mana::Arena: fixes and segment limit and tests

src/CMakeLists.txt

@@ -1,4 +1,4 @@
-set(MVLC_NNG_MNODE_WARN_FLAGS -Wall -Wextra -Wpedantic)
+set(MVLC_NNG_MNODE_WARN_FLAGS -Wall -Wextra -Wpedantic -Werror=return-type)
 
 add_library(mesytec-mnode mnode_nng.cc mnode_nng_async.cc mnode_nng_proto.cc)
 target_include_directories(mesytec-mnode
@@ -13,7 +13,7 @@ add_subdirectory(tools)
 if (MNODE_BUILD_TESTS)
     function (add_mnode_gtest name)
         add_executable(test_${name} ${name}.test.cc)
-        target_link_libraries(test_${name} PRIVATE mesytec-mnode GTest::gtest_main)
+        target_link_libraries(test_${name} PRIVATE mesytec-mnode GTest::gtest_main spdlog)
         add_test(NAME name COMMAND $<TARGET_FILE:test_${name}>)
     endfunction()
 

src/internal/mana_arena.h

@@ -14,6 +14,7 @@ class Arena
   public:
     static constexpr size_t initial_segment_size = 1u << 20;
     static constexpr size_t default_pad = 8;
+    static constexpr size_t default_max_segments = 1;
 
     Arena() = default;
     ~Arena() = default;
@@ -32,19 +33,27 @@ class Arena
 
         if (!segment_ || segment_->free() < required)
         {
-            // could waste complete segments if required > default size of 1u << 20 but that's fine
-            // for now
-            segment_ =
-                &segments_.emplace_back(Arena::Segment(std::max(required, initial_segment_size)));
+            if (segment_count() < max_segments())
+            {
+                // could waste complete segments if required > default size of 1u << 20 but that's
+                // fine for now
+                segment_ = &segments_.emplace_back(
+                    Arena::Segment(std::max(required, initial_segment_size)));
+            }
+            else
+            {
+                throw std::bad_alloc();
+            }
         }
 
         assert(segment_ && segment_->free() >= required);
 
-        std::memset(segment_->cur(), 0, required);
+        auto result = segment_->cur();
+        std::memset(result, 0, required);
         segment_->used += required;
         ++allocations_;
         pad_waste_ += pad_waste;
-        return segment_->cur();
+        return result;
     }
 
     template <typename T> T *push_t(size_t count = 1)
@@ -53,11 +62,11 @@ class Arena
         return reinterpret_cast<T *>(push_size(sizeof(T) * count));
     }
 
-    const char *push_cstr(const std::string &str)
+    char *push_cstr(const std::string &str)
     {
         auto mem = push_size(str.size() + 1);
         std::memcpy(mem, str.c_str(), str.size());
-        return reinterpret_cast<const char *>(mem);
+        return reinterpret_cast<char *>(mem);
     }
 
     void reset()
@@ -69,6 +78,7 @@ class Arena
         pad_waste_ = 0;
     }
 
+    size_t max_segments() const { return max_segments_; }
     size_t allocations() const { return allocations_; }
     size_t pad_waste() const { return pad_waste_; }
     size_t segment_count() const { return segments_.size(); }
@@ -83,9 +93,13 @@ class Arena
     {
         auto accu = [](size_t sum, const Segment &seg) { return sum + seg.used; };
         return std::accumulate(std::begin(segments_), std::end(segments_), static_cast<size_t>(0u),
-                               accu) - pad_waste_;
+                               accu) -
+               pad_waste_;
     }
 
+    const u8 *cur_begin() const { return segment_ ? segment_->data.data() : nullptr; }
+    const u8 *cur_end() const { return segment_ ? segment_->cur() : nullptr; }
+
   private:
     Arena(const Arena &) = delete;
     Arena &operator=(const Arena &) = delete;
@@ -105,6 +119,7 @@ class Arena
         void reset() { used = 0; }
     };
 
