Jorge Canizales | 9409ad8 | 2015-02-18 16:19:56 -0800 | [diff] [blame] | 1 | /* |
| 2 | * |
Yang Gao | 5fc9029 | 2015-02-20 09:46:22 -0800 | [diff] [blame] | 3 | * Copyright 2015, Google Inc. |
Jorge Canizales | 9409ad8 | 2015-02-18 16:19:56 -0800 | [diff] [blame] | 4 | * All rights reserved. |
| 5 | * |
| 6 | * Redistribution and use in source and binary forms, with or without |
| 7 | * modification, are permitted provided that the following conditions are |
| 8 | * met: |
| 9 | * |
| 10 | * * Redistributions of source code must retain the above copyright |
| 11 | * notice, this list of conditions and the following disclaimer. |
| 12 | * * Redistributions in binary form must reproduce the above |
| 13 | * copyright notice, this list of conditions and the following disclaimer |
| 14 | * in the documentation and/or other materials provided with the |
| 15 | * distribution. |
| 16 | * * Neither the name of Google Inc. nor the names of its |
| 17 | * contributors may be used to endorse or promote products derived from |
| 18 | * this software without specific prior written permission. |
| 19 | * |
| 20 | * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS |
| 21 | * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT |
| 22 | * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR |
| 23 | * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT |
| 24 | * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, |
| 25 | * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT |
| 26 | * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
| 27 | * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
| 28 | * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
| 29 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE |
| 30 | * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| 31 | * |
| 32 | */ |
| 33 | |
Jorge Canizales | 5e0efd9 | 2015-02-17 18:23:58 -0800 | [diff] [blame] | 34 | #import "GRPCCall.h" |
| 35 | |
Jorge Canizales | c2d7ecb | 2015-02-27 01:22:41 -0800 | [diff] [blame] | 36 | #include <grpc/grpc.h> |
| 37 | #include <grpc/support/grpc_time.h> |
Jorge Canizales | 5e0efd9 | 2015-02-17 18:23:58 -0800 | [diff] [blame] | 38 | |
| 39 | #import "GRPCMethodName.h" |
| 40 | #import "private/GRPCChannel.h" |
| 41 | #import "private/GRPCCompletionQueue.h" |
| 42 | #import "private/GRPCDelegateWrapper.h" |
| 43 | #import "private/GRPCMethodName+HTTP2Encoding.h" |
murgatroid99 | 69927d6 | 2015-04-24 13:32:48 -0700 | [diff] [blame^] | 44 | #import "private/GRPCWrappedCall.h" |
Jorge Canizales | 5e0efd9 | 2015-02-17 18:23:58 -0800 | [diff] [blame] | 45 | #import "private/NSData+GRPC.h" |
| 46 | #import "private/NSDictionary+GRPC.h" |
| 47 | #import "private/NSError+GRPC.h" |
| 48 | |
| 49 | // A grpc_call_error represents a precondition failure when invoking the |
| 50 | // grpc_call_* functions. If one ever happens, it's a bug in this library. |
| 51 | // |
| 52 | // TODO(jcanizales): Can an application shut down gracefully when a thread other |
| 53 | // than the main one throws an exception? |
| 54 | static void AssertNoErrorInCall(grpc_call_error error) { |
| 55 | if (error != GRPC_CALL_OK) { |
