text: /*    Copyright 2012 10gen Inc.
   *
   *    This program is free software: you can redistribute it and/or  modify
   *    it under the terms of the GNU Affero General Public License, version 3,
   *    as published by the Free Software Foundation.
   *
   *    This program is distributed in the hope that it will be useful,
   *    but WITHOUT ANY WARRANTY; without even the implied warranty of
   *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   *    GNU Affero General Public License for more details.
   *
   *    You should have received a copy of the GNU Affero General Public License
   *    along with this program.  If not, see <http://www.gnu.org/licenses/>.
   *
   *    As a special exception, the copyright holders give permission to link the
   *    code of portions of this program with the OpenSSL library under certain
   *    conditions as described in each individual source file and distribute
   *    linked combinations including the program with the OpenSSL library. You
   *    must comply with the GNU Affero General Public License in all respects
   *    for all of the code used other than as permitted herein. If you modify
   *    file(s) with this exception, you may extend this exception to your
   *    version of the file(s), but you are not obligated to do so. If you do not
   *    wish to do so, delete this exception statement from your version. If you
   *    delete this exception statement from all source files in the program,
   *    then also delete it in the license file.
   */
  
  #pragma once
  
  #include <boost/scoped_array.hpp>
  #include <string>
  
  #include "mongo/base/disallow_copying.h"
  #include "mongo/base/status.h"
  #include "mongo/base/string_data.h"
  #include "mongo/client/export_macros.h"
  #include "mongo/stdx/functional.h"
  
  namespace mongo {
  
  /**
   * Base class for the client side of a SASL authentication conversation.
   *
   * To use, create an instance, then use setParameter() to configure the authentication
   * parameters.  Once all parameters are set, call initialize() to initialize the client state
   * machine.  Finally, use repeated calls to step() to generate messages to send to the server
   * and process server responses.
   *
   * The required parameters vary by mechanism, but all mechanisms require parameterServiceName,
   * parameterServiceHostname, parameterMechanism and parameterUser.  All of the required
   * parameters must be UTF-8 encoded strings with no embedded NUL characters.  The
   * parameterPassword parameter is not constrained.
   */
  class MONGO_CLIENT_API SaslClientSession {
      MONGO_DISALLOW_COPYING(SaslClientSession);
  
  public:
      typedef stdx::function<SaslClientSession*(const std::string&)> SaslClientSessionFactoryFn;
      static SaslClientSessionFactoryFn create;
  
      /**
       * Identifiers of parameters used to configure a SaslClientSession.
       */
      enum Parameter {
          parameterServiceName = 0,
          parameterServiceHostname,
          parameterMechanism,
          parameterUser,
          parameterPassword,
          numParameters  // Must be last
      };
  
      SaslClientSession();
      virtual ~SaslClientSession();
  
      /**
       * Sets the parameter identified by "id" to "value".
       *
       * The value of "id" must be one of the legal values of Parameter less than numParameters.
       * May be called repeatedly for the same value of "id", with the last "value" replacing
       * previous values.
       *
       * The session object makes and owns a copy of the data in "value".
       */
      virtual void setParameter(Parameter id, const StringData& value);
  
      /**
       * Returns true if "id" identifies a parameter previously set by a call to setParameter().
       */
      virtual bool hasParameter(Parameter id);
  
      /**
       * Returns the value of a previously set parameter.
       *
       * If parameter "id" was never set, returns an empty StringData.  Note that a parameter may
       * be explicitly set to StringData(), so use hasParameter() to distinguish those cases.
       *
       * The session object owns the storage behind the returned StringData, which will remain
       * valid until setParameter() is called with the same value of "id", or the session object
       * goes out of scope.
       */
      virtual StringData getParameter(Parameter id);
  
      /**
       * Initializes a session for use.
       *
       * Call exactly once, after setting any parameters you intend to set via setParameter().
       */
      virtual Status initialize() = 0;
  
      /**
       * Takes one step of the SASL protocol on behalf of the client.
       *
       * Caller should provide data from the server side of the conversation in "inputData", or an
       * empty StringData() if none is available.  If the client should make a response to the
       * server, stores the response into "*outputData".
       *
       * Returns Status::OK() on success.  Any other return value indicates a failed
       * authentication, though the specific return value may provide insight into the cause of
       * the failure (e.g., ProtocolError, AuthenticationFailed).
       *
       * In the event that this method returns Status::OK(), consult the value of isDone() to
       * determine if the conversation has completed.  When step() returns Status::OK() and
       * isDone() returns true, authentication has completed successfully.
       */
      virtual Status step(const StringData& inputData, std::string* outputData) = 0;
  
      /**
       * Returns true if the authentication completed successfully.
       */
      virtual bool isDone() const = 0;
  
  private:
      /**
       * Buffer object that owns data for a single parameter.
       */
      struct DataBuffer {
          boost::scoped_array<char> data;
          size_t size;
      };
  
      /// Buffers for each of the settable parameters.
      DataBuffer _parameters[numParameters];
  };
  
  }  // namespace mongo
  