Gave the GetOriginBoundCertificate an asynchronous interface because certificate

net/base/origin_bound_cert_service.h

 // Copyright (c) 2011 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_BASE_ORIGIN_BOUND_CERT_SERVICE_H_
 #define NET_BASE_ORIGIN_BOUND_CERT_SERVICE_H_
 #pragma once
 
+#include <map>
 #include <string>
 
+#include "base/basictypes.h"
 #include "base/memory/ref_counted.h"
 #include "base/memory/scoped_ptr.h"
+#include "base/threading/non_thread_safe.h"
+#include "net/base/completion_callback.h"
 #include "net/base/net_api.h"
 
 namespace net {
 
+class OriginBoundCertServiceJob;
+class OriginBoundCertServiceWorker;

[wtc, 2011/08/05 01:48:21]

I wonder if these two types should be Job and Worker
nested inside the OriginBoundCertService class.

 class OriginBoundCertStore;
 
 // A class for creating and fetching origin bound certs.
+// Inherits from NonThreadSafe in order to use the function
+// |CalledOnValidThread|.
 class NET_API OriginBoundCertService
-    : public base::RefCountedThreadSafe<OriginBoundCertService> {
+    : public base::RefCountedThreadSafe<OriginBoundCertService>,
+      NON_EXPORTED_BASE(public base::NonThreadSafe) {
  public:
+  // Opaque type used to cancel a request.
+  typedef void* RequestHandle;
+
   // This object owns origin_bound_cert_store.
   explicit OriginBoundCertService(
       OriginBoundCertStore* origin_bound_cert_store);
 
   ~OriginBoundCertService();
 
   // TODO(rkn): Specify certificate type (RSA or DSA).
-  // TODO(rkn): Key generation can be time consuming, so this should have an
-  // asynchronous interface.
   // Fetches the origin bound cert for the specified origin if one exists
   // and creates one otherwise. On success, |private_key_result| stores a
   // DER-encoded PrivateKeyInfo struct, and |cert_result| stores a DER-encoded
   // certificate.

[wtc, 2011/08/05 01:48:21]

Add comments to describe the async behavior, out_req, and
the return value.

|private_key_result| and |cert_result| have been renamed.
Make the same change to the comments on lines 65-66 below.

-  bool GetOriginBoundCert(const std::string& origin,
-                          std::string* private_key_result,
-                          std::string* cert_result);
+  int GetOriginBoundCert(const std::string& origin,
+                         std::string* private_key,
+                         std::string* cert,
+                         CompletionCallback* callback,
+                         RequestHandle* out_req);
+
+  // Cancels the specified request. |req| is the handle returned by Verify().

[wtc, 2011/08/05 01:48:21]

Verify => GetOriginBoundCert

+  // After a request is canceled, its completion callback will not be called.
+  void CancelRequest(RequestHandle req);
 
   // Public only for unit testing.
   int GetCertCount();
+  uint64 requests() const { return requests_; }
+  uint64 cache_hits() const {return cache_hits_; }
+  uint64 inflight_joins() const {return inflight_joins_; }
 
  private:
+  friend class OriginBoundCertServiceWorker;  // Calls HandleResult.
+
+  // On success, |private_key_result| stores a DER-encoded PrivateKeyInfo
+  // struct, and |cert_result| stores a DER-encoded certificate. Returns
+  // OK if successful and ERR_FAILED otherwise.

[wtc, 2011/08/05 01:48:21]

If the only possible return values are OK and ERR_FAILED,
please have the function return bool.

+  // |serial_number| is passed in because it is created with the function
+  // base::RandInt, which opens the file /dev/urandom, which cannot be done on
+  // a worker thread.
+  int GenerateCert(const std::string& origin,
+                   uint32 serial_number,
+                   std::string* private_key,
+                   std::string* cert);
+
+  void HandleResult(const std::string& origin,
+                    int error,
+                    const std::string& private_key,
+                    const std::string& cert);
+
   scoped_ptr<OriginBoundCertStore> origin_bound_cert_store_;
+
+  // inflight_ maps from an origin to an active generation which is taking
+  // place.
+  std::map<std::string, OriginBoundCertServiceJob*> inflight_;
+
+  uint64 requests_;
+  uint64 cache_hits_;
+  uint64 inflight_joins_;
+
+  DISALLOW_COPY_AND_ASSIGN(OriginBoundCertService);
 };
 
 }  // namespace net
 
 #endif  // NET_BASE_ORIGIN_BOUND_CERT_SERVICE_H_