forked from golang/tools
/
format.go
62 lines (58 loc) · 1.64 KB
/
format.go
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package lsp
import (
"context"
"go/token"
"golang.org/x/tools/internal/lsp/protocol"
"golang.org/x/tools/internal/lsp/source"
)
// formatRange formats a document with a given range.
func formatRange(ctx context.Context, v source.View, uri protocol.DocumentURI, rng *protocol.Range) ([]protocol.TextEdit, error) {
f, err := v.GetFile(ctx, fromProtocolURI(uri))
if err != nil {
return nil, err
}
tok, err := f.GetToken()
if err != nil {
return nil, err
}
var r source.Range
if rng == nil {
r.Start = tok.Pos(0)
r.End = tok.Pos(tok.Size())
} else {
r = fromProtocolRange(tok, *rng)
}
content, err := f.Read()
if err != nil {
return nil, err
}
edits, err := source.Format(ctx, f, r)
if err != nil {
return nil, err
}
return toProtocolEdits(tok, content, edits), nil
}
func toProtocolEdits(tok *token.File, content []byte, edits []source.TextEdit) []protocol.TextEdit {
if edits == nil {
return nil
}
// When a file ends with an empty line, the newline character is counted
// as part of the previous line. This causes the formatter to insert
// another unnecessary newline on each formatting. We handle this case by
// checking if the file already ends with a newline character.
hasExtraNewline := content[len(content)-1] == '\n'
result := make([]protocol.TextEdit, len(edits))
for i, edit := range edits {
rng := toProtocolRange(tok, edit.Range)
// If the edit ends at the end of the file, add the extra line.
if hasExtraNewline && tok.Offset(edit.Range.End) == len(content) {
rng.End.Line++
rng.End.Character = 0
}
result[i] = protocol.TextEdit{
Range: rng,
NewText: edit.NewText,
}
}
return result
}