1 files changed, 92 insertions, 0 deletions
diff --git a/dom/security/SRIMetadata.h b/dom/security/SRIMetadata.h
new file mode 100644
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+++ b/dom/security/SRIMetadata.h
@@ -0,0 +1,92 @@
+/* -*- 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_SRIMetadata_h
+#define mozilla_dom_SRIMetadata_h
+
+#include "nsTArray.h"
+#include "nsString.h"
+#include "SRICheck.h"
+
+namespace mozilla {
+namespace dom {
+
+class SRIMetadata final {
+  friend class SRICheck;
+
+ public:
+  static const uint32_t MAX_ALTERNATE_HASHES = 256;
+  static const int8_t UNKNOWN_ALGORITHM = -1;
+
+  /**
+   * Create an empty metadata object.
+   */
+  SRIMetadata() : mAlgorithmType(UNKNOWN_ALGORITHM), mEmpty(true) {}
+
+  /**
+   * Split a string token into the components of an SRI metadata
+   * attribute.
+   */
+  explicit SRIMetadata(const nsACString& aToken);
+
+  /**
+   * Returns true when this object's hash algorithm is weaker than the
+   * other object's hash algorithm.
+   */
+  bool operator<(const SRIMetadata& aOther) const;
+
+  /**
+   * Not implemented. Should not be used.
+   */
+  bool operator>(const SRIMetadata& aOther) const;
+
+  /**
+   * Add another metadata's hash to this one.
+   */
+  SRIMetadata& operator+=(const SRIMetadata& aOther);
+
+  /**
+   * Returns true when the two metadata use the same hash algorithm.
+   */
+  bool operator==(const SRIMetadata& aOther) const;
+
+  bool IsEmpty() const { return mEmpty; }
+  bool IsMalformed() const { return mHashes.IsEmpty() || mAlgorithm.IsEmpty(); }
+  bool IsAlgorithmSupported() const {
+    return mAlgorithmType != UNKNOWN_ALGORITHM;
+  }
+  bool IsValid() const { return !IsMalformed() && IsAlgorithmSupported(); }
+
+  uint32_t HashCount() const { return mHashes.Length(); }
+  void GetHash(uint32_t aIndex, nsCString* outHash) const;
+  void GetAlgorithm(nsCString* outAlg) const { *outAlg = mAlgorithm; }
+  void GetHashType(int8_t* outType, uint32_t* outLength) const;
+
+  const nsString& GetIntegrityString() const { return mIntegrityString; }
+
+  // Return true if:
+  // * this SRI is empty
+  // * the other SRI has a stronger hash algorithm
+  // * the other SRI has the same hash algorithm and also the same set of values
+  // otherwise, return false.
+  //
+  // This method simply checks if the other SRI is stronger or identical to this
+  // one, so that a load that has been checked against that other SRI has the
+  // same or higher level of trust than this SRI provides.
+  bool CanTrustBeDelegatedTo(const SRIMetadata& aOther) const;
+
+ private:
+  CopyableTArray<nsCString> mHashes;
+  nsString mIntegrityString;
+  nsCString mAlgorithm;
+  int8_t mAlgorithmType;
+  bool mEmpty;
+};
+
+}  // namespace dom
+}  // namespace mozilla
+
+#endif  // mozilla_dom_SRIMetadata_h