Bug 1491909 - Add an AllocPolicy to mozilla::JSONWriter r=jwalden,mstange

JSONWriter currently calls new and delete indirectly through mozilla::MakeUnique to allocate a buffer.  Becuase of this, the methods of this class cannot be invoked within Spidermonkey due to https://searchfox.org/mozilla-central/source/config/check_vanilla_allocations.py#6-14.  Therefore, JSONWriter needs an AllocPolicy template parameter so that the allocation and deallocation routines can be changed to match the JS AllocPolicy when invoked within SpiderMonkey.

Differential Revision: https://phabricator.services.mozilla.com/D7279

--HG--
extra : moz-landing-system : lando

dom/base/ContentBlockingLog.h

@@ -85,7 +85,7 @@ public:
   {
     nsAutoString buffer;
 
-    JSONWriter w(MakeUnique<StringWriteFunc>(buffer));
+    JSONWriter<> w(MakeUnique<StringWriteFunc>(buffer));
     w.Start();
 
     for (auto iter = mLog.Iter(); !iter.Done(); iter.Next()) {

dom/media/doctor/DDLogValue.cpp

@@ -85,7 +85,7 @@ AppendToString(const DDLogValue& aValue, nsCString& aString)
 
 struct LogValueMatcherJson
 {
-  JSONWriter& mJW;
+  JSONWriter<>& mJW;
   const char* mPropertyName;
 
   void match(const DDNoValue&) const { mJW.NullProperty(mPropertyName); }
@@ -137,7 +137,7 @@ struct LogValueMatcherJson
 
 void
 ToJSON(const DDLogValue& aValue,
-       JSONWriter& aJSONWriter,
+       JSONWriter<>& aJSONWriter,
        const char* aPropertyName)
 {
   aValue.match(LogValueMatcherJson{ aJSONWriter, aPropertyName });

dom/media/doctor/DDLogValue.h

@@ -54,10 +54,12 @@ using DDLogValue = Variant<DDNoValue,
 void
 AppendToString(const DDLogValue& aValue, nsCString& aString);
 
+template <class AllocPolicy>
 class JSONWriter;
+class MallocAllocPolicy;
 void
 ToJSON(const DDLogValue& aValue,
-       JSONWriter& aJSONWriter,
+       JSONWriter<MallocAllocPolicy>& aJSONWriter,
        const char* aPropertyName);
 
 } // namespace mozilla

dom/media/doctor/DDMediaLogs.cpp

@@ -462,11 +462,11 @@ DDMediaLogs::FulfillPromises()
     }
 
     nsCString json;
-    JSONWriter jw{ MakeUnique<StringWriteFunc>(json) };
+    JSONWriter<> jw{ MakeUnique<StringWriteFunc>(json) };
     jw.Start();
     jw.StartArrayProperty("messages");
     for (const DDLogMessage& message : log->mMessages) {
-      jw.StartObjectElement(JSONWriter::SingleLineStyle);
+      jw.StartObjectElement(JSONWriter<>::SingleLineStyle);
       jw.IntProperty("i", message.mIndex.Value());
       jw.DoubleProperty("ts", ToSeconds(message.mTimeStamp));
       DDLifetime* lifetime =
@@ -505,7 +505,7 @@ DDMediaLogs::FulfillPromises()
       mediaElement,
       [&](const DDLifetime& lifetime) {
         jw.StartObjectProperty(nsPrintfCString("%" PRIi32, lifetime.mTag).get(),
-                               JSONWriter::SingleLineStyle);
+                               JSONWriter<>::SingleLineStyle);
         jw.IntProperty("tag", lifetime.mTag);
         jw.StringProperty("cls", lifetime.mObject.TypeName());
         jw.StringProperty(

dom/notification/Notification.cpp

@@ -1742,7 +1742,7 @@ Notification::ShowInternal()
   if (isPersistent) {
     nsAutoString persistentData;
 
