mirror of
https://github.com/prometheus/prometheus.git
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73 lines
1.5 KiB
Go
73 lines
1.5 KiB
Go
// Copyright 2018 The Prometheus Authors
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package fileutil
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import (
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"fmt"
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"os"
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)
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type MmapFile struct {
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f *os.File
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b []byte
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}
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func OpenMmapFile(path string) (*MmapFile, error) {
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return OpenMmapFileWithSize(path, 0)
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}
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func OpenMmapFileWithSize(path string, size int) (mf *MmapFile, retErr error) {
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f, err := os.Open(path)
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if err != nil {
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return nil, fmt.Errorf("try lock file: %w", err)
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}
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defer func() {
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if retErr != nil {
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f.Close()
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}
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}()
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if size <= 0 {
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info, err := f.Stat()
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if err != nil {
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return nil, fmt.Errorf("stat: %w", err)
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}
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size = int(info.Size())
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}
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b, err := mmap(f, size)
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if err != nil {
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return nil, fmt.Errorf("mmap, size %d: %w", size, err)
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}
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return &MmapFile{f: f, b: b}, nil
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}
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func (f *MmapFile) Close() error {
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err0 := munmap(f.b)
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err1 := f.f.Close()
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if err0 != nil {
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return err0
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}
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return err1
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}
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func (f *MmapFile) File() *os.File {
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return f.f
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}
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func (f *MmapFile) Bytes() []byte {
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return f.b
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}
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