Provide an API for accessing internal errors.

code/Common/BaseImporter.cpp

@@ -130,11 +130,17 @@ aiScene *BaseImporter::ReadFile(Importer *pImp, const std::string &pFile, IOSyst
         // passes scale into ScaleProcess
         UpdateImporterScale(pImp);
 
-    } catch (const std::exception &err) {
+    } catch( const DeadlyImportError& err )    {
         // extract error description
         m_ErrorText = err.what();
         ASSIMP_LOG_ERROR(m_ErrorText);
         return nullptr;
+    } catch( const std::exception& err )    {
+        // extract error description
+        m_ErrorText = "Internal error";
+        ASSIMP_LOG_ERROR(err.what());
+        m_internalException = std::current_exception();
+        return nullptr;
     }
 
     // return what we gathered from the import.

code/Common/Importer.cpp

@@ -387,6 +387,7 @@ void Importer::FreeScene( ) {
     pimpl->mScene = nullptr;
 
     pimpl->mErrorString = "";
+    pimpl->mInternalException = std::exception_ptr();
     ASSIMP_END_EXCEPTION_REGION(void);
 }
 
@@ -399,6 +400,13 @@ const char* Importer::GetErrorString() const {
     return pimpl->mErrorString.c_str();
 }
 
+const std::exception_ptr& Importer::GetInternalException() const {
+    ai_assert(nullptr != pimpl);
+    
+    // Must remain valid as long as ReadFile() or FreeFile() are not called
+    return pimpl->mInternalException;
+}
+
 // ------------------------------------------------------------------------------------------------
 // Enable extra-verbose mode
 void Importer::SetExtraVerbose(bool bDo) {
@@ -426,6 +434,7 @@ aiScene* Importer::GetOrphanedScene() {
     pimpl->mScene = nullptr;
 
     pimpl->mErrorString = ""; // reset error string
+    pimpl->mInternalException = std::exception_ptr();
     ASSIMP_END_EXCEPTION_REGION(aiScene*);
     
     return s;
@@ -502,7 +511,7 @@ const aiScene* Importer::ReadFileFromMemory( const void* pBuffer,
     ReadFile(fbuff,pFlags);
     SetIOHandler(io);
 
-    ASSIMP_END_EXCEPTION_REGION_WITH_ERROR_STRING(const aiScene*, pimpl->mErrorString);
+    ASSIMP_END_EXCEPTION_REGION_WITH_ERROR_STRING(const aiScene*, pimpl->mErrorString, pimpl->mInternalException);
     return pimpl->mScene;
 }
 
@@ -709,6 +718,7 @@ const aiScene* Importer::ReadFile( const char* _pFile, unsigned int pFlags) {
         // if failed, extract the error string
         else if( !pimpl->mScene) {
             pimpl->mErrorString = imp->GetErrorText();
+            pimpl->mInternalException = imp->GetInternalException();
         }
 
         // clear any data allocated by post-process steps
@@ -733,7 +743,7 @@ const aiScene* Importer::ReadFile( const char* _pFile, unsigned int pFlags) {
 #endif // ! ASSIMP_CATCH_GLOBAL_EXCEPTIONS
 
     // either successful or failure - the pointer expresses it anyways
-    ASSIMP_END_EXCEPTION_REGION_WITH_ERROR_STRING(const aiScene*, pimpl->mErrorString);
+    ASSIMP_END_EXCEPTION_REGION_WITH_ERROR_STRING(const aiScene*, pimpl->mErrorString, pimpl->mInternalException);
     
     return pimpl->mScene;
 }

code/Common/Importer.h

@@ -97,9 +97,14 @@ public:
     /** The imported data, if ReadFile() was successful, nullptr otherwise. */
     aiScene* mScene;
 
-    /** The error description, if there was one. */
+    /** The error description, if there was one. In the case of a
+     *  failure not caused by a DeadlyImportError, mInternalException will
+     *  carry the exception and this will be just "Internal error". */
     std::string mErrorString;
 
+    /** Any exception which wasn't a DeadlyImportError */
+    std::exception_ptr mInternalException;
+
     /** List of integer properties */
     IntPropertyMap mIntProperties;
 
@@ -133,6 +138,7 @@ ImporterPimpl::ImporterPimpl() AI_NO_EXCEPT
 , mPostProcessingSteps()
 , mScene( nullptr )
 , mErrorString()
+, mInternalException()
 , mIntProperties()
 , mFloatProperties()
 , mStringProperties()

include/assimp/BaseImporter.h

@@ -150,6 +150,15 @@ public:
         return m_ErrorText;
     }
 
+    // -------------------------------------------------------------------
+    /** Returns the exception of the last non-DeadlyImportError that occurred.
+     * @return A description of the last error that occurred. An empty
+     * string if there was no error.
+     */
+    const std::exception_ptr& GetInternalException() const {
+        return m_internalException;
+    }
+
     // -------------------------------------------------------------------
     /** Called prior to ReadFile().
      * The function is a request to the importer to update its configuration
@@ -411,8 +420,11 @@ private:
     virtual void UpdateImporterScale(Importer *pImp);
 
 protected:
-    /// Error description in case there was one.
+    /// Error description when a DeadlyImportError occurred during import.
+    /// In case of other errors, this will just be "Internal error"
     std::string m_ErrorText;
+    /// Any exception which wasn't due to the asset being incorrect.
+    std::exception_ptr m_internalException;
     /// Currently set progress handler.
     ProgressHandler *m_progress;
 };

include/assimp/Exceptional.h

@@ -123,14 +123,15 @@ struct ExceptionSwallower<void> {
     {                                   \
         try {
 
-#define ASSIMP_END_EXCEPTION_REGION_WITH_ERROR_STRING(type, ASSIMP_END_EXCEPTION_REGION_errorString) \
+#define ASSIMP_END_EXCEPTION_REGION_WITH_ERROR_STRING(type, ASSIMP_END_EXCEPTION_REGION_errorString, ASSIMP_END_EXCEPTION_REGION_internalError) \
     }                                                                                                                                           \
     catch (const DeadlyImportError &e) {                                                                                                        \
         ASSIMP_END_EXCEPTION_REGION_errorString = e.what();                                                                                     \
         return ExceptionSwallower<type>()();                                                                                                    \
     }                                                                                                                                           \
     catch (...) {                                                                                                                               \
-        ASSIMP_END_EXCEPTION_REGION_errorString = "Unknown exception";                               \
+        ASSIMP_END_EXCEPTION_REGION_errorString = "Internal error";                                                                             \
+        ASSIMP_END_EXCEPTION_REGION_internalError = std::current_exception();                                                                   \
         return ExceptionSwallower<type>()();                                                                                                    \
     }                                                                                                                                           \
 }

include/assimp/Importer.hpp

@@ -495,6 +495,17 @@ public:
      * following methods is called: #ReadFile(), #FreeScene(). */
     const char *GetErrorString() const;
 
+    // -------------------------------------------------------------------
+    /** Returns Returns an internal exception if one occurred during import.
+     *
+     * Returns the last non-DeadlyImportError exception which occurred.
+     * @return The last exception which occurred which wasn't a
+     *   DeadlyImportError.
+     *
+     * @note The returned value remains valid until one of the
+     * following methods is called: #ReadFile(), #FreeScene(). */
+    const std::exception_ptr& GetInternalException() const;
+
     // -------------------------------------------------------------------
     /** Returns the scene loaded by the last successful call to ReadFile()
      *