/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.apache.cassandra.auth;

import java.util.*;
import java.util.concurrent.Callable;
import java.util.concurrent.TimeUnit;

import com.google.common.base.*;
import com.google.common.base.Objects;
import com.google.common.collect.ImmutableSet;
import com.google.common.collect.Iterables;
import org.apache.commons.lang3.StringUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import org.apache.cassandra.concurrent.ScheduledExecutors;
import org.apache.cassandra.config.Config;
import org.apache.cassandra.config.DatabaseDescriptor;
import org.apache.cassandra.config.Schema;
import org.apache.cassandra.config.SchemaConstants;
import org.apache.cassandra.cql3.*;
import org.apache.cassandra.cql3.statements.SelectStatement;
import org.apache.cassandra.db.ConsistencyLevel;
import org.apache.cassandra.db.marshal.UTF8Type;
import org.apache.cassandra.exceptions.*;
import org.apache.cassandra.net.MessagingService;
import org.apache.cassandra.service.ClientState;
import org.apache.cassandra.service.QueryState;
import org.apache.cassandra.service.StorageService;
import org.apache.cassandra.transport.messages.ResultMessage;
import org.apache.cassandra.utils.ByteBufferUtil;
import org.mindrot.jbcrypt.BCrypt;

Responsible for the creation, maintenance and deletion of roles for the purposes of authentication and authorization. Role data is stored internally, using the roles and role_members tables in the system_auth keyspace. Additionally, if org.apache.cassandra.auth.PasswordAuthenticator is used, encrypted passwords are also stored in the system_auth.roles table. This coupling between the IAuthenticator and IRoleManager implementations exists because setting a role's password via CQL is done with a CREATE ROLE or ALTER ROLE statement, the processing of which is handled by IRoleManager. As IAuthenticator is concerned only with credentials checking and has no means to modify passwords, PasswordAuthenticator depends on CassandraRoleManager for those functions. Alternative IAuthenticator implementations may be used in conjunction with CassandraRoleManager, but WITH PASSWORD = 'password' will not be supported in CREATE/ALTER ROLE statements. Such a configuration could be implemented using a custom IRoleManager that extends CassandraRoleManager and which includes Option.PASSWORD in the Set<Option> returned from supportedOptions/alterableOptions. Any additional processing of the password itself (such as storing it in an alternative location) would be added in overridden createRole and alterRole implementations. /**
 * Responsible for the creation, maintenance and deletion of roles
 * for the purposes of authentication and authorization.
 * Role data is stored internally, using the roles and role_members tables
 * in the system_auth keyspace.
 *
 * Additionally, if org.apache.cassandra.auth.PasswordAuthenticator is used,
 * encrypted passwords are also stored in the system_auth.roles table. This
 * coupling between the IAuthenticator and IRoleManager implementations exists
 * because setting a role's password via CQL is done with a CREATE ROLE or
 * ALTER ROLE statement, the processing of which is handled by IRoleManager.
 * As IAuthenticator is concerned only with credentials checking and has no
 * means to modify passwords, PasswordAuthenticator depends on
 * CassandraRoleManager for those functions.
 *
 * Alternative IAuthenticator implementations may be used in conjunction with
 * CassandraRoleManager, but WITH PASSWORD = 'password' will not be supported
 * in CREATE/ALTER ROLE statements.
 *
 * Such a configuration could be implemented using a custom IRoleManager that
 * extends CassandraRoleManager and which includes Option.PASSWORD in the {@code Set<Option>}
 * returned from supportedOptions/alterableOptions. Any additional processing
 * of the password itself (such as storing it in an alternative location) would
 * be added in overridden createRole and alterRole implementations.
 */
public class CassandraRoleManager implements IRoleManager
{
    private static final Logger logger = LoggerFactory.getLogger(CassandraRoleManager.class);

    static final String DEFAULT_SUPERUSER_NAME = "cassandra";
    static final String DEFAULT_SUPERUSER_PASSWORD = "cassandra";

