mirror of
https://github.com/superseriousbusiness/gotosocial.git
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52 lines
1 KiB
Go
52 lines
1 KiB
Go
package util
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import (
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"context"
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"os"
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"reflect"
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"unsafe"
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"github.com/tetratelabs/wazero/api"
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"golang.org/x/sys/windows"
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)
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type MappedRegion struct {
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windows.Handle
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Data []byte
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addr uintptr
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}
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func MapRegion(ctx context.Context, mod api.Module, f *os.File, offset int64, size int32) (*MappedRegion, error) {
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h, err := windows.CreateFileMapping(windows.Handle(f.Fd()), nil, windows.PAGE_READWRITE, 0, 0, nil)
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if h == 0 {
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return nil, err
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}
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a, err := windows.MapViewOfFile(h, windows.FILE_MAP_WRITE,
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uint32(offset>>32), uint32(offset), uintptr(size))
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if a == 0 {
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windows.CloseHandle(h)
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return nil, err
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}
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res := &MappedRegion{Handle: h, addr: a}
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// SliceHeader, although deprecated, avoids a go vet warning.
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sh := (*reflect.SliceHeader)(unsafe.Pointer(&res.Data))
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sh.Len = int(size)
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sh.Cap = int(size)
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sh.Data = a
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return res, nil
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}
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func (r *MappedRegion) Unmap() error {
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if r.Data == nil {
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return nil
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}
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err := windows.UnmapViewOfFile(r.addr)
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if err != nil {
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return err
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}
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r.Data = nil
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return windows.CloseHandle(r.Handle)
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}
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