From 8b414f184db9295e30164140d54357c6ad310368 Mon Sep 17 00:00:00 2001
From: Jorge Canizales <jcanizales@google.com>
Date: Fri, 11 Mar 2016 10:28:40 -0800
Subject: [PATCH] Clean up ownership of the connection loss handler
---
.../private/GRPCConnectivityMonitor.h | 2 +-
.../private/GRPCConnectivityMonitor.m | 22 +++++++++++--------
2 files changed, 14 insertions(+), 10 deletions(-)
diff --git a/src/objective-c/GRPCClient/private/GRPCConnectivityMonitor.h b/src/objective-c/GRPCClient/private/GRPCConnectivityMonitor.h
index d9d6c22ae9..2fae410331 100644
--- a/src/objective-c/GRPCClient/private/GRPCConnectivityMonitor.h
+++ b/src/objective-c/GRPCClient/private/GRPCConnectivityMonitor.h
@@ -68,7 +68,7 @@
@property(nonatomic, strong, null_resettable) dispatch_queue_t queue;
/**
- * Calls handler the next time the connectivity to this instance's host is lost. If this instance is
+ * Calls handler every time the connectivity to this instance's host is lost. If this instance is
* released before that happens, the handler won't be called.
* Only one handler is active at a time, so if this method is called again before the previous
* handler has been called, it might never be called at all (or yes, if it has already been queued).
diff --git a/src/objective-c/GRPCClient/private/GRPCConnectivityMonitor.m b/src/objective-c/GRPCClient/private/GRPCConnectivityMonitor.m
index f66a77c9b2..b4061bd5ef 100644
--- a/src/objective-c/GRPCClient/private/GRPCConnectivityMonitor.m
+++ b/src/objective-c/GRPCClient/private/GRPCConnectivityMonitor.m
@@ -106,13 +106,16 @@
#pragma mark Connectivity Monitor
-// Assumes the third argument is a block that accepts SCNetworkReachabilityFlags, and passes the
+// Assumes the third argument is a block that accepts a GRPCReachabilityFlags object, and passes the
// received ones to it.
static void PassFlagsToContextInfoBlock(SCNetworkReachabilityRef target,
SCNetworkReachabilityFlags flags,
void *info) {
#pragma unused (target)
- ((__bridge void (^)(SCNetworkReachabilityFlags))info)(flags);
+ // This can be called many times with the same info. The info is retained by SCNetworkReachability
+ // while this function is being executed.
+ void (^handler)(GRPCReachabilityFlags *) = (__bridge void (^)(GRPCReachabilityFlags *))info;
+ handler([[GRPCReachabilityFlags alloc] initWithFlags:flags]);
}
@implementation GRPCConnectivityMonitor {
@@ -147,29 +150,30 @@ static void PassFlagsToContextInfoBlock(SCNetworkReachabilityRef target,
}
- (void)handleLossWithHandler:(void (^)())handler {
- __weak typeof(self) weakSelf = self;
[self startListeningWithHandler:^(GRPCReachabilityFlags *flags) {
if (!flags.isHostReachable) {
- [weakSelf stopListening];
handler();
}
}];
}
- (void)startListeningWithHandler:(void (^)(GRPCReachabilityFlags *))handler {
+ // Copy to ensure the handler block is in the heap (and so can't be deallocated when this method
+ // returns).
+ void (^copiedHandler)(GRPCReachabilityFlags *) = [handler copy];
SCNetworkReachabilityContext context = {
.version = 0,
- .info = (__bridge_retained void *)^(SCNetworkReachabilityFlags flags){
- // Pass the flags as as Objective-C wrapper.
- handler([[GRPCReachabilityFlags alloc] initWithFlags:flags]);
- },
- .release = CFRelease
+ .info = (__bridge void *)copiedHandler,
+ .retain = CFRetain,
+ .release = CFRelease,
};
+ // The following will retain context.info, and release it when the callback is set to NULL.
SCNetworkReachabilitySetCallback(_reachabilityRef, PassFlagsToContextInfoBlock, &context);
SCNetworkReachabilitySetDispatchQueue(_reachabilityRef, _queue);
}
- (void)stopListening {
+ // This releases the block on context.info.
SCNetworkReachabilitySetCallback(_reachabilityRef, NULL, NULL);
SCNetworkReachabilitySetDispatchQueue(_reachabilityRef, NULL);
}
--
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