1// Copyright (c) 2017 Couchbase, Inc. 2// 3// Licensed under the Apache License, Version 2.0 (the "License"); 4// you may not use this file except in compliance with the License. 5// You may obtain a copy of the License at 6// 7// http://www.apache.org/licenses/LICENSE-2.0 8// 9// Unless required by applicable law or agreed to in writing, software 10// distributed under the License is distributed on an "AS IS" BASIS, 11// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 12// See the License for the specific language governing permissions and 13// limitations under the License. 14 15// +build !nommap 16 17package vellum 18 19import ( 20 "os" 21 22 mmap "github.com/edsrzf/mmap-go" 23) 24 25type mmapWrapper struct { 26 f *os.File 27 mm mmap.MMap 28} 29 30func (m *mmapWrapper) Close() (err error) { 31 if m.mm != nil { 32 err = m.mm.Unmap() 33 } 34 // try to close file even if unmap failed 35 if m.f != nil { 36 err2 := m.f.Close() 37 if err == nil { 38 // try to return first error 39 err = err2 40 } 41 } 42 return 43} 44 45func open(path string) (*FST, error) { 46 f, err := os.Open(path) 47 if err != nil { 48 return nil, err 49 } 50 mm, err := mmap.Map(f, mmap.RDONLY, 0) 51 if err != nil { 52 // mmap failed, try to close the file 53 _ = f.Close() 54 return nil, err 55 } 56 return new(mm, &mmapWrapper{ 57 f: f, 58 mm: mm, 59 }) 60} 61