Add header for openPMD-specific errors

CMakeLists.txt

@@ -371,6 +371,7 @@ set(CORE_SOURCE
         src/ChunkInfo.cpp
         src/Dataset.cpp
         src/Datatype.cpp
+        src/Error.cpp
         src/Format.cpp
         src/Iteration.cpp
         src/IterationEncoding.cpp
@@ -410,10 +411,12 @@ set(IO_SOURCE
         src/IO/ADIOS/ADIOS2PreloadAttributes.cpp
         src/IO/InvalidatableFile.cpp)
 set(IO_ADIOS1_SEQUENTIAL_SOURCE
+        src/Error.cpp
         src/auxiliary/Filesystem.cpp
         src/ChunkInfo.cpp
         src/IO/ADIOS/ADIOS1IOHandler.cpp)
 set(IO_ADIOS1_SOURCE
+        src/Error.cpp
         src/auxiliary/Filesystem.cpp
         src/ChunkInfo.cpp
         src/IO/ADIOS/ParallelADIOS1IOHandler.cpp)
@@ -627,6 +630,7 @@ if(openPMD_HAVE_PYTHON)
         src/binding/python/Container.cpp
         src/binding/python/Dataset.cpp
         src/binding/python/Datatype.cpp
+        src/binding/python/Error.cpp
         src/binding/python/Helper.cpp
         src/binding/python/Iteration.cpp
         src/binding/python/IterationEncoding.cpp

include/openPMD/Error.hpp

@@ -0,0 +1,54 @@
+#pragma once
+
+#include <exception>
+#include <string>
+#include <utility>
+
+namespace openPMD
+{
+/**
+ * @brief Base class for all openPMD-specific error types.
+ *
+ * Should not be instantiated directly, but only by implementing child classes
+ * in the openPMD::error namespace.
+ *
+ */
+class Error : public std::exception
+{
+private:
+    std::string m_what;
+
+protected:
+    Error( std::string what ) : m_what( what )
+    {
+    }
+
+public:
+    virtual const char * what() const noexcept;
+
+    Error( Error const & ) = default;
+    Error( Error && ) = default;
+
+    Error & operator=( Error const & ) = default;
+    Error & operator=( Error && ) = default;
+
+    virtual ~Error() noexcept = default;
+};
+
+namespace error
+{
+    /**
+     * @brief An operation was requested that is not supported in a specific
+     *     backend.
+     *
+     * Example: Append mode is not available in ADIOS1.
+     */
+    class OperationUnsupportedInBackend : public Error
+    {
+    public:
+        std::string backend;
+        OperationUnsupportedInBackend(
+            std::string backend_in, std::string what );
+    };
+}
+}

include/openPMD/openPMD.hpp

@@ -27,6 +27,7 @@ namespace openPMD {}
 // IWYU pragma: begin_exports
 #include "openPMD/Dataset.hpp"
 #include "openPMD/Datatype.hpp"
+#include "openPMD/Error.hpp"
 #include "openPMD/IterationEncoding.hpp"
 #include "openPMD/Iteration.hpp"
 #include "openPMD/Mesh.hpp"

src/Error.cpp

@@ -0,0 +1,19 @@
+#include "openPMD/Error.hpp"
+
+namespace openPMD
+{
+const char * Error::what() const noexcept
+{
+    return m_what.c_str();
+}
+
+namespace error
+{
+    OperationUnsupportedInBackend::OperationUnsupportedInBackend(
+        std::string backend_in, std::string what )
+        : Error( "Operation unsupported in " + backend_in + ": " + what )
+        , backend{ std::move( backend_in ) }
+    {
+    }
+}
+}

src/binding/python/Error.cpp

@@ -0,0 +1,19 @@
+#include "openPMD/Error.hpp"
+
+#include <pybind11/pybind11.h>
+
+namespace py = pybind11;
+using namespace openPMD;
+
+void init_Error( py::module & m )
+{
+    auto & baseError = py::register_exception< Error >( m, "Error" );
+    py::register_exception< error::OperationUnsupportedInBackend >(
+        m, "ErrorOperationUnsupportedInBackend", baseError );
+
+#ifndef NDEBUG
+    m.def( "test_throw", []( std::string description ) {
+        throw error::OperationUnsupportedInBackend( "json", description );
+    } );
+#endif
+}

src/binding/python/openPMD.cpp

@@ -40,6 +40,7 @@ void init_Chunk(py::module &m);
 void init_Container(py::module &);
 void init_Dataset(py::module &);
 void init_Datatype(py::module &);
+void init_Error(py::module &);
 void init_Helper(py::module &);
 void init_Iteration(py::module &);
 void init_IterationEncoding(py::module &);
@@ -90,6 +91,7 @@ PYBIND11_MODULE(openpmd_api_cxx, m) {
     init_Attributable(m);
     init_Chunk(m);
     init_Container(m);
+    init_Error(m);
     init_BaseRecord(m);
     init_Dataset(m);
     init_Datatype(m);

test/python/unittest/API/APITest.py

@@ -1997,6 +1997,13 @@ def testJsonConfigADIOS2(self):
             self.assertEqual(chunk_x[i], i)
             self.assertEqual(chunk_y[i], i)
 
+    def testError(self):
+        if 'test_throw' in io.__dict__:
+            with self.assertRaises(io.ErrorOperationUnsupportedInBackend):
+                io.test_throw("test description")
+            with self.assertRaises(io.Error):
+                io.test_throw("test description")
+
     def testCustomGeometries(self):
         DS = io.Dataset
         DT = io.Datatype