assimp/code/BaseImporter.h

105 lines
3.9 KiB
C++

/** @file Definition of the base class for all importer worker classes. */
#ifndef AI_BASEIMPORTER_H_INC
#define AI_BASEIMPORTER_H_INC
#include <string>
struct aiScene;
namespace Assimp
{
class IOSystem;
// ---------------------------------------------------------------------------
/** Simple exception class to be thrown if an error occurs while importing. */
class ImportErrorException
{
public:
/** Constructor with arguments */
ImportErrorException( const std::string& pErrorText)
{
mErrorText = pErrorText;
}
/** Returns the error text provided when throwing the exception */
const std::string& GetErrorText() const { return mErrorText; }
private:
std::string mErrorText;
};
// ---------------------------------------------------------------------------
/** The BaseImporter defines a common interface for all importer worker
* classes.
*
* The interface defines two functions: CanRead() is used to check if the
* importer can handle the format of the given file. If an implementation of
* this function returns true, the importer then calls ReadFile() which
* imports the given file. ReadFile is not overridable, it just calls InternReadFile()
* and catches any ImportErrorException that might occur.
*/
class BaseImporter
{
friend class Importer;
protected:
/** Constructor to be privately used by Importer */
BaseImporter();
/** Destructor, private as well */
virtual ~BaseImporter();
public:
// -------------------------------------------------------------------
/** Returns whether the class can handle the format of the given file.
* @param pFile Path and file name of the file to be examined.
* @param pIOHandler The IO handler to use for accessing any file.
* @return true if the class can read this file, false if not.
*/
virtual bool CanRead( const std::string& pFile, IOSystem* pIOHandler) const = 0;
// -------------------------------------------------------------------
/** Imports the given file and returns the imported data.
* If the import succeeds, ownership of the data is transferred to the caller.
* If the import failes, NULL is returned. The function takes care that any
* partially constructed data is destroyed beforehand.
*
* @param pFile Path of the file to be imported.
* @param pIOHandler IO-Handler used to open this and possible other files.
* @return The imported data or NULL if failed. If it failed a human-readable
* error description can be retrieved by calling GetErrorText()
*
* @note This function is not intended to be overridden. Implement InternReadFile()
* to do the import. If an exception is thrown somewhere in InternReadFile(),
* this function will catch it and transform it into a suitable response to the caller.
*/
aiScene* ReadFile( const std::string& pFile, IOSystem* pIOHandler);
// -------------------------------------------------------------------
/** Returns the error description of the last error that occured.
* @return A description of the last error that occured. An empty string if no error.
*/
const std::string& GetErrorText() const { return mErrorText; }
protected:
// -------------------------------------------------------------------
/** Imports the given file into the given scene structure. The function is
* expected to throw an ImportErrorException if there is an error. If it
* terminates normally, the data in aiScene is expected to be correct.
* Override this function to implement the actual importing.
*
* @param pFile Path of the file to be imported.
* @param pScene The scene object to hold the imported data.
* @param pIOHandler The IO handler to use for any file access.
*/
virtual void InternReadFile( const std::string& pFile, aiScene* pScene, IOSystem* pIOHandler) = 0;
protected:
/** Error description in case there was one. */
std::string mErrorText;
};
} // end of namespace Assimp
#endif // AI_BASEIMPORTER_H_INC