mirror of https://github.com/schollz/croc.git
102 lines
2.2 KiB
Go
102 lines
2.2 KiB
Go
package main
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import (
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"crypto/md5"
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"fmt"
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"io"
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"os"
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)
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// CopyFile copies a file from src to dst. If src and dst files exist, and are
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// the same, then return success. Otherise, attempt to create a hard link
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// between the two files. If that fail, copy the file contents from src to dst.
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func CopyFile(src, dst string) (err error) {
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sfi, err := os.Stat(src)
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if err != nil {
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return
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}
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if !sfi.Mode().IsRegular() {
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// cannot copy non-regular files (e.g., directories,
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// symlinks, devices, etc.)
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return fmt.Errorf("CopyFile: non-regular source file %s (%q)", sfi.Name(), sfi.Mode().String())
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}
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dfi, err := os.Stat(dst)
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if err != nil {
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if !os.IsNotExist(err) {
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return
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}
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} else {
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if !(dfi.Mode().IsRegular()) {
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return fmt.Errorf("CopyFile: non-regular destination file %s (%q)", dfi.Name(), dfi.Mode().String())
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}
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if os.SameFile(sfi, dfi) {
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return
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}
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}
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if err = os.Link(src, dst); err == nil {
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return
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}
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err = copyFileContents(src, dst)
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return
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}
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// copyFileContents copies the contents of the file named src to the file named
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// by dst. The file will be created if it does not already exist. If the
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// destination file exists, all it's contents will be replaced by the contents
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// of the source file.
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func copyFileContents(src, dst string) (err error) {
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in, err := os.Open(src)
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if err != nil {
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return
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}
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defer in.Close()
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out, err := os.Create(dst)
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if err != nil {
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return
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}
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defer func() {
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cerr := out.Close()
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if err == nil {
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err = cerr
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}
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}()
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if _, err = io.Copy(out, in); err != nil {
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return
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}
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err = out.Sync()
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return
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}
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// HashFile does a md5 hash on the file
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// from https://golang.org/pkg/crypto/md5/#example_New_file
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func HashFile(filename string) (hash string, err error) {
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f, err := os.Open(filename)
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if err != nil {
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return
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}
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defer f.Close()
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h := md5.New()
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if _, err = io.Copy(h, f); err != nil {
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return
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}
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hash = fmt.Sprintf("%x", h.Sum(nil))
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return
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}
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// FileSize returns the size of a file
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func FileSize(filename string) (int, error) {
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f, err := os.Open(filename)
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if err != nil {
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return -1, err
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}
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defer f.Close()
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fi, err := f.Stat()
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if err != nil {
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return -1, err
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}
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size := int(fi.Size())
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return size, nil
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}
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