Make the call retain cycle explicit and encapsulated within GRPCCall.m

1 files changed, 15 insertions, 25 deletions

diff --git a/src/objective-c/RxLibrary/GRXConcurrentWriteable.m b/src/objective-c/RxLibrary/GRXConcurrentWriteable.m
index 735df3137b..08bd079aea 100644
--- a/src/objective-c/RxLibrary/GRXConcurrentWriteable.m
+++ b/src/objective-c/RxLibrary/GRXConcurrentWriteable.m
@@ -36,9 +36,8 @@
 #import <RxLibrary/GRXWriteable.h>
 
 @interface GRXConcurrentWriteable ()
-// These are atomic so that cancellation can nillify them from any thread.
+// This is atomic so that cancellation can nillify it from any thread.
 @property(atomic, strong) id<GRXWriteable> writeable;
-@property(atomic, strong) GRXWriter *writer;
 @end
 
 @implementation GRXConcurrentWriteable {
@@ -48,25 +47,23 @@
 }
 
 - (instancetype)init {
-  return [self initWithWriteable:nil writer:nil];
+  return [self initWithWriteable:nil];
 }
 
 // Designated initializer
-- (instancetype)initWithWriteable:(id<GRXWriteable>)writeable writer:(GRXWriter *)writer {
+- (instancetype)initWithWriteable:(id<GRXWriteable>)writeable {
   if (self = [super init]) {
     _writeableQueue = dispatch_get_main_queue();
     _writeable = writeable;
-    _writer = writer;
   }
   return self;
 }
 
 - (void)enqueueValue:(id)value completionHandler:(void (^)())handler {
   dispatch_async(_writeableQueue, ^{
-    // We're racing a possible cancellation performed by another thread. To turn
-    // all already-enqueued messages into noops, cancellation nillifies the
-    // writeable property. If we get it before it's nil, we won
-    // the race.
+    // We're racing a possible cancellation performed by another thread. To turn all already-
+    // enqueued messages into noops, cancellation nillifies the writeable property. If we get it
+    // before it's nil, we won the race.
     id<GRXWriteable> writeable = self.writeable;
     if (writeable) {
       [writeable writeValue:value];
@@ -78,13 +75,11 @@
 - (void)enqueueSuccessfulCompletion {
   dispatch_async(_writeableQueue, ^{
     dispatch_once(&_alreadyFinished, ^{
-      // Cancellation is now impossible. None of the other three blocks can run
-      // concurrently with this one.
+      // Cancellation is now impossible. None of the other three blocks can run concurrently with
+      // this one.
       [self.writeable writesFinishedWithError:nil];
-      // Break the retain cycle with writer, and skip any possible message to the
-      // wrapped writeable enqueued after this one.
+      // Skip any possible message to the wrapped writeable enqueued after this one.
       self.writeable = nil;
-      self.writer = nil;
     });
   });
 }
@@ -92,29 +87,24 @@
 - (void)cancelWithError:(NSError *)error {
   NSAssert(error, @"For a successful completion, use enqueueSuccessfulCompletion.");
   dispatch_once(&_alreadyFinished, ^{
-    // Skip any of the still-enqueued messages to the wrapped writeable. We use
-    // the atomic setter to nillify writer and writeable because we might be
-    // running concurrently with the blocks in _writeableQueue, and assignment
-    // with ARC isn't atomic.
+    // Skip any of the still-enqueued messages to the wrapped writeable. We use the atomic setter to
+    // nillify writeable because we might be running concurrently with the blocks in
+    // _writeableQueue, and assignment with ARC isn't atomic.
     id<GRXWriteable> writeable = self.writeable;
     self.writeable = nil;
 
     dispatch_async(_writeableQueue, ^{
       [writeable writesFinishedWithError:error];
-      // Break the retain cycle with writer.
-      self.writer = nil;
     });
   });
 }
 
 - (void)cancelSilently {
   dispatch_once(&_alreadyFinished, ^{
-    // Skip any of the still-enqueued messages to the wrapped writeable. We use
-    // the atomic setter to nillify writer and writeable because we might be
-    // running concurrently with the blocks in _writeableQueue, and assignment
-    // with ARC isn't atomic.
+    // Skip any of the still-enqueued messages to the wrapped writeable. We use the atomic setter to
+    // nillify writeable because we might be running concurrently with the blocks in
+    // _writeableQueue, and assignment with ARC isn't atomic.
     self.writeable = nil;
-    self.writer = nil;
   });
 }
 @end