Changed external functions to enable global installation

* up until now all external functions were locally installed to a specific XalanTransformer instance contained within a TransformationGuard instance
** this had to change as I planned to add a "execute-transformation" function based on TransformationGuard which would have led to recursive self-instantiation
** global external functions have to be thread-safe
* as global external function can not be provided with a reference to a transformation-specific FilesystemFacade instance, the working path is now determined using xalan::Locator
** currently using pointer arithmetics on XMLCh* to remove the "file://" prefix of the URI returned by locator->getSystemId(), may be unsafe
* added compilation unit for PlattformGuard as it now contains function installation in addition to plattform lifetime management

11 files changed, 83 insertions, 66 deletions

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 02a9b79..fd14740 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -13,6 +13,7 @@ include_directories(
 add_executable(
 	test
 	test.cc
+	src/plattform_guard.cc
 	src/transformation_facade.cc
 	src/function/read_file.cc
 	src/function/read_xml_file.cc
diff --git a/src/function/read_directory.cc b/src/function/read_directory.cc
index f155029..b13be2b 100644
--- a/src/function/read_directory.cc
+++ b/src/function/read_directory.cc
@@ -6,21 +6,27 @@
 #include <xercesc/dom/DOMText.hpp>
 
 #include "support/xerces_string_guard.h"
+#include "support/filesystem_context.h"
 
 namespace InputXSLT {
 
-FunctionReadDirectory::FunctionReadDirectory(const FilesystemContext& context):
-	fs_context_(context),
+FunctionReadDirectory::FunctionReadDirectory():
 	document_cache_(std::make_shared<DomDocumentCache>()) { }
 
 xalan::XObjectPtr FunctionReadDirectory::execute(
 	xalan::XPathExecutionContext& executionContext,
 	xalan::XalanNode*,
 	const xalan::XObjectPtr argument,
-	const xalan::Locator*
+	const xalan::Locator* locator
 ) const {
+	const FilesystemContext fs_context(
+		boost::filesystem::path(
+			xercesc::XMLString::transcode(locator->getSystemId() + 7)
+		).parent_path().string()
+	);
+
 	const boost::filesystem::path directoryPath(
-		this->fs_context_.resolve(argument->str())
+		fs_context.resolve(argument->str())
 	);
 
 	DomDocumentCache::item* const cachedDocument(
@@ -37,7 +43,7 @@ xalan::XObjectPtr FunctionReadDirectory::execute(
 		);
 
 		if ( boost::filesystem::is_directory(directoryPath) ) {
-			this->fs_context_.iterate(
+			fs_context.iterate(
 				argument->str(),
 				[&domDocument, &rootNode](const boost::filesystem::path& p) {
 				xercesc::DOMElement* const itemNode(
diff --git a/src/function/read_directory.h b/src/function/read_directory.h
index f4f7ec8..02a0305 100644
--- a/src/function/read_directory.h
+++ b/src/function/read_directory.h
@@ -9,14 +9,13 @@
 #include <memory>
 
 #include "common.h"
-#include "support/filesystem_context.h"
 #include "support/dom/document_cache.h"
 
 namespace InputXSLT {
 
 class FunctionReadDirectory : public xalan::Function {
 	public:
-		FunctionReadDirectory(const FilesystemContext&);
+		FunctionReadDirectory();
 
 		virtual xalan::XObjectPtr execute(
 			xalan::XPathExecutionContext&,
@@ -31,7 +30,6 @@ class FunctionReadDirectory : public xalan::Function {
 		bool operator==(const FunctionReadDirectory&) const            = delete;
 
 	private:
-		const FilesystemContext& fs_context_;
 		std::shared_ptr<DomDocumentCache> document_cache_;
 
 		const xalan::XalanDOMString& getError(xalan::XalanDOMString&) const;
diff --git a/src/function/read_file.cc b/src/function/read_file.cc
index f531191..7634d54 100644
--- a/src/function/read_file.cc
+++ b/src/function/read_file.cc
@@ -8,6 +8,7 @@
 #include "boost/filesystem/fstream.hpp"
 
