Refactored stuff surrounding the ResourceLocator class, implemented StaticResourceLocator which can be used for registering static resources (mainly for testing or if certain resources need to be available from the executable)

4 files changed, 422 insertions, 65 deletions

diff --git a/src/core/resource/Resource.cpp b/src/core/resource/Resource.cpp
index e69de29..349c82a 100644
--- a/src/core/resource/Resource.cpp
+++ b/src/core/resource/Resource.cpp
@@ -0,0 +1,46 @@
+/*
+    Ousía
+    Copyright (C) 2014, 2015  Benjamin Paaßen, Andreas Stöckel
+
+    This program is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#include "Resource.hpp"
+#include "ResourceLocator.hpp"
+
+namespace ousia {
+
+/* Class Resource */
+
+Resource::Resource()
+    : Resource(false, NullResourceLocator, ResourceType::UNKNOWN, "")
+{
+}
+
+Resource::Resource(bool valid, const ResourceLocator &locator,
+                   ResourceType type, const std::string &location)
+    : valid(valid), locator(&locator), type(type), location(location)
+{
+}
+
+std::unique_ptr<std::istream> Resource::stream() const
+{
+	return locator->stream(location);
+}
+
+/* NullResource instance */
+
+const Resource NullResource{};
+}
+
diff --git a/src/core/resource/Resource.hpp b/src/core/resource/Resource.hpp
index 9df851d..1934029 100644
--- a/src/core/resource/Resource.hpp
+++ b/src/core/resource/Resource.hpp
@@ -22,15 +22,159 @@
  * Contains the Resource class, representing an external resource as well as
  * further types used for describing resources.
  *
+ * @author Benjamin Paaßen (bpassen@techfak.uni-bielefeld.de)
  */
 
 #ifndef _OUSIA_RESOURCE_HPP_
 #define _OUSIA_RESOURCE_HPP_
 
+#include <map>
+#include <memory>
+#include <string>
+
 namespace ousia {
 
+// Forward declaration
+class ResourceLocator;
+
+/**
+ * This enum contains all possible types of includable resources in Ousía.
+ */
+enum class ResourceType {
+	/**
+     * Unknown type.
+     */
+	UNKNOWN,
+
+	/**
+     * The resource contains a domain description.
+     */
+	DOMAIN_DESC,
+
+	/**
+     * The resource contains a typesystem description.
+     */
+	TYPESYSTEM,
+
+	/**
+     * The resource contains a simple document.
+     */
+	DOCUMENT,
 
+	/**
+     * The resource contains style attributes.
+     */
+	ATTRIBUTES,
+
+	/**
+     * The resource is a stylesheet.
+     */
+	STYLESHEET,
+
+	/**
+     * The resource contains script (note that the actual scripting language is
+     * not specified by the resource type).
+     */
+	SCRIPT,
+
+	/**
+     * Generic data, such as e.g. images.
+     */
+	DATA
+};
+
+/**
+ * A Location contains the location of a Resource, e.g. a file path
+ * on a hard drive. Note that the 'found' flag might be set to false
+ * indicating that a resource was not found.
+ */
+class Resource {
+private:
+	/**
+	 * Specifies whether the resource points at a valid location or not.
+	 */
+	bool valid;
 
