Initial implementation for CertNetFetcher.

net/cert/cert_net_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 NET_CERT_CERT_NET_FETCHER_H_
+#define NET_CERT_CERT_NET_FETCHER_H_
+
+#include <set>
+#include <vector>
+
+#include "base/callback.h"
+#include "base/memory/ref_counted.h"
+#include "base/memory/scoped_ptr.h"
+#include "base/time/time.h"
+#include "net/base/net_export.h"
+#include "url/gurl.h"
+
+namespace net {
+
+class URLRequestContext;
+
+// CertNetFetcher is a helper for fetching AIA URLs and CRL URLs.
+//
+// It manages the outstanding requests, and applies policies specific to
+// certificate network fetches. For instance:
+//   * Enforces a maximum timeout on responses
+//   * Enforces a maximum size on responses
+//   * Restricts URLs to http://
+//
+// The CertNetFetcher is initialized by giving it a URLRequestContext for the
+// network dependencies. Note that it does not maintain its own in-memory cache
+// for responses. Instead it is reliant on the URLRequestContext providing an
+// HTTP cache if this is desired.
+//
+// -------------------------
+// Cancellation of requests
+// -------------------------
+//
+//  * Network requests started by the CertNetFetcher can be cancelled using
+//    CancelRequest(). Cancellation means the callback will not be invoked.
+//
+//  * If the CertNetFetcher is deleted then any outstanding
+//    requests are automatically cancelled.
+//
+//  * Cancelling a request more than once is an error (and may result in a
+//    use-after-free).
+//
+//  * Cancelling a request within the execution of a callback is allowed.
+//
+//  * Deleting the CertNetFetcher from within the execution of a callback is
+//    allowed.
+//
+// -------------------------
+// Threading
+// -------------------------
+//
+// The CertNetFetcher is expected to be operated from a single thread, which has
+// an IO message loop. The URLRequestContext will be accessed from this same
+// thread, and callbacks will be posted to this message loop.
+//
+// For more details see the early design document:
+//   https://docs.google.com/a/chromium.org/document/d/1CdS9YOnPdAyVZBJqHY7ZJ6tUlU71OCvX8kHnaVhf144/edit
+class NET_EXPORT CertNetFetcher {

[mattm, 2015/02/10 05:22:14]

Maybe inherit NonThreadSafe and add CalledOnValidThread dchecks?

[eroman, 2015/02/11 03:51:52]

Done.

+ private:
+  struct Request;
+
+ public:
+  typedef base::Callback<void(int, const std::vector<uint8_t>&)> FetchCallback;
+
+  enum RequestType {
+    REQUEST_TYPE_CA_ISSUERS,
+    REQUEST_TYPE_OCSP,
+    REQUEST_TYPE_CRL,
+  };
+
+  enum HttpMethod {
+    HTTP_METHOD_GET,
+    HTTP_METHOD_POST,
+  };
+
+  struct RequestParams {
+    RequestParams(const GURL& url, RequestType type);
+
+    bool operator<(const RequestParams& other) const;
+
+    GURL url;
+    HttpMethod http_method;
+    size_t max_response_size_in_bytes;
+
+    // If set to a value <= 0 then means "no timeout".
+    base::TimeDelta timeout;
+
+    // IMPORTANT: When adding fields to this structure, update operator<().
+  };
+
+  typedef Request* RequestId;
+
+  // Initilizes CertNetFetcher using the specified URLRequestContext for issuing
+  // requests. |context| must remain valid for the entire lifetime of the
+  // CertNetFetcher.
+  explicit CertNetFetcher(URLRequestContext* context);
+
+  ~CertNetFetcher();
+
+  // Starts an asynchronous request to fetch the given URL. On completion
+  // |callback| will be invoked.
+  //
+  // Completion of the request will never occur synchronously. In other words it
+  // is guaranteed that |callback| will only be invoked once the Fetch*() method
+  // has returned.
+  RequestId Fetch(scoped_ptr<RequestParams> request_params,
+                  FetchCallback callback);
+
+  // Cancels the indicated request. It is an error to call this function on a
+  // request which has already completed (including one that was already
+  // cancelled).
+  void CancelRequest(RequestId request);
+
+ private:
+  class Job;
+  struct JobToRequestParamsComparator;
+
+  struct JobComparator {
+    bool operator()(const scoped_refptr<Job>& job1,
+                    const scoped_refptr<Job>& job2) const;
+  };
+
+  typedef std::set<scoped_refptr<Job>, JobComparator> JobSet;
+
+  // Finds a job with a matching RequestPararms or returns NULL if there was no
+  // match.
+  Job* FindJob(const RequestParams& params);
+
+  // Removes |job| from the in progress jobs. This may cause the final reference
+  // to |job| to be released.
+  void RemoveJob(Job* job);
+
+  // The in-progress jobs.
+  JobSet jobs_;
+
+  // Not owned. CertNetFetcher must outlive the URLRequestContext.
+  URLRequestContext* context_;
+
+  DISALLOW_COPY_AND_ASSIGN(CertNetFetcher);
+};
+
+}  // namespace net
+
+#endif  // NET_CERT_CERT_NET_FETCHER_H_