Add K4_GAUDI_CHECK macro.

k4FWCore/include/k4FWCore/k4_check.h

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+/*
+ * Copyright (c) 2014-2024 Key4hep-Project.
+ *
+ * This file is part of Key4hep.
+ * See https://key4hep.github.io/key4hep-doc/ for further info.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+/**
+ * @file k4FWCore/k4FWCore/include/k4FWCore/check.h
+ * @author scott snyder <[email protected]>
+ * @date Apr, 2025
+ * @brief Helper to check return codes in a Gaudi component.
+ */
+
+#ifndef K4FWCORE_K4_CHECK_H
+#define K4FWCORE_K4_CHECK_H
+
+#include "GaudiKernel/StatusCode.h"
+
+/**
+ * @brief Helper to check return codes in a Gaudi component.
+ *
+ * <code>K4_GAUDI_CHECK( EXP )</code> will evaluate @c EXP.  If this results
+ * in something that evaluates to @c false (including @c StatusCode::FAILURE),
+ * we emit an error message and immediately return a @c StatusCode::FAILURE.
+ * This can be used to make checking the results of calls from Gaudi components
+ * easier to read.  For example, a typical call to something that returns
+ * a @c StatusCode might be implemented something like this:
+ *
+ *@code
+ *  StatusCode sc = something();
+ *  if (! sc.isSuccess() ) {
+ *    error() << "Something went wrong." << endmsg;
+ *    return sc;
+ *  }
+ @endcode
+ *
+ * This has several undesirable properties.  First, it is overly verbose.
+ * 80% of the code in this example is devoted to error handling; if there
+ * are many of these, it becomes difficult to read what the code is
+ * actually doing.
+ *
+ * Second, there is no standardization of the error messages produced,
+ * and they are sometimes difficult to trace back to the actual offending
+ * source code.
+ *
+ * Third, code like this typically gets written by cut-and-paste,
+ * which is notoriously error-prone.
+ *
+ * The helper here can address these issues; rather than the code above, use
+ *
+ *@code
+ *  K4_GAUDI_CHECK( something() );
+ @endcode
+ *
+ * The error message produced by this will contain the text of the
+ * expression that failed, as well as the corresponding source file and line.
+ * Note that macro has to be used in a context such as a Gaudi component
+ * where the @c error() function is defined to return a Gaudi @c MsgStream.
+ */
+#define K4_GAUDI_CHECK(EXP)                                                                                            \
+  do {                                                                                                                 \
+    if (!(EXP)) {                                                                                                      \
+      error() << __FILE__ << ":" << __LINE__ << " error returned from: " << #EXP << endmsg;                            \
+      return StatusCode::FAILURE;                                                                                      \
+    }                                                                                                                  \
+  } while (0)
+
+#endif // not K4FWCORE_K4_CHECK_H