Outline exceptionStr function bodies

Summary: [Folly] Outline `exceptionStr` function bodies and move them to the `.cpp`.

Reviewed By: ot, luciang

Differential Revision: D22529702

fbshipit-source-id: 165c14009f224e86e63b3a3126c8b837cf3793f5

folly/ExceptionString.cpp

+/*
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * 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.
+ */
+
+#include <folly/ExceptionString.h>
+
+namespace folly {
+
+/**
+ * Debug string for an exception: include type and what(), if
+ * defined.
+ */
+fbstring exceptionStr(const std::exception& e) {
+#if FOLLY_HAS_RTTI
+  fbstring rv(demangle(typeid(e)));
+  rv += ": ";
+#else
+  fbstring rv("Exception (no RTTI available): ");
+#endif
+  rv += e.what();
+  return rv;
+}
+
+fbstring exceptionStr(std::exception_ptr ep) {
+  if (!kHasExceptions) {
+    return "Exception (catch unavailable)";
+  }
+  return catch_exception(
+      [&]() -> fbstring {
+        return catch_exception<std::exception const&>(
+            [&]() -> fbstring { std::rethrow_exception(ep); },
+            [](auto&& e) { return exceptionStr(e); });
+      },
+      []() -> fbstring { return "<unknown exception>"; });
+}
+
+} // namespace folly

folly/ExceptionString.h

@@ -30,29 +30,9 @@ namespace folly {
  * Debug string for an exception: include type and what(), if
  * defined.
  */
-inline fbstring exceptionStr(const std::exception& e) {
-#if FOLLY_HAS_RTTI
-  fbstring rv(demangle(typeid(e)));
-  rv += ": ";
-#else
-  fbstring rv("Exception (no RTTI available): ");
-#endif
-  rv += e.what();
-  return rv;
-}
+fbstring exceptionStr(const std::exception& e);
 
-inline fbstring exceptionStr(std::exception_ptr ep) {
-  if (!kHasExceptions) {
-    return "Exception (catch unavailable)";
-  }
-  return catch_exception(
-      [&]() -> fbstring {
-        return catch_exception<std::exception const&>(
-            [&]() -> fbstring { std::rethrow_exception(ep); },
-            [](auto&& e) { return exceptionStr(e); });
-      },
-      []() -> fbstring { return "<unknown exception>"; });
-}
+fbstring exceptionStr(std::exception_ptr ep);
 
 template <typename E>
 auto exceptionStr(const E& e) -> typename std::