+	/**
+	 * Reference pointing at the location
+	 */
+	ResourceLocator const *locator;
+
+	/**
+	 * Requested type of the resource.
+	 */
+	ResourceType type;
+
+	/**
+	 * This is a fully qualified/canonical path to the resource found or
+	 * in an undefined state (possibly empty) if the 'valid' flag is set
+	 * to 'false'.
+	 */
+	std::string location;
+
+public:
+	/**
+	 * Default constructor of the Resource class, represents an invalid
+	 * resource.
+	 */
+	Resource();
+
+	/**
+	 * Constructor of the Resource class.
+	 *
+	 * @param valid specifies whether the Resource is valid or not.
+	 * @param locator specifies the resource locator that was used to locate the
+	 * resource.
+	 */
+	Resource(bool valid, const ResourceLocator &locator,
+	         ResourceType type, const std::string &location);
+
+	/**
+	 * This calls the 'stream' method of the underlying ResourceLocator that
+	 * found this location and returns a stream containing the data of the
+	 * Resource at this location.
+	 *
+	 * @return a stream containing the data of the Resource at this
+	 *         location. This has to be a unique_pointer because the current
+	 *         C++11 compiler does not yet support move semantics for
+	 *         streams.
+	 */
+	std::unique_ptr<std::istream> stream() const;
+
+	/**
+	 * Returns whether this resource is valid or not.
+	 *
+	 * @return true if the resource is valid, false otherwise.
+	 */
+	bool isValid() const { return valid; }
+
+	/**
+	 * Returns a reference pointing at the locator that was used to locate this
+	 * resource.
+	 *
+	 * @return the locator used for locating this resource.
+	 */
+	const ResourceLocator &getLocator() const { return *locator; }
+
+	/**
+	 * Returns the type of the resource that was requested when the resource was
+	 * located.
+	 *
+	 * @return the type of the resource.
+	 */
+	ResourceType getType() const { return type; }
+
+	/**
+	 * Returns a canonical location that can be used in a hash map to identify
+	 * a resource.
+	 */
+	const std::string &getLocation() const { return location; }
+};
+
+/**
+ * Invalid resource instance.
+ */
+extern const Resource NullResource;
 }
 
 #endif /* _OUSIA_RESOURCE_HPP_ */
diff --git a/src/core/resource/ResourceLocator.cpp b/src/core/resource/ResourceLocator.cpp
index e69de29..1b8490d 100644
--- a/src/core/resource/ResourceLocator.cpp
+++ b/src/core/resource/ResourceLocator.cpp
@@ -0,0 +1,103 @@
+/*
+    Ousía
+    Copyright (C) 2014, 2015  Benjamin Paaßen, Andreas Stöckel
+
+    This program is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#include <sstream>
+
+#include "Resource.hpp"
+#include "ResourceLocator.hpp"
+
+namespace ousia {
+
+/* Class ResourceLocator */
+
+bool ResourceLocator::locate(Resource &resource, const std::string &path,
+                             const ResourceType type,
+                             const Resource &relativeTo) const
+{
+	if (&relativeTo.getLocator() == this) {
+		return doLocate(resource, path, type, relativeTo.getLocation());
+	}
+	return doLocate(resource, path, type, "");
+}
+
+bool ResourceLocator::locate(Resource &resource, const std::string &path,
+                             const ResourceType type,
+                             const std::string &relativeTo) const
+{
+	return doLocate(resource, path, type, relativeTo);
+}
+
+std::unique_ptr<std::istream> ResourceLocator::stream(
+    const std::string &location) const
+{
+	return doStream(location);
+}
+
+/* Class StaticResourceLocator */
+
+bool StaticResourceLocator::doLocate(
+    Resource &resource, const std::string &path, const ResourceType type,
+    const std::string &relativeTo) const
+{
+	auto it = resources.find(path);
+	if (it != resources.end()) {
+		resource = Resource(true, *this, type, path);
+		return true;
+	}
+	return false;
+}
+
+std::unique_ptr<std::istream> StaticResourceLocator::doStream(
+    const std::string &location) const
+{
+	auto it = resources.find(location);
+	if (it != resources.end()) {
+		return std::unique_ptr<std::istream>{new std::stringstream{it->second}};
+	}
+	return std::unique_ptr<std::istream>{new std::stringstream{""}};
+}
+
+void StaticResourceLocator::store(const std::string &path,
+                                  const std::string &data)
+{
+	auto it = resources.find(path);
+	if (it != resources.end()) {
+		it->second = data;
+	} else {
+		resources.emplace(path, data);
+	}
+}
+
+/* Class NullResourceLocatorImpl */
+
+bool NullResourceLocatorImpl::doLocate(Resource &resource,
+                                       const std::string &path,
+                                       const ResourceType type,
+                                       const std::string &relativeTo) const
+{
+	return false;
+}
+std::unique_ptr<std::istream> NullResourceLocatorImpl::doStream(
+    const std::string &location) const
+{
+	return std::unique_ptr<std::istream>{new std::stringstream{""}};
+}
+
+const NullResourceLocatorImpl NullResourceLocator;
+}
+
diff --git a/src/core/resource/ResourceLocator.hpp b/src/core/resource/ResourceLocator.hpp
index 39c7b30..c1d0807 100644
--- a/src/core/resource/ResourceLocator.hpp
+++ b/src/core/resource/ResourceLocator.hpp
@@ -22,8 +22,13 @@
 #include <istream>
 #include <memory>
 
