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73 lines
1.5 KiB
73 lines
1.5 KiB
// 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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"os" |
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"github.com/pkg/errors" |
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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, errors.Wrap(err, "try lock file") |
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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, errors.Wrap(err, "stat") |
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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, errors.Wrap(err, "mmap") |
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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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