Limit for the number of FObject child objects

ChangeLog

@@ -1,5 +1,8 @@
 2020-09-26  Markus Gans  <guru.mail@muenster.de>
 	* FData improvements
+	* The number of FObject children can now be limited with 
+	  setMaxChildren()
+	* FApplication can now have no more than one child widget
 
 2020-09-25  Markus Gans  <guru.mail@muenster.de>
 	* std::clog now streams everything to the FLogger object

src/fapplication.cpp

@@ -388,6 +388,9 @@ void FApplication::processExternalUserEvent()
 //----------------------------------------------------------------------
 void FApplication::init()
 {
+  // FApplication cannot have a second child widget
+  setMaxChildren(1);
+
   // Initialize the last event time
   time_last_event.tv_sec = 0;
   time_last_event.tv_usec = 0;

src/fobject.cpp

@@ -48,7 +48,6 @@ FObject::FObject (FObject* parent)
   if ( parent )                // add object to parent
   {
     parent->addChild(this);
-    has_parent = true;
   }
   else
   {
@@ -107,7 +106,7 @@ FObject* FObject::getChild (int index) const
   if ( ! hasChildren() )
     return nullptr;
 
-  if ( index <= 0 || index > numOfChildren() )
+  if ( index <= 0 || index > int(numOfChildren()) )
     return nullptr;
 
   auto iter = begin();
@@ -148,6 +147,9 @@ void FObject::addChild (FObject* obj)
   if ( ! obj )
     return;
 
+  if ( max_children != UNLIMITED && max_children <= numOfChildren() )
+    throw std::length_error ("max. child objects reached");
+
   if ( obj->parent_obj )
     obj->parent_obj->delChild(obj);
 

src/ftermlinux.cpp

@@ -698,7 +698,7 @@ int FTermLinux::setScreenFont ( const uChar fontdata[], uInt count
     }
 
     for (std::size_t i{0}; i < count; i++)
-      std::memcpy ( const_cast<uChar*>(font.data + bytes_per_line * 32 * i)
+      std::memcpy ( font.data + bytes_per_line * 32 * i
                   , &fontdata[i * font.height]
                   , font.height);
   }

src/include/final/fobject.h

@@ -78,6 +78,9 @@ class FObject
     typedef FObjectList::iterator       iterator;
     typedef FObjectList::const_iterator const_iterator;
 
+    // Constants
+    static constexpr std::size_t UNLIMITED = static_cast<std::size_t>(-1);
+
     // Constructor
     explicit FObject (FObject* = nullptr);
 
@@ -96,12 +99,16 @@ class FObject
     FObject*              getChild (int) const;
     FObjectList&          getChildren();
     const FObjectList&    getChildren() const;
-    int                   numOfChildren() const;
+    std::size_t           getMaxChildren() const;
+    std::size_t           numOfChildren() const;
     iterator              begin();
     iterator              end();
     const_iterator        begin() const;
     const_iterator        end() const;
 
+    // Mutator
+    void                  setMaxChildren (std::size_t);
+
     // Inquiries
     bool                  hasParent() const;
     bool                  hasChildren() const;
@@ -160,6 +167,7 @@ class FObject
     // Data members
     FObject*              parent_obj{nullptr};
     FObjectList           children_list{};  // no children yet
+    std::size_t           max_children{UNLIMITED};
     bool                  has_parent{false};
     bool                  widget_object{false};
     static bool           timer_modify_lock;
@@ -184,8 +192,12 @@ inline const FObject::FObjectList& FObject::getChildren() const
 { return children_list; }
 
 //----------------------------------------------------------------------
-inline int FObject::numOfChildren() const
+inline std::size_t FObject::getMaxChildren() const
-{ return int(children_list.size()); }
+{ return max_children; }
+
+//----------------------------------------------------------------------
+inline std::size_t FObject::numOfChildren() const
+{ return children_list.size(); }
 
 //----------------------------------------------------------------------
 inline FObject::iterator FObject::begin()
@@ -203,6 +215,10 @@ inline FObject::const_iterator FObject::begin() const
 inline FObject::const_iterator FObject::end() const
 { return children_list.end(); }
 
+//----------------------------------------------------------------------
+inline void FObject::setMaxChildren (std::size_t max)
+{ max_children = max; }
+
 //----------------------------------------------------------------------
 inline bool FObject::hasParent() const
 { return has_parent; }

test/fobject-test.cpp

@@ -376,38 +376,57 @@ void FObjectTest::addTest()
 {
   // obj -> child
 
-  auto obj =  new finalcut::FObject();
+  auto obj1 =  new finalcut::FObject();
   auto child = new finalcut::FObject();
 
