From c3c97f2956d3546d28ad7f036462dd2401a3bab1 Mon Sep 17 00:00:00 2001
From: James Turner <zakalawe@mac.com>
Date: Sat, 20 Nov 2010 03:31:42 -0800
Subject: [PATCH] Shrink PropertyObjectBase by a pointer, don't pull exception
 header into the header.

---
 simgear/props/propertyObject.cxx      | 42 +++++++++++++++++++++------
 simgear/props/propertyObject.hxx      | 32 ++++++++++----------
 simgear/props/propertyObject_test.cxx | 21 ++++++++++++++
 3 files changed, 71 insertions(+), 24 deletions(-)

diff --git a/simgear/props/propertyObject.cxx b/simgear/props/propertyObject.cxx
index 0685ae91..3eea0ac2 100644
--- a/simgear/props/propertyObject.cxx
+++ b/simgear/props/propertyObject.cxx
@@ -21,6 +21,8 @@
 
 #include "propertyObject.hxx"
 
+#include <simgear/structure/exception.hxx>
+
 namespace simgear
 {
 
@@ -32,7 +34,6 @@ void PropertyObjectBase::setDefaultRoot(SGPropertyNode* aRoot)
 }
 
 PropertyObjectBase::PropertyObjectBase(const PropertyObjectBase& aOther) :
-  _base(aOther._base),
   _path(aOther._path),
   _prop(aOther._prop)
 {
@@ -40,33 +41,56 @@ PropertyObjectBase::PropertyObjectBase(const PropertyObjectBase& aOther) :
 }
 
 PropertyObjectBase::PropertyObjectBase(const char* aChild) :
-  _base(NULL),
   _path(aChild),
   _prop(NULL)
 {
 }
   
 PropertyObjectBase::PropertyObjectBase(SGPropertyNode* aNode, const char* aChild) :
-  _base(aNode),
   _path(aChild),
-  _prop(NULL)
+  _prop(aNode)
 {
 
 }
   
 SGPropertyNode* PropertyObjectBase::node(bool aCreate) const
 {
-  if (_prop) {
+  if (_path == NULL) { // already resolved
     return _prop;
   }
   
-  _prop = _base ? _base : static_defaultRoot;
-  if (_path) {
-    _prop = _prop->getNode(_path, aCreate);
-  }
+  SGPropertyNode* r = _prop ? _prop : static_defaultRoot;
+  _prop = r->getNode(_path, aCreate);
   
+  if (_prop) {
+    // resolve worked, we will cache from now on, so clear _path
+    _path = NULL;
+  }
+
   return _prop;
 }
 
+SGPropertyNode* PropertyObjectBase::getOrThrow() const
+{
+  SGPropertyNode* n = node(false);
+  if (!n) {
+    std::string path;
+    if (_prop) {
+      path = _prop->getPath();
+      if (_path) {
+        path += '/';      
+      }
+    }
+
+    if (_path) {
+      path += _path;
+    }
+
+    throw sg_exception("Unknown property:" + path);
+  }
+
+  return n;
+}
+
 } // of namespace simgear
 
diff --git a/simgear/props/propertyObject.hxx b/simgear/props/propertyObject.hxx
index 7aeb0337..33921c7a 100644
--- a/simgear/props/propertyObject.hxx
+++ b/simgear/props/propertyObject.hxx
@@ -19,7 +19,6 @@
 #define SG_PROPERTY_OBJECT
 
 #include <simgear/props/props.hxx>
-#include <simgear/structure/exception.hxx>
 
 namespace simgear
 {
@@ -37,9 +36,20 @@ public:
   
   SGPropertyNode* node(bool aCreate) const;
 
+  /**
+   * Resolve the property node, or throw an exception if it could not
+   * be resolved.
+   */
+  SGPropertyNode* getOrThrow() const;
 protected:
-  SGPropertyNode* _base;
-  const char* _path;
+  mutable const char* _path;
+
+  /**
+   * Important - if _path is NULL, this is the actual prop.
+   * If path is non-NULL, this is the parent which path should be resolved
+   * against (or NULL, if _path is absolute). Use node() instead of accessing
+   * this directly, and the above is handled automatically. 
+   */
   mutable SGPropertyNode* _prop;
 };
 
@@ -94,12 +104,7 @@ public:
 // conversion operators
   operator T () const
   {
-    SGPropertyNode* n = node();
-    if (!n) {
-      throw sg_exception("read of undefined property:", _path);
-    }
-    
-    return n->getValue<T>();
+    return getOrThrow()->getValue<T>();
   }
 
   T operator=(const T& aValue)
@@ -142,12 +147,7 @@ public:
   
   operator std::string () const
   {
-    SGPropertyNode* n = node();
-    if (!n) {
-      throw sg_exception("read of undefined property:", _path);
-    }
-    
-    return n->getStringValue();
+    return getOrThrow()->getStringValue();
   }
   
   const char* operator=(const char* aValue)
@@ -193,9 +193,11 @@ private:
 
 } // of namespace simgear
 
+/*
 typedef simgear::PropertyObject<double> SGPropObjDouble;
 typedef simgear::PropertyObject<bool> SGPropObjBool;
 typedef simgear::PropertyObject<std::string> SGPropObjString;
 typedef simgear::PropertyObject<long> SGPropObjInt;
+*/
 
 #endif
diff --git a/simgear/props/propertyObject_test.cxx b/simgear/props/propertyObject_test.cxx
index 38e925e8..2b2ee1ec 100644
--- a/simgear/props/propertyObject_test.cxx
+++ b/simgear/props/propertyObject_test.cxx
@@ -7,12 +7,15 @@
 
 #include "propertyObject.hxx"
 
+#include <simgear/structure/exception.hxx>
+
 using std::cout;
 using std::cerr;
 using std::endl;
 
 using namespace simgear;
 
+
 SGPropertyNode* testRoot = NULL;
 
 bool testBasic()
@@ -41,6 +44,23 @@ bool testBasic()
   return true;
 }
 
+void testRelative()
+{
+  SGPropertyNode* n = testRoot->getNode("a");
+  assert(n);
+
+  PropertyObject<int> a1(n, "bar");
+  assert(a1 == 1234);
+
+  PropertyObject<int> a5(n, "some/child/path");
+  a5 = 4321;
+  assert(n->getIntValue("some/child/path") == 4321);
+
+  SGPropertyNode* m = testRoot->getNode("a/alice");
+  PropertyObject<std::string> a4(m);
+  assert(a4 == "aaaa");
+}
+
 void testString()
 {
   PropertyObject<std::string> sp("a/alice");
@@ -145,6 +165,7 @@ int main(int argc, char* argv[])
 		return EXIT_FAILURE;		
 	}
 
+  testRelative();
   testReadMissing();
   testString();
   testAssignment();
-- 
2.39.5