Implemented custom xercesc::DOMDocument deleter

* pointers to xercesc::DOMDocument were manually released
** this is now solved using a custom deleter for the appropriate std::unqiue_ptr template specialization
* added matching factory method to DomDocumentCache
* updated external function implementations accordingly
** "constructDocument" is now expected to return a DomDocumentCache::document_ptr instance
* updated TransformerFacade accordingly
* this change was implemented to get rid of the manual memory management required by xalan / xerces

4 files changed, 45 insertions, 14 deletions

diff --git a/src/support/dom/document_cache.cc b/src/support/dom/document_cache.cc
index 0ad540c..23805b5 100644
--- a/src/support/dom/document_cache.cc
+++ b/src/support/dom/document_cache.cc
@@ -1,19 +1,43 @@
 #include "document_cache.h"
 
+#include <xercesc/dom/DOMDocument.hpp>
+#include <xercesc/dom/DOMImplementation.hpp>
+
 #include <stdexcept>
 
+#include "support/xerces_string_guard.h"
+
 namespace InputXSLT {
 
+auto DomDocumentCache::createDocument() -> document_ptr {
+	return document_ptr(
+		xercesc::DOMImplementation::getImplementation()->createDocument(
+			nullptr,
+			*XercesStringGuard<XMLCh>("content"),
+			nullptr
+		)
+	);
+}
+
 DomDocumentCache::DomDocumentCache():
 	write_mutex_(),
 	cache_() { }
 
-xalan::XalanDocument* DomDocumentCache::create(xercesc::DOMDocument* document) {
+xalan::XalanDocument* DomDocumentCache::create(document_ptr&& document) {
 	std::lock_guard<std::mutex> guard(this->write_mutex_);
 
-	this->cache_.emplace(new item(document));
+	this->cache_.emplace(
+		new item(
+			std::move(document)
+		)
+	);
 
 	return this->cache_.top()->getXalanDocument();
 }
 
+void DomDocumentCache::document_deleter::operator()(
+	xercesc::DOMDocument* document) {
+	document->release();
+}
+
 }
diff --git a/src/support/dom/document_cache.h b/src/support/dom/document_cache.h
index 1f9a9e3..3aeb332 100644
--- a/src/support/dom/document_cache.h
+++ b/src/support/dom/document_cache.h
@@ -14,10 +14,23 @@
 namespace InputXSLT {
 
 class DomDocumentCache {
+	class document_deleter {
+		friend std::unique_ptr<xercesc::DOMDocument, document_deleter>;
+
+		void operator()(xercesc::DOMDocument*);
+	};
+
 	public:
+		typedef std::unique_ptr<
+			xercesc::DOMDocument,
+			document_deleter
+		> document_ptr;
+
+		static document_ptr createDocument();
+
 		DomDocumentCache();
 
-		xalan::XalanDocument* create(xercesc::DOMDocument*);
+		xalan::XalanDocument* create(document_ptr&&);
 
 	private:
 		class item;
diff --git a/src/support/dom/document_cache_item.cc b/src/support/dom/document_cache_item.cc
index 9798bfa..a684d97 100644
--- a/src/support/dom/document_cache_item.cc
+++ b/src/support/dom/document_cache_item.cc
@@ -2,20 +2,16 @@
 
 namespace InputXSLT {
 
-DomDocumentCache::item::item(xercesc::DOMDocument* document):
+DomDocumentCache::item::item(document_ptr&& document):
+	document_(std::move(document)),
 	parser_(),
 	dom_support_(parser_),
-	document_(document),
 	parsed_source_(
-		document_,
+		document_.get(),
 		parser_,
 		dom_support_
 	) { }
 
-DomDocumentCache::item::~item() {
-	this->document_->release();
-}
-
 xalan::XalanDocument* DomDocumentCache::item::getXalanDocument() {
 	return this->parsed_source_.getDocument();
 }
diff --git a/src/support/dom/document_cache_item.h b/src/support/dom/document_cache_item.h
index 13fddfc..ebc9172 100644
--- a/src/support/dom/document_cache_item.h
+++ b/src/support/dom/document_cache_item.h
@@ -14,19 +14,17 @@ namespace InputXSLT {
 
 class DomDocumentCache::item {
 	public:
-		~item();
-
 		xalan::XalanDocument* getXalanDocument();
 
 	protected:
 		friend DomDocumentCache;
 
-		item(xercesc::DOMDocument*);
+		item(document_ptr&&);
 
 	private:
+		document_ptr document_;
 		xalan::XercesParserLiaison parser_;
 		xalan::XercesDOMSupport dom_support_;
-		xercesc::DOMDocument* const document_;
 		xalan::XercesDOMWrapperParsedSource parsed_source_;
 
 };