treewide: use C++ exceptions properly

Since the codebase is designed around proper C++ idioms such as RAII, it
makes sense to only use C++ exceptions internally instead of mixing
exceptions and error codes. The exceptions are now caught at top level
to preserve compatibility with the existing error code-based API.

Note that we deliberately do not catch C++ runtime errors (such as
`std::bad_alloc`) nor logic errors (aka failed assertions) because no
actual handling can ever happen for such errors.

However, in the C interface we do catch _all_ exceptions (...) and
convert them into a wild-card error code.

1 files changed, 87 insertions, 0 deletions

diff --git a/src/cxpp11_common.hpp b/src/cxpp11_common.hpp
new file mode 100644
index 00000000..c164ec1d
--- /dev/null
+++ b/src/cxpp11_common.hpp
@@ -0,0 +1,87 @@
+#ifndef CLBLAST_CXPP11_COMMON_H_
+#define CLBLAST_CXPP11_COMMON_H_
+
+// C++
+#include <string>    // std::string
+#include <stdexcept> // std::runtime_error
+
+namespace clblast {
+// =================================================================================================
+
+// Basic exception class: represents an error happened inside our code
+// (as opposed to an error in C++ runtime)
+template <typename Base>
+class Error : public Base {
+ public:
+  using Base::Base;
+};
+
+// =================================================================================================
+
+// Represents a generic device-specific runtime error (returned by an OpenCL or CUDA API function)
+class DeviceError : public Error<std::runtime_error> {
+ public:
+  using Error<std::runtime_error>::Error;
+
+  static std::string TrimCallString(const char *where) {
+    const char *paren = strchr(where, '(');
+    if (paren) {
+      return std::string(where, paren);
+    } else {
+      return std::string(where);
+    }
+  }
+};
+
+// =================================================================================================
+
+// Represents a generic runtime error (aka environmental problem)
+class RuntimeError : public Error<std::runtime_error> {
+ public:
+  explicit RuntimeError(const std::string &reason):
+      Error("Run-time error: " + reason) {
+  }
+};
+
+// =================================================================================================
+
+// Represents a generic logic error (aka failed assertion)
+class LogicError : public Error<std::logic_error> {
+ public:
+  explicit LogicError(const std::string &reason):
+      Error("Internal logic error: " + reason) {
+  }
+};
+
+// =================================================================================================
+
+// Internal exception base class with a status field and a subclass-specific "details" field
+// which can be used to recreate an exception
+template <typename Base, typename Status>
+class ErrorCode : public Base {
+ public:
+  ErrorCode(Status status, const std::string &details, const std::string &reason):
+      Base(reason),
+      status_(status),
+      details_(details) {
+  }
+
+  Status status() const {
+    return status_;
+  }
+
+  const std::string& details() const {
+    return details_;
+  }
+
+ private:
+  const Status status_;
+  const std::string details_;
+};
+
+// =================================================================================================
+
+} // namespace clblast
+
+// CLBLAST_CXPP11_COMMON_H_
+#endif