1 // 2 // Copyright 2016 gRPC authors. 3 // 4 // Licensed under the Apache License, Version 2.0 (the "License"); 5 // you may not use this file except in compliance with the License. 6 // You may obtain a copy of the License at 7 // 8 // http://www.apache.org/licenses/LICENSE-2.0 9 // 10 // Unless required by applicable law or agreed to in writing, software 11 // distributed under the License is distributed on an "AS IS" BASIS, 12 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 // See the License for the specific language governing permissions and 14 // limitations under the License. 15 // 16 17 #ifndef GRPC_CORE_EXT_FILTERS_CLIENT_CHANNEL_RESOLVER_FAKE_FAKE_RESOLVER_H 18 #define GRPC_CORE_EXT_FILTERS_CLIENT_CHANNEL_RESOLVER_FAKE_FAKE_RESOLVER_H 19 20 #include <grpc/support/port_platform.h> 21 22 #include "src/core/ext/filters/client_channel/resolver.h" 23 #include "src/core/lib/channel/channel_args.h" 24 #include "src/core/lib/gprpp/ref_counted.h" 25 #include "src/core/lib/iomgr/error.h" 26 27 #define GRPC_ARG_FAKE_RESOLVER_RESPONSE_GENERATOR \ 28 "grpc.fake_resolver.response_generator" 29 30 namespace grpc_core { 31 32 class FakeResolver; 33 34 /// A mechanism for generating responses for the fake resolver. 35 /// An instance of this class is passed to the fake resolver via a channel 36 /// argument (see \a MakeChannelArg()) and used to inject and trigger custom 37 /// resolutions. 38 // TODO(roth): I would ideally like this to be InternallyRefCounted 39 // instead of RefCounted, but external refs are currently needed to 40 // encode this in channel args. Once channel_args are converted to C++, 41 // see if we can find a way to fix this. 42 class FakeResolverResponseGenerator 43 : public RefCounted<FakeResolverResponseGenerator> { 44 public: FakeResolverResponseGenerator()45 FakeResolverResponseGenerator() {} 46 47 // Instructs the fake resolver associated with the response generator 48 // instance to trigger a new resolution with the specified result. If the 49 // resolver is not available yet, delays response setting until it is. This 50 // can be called at most once before the resolver is available. 51 void SetResponse(Resolver::Result result); 52 53 // Sets the re-resolution response, which is returned by the fake resolver 54 // when re-resolution is requested (via \a RequestReresolutionLocked()). 55 // The new re-resolution response replaces any previous re-resolution 56 // response that may have been set by a previous call. 57 void SetReresolutionResponse(Resolver::Result result); 58 59 // Unsets the re-resolution response. After this, the fake resolver will 60 // not return anything when \a RequestReresolutionLocked() is called. 61 void UnsetReresolutionResponse(); 62 63 // Tells the resolver to return a transient failure. 64 void SetFailure(); 65 66 // Same as SetFailure(), but instead of returning the error 67 // immediately, waits for the next call to RequestReresolutionLocked(). 68 void SetFailureOnReresolution(); 69 70 // Returns a channel arg containing \a generator. 71 static grpc_arg MakeChannelArg(FakeResolverResponseGenerator* generator); 72 73 // Returns the response generator in \a args, or null if not found. 74 static FakeResolverResponseGenerator* GetFromArgs( 75 const grpc_channel_args* args); 76 77 private: 78 friend class FakeResolver; 79 80 static void SetResponseLocked(void* arg, grpc_error* error); 81 static void SetReresolutionResponseLocked(void* arg, grpc_error* error); 82 static void SetFailureLocked(void* arg, grpc_error* error); 83 84 FakeResolver* resolver_ = nullptr; // Do not own. 85 Resolver::Result result_; 86 bool has_result_ = false; 87 }; 88 89 } // namespace grpc_core 90 91 #endif /* GRPC_CORE_EXT_FILTERS_CLIENT_CHANNEL_RESOLVER_FAKE_FAKE_RESOLVER_H \ 92 */ 93