pathtype

README

pathtype

Add a type for paths in Go. This small package basically just wraps "path/filepath" from the Standard library.

Example

Code

package main

import (
	"fmt"
	"log"

	pt "github.com/jonchun/pathtype"
)

type path = pt.Path

func main() {
	myFile := path("myfile.txt")
	exampleFile := path("example/example.txt")
	fmt.Println(exampleFile.Dir())
	fmt.Println(exampleFile.Dir().Join(myFile))

	res, err := exampleFile.Dir().Join(myFile).Dir().Abs()
	if err != nil {
		log.Fatal(err)
	}
	fmt.Println(res)

	fmt.Println("=========================")
	listBase(res)
	fmt.Println("=========================")
	listExt(res)
}

// list all Base for files in p
func listBase(p path) {
	if glob, err := p.Glob("*"); err != nil {
		log.Fatal(err)
	} else {
		for _, match := range glob {
			fmt.Println(match.Base())
		}
	}
}

// list all extensions for files in p
func listExt(p path) {
	if glob, err := p.Glob("*"); err != nil {
		log.Fatal(err)
	} else {
		for _, match := range glob {
			fmt.Println(match.Ext())
		}
	}
}

Output

example
example/myfile.txt
/home/jonchun/example_module/example
=========================
1.log
2.log
example.txt
=========================
.log
.log
.txt

See GoDoc for documentation, but it should be pretty self-explanatory.

TODO

• Add wrappers for other packages that take paths as strings. e.g: os Would be nice to have syntax similar to

  import pt "github.com/jonchun/pathtype"
  type path = pt.Path
  
  func example(p path) {
      pt.Chmod(p, 0644)
  }
  

Documentation

Overview

This is a small wrapper around the filepath API that allows using file paths as their own type

Index

• type Path
  • func SplitList(path string) []Path
  • func (path Path) Abs() (Path, error)
  • func (path Path) Base() Path
  • func (path Path) Clean() Path
  • func (path Path) Dir() Path
  • func (path Path) EvalSymlinks() (Path, error)
  • func (path Path) Ext() string
  • func (path Path) FromSlash() Path
  • func (path Path) Glob(pattern string) (matches []Path, err error)
  • func (path Path) IsAbs() bool
  • func (path Path) Join(elem ...Path) Path
  • func (path Path) Match(pattern string) (bool, error)
  • func (path Path) Rel(targpath Path) (Path, error)
  • func (path Path) Split() (dir, file Path)
  • func (path Path) ToSlash() Path
  • func (path Path) VolumeName() Path
  • func (path Path) Walk(fn filepath.WalkFunc) error
  • func (path Path) WalkDir(fn fs.WalkDirFunc) error

Examples

• Path.Base
• Path.Dir
• Path.Ext
• Path.IsAbs
• Path.Join
• Path.Match
• Path.Rel
• Path.Split
• SplitList

Types

type Path

type Path string

func SplitList

func SplitList(path string) []Path

SplitList splits a list of paths joined by the OS-specific ListSeparator, usually found in PATH or GOPATH environment variables. Unlike strings.Split, SplitList returns an empty slice when passed an empty string.

Example

package main

import (
	"fmt"

	pt "github.com/jonchun/pathtype"
)

func main() {
	fmt.Println("On Unix:", pt.SplitList("/a/b/c:/usr/bin"))
}

Output:

On Unix: [/a/b/c /usr/bin]

func (Path) Abs

func (path Path) Abs() (Path, error)

Abs returns an absolute representation of path. If the path is not absolute it will be joined with the current working directory to turn it into an absolute path. The absolute path name for a given file is not guaranteed to be unique. Abs calls Clean on the result.

func (Path) Base

func (path Path) Base() Path

Base returns the last element of path. Trailing path separators are removed before extracting the last element. If the path is empty, Base returns ".". If the path consists entirely of separators, Base returns a single separator.

Example

package main

import (
	"fmt"

	pt "github.com/jonchun/pathtype"
)

func main() {
	type path = pt.Path
	fmt.Println("On Unix:")
	fmt.Println(path("/foo/bar/baz.js").Base())
	fmt.Println(path("/foo/bar/baz").Base())
	fmt.Println(path("/foo/bar/baz/").Base())
	fmt.Println(path("dev.txt").Base())
	fmt.Println(path("../todo.txt").Base())
	fmt.Println(path("..").Base())
	fmt.Println(path(".").Base())
	fmt.Println(path("/").Base())
	fmt.Println(path("").Base())

}

Output:

On Unix:
baz.js
baz
baz
dev.txt
todo.txt
..
.
/
.

func (Path) Clean

func (path Path) Clean() Path

Clean returns the shortest path name equivalent to path by purely lexical processing. It applies the following rules iteratively until no further processing can be done:

1. Replace multiple Separator elements with a single one.
2. Eliminate each . path name element (the current directory).
3. Eliminate each inner .. path name element (the parent directory) along with the non-.. element that precedes it.
4. Eliminate .. elements that begin a rooted path: that is, replace "/.." by "/" at the beginning of a path, assuming Separator is '/'.

