From 61bffae5df9b3e22f1762e1e51eab8967599b7c2 Mon Sep 17 00:00:00 2001
From: Jan Varga <jvarga@mozilla.com>
Date: Wed, 9 Oct 2024 22:16:49 +0000
Subject: [PATCH] Bug 1866402 - QM: Generalize the helper for mapping
 MozPromise values to support both exclusive and non-exclusive promises;
 r=dom-storage-reviewers,jari

Differential Revision: https://phabricator.services.mozilla.com/D223276
---
 dom/quota/MozPromiseUtils.h                  | 41 +++++++++++++++++++-
 dom/quota/test/gtest/TestMozPromiseUtils.cpp | 10 +++++
 2 files changed, 50 insertions(+), 1 deletion(-)

diff --git a/dom/quota/MozPromiseUtils.h b/dom/quota/MozPromiseUtils.h
index 3e7b5f70f109..0b91a9e8966f 100644
--- a/dom/quota/MozPromiseUtils.h
+++ b/dom/quota/MozPromiseUtils.h
@@ -8,11 +8,31 @@
 #define DOM_QUOTA_MOZPROMISEUTILS_H_
 
 #include "mozilla/MozPromise.h"
+#include "nsThreadUtils.h"
 
 namespace mozilla::dom::quota {
 
+namespace detail {
+
+template <typename T>
+struct IsExclusiveMozPromise {
+  static constexpr bool value = false;
+};
+
+// Specialization for MozPromise
+template <typename ResolveValueT, typename RejectValueT, bool IsExclusive>
+struct IsExclusiveMozPromise<
+    MozPromise<ResolveValueT, RejectValueT, IsExclusive>> {
+  static constexpr bool value = IsExclusive;
+};
+
+}  // namespace detail
+
 template <typename T, typename U, typename F>
-RefPtr<T> Map(RefPtr<U> aPromise, F&& aFunc) {
+auto Map(RefPtr<U> aPromise, F&& aFunc)
+    -> std::enable_if_t<
+        detail::IsExclusiveMozPromise<RemoveSmartPointer<U>>::value,
+        RefPtr<T>> {
   return aPromise->Then(
       GetCurrentSerialEventTarget(), __func__,
       [func =
@@ -27,6 +47,25 @@ RefPtr<T> Map(RefPtr<U> aPromise, F&& aFunc) {
       });
 }
 
+template <typename T, typename U, typename F>
+auto Map(RefPtr<U> aPromise, F&& aFunc)
+    -> std::enable_if_t<
+        !detail::IsExclusiveMozPromise<RemoveSmartPointer<U>>::value,
+        RefPtr<T>> {
+  return aPromise->Then(GetCurrentSerialEventTarget(), __func__,
+                        [func = std::forward<F>(aFunc)](
+                            const typename U::ResolveOrRejectValue& aValue) {
+                          if (aValue.IsReject()) {
+                            return T::CreateAndReject(aValue.RejectValue(),
+                                                      __func__);
+                          }
+
+                          auto value = func(aValue);
+
+                          return T::CreateAndResolve(value, __func__);
+                        });
+}
+
 }  // namespace mozilla::dom::quota
 
 #endif  // DOM_QUOTA_MOZPROMISEUTILS_H_
diff --git a/dom/quota/test/gtest/TestMozPromiseUtils.cpp b/dom/quota/test/gtest/TestMozPromiseUtils.cpp
index 343d389658e5..b95dfcc0b3de 100644
--- a/dom/quota/test/gtest/TestMozPromiseUtils.cpp
+++ b/dom/quota/test/gtest/TestMozPromiseUtils.cpp
@@ -9,6 +9,16 @@
 
 namespace mozilla::dom::quota::test {
 
+TEST(DOM_Quota_MozPromiseUtils, BoolPromiseToBoolPromise)
+{
+  auto value = QuotaManagerDependencyFixture::Await(Map<BoolPromise>(
+      BoolPromise::CreateAndResolve(true, __func__),
+      [](const BoolPromise::ResolveOrRejectValue& aValue) { return false; }));
+
+  ASSERT_TRUE(value.IsResolve());
+  ASSERT_FALSE(value.ResolveValue());
+}
+
 TEST(DOM_Quota_MozPromiseUtils, ExclusiveBoolPromiseToBoolPromise)
 {
   auto value = QuotaManagerDependencyFixture::Await(