Bug 1556358 - Allow FormData::ForEach to take a closure instead of a raw function pointer. r=edgar

Depends on D174114

Differential Revision: https://phabricator.services.mozilla.com/D175542

dom/base/FormData.h

@@ -127,18 +127,17 @@ class FormData final : public nsISupports,
   virtual nsresult AddNameDirectoryPair(const nsAString& aName,
                                         Directory* aDirectory) override;
 
-  using FormDataEntryCallback =
-      bool (*)(const nsString& aName,
-               const OwningBlobOrDirectoryOrUSVString& aValue, void* aClosure);
-
   uint32_t Length() const { return mFormData.Length(); }
 
   // Stops iteration and returns false if any invocation of callback returns
   // false. Returns true otherwise.
-  bool ForEach(FormDataEntryCallback aFunc, void* aClosure) {
+  // Accepts callbacks of the form `bool(const nsString&, const
+  // OwningBlobOrDirectoryOrUSVString&)`.
+  template <typename F>
+  bool ForEach(F&& aCallback) {
     for (uint32_t i = 0; i < mFormData.Length(); ++i) {
       FormDataTuple& tuple = mFormData[i];
-      if (!aFunc(tuple.name, tuple.value, aClosure)) {
+      if (!aCallback(tuple.name, tuple.value)) {
         return false;
       }
     }

dom/base/StructuredCloneHolder.cpp

@@ -896,52 +896,36 @@ bool WriteFormData(JSStructuredCloneWriter* aWriter, FormData* aFormData,
     return false;
   }
 
-  class MOZ_STACK_CLASS Closure final {
-    JSStructuredCloneWriter* mWriter;
-    StructuredCloneHolder* mHolder;
+  auto write = [aWriter, aHolder](
+                   const nsString& aName,
+                   const OwningBlobOrDirectoryOrUSVString& aValue) {
+    if (!StructuredCloneHolder::WriteString(aWriter, aName)) {
+      return false;
+    }
 
-   public:
-    Closure(JSStructuredCloneWriter* aWriter, StructuredCloneHolder* aHolder)
-        : mWriter(aWriter), mHolder(aHolder) {}
-
-    static bool Write(const nsString& aName,
-                      const OwningBlobOrDirectoryOrUSVString& aValue,
-                      void* aClosure) {
-      Closure* closure = static_cast<Closure*>(aClosure);
-      if (!StructuredCloneHolder::WriteString(closure->mWriter, aName)) {
+    if (aValue.IsBlob()) {
+      if (!JS_WriteUint32Pair(aWriter, SCTAG_DOM_BLOB,
+                              aHolder->BlobImpls().Length())) {
         return false;
       }
 
-      if (aValue.IsBlob()) {
-        if (!JS_WriteUint32Pair(closure->mWriter, SCTAG_DOM_BLOB,
-                                closure->mHolder->BlobImpls().Length())) {
-          return false;
-        }
-
-        RefPtr<BlobImpl> blobImpl = aValue.GetAsBlob()->Impl();
-
-        closure->mHolder->BlobImpls().AppendElement(blobImpl);
-        return true;
-      }
-
-      if (aValue.IsDirectory()) {
-        Directory* directory = aValue.GetAsDirectory();
-        return WriteDirectory(closure->mWriter, directory);
-      }
-
-      size_t charSize = sizeof(nsString::char_type);
-      if (!JS_WriteUint32Pair(closure->mWriter, 0,
-                              aValue.GetAsUSVString().Length()) ||
-          !JS_WriteBytes(closure->mWriter, aValue.GetAsUSVString().get(),
-                         aValue.GetAsUSVString().Length() * charSize)) {
-        return false;
-      }
+      RefPtr<BlobImpl> blobImpl = aValue.GetAsBlob()->Impl();
 
+      aHolder->BlobImpls().AppendElement(blobImpl);
       return true;
     }
+
+    if (aValue.IsDirectory()) {
+      Directory* directory = aValue.GetAsDirectory();
+      return WriteDirectory(aWriter, directory);
+    }
+
+    const size_t charSize = sizeof(nsString::char_type);
+    return JS_WriteUint32Pair(aWriter, 0, aValue.GetAsUSVString().Length()) &&
+           JS_WriteBytes(aWriter, aValue.GetAsUSVString().get(),
+                         aValue.GetAsUSVString().Length() * charSize);
   };
-  Closure closure(aWriter, aHolder);
-  return aFormData->ForEach(Closure::Write, &closure);
+  return aFormData->ForEach(write);
 }
 
 JSObject* ReadWasmModule(JSContext* aCx, uint32_t aIndex,