+    size_t max_segments_ = default_max_segments;
     std::list<Segment> segments_;
     Segment *segment_ = nullptr;
     size_t allocations_ = 0;

src/mana.test.cc

@@ -1,10 +1,13 @@
 #include <gtest/gtest.h>
 #include <mesytec-mnode/mnode_cpp_types.h>
 #include "internal/mana_arena.h"
+#include <spdlog/spdlog.h>
+#include "tools/mana_replay_api.h"
+#include "tools/mana_lib.hpp"
 
 using namespace mesytec::mnode;
 
-TEST(mnode_mana, Arena)
+TEST(mnode_mana_arena, push_reset_push)
 {
     mana::Arena arena;
 
@@ -33,4 +36,76 @@ TEST(mnode_mana, Arena)
     ASSERT_GE(arena.segment_count(), 1);
     ASSERT_GE(arena.capacity(), 10 * (mana::Arena::default_pad + 2));
     ASSERT_EQ(arena.used(), 0);
+
+    for (size_t i = 0; i < 10; ++i)
+    {
+        auto mem = arena.push_size(mana::Arena::default_pad + 2);
+        ASSERT_NE(mem, nullptr);
+    }
+
+    ASSERT_EQ(arena.allocations(), 10);
+    ASSERT_GE(arena.pad_waste(), 0);
+    ASSERT_GE(arena.segment_count(), 1);
+    ASSERT_GE(arena.capacity(), 10 * (mana::Arena::default_pad + 2));
+    ASSERT_EQ(arena.used(), 10 * (mana::Arena::default_pad + 2));
+}
+
+TEST(mnode_mana_offset_ptr, basic)
+{
+    using namespace mana;
+
+    struct OffsetPtrTest
+    {
+        u32 a;
+        mana_offset_ptr_t ptr0; // &a
+        mana_offset_ptr_t ptr1; // &b
+        u32 b;
+    };
+
+    mana::Arena arena;
+
+    auto t = arena.push_t<OffsetPtrTest>();
+    t->a = 42;
+    t->b = 43;
+
+    set(t->ptr0, &t->a);
+    set(t->ptr1, &t->b);
+
+    ASSERT_EQ(get<u32>(t->ptr0), &t->a);
+    ASSERT_EQ(get<u32>(t->ptr1), &t->b);
+    ASSERT_EQ(get<double>(t->ptr0), nullptr);
+    ASSERT_EQ(get<double>(t->ptr1), nullptr);
+}
+
+TEST(mnode_mana_offset_ptr, strings)
+{
+    using namespace mana;
+
+    struct OffsetPtrTest
+    {
+        mana_offset_ptr_t ptr0;
+        mana_offset_ptr_t ptr1;
+    };
+
+    mana::Arena arena;
+
+    auto t = arena.push_t<OffsetPtrTest>();
+
+    auto s0 = arena.push_cstr("hello");
+    auto s1 = arena.push_cstr("world");
+
+    spdlog::info("&t->ptr0={}, &t->ptr1={}", fmt::ptr(&t->ptr0), fmt::ptr(&t->ptr1));
+    spdlog::info("s0={} @ {}, s1={} @ {}", s0, fmt::ptr(s0), s1, fmt::ptr(s1));
+
+    set(t->ptr0, s0);
+    set(t->ptr1, s1);
+
+    ASSERT_EQ(get<char>(t->ptr0), std::string("hello"));
+    ASSERT_EQ(get<char>(t->ptr1), std::string("world"));
+    ASSERT_EQ(get<double>(t->ptr0), nullptr);
+    ASSERT_EQ(get<double>(t->ptr1), nullptr);
+
+    set(t->ptr0, nullptr);
+    ASSERT_EQ(get<char>(t->ptr0), nullptr);
+    ASSERT_EQ(get<char>(t->ptr1), std::string("world"));
 }