mirror of
https://github.com/golang/go
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b40df0fb21
This implements a standard way of describing source locations along with printing and parsing of those locations and conversion to and from the token.Pos forms. Change-Id: Ibb3df0a282bc2effb0fa8bd3a51bb0d281b2ffb1 Reviewed-on: https://go-review.googlesource.com/c/tools/+/163778 Run-TryBot: Ian Cottrell <iancottrell@google.com> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Rebecca Stambler <rstambler@golang.org>
115 lines
3.1 KiB
Go
115 lines
3.1 KiB
Go
// Copyright 2019 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package span
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import (
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"go/token"
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)
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// Range represents a source code range in token.Pos form.
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// It also carries the FileSet that produced the positions, so that it is
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// self contained.
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type Range struct {
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FileSet *token.FileSet
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Start token.Pos
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End token.Pos
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}
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// TokenConverter is a Converter backed by a token file set and file.
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// It uses the file set methods to work out determine the conversions which
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// make if fast and do not require the file contents.
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type TokenConverter struct {
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fset *token.FileSet
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file *token.File
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}
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// NewRange creates a new Range from a FileSet and two positions.
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// To represent a point pass a 0 as the end pos.
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func NewRange(fset *token.FileSet, start, end token.Pos) Range {
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return Range{
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FileSet: fset,
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Start: start,
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End: end,
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}
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}
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// NewTokenConverter returns an implementation of Coords and Offsets backed by a
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// token.File.
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func NewTokenConverter(fset *token.FileSet, f *token.File) *TokenConverter {
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return &TokenConverter{fset: fset, file: f}
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}
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// NewContentConverter returns an implementation of Coords and Offsets for the
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// given file content.
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func NewContentConverter(filename string, content []byte) Converter {
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fset := token.NewFileSet()
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f := fset.AddFile(filename, -1, len(content))
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f.SetLinesForContent(content)
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return &TokenConverter{fset: fset, file: f}
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}
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// IsPoint returns true if the range represents a single point.
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func (r Range) IsPoint() bool {
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return r.Start == r.End
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}
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// Span converts a Range to a Span that represents the Range.
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// It will fill in all the members of the Span, calculating the line and column
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// information.
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func (r Range) Span() Span {
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f := r.FileSet.File(r.Start)
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s := Span{URI: FileURI(f.Name())}
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s.Start.Offset = f.Offset(r.Start)
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if r.End.IsValid() {
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s.End.Offset = f.Offset(r.End)
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}
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converter := NewTokenConverter(r.FileSet, f)
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return s.CleanCoords(converter)
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}
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// Range converts a Span to a Range that represents the Span for the supplied
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// File.
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func (s Span) Range(converter *TokenConverter) Range {
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s = s.CleanOffset(converter)
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return Range{
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FileSet: converter.fset,
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Start: converter.file.Pos(s.Start.Offset),
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End: converter.file.Pos(s.End.Offset),
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}
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}
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func (l *TokenConverter) ToCoord(offset int) (int, int) {
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pos := l.file.Pos(offset)
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p := l.fset.Position(pos)
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return p.Line, p.Column
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}
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func (l *TokenConverter) ToOffset(line, col int) int {
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if line < 0 {
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// before the start of the file
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return -1
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}
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lineMax := l.file.LineCount() + 1
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if line > lineMax {
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// after the end of the file
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return -1
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} else if line == lineMax {
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if col > 1 {
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// after the end of the file
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return -1
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}
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// at the end of the file, allowing for a trailing eol
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return l.file.Size()
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}
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pos := lineStart(l.file, line)
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if !pos.IsValid() {
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return -1
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}
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// we assume that column is in bytes here, and that the first byte of a
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// line is at column 1
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pos += token.Pos(col - 1)
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return l.file.Offset(pos)
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}
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