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/*
*
* Copyright 2015 gRPC authors.
*
* 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.
*
*/
#import "GRXWriteable.h"
@implementation GRXWriteable {
GRXValueHandler _valueHandler;
GRXCompletionHandler _completionHandler;
}
+ (instancetype)writeableWithSingleHandler:(GRXSingleHandler)handler {
if (!handler) {
return [[self alloc] init];
}
// We nilify this variable when the block is invoked, so that handler is only invoked once even if
// the writer tries to write multiple values.
__block GRXEventHandler eventHandler = ^(BOOL done, id value, NSError *error) {
// Nillify eventHandler before invoking handler, in case the latter causes the former to be
// executed recursively. Because blocks can be deallocated even during execution, we have to
// first retain handler locally to guarantee it's valid.
// TODO(jcanizales): Just turn this craziness into a simple subclass of GRXWriteable.
GRXSingleHandler singleHandler = handler;
eventHandler = nil;
if (value) {
singleHandler(value, nil);
} else if (error) {
singleHandler(nil, error);
} else {
NSDictionary *userInfo =
@{NSLocalizedDescriptionKey : @"The writer finished without producing any value."};
// Even though RxLibrary is independent of gRPC, the domain and code here are, for the moment,
// set to the values of kGRPCErrorDomain and GRPCErrorCodeInternal. This way, the error formed
// is the one user of gRPC would expect if the server failed to produce a response.
//
// TODO(jcanizales): Figure out a way to keep errors of RxLibrary generic without making users
// of gRPC take care of two different error domains and error code enums. A possibility is to
// add error handling to GRXWriters or GRXWriteables, and use them to translate errors between
// the two domains.
static NSString *kGRPCErrorDomain = @"io.grpc";
static NSUInteger kGRPCErrorCodeInternal = 13;
singleHandler(
nil,
[NSError errorWithDomain:kGRPCErrorDomain code:kGRPCErrorCodeInternal userInfo:userInfo]);
}
};
return [self writeableWithEventHandler:^(BOOL done, id value, NSError *error) {
if (eventHandler) {
eventHandler(done, value, error);
}
}];
}
+ (instancetype)writeableWithEventHandler:(GRXEventHandler)handler {
if (!handler) {
return [[self alloc] init];
}
return [[self alloc] initWithValueHandler:^(id value) {
handler(NO, value, nil);
}
completionHandler:^(NSError *errorOrNil) {
handler(YES, nil, errorOrNil);
}];
}
- (instancetype)init {
return [self initWithValueHandler:nil completionHandler:nil];
}
// Designated initializer
- (instancetype)initWithValueHandler:(GRXValueHandler)valueHandler
completionHandler:(GRXCompletionHandler)completionHandler {
if ((self = [super init])) {
_valueHandler = valueHandler;
_completionHandler = completionHandler;
}
return self;
}
- (void)writeValue:(id)value {
if (_valueHandler) {
_valueHandler(value);
}
}
- (void)writesFinishedWithError:(NSError *)errorOrNil {
if (_completionHandler) {
_completionHandler(errorOrNil);
}
}
@end
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