-    JSONWriter w(MakeUnique<StringWriteFunc>(persistentData));
+    JSONWriter<> w(MakeUnique<StringWriteFunc>(persistentData));
     w.Start();
 
     nsAutoString origin;

ipc/mscom/RegistrationAnnotator.cpp

@@ -141,9 +141,9 @@ GetLoadedPath(nsAString& aPath)
 }
 
 static void
-AnnotateClsidRegistrationForHive(JSONWriter& aJson, HKEY aHive,
+AnnotateClsidRegistrationForHive(JSONWriter<>& aJson, HKEY aHive,
                                  const nsAString& aClsid,
-                                 const JSONWriter::CollectionStyle aStyle)
+                                 const JSONWriter<>::CollectionStyle aStyle)
 {
   nsAutoString clsidSubkey;
   clsidSubkey.AppendLiteral(kSoftwareClasses);
@@ -193,7 +193,7 @@ AnnotateClsidRegistrationForHive(JSONWriter& aJson, HKEY aHive,
 }
 
 static void
-CheckTlbPath(JSONWriter& aJson, const nsAString& aTypelibPath)
+CheckTlbPath(JSONWriter<>& aJson, const nsAString& aTypelibPath)
 {
   const nsString& flatPath = PromiseFlatString(aTypelibPath);
   DWORD bufCharLen = ExpandEnvironmentStrings(flatPath.get(), nullptr, 0);
@@ -214,10 +214,10 @@ CheckTlbPath(JSONWriter& aJson, const nsAString& aTypelibPath)
 
 template <size_t N>
 static void
-AnnotateTypelibPlatform(JSONWriter& aJson, HKEY aBaseKey,
+AnnotateTypelibPlatform(JSONWriter<>& aJson, HKEY aBaseKey,
                         const nsAString& aLcidSubkey,
                         const char16_t (&aPlatform)[N],
-                        const JSONWriter::CollectionStyle aStyle)
+                        const JSONWriter<>::CollectionStyle aStyle)
 {
   nsLiteralString platform(aPlatform);
 
@@ -235,10 +235,10 @@ AnnotateTypelibPlatform(JSONWriter& aJson, HKEY aBaseKey,
 }
 
 static void
-AnnotateTypelibRegistrationForHive(JSONWriter& aJson, HKEY aHive,
+AnnotateTypelibRegistrationForHive(JSONWriter<>& aJson, HKEY aHive,
                                    const nsAString& aTypelibId,
                                    const nsAString& aTypelibVersion,
-                                   const JSONWriter::CollectionStyle aStyle)
+                                   const JSONWriter<>::CollectionStyle aStyle)
 {
   nsAutoString typelibSubKey;
   typelibSubKey.AppendLiteral(kSoftwareClasses);
@@ -293,8 +293,8 @@ AnnotateTypelibRegistrationForHive(JSONWriter& aJson, HKEY aHive,
 }
 
 static void
-AnnotateInterfaceRegistrationForHive(JSONWriter& aJson, HKEY aHive, REFIID aIid,
-                                     const JSONWriter::CollectionStyle aStyle)
+AnnotateInterfaceRegistrationForHive(JSONWriter<>& aJson, HKEY aHive, REFIID aIid,
+                                     const JSONWriter<>::CollectionStyle aStyle)
 {
   nsAutoString interfaceSubKey;
   interfaceSubKey.AppendLiteral(kSoftwareClasses);
@@ -357,12 +357,12 @@ void
 AnnotateInterfaceRegistration(REFIID aIid)
 {
 #if defined(DEBUG)
-  const JSONWriter::CollectionStyle style = JSONWriter::MultiLineStyle;
+  const JSONWriter<>::CollectionStyle style = JSONWriter<>::MultiLineStyle;
 #else
-  const JSONWriter::CollectionStyle style = JSONWriter::SingleLineStyle;
+  const JSONWriter<>::CollectionStyle style = JSONWriter<>::SingleLineStyle;
 #endif
 
-  JSONWriter json(MakeUnique<CStringWriter>());
+  JSONWriter<> json(MakeUnique<CStringWriter>());
 
   json.Start(style);
 
@@ -391,15 +391,15 @@ void
 AnnotateClassRegistration(REFCLSID aClsid)
 {
 #if defined(DEBUG)
-  const JSONWriter::CollectionStyle style = JSONWriter::MultiLineStyle;
+  const JSONWriter<>::CollectionStyle style = JSONWriter<>::MultiLineStyle;
 #else
-  const JSONWriter::CollectionStyle style = JSONWriter::SingleLineStyle;
+  const JSONWriter<>::CollectionStyle style = JSONWriter<>::SingleLineStyle;
 #endif
 
   nsAutoString strClsid;
   GUIDToString(aClsid, strClsid);
 
