Bug 1641936 - Add a generic principal hash key. r=bholley

Differential Revision: https://phabricator.services.mozilla.com/D77501

caps/PrincipalHashKey.h

@@ -0,0 +1,58 @@
+/* -*- 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_PrincipalHashKey_h
+#define mozilla_PrincipalHashKey_h
+
+#include "BasePrincipal.h"
+#include "PLDHashTable.h"
+#include "mozilla/Unused.h"
+#include "nsCOMPtr.h"
+#include "nsHashKeys.h"
+
+namespace mozilla {
+
+class PrincipalHashKey : public PLDHashEntryHdr {
+ public:
+  using KeyType = nsIPrincipal*;
+  using KeyTypePointer = const nsIPrincipal*;
+
+  explicit PrincipalHashKey(const nsIPrincipal* aKey)
+      : mPrincipal(const_cast<nsIPrincipal*>(aKey)) {
+    MOZ_ASSERT(aKey);
+    MOZ_COUNT_CTOR(PrincipalHashKey);
+  }
+  PrincipalHashKey(PrincipalHashKey&& aKey)
+      : mPrincipal(std::move(aKey.mPrincipal)) {
+    MOZ_COUNT_CTOR(PrincipalHashKey);
+  }
+
+  MOZ_COUNTED_DTOR(PrincipalHashKey)
+
+  nsIPrincipal* GetKey() const { return mPrincipal; }
+
+  bool KeyEquals(const nsIPrincipal* aKey) const {
+    return BasePrincipal::Cast(mPrincipal)
+        ->FastEquals(const_cast<nsIPrincipal*>(aKey));
+  }
+
+  static const nsIPrincipal* KeyToPointer(const nsIPrincipal* aKey) {
+    return aKey;
+  }
+  static PLDHashNumber HashKey(const nsIPrincipal* aKey) {
+    auto* bp = BasePrincipal::Cast(aKey);
+    return HashGeneric(bp->GetOriginNoSuffixHash(), bp->GetOriginSuffixHash());
+  }
+
+  enum { ALLOW_MEMMOVE = true };
+
+ protected:
+  nsCOMPtr<nsIPrincipal> mPrincipal;
+};
+
+}  // namespace mozilla
+
+#endif

caps/moz.build

@@ -35,6 +35,7 @@ EXPORTS.mozilla = [
     'NullPrincipal.h',
     'NullPrincipalURI.h',
     'OriginAttributes.h',
+    'PrincipalHashKey.h',
     'SystemPrincipal.h',
 ]
 

toolkit/components/antitracking/TemporaryAccessGrantObserver.h

@@ -7,7 +7,7 @@
 #ifndef mozilla_temporaryaccessgrantobserver_h
 #define mozilla_temporaryaccessgrantobserver_h
 
-#include "mozilla/BasePrincipal.h"
+#include "mozilla/PrincipalHashKey.h"
 #include "nsCOMPtr.h"
 #include "nsHashKeys.h"
 #include "nsIObserver.h"
@@ -23,21 +23,20 @@ namespace mozilla {
 
 class PermissionManager;
 
-class TemporaryAccessGrantCacheKey : public PLDHashEntryHdr {
+class TemporaryAccessGrantCacheKey : public PrincipalHashKey {
  public:
   typedef std::pair<nsCOMPtr<nsIPrincipal>, nsCString> KeyType;
   typedef const KeyType* KeyTypePointer;
 
   explicit TemporaryAccessGrantCacheKey(KeyTypePointer aKey)
-      : mPrincipal(aKey->first), mType(aKey->second) {}
+      : PrincipalHashKey(aKey->first), mType(aKey->second) {}
   TemporaryAccessGrantCacheKey(TemporaryAccessGrantCacheKey&& aOther) = default;
 
   ~TemporaryAccessGrantCacheKey() = default;
 
   KeyType GetKey() const { return std::make_pair(mPrincipal, mType); }
   bool KeyEquals(KeyTypePointer aKey) const {
-    return !!mPrincipal == !!aKey->first && mType == aKey->second &&
-           (mPrincipal ? (mPrincipal->Equals(aKey->first)) : true);
+    return PrincipalHashKey::KeyEquals(aKey->first) && mType == aKey->second;
   }
 
   static KeyTypePointer KeyToPointer(KeyType& aKey) { return &aKey; }
@@ -46,15 +45,13 @@ class TemporaryAccessGrantCacheKey : public PLDHashEntryHdr {
       return 0;
     }
 
-    BasePrincipal* bp = BasePrincipal::Cast(aKey->first);
-    return HashGeneric(bp->GetOriginNoSuffixHash(), bp->GetOriginSuffixHash(),
+    return HashGeneric(PrincipalHashKey::HashKey(aKey->first),
                        HashString(aKey->second));
   }
 
   enum { ALLOW_MEMMOVE = true };
 
  private:
-  nsCOMPtr<nsIPrincipal> mPrincipal;
   nsCString mType;
 };