diff options
Diffstat (limited to 'src/core/resource/ResourceLocator.hpp')
| -rw-r--r-- | src/core/resource/ResourceLocator.hpp | 194 |
1 files changed, 129 insertions, 65 deletions
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_ */ |