Implemented ErrorMultiplexer as primary error handler

* ErrorMultiplexer is derived from both xercesc::ErrorHandler and xalan::ProblemListener
* registers itself as XalanTransformer's ErrorHandler and ProblemListener
* distributes captured errors and warnings to all registered ErrorMultiplexer::Receiver instances
** ErrorCapacitor implements the ErrorMultiplexer::Receiver interface and as such registers itself in a given ErrorMultiplexer instance
** ErrorMultiplexer reduces the different xalan and xercesc internal error classifications into either warnings or errors
* this was implemented to make it possible to easily differentiate between warnings and errors
** previously warnings were treated as errors
** ErrorCapacitor ignores warnings and only captures errors
** WarningCapacitor will be implemented to handle warnings during XSLT processing

4 files changed, 337 insertions, 0 deletions

diff --git a/src/support/error/error_capacitor.cc b/src/support/error/error_capacitor.cc
new file mode 100644
index 0000000..58cfb81
--- /dev/null
+++ b/src/support/error/error_capacitor.cc
@@ -0,0 +1,37 @@
+#include "error_capacitor.h"
+
+namespace InputXSLT {
+
+ErrorCapacitor::ErrorCapacitor(ErrorMultiplexer* multiplexer):
+	multiplexer_(multiplexer),
+	error_cache_(new error_cache()) {
+	this->multiplexer_->connectReceiver(this);
+}
+
+ErrorCapacitor::~ErrorCapacitor() {
+	this->multiplexer_->disconnectReceiver(this);
+}
+
+void ErrorCapacitor::discharge() {
+	if ( !this->error_cache_->empty() ) {
+		throw exception(std::move(this->error_cache_));
+	}
+}
+
+void ErrorCapacitor::receive(
+	const ErrorMultiplexer::ErrorType type,
+	const std::string& message
+) {
+	if ( type == ErrorMultiplexer::ErrorType::Error ) {
+		this->error_cache_->emplace_back(message);
+	}
+}
+
+ErrorCapacitor::exception::exception(error_cache_ptr ptr):
+	error_cache_(std::move(ptr)) { }
+
+auto ErrorCapacitor::exception::getCachedErrors() const -> const error_cache* {
+	return this->error_cache_.get();
+}
+
+}
diff --git a/src/support/error/error_capacitor.h b/src/support/error/error_capacitor.h
new file mode 100644
index 0000000..6017cb4
--- /dev/null
+++ b/src/support/error/error_capacitor.h
@@ -0,0 +1,46 @@
+#ifndef INPUTXSLT_SRC_SUPPORT_ERROR_ERROR_CAPACITOR_H_
+#define INPUTXSLT_SRC_SUPPORT_ERROR_ERROR_CAPACITOR_H_
+
+#include <memory>
+
+#include "error_multiplexer.h"
+
+namespace InputXSLT {
+
+class ErrorCapacitor : public ErrorMultiplexer::Receiver {
+	public:
+		class exception;
+
+		typedef std::vector<std::string> error_cache;
+		typedef std::unique_ptr<error_cache> error_cache_ptr;
+
+		ErrorCapacitor(ErrorMultiplexer*);
+		~ErrorCapacitor();
+
+		void discharge();
+
+		virtual void receive(
+			const ErrorMultiplexer::ErrorType,
+			const std::string&
+		);
+
+	private:
+		ErrorMultiplexer* const multiplexer_;
+		error_cache_ptr error_cache_;
+
+};
+
+class ErrorCapacitor::exception {
+	public:
+		exception(error_cache_ptr);
+
+		const error_cache* getCachedErrors() const;
+
+	private:
+		error_cache_ptr error_cache_;
+
+};
+
+}
+
+#endif  // INPUTXSLT_SRC_SUPPORT_ERROR_ERROR_CAPACITOR_H_
diff --git a/src/support/error/error_multiplexer.cc b/src/support/error/error_multiplexer.cc
new file mode 100644
index 0000000..f5d4e0f
--- /dev/null
+++ b/src/support/error/error_multiplexer.cc
@@ -0,0 +1,170 @@
+#include "error_multiplexer.h"
+
+#include <xercesc/sax/SAXParseException.hpp>
+
+#include <xalanc/PlatformSupport/DOMStringPrintWriter.hpp>
+
+#include <algorithm>
+
+#include "support/xalan_string.h"
+#include "support/xerces_string_guard.h"
+
+namespace {
+
+using InputXSLT::XercesStringGuard;
+using InputXSLT::ErrorMultiplexer;
+
+inline std::string getMessage(const xercesc::SAXParseException& exception) {
+	return (
+		std::string(*XercesStringGuard<char>(exception.getMessage()))
+		+ ". (Occurred in entity '"
+		+ std::string(*XercesStringGuard<char>(exception.getSystemId()))
+		+ "', at line "
+		+ std::to_string(exception.getLineNumber())
+		+ ", column "
+		+ std::to_string(exception.getColumnNumber())
+		+ ".)"
