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131 lines
2.5 KiB
131 lines
2.5 KiB
// Copyright 2014 The lldb Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package lldb // import "modernc.org/lldb"
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import (
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"io"
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"os"
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"modernc.org/mathutil"
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)
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var _ Filer = (*OSFiler)(nil)
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// OSFile is an os.File like minimal set of methods allowing to construct a
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// Filer.
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type OSFile interface {
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Name() string
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Stat() (fi os.FileInfo, err error)
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Sync() (err error)
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Truncate(size int64) (err error)
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io.Closer
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io.Reader
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io.ReaderAt
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io.Seeker
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io.Writer
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io.WriterAt
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}
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// OSFiler is like a SimpleFileFiler but based on an OSFile.
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type OSFiler struct {
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f OSFile
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nest int
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size int64 // not set if < 0
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}
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// NewOSFiler returns a Filer from an OSFile. This Filer is like the
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// SimpleFileFiler, it does not implement the transaction related methods.
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func NewOSFiler(f OSFile) (r *OSFiler) {
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return &OSFiler{
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f: f,
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size: -1,
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}
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}
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// BeginUpdate implements Filer.
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func (f *OSFiler) BeginUpdate() (err error) {
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f.nest++
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return nil
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}
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// Close implements Filer.
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func (f *OSFiler) Close() (err error) {
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if f.nest != 0 {
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return &ErrPERM{(f.Name() + ":Close")}
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}
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return f.f.Close()
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}
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// EndUpdate implements Filer.
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func (f *OSFiler) EndUpdate() (err error) {
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if f.nest == 0 {
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return &ErrPERM{(f.Name() + ":EndUpdate")}
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}
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f.nest--
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return
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}
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// Name implements Filer.
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func (f *OSFiler) Name() string {
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return f.f.Name()
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}
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// PunchHole implements Filer.
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func (f *OSFiler) PunchHole(off, size int64) (err error) {
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return
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}
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// ReadAt implements Filer.
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func (f *OSFiler) ReadAt(b []byte, off int64) (n int, err error) {
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return f.f.ReadAt(b, off)
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}
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// Rollback implements Filer.
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func (f *OSFiler) Rollback() (err error) { return }
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// Size implements Filer.
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func (f *OSFiler) Size() (n int64, err error) {
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if f.size < 0 { // boot
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fi, err := f.f.Stat()
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if err != nil {
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return 0, err
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}
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f.size = fi.Size()
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}
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return f.size, nil
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}
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// Sync implements Filer.
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func (f *OSFiler) Sync() (err error) {
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return f.f.Sync()
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}
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// Truncate implements Filer.
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func (f *OSFiler) Truncate(size int64) (err error) {
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if size < 0 {
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return &ErrINVAL{"Truncate size", size}
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}
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f.size = size
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return f.f.Truncate(size)
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}
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// WriteAt implements Filer.
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func (f *OSFiler) WriteAt(b []byte, off int64) (n int, err error) {
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if f.size < 0 { // boot
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fi, err := os.Stat(f.f.Name())
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if err != nil {
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return 0, err
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}
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f.size = fi.Size()
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}
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f.size = mathutil.MaxInt64(f.size, int64(len(b))+off)
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return f.f.WriteAt(b, off)
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}
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