textdiff

README

Text/diff

This is a copy of the Go text diffing package that gopls uses to generate unified diffs. There is some discussion about moving the package out of an internal package, but in the meantime this can be used.

This is identical to https://github.com/hexops/gotextdiff, but that hasn't been updated with the newer API, so I just did the same thing.

The code is entirely written by the Go Authors.

No PRs will be accepted here - please contribute to the upstream source!

License

See https://github.com/golang/tools/blob/master/LICENSE

Documentation

Overview

Package textdiff computes differences between text files or strings.

Index

• Constants
• func Apply(src string, edits []Edit) (string, error)
• func ApplyBytes(src []byte, edits []Edit) ([]byte, error)
• func SortEdits(edits []Edit)
• func ToUnified(oldLabel, newLabel, content string, edits []Edit, contextLines int) (string, error)
• func Unified(oldLabel, newLabel, old, new string) string
• type Edit
  • func Bytes(before, after []byte) []Edit
  • func Strings(before, after string) []Edit
  • func (e Edit) String() string

Constants

const DefaultContextLines = 3

DefaultContextLines is the number of unchanged lines of surrounding context displayed by Unified. Use ToUnified to specify a different value.

Functions

func Apply

func Apply(src string, edits []Edit) (string, error)

Apply applies a sequence of edits to the src buffer and returns the result. Edits are applied in order of start offset; edits with the same start offset are applied in they order they were provided.

Apply returns an error if any edit is out of bounds, or if any pair of edits is overlapping.

func ApplyBytes

func ApplyBytes(src []byte, edits []Edit) ([]byte, error)

ApplyBytes is like Apply, but it accepts a byte slice. The result is always a new array.

func SortEdits

func SortEdits(edits []Edit)

SortEdits orders a slice of Edits by (start, end) offset. This ordering puts insertions (end = start) before deletions (end > start) at the same point, but uses a stable sort to preserve the order of multiple insertions at the same point. (Apply detects multiple deletions at the same point as an error.)

func ToUnified

func ToUnified(oldLabel, newLabel, content string, edits []Edit, contextLines int) (string, error)

ToUnified applies the edits to content and returns a unified diff, with contextLines lines of (unchanged) context around each diff hunk. The old and new labels are the names of the content and result files. It returns an error if the edits are inconsistent; see ApplyEdits.

func Unified

func Unified(oldLabel, newLabel, old, new string) string

Unified returns a unified diff of the old and new strings. The old and new labels are the names of the old and new files. If the strings are equal, it returns the empty string.

Types

type Edit

type Edit struct {
	Start, End int    // byte offsets of the region to replace
	New        string // the replacement
}

An Edit describes the replacement of a portion of a text file.

func Bytes

func Bytes(before, after []byte) []Edit

Bytes computes the differences between two byte slices. The resulting edits respect rune boundaries.

func Strings

func Strings(before, after string) []Edit

Strings computes the differences between two strings. The resulting edits respect rune boundaries.

func (Edit) String

func (e Edit) String() string