mirror of
https://github.com/golang/go
synced 2024-09-30 16:18:35 -06:00
7af746645d
The current tests contain a bug in the priming of funnyString; the subslicing leaves the resulting content slice with a capacity greater than its length. This allowed a bug ToUTF16Column to sneak through where we were not using 0-based column as the offset within the line. Fix the priming of funnyString, and fix the implementation of ToUTF16Column. Change-Id: I2618878d85bba26f52f99a3fc136ad21fe198dfc Reviewed-on: https://go-review.googlesource.com/c/tools/+/174357 Reviewed-by: Ian Cottrell <iancottrell@google.com> Run-TryBot: Ian Cottrell <iancottrell@google.com>
88 lines
2.8 KiB
Go
88 lines
2.8 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 (
|
|
"fmt"
|
|
"unicode/utf16"
|
|
"unicode/utf8"
|
|
)
|
|
|
|
// ToUTF16Column calculates the utf16 column expressed by the point given the
|
|
// supplied file contents.
|
|
// This is used to convert from the native (always in bytes) column
|
|
// representation and the utf16 counts used by some editors.
|
|
func ToUTF16Column(p Point, content []byte) (int, error) {
|
|
if content == nil {
|
|
return -1, fmt.Errorf("ToUTF16Column: missing content")
|
|
}
|
|
if !p.HasPosition() {
|
|
return -1, fmt.Errorf("ToUTF16Column: point is missing position")
|
|
}
|
|
if !p.HasOffset() {
|
|
return -1, fmt.Errorf("ToUTF16Column: point is missing offset")
|
|
}
|
|
offset := p.Offset() // 0-based
|
|
colZero := p.Column() - 1 // 0-based
|
|
if colZero == 0 {
|
|
// 0-based column 0, so it must be chr 1
|
|
return 1, nil
|
|
}
|
|
// work out the offset at the start of the line using the column
|
|
lineOffset := offset - colZero
|
|
if lineOffset < 0 || offset > len(content) {
|
|
return -1, fmt.Errorf("ToUTF16Column: offsets %v-%v outside file contents (%v)", lineOffset, offset, len(content))
|
|
}
|
|
// Use the offset to pick out the line start.
|
|
// This cannot panic: offset > len(content) and lineOffset < offset.
|
|
start := content[lineOffset:]
|
|
|
|
// Now, truncate down to the supplied column.
|
|
start = start[:colZero]
|
|
// and count the number of utf16 characters
|
|
// in theory we could do this by hand more efficiently...
|
|
return len(utf16.Encode([]rune(string(start)))) + 1, nil
|
|
}
|
|
|
|
// FromUTF16Column advances the point by the utf16 character offset given the
|
|
// supplied line contents.
|
|
// This is used to convert from the utf16 counts used by some editors to the
|
|
// native (always in bytes) column representation.
|
|
func FromUTF16Column(p Point, chr int, content []byte) (Point, error) {
|
|
if !p.HasOffset() {
|
|
return Point{}, fmt.Errorf("FromUTF16Column: point is missing offset")
|
|
}
|
|
// if chr is 1 then no adjustment needed
|
|
if chr <= 1 {
|
|
return p, nil
|
|
}
|
|
if p.Offset() >= len(content) {
|
|
return p, fmt.Errorf("FromUTF16Column: offset (%v) greater than length of content (%v)", p.Offset(), len(content))
|
|
}
|
|
remains := content[p.Offset():]
|
|
// scan forward the specified number of characters
|
|
for count := 1; count < chr; count++ {
|
|
if len(remains) <= 0 {
|
|
return Point{}, fmt.Errorf("FromUTF16Column: chr goes beyond the content")
|
|
}
|
|
r, w := utf8.DecodeRune(remains)
|
|
if r == '\n' {
|
|
return Point{}, fmt.Errorf("FromUTF16Column: chr goes beyond the line")
|
|
}
|
|
remains = remains[w:]
|
|
if r >= 0x10000 {
|
|
// a two point rune
|
|
count++
|
|
// if we finished in a two point rune, do not advance past the first
|
|
if count >= chr {
|
|
break
|
|
}
|
|
}
|
|
p.v.Column += w
|
|
p.v.Offset += w
|
|
}
|
|
return p, nil
|
|
}
|