From 0b5108a8a0d9b7a4a63bd6aae0271b71a887beea Mon Sep 17 00:00:00 2001
From: Benoit Germain <benoit.germain@ubisoft.com>
Date: Thu, 25 Apr 2024 13:36:47 +0200
Subject: C++ integration: cleanup in Linda/Keeper interaction

---
 src/linda.h | 70 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 70 insertions(+)
 create mode 100644 src/linda.h

(limited to 'src/linda.h')

diff --git a/src/linda.h b/src/linda.h
new file mode 100644
index 0000000..559ef24
--- /dev/null
+++ b/src/linda.h
@@ -0,0 +1,70 @@
+#pragma once
+
+#include "cancel.h"
+#include "deep.h"
+#include "keeper.h"
+#include "universe.h"
+
+#include <array>
+#include <condition_variable>
+#include <variant>
+
+struct Keeper;
+
+// #################################################################################################
+
+using LindaGroup = Unique<int>;
+
+class Linda : public DeepPrelude // Deep userdata MUST start with this header
+{
+    private:
+
+    static constexpr size_t kEmbeddedNameLength = 24;
+    using EmbeddedName = std::array<char, kEmbeddedNameLength>;
+    struct AllocatedName
+    {
+        size_t len{ 0 };
+        char* name{ nullptr };
+    };
+    // depending on the name length, it is either embedded inside the Linda, or allocated separately
+    std::variant<AllocatedName, EmbeddedName> m_name;
+
+    public:
+
+    std::condition_variable m_read_happened;
+    std::condition_variable m_write_happened;
+    Universe* const U{ nullptr }; // the universe this linda belongs to
+    int const m_keeper_index{ -1 }; // the keeper associated to this linda
+    CancelRequest simulate_cancel{ CancelRequest::None };
+
+    public:
+
+    // a fifo full userdata has one uservalue, the table that holds the actual fifo contents
+    [[nodiscard]] static void* operator new(size_t size_, Universe* U_) noexcept { return U_->internal_allocator.alloc(size_); }
+    // always embedded somewhere else or "in-place constructed" as a full userdata
+    // can't actually delete the operator because the compiler generates stack unwinding code that could call it in case of exception
+    static void operator delete(void* p_, Universe* U_) { U_->internal_allocator.free(p_, sizeof(Linda)); }
+    // this one is for us, to make sure memory is freed by the correct allocator
+    static void operator delete(void* p_) { static_cast<Linda*>(p_)->U->internal_allocator.free(p_, sizeof(Linda)); }
+
+    ~Linda();
+    Linda(Universe* U_, LindaGroup group_, char const* name_, size_t len_);
+    Linda() = delete;
+    Linda(Linda const&) = delete;
+    Linda(Linda const&&) = delete;
+    Linda& operator=(Linda const&) = delete;
+    Linda& operator=(Linda const&&) = delete;
+
+    static int ProtectedCall(lua_State* L, lua_CFunction f_);
+
+    private :
+
+    void setName(char const* name_, size_t len_);
+
+    public:
+
+    [[nodiscard]] char const* getName() const;
+    [[nodiscard]] Keeper* whichKeeper() const { return U->keepers->nb_keepers ? &U->keepers->keeper_array[m_keeper_index] : nullptr; }
+    [[nodiscard]] Keeper* acquireKeeper() const;
+    void releaseKeeper(Keeper* keeper_) const;
+};
-- 
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