    // Transform a row in the AuthKeyspace.ROLES to a Role instance
    private static final Function<UntypedResultSet.Row, Role> ROW_TO_ROLE = new Function<UntypedResultSet.Row, Role>()
    {
        public Role apply(UntypedResultSet.Row row)
        {
            try
            {
                return new Role(row.getString("role"),
                         row.getBoolean("is_superuser"),
                         row.getBoolean("can_login"),
                         row.has("member_of") ? row.getSet("member_of", UTF8Type.instance)
                                              : Collections.<String>emptySet());
            }
            // Failing to deserialize a boolean in is_superuser or can_login will throw an NPE
            catch (NullPointerException e)
            {
                logger.warn("An invalid value has been detected in the {} table for role {}. If you are " +
                            "unable to login, you may need to disable authentication and confirm " +
                            "that values in that table are accurate", AuthKeyspace.ROLES, row.getString("role"));
                throw new RuntimeException(String.format("Invalid metadata has been detected for role %s", row.getString("role")), e);
            }

        }
    };

    public static final String LEGACY_USERS_TABLE = "users";
    // Transform a row in the legacy system_auth.users table to a Role instance,
    // used to fallback to previous schema on a mixed cluster during an upgrade
    private static final Function<UntypedResultSet.Row, Role> LEGACY_ROW_TO_ROLE = new Function<UntypedResultSet.Row, Role>()
    {
        public Role apply(UntypedResultSet.Row row)
        {
            return new Role(row.getString("name"),
                            row.getBoolean("super"),
                            true,
                            Collections.<String>emptySet());
        }
    };

    // 2 ** GENSALT_LOG2_ROUNDS rounds of hashing will be performed.
    private static final String GENSALT_LOG2_ROUNDS_PROPERTY = Config.PROPERTY_PREFIX + "auth_bcrypt_gensalt_log2_rounds";
    private static final int GENSALT_LOG2_ROUNDS = getGensaltLogRounds();

    static int getGensaltLogRounds()
    {
         int rounds = Integer.getInteger(GENSALT_LOG2_ROUNDS_PROPERTY, 10);
         if (rounds < 4 || rounds > 31)
         throw new ConfigurationException(String.format("Bad value for system property -D%s." +
                                                        "Please use a value between 4 and 31 inclusively",
                                                        GENSALT_LOG2_ROUNDS_PROPERTY));
         return rounds;
    }

    // NullObject returned when a supplied role name not found in AuthKeyspace.ROLES
    private static final Role NULL_ROLE = new Role(null, false, false, Collections.<String>emptySet());

    private SelectStatement loadRoleStatement;
    private SelectStatement legacySelectUserStatement;

    private final Set<Option> supportedOptions;
    private final Set<Option> alterableOptions;

    // Will be set to true when all nodes in the cluster are on a version which supports roles (i.e. 2.2+)
    private volatile boolean isClusterReady = false;

    public CassandraRoleManager()
    {
        supportedOptions = DatabaseDescriptor.getAuthenticator().getClass() == PasswordAuthenticator.class
                         ? ImmutableSet.of(Option.LOGIN, Option.SUPERUSER, Option.PASSWORD)
                         : ImmutableSet.of(Option.LOGIN, Option.SUPERUSER);
        alterableOptions = DatabaseDescriptor.getAuthenticator().getClass().equals(PasswordAuthenticator.class)
                         ? ImmutableSet.of(Option.PASSWORD)
                         : ImmutableSet.<Option>of();
    }

    public void setup()
    {
        loadRoleStatement = (SelectStatement) prepare("SELECT * from %s.%s WHERE role = ?",
                                                      SchemaConstants.AUTH_KEYSPACE_NAME,
                                                      AuthKeyspace.ROLES);
        // If the old users table exists, we may need to migrate the legacy authn
        // data to the new table. We also need to prepare a statement to read from
        // it, so we can continue to use the old tables while the cluster is upgraded.
        // Otherwise, we may need to create a default superuser role to enable others
        // to be added.
        if (Schema.instance.getCFMetaData(SchemaConstants.AUTH_KEYSPACE_NAME, "users") != null)
        {
            legacySelectUserStatement = prepareLegacySelectUserStatement();

