prometheus/db_windows.go

48 lines
1.4 KiB
Go

// Copyright 2017 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 tsdb
import (
"os"
"syscall"
"unsafe"
)
func mmap(f *os.File, sz int) ([]byte, error) {
low, high := uint32(sz), uint32(sz>>32)
h, errno := syscall.CreateFileMapping(syscall.Handle(f.Fd()), nil, syscall.PAGE_READONLY, low, high, nil)
if h == 0 {
return nil, os.NewSyscallError("CreateFileMapping", errno)
}
addr, errno := syscall.MapViewOfFile(h, syscall.FILE_MAP_READ, 0, 0, uintptr(sz))
if addr == 0 {
return nil, os.NewSyscallError("MapViewOfFile", errno)
}
if err := syscall.CloseHandle(syscall.Handle(h)); err != nil {
return nil, os.NewSyscallError("CloseHandle", err)
}
return (*[1 << 30]byte)(unsafe.Pointer(addr))[:sz], nil
}
func munmap(b []byte) error {
if err := syscall.UnmapViewOfFile((uintptr)(unsafe.Pointer(&b[0]))); err != nil {
return os.NewSyscallError("UnmapViewOfFile", err)
}
return nil
}