From bd41a39f693d8307d407e42b634b315e075b6c8f Mon Sep 17 00:00:00 2001 From: Thomas Van Lenten Date: Mon, 21 Mar 2016 11:11:14 -0400 Subject: Only create the readonlySemaphore on demand. This will lower the amount of dispatch_semaphores created per Message when the full object tree isn't walked in a way that would require them to be created. Uses a dispatch_once_t for one time init of the dispatch_semaphore. --- objectivec/GPBMessage_PackagePrivate.h | 12 ++++++++++++ 1 file changed, 12 insertions(+) (limited to 'objectivec/GPBMessage_PackagePrivate.h') diff --git a/objectivec/GPBMessage_PackagePrivate.h b/objectivec/GPBMessage_PackagePrivate.h index b7e24fc9..478db2cf 100644 --- a/objectivec/GPBMessage_PackagePrivate.h +++ b/objectivec/GPBMessage_PackagePrivate.h @@ -67,6 +67,10 @@ typedef struct GPBMessage_Storage *GPBMessage_StoragePtr; // priority inversion: // http://mjtsai.com/blog/2015/12/16/osspinlock-is-unsafe/ // https://lists.swift.org/pipermail/swift-dev/Week-of-Mon-20151214/000372.html + // Use of readOnlySemaphore_ must be prefaced by a call to + // GPBPrepareReadOnlySemaphore to ensure it has been created. This allows + // readOnlySemaphore_ to be only created when actually needed. + dispatch_once_t readOnlySemaphoreCreationOnce_; dispatch_semaphore_t readOnlySemaphore_; } @@ -103,6 +107,14 @@ typedef struct GPBMessage_Storage *GPBMessage_StoragePtr; CF_EXTERN_C_BEGIN + +// Call this before using the readOnlySemaphore_. This ensures it is created only once. +NS_INLINE void GPBPrepareReadOnlySemaphore(GPBMessage *self) { + dispatch_once(&self->readOnlySemaphoreCreationOnce_, ^{ + self->readOnlySemaphore_ = dispatch_semaphore_create(1); + }); +} + // Returns a new instance that was automatically created by |autocreator| for // its field |field|. GPBMessage *GPBCreateMessageWithAutocreator(Class msgClass, -- cgit v1.2.3