 #include "support/xerces_string_guard.h"
+#include "support/filesystem_context.h"
 
 namespace {
 
@@ -24,18 +25,23 @@ inline std::string readFile(const boost::filesystem::path& filePath) {
 
 namespace InputXSLT {
 
-FunctionReadFile::FunctionReadFile(const FilesystemContext& context):
-	fs_context_(context),
+FunctionReadFile::FunctionReadFile():
 	document_cache_(std::make_shared<DomDocumentCache>()) { }
 
 xalan::XObjectPtr FunctionReadFile::execute(
 	xalan::XPathExecutionContext& executionContext,
 	xalan::XalanNode*,
 	const xalan::XObjectPtr argument,
-	const xalan::Locator*
+	const xalan::Locator* locator
 ) const {
+	const FilesystemContext fs_context(
+		boost::filesystem::path(
+			xercesc::XMLString::transcode(locator->getSystemId() + 7)
+		).parent_path().string()
+	);
+
 	const boost::filesystem::path filePath(
-		this->fs_context_.resolve(argument->str())
+		fs_context.resolve(argument->str())
 	);
 
 	DomDocumentCache::item* const cachedDocument(
diff --git a/src/function/read_file.h b/src/function/read_file.h
index 6f38e95..65746a5 100644
--- a/src/function/read_file.h
+++ b/src/function/read_file.h
@@ -9,14 +9,13 @@
 #include <string>
 
 #include "common.h"
-#include "support/filesystem_context.h"
 #include "support/dom/document_cache.h"
 
 namespace InputXSLT {
 
 class FunctionReadFile : public xalan::Function {
 	public:
-		FunctionReadFile(const FilesystemContext&);
+		FunctionReadFile();
 
 		virtual xalan::XObjectPtr execute(
 			xalan::XPathExecutionContext&,
@@ -31,7 +30,6 @@ class FunctionReadFile : public xalan::Function {
 		bool operator==(const FunctionReadFile&) const       = delete;
 
 	private:
-		const FilesystemContext& fs_context_;
 		std::shared_ptr<DomDocumentCache> document_cache_;
 
 		const xalan::XalanDOMString& getError(xalan::XalanDOMString&) const;
diff --git a/src/function/read_xml_file.cc b/src/function/read_xml_file.cc
index bf9ec2e..608e71a 100644
--- a/src/function/read_xml_file.cc
+++ b/src/function/read_xml_file.cc
@@ -9,6 +9,7 @@
 #include "boost/filesystem/fstream.hpp"
 
 #include "support/xerces_string_guard.h"
+#include "support/filesystem_context.h"
 
 namespace {
 
@@ -30,18 +31,23 @@ inline xercesc::DOMNode* importDocumentElement(
 
 namespace InputXSLT {
 
-FunctionReadXmlFile::FunctionReadXmlFile(const FilesystemContext& context):
-	fs_context_(context),
+FunctionReadXmlFile::FunctionReadXmlFile():
 	document_cache_(std::make_shared<DomDocumentCache>()) { }
 
 xalan::XObjectPtr FunctionReadXmlFile::execute(
 	xalan::XPathExecutionContext& executionContext,
 	xalan::XalanNode*,
 	const xalan::XObjectPtr argument,
-	const xalan::Locator*
+	const xalan::Locator* locator
 ) const {
+	const FilesystemContext fs_context(
+		boost::filesystem::path(
+			xercesc::XMLString::transcode(locator->getSystemId() + 7)
+		).parent_path().string()
+	);
+
 	const boost::filesystem::path filePath(
-		this->fs_context_.resolve(argument->str())
+		fs_context.resolve(argument->str())
 	);
 
 	DomDocumentCache::item* const cachedDocument(
diff --git a/src/function/read_xml_file.h b/src/function/read_xml_file.h
index 1df48fb..d7ef440 100644
--- a/src/function/read_xml_file.h
+++ b/src/function/read_xml_file.h
@@ -10,14 +10,13 @@
 #include <memory>
 
 #include "common.h"
-#include "support/filesystem_context.h"
 #include "support/dom/document_cache.h"
 
 namespace InputXSLT {
 
 class FunctionReadXmlFile : public xalan::Function {
 	public:
-		FunctionReadXmlFile(const FilesystemContext&);
+		FunctionReadXmlFile();
 
 		virtual xalan::XObjectPtr execute(
 			xalan::XPathExecutionContext&,
@@ -32,7 +31,6 @@ class FunctionReadXmlFile : public xalan::Function {
 		bool operator==(const FunctionReadXmlFile&) const          = delete;
 
 	private:
-		const FilesystemContext& fs_context_;
 		std::shared_ptr<DomDocumentCache> document_cache_;
 