The returned path ends in a slash only if it represents a root directory, such as "/" on Unix or `C:\` on Windows.

Finally, any occurrences of slash are replaced by Separator.

If the result of this process is an empty string, Clean returns the string ".".

See also Rob Pike, “Lexical File Names in Plan 9 or Getting Dot-Dot Right,” https://9p.io/sys/doc/lexnames.html

func (Path) Dir

func (path Path) Dir() Path

Dir returns all but the last element of path, typically the path's directory. After dropping the final element, Dir calls Clean on the path and trailing slashes are removed. If the path is empty, Dir returns ".". If the path consists entirely of separators, Dir returns a single separator. The returned path does not end in a separator unless it is the root directory.

Example

package main

import (
	"fmt"

	pt "github.com/jonchun/pathtype"
)

func main() {
	type path = pt.Path
	fmt.Println("On Unix:")
	fmt.Println(path("/foo/bar/baz.js").Dir())
	fmt.Println(path("/foo/bar/baz").Dir())
	fmt.Println(path("/foo/bar/baz/").Dir())
	fmt.Println(path("/dirty//path///").Dir())
	fmt.Println(path("dev.txt").Dir())
	fmt.Println(path("../todo.txt").Dir())
	fmt.Println(path("..").Dir())
	fmt.Println(path(".").Dir())
	fmt.Println(path("/").Dir())
	fmt.Println(path("").Dir())

}

Output:

On Unix:
/foo/bar
/foo/bar
/foo/bar/baz
/dirty/path
.
..
.
.
/
.

func (Path) EvalSymlinks

func (path Path) EvalSymlinks() (Path, error)

EvalSymlinks returns path's name after the evaluation of any symbolic links. If path is relative the result will be relative to the current directory, unless one of the components is an absolute symbolic link. EvalSymlinks calls Clean on the result.

func (Path) Ext

func (path Path) Ext() string

Ext returns the file name extension used by path. The extension is the suffix beginning at the final dot in the final element of path; it is empty if there is no dot.

Example

package main

import (
	"fmt"

	pt "github.com/jonchun/pathtype"
)

func main() {
	type path = pt.Path
	fmt.Printf("No dots: %q\n", path("index").Ext())
	fmt.Printf("One dot: %q\n", path("index.js").Ext())
	fmt.Printf("Two dots: %q\n", path("main.test.js").Ext())
}

Output:

No dots: ""
One dot: ".js"
Two dots: ".js"

func (Path) FromSlash

func (path Path) FromSlash() Path

FromSlash returns the result of replacing each slash ('/') character in path with a separator character. Multiple slashes are replaced by multiple separators.

func (Path) Glob

func (path Path) Glob(pattern string) (matches []Path, err error)

Glob returns the names of all files matching pattern or nil if there is no matching file. The syntax of patterns is the same as in Match. The pattern may describe hierarchical names such as /usr/*/bin/ed (assuming the Separator is '/').

Glob ignores file system errors such as I/O errors reading directories. The only possible returned error is ErrBadPattern, when pattern is malformed.

func (Path) IsAbs

func (path Path) IsAbs() bool

IsAbs reports whether the path is absolute.

Example

package main

import (
	"fmt"

	pt "github.com/jonchun/pathtype"
)

func main() {
	type path = pt.Path
	fmt.Println("On Unix:")
	fmt.Println(path("/home/gopher").IsAbs())
	fmt.Println(path(".bashrc").IsAbs())
	fmt.Println(path("..").IsAbs())
	fmt.Println(path(".").IsAbs())
	fmt.Println(path("/").IsAbs())
	fmt.Println(path("").IsAbs())

}

Output:

On Unix:
true
false
false
false
true
false

func (Path) Join

func (path Path) Join(elem ...Path) Path

Join joins any number of path elements into path, separating them with an OS specific Separator. Empty elements are ignored. The result is Cleaned. However, if the argument list is empty or all its elements are empty, Join returns an empty string. On Windows, the result will only be a UNC path if the first non-empty element is a UNC path.

Example

package main

import (
	"fmt"

	pt "github.com/jonchun/pathtype"
)

func main() {
	type path = pt.Path
	fmt.Println("On Unix:")
	fmt.Println(path("a").Join(path("b"), path("c")))
	fmt.Println(path("a").Join(path("b/c")))
	fmt.Println(path("a/b").Join(path("c")))
	fmt.Println(path("a/b").Join(path("/c")))

	fmt.Println(path("a/b").Join(path("../../../xyz")))

}

Output:

On Unix:
a/b/c
a/b/c
a/b/c
a/b/c
../xyz

func (Path) Match

func (path Path) Match(pattern string) (bool, error)

Match reports whether the path matches the shell file name pattern. The pattern syntax is:

pattern:
	{ term }
term:
	'*'         matches any sequence of non-Separator characters
	'?'         matches any single non-Separator character
	'[' [ '^' ] { character-range } ']'
	            character class (must be non-empty)
	c           matches character c (c != '*', '?', '\\', '[')
	'\\' c      matches character c

character-range:
	c           matches character c (c != '\\', '-', ']')
	'\\' c      matches character c
	lo '-' hi   matches character c for lo <= c <= hi

Match requires pattern to match all of name, not just a substring. The only possible returned error is ErrBadPattern, when pattern is malformed.

