Implemented external "generate" function

* this function essentially provides the same functionality as FunctionTransform with the addition of directly committing the result to the filesystem
** this is needed if one wants to generate doctype-containing transformations from inside a transformation as "write-file" is not able to infer the doctype of a given xalan::XalanNode pointer
** this is a integral limitation of (at least) XSLT 1.0 as implemented in Apache Xalan
*** a document can of course only have a single document type
*** e.g. we can not include a doctype node in the result tree of FunctionTransform
* implemented test case for FunctionGenerate
* transformation "test.xsl" is shared between the FunctionTransform and FunctionGenerate test cases
* modified README.md accordingly

4 files changed, 111 insertions, 1 deletions

diff --git a/src/function/base.h b/src/function/base.h
index c3e1fb6..2d1e4c4 100644
--- a/src/function/base.h
+++ b/src/function/base.h
@@ -93,7 +93,7 @@ class FunctionBase : public xalan::Function {
 		template <std::size_t... Index>
 		inline xalan::XalanDocument* callConstructDocument(
 			const XObjectArgVectorType& parameters,
-			const xalan::Locator* locator,
+			const xalan::Locator*       locator,
 			Sequence<Index...>
 		) const {
 			XObjectValue valueGetter(
diff --git a/src/function/generate.cc b/src/function/generate.cc
new file mode 100644
index 0000000..4ece322
--- /dev/null
+++ b/src/function/generate.cc
@@ -0,0 +1,71 @@
+#include "generate.h"
+
+#include <xalanc/PlatformSupport/XalanOutputStreamPrintWriter.hpp>
+#include <xalanc/PlatformSupport/XalanStdOutputStream.hpp>
+#include <xalanc/XMLSupport/FormatterToXML.hpp>
+
+#include <boost/filesystem.hpp>
+#include <boost/filesystem/fstream.hpp>
+
+#include "transformer_facade.h"
+#include "support/xerces_string_guard.h"
+#include "support/dom/result_node_facade.h"
+#include "support/error/error_capacitor.h"
+
+namespace InputXSLT {
+
+DomDocumentCache::document_ptr FunctionGenerate::constructDocument(
+	xalan::XSLTInputSource  inputSource,
+	xalan::XSLTInputSource  transformationSource,
+	boost::filesystem::path targetPath
+) const {
+	DomDocumentCache::document_ptr domDocument(
+		DomDocumentCache::createDocument("content")
+	);
+
+	ResultNodeFacade result(domDocument.get(), "generation");
+	result.setAttribute("path", targetPath.string());
+
+	boost::filesystem::ofstream file(targetPath);
+
+	if ( file.is_open() ) {
+		TransformerFacade transformer(this->include_resolver_);
+
+		try {
+			xalan::XalanStdOutputStream         output(file);
+			xalan::XalanOutputStreamPrintWriter writer(output);
+			xalan::FormatterToXML               targetFormatter(writer);
+
+			targetFormatter.setDoIndent(true);
+
+			transformer.generate(
+				inputSource,
+				transformationSource,
+				targetFormatter
+			);
+
+			result.setAttribute("result", "success");
+		}
+		catch (const ErrorCapacitor::exception& exception) {
+			result.setAttribute("result", "error");
+
+			for ( auto&& error : *exception ) {
+				result.setValueNode("error", error);
+			}
+		}
+
+		WarningCapacitor::warning_cache_ptr warnings(
+			transformer.getCachedWarnings()
+		);
+
+		for ( auto&& warning : *warnings ) {
+			result.setValueNode("warning", warning);
+		}
+	} else {
+		result.setAttribute("result", "error");
+	}
+
+	return domDocument;
+}
+
+}
diff --git a/src/function/generate.h b/src/function/generate.h
new file mode 100644
index 0000000..43f5da1
--- /dev/null
+++ b/src/function/generate.h
@@ -0,0 +1,32 @@
+#ifndef INPUTXSLT_SRC_FUNCTION_GENERATE_H_
+#define INPUTXSLT_SRC_FUNCTION_GENERATE_H_
+
+#include <xalanc/XSLT/XSLTInputSource.hpp>
+
+#include "base.h"
+
+namespace InputXSLT {
+
+class FunctionGenerate : public FunctionBase<
+	FunctionGenerate,
+	xalan::XSLTInputSource,
+	xalan::XSLTInputSource,
+	boost::filesystem::path
+> {
+	public:
+		using FunctionBase::FunctionBase;
+
+	protected:
+		friend FunctionBase;
+
+		DomDocumentCache::document_ptr constructDocument(
+			xalan::XSLTInputSource,
+			xalan::XSLTInputSource,
+			boost::filesystem::path
+		) const;
+
+};
+
+}
+
+#endif  // INPUTXSLT_SRC_FUNCTION_GENERATE_H_
diff --git a/src/plattform_guard.cc b/src/plattform_guard.cc
index cc3c9c0..5d19e32 100644
--- a/src/plattform_guard.cc
+++ b/src/plattform_guard.cc
@@ -10,6 +10,7 @@
 #include "function/write_file.h"
 #include "function/read_directory.h"
 #include "function/transform.h"
+#include "function/generate.h"
 #include "function/external_text_formatter.h"
 
 namespace InputXSLT {
@@ -49,6 +50,12 @@ PlattformGuard::PlattformGuard(const std::vector<std::string>& path):
 
 	xalan::XalanTransformer::installExternalFunctionGlobal(
 		customNamespace,
+		xalan::XalanDOMString("generate"),
+		InputXSLT::FunctionGenerate(&this->include_resolver_)
+	);
+
+	xalan::XalanTransformer::installExternalFunctionGlobal(
+		customNamespace,
 		xalan::XalanDOMString("external-text-formatter"),
 		InputXSLT::FunctionExternalTextFormatter(&this->include_resolver_)
 	);