update ErrorCode, status, lifecycle

include/lidarlib/error.hpp

@@ -0,0 +1,46 @@
+#pragma once
+
+namespace lidarlib {
+
+// Result of open() and the sticky status behind last_error(). Ok == 0 so
+// `if (err != ErrorCode::Ok)` reads naturally at call sites.
+enum class ErrorCode {
+    Ok = 0,
+
+    // Lifecycle misuse — the call was refused, the instance state is unchanged.
+    AlreadyOpen,          // open() called while already open
+    NotOpen,              // recv_scan()/spin_once() called before open()
+
+    // open() failures
+    SocketError,          // socket() creation failed
+    InvalidAddress,       // ip string is not a valid IPv4 address
+    PortInUse,            // bind: local port already taken (EADDRINUSE/EACCES)
+    BindFailed,           // bind failed for another reason
+    ConnectionRefused,    // TCP connect refused (device up, port closed)
+    ConnectionFailed,     // TCP connect failed (unreachable, no route, ...)
+    HandshakeFailed,      // connected, but the start-stream command failed
+
+    // Runtime failures
+    Timeout,              // no (complete) scan within timeout_ms
+    DeviceDisconnected,   // peer closed the connection / socket recv error
+};
+
+inline const char* to_string(ErrorCode e) {
+    switch (e) {
+        case ErrorCode::Ok:                 return "Ok";
+        case ErrorCode::AlreadyOpen:        return "AlreadyOpen";
+        case ErrorCode::NotOpen:            return "NotOpen";
+        case ErrorCode::SocketError:        return "SocketError";
+        case ErrorCode::InvalidAddress:     return "InvalidAddress";
+        case ErrorCode::PortInUse:          return "PortInUse";
+        case ErrorCode::BindFailed:         return "BindFailed";
+        case ErrorCode::ConnectionRefused:  return "ConnectionRefused";
+        case ErrorCode::ConnectionFailed:   return "ConnectionFailed";
+        case ErrorCode::HandshakeFailed:    return "HandshakeFailed";
+        case ErrorCode::Timeout:            return "Timeout";
+        case ErrorCode::DeviceDisconnected: return "DeviceDisconnected";
+    }
+    return "Unknown";
+}
+
+} // namespace lidarlib