| 56 | @throw [NSException exceptionWithName:NSInternalInconsistencyException |
| 57 | reason:@"Precondition of grpc_call_* not met." |
| 58 | userInfo:nil]; |
| 59 | } |
| 60 | } |
| 61 | |
| 62 | @interface GRPCCall () <GRXWriteable> |
| 63 | // Makes it readwrite. |
| 64 | @property(atomic, strong) NSDictionary *responseMetadata; |
| 65 | @end |
| 66 | |
| 67 | // The following methods of a C gRPC call object aren't reentrant, and thus |
| 68 | // calls to them must be serialized: |
| 69 | // - add_metadata |
| 70 | // - invoke |
| 71 | // - start_write |
| 72 | // - writes_done |
| 73 | // - start_read |
| 74 | // - destroy |
| 75 | // The first four are called as part of responding to client commands, but |
| 76 | // start_read we want to call as soon as we're notified that the RPC was |
| 77 | // successfully established (which happens concurrently in the network queue). |
| 78 | // Serialization is achieved by using a private serial queue to operate the |
| 79 | // call object. |
| 80 | // Because add_metadata and invoke are called and return successfully before |
| 81 | // any of the other methods is called, they don't need to use the queue. |
| 82 | // |
| 83 | // Furthermore, start_write and writes_done can only be called after the |
| 84 | // WRITE_ACCEPTED event for any previous write is received. This is achieved by |
| 85 | // pausing the requests writer immediately every time it writes a value, and |
| 86 | // resuming it again when WRITE_ACCEPTED is received. |
| 87 | // |
| 88 | // Similarly, start_read can only be called after the READ event for any |
| 89 | // previous read is received. This is easier to enforce, as we're writing the |
| 90 | // received messages into the writeable: start_read is enqueued once upon receiving |
| 91 | // the CLIENT_METADATA_READ event, and then once after receiving each READ |
| 92 | // event. |
| 93 | @implementation GRPCCall { |
| 94 | dispatch_queue_t _callQueue; |
| 95 | |
murgatroid99 | 30b7d4e | 2015-04-24 10:36:43 -0700 | [diff] [blame] | 96 | GRPCWrappedCall *_wrappedCall; |
Jorge Canizales | 5e0efd9 | 2015-02-17 18:23:58 -0800 | [diff] [blame] | 97 | dispatch_once_t _callAlreadyInvoked; |
| 98 | |
| 99 | GRPCChannel *_channel; |
| 100 | GRPCCompletionQueue *_completionQueue; |
| 101 | |
| 102 | // The C gRPC library has less guarantees on the ordering of events than we |
| 103 | // do. Particularly, in the face of errors, there's no ordering guarantee at |
| 104 | // all. This wrapper over our actual writeable ensures thread-safety and |
| 105 | // correct ordering. |
| 106 | GRPCDelegateWrapper *_responseWriteable; |
| 107 | id<GRXWriter> _requestWriter; |
| 108 | } |
| 109 | |
| 110 | @synthesize state = _state; |
| 111 | |
| 112 | - (instancetype)init { |
| 113 | return [self initWithHost:nil method:nil requestsWriter:nil]; |
| 114 | } |
| 115 | |
| 116 | // Designated initializer |
| 117 | - (instancetype)initWithHost:(NSString *)host |
| 118 | method:(GRPCMethodName *)method |
| 119 | requestsWriter:(id<GRXWriter>)requestWriter { |
| 120 | if (!host || !method) { |
| 121 | [NSException raise:NSInvalidArgumentException format:@"Neither host nor method can be nil."]; |
