Certificate Transparency: Fetching of Signed Tree Heads (DRAFT)

components/certificate_transparency/tree_state_tracker.h

Index: components/certificate_transparency/tree_state_tracker.h
diff --git a/components/certificate_transparency/tree_state_tracker.h b/components/certificate_transparency/tree_state_tracker.h
new file mode 100644
index 0000000000000000000000000000000000000000..2073cdf97775bddd472921af49fe9c88ee4027a9
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+++ b/components/certificate_transparency/tree_state_tracker.h
@@ -0,0 +1,58 @@
+// Copyright 2015 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.
+
+#ifndef COMPONENTS_CERTIFICATE_TRANSPARENCY_TREE_STATE_TRACKER_H_
+#define COMPONENTS_CERTIFICATE_TRANSPARENCY_TREE_STATE_TRACKER_H_
+
+#include <map>
+#include <string>
+#include <vector>
+
+#include "base/memory/linked_ptr.h"
+#include "base/memory/scoped_ptr.h"
+#include "net/cert/ct_verifier.h"
+
+namespace net {
+class CTLogVerifier;
+
+namespace ct {
+struct SignedCertificateTimestamp;
+struct SignedTreeHead;
+}  // namespace ct
+
+}  // namespace net
+
+namespace certificate_transparency {
+
+class LogProofFetcher;
+
+// Tracks the state of the Merkle Trees of CT logs Chromium
+// knows about. For now, only stores Signed Tree Heads.

[Ryan Sleevi, 2015/06/29 11:58:13]

Comment nit: "For now" suggests there may be more, but you don't hint (via bug
or todo) what the more may be

+class TreeStateTracker : public net::CTVerifier::Observer {
+ public:
+  TreeStateTracker(scoped_ptr<LogProofFetcher> fetcher,
+                   const std::vector<linked_ptr<net::CTLogVerifier>>& ct_logs);
+  ~TreeStateTracker() override;
+
+  void OnSCTVerified(const net::ct::SignedCertificateTimestamp* sct,
+                     net::CTLogVerifier* verifier) override;
+
+ private:
+  void RefreshSTHs();
+  void OnSTHFetched(const std::string& log_id,
+                    const net::ct::SignedTreeHead& unverified_sth);
+
+  // Holds the latest STH fetched and verified for each log.
+  std::map<std::string, net::ct::SignedTreeHead> sths_;
+  // Fetcher for getting STHs and proofs from CT logs.
+  scoped_ptr<LogProofFetcher> fetcher_;
+  // List of CT logs to track.
+  std::map<std::string, linked_ptr<net::CTLogVerifier>> ct_logs_;
+
+  DISALLOW_COPY_AND_ASSIGN(TreeStateTracker);
+};
+
+}  // namespace certificate_transparency
+
+#endif // COMPONENTS_CERTIFICATE_TRANSPARENCY_TREE_STATE_TRACKER_H_