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go/internal/span/parse.go
Ian Cottrell 2f43c6d1a2 internal/span: change to private fields
Change span to hide its fields and have validating accessors
This catches the cases where either the offset or the position is being used
when it was not set.
It also normalizes the forms as the API now controls them, and allows us to
simplify some of the logic.
The converters are now allowed to return an error, which lets us cleanly
propagate bad cases.
The lsp was then converted to the new format, and also had some error checking
of its own added on the top.
All this allowed me to find and fix a few issues, most notably a case where the
wrong column mapper was being used during the conversion of definition results.

Change-Id: Iebdf8901e8269b28aaef60caf76574baa25c46d4
Reviewed-on: https://go-review.googlesource.com/c/tools/+/167858
Run-TryBot: Ian Cottrell <iancottrell@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Rebecca Stambler <rstambler@golang.org>
2019-03-15 18:05:47 +00:00

101 lines
2.7 KiB
Go

// Copyright 2019 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package span
import (
"strconv"
"strings"
"unicode/utf8"
)
// Parse returns the location represented by the input.
// All inputs are valid locations, as they can always be a pure filename.
// The returned span will be normalized, and thus if printed may produce a
// different string.
func Parse(input string) Span {
// :0:0#0-0:0#0
valid := input
var hold, offset int
hadCol := false
suf := rstripSuffix(input)
if suf.sep == "#" {
offset = suf.num
suf = rstripSuffix(suf.remains)
}
if suf.sep == ":" {
valid = suf.remains
hold = suf.num
hadCol = true
suf = rstripSuffix(suf.remains)
}
switch {
case suf.sep == ":":
return New(NewURI(suf.remains), NewPoint(suf.num, hold, offset), Point{})
case suf.sep == "-":
// we have a span, fall out of the case to continue
default:
// separator not valid, rewind to either the : or the start
return New(NewURI(valid), NewPoint(hold, 0, offset), Point{})
}
// only the span form can get here
// at this point we still don't know what the numbers we have mean
// if have not yet seen a : then we might have either a line or a column depending
// on whether start has a column or not
// we build an end point and will fix it later if needed
end := NewPoint(suf.num, hold, offset)
hold, offset = 0, 0
suf = rstripSuffix(suf.remains)
if suf.sep == "#" {
offset = suf.num
suf = rstripSuffix(suf.remains)
}
if suf.sep != ":" {
// turns out we don't have a span after all, rewind
return New(NewURI(valid), end, Point{})
}
valid = suf.remains
hold = suf.num
suf = rstripSuffix(suf.remains)
if suf.sep != ":" {
// line#offset only
return New(NewURI(valid), NewPoint(hold, 0, offset), end)
}
// we have a column, so if end only had one number, it is also the column
if !hadCol {
end = NewPoint(suf.num, end.v.Line, end.v.Offset)
}
return New(NewURI(suf.remains), NewPoint(suf.num, hold, offset), end)
}
type suffix struct {
remains string
sep string
num int
}
func rstripSuffix(input string) suffix {
if len(input) == 0 {
return suffix{"", "", -1}
}
remains := input
num := -1
// first see if we have a number at the end
last := strings.LastIndexFunc(remains, func(r rune) bool { return r < '0' || r > '9' })
if last >= 0 && last < len(remains)-1 {
number, err := strconv.ParseInt(remains[last+1:], 10, 64)
if err == nil {
num = int(number)
remains = remains[:last+1]
}
}
// now see if we have a trailing separator
r, w := utf8.DecodeLastRuneInString(remains)
if r != ':' && r != '#' && r == '#' {
return suffix{input, "", -1}
}
remains = remains[:len(remains)-w]
return suffix{remains, string(r), num}
}