-  CPPUNIT_ASSERT ( ! obj->hasChildren() );
+  CPPUNIT_ASSERT ( ! obj1->hasChildren() );
-  CPPUNIT_ASSERT ( obj->numOfChildren() == 0 );
+  CPPUNIT_ASSERT ( obj1->numOfChildren() == 0 );
-  CPPUNIT_ASSERT ( ! obj->isChild(child) );
+  CPPUNIT_ASSERT ( ! obj1->isChild(child) );
 
   CPPUNIT_ASSERT ( ! child->hasParent() );
-  CPPUNIT_ASSERT ( child->getParent() != obj );
+  CPPUNIT_ASSERT ( child->getParent() != obj1 );
 
-  obj->addChild(child);
+  obj1->addChild(child);
-  CPPUNIT_ASSERT ( obj->hasChildren() );
+  CPPUNIT_ASSERT ( obj1->hasChildren() );
-  CPPUNIT_ASSERT ( obj->numOfChildren() == 1 );
+  CPPUNIT_ASSERT ( obj1->numOfChildren() == 1 );
-  CPPUNIT_ASSERT ( obj->isChild(child) );
+  CPPUNIT_ASSERT ( obj1->isChild(child) );
 
   CPPUNIT_ASSERT ( child->hasParent() );
-  CPPUNIT_ASSERT ( child->getParent() == obj );
+  CPPUNIT_ASSERT ( child->getParent() == obj1 );
 
   // Switch of the parent by a second addChild
   auto obj2 = new finalcut::FObject();
   obj2->addChild(child);
   CPPUNIT_ASSERT ( child->hasParent() );
-  CPPUNIT_ASSERT ( ! obj->hasChildren() );
+  CPPUNIT_ASSERT ( ! obj1->hasChildren() );
-  CPPUNIT_ASSERT ( obj->numOfChildren() == 0 );
+  CPPUNIT_ASSERT ( obj1->numOfChildren() == 0 );
-  CPPUNIT_ASSERT ( ! obj->isChild(child) );
+  CPPUNIT_ASSERT ( ! obj1->isChild(child) );
-  CPPUNIT_ASSERT ( child->getParent() != obj );
+  CPPUNIT_ASSERT ( child->getParent() != obj1 );
   CPPUNIT_ASSERT ( obj2->hasChildren() );
   CPPUNIT_ASSERT ( obj2->numOfChildren() == 1 );
   CPPUNIT_ASSERT ( obj2->isChild(child) );
   CPPUNIT_ASSERT ( child->getParent() == obj2 );
 
-  delete obj;  // also deletes the child object
+  // Are the maximum number of child objects reached?
+  CPPUNIT_ASSERT ( obj2->getMaxChildren() == finalcut::FObject::UNLIMITED );
+  obj2->setMaxChildren(1);
+  CPPUNIT_ASSERT ( obj2->hasChildren() );
+  CPPUNIT_ASSERT ( obj2->getMaxChildren() == 1 );
+  CPPUNIT_ASSERT ( obj2->numOfChildren() == 1 );
+  auto child2 = new finalcut::FObject();
+  CPPUNIT_ASSERT ( ! child2->hasParent() );
+  CPPUNIT_ASSERT_THROW ( obj2->addChild(child2), std::length_error );
+  CPPUNIT_ASSERT ( obj2->numOfChildren() == 1 );
+  obj2->setMaxChildren(2);
+  CPPUNIT_ASSERT ( ! child2->hasParent() );
+  CPPUNIT_ASSERT ( obj2->getMaxChildren() == 2 );
+  obj2->addChild(child2);
+  CPPUNIT_ASSERT ( child2->hasParent() );
+  CPPUNIT_ASSERT ( obj2->hasChildren() );
+  CPPUNIT_ASSERT ( obj2->numOfChildren() == 2 );
+
+  delete obj1;
+  delete obj2;  // also deletes the child object
 }
 
 //----------------------------------------------------------------------
@@ -456,7 +475,7 @@ void FObjectTest::iteratorTest()
   finalcut::FObject::const_iterator c_iter, c_last;
   c_iter = obj->begin();
   c_last = obj->end();
-  int i = 0;
+  std::size_t i = 0;
 
   while ( c_iter != c_last )
   {