1set/gut

package yos

import (
    "os"
)

// MoveFile moves a file to a target file or directory. Symbolic links will be not be followed.
//
// If the target is an existing file, the target will be overwritten with the source file.
//
// If the target is an existing directory, the source file will be moved to the directory with the same name.
//
// If the target doesn't exist but its parent directory does, the source file will be moved to the parent directory with the target name.
//
// If there is an error, it will be of type *os.PathError.
func MoveFile(src, dest string) (err error) {
    return moveEntry(
        src, dest,
        isFileFi, errNotRegularFile,
        os.Remove,
        func(src, dest string) error { return bufferCopyFile(src, dest, defaultBufferSize) })
}

// MoveSymlink moves a symbolic link to a target file. It makes no attempt to read the referenced file.
//
// If the target is an existing file or link, the target will be overwritten with the source link.
//
// If the target is an existing directory, the source link will be moved to the directory with the same name.
//
// If the target doesn't exist but its parent directory does, the source link will be moved to the parent directory with the target name.
//
// If there is an error, it will be of type *os.PathError.
func MoveSymlink(src, dest string) (err error) {
    return moveEntry(
        src, dest,
        isSymlinkFi, errNotSymlink,
        os.Remove,
        func(src, dest string) error { return copySymlink(src, dest) })
}

// MoveDir moves a directory to a target directory recursively. Symbolic links inside the directories will not be followed.
//
// If the target is an existing file, it will be replaced by the source directory.
//
// If the target is an existing directory, the source directory will be moved to the directory with the same name.
//
// If the target doesn't exist but its parent directory does, the source directory will be moved to the parent directory with the target name.
//
// MoveDir stops and returns immediately if any error occurs, and the error will be of type *os.PathError.
func MoveDir(src, dest string) (err error) {
    return moveEntry(
        src, dest,
        isDirFi, errNotDirectory,
        os.RemoveAll,
        func(src, dest string) error { return copyDir(src, dest) })
}

// moveEntry moves source to target by renaming or copying.
func moveEntry(src, dest string, check funcCheckFileInfo, errMode error, remove funcRemoveEntry, copy funcCopyEntry) (err error) {
    // validate and refine paths
    if src, dest, err = refineOpPaths(opnMove, src, dest, false); err != nil {
        return
    }

    // check if source exists and its file mode
    var srcInfo os.FileInfo
    if srcInfo, err = os.Lstat(src); err == nil && !check(&srcInfo) {
        err = opError(opnMove, src, errMode)
    }
    if err != nil {
        return
    }

    // attempts to move file by renaming links
    if err = os.Rename(src, dest); os.IsExist(err) || isLinkErrorNotDirectory(err) {
        // remove destination if fails for its existence or not directory
        _ = remove(dest)
        err = os.Rename(src, dest)
    }

    switch {
    case err == nil:
        // pass if rename succeeds
    case isLinkErrorCrossDevice(err):
        // cross device move == remove dest + copy to dest + remove src
        // remove destination file, and ignore the non-existence error
        if err = remove(dest); err != nil && !os.IsNotExist(err) {
            err = opError(opnMove, dest, err)
            return
        }
        if err = copy(src, dest); err == nil {
            err = remove(src)
        }
    case os.IsNotExist(err):
        err = opError(opnMove, src, err)
    case os.IsExist(err):
        err = opError(opnMove, dest, err)
    }
    return
}