-  JSONWriter json(MakeUnique<CStringWriter>());
+  JSONWriter<> json(MakeUnique<CStringWriter>());
 
   json.Start(style);
 

js/public/AllocPolicy.h

@@ -134,4 +134,8 @@ class TempAllocPolicy : public AllocPolicyBase
 
 } /* namespace js */
 
+namespace JS {
+using SystemAllocPolicy = js::SystemAllocPolicy;
+} /* namespace JS */
+
 #endif /* js_AllocPolicy_h */

memory/replace/dmd/DMD.cpp

@@ -1789,7 +1789,7 @@ private:
 };
 
 static void
-WriteBlockContents(JSONWriter& aWriter, const LiveBlock& aBlock)
+WriteBlockContents(JSONWriter<>& aWriter, const LiveBlock& aBlock)
 {
   size_t numWords = aBlock.ReqSize() / sizeof(uintptr_t*);
   if (numWords == 0) {
@@ -1817,7 +1817,7 @@ AnalyzeImpl(UniquePtr<JSONWriteFunc> aWriter)
   // Therefore, this declaration must precede the AutoBlockIntercepts
   // declaration, to ensure that |write| is destroyed *after* intercepts are
   // unblocked.
-  JSONWriter writer(std::move(aWriter));
+  JSONWriter<> writer(std::move(aWriter));
 
   AutoBlockIntercepts block(Thread::Fetch());
   AutoLockState lock;

mfbt/JSONWriter.h

@@ -120,6 +120,7 @@ namespace detail {
 extern MFBT_DATA const char gTwoCharEscapes[256];
 } // namespace detail
 
+template <class AllocPolicy = MallocAllocPolicy>
 class JSONWriter
 {
   // From http://www.ietf.org/rfc/rfc4627.txt:
@@ -142,7 +143,15 @@ class JSONWriter
     // wouldn't work with UniquePtr.
     bool mIsOwned;
     const char* mUnownedStr;
-    UniquePtr<char[]> mOwnedStr;
+
+    struct FreePolicy {
+      AllocPolicy mAllocPolicy;
+      void operator() (void* p) {
+        mAllocPolicy.free_(p);
+      }
+    };
+
+    UniquePtr<char[], FreePolicy> mOwnedStr;
 
     void SanityCheck() const
     {
@@ -156,6 +165,10 @@ class JSONWriter
       return u < 10 ? '0' + u : 'a' + (u - 10);
     }
 
+    AllocPolicy& allocPolicy() {
+      return mOwnedStr.get_deleter().mAllocPolicy;
+    }
+
   public:
     explicit EscapedString(const char* aStr)
       : mUnownedStr(nullptr)
@@ -189,7 +202,8 @@ class JSONWriter
       // Escapes are needed. We'll create a new string.
       mIsOwned = true;
       size_t len = (p - aStr) + nExtra;
-      mOwnedStr = MakeUnique<char[]>(len + 1);
+      UniquePtr<char[], FreePolicy> buffer(allocPolicy().template pod_malloc<char>(len + 1));
+      mOwnedStr = std::move(buffer);
 
       p = aStr;
       size_t i = 0;

mfbt/tests/TestJSONWriter.cpp

@@ -101,7 +101,7 @@ void TestBasicProperties()
 }\n\
 ";
 
-  JSONWriter w(MakeUnique<StringWriteFunc>());
+  JSONWriter<> w(MakeUnique<StringWriteFunc>());
 
   w.Start();
   {
@@ -260,7 +260,7 @@ void TestBasicElements()
 }\n\
 ";
 
-  JSONWriter w(MakeUnique<StringWriteFunc>());
+  JSONWriter<> w(MakeUnique<StringWriteFunc>());
 
   w.Start();
   w.StartArrayProperty("array");
@@ -376,7 +376,7 @@ void TestOneLineObject()
 {\"i\": 1, \"array\": [null, [{}], {\"o\": {}}, \"s\"], \"d\": 3.33}\n\
 ";
 
-  JSONWriter w(MakeUnique<StringWriteFunc>());
+  JSONWriter<> w(MakeUnique<StringWriteFunc>());
 
   w.Start(w.SingleLineStyle);
 
