Use appropriate preprocessor guards to allow building without exceptions

BUILD

@@ -38,6 +38,16 @@ config_setting(
     values = {"define": "grpc_no_ares=true"},
 )
 
+config_setting(
+    name = "grpc_allow_exceptions",
+    values = {"define": "GRPC_ALLOW_EXCEPTIONS=1"},
+)
+
+config_setting(
+    name = "grpc_disallow_exceptions",
+    values = {"define": "GRPC_ALLOW_EXCEPTIONS=0"},
+)
+
 config_setting(
     name = "remote_execution",
     values = {"define": "GRPC_PORT_ISOLATED_RUNTIME=1"},
@@ -544,24 +554,24 @@ grpc_cc_library(
 
 grpc_cc_library(
     name = "debug_location",
-    public_hdrs = ["src/core/lib/support/debug_location.h"],
     language = "c++",
+    public_hdrs = ["src/core/lib/support/debug_location.h"],
 )
 
 grpc_cc_library(
     name = "ref_counted",
-    public_hdrs = ["src/core/lib/support/ref_counted.h"],
     language = "c++",
+    public_hdrs = ["src/core/lib/support/ref_counted.h"],
     deps = [
-        "grpc_trace",
         "debug_location",
+        "grpc_trace",
     ],
 )
 
 grpc_cc_library(
     name = "ref_counted_ptr",
-    public_hdrs = ["src/core/lib/support/ref_counted_ptr.h"],
     language = "c++",
+    public_hdrs = ["src/core/lib/support/ref_counted_ptr.h"],
 )
 
 grpc_cc_library(

bazel/grpc_build_system.bzl

@@ -60,6 +60,10 @@ def grpc_cc_library(name, srcs = [], public_hdrs = [], hdrs = [],
     defines = select({"//:grpc_no_ares": ["GRPC_ARES=0"],
                       "//conditions:default": [],}) +
               select({"//:remote_execution":  ["GRPC_PORT_ISOLATED_RUNTIME=1"],
+                      "//conditions:default": [],} +
+              select({"//:grpc_allow_exceptions":  ["GRPC_ALLOW_EXCEPTIONS=1"],
+                      "//:grpc_disallow_exceptions":
+                      ["GRPC_ALLOW_EXCEPTIONS=0"],
                       "//conditions:default": [],}),
     hdrs = _maybe_update_cc_library_hdrs(hdrs + public_hdrs),
     deps = deps + _get_external_deps(external_deps),

include/grpc++/impl/codegen/method_handler_impl.h

@@ -35,15 +35,19 @@ namespace internal {
 // so this process doesn't require additional overhead in the common case.
 // Additionally, we don't need to return if we caught an exception or not;
 // the handling is the same in either case.
-template <class F>
-Status CatchingFunctionHandler(F&& callable) {
+template <class Callable>
+Status CatchingFunctionHandler(Callable&& handler) {
+#if GRPC_ALLOW_EXCEPTIONS
   try {
-    return callable();
+    return handler();
   } catch (const std::exception& e) {
     return Status(StatusCode::UNKNOWN, e.what());
   } catch (...) {
     return Status(StatusCode::UNKNOWN, "Exception in method handler");
   }
+#else
+  return handler();
+#endif
 }
 
 /// A wrapper class of an application provided rpc method handler.

include/grpc/impl/codegen/port_platform.h

@@ -477,6 +477,21 @@ typedef unsigned __int64 uint64_t;
 #endif /* GPR_ATTRIBUTE_NO_TSAN (2) */
 #endif /* GPR_ATTRIBUTE_NO_TSAN (1) */
 
+/* GRPC_ALLOW_EXCEPTIONS should be 0 or 1 if exceptions are allowed or not */
+#ifndef GRPC_ALLOW_EXCEPTIONS
+/* If not already set, set to 1 on Windows (style guide standard) but to
+ * 0 on non-Windows platforms unless the compiler defines __EXCEPTIONS */
+#ifdef GPR_WINDOWS
+#define GRPC_ALLOW_EXCEPTIONS 1
+#else
+#ifdef __EXCEPTIONS
+#define GRPC_ALLOW_EXCEPTIONS 1
+#else
+#define GRPC_ALLOW_EXCEPTIONS 0
+#endif
+#endif
+#endif
+
 #ifndef __STDC_FORMAT_MACROS
 #define __STDC_FORMAT_MACROS
 #endif

test/cpp/end2end/exception_test.cc

@@ -24,6 +24,7 @@
 #include <grpc++/server.h>
 #include <grpc++/server_builder.h>
 #include <grpc++/server_context.h>
+#include <grpc/impl/codegen/port_platform.h>
 
 #include "src/proto/grpc/testing/echo.grpc.pb.h"
 #include "test/core/util/test_config.h"
@@ -35,6 +36,7 @@ namespace testing {
 
 const char* kErrorMessage = "This service caused an exception";
 
+#if GRPC_ALLOW_EXCEPTIONS
 class ExceptingServiceImpl : public ::grpc::testing::EchoTestService::Service {
  public:
   Status Echo(ServerContext* server_context, const EchoRequest* request,
@@ -106,6 +108,8 @@ TEST_F(ExceptionTest, RequestStream) {
   EXPECT_EQ(s.error_message(), kErrorMessage);
 }
 
+#endif
+
 }  // namespace testing
 }  // namespace grpc