mirror of https://github.com/status-im/op-geth.git
86 lines
1.8 KiB
Go
86 lines
1.8 KiB
Go
// +build windows,!appengine
|
|
|
|
package maxminddb
|
|
|
|
// Windows support largely borrowed from mmap-go.
|
|
//
|
|
// Copyright 2011 Evan Shaw. All rights reserved.
|
|
// Use of this source code is governed by a BSD-style
|
|
// license that can be found in the LICENSE file.
|
|
|
|
import (
|
|
"errors"
|
|
"os"
|
|
"reflect"
|
|
"sync"
|
|
"unsafe"
|
|
|
|
"golang.org/x/sys/windows"
|
|
)
|
|
|
|
type memoryMap []byte
|
|
|
|
// Windows
|
|
var handleLock sync.Mutex
|
|
var handleMap = map[uintptr]windows.Handle{}
|
|
|
|
func mmap(fd int, length int) (data []byte, err error) {
|
|
h, errno := windows.CreateFileMapping(windows.Handle(fd), nil,
|
|
uint32(windows.PAGE_READONLY), 0, uint32(length), nil)
|
|
if h == 0 {
|
|
return nil, os.NewSyscallError("CreateFileMapping", errno)
|
|
}
|
|
|
|
addr, errno := windows.MapViewOfFile(h, uint32(windows.FILE_MAP_READ), 0,
|
|
0, uintptr(length))
|
|
if addr == 0 {
|
|
return nil, os.NewSyscallError("MapViewOfFile", errno)
|
|
}
|
|
handleLock.Lock()
|
|
handleMap[addr] = h
|
|
handleLock.Unlock()
|
|
|
|
m := memoryMap{}
|
|
dh := m.header()
|
|
dh.Data = addr
|
|
dh.Len = length
|
|
dh.Cap = dh.Len
|
|
|
|
return m, nil
|
|
}
|
|
|
|
func (m *memoryMap) header() *reflect.SliceHeader {
|
|
return (*reflect.SliceHeader)(unsafe.Pointer(m))
|
|
}
|
|
|
|
func flush(addr, len uintptr) error {
|
|
errno := windows.FlushViewOfFile(addr, len)
|
|
return os.NewSyscallError("FlushViewOfFile", errno)
|
|
}
|
|
|
|
func munmap(b []byte) (err error) {
|
|
m := memoryMap(b)
|
|
dh := m.header()
|
|
|
|
addr := dh.Data
|
|
length := uintptr(dh.Len)
|
|
|
|
flush(addr, length)
|
|
err = windows.UnmapViewOfFile(addr)
|
|
if err != nil {
|
|
return err
|
|
}
|
|
|
|
handleLock.Lock()
|
|
defer handleLock.Unlock()
|
|
handle, ok := handleMap[addr]
|
|
if !ok {
|
|
// should be impossible; we would've errored above
|
|
return errors.New("unknown base address")
|
|
}
|
|
delete(handleMap, addr)
|
|
|
|
e := windows.CloseHandle(windows.Handle(handle))
|
|
return os.NewSyscallError("CloseHandle", e)
|
|
}
|