Merge remote-tracking branch 'upstream/3.4' into merge-3.4

modules/core/include/opencv2/core/persistence.hpp

@@ -544,6 +544,11 @@ public:
     */
     CV_WRAP_AS(at) FileNode operator[](int i) const;
 
+    /** @brief Returns keys of a mapping node.
+    @returns Keys of a mapping node.
+     */
+    CV_WRAP std::vector<String> keys() const;
+
     /** @brief Returns type of the node.
     @returns Type of the node. See FileNode::Type
      */

modules/core/src/matrix.cpp

@@ -355,15 +355,16 @@ void Mat::create(int d, const int* _sizes, int _type)
 #endif
         if(!a)
             a = a0;
-        CV_TRY
+        try
         {
             u = a->allocate(dims, size, _type, 0, step.p, ACCESS_RW /* ignored */, USAGE_DEFAULT);
             CV_Assert(u != 0);
         }
-        CV_CATCH_ALL
+        catch (...)
         {
-            if(a != a0)
-                u = a0->allocate(dims, size, _type, 0, step.p, ACCESS_RW /* ignored */, USAGE_DEFAULT);
+            if (a == a0)
+                throw;
+            u = a0->allocate(dims, size, _type, 0, step.p, ACCESS_RW /* ignored */, USAGE_DEFAULT);
             CV_Assert(u != 0);
         }
         CV_Assert( step[dims-1] == (size_t)CV_ELEM_SIZE(flags) );

modules/core/src/persistence_cpp.cpp

@@ -274,6 +274,20 @@ FileNode FileNode::operator[](int i) const
         i == 0 ? *this : FileNode();
 }
 
+std::vector<String> FileNode::keys() const
+{
+    std::vector<String> res;
+    if (isMap())
+    {
+        res.reserve(size());
+        for (FileNodeIterator it = begin(); it != end(); ++it)
+        {
+            res.push_back((*it).name());
+        }
+    }
+    return res;
+}
+
 String FileNode::name() const
 {
     const char* str;