New daemon architecture

internal/ipc/jsonl.go

@@ -0,0 +1,55 @@
+package ipc
+
+import (
+	"bufio"
+	"bytes"
+	"encoding/json"
+	"fmt"
+	"io"
+)
+
+const (
+	// MaxLineBytes is the maximum size of a single JSON line accepted by the JSONL protocol.
+	// 1 MiB is enough for fairly large base64 pixel payloads while keeping memory bounded.
+	MaxLineBytes = 1 << 20
+)
+
+// ReadLine reads a single '\n'-terminated line from r with a hard size limit.
+func ReadLine(r *bufio.Reader) ([]byte, error) {
+	var buf bytes.Buffer
+	for {
+		chunk, isPrefix, err := r.ReadLine()
+		if err != nil {
+			if err == io.EOF && buf.Len() > 0 {
+				return buf.Bytes(), nil
+			}
+			return nil, err
+		}
+		buf.Write(chunk)
+		if buf.Len() > MaxLineBytes {
+			return nil, fmt.Errorf("jsonl line too large (> %d bytes)", MaxLineBytes)
+		}
+		if !isPrefix {
+			break
+		}
+	}
+	return buf.Bytes(), nil
+}
+
+func EncodeLine(w io.Writer, v any) error {
+	b, err := json.Marshal(v)
+	if err != nil {
+		return err
+	}
+	b = append(b, '\n')
+	_, err = w.Write(b)
+	return err
+}
+
+func DecodeRequestLine(line []byte) (*Request, error) {
+	var req Request
+	if err := json.Unmarshal(line, &req); err != nil {
+		return nil, err
+	}
+	return &req, nil
+}

internal/ipc/protocol.go

@@ -0,0 +1,22 @@
+package ipc
+
+// JSONL request/response protocol shared by bleh and blehd.
+
+type Request struct {
+	ID     string         `json:"id"`
+	Method string         `json:"method"`
+	Params map[string]any `json:"params,omitempty"`
+}
+
+type Error struct {
+	Code    string `json:"code"`
+	Message string `json:"message"`
+}
+
+type Response struct {
+	ID     string `json:"id,omitempty"`
+	OK     bool   `json:"ok"`
+	Result any    `json:"result,omitempty"`
+	Error  *Error `json:"error,omitempty"`
+	Event  string `json:"event,omitempty"`
+}