Certificate Transparency: Fetching consistency proofs.

components/certificate_transparency/log_proof_fetcher.h

 // 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_LOG_PROOF_FETCHER_H_
 #define COMPONENTS_CERTIFICATE_TRANSPARENCY_LOG_PROOF_FETCHER_H_
 
 #include <map>
 #include <string>
+#include <vector>
 
 #include "base/callback.h"
 #include "base/macros.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/memory/weak_ptr.h"
 #include "net/url_request/url_request.h"
+#include "url/gurl.h"
 
 namespace base {
 class Value;
 }  // namespace base
 
 namespace net {
 
 class URLRequestContext;
 
 namespace ct {
@@ skipping 20 matching lines @@
   using SignedTreeHeadFetchedCallback =
       base::Callback<void(const std::string& log_id,
                           const net::ct::SignedTreeHead& signed_tree_head)>;
 
   // Callback for failure of Signed Tree Head retrieval. Called with the log_id
   // that the log fetching was requested for and a net error code of the
   // failure.
   using FetchFailedCallback = base::Callback<
       void(const std::string& log_id, int net_error, int http_response_code)>;
 
+  // Callback for successful retrieval of consistency proofs between two
+  // STHs. Called with the log_id of the log the consistency belongs to (as
+  // supplied by the caller to FetchConsistencyProof) and the vector of
+  // proof nodes.
+  using ConsistencyProofFetchedCallback =
+      base::Callback<void(const std::string& log_id,
+                          const std::vector<std::string>& consistency_proof)>;
+
   explicit LogProofFetcher(net::URLRequestContext* request_context);
   ~LogProofFetcher() override;
 
   // Fetch the latest Signed Tree Head from the log identified by |log_id|
   // from |base_log_url|. The |log_id| will be passed into the callbacks to
   // identify the log the retrieved Signed Tree Head belongs to.
   // The callbacks won't be invoked if the request is destroyed before
   // fetching is completed.
   // It is possible, but does not make a lot of sense, to have multiple
   // Signed Tree Head fetching requests going out to the same log, since
   // they are likely to return the same result.
   // TODO(eranm): Think further about whether multiple requests to the same
   // log imply cancellation of previous requests, should be coalesced or handled
   // independently.
   void FetchSignedTreeHead(
       const GURL& base_log_url,
       const std::string& log_id,
       const SignedTreeHeadFetchedCallback& fetched_callback,
       const FetchFailedCallback& failed_callback);
 
+  // Fetch a consistency proof between the Merkle trees identified by
+  // |old_tree_size| and |new_tree_size| of the log identified by |log_id|
+  // from |base_log_url|.
+  //
+  // See the documentation of FetchSignedTreeHead regarding request destruction
+  // and multiple requests to the same log.
+  void FetchConsistencyProof(
+      const GURL& base_log_url,
+      const std::string& log_id,
+      uint64_t old_tree_size,
+      uint64_t new_tree_size,
+      const ConsistencyProofFetchedCallback& fetched_callback,
+      const FetchFailedCallback& failed_callback);
+
   // net::URLRequest::Delegate
   void OnResponseStarted(net::URLRequest* request) override;
   void OnReadCompleted(net::URLRequest* request, int bytes_read) override;
 
  private:
   struct FetchState;
   // Handles the final result of a URLRequest::Read call on |request|.
   // Returns true if another read should be started, false if the read
   // failed completely or we have to wait for OnResponseStarted to
   // be called.
@@ skipping 10 matching lines @@
   void RequestComplete(net::URLRequest* request);
   // Deletes the request and associated FetchState from the internal map.
   void CleanupRequest(net::URLRequest* request);
   // Invokes the failure callback with the supplied arguments, then cleans up
   // the request.
   void InvokeFailureCallback(net::URLRequest* request,
                              int net_error,
                              int http_response_code);
 
   // Callbacks for parsing the STH's JSON by the SafeJsonParser
-  void OnSTHJsonParseSuccess(net::URLRequest* request,
-                             scoped_ptr<base::Value> parsed_json);
-  void OnSTHJsonParseError(net::URLRequest* request, const std::string& error);
+  void OnJsonParseSuccess(net::URLRequest* request,
+                          scoped_ptr<base::Value> parsed_json);
+  void OnJsonParseError(net::URLRequest* request, const std::string& error);
+
+  // Creates and starts a URLRequest for actual fetching from the log.
+  // takes ownership of |fetch_state| and puts it (together with the
+  // URLRequest created) into |inflight_requests_|.
+  void FetchFromLog(const GURL& base_log_url,
+                    const std::string& log_id,
+                    FetchState* fetch_state);
 
   net::URLRequestContext* const request_context_;
 
   // Owns the contained requests, as well as FetchState.
   std::map<net::URLRequest*, FetchState*> inflight_requests_;
 
   base::WeakPtrFactory<LogProofFetcher> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(LogProofFetcher);
 };
 
 }  // namespace certificate_transparency
 
 #endif  // COMPONENTS_CERTIFICATE_TRANSPARENCY_LOG_PROOF_FETCHER_H_