Add a mechanism for collections to be notified when an item is added

[libs/datafile.git] / source / collection.h

diff --git a/source/collection.h b/source/collection.h
index d0e8a1a8bb9b25c636ab23a8c1e4bbdcfa5c04a7..aa3c18a0fcc1a5e27f5d4ddc1278b58e65904877 100644 (file)
--- a/source/collection.h
+++ b/source/collection.h
@@ -3,6 +3,7 @@
 
 #include <msp/core/attributes.h>
 #include <msp/core/maputils.h>
+#include <msp/core/noncopyable.h>
 #include <msp/core/refptr.h>
 #include "collectionsource.h"
 #include "loader.h"
@@ -49,7 +50,7 @@ that are not present.  Items retrieted from the fallback collection are shared
 between the collections, and are only deleted when all collections in the chain
 have been destroyed.
 */
-class Collection
+class Collection: private NonCopyable
 {
 public:
        /**
@@ -91,8 +92,6 @@ private:
        SourceList sources;
        Collection *fallback;
 
-       Collection(const Collection &);
-       Collection &operator=(const Collection &);
 public:
        Collection();
        virtual ~Collection();
@@ -105,10 +104,11 @@ public:
                if(!item)
                        throw std::invalid_argument("Collection::add(item)");
 
-               RefPtr<typename RemoveConst<T>::Type> ptr(item);
+               typedef typename RemoveConst<T>::Type NCT;
+               RefPtr<NCT> ptr(item);
                try
                {
-                       insert_unique(items, name, ptr);
+                       add_var(name, get_type<NCT>(name), ptr);
                }
                catch(...)
                {
@@ -135,8 +135,28 @@ public:
                return extract<NCT>(get_var(name, get_type<NCT>(name)));
        }
 
+       /** Finds a typed object in the collection.  Returns null if the name does
+       not exist.  Throws if the name exists but the object is of an incorrect
+       type. */
+       template<typename T>
+       T *find(const std::string &name) const
+       {
+               ItemMap::const_iterator i = items.find(name);
+               return (i!=items.end() ? extract<typename RemoveConst<T>::Type>(i->second) : 0);
+       }
+
+       template<typename T>
+       T *find(const std::string &name)
+       {
+               typedef typename RemoveConst<T>::Type NCT;
+               const Variant *var = find_var(name, get_type<NCT>(name));
+               return (var ? &extract<NCT>(*var) : 0);
+       }
+
 private:
+       void add_var(const std::string &, const CollectionItemTypeBase *, const Variant &);
        const Variant &get_var(const std::string &, const CollectionItemTypeBase *);
+       const Variant *find_var(const std::string &, const CollectionItemTypeBase *);
 
        template<typename T>
        T &extract(const Variant &var) const;
@@ -279,10 +299,6 @@ public:
        object when done with it. */
        IO::Seekable *open_raw(const std::string &) const;
 
-protected:
-       // Deprecated.  Use open_raw instead.
-       DEPRECATED IO::Seekable *open_from_sources(const std::string &n) { return open_raw(n); }
-
 private:
        void gather_names_from_sources(std::list<std::string> &, const CollectionItemTypeBase &) const;
 
@@ -349,6 +365,7 @@ public:
        virtual bool can_create() const = 0;
        virtual void create_item(Collection &, const std::string &) const = 0;
        virtual void load_item(Collection &, Parser &, const std::string &) const = 0;
+       virtual void notify_item(Collection &, const std::string &, const Variant &) const = 0;
 
        template<typename T>
        bool can_extract() const
@@ -398,6 +415,26 @@ private:
                { return (dynamic_cast<C &>(coll).*func)(name); }
        };
 
+       struct NotifyeeBase
+       {
+               virtual ~NotifyeeBase() { }
+
+               virtual void notify(Collection &, const std::string &, T &) const = 0;
+       };
+
+       template<typename C>
+       struct Notifyee: NotifyeeBase
+       {
+               typedef void (C::*FuncPtr)(const std::string &, T &);
+
+               FuncPtr func;
+
+               Notifyee(FuncPtr f): func(f) { }
+
+               virtual void notify(Collection &coll, const std::string &name, T &item) const
+               { (dynamic_cast<C &>(coll).*func)(name, item); }
+       };
+
        template<typename B>
        struct Extractor: CollectionItemTypeBase::Extractor<B>
        {
@@ -406,6 +443,7 @@ private:
        };
 
        CreatorBase *creat;
+       std::vector<NotifyeeBase *> notif;
 
 public:
        CollectionItemType():
@@ -415,6 +453,8 @@ public:
        ~CollectionItemType()
        {
                delete creat;
+               for(typename std::vector<NotifyeeBase *>::const_iterator i=notif.begin(); i!=notif.end(); ++i)
+                       delete *i;
        }
 
        /** Sets a datafile keyword for this item type.  The Collection's loader
@@ -458,6 +498,13 @@ public:
                return *this;
        }
 
+       template<typename C>
+       CollectionItemType &notify(void (C::*func)(const std::string &, T &))
+       {
+               notif.push_back(new Notifyee<C>(func));
+               return *this;
+       }
+
        virtual bool is_same_type(const CollectionItemTypeBase &other) const
        { return dynamic_cast<const CollectionItemType<T> *>(&other); }
 
@@ -483,6 +530,13 @@ public:
        {
                throw std::runtime_error("this type cannot be loaded");
        }
+
+       virtual void notify_item(Collection &coll, const std::string &name, const Variant &var) const
+       {
+               RefPtr<T> obj = var.value<RefPtr<T> >();
+               for(typename std::vector<NotifyeeBase *>::const_iterator i=notif.begin(); i!=notif.end(); ++i)
+                       (*i)->notify(coll, name, *obj);
+       }
 };