From 75986911f88b78b54811db6a19f8009c6f9c41a3 Mon Sep 17 00:00:00 2001
From: Maxime Coste <mawww@kakoune.org>
Date: Sat, 3 Dec 2016 12:32:16 +0000
Subject: [PATCH] Refactor RefPtr handling to use a policy class

THe previous overload based system was pretty complex for no good
reason.
---
 src/ref_ptr.hh       | 41 +++++++++--------------
 src/safe_ptr.hh      | 79 ++++++++++++++++++++++----------------------
 src/shared_string.hh | 13 ++++++--
 3 files changed, 66 insertions(+), 67 deletions(-)

diff --git a/src/ref_ptr.hh b/src/ref_ptr.hh
index a061cff9..279686b3 100644
--- a/src/ref_ptr.hh
+++ b/src/ref_ptr.hh
@@ -6,12 +6,20 @@
 namespace Kakoune
 {
 
-struct WorstMatch { [[gnu::always_inline]] WorstMatch(...) {} };
+struct RefCountable
+{
+    int refcount = 0;
+    virtual ~RefCountable() = default;
+};
 
-[[gnu::always_inline]]
-inline void ref_ptr_moved(WorstMatch, void*, void*) noexcept {}
+struct RefCountablePolicy
+{
+    static void inc_ref(RefCountable* r, void*) { ++r->refcount; }
+    static void dec_ref(RefCountable* r, void*) { if (--r->refcount == 0) delete r; }
+    static void ptr_moved(RefCountable*, void*, void*) noexcept {}
+};
 
-template<typename T, typename TForOverload = T>
+template<typename T, typename Policy = RefCountablePolicy>
 struct RefPtr
 {
     RefPtr() = default;
@@ -83,40 +91,23 @@ private:
     void acquire()
     {
         if (m_ptr)
-            inc_ref_count(static_cast<TForOverload*>(m_ptr), this);
+            Policy::inc_ref(m_ptr, this);
     }
 
     [[gnu::always_inline]]
     void release()
     {
         if (m_ptr)
-            dec_ref_count(static_cast<TForOverload*>(m_ptr), this);
+            Policy::dec_ref(m_ptr, this);
         m_ptr = nullptr;
     }
 
     [[gnu::always_inline]]
     void moved(void* from)
-        noexcept(noexcept(ref_ptr_moved(static_cast<TForOverload*>(nullptr), nullptr, nullptr)))
+        noexcept(noexcept(Policy::ptr_moved(nullptr, nullptr, nullptr)))
     {
         if (m_ptr)
-            ref_ptr_moved(static_cast<TForOverload*>(m_ptr), from, this);
-    }
-};
-
-struct RefCountable
-{
-    int refcount = 0;
-    virtual ~RefCountable() = default;
-
-    friend void inc_ref_count(RefCountable* r, void*)
-    {
-        ++r->refcount;
-    }
-
-    friend void dec_ref_count(RefCountable* r, void*)
-    {
-        if (--r->refcount == 0)
-            delete r;
+            Policy::ptr_moved(m_ptr, from, this);
     }
 };
 
diff --git a/src/safe_ptr.hh b/src/safe_ptr.hh
index 12a9b4a3..b9f53709 100644
--- a/src/safe_ptr.hh
+++ b/src/safe_ptr.hh
@@ -33,37 +33,8 @@ public:
         #endif
     }
 
-    friend void inc_ref_count(const SafeCountable* sc, void* ptr)
-    {
-        ++sc->m_count;
-        #ifdef SAFE_PTR_TRACK_CALLSTACKS
-        sc->m_callstacks.emplace_back(ptr);
-        #endif
-    }
-
-    friend void dec_ref_count(const SafeCountable* sc, void* ptr)
-    {
-        --sc->m_count;
-        kak_assert(sc->m_count >= 0);
-        #ifdef SAFE_PTR_TRACK_CALLSTACKS
-        auto it = std::find_if(sc->m_callstacks.begin(), sc->m_callstacks.end(),
-                               [=](const Callstack& cs) { return cs.ptr == ptr; });
-        kak_assert(it != sc->m_callstacks.end());
-        sc->m_callstacks.erase(it);
-        #endif
-    }
-
-    friend void ref_ptr_moved(const SafeCountable* sc, void* from, void* to)
-    {
-        #ifdef SAFE_PTR_TRACK_CALLSTACKS
-        auto it = std::find_if(sc->m_callstacks.begin(), sc->m_callstacks.end(),
-                               [=](const Callstack& cs) { return cs.ptr == from; });
-        kak_assert(it != sc->m_callstacks.end());
-        it->ptr = to;
-        #endif
-    }
-
 private:
+    friend struct SafeCountablePolicy;
     #ifdef SAFE_PTR_TRACK_CALLSTACKS
     struct Callstack
     {
@@ -75,20 +46,50 @@ private:
     mutable Vector<Callstack> m_callstacks;
     #endif
     mutable int m_count;
-#else
-    [[gnu::always_inline]]
-    friend void inc_ref_count(const SafeCountable* sc, void* ptr) {}
-
-    [[gnu::always_inline]]
-    friend void dec_ref_count(const SafeCountable* sc, void* ptr) {}
 #endif
 };
 