            scheduleSetupTask(() -> {
                convertLegacyData();
                return null;
            });
        }
        else
        {
            scheduleSetupTask(() -> {
                setupDefaultRole();
                return null;
            });
        }
    }

    public Set<Option> supportedOptions()
    {
        return supportedOptions;
    }

    public Set<Option> alterableOptions()
    {
        return alterableOptions;
    }

    public void createRole(AuthenticatedUser performer, RoleResource role, RoleOptions options)
    throws RequestValidationException, RequestExecutionException
    {
        String insertCql = options.getPassword().isPresent()
                         ? String.format("INSERT INTO %s.%s (role, is_superuser, can_login, salted_hash) VALUES ('%s', %s, %s, '%s')",
                                         SchemaConstants.AUTH_KEYSPACE_NAME,
                                         AuthKeyspace.ROLES,
                                         escape(role.getRoleName()),
                                         options.getSuperuser().or(false),
                                         options.getLogin().or(false),
                                         escape(hashpw(options.getPassword().get())))
                         : String.format("INSERT INTO %s.%s (role, is_superuser, can_login) VALUES ('%s', %s, %s)",
                                         SchemaConstants.AUTH_KEYSPACE_NAME,
                                         AuthKeyspace.ROLES,
                                         escape(role.getRoleName()),
                                         options.getSuperuser().or(false),
                                         options.getLogin().or(false));
        process(insertCql, consistencyForRole(role.getRoleName()));
    }

    public void dropRole(AuthenticatedUser performer, RoleResource role) throws RequestValidationException, RequestExecutionException
    {
        process(String.format("DELETE FROM %s.%s WHERE role = '%s'",
                              SchemaConstants.AUTH_KEYSPACE_NAME,
                              AuthKeyspace.ROLES,
                              escape(role.getRoleName())),
                consistencyForRole(role.getRoleName()));
        removeAllMembers(role.getRoleName());
    }

    public void alterRole(AuthenticatedUser performer, RoleResource role, RoleOptions options)
    {
        // Unlike most of the other data access methods here, this does not use a
        // prepared statement in order to allow the set of assignments to be variable.
        String assignments = Joiner.on(',').join(Iterables.filter(optionsToAssignments(options.getOptions()),
                                                                  Predicates.notNull()));
        if (!Strings.isNullOrEmpty(assignments))
        {
            process(String.format("UPDATE %s.%s SET %s WHERE role = '%s'",
                                  SchemaConstants.AUTH_KEYSPACE_NAME,
                                  AuthKeyspace.ROLES,
                                  assignments,
                                  escape(role.getRoleName())),
                    consistencyForRole(role.getRoleName()));
        }
    }

    public void grantRole(AuthenticatedUser performer, RoleResource role, RoleResource grantee)
    throws RequestValidationException, RequestExecutionException
    {
        if (getRoles(grantee, true).contains(role))
            throw new InvalidRequestException(String.format("%s is a member of %s",
                                                            grantee.getRoleName(),
                                                            role.getRoleName()));
        if (getRoles(role, true).contains(grantee))
            throw new InvalidRequestException(String.format("%s is a member of %s",
                                                            role.getRoleName(),
                                                            grantee.getRoleName()));

        modifyRoleMembership(grantee.getRoleName(), role.getRoleName(), "+");
        process(String.format("INSERT INTO %s.%s (role, member) values ('%s', '%s')",
                              SchemaConstants.AUTH_KEYSPACE_NAME,
                              AuthKeyspace.ROLE_MEMBERS,
                              escape(role.getRoleName()),
                              escape(grantee.getRoleName())),
                consistencyForRole(role.getRoleName()));
    }