| 122 | } |
| 123 | // TODO(jcanizales): Throw if the requestWriter was already started. |
| 124 | if ((self = [super init])) { |
| 125 | static dispatch_once_t initialization; |
| 126 | dispatch_once(&initialization, ^{ |
| 127 | grpc_init(); |
| 128 | }); |
| 129 | |
| 130 | _completionQueue = [GRPCCompletionQueue completionQueue]; |
| 131 | |
| 132 | _channel = [GRPCChannel channelToHost:host]; |
murgatroid99 | 30b7d4e | 2015-04-24 10:36:43 -0700 | [diff] [blame] | 133 | |
| 134 | _wrappedCall = [[GRPCWrappedCall alloc] initWithChannel:_channel method:method.HTTP2Path host:host]; |
Jorge Canizales | 5e0efd9 | 2015-02-17 18:23:58 -0800 | [diff] [blame] | 135 | |
| 136 | // Serial queue to invoke the non-reentrant methods of the grpc_call object. |
| 137 | _callQueue = dispatch_queue_create("org.grpc.call", NULL); |
| 138 | |
| 139 | _requestWriter = requestWriter; |
| 140 | } |
| 141 | return self; |
| 142 | } |
| 143 | |
| 144 | #pragma mark Finish |
| 145 | |
| 146 | - (void)finishWithError:(NSError *)errorOrNil { |
| 147 | _requestWriter.state = GRXWriterStateFinished; |
| 148 | _requestWriter = nil; |
| 149 | if (errorOrNil) { |
| 150 | [_responseWriteable cancelWithError:errorOrNil]; |
| 151 | } else { |
| 152 | [_responseWriteable enqueueSuccessfulCompletion]; |
| 153 | } |
| 154 | } |
| 155 | |
| 156 | - (void)cancelCall { |
| 157 | // Can be called from any thread, any number of times. |
murgatroid99 | 30b7d4e | 2015-04-24 10:36:43 -0700 | [diff] [blame] | 158 | [_wrappedCall cancel]; |
Jorge Canizales | 5e0efd9 | 2015-02-17 18:23:58 -0800 | [diff] [blame] | 159 | } |
| 160 | |
| 161 | - (void)cancel { |
| 162 | [self finishWithError:[NSError errorWithDomain:kGRPCErrorDomain |
| 163 | code:GRPCErrorCodeCancelled |
| 164 | userInfo:nil]]; |
| 165 | [self cancelCall]; |
| 166 | } |
| 167 | |
| 168 | - (void)dealloc { |
Jorge Canizales | 5e0efd9 | 2015-02-17 18:23:58 -0800 | [diff] [blame] | 169 | dispatch_async(_callQueue, ^{ |
murgatroid99 | 30b7d4e | 2015-04-24 10:36:43 -0700 | [diff] [blame] | 170 | _wrappedCall = nil; |
Jorge Canizales | 5e0efd9 | 2015-02-17 18:23:58 -0800 | [diff] [blame] | 171 | }); |
| 172 | } |
| 173 | |
| 174 | #pragma mark Read messages |
| 175 | |
| 176 | // Only called from the call queue. |
| 177 | // The handler will be called from the network queue. |
murgatroid99 | 30b7d4e | 2015-04-24 10:36:43 -0700 | [diff] [blame] | 178 | - (void)startReadWithHandler:(GRPCCompletionHandler)handler { |
murgatroid99 | 69927d6 | 2015-04-24 13:32:48 -0700 | [diff] [blame^] | 179 | [_wrappedCall startBatchWithOperations:@{@(GRPC_OP_RECV_MESSAGE): @YES} handleCompletion:handler]; |
Jorge Canizales | 5e0efd9 | 2015-02-17 18:23:58 -0800 | [diff] [blame] | 180 | } |
| 181 | |
| 182 | // Called initially from the network queue once response headers are received, |
| 183 | // then "recursively" from the responseWriteable queue after each response from the |
| 184 | // server has been written. |
| 185 | // If the call is currently paused, this is a noop. Restarting the call will invoke this |
| 186 | // method. |
| 187 | // TODO(jcanizales): Rename to readResponseIfNotPaused. |
