Switched internal DomDocumentCache structure to std::stack

* using std::unordered_map for named cache lookups was a nice idea but is not useful when one keeps in mind that:
** we don't want cached external function responses in a situation where we are able to execute transformations inside transformations
** cached responses mean that we can not read a xml file, overwrite it using another transformation and then read it again
* the currently available InputXSLT frontend only processes a single transformation anyway, so increased memory requirements should not pose a problem
** if a future frontend should offer batch processing of transformation tasks, one could implement a cache reset method to free memory after a transformation has been processed

1 files changed, 3 insertions, 7 deletions

diff --git a/src/support/dom/document_cache.h b/src/support/dom/document_cache.h
index cbac5c7..1f9a9e3 100644
--- a/src/support/dom/document_cache.h
+++ b/src/support/dom/document_cache.h
@@ -5,9 +5,8 @@
 
 #include <xercesc/dom/DOMDocument.hpp>
 
-#include <string>
 #include <mutex>
-#include <unordered_map>
+#include <stack>
 #include <memory>
 
 #include "common.h"
@@ -16,18 +15,15 @@ namespace InputXSLT {
 
 class DomDocumentCache {
 	public:
-		typedef std::pair<bool, xalan::XalanDocument*> optional_item;
-
 		DomDocumentCache();
 
-		optional_item get(const std::string&);
-		optional_item create(const std::string&, xercesc::DOMDocument*);
+		xalan::XalanDocument* create(xercesc::DOMDocument*);
 
 	private:
 		class item;
 
 		std::mutex write_mutex_;
-		std::unordered_map<std::string, std::unique_ptr<item>> map_;
+		std::stack<std::unique_ptr<item>> cache_;
 
 };