More session id work

include/parselink/proto/session_id.h

@@ -27,20 +27,42 @@ namespace parselink {
 namespace proto {
 
 struct session_id {
-    std::array<std::byte, 32> bytes;
+public:
     session_id() noexcept;
 
+    // Not the intended way to build a session id. Ideally, they'll be randomly
+    // generated.
+    explicit constexpr session_id(std::array<std::byte, 32> const& v) noexcept {
+        std::copy(v.begin(), v.end(), bytes_.begin());
+    }
+
     [[nodiscard]] constexpr auto operator<=>(
             session_id const& other) const noexcept {
-        return bytes <=> other.bytes;
+        return bytes_ <=> other.bytes_;
+    }
+
+    [[nodiscard]] constexpr auto operator==(
+            session_id const& other) const noexcept {
+        return bytes_ == other.bytes_;
     }
 
     [[nodiscard]] constexpr auto operator<=>(
             std::span<std::byte const> other) const noexcept {
-        return std::lexicographical_compare_three_way(bytes.begin(),
-                bytes.end(), other.begin(), other.end(),
+        return std::lexicographical_compare_three_way(bytes_.begin(),
+                bytes_.end(), other.begin(), other.end(),
                 std::compare_three_way());
     }
+
+    [[nodiscard]] constexpr auto operator==(
+            std::span<std::byte const> other) const noexcept {
+        return std::equal(bytes_.begin(), bytes_.end(), other.begin(), other.end());
+    }
+
+    constexpr std::span<std::byte const> raw() const noexcept {
+        return bytes_;
+    }
+private:
+    std::array<std::byte, 32> bytes_;
 };
 
 } // namespace proto

source/proto/BUILD

@@ -4,6 +4,7 @@ cc_library(
     name = "proto",
     srcs = [
         "session.cpp",
+        "session_id.cpp",
     ],
     deps = [
         "//include/parselink:proto",

source/proto/session_id.cpp

@@ -0,0 +1,38 @@
+//-----------------------------------------------------------------------------
+//     ___                      __ _       _
+//    / _ \__ _ _ __ ___  ___  / /(_)_ __ | | __
+//   / /_)/ _` | '__/ __|/ _ \/ / | | '_ \| |/ /
+//  / ___/ (_| | |  \__ \  __/ /__| | | | |   <
+//  \/    \__,_|_|  |___/\___\____/_|_| |_|_|\_\ .
+//
+//-----------------------------------------------------------------------------
+// Author: Kurt Sassenrath
+// Module: proto
+//
+// Session ID implementation
+//
+// Copyright (c) 2023 Kurt Sassenrath.
+//
+// License TBD.
+//-----------------------------------------------------------------------------
+#include "parselink/proto/session_id.h"
+
+#include "hydrogen.h"
+
+namespace {
+void ensure_initialized() {
+    static auto init_crng [[maybe_unused]] = [] { return hydro_init(); }();
+}
+
+template <std::size_t N>
+auto get_random_bytes() {
+    ensure_initialized();
+    std::array<std::byte, N> out;
+    hydro_random_buf(out.data(), N);
+    return out;
+}
+
+}
+
+using namespace parselink::proto;
+session_id::session_id() noexcept : bytes_(get_random_bytes<32>()) {}

tests/proto/BUILD

@@ -0,0 +1,22 @@
+
+cc_library(
+    name = "test_deps",
+    srcs = [
+        "test_main.cpp",
+    ],
+    deps = [
+        "//source/proto",
+        "@expected",
+        "@fmt",
+        "@magic_enum",
+        "@ut",
+    ],
+)
+
+cc_test(
+    name = "session_id",
+    srcs = [
+        "test_session_id.cpp",
+    ],
+    deps = ["test_deps"],
+)

tests/proto/test_main.cpp

@@ -0,0 +1,2 @@
+
+int main(int, char**) {}

tests/proto/test_session_id.cpp

@@ -0,0 +1,52 @@
+#include <boost/ut.hpp>
+#include <parselink/proto/session_id.h>
+
+#include <set>
+
+namespace {
+
+using namespace boost::ut;
+using namespace parselink::proto;
+
+template <typename... Bytes>
+constexpr std::array<std::byte, sizeof...(Bytes)> make_bytes(Bytes&&... bytes) {
+    return {std::byte(std::forward<Bytes>(bytes))...};
+}
+
+constexpr std::array<std::byte, 32> null_id_bytes = {};
+
+}
+
+suite session_id_tests = [] {
+    "test explicitly generated session ids"_test = [] {
+        constexpr session_id sid1(null_id_bytes);
+        constexpr session_id sid2(null_id_bytes);
+        expect(sid1 == sid2);
+        expect(sid1 == null_id_bytes);
+        constexpr auto basic_id = make_bytes(
+                0x0, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f,
+                0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17, 0x18, 0x19, 0x1a, 0x1b, 0x1c, 0x1d, 0x1e, 0x1f);
+        constexpr session_id sid3(basic_id);
+        constexpr session_id sid4(basic_id);
+        expect(sid3 == sid4);
+        expect(sid3 == basic_id);
+    };
+
+    "test random generated"_test = [] {
+        session_id sid1;
+        session_id sid2;
+        expect(sid1 != null_id_bytes);
+        expect(sid2 != null_id_bytes);
+        expect(sid1 != sid2);
+    };
+
+    "test random generated entropy"_test = [] {
+        constexpr static std::size_t iter_count = 100000;
+        std::set<session_id> sessions;
+        while (sessions.size() < iter_count) {
+            session_id s;
+            expect(!sessions.contains(s));
+            sessions.insert(std::move(s));
+        }
+    };
+};