initial import from picomap firmware

include/dispatch.h

@@ -0,0 +1,60 @@
+#pragma once
+#include <cstdint>
+#include <cstdio>
+#include <optional>
+#include <span>
+#include "wire.h"
+#include "timer_queue.h"
+#include "net.h"
+#include "prepend_buffer.h"
+#include "udp.h"
+
+uint16_t dispatch_listen_port_be();
+
+struct responder {
+    uint32_t message_id;
+    udp::address reply_to;
+
+    template <typename T>
+    void respond(const T& msg) const {
+        const auto& ns = net_get_state();
+        prepend_buffer<4096> buf;
+        span_writer out(buf.payload_ptr(), 2048);
+        auto r = encode_response_into(out, message_id, msg);
+        if (!r) return;
+        buf.append(*r);
+        udp::prepend(buf, reply_to.mac, ns.mac, ns.ip, reply_to.ip,
+                     dispatch_listen_port_be(), reply_to.port, *r);
+        net_send_raw(buf.span());
+    }
+};
+
+using handler_fn = void (*)(const responder& resp, std::span<const uint8_t> payload);
+
+struct handler_entry {
+    int8_t type_id;
+    handler_fn handle;
+};
+
+template <typename Req, auto Fn>
+void typed_handler(const responder& resp, std::span<const uint8_t> payload) {
+    msgpack::parser p(payload.data(), static_cast<int>(payload.size()));
+    Req req;
+    auto tup = req.as_tuple();
+    auto r = msgpack::unpack(p, tup);
+    if (!r) {
+        char err[64];
+        snprintf(err, sizeof(err), "decode request ext_id=%d: msgpack error %d",
+                 Req::ext_id, static_cast<int>(r.error()));
+        resp.respond(DeviceError{1, err});
+        return;
+    }
+    auto result = Fn(resp, req);
+    if (result)
+        resp.respond(*result);
+}
+
+void dispatch_init(uint16_t listen_port_be);
+timer_handle dispatch_schedule_ms(uint32_t ms, void (*fn)());
+bool dispatch_cancel_timer(timer_handle h);
+[[noreturn]] void dispatch_run(std::span<const handler_entry> handlers);