vendor tsgo

tools/tsgo/internal/jsonrpc/baseproto.go

@@ -0,0 +1,99 @@
+package jsonrpc
+
+import (
+	"bufio"
+	"bytes"
+	"errors"
+	"fmt"
+	"io"
+	"strconv"
+)
+
+// Base protocol for JSON-RPC with Content-Length headers (as used by LSP).
+// https://microsoft.github.io/language-server-protocol/specifications/base/0.9/specification/
+
+var (
+	ErrInvalidHeader        = errors.New("jsonrpc: invalid header")
+	ErrInvalidContentLength = errors.New("jsonrpc: invalid content length")
+	ErrNoContentLength      = errors.New("jsonrpc: no content length")
+)
+
+// Reader reads JSON-RPC messages with Content-Length framing.
+type Reader struct {
+	r *bufio.Reader
+}
+
+// NewReader creates a new Reader.
+func NewReader(r io.Reader) *Reader {
+	return &Reader{
+		r: bufio.NewReader(r),
+	}
+}
+
+// Read reads the next message payload.
+func (r *Reader) Read() ([]byte, error) {
+	var contentLength int64
+
+	for {
+		line, err := r.r.ReadBytes('\n')
+		if err != nil {
+			if errors.Is(err, io.EOF) {
+				return nil, io.EOF
+			}
+			return nil, fmt.Errorf("jsonrpc: read header: %w", err)
+		}
+
+		if bytes.Equal(line, []byte("\r\n")) {
+			break
+		}
+
+		key, value, ok := bytes.Cut(line, []byte(":"))
+		if !ok {
+			return nil, fmt.Errorf("%w: %q", ErrInvalidHeader, line)
+		}
+
+		if bytes.Equal(key, []byte("Content-Length")) {
+			contentLength, err = strconv.ParseInt(string(bytes.TrimSpace(value)), 10, 64)
+			if err != nil {
+				return nil, fmt.Errorf("%w: parse error: %w", ErrInvalidContentLength, err)
+			}
+			if contentLength < 0 {
+				return nil, fmt.Errorf("%w: negative value %d", ErrInvalidContentLength, contentLength)
+			}
+		}
+	}
+
+	if contentLength <= 0 {
+		return nil, ErrNoContentLength
+	}
+
+	data := make([]byte, contentLength)
+	if _, err := io.ReadFull(r.r, data); err != nil {
+		return nil, fmt.Errorf("jsonrpc: read content: %w", err)
+	}
+
+	return data, nil
+}
+
+// Writer writes JSON-RPC messages with Content-Length framing.
+type Writer struct {
+	w *bufio.Writer
+}
+
+// NewWriter creates a new Writer.
+func NewWriter(w io.Writer) *Writer {
+	return &Writer{
+		w: bufio.NewWriter(w),
+	}
+}
+
+// Write writes a message payload with Content-Length header.
+func (w *Writer) Write(data []byte) error {
+	if _, err := fmt.Fprintf(w.w, "Content-Length: %d\r\n\r\n", len(data)); err != nil {
+		return err
+	}
+	if _, err := w.w.Write(data); err != nil {
+		return err
+	}
+	return w.w.Flush()
+}