 		const xalan::XalanDOMString& getError(xalan::XalanDOMString& result) const;
diff --git a/src/plattform_guard.cc b/src/plattform_guard.cc
new file mode 100644
index 0000000..2c3cee4
--- /dev/null
+++ b/src/plattform_guard.cc
@@ -0,0 +1,46 @@
+#include "plattform_guard.h"
+
+#include <xalanc/Include/PlatformDefinitions.hpp>
+#include <xalanc/XalanTransformer/XalanTransformer.hpp>
+
+#include <xercesc/util/PlatformUtils.hpp>
+
+#include "common.h"
+#include "function/read_file.h"
+#include "function/read_xml_file.h"
+#include "function/read_directory.h"
+
+namespace InputXSLT {
+
+PlattformGuard::PlattformGuard() {
+	xercesc::XMLPlatformUtils::Initialize();
+	xalan::XalanTransformer::initialize();
+
+	const xalan::XalanDOMString customNamespace(
+		"function.inputxslt.application"
+	);
+
+	xalan::XalanTransformer::installExternalFunctionGlobal(
+		customNamespace,
+		xalan::XalanDOMString("read-file"),
+		InputXSLT::FunctionReadFile()
+	);
+
+	xalan::XalanTransformer::installExternalFunctionGlobal(
+		customNamespace,
+		xalan::XalanDOMString("read-xml-file"),
+		InputXSLT::FunctionReadXmlFile()
+	);
+
+	xalan::XalanTransformer::installExternalFunctionGlobal(
+		customNamespace,
+		xalan::XalanDOMString("read-directory"),
+		InputXSLT::FunctionReadDirectory()
+	);
+}
+
+PlattformGuard::~PlattformGuard() {
+	xalan::XalanTransformer::terminate();
+}
+
+}
diff --git a/src/plattform_guard.h b/src/plattform_guard.h
index fe8b954..12b19f0 100644
--- a/src/plattform_guard.h
+++ b/src/plattform_guard.h
@@ -1,24 +1,11 @@
 #ifndef INPUTXSLT_SRC_PLATTFORM_GUARD_H_
 #define INPUTXSLT_SRC_PLATTFORM_GUARD_H_
 
-#include <xalanc/Include/PlatformDefinitions.hpp>
-#include <xalanc/XalanTransformer/XalanTransformer.hpp>
-
-#include <xercesc/util/PlatformUtils.hpp>
-
-#include "common.h"
-
 namespace InputXSLT {
 
 struct PlattformGuard {
-	PlattformGuard() {
-		xercesc::XMLPlatformUtils::Initialize();
-		xalan::XalanTransformer::initialize();
-	}
-
-	~PlattformGuard() {
-		xalan::XalanTransformer::terminate();
-	}
+	PlattformGuard();
+	~PlattformGuard();
 };
 
 }
diff --git a/src/transformation_facade.cc b/src/transformation_facade.cc
index 3fee24f..91d761d 100644
--- a/src/transformation_facade.cc
+++ b/src/transformation_facade.cc
@@ -6,38 +6,11 @@
 #include <sstream>
 #include <iostream>
 
-#include "function/read_file.h"
-#include "function/read_xml_file.h"
-#include "function/read_directory.h"
-
 namespace InputXSLT {
 
 TransformationFacade::TransformationFacade(const std::string& transformation):
-	fs_context_(boost::filesystem::path(transformation).parent_path().string()),
 	transformation_{},
 	transformer_() {
-	const xalan::XalanDOMString customNamespace(
-		"function.inputxslt.application"
-	);
-
-	this->transformer_.installExternalFunction(
-		customNamespace,
-		xalan::XalanDOMString("read-file"),
-		InputXSLT::FunctionReadFile(this->fs_context_)
-	);
-
-	this->transformer_.installExternalFunction(
-		customNamespace,
-		xalan::XalanDOMString("read-xml-file"),
-		InputXSLT::FunctionReadXmlFile(this->fs_context_)
-	);
-
-	this->transformer_.installExternalFunction(
-		customNamespace,
-		xalan::XalanDOMString("read-directory"),
-		InputXSLT::FunctionReadDirectory(this->fs_context_)
-	);
-
 	this->transformer_.compileStylesheet(
 		xalan::XSLTInputSource(transformation.data()),
 		this->transformation_
diff --git a/src/transformation_facade.h b/src/transformation_facade.h
index 880335f..833016d 100644
--- a/src/transformation_facade.h
+++ b/src/transformation_facade.h
@@ -7,7 +7,6 @@
 #include <unordered_map>
 
 #include "common.h"
-#include "support/filesystem_context.h"
 
 namespace InputXSLT {
 
@@ -22,7 +21,6 @@ class TransformationFacade {
 		int generate(const std::string&, const parameter_map&);
 
 	private:
-		const FilesystemContext fs_context_;
 		const xalan::XalanCompiledStylesheet* transformation_;
 
 		xalan::XalanTransformer transformer_;