1 files changed, 109 insertions, 0 deletions
diff --git a/dom/html/FetchPriority.cpp b/dom/html/FetchPriority.cpp
new file mode 100644
index 0000000000..259c05c6c3
--- /dev/null
+++ b/dom/html/FetchPriority.cpp
@@ -0,0 +1,109 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "mozilla/dom/FetchPriority.h"
+
+#include "mozilla/Assertions.h"
+#include "mozilla/Logging.h"
+#include "mozilla/dom/RequestBinding.h"
+#include "nsISupportsPriority.h"
+#include "nsStringFwd.h"
+
+namespace mozilla::dom {
+const char* kFetchPriorityAttributeValueHigh = "high";
+const char* kFetchPriorityAttributeValueLow = "low";
+const char* kFetchPriorityAttributeValueAuto = "auto";
+
+FetchPriority ToFetchPriority(RequestPriority aRequestPriority) {
+  switch (aRequestPriority) {
+    case RequestPriority::High: {
+      return FetchPriority::High;
+    }
+    case RequestPriority::Low: {
+      return FetchPriority::Low;
+    }
+    case RequestPriority::Auto: {
+      return FetchPriority::Auto;
+    }
+    default: {
+      MOZ_ASSERT_UNREACHABLE();
+      return FetchPriority::Auto;
+    }
+  }
+}
+
+#ifdef DEBUG
+constexpr auto kPriorityHighest = "PRIORITY_HIGHEST"_ns;
+constexpr auto kPriorityHigh = "PRIORITY_HIGH"_ns;
+constexpr auto kPriorityNormal = "PRIORITY_NORMAL"_ns;
+constexpr auto kPriorityLow = "PRIORITY_LOW"_ns;
+constexpr auto kPriorityLowest = "PRIORITY_LOWEST"_ns;
+constexpr auto kPriorityUnknown = "UNKNOWN"_ns;
+
+/**
+ * See <nsISupportsPriority.idl>.
+ */
+static void SupportsPriorityToString(int32_t aSupportsPriority,
+                                     nsACString& aResult) {
+  switch (aSupportsPriority) {
+    case nsISupportsPriority::PRIORITY_HIGHEST: {
+      aResult = kPriorityHighest;
+      break;
+    }
+    case nsISupportsPriority::PRIORITY_HIGH: {
+      aResult = kPriorityHigh;
+      break;
+    }
+    case nsISupportsPriority::PRIORITY_NORMAL: {
+      aResult = kPriorityNormal;
+      break;
+    }
+    case nsISupportsPriority::PRIORITY_LOW: {
+      aResult = kPriorityLow;
+      break;
+    }
+    case nsISupportsPriority::PRIORITY_LOWEST: {
+      aResult = kPriorityLowest;
+      break;
+    }
+    default: {
+      aResult = kPriorityUnknown;
+      break;
+    }
+  }
+}
+
+static const char* ToString(FetchPriority aFetchPriority) {
+  switch (aFetchPriority) {
+    case FetchPriority::Auto: {
+      return kFetchPriorityAttributeValueAuto;
+    }
+    case FetchPriority::Low: {
+      return kFetchPriorityAttributeValueLow;
+    }
+    case FetchPriority::High: {
+      return kFetchPriorityAttributeValueHigh;
+    }
+    default: {
+      MOZ_ASSERT_UNREACHABLE();
+      return kFetchPriorityAttributeValueAuto;
+    }
+  }
+}
+#endif  // DEBUG
+
+void LogPriorityMapping(LazyLogModule& aLazyLogModule,
+                        FetchPriority aFetchPriority,
+                        int32_t aSupportsPriority) {
+#ifdef DEBUG
+  nsDependentCString supportsPriority;
+  SupportsPriorityToString(aSupportsPriority, supportsPriority);
+  MOZ_LOG(aLazyLogModule, LogLevel::Debug,
+          ("Mapping priority: %s -> %s", ToString(aFetchPriority),
+           supportsPriority.get()));
+#endif  // DEBUG
+}
+}  // namespace mozilla::dom