gras: formalize the weak container api w/ docs

address issue #69, we now have a set_container call,
which is now formally part of the api.

Anyone can call set_container for custom container types.
GRAS supports shared ptr and pyobject out of the box.

5 files changed, 25 insertions, 2 deletions

diff --git a/lib/CMakeLists.txt b/lib/CMakeLists.txt
index ff36a5a..5d059e7 100644
--- a/lib/CMakeLists.txt
+++ b/lib/CMakeLists.txt
@@ -58,6 +58,7 @@ list(APPEND GRAS_SOURCES
     ${CMAKE_CURRENT_SOURCE_DIR}/top_block_query.cpp
     ${CMAKE_CURRENT_SOURCE_DIR}/register_messages.cpp
     ${CMAKE_CURRENT_SOURCE_DIR}/theron_allocator.cpp
+    ${CMAKE_CURRENT_SOURCE_DIR}/weak_container.cpp
 )
 
 ########################################################################
diff --git a/lib/element.cpp b/lib/element.cpp
index 989c184..dfc3f57 100644
--- a/lib/element.cpp
+++ b/lib/element.cpp
@@ -48,6 +48,11 @@ ElementImpl::~ElementImpl(void)
     if (this->block) this->block_cleanup();
 }
 
+void Element::set_container(WeakContainer *container)
+{
+    (*this)->weak_self.reset(container);
+}
+
 bool Element::equals(const Element &rhs)
 {
     return this->get() == rhs.get();
diff --git a/lib/element_impl.hpp b/lib/element_impl.hpp
index 869006e..3148d93 100644
--- a/lib/element_impl.hpp
+++ b/lib/element_impl.hpp
@@ -29,6 +29,7 @@ struct ElementImpl
     std::string name;
     long unique_id;
     std::string id;
+    boost::shared_ptr<WeakContainer> weak_self;
 
     //top block stuff
     SharedThreadGroup thread_group;
diff --git a/lib/hier_block.cpp b/lib/hier_block.cpp
index d8756a4..758af0c 100644
--- a/lib/hier_block.cpp
+++ b/lib/hier_block.cpp
@@ -40,9 +40,10 @@ void HierBlock::disconnect(const Element &elem)
 
 static Apology::Wax get_ref(const Element &elem)
 {
-    if (elem.weak_self)
+    boost::shared_ptr<WeakContainer> weak_self = elem->weak_self;
+    if (weak_self)
     {
-        boost::shared_ptr<const void> shared_self = elem.weak_self->lock();
+        boost::shared_ptr<const void> shared_self = weak_self->lock();
         if (shared_self) return shared_self;
     }
     return elem;
diff --git a/lib/weak_container.cpp b/lib/weak_container.cpp
new file mode 100644
index 0000000..192a2fd
--- /dev/null
+++ b/lib/weak_container.cpp
@@ -0,0 +1,15 @@
+// Copyright (C) by Josh Blum. See LICENSE.txt for licensing information.
+
+#include <gras/weak_container.hpp>
+
+using namespace gras;
+
+WeakContainer::WeakContainer(void)
+{
+    //NOP
+}
+
+WeakContainer::~WeakContainer(void)
+{
+    //NOP
+}