From 35872c70ab90e2cdb8e94c1b94184f0ecd5f1325 Mon Sep 17 00:00:00 2001
From: Andrew McCreight <continuation@gmail.com>
Date: Tue, 10 Sep 2013 08:56:34 -0700
Subject: [PATCH] Bug 913527, part 3 - Check for collection in progress in
 Collect. r=smaug

Moving this to the top level simplifies dealing with PrepareForCollection a bit.
---
 xpcom/base/nsCycleCollector.cpp | 15 ++++++---------
 1 file changed, 6 insertions(+), 9 deletions(-)

diff --git a/xpcom/base/nsCycleCollector.cpp b/xpcom/base/nsCycleCollector.cpp
index 59bdcb76a966..2bbaaa3e7457 100644
--- a/xpcom/base/nsCycleCollector.cpp
+++ b/xpcom/base/nsCycleCollector.cpp
@@ -981,7 +981,7 @@ public:
                  nsCycleCollectorResults *aResults,
                  nsICycleCollectorListener *aListener);
 
-    bool PrepareForCollection(nsCycleCollectorResults *aResults,
+    void PrepareForCollection(nsCycleCollectorResults *aResults,
                               nsTArray<PtrInfo*> *aWhiteNodes);
     void FixGrayBits(bool aForceGC);
     bool ShouldMergeZones(ccType aCCType);
@@ -2599,14 +2599,10 @@ nsCycleCollector::FixGrayBits(bool aForceGC)
     timeLog.Checkpoint("GC()");
 }
 
-bool
+void
 nsCycleCollector::PrepareForCollection(nsCycleCollectorResults *aResults,
                                        nsTArray<PtrInfo*> *aWhiteNodes)
 {
-    // This can legitimately happen in a few cases. See bug 383651.
-    if (mCollectionInProgress)
-        return false;
-
     TimeLog timeLog;
 
     mCollectionStart = TimeStamp::Now();
@@ -2623,8 +2619,6 @@ nsCycleCollector::PrepareForCollection(nsCycleCollectorResults *aResults,
     mWhiteNodes = aWhiteNodes;
 
     timeLog.Checkpoint("PrepareForCollection()");
-
-    return true;
 }
 
 void
@@ -2687,10 +2681,13 @@ nsCycleCollector::Collect(ccType aCCType,
 {
     CheckThreadSafety();
 
-    if (!PrepareForCollection(aResults, aWhiteNodes)) {
+    // This can legitimately happen in a few cases. See bug 383651.
+    if (mCollectionInProgress) {
         return false;
     }
 
+    PrepareForCollection(aResults, aWhiteNodes);
+
     bool forceGC = (aCCType == ShutdownCC);
     if (!forceGC && aListener) {
         // On a WantAllTraces CC, force a synchronous global GC to prevent