On Windows, escaping is disabled. Instead, '\\' is treated as path separator.

Example

package main

import (
	"fmt"

	pt "github.com/jonchun/pathtype"
)

func main() {
	type path = pt.Path
	fmt.Println("On Unix:")
	fmt.Println(path("/home/catch/foo").Match("/home/catch/*"))
	fmt.Println(path("/home/catch/foo/bar").Match("/home/catch/*"))
	fmt.Println(path("/home/gopher").Match("/home/?opher"))
	fmt.Println(path("/home/*").Match("/home/\\*"))

}

Output:

On Unix:
true <nil>
false <nil>
true <nil>
true <nil>

func (Path) Rel

func (path Path) Rel(targpath Path) (Path, error)

Rel returns a relative path that is lexically equivalent to targpath when joined to path with an intervening separator. That is, path.Join(path.Rel(targpath)) is equivalent to targpath itself. On success, the returned path will always be relative to path, even if path and targpath share no elements. An error is returned if targpath can't be made relative to path or if knowing the current working directory would be necessary to compute it. Rel calls Clean on the result.

Example

package main

import (
	"fmt"

	pt "github.com/jonchun/pathtype"
)

func main() {
	type path = pt.Path

	paths := []path{
		path("/a/b/c"),
		path("/b/c"),
		path("./b/c"),
	}
	base := path("/a")

	fmt.Println("On Unix:")
	for _, p := range paths {
		rel, err := base.Rel(p)
		fmt.Printf("%q: %q %v\n", p, rel, err)
	}

}

Output:

On Unix:
"/a/b/c": "b/c" <nil>
"/b/c": "../b/c" <nil>
"./b/c": "" Rel: can't make ./b/c relative to /a

func (Path) Split

func (path Path) Split() (dir, file Path)

Split splits the path immediately following the final Separator, separating it into a directory and file name component. If there is no Separator in path, Split returns an empty dir and file set to path. The returned values have the property that path = dir+file.

Example

package main

import (
	"fmt"

	pt "github.com/jonchun/pathtype"
)

func main() {
	type path = pt.Path

	paths := []path{
		path("/home/arnie/amelia.jpg"),
		path("/mnt/photos/"),
		path("rabbit.jpg"),
		path("/usr/local//go"),
	}
	fmt.Println("On Unix:")
	for _, p := range paths {
		dir, file := p.Split()
		fmt.Printf("input: %q\n\tdir: %q\n\tfile: %q\n", p, dir, file)
	}
}

Output:

On Unix:
input: "/home/arnie/amelia.jpg"
	dir: "/home/arnie/"
	file: "amelia.jpg"
input: "/mnt/photos/"
	dir: "/mnt/photos/"
	file: ""
input: "rabbit.jpg"
	dir: ""
	file: "rabbit.jpg"
input: "/usr/local//go"
	dir: "/usr/local//"
	file: "go"

func (Path) ToSlash

func (path Path) ToSlash() Path

ToSlash returns the result of replacing each separator character in path with a slash ('/') character. Multiple separators are replaced by multiple slashes.

func (Path) VolumeName

func (path Path) VolumeName() Path

VolumeName returns leading volume name. Given "C:\foo\bar" it returns "C:" on Windows. Given "\\host\share\foo" it returns "\\host\share". On other platforms it returns "".

func (Path) Walk

func (path Path) Walk(fn filepath.WalkFunc) error

Walk walks the file tree rooted at path, calling fn for each file or directory in the tree, including path.

All errors that arise visiting files and directories are filtered by fn: see the WalkFunc documentation for details.

The files are walked in lexical order, which makes the output deterministic but requires Walk to read an entire directory into memory before proceeding to walk that directory.

Walk does not follow symbolic links.

Walk is less efficient than WalkDir, introduced in Go 1.16, which avoids calling os.Lstat on every visited file or directory.

func (Path) WalkDir

func (path Path) WalkDir(fn fs.WalkDirFunc) error

WalkDir walks the file tree rooted at path, calling fn for each file or directory in the tree, including path.

All errors that arise visiting files and directories are filtered by fn: see the fs.WalkDirFunc documentation for details.

The files are walked in lexical order, which makes the output deterministic but requires WalkDir to read an entire directory into memory before proceeding to walk that directory.

WalkDir does not follow symbolic links.