78 lines
2.2 KiB
Go
78 lines
2.2 KiB
Go
package lsp
|
|
|
|
import (
|
|
"fmt"
|
|
"go/format"
|
|
"strings"
|
|
|
|
"golang.org/x/tools/internal/lsp/protocol"
|
|
)
|
|
|
|
// format formats a document with a given range.
|
|
func (s *server) format(uri protocol.DocumentURI, rng *protocol.Range) ([]protocol.TextEdit, error) {
|
|
data, err := s.readActiveFile(uri)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
if rng != nil {
|
|
start, err := positionToOffset(data, int(rng.Start.Line), int(rng.Start.Character))
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
end, err := positionToOffset(data, int(rng.End.Line), int(rng.End.Character))
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
data = data[start:end]
|
|
// format.Source will fail if the substring is not a balanced expression tree.
|
|
// TODO(rstambler): parse the file and use astutil.PathEnclosingInterval to
|
|
// find the largest ast.Node n contained within start:end, and format the
|
|
// region n.Pos-n.End instead.
|
|
}
|
|
// format.Source changes slightly from one release to another, so the version
|
|
// of Go used to build the LSP server will determine how it formats code.
|
|
// This should be acceptable for all users, who likely be prompted to rebuild
|
|
// the LSP server on each Go release.
|
|
fmted, err := format.Source([]byte(data))
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
if rng == nil {
|
|
// Get the ending line and column numbers for the original file.
|
|
line := strings.Count(data, "\n")
|
|
col := len(data) - strings.LastIndex(data, "\n") - 1
|
|
if col < 0 {
|
|
col = 0
|
|
}
|
|
rng = &protocol.Range{
|
|
Start: protocol.Position{0, 0},
|
|
End: protocol.Position{float64(line), float64(col)},
|
|
}
|
|
}
|
|
// TODO(rstambler): Compute text edits instead of replacing whole file.
|
|
return []protocol.TextEdit{
|
|
{
|
|
Range: *rng,
|
|
NewText: string(fmted),
|
|
},
|
|
}, nil
|
|
}
|
|
|
|
// positionToOffset converts a 0-based line and column number in a file
|
|
// to a byte offset value.
|
|
func positionToOffset(contents string, line, col int) (int, error) {
|
|
start := 0
|
|
for i := 0; i < int(line); i++ {
|
|
if start >= len(contents) {
|
|
return 0, fmt.Errorf("file contains %v lines, not %v lines", i, line)
|
|
}
|
|
index := strings.IndexByte(contents[start:], '\n')
|
|
if index == -1 {
|
|
return 0, fmt.Errorf("file contains %v lines, not %v lines", i, line)
|
|
}
|
|
start += (index + 1)
|
|
}
|
|
offset := start + int(col)
|
|
return offset, nil
|
|
}
|