1 files changed, 147 insertions, 0 deletions
diff --git a/dom/html/HTMLDNSPrefetch.h b/dom/html/HTMLDNSPrefetch.h
new file mode 100644
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+++ b/dom/html/HTMLDNSPrefetch.h
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+/* -*- 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/. */
+
+#ifndef mozilla_dom_HTMLDNSPrefetch_h___
+#define mozilla_dom_HTMLDNSPrefetch_h___
+
+#include "nsCOMPtr.h"
+#include "nsIRequest.h"
+#include "nsString.h"
+#include "nsIDNSService.h"
+
+class nsITimer;
+class nsIURI;
+namespace mozilla {
+
+class OriginAttributes;
+
+namespace net {
+class NeckoParent;
+}  // namespace net
+
+namespace dom {
+class Document;
+class Element;
+
+class SupportsDNSPrefetch;
+
+class HTMLDNSPrefetch {
+ public:
+  // The required aDocument parameter is the context requesting the prefetch -
+  // under certain circumstances (e.g. headers, or security context) associated
+  // with the context the prefetch will not be performed.
+  static bool IsAllowed(Document* aDocument);
+
+  static nsresult Initialize();
+  static nsresult Shutdown();
+
+  // Call one of the Prefetch* methods to start the lookup.
+  //
+  // The URI versions will defer DNS lookup until pageload is
+  // complete, while the string versions submit the lookup to
+  // the DNS system immediately. The URI version is somewhat lighter
+  // weight, but its request is also more likely to be dropped due to a
+  // full queue and it may only be used from the main thread.
+  //
+  // If you are planning to use the methods with the OriginAttributes param, be
+  // sure that you pass a partitioned one. See StoragePrincipalHelper.h to know
+  // more.
+
+  enum class Priority {
+    Low,
+    Medium,
+    High,
+  };
+  static nsresult Prefetch(SupportsDNSPrefetch&, Element&, Priority);
+  static nsresult Prefetch(
+      const nsAString& host, bool isHttps,
+      const OriginAttributes& aPartitionedPrincipalOriginAttributes,
+      nsIRequest::TRRMode aTRRMode, Priority);
+  static nsresult CancelPrefetch(
+      const nsAString& host, bool isHttps,
+      const OriginAttributes& aPartitionedPrincipalOriginAttributes,
+      nsIRequest::TRRMode aTRRMode, Priority, nsresult aReason);
+  static nsresult CancelPrefetch(SupportsDNSPrefetch&, Element&, Priority,
+                                 nsresult aReason);
+  static void ElementDestroyed(Element&, SupportsDNSPrefetch&);
+
+ private:
+  static nsIDNSService::DNSFlags PriorityToDNSServiceFlags(Priority);
+
+  static nsresult Prefetch(
+      const nsAString& host, bool isHttps,
+      const OriginAttributes& aPartitionedPrincipalOriginAttributes,
+      nsIDNSService::DNSFlags flags);
+  static nsresult CancelPrefetch(
+      const nsAString& hostname, bool isHttps,
+      const OriginAttributes& aPartitionedPrincipalOriginAttributes,
+      nsIDNSService::DNSFlags flags, nsresult aReason);
+
+  friend class net::NeckoParent;
+};
+
+// Elements that support DNS prefetch are expected to subclass this.
+class SupportsDNSPrefetch {
+ public:
+  bool IsInDNSPrefetch() { return mInDNSPrefetch; }
+  void SetIsInDNSPrefetch() { mInDNSPrefetch = true; }
+  void ClearIsInDNSPrefetch() { mInDNSPrefetch = false; }
+
+  void DNSPrefetchRequestStarted() {
+    mDNSPrefetchDeferred = false;
+    mDNSPrefetchRequested = true;
+  }
+
+  void DNSPrefetchRequestDeferred() {
+    mDNSPrefetchDeferred = true;
+    mDNSPrefetchRequested = false;
+  }
+
+  bool IsDNSPrefetchRequestDeferred() const { return mDNSPrefetchDeferred; }
+
+  // This could be a virtual function or something like that, but that would
+  // cause our subclasses to grow by two pointers, rather than just 1 byte at
+  // most.
+  nsIURI* GetURIForDNSPrefetch(Element& aOwner);
+
+ protected:
+  SupportsDNSPrefetch()
+      : mInDNSPrefetch(false),
+        mDNSPrefetchRequested(false),
+        mDNSPrefetchDeferred(false),
+        mDestroyedCalled(false) {}
+
+  void CancelDNSPrefetch(Element&);
+  void TryDNSPrefetch(Element&);
+
+  // This MUST be called on the destructor of the Element subclass.
+  // Our own destructor ensures that.
+  void Destroyed(Element& aOwner) {
+    MOZ_DIAGNOSTIC_ASSERT(!mDestroyedCalled,
+                          "Multiple calls to SupportsDNSPrefetch::Destroyed?");
+    mDestroyedCalled = true;
+    if (mInDNSPrefetch) {
+      HTMLDNSPrefetch::ElementDestroyed(aOwner, *this);
+    }
+  }
+
+  ~SupportsDNSPrefetch() {
+    MOZ_DIAGNOSTIC_ASSERT(mDestroyedCalled,
+                          "Need to call SupportsDNSPrefetch::Destroyed "
+                          "from the owner element");
+  }
+
+ private:
+  bool mInDNSPrefetch : 1;
+  bool mDNSPrefetchRequested : 1;
+  bool mDNSPrefetchDeferred : 1;
+  bool mDestroyedCalled : 1;
+};
+
+}  // namespace dom
+}  // namespace mozilla
+
+#endif