Merge pull request #1032 from leapmotion/fix-approx-use_count

Workaround approximate use_count in std::shared_ptr

src/autotesting/AutowiringEnclosure.h

@@ -5,6 +5,7 @@
 #include <autowiring/demangle.h>
 #include <autowiring/at_exit.h>
 #include MEMORY_HEADER
+#include THREAD_HEADER
 
 #ifndef GTEST_INCLUDE_GTEST_GTEST_H_
 #error Please include your version of gtest.h before including the autowiring enclosure
@@ -50,15 +51,25 @@ struct TestInfoProxy {
 };
 
 namespace autowiring {
-  namespace testing {
+  namespace autotesting {
     struct hung {
       CoreContext& ctxt;
     };
 
-    std::ostream& operator<<(std::ostream& os, const hung& lhs) {
+    inline std::ostream& operator<<(std::ostream& os, const hung& lhs) {
       autowiring::dbg::PrintRunnables(os, lhs.ctxt);
       return os;
     }
+
+    template<typename T, typename Duration>
+    inline bool WaitForUseCount(const T& type, long useCount, Duration duration) {
+      const auto limit = std::chrono::steady_clock::now() + duration;
+      do {
+        if (useCount == type.use_count()) return true;
+        std::this_thread::yield();
+      } while (std::chrono::steady_clock::now() < limit);
+      return false;
+    }
   }
 }
 
@@ -135,7 +146,7 @@ class AutowiringEnclosure:
       // Do not allow teardown to take more than 5 seconds.  This is considered a "timely teardown" limit.
       // If it takes more than this amount of time to tear down, the test case itself should invoke SignalShutdown
       // and Wait itself with the extended teardown period specified.
-      ASSERT_TRUE(ctxt->Wait(std::chrono::seconds(5))) << "Test case took too long to tear down, unit tests running after this point are untrustworthy.  Runnable dump:\n" << autowiring::testing::hung{ *ctxt };
+      ASSERT_TRUE(ctxt->Wait(std::chrono::seconds(5))) << "Test case took too long to tear down, unit tests running after this point are untrustworthy.  Runnable dump:\n" << autowiring::autotesting::hung{ *ctxt };
 
       // Global context should return to quiescence:
       if (!allowGlobalReferences)
@@ -151,7 +162,7 @@ class AutowiringEnclosure:
     }
 
     // No more references to this context except for the pointer we hold ourselves
-    ASSERT_TRUE(ctxt.unique()) << "Detected a dangling context reference after test termination, context may be leaking";
+    ASSERT_TRUE(autowiring::autotesting::WaitForUseCount(ctxt, 1L, std::chrono::seconds(5))) << "Detected a dangling context reference after test termination, context may be leaking";
     ctxt = {};
   }
 };

src/autowiring/test/ContextCleanupTest.cpp

@@ -2,6 +2,7 @@
 #include "stdafx.h"
 #include "TestFixtures/SimpleObject.hpp"
 #include "TestFixtures/SimpleThreaded.hpp"
+#include "autotesting/AutowiringEnclosure.h"
 #include <autowiring/autowiring.h>
 #include <autowiring/CoreContext.h>
 #include THREAD_HEADER
@@ -19,7 +20,7 @@ TEST_F(ContextCleanupTest, ValidateTeardownOrder) {
 
     std::weak_ptr<WeakPtrChecker> self;
   };
-  
+
   // Construct, the destroy
   std::make_shared<WeakPtrChecker>();
 }
@@ -227,6 +228,5 @@ TEST_F(ContextCleanupTest, VerifyThreadShutdownInterleave) {
   ctxt->SignalShutdown(true);
 
   // At this point, the thread must have returned AND released its shared pointer to the enclosing context
-  ASSERT_EQ(initCount, ctxt.use_count()) << "Context thread persisted even after it should have fallen out of scope";
+  ASSERT_TRUE(autowiring::autotesting::WaitForUseCount(ctxt, initCount, std::chrono::seconds(5))) << "Context thread persisted even after it should have fallen out of scope";
 }
-

src/autowiring/test/ContextMapTest.cpp

@@ -2,6 +2,7 @@
 #include "stdafx.h"
 #include "TestFixtures/ExitRaceThreaded.hpp"
 #include "TestFixtures/SimpleThreaded.hpp"
+#include "autotesting/AutowiringEnclosure.h"
 #include <autowiring/autowiring.h>
 #include <autowiring/ContextMap.h>
 #include <string>
@@ -76,11 +77,11 @@ TEST_F(ContextMapTest, VerifyWithThreads) {
     // Terminate whole context, wait for it to respond
     context->SignalShutdown();
     context->Wait();
-    ASSERT_EQ(1UL, context.use_count()) << "Context reference should have been unique after thread expiration";
+    ASSERT_TRUE(autowiring::autotesting::WaitForUseCount(context, 1L, std::chrono::seconds(5))) << "Context reference should have been unique after thread expiration";
   }
 
   // Release our threaded entity:
-  ASSERT_EQ(1UL, threaded.use_count()) << "Thread was holding a self-reference even after context termination has completed";
+  ASSERT_TRUE(autowiring::autotesting::WaitForUseCount(threaded, 1L, std::chrono::seconds(5))) << "Thread was holding a self-reference even after context termination has completed";
   threaded.reset();
   ASSERT_TRUE(weakContext.expired()) << "Context still existed even after the last reference to it should have been gone";
 

src/autowiring/test/CoreThreadTest.cpp

@@ -1,6 +1,7 @@
 // Copyright (C) 2012-2017 Leap Motion, Inc. All rights reserved.
 #include "stdafx.h"
 #include "TestFixtures/SimpleThreaded.hpp"
+#include "autotesting/AutowiringEnclosure.h"
 #include <autowiring/at_exit.h>
 #include <autowiring/autowiring.h>
 #include <algorithm>
@@ -570,7 +571,7 @@ TEST_F(CoreThreadTest, ContextWaitTimesOutInOnStop) {
   // Let BIOS back out now:
   bios->Continue();
   ASSERT_TRUE(ctxt->Wait(std::chrono::seconds(5))) << "Context did not complete in a timely fashion";
-  ASSERT_EQ(2UL, ctxt.use_count()) << "Entity held a context shared pointer after teardown has taken place";
+  ASSERT_TRUE(autowiring::autotesting::WaitForUseCount(ctxt, 2L, std::chrono::seconds(5))) << "Entity held a context shared pointer after teardown has taken place";
 }
 
 TEST_F(CoreThreadTest, SubContextHoldsParentContext) {