    public void revokeRole(AuthenticatedUser performer, RoleResource role, RoleResource revokee)
    throws RequestValidationException, RequestExecutionException
    {
        if (!getRoles(revokee, false).contains(role))
            throw new InvalidRequestException(String.format("%s is not a member of %s",
                                                            revokee.getRoleName(),
                                                            role.getRoleName()));

        modifyRoleMembership(revokee.getRoleName(), role.getRoleName(), "-");
        process(String.format("DELETE FROM %s.%s WHERE role = '%s' and member = '%s'",
                              SchemaConstants.AUTH_KEYSPACE_NAME,
                              AuthKeyspace.ROLE_MEMBERS,
                              escape(role.getRoleName()),
                              escape(revokee.getRoleName())),
                consistencyForRole(role.getRoleName()));
    }

    public Set<RoleResource> getRoles(RoleResource grantee, boolean includeInherited) throws RequestValidationException, RequestExecutionException
    {
        Set<RoleResource> roles = new HashSet<>();
        Role role = getRole(grantee.getRoleName());
        if (!role.equals(NULL_ROLE))
        {
            roles.add(RoleResource.role(role.name));
            collectRoles(role, roles, includeInherited);
        }
        return roles;
    }

    public Set<RoleResource> getAllRoles() throws RequestValidationException, RequestExecutionException
    {
        UntypedResultSet rows = process(String.format("SELECT role from %s.%s", SchemaConstants.AUTH_KEYSPACE_NAME, AuthKeyspace.ROLES), ConsistencyLevel.QUORUM);
        Iterable<RoleResource> roles = Iterables.transform(rows, new Function<UntypedResultSet.Row, RoleResource>()
        {
            public RoleResource apply(UntypedResultSet.Row row)
            {
                return RoleResource.role(row.getString("role"));
            }
        });
        return ImmutableSet.<RoleResource>builder().addAll(roles).build();
    }

    public boolean isSuper(RoleResource role)
    {
        try
        {
            return getRole(role.getRoleName()).isSuper;
        }
        catch (RequestExecutionException e)
        {
            logger.debug("Failed to authorize {} for super-user permission", role.getRoleName());
            throw new UnauthorizedException("Unable to perform authorization of super-user permission: " + e.getMessage(), e);
        }
    }

    public boolean canLogin(RoleResource role)
    {
        try
        {
            return getRole(role.getRoleName()).canLogin;
        }
        catch (RequestExecutionException e)
        {
            logger.debug("Failed to authorize {} for login permission", role.getRoleName());
            throw new UnauthorizedException("Unable to perform authorization of login permission: " + e.getMessage(), e);
        }
    }

    public Map<String, String> getCustomOptions(RoleResource role)
    {
        return Collections.emptyMap();
    }

    public boolean isExistingRole(RoleResource role)
    {
        return getRole(role.getRoleName()) != NULL_ROLE;
    }

    public Set<? extends IResource> protectedResources()
    {
        return ImmutableSet.of(DataResource.table(SchemaConstants.AUTH_KEYSPACE_NAME, AuthKeyspace.ROLES),
                               DataResource.table(SchemaConstants.AUTH_KEYSPACE_NAME, AuthKeyspace.ROLE_MEMBERS));
    }

    public void validateConfiguration() throws ConfigurationException
    {
    }

    /*
     * Create the default superuser role to bootstrap role creation on a clean system. Preemptively
     * gives the role the default password so PasswordAuthenticator can be used to log in (if
     * configured)
     */
    private static void setupDefaultRole()
    {
        if (StorageService.instance.getTokenMetadata().sortedTokens().isEmpty())
            throw new IllegalStateException("CassandraRoleManager skipped default role setup: no known tokens in ring");

        try
        {
            if (!hasExistingRoles())
            {
                QueryProcessor.process(String.format("INSERT INTO %s.%s (role, is_superuser, can_login, salted_hash) " +
                                                     "VALUES ('%s', true, true, '%s')",
                                                     SchemaConstants.AUTH_KEYSPACE_NAME,
                                                     AuthKeyspace.ROLES,
                                                     DEFAULT_SUPERUSER_NAME,
                                                     escape(hashpw(DEFAULT_SUPERUSER_PASSWORD))),
                                       consistencyForRole(DEFAULT_SUPERUSER_NAME));
                logger.info("Created default superuser role '{}'", DEFAULT_SUPERUSER_NAME);
            }
        }
        catch (RequestExecutionException e)
        {
            logger.warn("CassandraRoleManager skipped default role setup: some nodes were not ready");
            throw e;
        }
    }

