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// Copyright 2020 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 fake
import (
"fmt"
"sort"
"strings"
"golang.org/x/tools/internal/lsp/protocol"
)
// Pos represents a position in a text buffer. Both Line and Column are
// 0-indexed.
type Pos struct {
Line, Column int
}
// Range corresponds to protocol.Range, but uses the editor friend Pos
// instead of UTF-16 oriented protocol.Position
type Range struct {
Start Pos
End Pos
}
func (p Pos) ToProtocolPosition() protocol.Position {
return protocol.Position{
Line: float64(p.Line),
Character: float64(p.Column),
}
}
func fromProtocolPosition(pos protocol.Position) Pos {
return Pos{
Line: int(pos.Line),
Column: int(pos.Character),
}
}
// Edit represents a single (contiguous) buffer edit.
type Edit struct {
Start, End Pos
Text string
}
// Location is the editor friendly equivalent of protocol.Location
type Location struct {
Path string
Range Range
}
// SymbolInformation is an editor friendly version of
// protocol.SymbolInformation, with location information transformed to byte
// offsets. Field names correspond to the protocol type.
type SymbolInformation struct {
Name string
Kind protocol.SymbolKind
Location Location
}
// NewEdit creates an edit replacing all content between
// (startLine, startColumn) and (endLine, endColumn) with text.
func NewEdit(startLine, startColumn, endLine, endColumn int, text string) Edit {
return Edit{
Start: Pos{Line: startLine, Column: startColumn},
End: Pos{Line: endLine, Column: endColumn},
Text: text,
}
}
func (e Edit) toProtocolChangeEvent() protocol.TextDocumentContentChangeEvent {
return protocol.TextDocumentContentChangeEvent{
Range: &protocol.Range{
Start: e.Start.ToProtocolPosition(),
End: e.End.ToProtocolPosition(),
},
Text: e.Text,
}
}
func fromProtocolTextEdit(textEdit protocol.TextEdit) Edit {
return Edit{
Start: fromProtocolPosition(textEdit.Range.Start),
End: fromProtocolPosition(textEdit.Range.End),
Text: textEdit.NewText,
}
}
// inText reports whether p is a valid position in the text buffer.
func inText(p Pos, content []string) bool {
if p.Line < 0 || p.Line >= len(content) {
return false
}
// Note the strict right bound: the column indexes character _separators_,
// not characters.
if p.Column < 0 || p.Column > len([]rune(content[p.Line])) {
return false
}
return true
}
// editContent implements a simplistic, inefficient algorithm for applying text
// edits to our buffer representation. It returns an error if the edit is
// invalid for the current content.
func editContent(content []string, edits []Edit) ([]string, error) {
newEdits := make([]Edit, len(edits))
copy(newEdits, edits)
sort.Slice(newEdits, func(i, j int) bool {
if newEdits[i].Start.Line < newEdits[j].Start.Line {
return true
}
if newEdits[i].Start.Line > newEdits[j].Start.Line {
return false
}
return newEdits[i].Start.Column < newEdits[j].Start.Column
})
// Validate edits.
for _, edit := range newEdits {
if edit.End.Line < edit.Start.Line || (edit.End.Line == edit.Start.Line && edit.End.Column < edit.Start.Column) {
return nil, fmt.Errorf("invalid edit: end %v before start %v", edit.End, edit.Start)
}
if !inText(edit.Start, content) {
return nil, fmt.Errorf("start position %v is out of bounds", edit.Start)
}
if !inText(edit.End, content) {
return nil, fmt.Errorf("end position %v is out of bounds", edit.End)
}
}
var (
b strings.Builder
line, column int
)
advance := func(toLine, toColumn int) {
for ; line < toLine; line++ {
b.WriteString(string([]rune(content[line])[column:]) + "\n")
column = 0
}
b.WriteString(string([]rune(content[line])[column:toColumn]))
column = toColumn
}
for _, edit := range newEdits {
advance(edit.Start.Line, edit.Start.Column)
b.WriteString(edit.Text)
line = edit.End.Line
column = edit.End.Column
}
advance(len(content)-1, len([]rune(content[len(content)-1])))
return strings.Split(b.String(), "\n"), nil
}