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/*
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/>.
*/
#ifndef _OUSIA_RESOURCE_LOCATOR_HPP_
#define _OUSIA_RESOURCE_LOCATOR_HPP_
#include <istream>
#include <memory>
namespace ousia {
/**
* A ResourceLocator is a class able to locate resources in some way, usually
* on the hard drive.
*
* We specify this as an abstract superclass to have an interface layer between
* the program core and possible future extensions in terms of resource
* locations (e.g. online resources, .zip files, etc.).
*/
class ResourceLocator {
public:
/**
* This enum contains all possible types of includable resources in Ousía.
*/
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
};
/**
* 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.
*/
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));
}
};
/**
* 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.
*
* @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 type is the type of this resource.
*
* @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'.
*/
virtual Location locate(const std::string &path,
const std::string &relativeTo,
const Type type) const = 0;
/**
* This method returns a strem 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.
*/
virtual std::unique_ptr<std::istream> stream(
const std::string &location) const = 0;
};
}
#endif /* _RESOURCE_LOCATOR_HPP_ */
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