mirror of
https://github.com/prometheus/prometheus.git
synced 2024-11-13 17:14:05 -08:00
73 lines
1.5 KiB
Go
73 lines
1.5 KiB
Go
// Copyright 2018 The Prometheus 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 fileutil
|
|
|
|
import (
|
|
"fmt"
|
|
"os"
|
|
)
|
|
|
|
type MmapFile struct {
|
|
f *os.File
|
|
b []byte
|
|
}
|
|
|
|
func OpenMmapFile(path string) (*MmapFile, error) {
|
|
return OpenMmapFileWithSize(path, 0)
|
|
}
|
|
|
|
func OpenMmapFileWithSize(path string, size int) (mf *MmapFile, retErr error) {
|
|
f, err := os.Open(path)
|
|
if err != nil {
|
|
return nil, fmt.Errorf("try lock file: %w", err)
|
|
}
|
|
defer func() {
|
|
if retErr != nil {
|
|
f.Close()
|
|
}
|
|
}()
|
|
if size <= 0 {
|
|
info, err := f.Stat()
|
|
if err != nil {
|
|
return nil, fmt.Errorf("stat: %w", err)
|
|
}
|
|
size = int(info.Size())
|
|
}
|
|
|
|
b, err := mmap(f, size)
|
|
if err != nil {
|
|
return nil, fmt.Errorf("mmap, size %d: %w", size, err)
|
|
}
|
|
|
|
return &MmapFile{f: f, b: b}, nil
|
|
}
|
|
|
|
func (f *MmapFile) Close() error {
|
|
err0 := munmap(f.b)
|
|
err1 := f.f.Close()
|
|
|
|
if err0 != nil {
|
|
return err0
|
|
}
|
|
return err1
|
|
}
|
|
|
|
func (f *MmapFile) File() *os.File {
|
|
return f.f
|
|
}
|
|
|
|
func (f *MmapFile) Bytes() []byte {
|
|
return f.b
|
|
}
|