@@ -430,7 +430,7 @@ void TestStringEscaping()
 }\n\
 ";
 
-  JSONWriter w(MakeUnique<StringWriteFunc>());
+  JSONWriter<> w(MakeUnique<StringWriteFunc>());
 
   // Test the string escaping behaviour.
   w.Start();
@@ -508,7 +508,7 @@ void TestDeepNesting()
 }\n\
 ";
 
-  JSONWriter w(MakeUnique<StringWriteFunc>());
+  JSONWriter<> w(MakeUnique<StringWriteFunc>());
 
   w.Start();
   {
@@ -533,7 +533,7 @@ void TestEscapedPropertyNames()
 {\"i\\t\": 1, \"array\\t\": [null, [{}], {\"o\\t\": {}}, \"s\"], \"d\\t\": 3.33}\n\
 ";
 
-  JSONWriter w(MakeUnique<StringWriteFunc>());
+  JSONWriter<> w(MakeUnique<StringWriteFunc>());
 
   w.Start(w.SingleLineStyle);
 

toolkit/components/places/Database.cpp

@@ -2584,8 +2584,8 @@ Database::MigrateV51Up()
   NS_ENSURE_SUCCESS(rv, rv);
 
   nsAutoCString json;
-  JSONWriter jw{ MakeUnique<StringWriteFunc>(json) };
-  jw.StartArrayProperty(nullptr, JSONWriter::SingleLineStyle);
+  JSONWriter<> jw{ MakeUnique<StringWriteFunc>(json) };
+  jw.StartArrayProperty(nullptr, JSONWriter<>::SingleLineStyle);
 
   bool hasAtLeastOne = false;
   bool hasMore = false;

toolkit/components/telemetry/core/TelemetryHistogram.cpp

@@ -2638,7 +2638,7 @@ namespace {
  */
 void
 internal_ReflectHistogramToJSON(const HistogramSnapshotData& aSnapshot,
-                                mozilla::JSONWriter& aWriter)
+                                mozilla::JSONWriter<>& aWriter)
 {
   aWriter.IntProperty("sum", aSnapshot.mSampleSum);
 
@@ -2765,7 +2765,7 @@ internal_ParseHistogramData(JSContext* aCx, JS::HandleId aEntryId,
 // PUBLIC: GeckoView serialization/deserialization functions.
 
 nsresult
-TelemetryHistogram::SerializeHistograms(mozilla::JSONWriter& aWriter)
+TelemetryHistogram::SerializeHistograms(mozilla::JSONWriter<>& aWriter)
 {
   MOZ_ASSERT(XRE_IsParentProcess(), "Only save histograms in the parent process");
   if (!XRE_IsParentProcess()) {
@@ -2812,7 +2812,7 @@ TelemetryHistogram::SerializeHistograms(mozilla::JSONWriter& aWriter)
 }
 
 nsresult
-TelemetryHistogram::SerializeKeyedHistograms(mozilla::JSONWriter& aWriter)
+TelemetryHistogram::SerializeKeyedHistograms(mozilla::JSONWriter<>& aWriter)
 {
   MOZ_ASSERT(XRE_IsParentProcess(), "Only save keyed histograms in the parent process");
   if (!XRE_IsParentProcess()) {

toolkit/components/telemetry/core/TelemetryHistogram.h

@@ -13,9 +13,10 @@
 
 namespace mozilla{
 // This is only used for the GeckoView persistence.
+template <class AllocPolicy>
 class JSONWriter;
+class MallocAllocPolicy;
 }
-
 // This module is internal to Telemetry.  It encapsulates Telemetry's
 // histogram accumulation and storage logic.  It should only be used by
 // Telemetry.cpp.  These functions should not be used anywhere else.
@@ -81,8 +82,8 @@ GetHistogramSizesOfIncludingThis(mozilla::MallocSizeOf aMallocSizeOf);
 // These functions are only meant to be used for GeckoView persistence.
 // They are responsible for updating in-memory probes with the data persisted
 // on the disk and vice-versa.
-nsresult SerializeHistograms(mozilla::JSONWriter &aWriter);
-nsresult SerializeKeyedHistograms(mozilla::JSONWriter &aWriter);
+nsresult SerializeHistograms(mozilla::JSONWriter<mozilla::MallocAllocPolicy>& aWriter);
+nsresult SerializeKeyedHistograms(mozilla::JSONWriter<mozilla::MallocAllocPolicy>& aWriter);
 nsresult DeserializeHistograms(JSContext* aCx, JS::HandleValue aData);
 nsresult DeserializeKeyedHistograms(JSContext* aCx, JS::HandleValue aData);
 