+	);
+}
+
+inline ErrorMultiplexer::ErrorType toErrorType(
+	const xalan::ProblemListenerBase::eClassification classification) {
+	switch ( classification ) {
+		case xalan::ProblemListenerBase::eClassification::eMessage ||
+		     xalan::ProblemListenerBase::eClassification::eWarning: {
+			return ErrorMultiplexer::ErrorType::Warning;
+		}
+		default: {
+			return ErrorMultiplexer::ErrorType::Error;
+		}
+	}
+}
+
+}
+
+namespace InputXSLT {
+
+ErrorMultiplexer::ErrorMultiplexer(xalan::XalanTransformer* transformer):
+	transformer_(transformer),
+	receivers_() {
+	this->transformer_->setErrorHandler(this);
+	this->transformer_->setProblemListener(this);
+}
+
+ErrorMultiplexer::~ErrorMultiplexer() {
+	this->transformer_->setErrorHandler(nullptr);
+	this->transformer_->setProblemListener(nullptr);
+}
+
+void ErrorMultiplexer::connectReceiver(Receiver* receiver) {
+	this->receivers_.push_back(receiver);
+}
+
+void ErrorMultiplexer::disconnectReceiver(Receiver* receiver) {
+	this->receivers_.erase(
+		std::remove(
+			this->receivers_.begin(),
+			this->receivers_.end(),
+			receiver
+		)
+	);
+}
+
+void ErrorMultiplexer::warning(const xercesc::SAXParseException& exception) {
+	this->multiplex(
+		ErrorType::Warning,
+		"Warning: " + getMessage(exception)
+	);
+}
+
+void ErrorMultiplexer::error(const xercesc::SAXParseException& exception) {
+	this->multiplex(
+		ErrorType::Error,
+		"Error: " + getMessage(exception)
+	);
+}
+
+void ErrorMultiplexer::fatalError(const xercesc::SAXParseException& exception) {
+	this->multiplex(
+		ErrorType::Error,
+		"Fatal error: " + getMessage(exception)
+	);
+}
+
+void ErrorMultiplexer::resetErrors() { }
+
+void ErrorMultiplexer::problem(
+	xalan::ProblemListenerBase::eSource         source,
+	xalan::ProblemListenerBase::eClassification classification,
+	const xalan::XalanDOMString&                message,
+	const xalan::Locator*                       locator,
+	const xalan::XalanNode*                     node
+) {
+	xalan::XalanDOMString problemSummary;
+	xalan::DOMStringPrintWriter writer(problemSummary);
+
+	defaultFormat(
+		writer,
+		source,
+		classification,
+		message,
+		locator,
+		node
+	);
+
+	this->multiplex(
+		toErrorType(classification),
+		toString(problemSummary)
+	);
+}
+
+void ErrorMultiplexer::problem(
+	xalan::ProblemListenerBase::eSource         source,
+	xalan::ProblemListenerBase::eClassification classification,
+	const xalan::XalanDOMString&                message,
+	const xalan::XalanNode*                     node
+) {
+	xalan::XalanDOMString problemSummary;
+	xalan::DOMStringPrintWriter writer(problemSummary);
+
+	defaultFormat(
+		writer,
+		source,
+		classification,
+		message,
+		node
+	);
+
+	this->multiplex(
+		toErrorType(classification),
+		toString(problemSummary)
+	);
+}
+
+void ErrorMultiplexer::problem(
+	xalan::ProblemListenerBase::eSource,
