Added utility functions related to working with "facets".

components/password_manager/core/browser/affiliation_utils.h

Index: components/password_manager/core/browser/affiliation_utils.h
diff --git a/components/password_manager/core/browser/affiliation_utils.h b/components/password_manager/core/browser/affiliation_utils.h
new file mode 100644
index 0000000000000000000000000000000000000000..c2c3b035fb6d4b7f0c1301ee4412535153388ce7
--- /dev/null
+++ b/components/password_manager/core/browser/affiliation_utils.h
@@ -0,0 +1,129 @@
+// Copyright 2014 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// This file contains utilities related to working with "facets".
+//
+// A "facet" is defined as the manifestation of a logical application on a given
+// platform. For example, "My Bank" may have released an Android application
+// and a Web application accessible from a browser. These are all facets of the
+// "My Bank" logical application.
+//
+// Facets that belong to the same logical application are said to be affiliated
+// with each other. Conceptually, "affiliations" can be seen as an equivalence
+// relation defined over the set of all facets. Each equivalence class contains
+// facets that belong to the same logical application, and therefore should be
+// treated as synonymous for certain purposes, e.g., sharing credentials.
+//
+// A valid facet identifier will be a URI of the form:
+//
+//   * https://<host>[:<port>]/
+//      For web sites. Only HTTPS sites are supported, and URI must not contain
+//      components other than the scheme, host, and a port (which is optional).
+//
+//   * android://<cert_hash>@<package_name>/
+//      For Android applications. The <cert_hash> is hash of the certificate
+//      used to sign the APK, normally calculated as:
+//        echo -n -e "$PEM_KEY" | \
+//          openssl x509 -outform DER | \
+//          openssl sha -sha512 -binary | base64 | tr '+/' '-_'
+//
+// The canonical form of both kinds of facet URI should be calculated the same
+// way as it is calculated for a standard URL. Note that this will cause '='
+// padding characters in <cert_hash> to be percent encoded into "%3D".
+
+#ifndef COMPONENTS_PASSWORD_MANAGER_CORE_BROWSER_AFFILIATION_UTILS_H_
+#define COMPONENTS_PASSWORD_MANAGER_CORE_BROWSER_AFFILIATION_UTILS_H_
+
+#include <string>
+#include <vector>
+
+namespace password_manager {
+
+// Encapsulates a facet URI in canonical form.
+//
+// This is a very light-weight wrapper around an std::string containing the text
+// of the URI, and can be passed around as a value. The main reason this class
+// exists is to make it clearer in the code when a certain URI is known to be a
+// valid facet URI in canonical form, and to allow verifying/converting URIs to
+// such canonical form.
+//
+// Note that it would be impractical to use GURL to represent facet URIs, as
+// GURL has built-in logic to parse the rest of the URI according to its scheme,
+// and obviously, it does not recognize the "android" scheme. Therefore, after
+// parsing, everything ends up in the path component, which is not too helpful.
+class FacetURI {

[Mike West, 2014/12/03 22:58:35]

Nit: I think you should split this out into a separate file.

[engedy, 2014/12/08 20:53:16]

That would mean having really tiny files. How about renaming this to something
better?

+ public:
+  // As a light-weight std::string wrapper, allow copy and assign.
+  FacetURI();
+  FacetURI(const FacetURI&) = default;
+  FacetURI& operator=(const FacetURI&) = default;
+
+  // Constructs a FacetURI instance to encapsulates the canonical form of |uri|.

[Mike West, 2014/12/03 22:58:35]

s/encapsulates/encapsulate/

[engedy, 2014/12/08 20:53:16]

Done.

+  // The resulting instance will be invalid if |uri| was not a valid facet URI.
+  static FacetURI FromPotentiallyInvalidURI(const std::string& uri);
+
+  // Constructs a valid FacetURI instance from a valid |canonical_facet_uri|.

[Mike West, 2014/12/03 22:58:35]

Can you describe here what happens if an invalid URI is provided?

[engedy, 2014/12/08 20:53:16]

Done.

+  static FacetURI FromCanonicalFacetURI(const std::string& canonical_facet_uri);
+
+  // Comparison operators.
+  bool operator==(const FacetURI& other) const {
+    return canonical_uri_ == other.canonical_uri_;
+  }
+  bool operator!=(const FacetURI& other) const {
+    return canonical_uri_ != other.canonical_uri_;
+  }
+
+  // Relational operators so that FacetURI can be used in sorted containers.
+  bool operator<(const FacetURI& other) const {
+    return canonical_uri_ < other.canonical_uri_;
+  }
+  bool operator>(const FacetURI& other) const {
+    return canonical_uri_ > other.canonical_uri_;
+  }
+
+  // Returns whether or not this instance represents a valid facet identifier
+  // referring to either a Web or an Android application.
+  bool is_valid() const {
+    return is_valid_;
+  }
+
+  // Returns the text of the encapsulated canonical URI.
+  const std::string& canonical_uri() const {
+    return canonical_uri_;
+  }
+
+  // Returns whether or not this instance represents a valid facet identifier
+  // referring to a Web application.
+  bool IsValidWebFacetURI() const;
+
+  // Returns whether or not this instance represents a valid facet identifier
+  // referring to an Android application.
+  bool IsValidAndroidFacetURI() const;
+
+ private:
+  // Internal constructor to be used by the static factory methods.
+  FacetURI(const std::string& canonical_facet_uri, bool is_valid);
+
+  // Whether or not |canonical_uri_| contains a valid facet URI in canonical
+  // form.
+  bool is_valid_;
+
+  // The canonical form of the URI this instance was constructed with.
+  // If |is_valid_| is true, then this is also a valid facet URI.
+  std::string canonical_uri_;
+};
+
+// A collection of facets affiliated with each other, i.e. an equivalence class.
+typedef std::vector<FacetURI> AffiliatedFacets;
+
+// Returns whether or not equivalence classes |a| and |b| are equal, that is,
+// whether or not they consist of the same set of facets.
+//
+// Note that this will do some sorting, so it can be expensive for large inputs.
+bool AreEquivalenceClassesEqual(const AffiliatedFacets& a,
+                                const AffiliatedFacets& b);
+
+}  // namespace password_manager
+
+#endif  // COMPONENTS_PASSWORD_MANAGER_CORE_BROWSER_AFFILIATION_UTILS_H_