nss_crypto_module_delegate.h

// Copyright 2013 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 CRYPTO_NSS_CRYPTO_MODULE_DELEGATE_H_
#define CRYPTO_NSS_CRYPTO_MODULE_DELEGATE_H_

#include <string>

#include "base/memory/ref_counted.h"

namespace crypto {

// PK11_SetPasswordFunc is a global setting.  An implementation of
// CryptoModuleBlockingPasswordDelegate should be passed using wincx() as the
// user data argument (|wincx|) to relevant NSS functions, which the global
// password handler will call to do the actual work. This delegate should only
// be used in NSS calls on worker threads due to the blocking nature.
class CryptoModuleBlockingPasswordDelegate
    : public base::RefCountedThreadSafe<CryptoModuleBlockingPasswordDelegate> {
 public:

  // Return a value suitable for passing to the |wincx| argument of relevant NSS
  // functions. This should be used instead of passing the object pointer
  // directly to avoid accidentally casting a pointer to a subclass to void* and
  // then casting back to a pointer of the base class
  void* wincx() { return this; }

  // Requests a password to unlock |slot_name|. The interface is synchronous
  // because NSS cannot issue an asynchronous request. |retry| is true if this
  // is a request for the retry and we previously returned the wrong password.
  // The implementation should set |*cancelled| to true if the user cancelled
  // instead of entering a password, otherwise it should return the password the
  // user entered.
  virtual std::string RequestPassword(const std::string& slot_name, bool retry,
                                      bool* cancelled) = 0;

 protected:
  friend class base::RefCountedThreadSafe<CryptoModuleBlockingPasswordDelegate>;

  virtual ~CryptoModuleBlockingPasswordDelegate() {}
};

}  // namespace crypto

#endif  // CRYPTO_NSS_CRYPTO_MODULE_DELEGATE_H_