/
reader.go
88 lines (68 loc) · 1.64 KB
/
reader.go
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package reader
import (
"github.com/D3rus/go-library/file"
"io"
"os"
"sync"
)
//go:generate mockgen -package=reader -destination=mock_reader_test.go github.com/D3rus/go-library/file Reader
//go:generate mockgen -package=reader -destination=mock_collection_test.go github.com/D3rus/go-library/file Collection
type Reader struct {
collection file.Collection
file *os.File
mutex *sync.Mutex
}
func New(collection file.Collection, options ...file.ReaderOption) (file.Reader, error) {
var reader file.Reader = NewReader(collection)
var err error
for _, option := range options {
reader, err = option(reader)
if err != nil {
return nil, err
}
}
return reader, nil
}
func NewReader(collection file.Collection) *Reader {
return &Reader{collection: collection, mutex: &sync.Mutex{}}
}
func (reader *Reader) Collection() file.Collection {
return reader.collection
}
func (reader *Reader) Read(buffer []byte) (int, error) {
f, err := reader.File()
if err != nil {
return 0, err
}
length, err := f.Read(buffer)
if err != nil && err == io.EOF {
if err := reader.Close(); err != nil {
return 0, err
}
return 0, file.NextShardError
}
return length, err
}
func (reader *Reader) Close() error {
reader.mutex.Lock()
defer reader.mutex.Unlock()
if reader.file != nil {
if err := reader.file.Close(); err != nil {
return err
}
}
reader.file = nil
return nil
}
func (reader *Reader) File() (*os.File, error) {
reader.mutex.Lock()
defer reader.mutex.Unlock()
if reader.file == nil {
file, err := reader.collection.Next()
if err != nil {
return nil, err
}
reader.file = file
}
return reader.file, nil
}