toolkit/components/telemetry/core/TelemetryScalar.cpp

@@ -272,7 +272,7 @@ GetVariantFromIVariant(nsIVariant* aInput, uint32_t aScalarKind,
  */
 nsresult
 WriteVariantToJSONWriter(uint32_t aScalarType, nsIVariant* aInputValue,
-                         const char* aPropertyName, mozilla::JSONWriter& aWriter)
+                         const char* aPropertyName, mozilla::JSONWriter<>& aWriter)
 {
   MOZ_ASSERT(aInputValue);
 
@@ -3480,7 +3480,7 @@ TelemetryScalar::AddDynamicScalarDefinitions(
  * @returns NS_OK or a failure value explaining why persistence failed.
  */
 nsresult
-TelemetryScalar::SerializeScalars(mozilla::JSONWriter& aWriter)
+TelemetryScalar::SerializeScalars(mozilla::JSONWriter<>& aWriter)
 {
   // Get a copy of the data, without clearing.
   ScalarSnapshotTable scalarsToReflect;
@@ -3531,7 +3531,7 @@ TelemetryScalar::SerializeScalars(mozilla::JSONWriter& aWriter)
  * @returns NS_OK or a failure value explaining why persistence failed.
  */
 nsresult
-TelemetryScalar::SerializeKeyedScalars(mozilla::JSONWriter& aWriter)
+TelemetryScalar::SerializeKeyedScalars(mozilla::JSONWriter<>& aWriter)
 {
   // Get a copy of the data, without clearing.
   KeyedScalarSnapshotTable keyedScalarsToReflect;

toolkit/components/telemetry/core/TelemetryScalar.h

@@ -18,7 +18,9 @@
 
 namespace mozilla {
 // This is only used for the GeckoView persistence.
+template <class AllocPolicy>
 class JSONWriter;
+class MallocAllocPolicy;
 namespace Telemetry {
   struct ScalarAction;
   struct KeyedScalarAction;
@@ -94,8 +96,8 @@ void AddDynamicScalarDefinitions(const nsTArray<mozilla::Telemetry::DynamicScala
 
 // They are responsible for updating in-memory probes with the data persisted
 // on the disk and vice-versa.
-nsresult SerializeScalars(mozilla::JSONWriter &aWriter);
-nsresult SerializeKeyedScalars(mozilla::JSONWriter &aWriter);
+nsresult SerializeScalars(mozilla::JSONWriter<mozilla::MallocAllocPolicy>& aWriter);
+nsresult SerializeKeyedScalars(mozilla::JSONWriter<mozilla::MallocAllocPolicy>& aWriter);
 nsresult DeserializePersistedScalars(JSContext* aCx, JS::HandleValue aData);
 nsresult DeserializePersistedKeyedScalars(JSContext* aCx, JS::HandleValue aData);
 // Mark deserialization as in progress.

toolkit/components/telemetry/geckoview/TelemetryGeckoViewPersistence.cpp

@@ -382,7 +382,7 @@ PersistenceThreadPersist()
   }
 
   // Build the JSON structure: give up the ownership of jsonWriter.
-  mozilla::JSONWriter w(std::move(jsonWriter));
+  mozilla::JSONWriter<> w(std::move(jsonWriter));
   w.Start();
 
   w.StartObjectProperty("scalars");

tools/profiler/core/ProfileBufferEntry.cpp

@@ -85,11 +85,11 @@ ProfileBufferEntry::ProfileBufferEntry(Kind aKind, uint64_t aUint64)
 
 class JSONSchemaWriter
 {
-  JSONWriter& mWriter;
+  ProfilerJSONWriter& mWriter;
   uint32_t mIndex;
 
 public:
-  explicit JSONSchemaWriter(JSONWriter& aWriter)
+  explicit JSONSchemaWriter(ProfilerJSONWriter& aWriter)
    : mWriter(aWriter)
    , mIndex(0)
   {

tools/profiler/core/ProfileBufferEntry.h

@@ -140,11 +140,11 @@ public:
     aWriter.TakeAndSplice(mStringTableWriter.WriteFunc());
   }
 
