github.com/hasnat/dolt/go@v0.0.0-20210628190320-9eb5d843fbb7/store/util/progressreader/reader.go (about)

     1  // Copyright 2019 Dolthub, Inc.
     2  //
     3  // Licensed under the Apache License, Version 2.0 (the "License");
     4  // you may not use this file except in compliance with the License.
     5  // You may obtain a copy of the License at
     6  //
     7  //     http://www.apache.org/licenses/LICENSE-2.0
     8  //
     9  // Unless required by applicable law or agreed to in writing, software
    10  // distributed under the License is distributed on an "AS IS" BASIS,
    11  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    12  // See the License for the specific language governing permissions and
    13  // limitations under the License.
    14  //
    15  // This file incorporates work covered by the following copyright and
    16  // permission notice:
    17  //
    18  // Copyright 2016 Attic Labs, Inc. All rights reserved.
    19  // Licensed under the Apache License, version 2.0:
    20  // http://www.apache.org/licenses/LICENSE-2.0
    21  
    22  // Package progressreader provides an io.Reader that reports progress to a callback
    23  package progressreader
    24  
    25  import (
    26  	"io"
    27  	"time"
    28  
    29  	"github.com/dolthub/dolt/go/store/util/status"
    30  )
    31  
    32  type Callback func(seen uint64)
    33  
    34  func New(inner io.Reader, cb Callback) io.Reader {
    35  	return &reader{inner, uint64(0), time.Time{}, cb}
    36  }
    37  
    38  type reader struct {
    39  	inner    io.Reader
    40  	seen     uint64
    41  	lastTime time.Time
    42  	cb       Callback
    43  }
    44  
    45  func (r *reader) Read(p []byte) (n int, err error) {
    46  	n, err = r.inner.Read(p)
    47  	r.seen += uint64(n)
    48  
    49  	if now := time.Now(); now.Sub(r.lastTime) >= status.Rate || err == io.EOF {
    50  		r.cb(r.seen)
    51  		r.lastTime = now
    52  	}
    53  	return
    54  }