From 1e51d01858f8cd387cecf1fce7be206178796878 Mon Sep 17 00:00:00 2001
From: Nicholas Nethercote <nnethercote@mozilla.com>
Date: Sun, 31 Aug 2014 20:36:26 -0700
Subject: [PATCH] Bug 1061024 (part 1) - Don't run DMD when about:memory's
 "Measure" button is pressed. r=jld.

--HG--
extra : rebase_source : ddf0236352c64eb9839dfd0a219451a568aba10e
---
 dom/ipc/ContentParent.cpp              | 20 +++++++++++---------
 xpcom/base/nsMemoryReporterManager.cpp | 12 +++++++-----
 2 files changed, 18 insertions(+), 14 deletions(-)

diff --git a/dom/ipc/ContentParent.cpp b/dom/ipc/ContentParent.cpp
index a26f41107b5..8859957daa3 100755
--- a/dom/ipc/ContentParent.cpp
+++ b/dom/ipc/ContentParent.cpp
@@ -2641,16 +2641,18 @@ ContentParent::Observe(nsISupports* aSubject,
             MOZ_ASSERT(cmsg[identOffset - 1] == '=');
             FileDescriptor dmdFileDesc;
 #ifdef MOZ_DMD
-            FILE *dmdFile;
             nsAutoString dmdIdent(Substring(msg, identOffset));
-            nsresult rv = nsMemoryInfoDumper::OpenDMDFile(dmdIdent, Pid(), &dmdFile);
-            if (NS_WARN_IF(NS_FAILED(rv))) {
-                // Proceed with the memory report as if DMD were disabled.
-                dmdFile = nullptr;
-            }
-            if (dmdFile) {
-                dmdFileDesc = FILEToFileDescriptor(dmdFile);
-                fclose(dmdFile);
+            if (!dmdIdent.IsEmpty()) {
+                FILE *dmdFile = nullptr;
+                nsresult rv = nsMemoryInfoDumper::OpenDMDFile(dmdIdent, Pid(), &dmdFile);
+                if (NS_WARN_IF(NS_FAILED(rv))) {
+                    // Proceed with the memory report as if DMD were disabled.
+                    dmdFile = nullptr;
+                }
+                if (dmdFile) {
+                    dmdFileDesc = FILEToFileDescriptor(dmdFile);
+                    fclose(dmdFile);
+                }
             }
 #endif
             unused << SendPMemoryReportRequestConstructor(
diff --git a/xpcom/base/nsMemoryReporterManager.cpp b/xpcom/base/nsMemoryReporterManager.cpp
index 8d92b674b4f..215b33f0418 100644
--- a/xpcom/base/nsMemoryReporterManager.cpp
+++ b/xpcom/base/nsMemoryReporterManager.cpp
@@ -1189,11 +1189,13 @@ nsMemoryReporterManager::StartGettingReports()
   // Get reports for this process.
   FILE* parentDMDFile = nullptr;
 #ifdef MOZ_DMD
-  nsresult rv = nsMemoryInfoDumper::OpenDMDFile(s->mDMDDumpIdent, getpid(),
-                                                &parentDMDFile);
-  if (NS_WARN_IF(NS_FAILED(rv))) {
-    // Proceed with the memory report as if DMD were disabled.
-    parentDMDFile = nullptr;
+  if (!s->mDMDDumpIdent.IsEmpty()) {
+    nsresult rv = nsMemoryInfoDumper::OpenDMDFile(s->mDMDDumpIdent, getpid(),
+                                                  &parentDMDFile);
+    if (NS_WARN_IF(NS_FAILED(rv))) {
+      // Proceed with the memory report as if DMD were disabled.
+      parentDMDFile = nullptr;
+    }
   }
 #endif
   GetReportsForThisProcessExtended(s->mHandleReport, s->mHandleReportData,