rclone/fs/fspath/path.go

342 lines
9.9 KiB
Go

// Package fspath contains routines for fspath manipulation
package fspath
import (
"errors"
"path"
"path/filepath"
"regexp"
"strings"
"github.com/rclone/rclone/fs/config/configmap"
"github.com/rclone/rclone/fs/driveletter"
)
const (
configNameRe = `[\w. -]+`
remoteNameRe = `^(:?` + configNameRe + `)`
)
var (
errInvalidCharacters = errors.New("config name contains invalid characters - may only contain `0-9`, `A-Z`, `a-z`, `_`, `-`, `.` and space")
errCantBeEmpty = errors.New("can't use empty string as a path")
errCantStartWithDash = errors.New("config name starts with `-`")
errBadConfigParam = errors.New("config parameters may only contain `0-9`, `A-Z`, `a-z` and `_`")
errEmptyConfigParam = errors.New("config parameters can't be empty")
errConfigNameEmpty = errors.New("config name can't be empty")
errConfigName = errors.New("config name needs a trailing `:`")
errParam = errors.New("config parameter must end with `,` or `:`")
errValue = errors.New("unquoted config value must end with `,` or `:`")
errQuotedValue = errors.New("unterminated quoted config value")
errAfterQuote = errors.New("expecting `:` or `,` or another quote after a quote")
errSyntax = errors.New("syntax error in config string")
// configNameMatcher is a pattern to match an rclone config name
configNameMatcher = regexp.MustCompile(`^` + configNameRe + `$`)
// remoteNameMatcher is a pattern to match an rclone remote name at the start of a config
remoteNameMatcher = regexp.MustCompile(`^` + remoteNameRe + `(:$|,)`)
)
// CheckConfigName returns an error if configName is invalid
func CheckConfigName(configName string) error {
if !configNameMatcher.MatchString(configName) {
return errInvalidCharacters
}
// Reject configName, if it starts with -, complicates usage. (#4261)
if strings.HasPrefix(configName, "-") {
return errCantStartWithDash
}
return nil
}
// checkRemoteName returns an error if remoteName is invalid
func checkRemoteName(remoteName string) error {
if remoteName == ":" || remoteName == "::" {
return errConfigNameEmpty
}
if !remoteNameMatcher.MatchString(remoteName) {
return errInvalidCharacters
}
return nil
}
// Return true if c is a valid character for a config parameter
func isConfigParam(c rune) bool {
return ((c >= 'a' && c <= 'z') ||
(c >= 'A' && c <= 'Z') ||
(c >= '0' && c <= '9') ||
c == '_')
}
// Parsed is returned from Parse with the results of the connection string decomposition
//
// If Name is "" then it is a local path in Path
//
// Note that ConfigString + ":" + Path is equal to the input of Parse except that Path may have had
// \ converted to /
type Parsed struct {
Name string // Just the name of the config: "remote" or ":backend"
ConfigString string // The whole config string: "remote:" or ":backend,value=6:"
Path string // The file system path, may be empty
Config configmap.Simple // key/value config parsed out of ConfigString may be nil
}
// Parse deconstructs a path into a Parsed structure
//
// If the path is a local path then parsed.Name will be returned as "".
//
// So "remote:path/to/dir" will return Parsed{Name:"remote", Path:"path/to/dir"},
// and "/path/to/local" will return Parsed{Name:"", Path:"/path/to/local"}
//
// Note that this will turn \ into / in the fsPath on Windows
//
// An error may be returned if the remote name has invalid characters or the
// parameters are invalid or the path is empty.
func Parse(path string) (parsed Parsed, err error) {
parsed.Path = filepath.ToSlash(path)
if path == "" {
return parsed, errCantBeEmpty
}
// If path has no `:` in, it must be a local path
if !strings.ContainsRune(path, ':') {
return parsed, nil
}
// States for parser
const (
stateConfigName = uint8(iota)
stateParam
stateValue
stateQuotedValue
stateAfterQuote
stateDone
)
var (
state = stateConfigName // current state of parser
i int // position in path
prev int // previous position in path
c rune // current rune under consideration
quote rune // kind of quote to end this quoted string
param string // current parameter value
doubled bool // set if had doubled quotes
)
loop:
for i, c = range path {
// Example Parse
// remote,param=value,param2="qvalue":/path/to/file
switch state {
// Parses "remote,"
case stateConfigName:
if i == 0 && c == ':' {
continue
} else if c == '/' || c == '\\' {
// `:` or `,` not before a path separator must be a local path,
// except if the path started with `:` in which case it was intended
// to be an on the fly remote so return an error.