-  void WriteProperty(mozilla::JSONWriter& aWriter, const char* aName, const char* aStr) {
+  void WriteProperty(ProfilerJSONWriter& aWriter, const char* aName, const char* aStr) {
     aWriter.IntProperty(aName, GetOrAddIndex(aStr));
   }
 
-  void WriteElement(mozilla::JSONWriter& aWriter, const char* aStr) {
+  void WriteElement(ProfilerJSONWriter& aWriter, const char* aStr) {
     aWriter.IntElement(GetOrAddIndex(aStr));
   }
 

tools/profiler/core/platform.cpp

@@ -1567,7 +1567,7 @@ SafeJSInteger(uint64_t aValue) {
 }
 
 static void
-AddSharedLibraryInfoToStream(JSONWriter& aWriter, const SharedLibrary& aLib)
+AddSharedLibraryInfoToStream(ProfilerJSONWriter& aWriter, const SharedLibrary& aLib)
 {
   aWriter.StartObjectElement();
   aWriter.IntProperty("start", SafeJSInteger(aLib.GetStart()));
@@ -1583,7 +1583,7 @@ AddSharedLibraryInfoToStream(JSONWriter& aWriter, const SharedLibrary& aLib)
 }
 
 void
-AppendSharedLibraries(JSONWriter& aWriter)
+AppendSharedLibraries(ProfilerJSONWriter& aWriter)
 {
   SharedLibraryInfo info = SharedLibraryInfo::GetInfoForSelf();
   info.SortByAddress();
@@ -1594,7 +1594,7 @@ AppendSharedLibraries(JSONWriter& aWriter)
 
 #ifdef MOZ_TASK_TRACER
 static void
-StreamNameAndThreadId(JSONWriter& aWriter, const char* aName, int aThreadId)
+StreamNameAndThreadId(ProfilerJSONWriter& aWriter, const char* aName, int aThreadId)
 {
   aWriter.StartObjectElement();
   {
@@ -1823,7 +1823,7 @@ StreamMetaJSCustomObject(PSLockRef aLock, SpliceableJSONWriter& aWriter,
         ExtensionPolicyService::GetSingleton().GetAll(exts);
 
         for (auto& ext : exts) {
-          aWriter.StartArrayElement(JSONWriter::SingleLineStyle);
+          aWriter.StartArrayElement(ProfilerJSONWriter::SingleLineStyle);
 
           nsAutoString id;
           ext->GetId(id);

tools/profiler/core/platform.h

@@ -40,6 +40,7 @@
 #include "mozilla/UniquePtr.h"
 #include "mozilla/Unused.h"
 #include "PlatformMacros.h"
+#include "ProfileJSONWriter.h"
 #include <vector>
 
 // We need a definition of gettid(), but glibc doesn't provide a
@@ -116,9 +117,11 @@ typedef mozilla::UniquePtr<PlatformData, PlatformDataDestructor>
 UniquePlatformData AllocPlatformData(int aThreadId);
 
 namespace mozilla {
+template <class AllocPolicy>
 class JSONWriter;
+class MallocAllocPolicy;
 }
-void AppendSharedLibraries(mozilla::JSONWriter& aWriter);
+void AppendSharedLibraries(ProfilerJSONWriter& aWriter);
 
 // Convert the array of strings to a bitfield.
 uint32_t ParseFeaturesFromStringArray(const char** aFeatures,

tools/profiler/gecko/nsProfiler.cpp

@@ -193,7 +193,7 @@ nsProfiler::GetSharedLibraries(JSContext* aCx,
   JS::RootedValue val(aCx);
   {
     nsString buffer;
-    JSONWriter w(MakeUnique<StringWriteFunc>(buffer));
+    ProfilerJSONWriter w(MakeUnique<StringWriteFunc>(buffer));
     w.StartArrayElement();
     AppendSharedLibraries(w);
     w.EndArray();

tools/profiler/public/ProfileJSONWriter.h

@@ -10,9 +10,14 @@
 #include <string>
 #include <string.h>
 
+#include "js/AllocPolicy.h"
 #include "mozilla/JSONWriter.h"
 #include "mozilla/UniquePtr.h"
 