| 188 | - (void)startNextRead { |
| 189 | if (self.state == GRXWriterStatePaused) { |
| 190 | return; |
| 191 | } |
| 192 | __weak GRPCCall *weakSelf = self; |
| 193 | __weak GRPCDelegateWrapper *weakWriteable = _responseWriteable; |
murgatroid99 | 69927d6 | 2015-04-24 13:32:48 -0700 | [diff] [blame^] | 194 | |
Jorge Canizales | 5e0efd9 | 2015-02-17 18:23:58 -0800 | [diff] [blame] | 195 | dispatch_async(_callQueue, ^{ |
murgatroid99 | 69927d6 | 2015-04-24 13:32:48 -0700 | [diff] [blame^] | 196 | [weakSelf startReadWithHandler:^(NSDictionary *result) { |
| 197 | NSData *data = result[@(GRPC_OP_RECV_MESSAGE)]; |
murgatroid99 | 30b7d4e | 2015-04-24 10:36:43 -0700 | [diff] [blame] | 198 | if (data == [NSNull null]) { |
Jorge Canizales | 5e0efd9 | 2015-02-17 18:23:58 -0800 | [diff] [blame] | 199 | return; |
| 200 | } |
Jorge Canizales | 5e0efd9 | 2015-02-17 18:23:58 -0800 | [diff] [blame] | 201 | if (!data) { |
| 202 | // The app doesn't have enough memory to hold the server response. We |
| 203 | // don't want to throw, because the app shouldn't crash for a behavior |
| 204 | // that's on the hands of any server to have. Instead we finish and ask |
| 205 | // the server to cancel. |
| 206 | // |
| 207 | // TODO(jcanizales): No canonical code is appropriate for this situation |
| 208 | // (because it's just a client problem). Use another domain and an |
| 209 | // appropriately-documented code. |
| 210 | [weakSelf finishWithError:[NSError errorWithDomain:kGRPCErrorDomain |
| 211 | code:GRPCErrorCodeInternal |
| 212 | userInfo:nil]]; |
| 213 | [weakSelf cancelCall]; |
| 214 | return; |
| 215 | } |
| 216 | [weakWriteable enqueueMessage:data completionHandler:^{ |
| 217 | [weakSelf startNextRead]; |
| 218 | }]; |
| 219 | }]; |
| 220 | }); |
| 221 | } |
| 222 | |
| 223 | #pragma mark Send headers |
| 224 | |
murgatroid99 | 69927d6 | 2015-04-24 13:32:48 -0700 | [diff] [blame^] | 225 | // TODO(jcanizales): Rename to commitHeaders. |
Jorge Canizales | 5e0efd9 | 2015-02-17 18:23:58 -0800 | [diff] [blame] | 226 | - (void)sendHeaders:(NSDictionary *)metadata { |
murgatroid99 | 69927d6 | 2015-04-24 13:32:48 -0700 | [diff] [blame^] | 227 | [_wrappedCall startBatchWithOperations:@{@(GRPC_OP_SEND_INITIAL_METADATA): metadata?:@{}} handleCompletion:nil]; |
Jorge Canizales | 5e0efd9 | 2015-02-17 18:23:58 -0800 | [diff] [blame] | 228 | } |
| 229 | |
| 230 | #pragma mark GRXWriteable implementation |
| 231 | |
| 232 | // Only called from the call queue. The error handler will be called from the |
| 233 | // network queue if the write didn't succeed. |
| 234 | - (void)writeMessage:(NSData *)message withErrorHandler:(void (^)())errorHandler { |
| 235 | |
| 236 | __weak GRPCCall *weakSelf = self; |
murgatroid99 | 69927d6 | 2015-04-24 13:32:48 -0700 | [diff] [blame^] | 237 | GRPCCompletionHandler resumingHandler = ^(NSDictionary *result) { |
Jorge Canizales | 5e0efd9 | 2015-02-17 18:23:58 -0800 | [diff] [blame] | 238 | // Resume the request writer (even in the case of error). |
| 239 | // TODO(jcanizales): No need to do it in the case of errors anymore? |
| 240 | GRPCCall *strongSelf = weakSelf; |
