From ac7ea6f3f61d2aae8307a01b24aaa0e3277b2bb2 Mon Sep 17 00:00:00 2001
From: Ben Kelly <ben@wanderview.com>
Date: Mon, 4 Jun 2018 09:26:51 -0700
Subject: [PATCH] Bug 1441932 P4 Treat same-value assignments to the LoadInfo
 reserved and initial ClientInfo values as no-op changes. r=mayhemer

---
 dom/clients/manager/ClientInfo.cpp |  6 ++++++
 dom/clients/manager/ClientInfo.h   |  3 +++
 netwerk/base/LoadInfo.cpp          | 10 ++++++++++
 3 files changed, 19 insertions(+)

diff --git a/dom/clients/manager/ClientInfo.cpp b/dom/clients/manager/ClientInfo.cpp
index 3dfd77cf06cc..436fe3125503 100644
--- a/dom/clients/manager/ClientInfo.cpp
+++ b/dom/clients/manager/ClientInfo.cpp
@@ -60,6 +60,12 @@ ClientInfo::~ClientInfo()
 {
 }
 
+bool
+ClientInfo::operator==(const ClientInfo& aRight) const
+{
+  return *mData == *aRight.mData;
+}
+
 const nsID&
 ClientInfo::Id() const
 {
diff --git a/dom/clients/manager/ClientInfo.h b/dom/clients/manager/ClientInfo.h
index 1a983600df08..7642d92e08d5 100644
--- a/dom/clients/manager/ClientInfo.h
+++ b/dom/clients/manager/ClientInfo.h
@@ -47,6 +47,9 @@ public:
 
   ~ClientInfo();
 
+  bool
+  operator==(const ClientInfo& aRight) const;
+
   // Get the unique identifier chosen at the time of the global's creation.
   const nsID&
   Id() const;
diff --git a/netwerk/base/LoadInfo.cpp b/netwerk/base/LoadInfo.cpp
index 58b6c1df4b9a..6a6814bd9884 100644
--- a/netwerk/base/LoadInfo.cpp
+++ b/netwerk/base/LoadInfo.cpp
@@ -1317,6 +1317,11 @@ void
 LoadInfo::SetReservedClientInfo(const ClientInfo& aClientInfo)
 {
   MOZ_DIAGNOSTIC_ASSERT(mInitialClientInfo.isNothing());
+  // Treat assignments of the same value as a no-op.  The emplace below
+  // will normally assert when overwriting an existing value.
+  if (mReservedClientInfo.isSome() && mReservedClientInfo.ref() == aClientInfo) {
+    return;
+  }
   mReservedClientInfo.emplace(aClientInfo);
 }
 
@@ -1331,6 +1336,11 @@ LoadInfo::SetInitialClientInfo(const ClientInfo& aClientInfo)
 {
   MOZ_DIAGNOSTIC_ASSERT(!mReservedClientSource);
   MOZ_DIAGNOSTIC_ASSERT(mReservedClientInfo.isNothing());
+  // Treat assignments of the same value as a no-op.  The emplace below
+  // will normally assert when overwriting an existing value.
+  if (mInitialClientInfo.isSome() && mInitialClientInfo.ref() == aClientInfo) {
+    return;
+  }
   mInitialClientInfo.emplace(aClientInfo);
 }