minio/internal/ioutil/read_file.go

110 lines
2.9 KiB
Go

// Copyright (c) 2015-2021 MinIO, Inc.
//
// This file is part of MinIO Object Storage stack
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU Affero General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Affero General Public License for more details.
//
// You should have received a copy of the GNU Affero General Public License
// along with this program. If not, see <http://www.gnu.org/licenses/>.
package ioutil
import (
"io"
"io/fs"
"os"
"github.com/minio/minio/internal/disk"
)
var (
// OpenFileDirectIO allows overriding default function.
OpenFileDirectIO = disk.OpenFileDirectIO
// OsOpen allows overriding default function.
OsOpen = os.Open
// OsOpenFile allows overriding default function.
OsOpenFile = os.OpenFile
)
// ReadFileWithFileInfo reads the named file and returns the contents.
// A successful call returns err == nil, not err == EOF.
// Because ReadFile reads the whole file, it does not treat an EOF from Read
// as an error to be reported.
func ReadFileWithFileInfo(name string) ([]byte, fs.FileInfo, error) {
f, err := OsOpenFile(name, readMode, 0o666)
if err != nil {
return nil, nil, err
}
defer f.Close()
st, err := f.Stat()
if err != nil {
return nil, nil, err
}
dst := make([]byte, st.Size())
_, err = io.ReadFull(f, dst)
return dst, st, err
}
// ReadFile reads the named file and returns the contents.
// A successful call returns err == nil, not err == EOF.
// Because ReadFile reads the whole file, it does not treat an EOF from Read
// as an error to be reported.
//
// passes NOATIME flag for reads on Unix systems to avoid atime updates.
func ReadFile(name string) ([]byte, error) {
if !disk.ODirectPlatform {
// Don't wrap with un-needed buffer.
// Don't use os.ReadFile, since it doesn't pass NO_ATIME when present.
f, err := OsOpenFile(name, readMode, 0o666)
if err != nil {
return nil, err
}
defer f.Close()
st, err := f.Stat()
if err != nil {
return io.ReadAll(f)
}
dst := make([]byte, st.Size())
_, err = io.ReadFull(f, dst)
return dst, err
}
f, err := OpenFileDirectIO(name, readMode, 0o666)
if err != nil {
// fallback if there is an error to read
// 'name' with O_DIRECT
f, err = OsOpenFile(name, readMode, 0o666)
if err != nil {
return nil, err
}
}
r := &ODirectReader{
File: f,
SmallFile: true,
}
defer r.Close()
st, err := f.Stat()
if err != nil {
return io.ReadAll(r)
}
// Select bigger blocks when reading would do more than 2 reads.
r.SmallFile = st.Size() <= BlockSizeSmall*2
dst := make([]byte, st.Size())
_, err = io.ReadFull(r, dst)
return dst, err
}