+#include "Resource.hpp"
+
 namespace ousia {
 
+// Forward declaration
+class ResourceLocator;
+
 /**
  * A ResourceLocator is a class able to locate resources in some way, usually
  * on the hard drive.
@@ -33,84 +38,82 @@ namespace ousia {
  * locations (e.g. online resources, .zip files, etc.).
  */
 class ResourceLocator {
-public:
+protected:
 	/**
-	 * This enum contains all possible types of includable resources in Ousía.
+	 * The locate function uses this ResourceLocator to search for a given
+	 * Resource name (path parameter). It returns a Location with the
+	 * 'valid' flag set accordingly.
+	 *
+	 * @param resource reference to a Resource the will be set the the found
+	 * location. The content of the variable will be only valid if the return
+	 * value of this function is set to true.
+	 * @param path is the resource name.
+	 * @param relativeTo is an already resolved fully qualified name/canonical
+	 * path that is to be used as base directory for this search. It is
+	 * guaranteed that the path was produced by this locator instance. Otherwise
+	 * this argument is set to an empty string.
+	 * @param type is the type of this resource.
+	 * @return true if a resource could be found, false otherwise.
+	 */
+	virtual bool doLocate(Resource &resource, const std::string &path,
+	                      const ResourceType type,
+	                      const std::string &relativeTo) const = 0;
+
+	/**
+	 * This method returns a stream containing the data of the resource at the
+	 * given location.
+	 *
+	 * @param location is a found location, most likely from a Location.
+	 *
+	 * @return a stream containing the data of the Resource at this
+	 *         location. This has to be a unique_pointer because the current
+	 *         C++11 compiler does not yet support move semantics for
+	 *         streams.
 	 */
-	enum class Type {
-		// A Domain description
-		DOMAIN_DESC,
-		// An ECMA/JavaScript
-		SCRIPT,
-		// A Type System
-		TYPESYS,
-		DOCUMENT,
-		ATTRIBUTES,
-		// TODO: Aren't documents and attribute descriptors missing?
-		// TODO: What is the purpose of these two?
-		GENERIC_MODULE,
-		GENERIC_INCLUDE
-	};
+	virtual std::unique_ptr<std::istream> doStream(
+	    const std::string &location) const = 0;
 
+public:
 	/**
-	 * A Location contains the location of a Resource, e.g. a file path
-	 * on a hard drive. Note that the 'found' flag might be set to false
-	 * indicating that a resource was not found.
+	 * Virtual destructor of the ResourceLocator interface.
 	 */
-	struct Location {
-		const bool found;
-		const ResourceLocator &locator;
-		const Type type;
-		/**
-		 * This is a fully qualified/canonical path to the resource found or
-		 * in an undefined state (possibly empty) if the 'found' flag is set
-		 * to 'false'.
-		 */
-		const std::string location;
-
-		Location(const bool found, const ResourceLocator &locator,
-		         const Type type, const std::string location)
-		    : found(found), locator(locator), type(type), location(location)
-		{
-		}
-
-		/**
-		 * This calls the 'stream' method of the underlying ResourceLocator that
-		 * found this location and returns a stream containing the data of the
-		 * Resource at this location.
-		 *
-		 * @return a stream containing the data of the Resource at this
-		 *         location. This has to be a unique_pointer because the current
-		 *         C++11 compiler does not yet support move semantics for
-		 *         streams.
-		 */
-		std::unique_ptr<std::istream> stream() const
-		{
-			return std::move(locator.stream(location));
-		}
-	};
+	virtual ~ResourceLocator() {}
 