if path[0] == ':' {
return parsed, errInvalidCharacters
}
return parsed, nil
} else if c == ':' || c == ',' {
parsed.Name = path[:i]
err := checkRemoteName(parsed.Name + ":")
if err != nil {
return parsed, err
}
prev = i + 1
if c == ':' {
// If we parsed a drive letter, must be a local path
if driveletter.IsDriveLetter(parsed.Name) {
parsed.Name = ""
return parsed, nil
}
state = stateDone
break loop
}
state = stateParam
parsed.Config = make(configmap.Simple)
}
// Parses param= and param2=
case stateParam:
if c == ':' || c == ',' || c == '=' {
param = path[prev:i]
if len(param) == 0 {
return parsed, errEmptyConfigParam
}
prev = i + 1
if c == '=' {
state = stateValue
break
}
parsed.Config[param] = "true"
if c == ':' {
state = stateDone
break loop
}
state = stateParam
} else if !isConfigParam(c) {
return parsed, errBadConfigParam
}
// Parses value
case stateValue:
if c == '\'' || c == '"' {
if i == prev {
quote = c
state = stateQuotedValue
prev = i + 1
doubled = false
break
}
} else if c == ':' || c == ',' {
value := path[prev:i]
prev = i + 1
parsed.Config[param] = value
if c == ':' {
state = stateDone
break loop
}
state = stateParam
}
// Parses "qvalue"
case stateQuotedValue:
if c == quote {
state = stateAfterQuote
}
// Parses : or , or quote after "qvalue"
case stateAfterQuote:
if c == ':' || c == ',' {
value := path[prev : i-1]
// replace any doubled quotes if there were any
if doubled {
value = strings.ReplaceAll(value, string(quote)+string(quote), string(quote))
}
prev = i + 1
parsed.Config[param] = value
if c == ':' {
state = stateDone
break loop
} else {
state = stateParam
}
} else if c == quote {
// Here is a doubled quote to indicate a literal quote
state = stateQuotedValue
doubled = true
} else {
return parsed, errAfterQuote
}
}
}
// Depending on which state we were in when we fell off the
// end of the state machine we can return a sensible error.
switch state {
default:
return parsed, errSyntax
case stateConfigName:
return parsed, errConfigName
case stateParam:
return parsed, errParam
case stateValue:
return parsed, errValue
case stateQuotedValue:
return parsed, errQuotedValue
case stateAfterQuote:
return parsed, errAfterQuote
case stateDone:
break
}
parsed.ConfigString = path[:i]
parsed.Path = path[i+1:]
// change native directory separators to / if there are any
parsed.Path = filepath.ToSlash(parsed.Path)
return parsed, nil
}
// SplitFs splits a remote a remoteName and an remotePath.
//
// SplitFs("remote:path/to/file") -> ("remote:", "path/to/file")
// SplitFs("/to/file") -> ("", "/to/file")
//
// If it returns remoteName as "" then remotePath is a local path
//
// The returned values have the property that remoteName + remotePath ==
// remote (except under Windows where \ will be translated into /)
func SplitFs(remote string) (remoteName string, remotePath string, err error) {
parsed, err := Parse(remote)
if err != nil {
return "", "", err
}
remoteName, remotePath = parsed.ConfigString, parsed.Path
if remoteName != "" {
remoteName += ":"
}
return remoteName, remotePath, nil
}
// Split splits a remote into a parent and a leaf
//
// if it returns leaf as an empty string then remote is a directory
//
// if it returns parent as an empty string then that means the current directory
//
// The returned values have the property that parent + leaf == remote
// (except under Windows where \ will be translated into /)
func Split(remote string) (parent string, leaf string, err error) {
remoteName, remotePath, err := SplitFs(remote)
if err != nil {
return "", "", err
}
// Construct new remote name without last segment
parent, leaf = path.Split(remotePath)
return remoteName + parent, leaf, nil
}
// Make filePath absolute so it can't read above the root
func makeAbsolute(filePath string) string {
leadingSlash := strings.HasPrefix(filePath, "/")
filePath = path.Join("/", filePath)
if !leadingSlash && strings.HasPrefix(filePath, "/") {
filePath = filePath[1:]
}
return filePath
}
// JoinRootPath joins filePath onto remote
//
// If the remote has a leading "//" this is preserved to allow Windows
// network paths to be used as remotes.
//
// If filePath is empty then remote will be returned.
//
// If the path contains \ these will be converted to / on Windows.
func JoinRootPath(remote, filePath string) string {
remote = filepath.ToSlash(remote)
if filePath == "" {
return remote
}
filePath = filepath.ToSlash(filePath)
filePath = makeAbsolute(filePath)
if strings.HasPrefix(remote, "//") {
return "/" + path.Join(remote, filePath)
}
parsed, err := Parse(remote)
remoteName, remotePath := parsed.ConfigString, parsed.Path
if err != nil {
// Couldn't parse so assume it is a path
remoteName = ""
remotePath = remote
}
remotePath = path.Join(remotePath, filePath)
if remoteName != "" {
remoteName += ":"
// if have remote: then normalise the remotePath
if remotePath == "." {
remotePath = ""
}
}
return remoteName + remotePath
}