From bd6784b57909a87134c8bb5ddec73b27b8f1260b Mon Sep 17 00:00:00 2001
From: Andrei Golubev <andrei.golubev@qt.io>
Date: Wed, 4 Nov 2020 16:56:53 +0100
Subject: [PATCH] Simplify Q*ArrayOps emplace() signature

Template type never would've worked, really. We relied everywhere
that 'iterator' is comparable to our iterators (in generic version
it should be even the same type - see std::rotate API) and the
iterator type is castable to T* in POD and Movable cases, so
simplify that, no need for extra template boilerplate

Change-Id: I263ae2ba90ca27abceca01fcc21d80a350bbd743
Reviewed-by: Lars Knoll <lars.knoll@qt.io>
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
---
 src/corelib/tools/qarraydataops.h | 37 +++++++++++++++----------------
 1 file changed, 18 insertions(+), 19 deletions(-)

diff --git a/src/corelib/tools/qarraydataops.h b/src/corelib/tools/qarraydataops.h
index 1fd7e99c42..2162512883 100644
--- a/src/corelib/tools/qarraydataops.h
+++ b/src/corelib/tools/qarraydataops.h
@@ -356,7 +356,6 @@ public:
             *where++ = t;
     }
 
-
     template <typename ...Args>
     void emplace(T *where, Args&&... args)
     { emplace(GrowsForwardTag{}, where, std::forward<Args>(args)...); }
@@ -760,13 +759,12 @@ public:
         }
     }
 
-
-    template <typename iterator, typename ...Args>
-    void emplace(iterator where, Args&&... args)
+    template<typename... Args>
+    void emplace(T *where, Args &&... args)
     { emplace(GrowsForwardTag{}, where, std::forward<Args>(args)...); }
 
-    template <typename iterator, typename ...Args>
-    void emplace(GrowsForwardTag, iterator where, Args&&... args)
+    template<typename... Args>
+    void emplace(GrowsForwardTag, T *where, Args &&... args)
     {
         Q_ASSERT(!this->isShared());
         Q_ASSERT(where >= this->begin() && where <= this->end());
@@ -799,8 +797,8 @@ public:
         }
     }
 
-    template <typename iterator, typename ...Args>
-    void emplace(GrowsBackwardsTag, iterator where, Args&&... args)
+    template<typename... Args>
+    void emplace(GrowsBackwardsTag, T *where, Args &&... args)
     {
         Q_ASSERT(!this->isShared());
         Q_ASSERT(where >= this->begin() && where <= this->end());
@@ -1043,14 +1041,14 @@ public:
     // use moving insert
     using QGenericArrayOps<T>::insert;
 
-    template<typename iterator, typename... Args>
-    void emplace(iterator where, Args &&... args)
+    template<typename... Args>
+    void emplace(T *where, Args &&... args)
     {
         emplace(GrowsForwardTag {}, where, std::forward<Args>(args)...);
     }
 
-    template<typename iterator, typename... Args>
-    void emplace(GrowsForwardTag, iterator where, Args &&... args)
+    template<typename... Args>
+    void emplace(GrowsForwardTag, T *where, Args &&... args)
     {
         Q_ASSERT(!this->isShared());
         Q_ASSERT(where >= this->begin() && where <= this->end());
@@ -1068,8 +1066,8 @@ public:
         ++this->size;
     }
 
-    template<typename iterator, typename... Args>
-    void emplace(GrowsBackwardsTag, iterator where, Args &&... args)
+    template<typename... Args>
+    void emplace(GrowsBackwardsTag, T *where, Args &&... args)
     {
         Q_ASSERT(!this->isShared());
         Q_ASSERT(where >= this->begin() && where <= this->end());
@@ -1367,18 +1365,19 @@ public:
 
     }
 
-
-    template <typename iterator, typename ...Args>
-    void emplace(iterator where, Args&&... args)
+    template<typename... Args>
+    void emplace(T *where, Args &&... args)
     {
         Q_ASSERT(!this->isShared());
         Q_ASSERT(where >= this->begin() && where <= this->end());
         Q_ASSERT(this->allocatedCapacity() - this->size >= 1);
 
+        const T *begin = this->begin();
+        const T *end = this->end();
         // Qt5 QList in insert(1): try to move less data around
         // Now:
-        const bool shouldInsertAtBegin = (where - this->begin()) < (this->end() - where)
-                                         || this->freeSpaceAtEnd() <= 0;
+        const bool shouldInsertAtBegin =
+                (where - begin) < (end - where) || this->freeSpaceAtEnd() <= 0;
         if (this->freeSpaceAtBegin() > 0 && shouldInsertAtBegin) {
             Base::emplace(GrowsBackwardsTag{}, where, std::forward<Args>(args)...);
         } else {