+	xalan::ProblemListenerBase::eClassification,
+	const xalan::XalanNode*,
+	const xalan::ElemTemplateElement*,
+	const xalan::XalanDOMString&,
+	const xalan::XalanDOMChar*,
+	xalan::XalanFileLoc,
+	xalan::XalanFileLoc
+) { }
+
+void ErrorMultiplexer::setPrintWriter(xalan::PrintWriter*) { }
+
+void ErrorMultiplexer::multiplex(
+	const ErrorType type,
+	const std::string& message
+) {
+	std::for_each(
+		this->receivers_.begin(),
+		this->receivers_.end(),
+		[&type, &message](Receiver* const receiver) -> void {
+			receiver->receive(type, message);
+		}
+	);
+}
+
+}
diff --git a/src/support/error/error_multiplexer.h b/src/support/error/error_multiplexer.h
new file mode 100644
index 0000000..02cfaf8
--- /dev/null
+++ b/src/support/error/error_multiplexer.h
@@ -0,0 +1,84 @@
+#ifndef INPUTXSLT_SRC_SUPPORT_ERROR_ERROR_MULTIPLEXER_H_
+#define INPUTXSLT_SRC_SUPPORT_ERROR_ERROR_MULTIPLEXER_H_
+
+#include <xercesc/sax/ErrorHandler.hpp>
+
+#include <xalanc/XSLT/ProblemListener.hpp>
+#include <xalanc/XalanTransformer/XalanTransformer.hpp>
+
+#include <vector>
+#include <string>
+
+#include "common.h"
+
+namespace InputXSLT {
+
+class ErrorMultiplexer : public xercesc::ErrorHandler,
+                         public xalan::ProblemListener {
+	public:
+		enum class ErrorType;
+		struct Receiver;
+
+		ErrorMultiplexer(xalan::XalanTransformer*);
+		~ErrorMultiplexer();
+
+		void connectReceiver(Receiver*);
+		void disconnectReceiver(Receiver*);
+
+		virtual void warning(const xercesc::SAXParseException&);
+		virtual void error(const xercesc::SAXParseException&);
+		virtual void fatalError(const xercesc::SAXParseException&);
+		virtual void resetErrors();
+
+		virtual void problem(
+			xalan::ProblemListenerBase::eSource,
+			xalan::ProblemListenerBase::eClassification,
+			const xalan::XalanDOMString&,
+			const xalan::Locator*,
+			const xalan::XalanNode*
+		);
+
+		virtual void problem(
+			xalan::ProblemListenerBase::eSource,
+			xalan::ProblemListenerBase::eClassification,
+			const xalan::XalanDOMString&,
+			const xalan::XalanNode*
+		);
+
+		virtual void problem(
+			xalan::ProblemListenerBase::eSource,
+			xalan::ProblemListenerBase::eClassification,
+			const xalan::XalanNode*,
+			const xalan::ElemTemplateElement*,
+			const xalan::XalanDOMString&,
+			const xalan::XalanDOMChar*,
+			xalan::XalanFileLoc,
+			xalan::XalanFileLoc
+		);
+
+		virtual void setPrintWriter(xalan::PrintWriter*);
+
+	private:
+		xalan::XalanTransformer* const transformer_;
+
+		std::vector<Receiver*> receivers_;
+
+		void multiplex(const ErrorType, const std::string&);
+
+};
+
+enum class ErrorMultiplexer::ErrorType {
+	Warning,
+	Error
+};
+
+struct ErrorMultiplexer::Receiver {
+	virtual void receive(
+		const ErrorMultiplexer::ErrorType,
+		const std::string&
+	) = 0;
+};
+
+}
+
+#endif  // INPUTXSLT_SRC_SUPPORT_ERROR_ERROR_MULTIPLEXER_H_