1set/gut

package yos

import (
    "os"
    "path/filepath"
    "regexp"
    "strings"
)

// A FilePathInfo describes path and stat of a file or directory.
type FilePathInfo struct {
    Path string
    Info os.FileInfo
}

// ListAll returns a list of all entries in the given directory in lexical order. The given directory is not included in the list.
//
// It searches recursively, but symbolic links other than the given path will be not be followed.
func ListAll(root string) (entries []*FilePathInfo, err error) {
    return listCondEntries(root, func(info os.FileInfo) (bool, error) { return true, nil })
}

// ListFile returns a list of file entries in the given directory in lexical order. The given directory is not included in the list.
//
// It searches recursively, but symbolic links other than the given path will be not be followed.
func ListFile(root string) (entries []*FilePathInfo, err error) {
    return listCondEntries(root, func(info os.FileInfo) (bool, error) { return isFileFi(&info), nil })
}

// ListSymlink returns a list of symbolic link entries in the given directory in lexical order. The given directory is not included in the list.
//
// It searches recursively, but symbolic links other than the given path will be not be followed.
func ListSymlink(root string) (entries []*FilePathInfo, err error) {
    return listCondEntries(root, func(info os.FileInfo) (bool, error) { return isSymlinkFi(&info), nil })
}

// ListDir returns a list of nested directory entries in the given directory in lexical order. The given directory is not included in the list.
//
// It searches recursively, but symbolic links other than the given path will be not be followed.
func ListDir(root string) (entries []*FilePathInfo, err error) {
    return listCondEntries(root, func(info os.FileInfo) (bool, error) { return isDirFi(&info), nil })
}

// The flags are used by the ListMatch method.
const (
    // ListRecursive indicates ListMatch to recursively list directory entries encountered.
    ListRecursive int = 1 << iota
    // ListToLower indicates ListMatch to convert file name to lower case before the pattern matching.
    ListToLower
    // ListUseRegExp indicates ListMatch to use regular expression for the pattern matching.
    ListUseRegExp
    // ListIncludeDir indicates ListMatch to include matched directories in the returned list.
    ListIncludeDir
    // ListIncludeFile indicates ListMatch to include matched files in the returned list.
    ListIncludeFile
    // ListIncludeSymlink indicates ListMatch to include matched symbolic link in the returned list.
    ListIncludeSymlink
)

const (
    // ListIncludeAll indicates ListMatch to include all the matched in the returned list.
    ListIncludeAll = ListIncludeDir | ListIncludeFile | ListIncludeSymlink
)

// ListMatch returns a list of directory entries that matches any given pattern in the directory in lexical order.
//
// Symbolic links other than the given path will be not be followed. The given directory is not included in the list.
//
// ListMatch requires the pattern to match the full file name, not just a substring. Errors are returned if any pattern is malformed.
//
// There are two types of patterns are supported:
//   1) wildcard described in filepath.Match(), this is default;
//   2) regular expression accepted by google/RE2, use the ListUseRegExp flag to enable;
func ListMatch(root string, flag int, patterns ...string) (entries []*FilePathInfo, err error) {
    var (
        rePatterns   []*regexp.Regexp
        typeFlag     = flag & ListIncludeAll
        useRegExp    = flag&ListUseRegExp != 0
        useLowerName = flag&ListToLower != 0
    )
    if useRegExp {
        if rePatterns, err = compileRegexpList(patterns); err != nil {
            return
        }
    }

    return listCondEntries(root, func(info os.FileInfo) (ok bool, err error) {
        fileName := info.Name()
        if useLowerName {
            fileName = strings.ToLower(fileName)
        }

        if isFileTypeMatched(&info, typeFlag) {
            if useRegExp {
                for _, pat := range rePatterns {
                    if ok = pat.MatchString(fileName); ok {
                        break
                    }
                }
            } else {
                for _, pat := range patterns {
                    if ok, err = filepath.Match(pat, fileName); ok || err != nil {
                        break
                    }
                }
            }
        }

        if err == nil && (flag&ListRecursive == 0) && isDirFi(&info) {
            err = filepath.SkipDir
        }
        return
    })
}

// listCondEntries returns a list of conditional directory entries.
func listCondEntries(root string, cond func(os.FileInfo) (bool, error)) (entries []*FilePathInfo, err error) {
    var (
        rootFi   os.FileInfo
        rootPath string
    )
    if rootPath, rootFi, err = resolveDirInfo(root); err != nil {
        err = opError(opnList, root, err)
        return
    }

    err = filepath.Walk(rootPath, func(itemPath string, itemFi os.FileInfo, errIn error) (errOut error) {
        errOut = errIn
        if os.SameFile(rootFi, itemFi) || errOut != nil {
            return
        }
        var ok bool
        if ok, errOut = cond(itemFi); ok {
            entries = append(entries, &FilePathInfo{
                Path: itemPath,
                Info: itemFi,
            })
        }
        return
    })
    return
}

// isFileTypeMatched checks whether the file type is matched with the flag.
func isFileTypeMatched(info *os.FileInfo, flag int) (match bool) {
    switch {
    case flag == ListIncludeAll:
        match = true
    case flag&ListIncludeDir != 0 && isDirFi(info):
        match = true
    case flag&ListIncludeFile != 0 && isFileFi(info):
        match = true
    case flag&ListIncludeSymlink != 0 && isSymlinkFi(info):
        match = true
    }
    return
}