)
}
// NewLimitReaderWithLimiterAndMD5Sum creates LimitReader with rateLimiter and md5 sum.
// src: reader
// rate: bytes/second
func NewLimitReaderWithLimiterAndMD5Sum(src io.Reader, rl *ratelimiter.RateLimiter, md5sum hash.Hash) *LimitReader {
return &LimitReader{
Src: src,
Limiter: rl,
md5sum: md5sum,
}
}
func newRateLimiterWithDefaultWindow(rate int64) *ratelimiter.RateLimiter {
return ratelimiter.NewRateLimiter(ratelimiter.TransRate(rate), 2)
}
// LimitReader reads stream with RateLimiter.
type LimitReader struct {
Src io.Reader
Limiter *ratelimiter.RateLimiter
md5sum hash.Hash
}
func (lr *LimitReader) Read(p []byte) (n int, err error) {
n, e := lr.Src.Read(p)
if e != nil && e != io.EOF {
return n, e
}
if n > 0 {
if lr.md5sum != nil {
lr.md5sum.Write(p[:n])
}
lr.Limiter.AcquireBlocking(int64(n))
}
return n, e
}
// Md5 calculates the md5 of all contents read.
func (lr *LimitReader) Md5() string {
if lr.md5sum != nil {
return digestutils.ToHashString(lr.md5sum)
}
return ""
}