func()

in internal/filesystem/filesystem.go [123:169]

• 39 lines of code
• 8 McCabe index (conditional complexity)

func (fs *fsystem) applyDocumentChange(buf *bytes.Buffer, change DocumentChange) error {
	// if the range is nil, we assume it is full content change
	if change.Range() == nil {
		buf.Reset()
		_, err := buf.WriteString(change.Text())
		return err
	}

	lines := source.MakeSourceLines("", buf.Bytes())

	startByte, err := ByteOffsetForPos(lines, change.Range().Start)
	if err != nil {
		return err
	}
	endByte, err := ByteOffsetForPos(lines, change.Range().End)
	if err != nil {
		return err
	}

	diff := endByte - startByte
	if diff > 0 {
		buf.Grow(diff)
	}

	beforeChange := make([]byte, startByte)
	copy(beforeChange, buf.Bytes())
	afterBytes := buf.Bytes()[endByte:]
	afterChange := make([]byte, len(afterBytes))
	copy(afterChange, afterBytes)

	buf.Reset()

	_, err = buf.Write(beforeChange)
	if err != nil {
		return err
	}
	_, err = buf.WriteString(change.Text())
	if err != nil {
		return err
	}
	_, err = buf.Write(afterChange)
	if err != nil {
		return err
	}

	return nil
}