| 241 | if (strongSelf) { |
| 242 | strongSelf->_requestWriter.state = GRXWriterStateStarted; |
| 243 | } |
| 244 | }; |
murgatroid99 | 69927d6 | 2015-04-24 13:32:48 -0700 | [diff] [blame^] | 245 | [_wrappedCall startBatchWithOperations:@{@(GRPC_OP_SEND_MESSAGE): message} handleCompletion:resumingHandler errorHandler:errorHandler]; |
Jorge Canizales | 5e0efd9 | 2015-02-17 18:23:58 -0800 | [diff] [blame] | 246 | } |
| 247 | |
| 248 | - (void)didReceiveValue:(id)value { |
| 249 | // TODO(jcanizales): Throw/assert if value isn't NSData. |
| 250 | |
| 251 | // Pause the input and only resume it when the C layer notifies us that writes |
| 252 | // can proceed. |
| 253 | _requestWriter.state = GRXWriterStatePaused; |
| 254 | |
| 255 | __weak GRPCCall *weakSelf = self; |
| 256 | dispatch_async(_callQueue, ^{ |
| 257 | [weakSelf writeMessage:value withErrorHandler:^{ |
| 258 | [weakSelf finishWithError:[NSError errorWithDomain:kGRPCErrorDomain |
| 259 | code:GRPCErrorCodeInternal |
| 260 | userInfo:nil]]; |
| 261 | }]; |
| 262 | }); |
| 263 | } |
| 264 | |
| 265 | // Only called from the call queue. The error handler will be called from the |
| 266 | // network queue if the requests stream couldn't be closed successfully. |
| 267 | - (void)finishRequestWithErrorHandler:(void (^)())errorHandler { |
murgatroid99 | 69927d6 | 2015-04-24 13:32:48 -0700 | [diff] [blame^] | 268 | [_wrappedCall startBatchWithOperations:@{@(GRPC_OP_SEND_CLOSE_FROM_CLIENT): @YES} handleCompletion:nil errorHandler:errorHandler]; |
Jorge Canizales | 5e0efd9 | 2015-02-17 18:23:58 -0800 | [diff] [blame] | 269 | } |
| 270 | |
| 271 | - (void)didFinishWithError:(NSError *)errorOrNil { |
| 272 | if (errorOrNil) { |
| 273 | [self cancel]; |
| 274 | } else { |
| 275 | __weak GRPCCall *weakSelf = self; |
| 276 | dispatch_async(_callQueue, ^{ |
| 277 | [weakSelf finishRequestWithErrorHandler:^{ |
| 278 | [weakSelf finishWithError:[NSError errorWithDomain:kGRPCErrorDomain |
| 279 | code:GRPCErrorCodeInternal |
| 280 | userInfo:nil]]; |
| 281 | }]; |
| 282 | }); |
| 283 | } |
| 284 | } |
| 285 | |
| 286 | #pragma mark Invoke |
| 287 | |
| 288 | // Both handlers will eventually be called, from the network queue. Writes can start immediately |
| 289 | // after this. |
| 290 | // The first one (metadataHandler), when the response headers are received. |
| 291 | // The second one (completionHandler), whenever the RPC finishes for any reason. |
murgatroid99 | 30b7d4e | 2015-04-24 10:36:43 -0700 | [diff] [blame] | 292 | - (void)invokeCallWithMetadataHandler:(GRPCCompletionHandler)metadataHandler |
| 293 | completionHandler:(GRPCCompletionHandler)completionHandler { |
murgatroid99 | 69927d6 | 2015-04-24 13:32:48 -0700 | [diff] [blame^] | 294 | [_wrappedCall startBatchWithOperations:@{@(GRPC_OP_RECV_INITIAL_METADATA): @YES} handleCompletion:metadataHandler]; |
| 295 | [_wrappedCall startBatchWithOperations:@{@(GRPC_OP_RECV_STATUS_ON_CLIENT): @YES} handleCompletion:completionHandler]; |
Jorge Canizales | 5e0efd9 | 2015-02-17 18:23:58 -0800 | [diff] [blame] | 296 | } |
| 297 | |
| 298 | - (void)invokeCall { |
| 299 | __weak GRPCCall *weakSelf = self; |
