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/*
*
* Copyright 2015, Google Inc.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are
* met:
*
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above
* copyright notice, this list of conditions and the following disclaimer
* in the documentation and/or other materials provided with the
* distribution.
* * Neither the name of Google Inc. nor the names of its
* contributors may be used to endorse or promote products derived from
* this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
*/
#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.
singleHandler(nil, [NSError errorWithDomain:@"io.grpc" code:13 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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