github.com/hasnat/dolt/go@v0.0.0-20210628190320-9eb5d843fbb7/store/blobstore/blobstore.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  package blobstore
    16  
    17  import (
    18  	"bytes"
    19  	"context"
    20  	"io"
    21  	"io/ioutil"
    22  )
    23  
    24  // Blobstore is an interface for storing and retrieving blobs of data by key
    25  type Blobstore interface {
    26  	Exists(ctx context.Context, key string) (bool, error)
    27  	Get(ctx context.Context, key string, br BlobRange) (io.ReadCloser, string, error)
    28  	Put(ctx context.Context, key string, reader io.Reader) (string, error)
    29  	CheckAndPut(ctx context.Context, expectedVersion, key string, reader io.Reader) (string, error)
    30  }
    31  
    32  // GetBytes is a utility method calls bs.Get and handles reading the data from the returned
    33  // io.ReadCloser and closing it.
    34  func GetBytes(ctx context.Context, bs Blobstore, key string, br BlobRange) ([]byte, string, error) {
    35  	rc, ver, err := bs.Get(ctx, key, br)
    36  
    37  	if err != nil || rc == nil {
    38  		return nil, ver, err
    39  	}
    40  
    41  	defer rc.Close()
    42  	data, err := ioutil.ReadAll(rc)
    43  
    44  	if err != nil {
    45  		return nil, "", err
    46  	}
    47  
    48  	return data, ver, nil
    49  }
    50  
    51  // PutBytes is a utility method calls bs.Put by wrapping the supplied []byte in an io.Reader
    52  func PutBytes(ctx context.Context, bs Blobstore, key string, data []byte) (string, error) {
    53  	reader := bytes.NewReader(data)
    54  	return bs.Put(ctx, key, reader)
    55  }