Fix inserting an element of wxArrayString itself back into it.

Do the insertion/addition before deallocating the old memory to allow things
like array.Add(array[0]) to work correctly.

Closes #2290.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@76909 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/arrstr.h

@@ -364,7 +364,10 @@ protected:
   CompareFunction m_compareFunction;    // set only from wxSortedArrayString
 
 private:
-  void Grow(size_t nIncrement = 0);     // makes array bigger if needed
+  // Allocate the new buffer big enough to hold m_nCount + nIncrement items and
+  // return the pointer to the old buffer, which must be deleted by the caller
+  // (if the old buffer is big enough, just return NULL).
+  wxString *Grow(size_t nIncrement);
 
   size_t  m_nSize,    // current size of the array
           m_nCount;   // current number of elements

src/common/arrstr.cpp

@@ -20,6 +20,7 @@
 #endif
 
 #include "wx/arrstr.h"
+#include "wx/scopedarray.h"
 
 #include "wx/beforestd.h"
 #include <algorithm>
@@ -107,10 +108,14 @@ void wxArrayString::Copy(const wxArrayString& src)
 }
 
 // grow the array
-void wxArrayString::Grow(size_t nIncrement)
+wxString *wxArrayString::Grow(size_t nIncrement)
 {
-  // only do it if no more place
-  if ( (m_nSize - m_nCount) < nIncrement ) {
+    if ( (m_nSize - m_nCount) >= nIncrement )
+    {
+        // We already have enough space.
+        return NULL;
+    }
+
     // if ARRAY_DEFAULT_INITIAL_SIZE were set to 0, the initially empty would
     // be never resized!
     #if ARRAY_DEFAULT_INITIAL_SIZE == 0
@@ -123,6 +128,9 @@ void wxArrayString::Grow(size_t nIncrement)
       if (m_nSize < nIncrement)
           m_nSize = nIncrement;
       m_pItems = new wxString[m_nSize];
+
+      // Nothing to free, we hadn't had any memory before.
+      return NULL;
     }
     else {
       // otherwise when it's called for the first time, nIncrement would be 0
@@ -141,12 +149,12 @@ void wxArrayString::Grow(size_t nIncrement)
       for ( size_t j = 0; j < m_nCount; j++ )
           pNew[j] = m_pItems[j];
 
-      // delete old memory (but do not release the strings!)
-      delete [] m_pItems;
+      wxString* const pItemsOld = m_pItems;
 
       m_pItems = pNew;
+
+      return pItemsOld;
     }
-  }
 }
 
 // deletes all the strings from the list
@@ -289,7 +297,10 @@ size_t wxArrayString::Add(const wxString& str, size_t nInsert)
     return (size_t)lo;
   }
   else {
-    Grow(nInsert);
+    // Now that we must postpone freeing the old memory until we don't need it
+    // any more, i.e. don't reference "str" which could be a reference to one
+    // of our own strings.
+    wxScopedArray<wxString> oldStrings(Grow(nInsert));
 
     for (size_t i = 0; i < nInsert; i++)
     {
@@ -309,7 +320,7 @@ void wxArrayString::Insert(const wxString& str, size_t nIndex, size_t nInsert)
   wxCHECK_RET( m_nCount <= m_nCount + nInsert,
                wxT("array size overflow in wxArrayString::Insert") );
 
-  Grow(nInsert);
+  wxScopedArray<wxString> oldStrings(Grow(nInsert));
 
   for (int j = m_nCount - nIndex - 1; j >= 0; j--)
       m_pItems[nIndex + nInsert + j] = m_pItems[nIndex + j];
@@ -328,7 +339,7 @@ wxArrayString::insert(iterator it, const_iterator first, const_iterator last)
     const int idx = it - begin();
 
     // grow it once
-    Grow(last - first);
+    wxScopedArray<wxString> oldStrings(Grow(last - first));
 
     // reset "it" since it can change inside Grow()
     it = begin() + idx;

tests/arrays/arrays.cpp

@@ -346,6 +346,10 @@ void ArraysTestCase::wxStringArrayTest()
     a5.resize(3);
     CPPUNIT_ASSERT_EQUAL( 3, a5.size() );
     CPPUNIT_ASSERT_EQUAL( "Foo", a5[2] );
+
+    wxArrayString a6;
+    a6.Add("Foo");
+    a6.Insert(a6[0], 1, 100);
 }
 
 void ArraysTestCase::SortedArray()