101 lines
1.5 KiB
Go
101 lines
1.5 KiB
Go
package mmap
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import "os"
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type File struct {
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f *os.File
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Map []byte
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}
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func Create(path string, size int64) (*File, error) {
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f, err := os.Create(path)
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if err != nil {
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return nil, err
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}
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if err := f.Truncate(size); err != nil {
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f.Close()
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return nil, err
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}
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m, err := Map(f, PROT_READ|PROT_WRITE)
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if err != nil {
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f.Close()
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return nil, err
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}
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return &File{f, m}, nil
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}
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// Opens a mapped file in read-only mode.
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func Open(path string) (*File, error) {
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f, err := os.Open(path)
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if err != nil {
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return nil, err
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}
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m, err := Map(f, PROT_READ)
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if err != nil {
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f.Close()
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return nil, err
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}
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return &File{f, m}, nil
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}
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func OpenFile(
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path string,
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fileFlags int,
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perm os.FileMode,
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size int64, // -1 for file size.
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) (*File, error) {
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f, err := os.OpenFile(path, fileFlags, perm)
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if err != nil {
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return nil, err
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}
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writable := fileFlags|os.O_RDWR != 0 || fileFlags|os.O_WRONLY != 0
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fi, err := f.Stat()
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if err != nil {
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f.Close()
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return nil, err
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}
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if writable && size > 0 && size != fi.Size() {
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if err := f.Truncate(size); err != nil {
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f.Close()
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return nil, err
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}
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}
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mapFlags := PROT_READ
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if writable {
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mapFlags |= PROT_WRITE
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}
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m, err := Map(f, mapFlags)
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if err != nil {
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f.Close()
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return nil, err
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}
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return &File{f, m}, nil
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}
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func (f *File) Sync() error {
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return Sync(f.Map)
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}
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func (f *File) Close() error {
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if f.Map != nil {
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if err := Unmap(f.Map); err != nil {
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return err
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}
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f.Map = nil
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}
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if f.f != nil {
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if err := f.f.Close(); err != nil {
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return err
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}
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f.f = nil
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}
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return nil
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}
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