gls_resource_file_mgr.h

#ifndef GLS_RESOURCE_FILE_MGR_H_INCLUDED
#define GLS_RESOURCE_FILE_MGR_H_INCLUDED

//////////////////// Provides support for creating DLLs ////////////////////////
#if (defined(GLSGEN_EXPORT_GLSGEOMETRYRESOURCE) || \
     defined(GLSGEN_IMPORT_GLSGEOMETRYRESOURCE) || \
     defined(GLS_EXPORT_GENERATED) || \
     defined(GLS_IMPORT_GENERATED)) \
     && defined(_MSC_VER) 
#  if defined(GLSGEN_EXPORT_GLSGEOMETRYRESOURCE) || defined(GLS_EXPORT_GENERATED)
#    define GLSGEN_GlsGeometryResource_EXPORT    __declspec(dllexport)
#  else
#    define GLSGEN_GlsGeometryResource_EXPORT    __declspec(dllimport)
#  endif
#else
#  define GLSGEN_GlsGeometryResource_EXPORT
#endif
///////////////////////////////////////////////////////////////////////////////

namespace disti {

/* class GlsResourceFileMgr
 *
 * This class manages all known resource files and provides an
 * API for objects to access the data for a named resource.
 *
 * This allows the runtime code to access required resources without
 * knowing their location.  Resources may be stored in individual files,
 * in an archive file, inline data in the source code, RCDATA, etc.
 *
 */
class GlsResourceFileMgr
{
protected:
    GlsResourceFileMgr();
    ~GlsResourceFileMgr();
public:

    /** Reference counted handle to binary resource data
     */
    class BinaryResource
    {
    protected:
        BinaryResource();
        virtual ~BinaryResource();
    public:
        /// Should be called to release this BinaryResource when it is longer needed
        virtual void Release() = 0;

        /// \returns the resource string name
        virtual const char* GetName() = 0;

        /// \returns size of the data in bytes
        virtual unsigned int GetDataSize() = 0;

        /// \returns raw pointer to the binary resource data (Read-only)
        virtual const char* GetDataPtr() = 0;
    };

    /** Lightweight reference to a resource
      */
    class ResourceRef
    {
    protected:
        // Need virtual destructor
        virtual ~ResourceRef() {}
    public:
        /// Increment the ResourceRef reference count
        virtual void AddRef() = 0;

        /// Should be called to release this ResourceRef when it is longer needed
        virtual void Release() = 0;

        /// \returns the resource string name
        virtual const char* GetName() = 0;

        // Obtain a pointer to the resource data
        // Make sure to Release() the BinaryResource when you are done with it (a SmartPtr can be used for this purpose)
        virtual BinaryResource* LoadBinaryData() = 0;
    };
    
    /* Used to hold a resource file open for loading time performance
     * \see CacheResourceFile
     */
    class ResourceCache
    {
    public:
        virtual ~ResourceCache() {}
        /// Increment the reference count
        virtual void AddRef() = 0;
        /// Decrement the reference count
        virtual void Release() = 0;
    };

    // Automatically release a resource
    // when no more AutoRelease instances reference it
    // \see CacheResourceFile
    template <class T>
    class AutoRelease
    {
    protected:
        T* _ptr;
    public:
        AutoRelease(T* obj) { _ptr = obj; }
        AutoRelease(const AutoRelease& other) { _ptr = other._ptr; if (_ptr) { _ptr->AddRef(); } }
        ~AutoRelease() { if (_ptr) { _ptr->Release(); } }
        T* get() { return _ptr; }
    };

    /**
      * \returns Reference to the GlsResourceFileMgr
      */
    GLSGEN_GlsGeometryResource_EXPORT static GlsResourceFileMgr& Instance();

    /** Get a reference to a given resource
      * \param resource_name The unique string name of the resource (relative path to the file if using resource folders)
      * \returns reference to the resource or NULL if the resource was not found.
      */
    GLSGEN_GlsGeometryResource_EXPORT ResourceRef* GetResourceRef(const char* resource_name);

    /** Tell the resource manager to load resources from the given location
      * This method may be called multiple times to specify multiple locations
      *
      * \param url path to the resources. e.g. "./resources/".  This may be a directory or zip file.
      * \param silent if false, then a popup is displayed to the user if the location is not found
      * \returns true if resources were successfully opened, false otherwise
      */
    GLSGEN_GlsGeometryResource_EXPORT bool AddResourceFolder(const char* url, bool silent=false);

    /** Loads resources for a given component into RAM.
      * The resources remain cached until the ResourceCache is Released.
      */
    GLSGEN_GlsGeometryResource_EXPORT AutoRelease<ResourceCache> CacheResourcesForComponent(const char* componentClassName);
};

} // end namespace disti

#endif