From 4af6ba40c29af98f4ecb01d9d2654c02043c3e44 Mon Sep 17 00:00:00 2001
From: Marc Mutz <marc.mutz@qt.io>
Date: Tue, 30 Nov 2021 16:35:06 +0100
Subject: [PATCH] QVLA: separate control from inline storage [6/N]:
 emplace_back()
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Move emplace_back() down from QVarLengthArray to QVLABase.

Task-number: QTBUG-84785
Change-Id: I29020737007f245c3b52fd7960369262510c0d52
Reviewed-by: Mårten Nordheim <marten.nordheim@qt.io>
---
 src/corelib/tools/qvarlengtharray.h | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/src/corelib/tools/qvarlengtharray.h b/src/corelib/tools/qvarlengtharray.h
index 4c8fbc3e0e..d8eab35a56 100644
--- a/src/corelib/tools/qvarlengtharray.h
+++ b/src/corelib/tools/qvarlengtharray.h
@@ -194,6 +194,16 @@ public:
     iterator erase(const_iterator pos) { return erase(pos, pos + 1); }
 
 protected:
+    template <typename...Args>
+    reference emplace_back_impl(qsizetype prealloc, void *array, Args&&...args)
+    {
+        if (size() == capacity()) // ie. size() != 0
+            reallocate_impl(prealloc, array, size(), size() << 1);
+        reference r = *new (end()) T(std::forward<Args>(args)...);
+        ++s;
+        return r;
+    }
+
     template <typename S>
     bool equal(const QVLABase<S> &other) const
     {
@@ -514,7 +524,8 @@ public:
     template <typename...Args>
     iterator emplace(const_iterator pos, Args &&...args);
     template <typename...Args>
-    T &emplace_back(Args &&...args) { return *emplace(cend(), std::forward<Args>(args)...); }
+    T &emplace_back(Args &&...args)
+    { return Base::emplace_back_impl(Prealloc, this->array, std::forward<Args>(args)...); }
 
 
 #ifdef Q_QDOC