murgatroid99 | 69927d6 | 2015-04-24 13:32:48 -0700 | [diff] [blame^] | 300 | [self invokeCallWithMetadataHandler:^(NSDictionary *result) { |
Jorge Canizales | 5e0efd9 | 2015-02-17 18:23:58 -0800 | [diff] [blame] | 301 | // Response metadata received. |
Jorge Canizales | 5e0efd9 | 2015-02-17 18:23:58 -0800 | [diff] [blame] | 302 | GRPCCall *strongSelf = weakSelf; |
| 303 | if (strongSelf) { |
murgatroid99 | 69927d6 | 2015-04-24 13:32:48 -0700 | [diff] [blame^] | 304 | strongSelf.responseMetadata = result[@(GRPC_OP_RECV_INITIAL_METADATA)]; |
Jorge Canizales | 5e0efd9 | 2015-02-17 18:23:58 -0800 | [diff] [blame] | 305 | [strongSelf startNextRead]; |
| 306 | } |
murgatroid99 | 69927d6 | 2015-04-24 13:32:48 -0700 | [diff] [blame^] | 307 | } completionHandler:^(NSDictionary *result) { |
Jorge Canizales | 5e0efd9 | 2015-02-17 18:23:58 -0800 | [diff] [blame] | 308 | // TODO(jcanizales): Merge HTTP2 trailers into response metadata. |
murgatroid99 | 69927d6 | 2015-04-24 13:32:48 -0700 | [diff] [blame^] | 309 | id error = result[@(GRPC_OP_RECV_STATUS_ON_CLIENT)]; |
murgatroid99 | 30b7d4e | 2015-04-24 10:36:43 -0700 | [diff] [blame] | 310 | if (error == [NSNull null]) { |
| 311 | error = nil; |
| 312 | } |
| 313 | [weakSelf finishWithError:error]; |
Jorge Canizales | 5e0efd9 | 2015-02-17 18:23:58 -0800 | [diff] [blame] | 314 | }]; |
| 315 | // Now that the RPC has been initiated, request writes can start. |
| 316 | [_requestWriter startWithWriteable:self]; |
| 317 | } |
| 318 | |
| 319 | #pragma mark GRXWriter implementation |
| 320 | |
| 321 | - (void)startWithWriteable:(id<GRXWriteable>)writeable { |
| 322 | // The following produces a retain cycle self:_responseWriteable:self, which is only |
| 323 | // broken when didFinishWithError: is sent to the wrapped writeable. |
| 324 | // Care is taken not to retain self strongly in any of the blocks used in |
| 325 | // the implementation of GRPCCall, so that the life of the instance is |
| 326 | // determined by this retain cycle. |
| 327 | _responseWriteable = [[GRPCDelegateWrapper alloc] initWithWriteable:writeable writer:self]; |
| 328 | [self sendHeaders:_requestMetadata]; |
| 329 | [self invokeCall]; |
| 330 | } |
| 331 | |
| 332 | - (void)setState:(GRXWriterState)newState { |
| 333 | // Manual transitions are only allowed from the started or paused states. |
| 334 | if (_state == GRXWriterStateNotStarted || _state == GRXWriterStateFinished) { |
| 335 | return; |
| 336 | } |
| 337 | |
| 338 | switch (newState) { |
| 339 | case GRXWriterStateFinished: |
| 340 | _state = newState; |
| 341 | // Per GRXWriter's contract, setting the state to Finished manually |
| 342 | // means one doesn't wish the writeable to be messaged anymore. |
| 343 | [_responseWriteable cancelSilently]; |
| 344 | _responseWriteable = nil; |
| 345 | return; |
| 346 | case GRXWriterStatePaused: |
| 347 | _state = newState; |
| 348 | return; |
| 349 | case GRXWriterStateStarted: |
| 350 | if (_state == GRXWriterStatePaused) { |
| 351 | _state = newState; |
| 352 | [self startNextRead]; |
| 353 | } |
| 354 | return; |
| 355 | case GRXWriterStateNotStarted: |
| 356 | return; |
| 357 | } |
| 358 | } |
| 359 | @end |