 	/**
 	 * The locate function uses this ResourceLocator to search for a given
-	 * Resource name (path parameter). It returns a Location with the
-	 * 'found' flag set accordingly.
+	 * Resource name (path parameter).
 	 *
+	 * @param resource reference to a Resource the will be set the the found
+	 * location. The content of the variable will be only valid if the return
+	 * value of this function is set to true.
 	 * @param path is the resource name.
-	 * @param relativeTo is an already resolved fully qualified name/canonical
-	 *                   path that is to be used as base directory for this
-	 *                   search.
+	 * @param relativeTo is an already resolved Resource.
 	 * @param type is the type of this resource.
+	 * @return true if a resource could be found, false otherwise.
+	 */
+	bool locate(Resource &resource, const std::string &path,
+	            const ResourceType type = ResourceType::UNKNOWN,
+	            const Resource &relativeTo = NullResource) const;
+
+	/**
+	 * The locate function uses this ResourceLocator to search for a given
+	 * Resource name (path parameter).
 	 *
-	 * @return A Location containing either the found location of the
-	 *         Resource and the found flag set to 'true' or an empty location
-	 *         and the found flag set to 'false'.
+	 * @param resource reference to a Resource the will be set the the found
+	 * location. The content of the variable will be only valid if the return
+	 * value of this function is set to true.
+	 * @param path is the resource name.
+	 * @param type is the type of this resource.
+	 * @param relativeTo is the location of an already resolved resource
+	 * relative to which this resource should be located.
+	 * @return true if a resource could be found, false otherwise.
 	 */
-	virtual Location locate(const std::string &path,
-	                        const std::string &relativeTo,
-	                        const Type type) const = 0;
+	bool locate(Resource &resource, const std::string &path,
+	            const ResourceType type,
+	            const std::string &relativeTo) const;
 
 	/**
-	 * This method returns a strem containing the data of the resource at the
+	 * This method returns a stream containing the data of the resource at the
 	 * given location.
 	 *
 	 * @param location is a found location, most likely from a Location.
@@ -120,9 +123,70 @@ public:
 	 *         C++11 compiler does not yet support move semantics for
 	 *         streams.
 	 */
-	virtual std::unique_ptr<std::istream> stream(
-	    const std::string &location) const = 0;
+	std::unique_ptr<std::istream> stream(const std::string &location) const;	
+};
+
+/**
+ * The StaticResourceLocator class stores a set of predefined resources in
+ * memory and allows to return these.
+ */
+class StaticResourceLocator : public ResourceLocator {
+private:
+	/**
+	 * Map containing the paths and the corresponding stored data.
+	 */
+	std::map<std::string, std::string> resources;
+
+protected:
+	/**
+	 * Always returns false.
+	 */
+	bool doLocate(Resource &resource, const std::string &path,
+	              const ResourceType type,
+	              const std::string &relativeTo) const override;
+
+	/**
+	 * Returns an input stream containing an empty string.
+	 */
+	std::unique_ptr<std::istream> doStream(
+	    const std::string &location) const override;
+
+public:
+	/**
+	 * Stores static (string) data for the given path.
+	 *
+	 * @param path is the path the resource should be stored with.
+	 * @param data is the data that should be stored for that path.
+	 */
+	void store(const std::string &path, const std::string &data);
 };
+
+/**
+ * Implementation of the NullResourceLocator - contains a default implementation
+ * of the ResourceLocator class that does nothing. This class is e.g. used in
+ * the default constructor of the resource class. A instance of the class is
+ * provided as "NullResourceLocator".
+ */
+class NullResourceLocatorImpl : public ResourceLocator {
+protected:
+	/**
+	 * Always returns false.
+	 */
+	bool doLocate(Resource &resource, const std::string &path,
+	              const ResourceType type,
+	              const std::string &relativeTo) const override;
+
+	/**
+	 * Returns an input stream containing an empty string.
+	 */
+	std::unique_ptr<std::istream> doStream(
+	    const std::string &location) const override;
+};
+
+/**
+ * The NullResourceLocator is used as a fallback for invalid Resources.
+ */
+extern const NullResourceLocatorImpl NullResourceLocator;
 }
 
 #endif /* _RESOURCE_LOCATOR_HPP_ */