1 /* 2 * 3 * Copyright 2015 gRPC authors. 4 * 5 * Licensed under the Apache License, Version 2.0 (the "License"); 6 * you may not use this file except in compliance with the License. 7 * You may obtain a copy of the License at 8 * 9 * http://www.apache.org/licenses/LICENSE-2.0 10 * 11 * Unless required by applicable law or agreed to in writing, software 12 * distributed under the License is distributed on an "AS IS" BASIS, 13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 14 * See the License for the specific language governing permissions and 15 * limitations under the License. 16 * 17 */ 18 19 #import <Foundation/Foundation.h> 20 21 #import "GRXWriter.h" 22 23 /** 24 * Utility to construct GRXWriter instances from values that are immediately available when 25 * required. 26 * 27 * Thread-safety: 28 * 29 * An object of this class shouldn't be messaged concurrently by more than one thread. It will start 30 * messaging the writeable before |startWithWriteable:| returns, in the same thread. That is the 31 * only place where the writer can be paused or stopped prematurely. 32 * 33 * If a paused writer of this class is resumed, it will start messaging the writeable, in the same 34 * thread, before |setState:| returns. Because the object can't be legally accessed concurrently, 35 * that's the only place where it can be paused again (or stopped). 36 */ 37 @interface GRXImmediateWriter : GRXWriter 38 39 /** 40 * Returns a writer that pulls values from the passed NSEnumerator instance and pushes them to 41 * its writeable. The NSEnumerator is released when it finishes. 42 */ 43 + (GRXWriter *)writerWithEnumerator:(NSEnumerator *)enumerator; 44 45 /** 46 * Returns a writer that pushes to its writeable the successive values returned by the passed 47 * block. When the block first returns nil, it is released. 48 */ 49 + (GRXWriter *)writerWithValueSupplier:(id (^)(void))block; 50 51 /** 52 * Returns a writer that iterates over the values of the passed container and pushes them to 53 * its writeable. The container is released when the iteration is over. 54 * 55 * Note that the usual speed gain of NSFastEnumeration over NSEnumerator results from not having to 56 * call one method per element. Because GRXWriteable instances accept values one by one, that speed 57 * gain doesn't happen here. 58 */ 59 + (GRXWriter *)writerWithContainer:(id<NSFastEnumeration>)container; 60 61 /** 62 * Returns a writer that sends the passed value to its writeable and then finishes (releasing the 63 * value). 64 */ 65 + (GRXWriter *)writerWithValue:(id)value; 66 67 /** 68 * Returns a writer that, as part of its start method, sends the passed error to the writeable 69 * (then releasing the error). 70 */ 71 + (GRXWriter *)writerWithError:(NSError *)error; 72 73 /** 74 * Returns a writer that, as part of its start method, finishes immediately without sending any 75 * values to its writeable. 76 */ 77 + (GRXWriter *)emptyWriter; 78 79 @end 80