-template<typename T, typename U>
-using PropagateConst = typename std::conditional<std::is_const<T>::value, const U, U>::type;
+struct SafeCountablePolicy
+{
+#ifdef KAK_DEBUG
+    static void inc_ref(const SafeCountable* sc, void* ptr)
+    {
+        ++sc->m_count;
+        #ifdef SAFE_PTR_TRACK_CALLSTACKS
+        sc->m_callstacks.emplace_back(ptr);
+        #endif
+    }
+
+    static void dec_ref(const SafeCountable* sc, void* ptr)
+    {
+        --sc->m_count;
+        kak_assert(sc->m_count >= 0);
+        #ifdef SAFE_PTR_TRACK_CALLSTACKS
+        auto it = std::find_if(sc->m_callstacks.begin(), sc->m_callstacks.end(),
+                               [=](const Callstack& cs) { return cs.ptr == ptr; });
+        kak_assert(it != sc->m_callstacks.end());
+        sc->m_callstacks.erase(it);
+        #endif
+    }
+
+    static void ptr_moved(const SafeCountable* sc, void* from, void* to)
+    {
+        #ifdef SAFE_PTR_TRACK_CALLSTACKS
+        auto it = std::find_if(sc->m_callstacks.begin(), sc->m_callstacks.end(),
+                               [=](const Callstack& cs) { return cs.ptr == from; });
+        kak_assert(it != sc->m_callstacks.end());
+        it->ptr = to;
+        #endif
+    }
+#else
+    static void inc_ref(const SafeCountable*, void* ptr) {}
+    static void dec_ref(const SafeCountable*, void* ptr) {}
+    static void ptr_moved(const SafeCountable*, void*, void*) {}
+#endif
+};
 
 template<typename T>
-using SafePtr = RefPtr<T, PropagateConst<T, SafeCountable>>;
+using SafePtr = RefPtr<T, SafeCountablePolicy>;
 
 }
 
diff --git a/src/shared_string.hh b/src/shared_string.hh
index 112b67f2..49bbdb4c 100644
--- a/src/shared_string.hh
+++ b/src/shared_string.hh
@@ -24,7 +24,14 @@ struct StringData : UseMemoryDomain<MemoryDomain::SharedString>
     [[gnu::always_inline]]
     StringView strview() const { return {data(), length}; }
 
-    static RefPtr<StringData> create(StringView str, char back = 0)
+    struct PtrPolicy
+    {
+        static void inc_ref(StringData* r, void*) { ++r->refcount; }
+        static void dec_ref(StringData* r, void*) { if (--r->refcount == 0) delete r; }
+        static void ptr_moved(StringData*, void*, void*) noexcept {}
+    };
+
+    static RefPtr<StringData, PtrPolicy> create(StringView str, char back = 0)
     {
         const int len = (int)str.length() + (back != 0 ? 1 : 0);
         void* ptr = StringData::operator new(sizeof(StringData) + len + 1);
@@ -34,7 +41,7 @@ struct StringData : UseMemoryDomain<MemoryDomain::SharedString>
             res->data()[len-1] = back;
         res->data()[len] = 0;
         res->hash = hash_data(res->data(), res->length);
-        return RefPtr<StringData>(res);
+        return RefPtr<StringData, PtrPolicy>{res};
     }
 
     static void destroy(StringData* s)
@@ -54,7 +61,7 @@ struct StringData : UseMemoryDomain<MemoryDomain::SharedString>
     }
 };
 
-using StringDataPtr = RefPtr<StringData>;
+using StringDataPtr = RefPtr<StringData, StringData::PtrPolicy>;
 
 class StringRegistry : public Singleton<StringRegistry>
 {