129 lines
2.5 KiB
Go
129 lines
2.5 KiB
Go
package packd
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import (
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"bytes"
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"fmt"
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"io"
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"os"
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"time"
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"github.com/pkg/errors"
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)
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var _ File = &virtualFile{}
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var _ io.Reader = &virtualFile{}
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var _ io.Writer = &virtualFile{}
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var _ fmt.Stringer = &virtualFile{}
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type virtualFile struct {
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io.Reader
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name string
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info fileInfo
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original []byte
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}
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func (f virtualFile) Name() string {
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return f.name
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}
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func (f *virtualFile) Seek(offset int64, whence int) (int64, error) {
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return f.Reader.(*bytes.Reader).Seek(offset, whence)
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}
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func (f virtualFile) FileInfo() (os.FileInfo, error) {
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return f.info, nil
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}
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func (f *virtualFile) Close() error {
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return nil
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}
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func (f virtualFile) Readdir(count int) ([]os.FileInfo, error) {
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return []os.FileInfo{f.info}, nil
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}
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func (f virtualFile) Stat() (os.FileInfo, error) {
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return f.info, nil
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}
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func (f virtualFile) String() string {
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return string(f.original)
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}
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// Read reads the next len(p) bytes from the virtualFile and
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// rewind read offset to 0 when it met EOF.
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func (f *virtualFile) Read(p []byte) (int, error) {
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i, err := f.Reader.Read(p)
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if i == 0 || err == io.EOF {
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f.Seek(0, io.SeekStart)
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}
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return i, err
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}
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// Write copies byte slice p to content of virtualFile.
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func (f *virtualFile) Write(p []byte) (int, error) {
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return f.write(p)
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}
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// write copies byte slice or data from io.Reader to content of the
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// virtualFile and update related information of the virtualFile.
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func (f *virtualFile) write(d interface{}) (c int, err error) {
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bb := &bytes.Buffer{}
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switch d.(type) {
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case []byte:
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c, err = bb.Write(d.([]byte))
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case io.Reader:
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if d != nil {
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i64, e := io.Copy(bb, d.(io.Reader))
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c = int(i64)
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err = e
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}
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default:
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err = errors.New("unknown type of argument")
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}
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if err != nil {
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return c, errors.WithStack(err)
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}
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f.info.size = int64(c)
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f.info.modTime = time.Now()
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f.original = bb.Bytes()
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f.Reader = bytes.NewReader(f.original)
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return c, nil
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}
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// NewFile returns a new "virtual" file
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func NewFile(name string, r io.Reader) (File, error) {
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return buildFile(name, r)
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}
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// NewDir returns a new "virtual" directory
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func NewDir(name string) (File, error) {
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v, err := buildFile(name, nil)
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if err != nil {
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return v, errors.WithStack(err)
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}
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v.info.isDir = true
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return v, nil
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}
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func buildFile(name string, r io.Reader) (*virtualFile, error) {
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vf := &virtualFile{
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name: name,
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info: fileInfo{
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Path: name,
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modTime: time.Now(),
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},
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}
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var err error
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if r != nil {
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_, err = vf.write(r)
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} else {
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_, err = vf.write([]byte{}) // for safety
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}
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return vf, errors.Wrap(err, "could not make virtual file")
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}
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