+// JS::SystemAllocPolicy is used here instead of the default so that the JSONWriter
+// object can also be passed into SpiderMonkey and used there.
+using ProfilerJSONWriter = mozilla::JSONWriter<JS::SystemAllocPolicy>;
+
 class SpliceableChunkedJSONWriter;
 
 // On average, profile JSONs are large enough such that we want to avoid
@@ -83,11 +88,11 @@ struct OStreamJSONWriteFunc : public mozilla::JSONWriteFunc
   std::ostream& mStream;
 };
 
-class SpliceableJSONWriter : public mozilla::JSONWriter
+class SpliceableJSONWriter : public ProfilerJSONWriter
 {
 public:
   explicit SpliceableJSONWriter(mozilla::UniquePtr<mozilla::JSONWriteFunc> aWriter)
-    : JSONWriter(std::move(aWriter))
+    : ProfilerJSONWriter(std::move(aWriter))
   { }
 
   void StartBareList(CollectionStyle aStyle = MultiLineStyle) {

xpcom/base/nsMacPreferencesReader.mm

@@ -25,10 +25,10 @@ struct StringWriteFunc : public JSONWriteFunc
 };
 
 static void
-EvaluateDict(JSONWriter* aWriter, NSDictionary<NSString*, id>* aDict);
+EvaluateDict(JSONWriter<>* aWriter, NSDictionary<NSString*, id>* aDict);
 
 static void
-EvaluateArray(JSONWriter* aWriter, NSArray* aArray)
+EvaluateArray(JSONWriter<>* aWriter, NSArray* aArray)
 {
   for (id elem in aArray) {
     if ([elem isKindOfClass:[NSString class]]) {
@@ -48,7 +48,7 @@ EvaluateArray(JSONWriter* aWriter, NSArray* aArray)
 }
 
 static void
-EvaluateDict(JSONWriter* aWriter, NSDictionary<NSString*, id>* aDict)
+EvaluateDict(JSONWriter<>* aWriter, NSDictionary<NSString*, id>* aDict)
 {
   for (NSString* key in aDict) {
     id value = aDict[key];
@@ -83,7 +83,7 @@ nsMacPreferencesReader::ReadPreferences(JSContext* aCx,
                                         JS::MutableHandle<JS::Value> aResult)
 {
   nsAutoString jsonStr;
-  JSONWriter w(MakeUnique<StringWriteFunc>(jsonStr));
+  JSONWriter<> w(MakeUnique<StringWriteFunc>(jsonStr));
   w.Start();
   EvaluateDict(&w, [[NSUserDefaults standardUserDefaults]
                      dictionaryRepresentation]);

xpcom/base/nsMemoryInfoDumper.cpp

@@ -469,7 +469,7 @@ class HandleReportAndFinishReportingCallbacks final
 public:
   NS_DECL_ISUPPORTS
 
-  HandleReportAndFinishReportingCallbacks(UniquePtr<JSONWriter> aWriter,
+  HandleReportAndFinishReportingCallbacks(UniquePtr<JSONWriter<>> aWriter,
                                           nsIFinishDumpingCallback* aFinishDumping,
                                           nsISupports* aFinishDumpingData)
     : mWriter(std::move(aWriter))
@@ -545,7 +545,7 @@ public:
 private:
   ~HandleReportAndFinishReportingCallbacks() {}
 
-  UniquePtr<JSONWriter> mWriter;
+  UniquePtr<JSONWriter<>> mWriter;
   nsCOMPtr<nsIFinishDumpingCallback> mFinishDumping;
   nsCOMPtr<nsISupports> mFinishDumpingData;
 };
@@ -649,7 +649,7 @@ DumpMemoryInfoToFile(
     return rv;
   }
   auto jsonWriter =
-    MakeUnique<JSONWriter>(MakeUnique<GZWriterWrapper>(gzWriter));
+    MakeUnique<JSONWriter<>>(MakeUnique<GZWriterWrapper>(gzWriter));
 
   nsCOMPtr<nsIMemoryReporterManager> mgr =
     do_GetService("@mozilla.org/memory-reporter-manager;1");