    private static boolean hasExistingRoles() throws RequestExecutionException
    {
        // Try looking up the 'cassandra' default role first, to avoid the range query if possible.
        String defaultSUQuery = String.format("SELECT * FROM %s.%s WHERE role = '%s'", SchemaConstants.AUTH_KEYSPACE_NAME, AuthKeyspace.ROLES, DEFAULT_SUPERUSER_NAME);
        String allUsersQuery = String.format("SELECT * FROM %s.%s LIMIT 1", SchemaConstants.AUTH_KEYSPACE_NAME, AuthKeyspace.ROLES);
        return !QueryProcessor.process(defaultSUQuery, ConsistencyLevel.ONE).isEmpty()
               || !QueryProcessor.process(defaultSUQuery, ConsistencyLevel.QUORUM).isEmpty()
               || !QueryProcessor.process(allUsersQuery, ConsistencyLevel.QUORUM).isEmpty();
    }

    private void scheduleSetupTask(final Callable<Void> setupTask)
    {
        // The delay is to give the node a chance to see its peers before attempting the operation
        ScheduledExecutors.optionalTasks.schedule(new Runnable()
        {
            public void run()
            {
                // If not all nodes are on 2.2, we don't want to initialize the role manager as this will confuse 2.1
                // nodes (see CASSANDRA-9761 for details). So we re-schedule the setup for later, hoping that the upgrade
                // will be finished by then.
                if (!MessagingService.instance().areAllNodesAtLeast22())
                {
                    logger.trace("Not all nodes are upgraded to a version that supports Roles yet, rescheduling setup task");
                    scheduleSetupTask(setupTask);
                    return;
                }

                isClusterReady = true;
                try
                {
                    setupTask.call();
                }
                catch (Exception e)
                {
                    logger.info("Setup task failed with error, rescheduling");
                    scheduleSetupTask(setupTask);
                }
            }
        }, AuthKeyspace.SUPERUSER_SETUP_DELAY, TimeUnit.MILLISECONDS);
    }

    /*
     * Copy legacy auth data from the system_auth.users & system_auth.credentials tables to
     * the new system_auth.roles table. This setup is not performed if AllowAllAuthenticator
     * is configured (see Auth#setup).
     */
    private void convertLegacyData() throws Exception
    {
        try
        {
            // read old data at QUORUM as it may contain the data for the default superuser
            if (Schema.instance.getCFMetaData("system_auth", "users") != null)
            {
                logger.info("Converting legacy users");
                UntypedResultSet users = QueryProcessor.process("SELECT * FROM system_auth.users",
                                                                ConsistencyLevel.QUORUM);
                for (UntypedResultSet.Row row : users)
                {
                    RoleOptions options = new RoleOptions();
                    options.setOption(Option.SUPERUSER, row.getBoolean("super"));
                    options.setOption(Option.LOGIN, true);
                    createRole(null, RoleResource.role(row.getString("name")), options);
                }
                logger.info("Completed conversion of legacy users");
            }

            if (Schema.instance.getCFMetaData("system_auth", "credentials") != null)
            {
                logger.info("Migrating legacy credentials data to new system table");
                UntypedResultSet credentials = QueryProcessor.process("SELECT * FROM system_auth.credentials",
                                                                      ConsistencyLevel.QUORUM);
                for (UntypedResultSet.Row row : credentials)
                {
                    // Write the password directly into the table to avoid doubly encrypting it
                    QueryProcessor.process(String.format("UPDATE %s.%s SET salted_hash = '%s' WHERE role = '%s'",
                                                         SchemaConstants.AUTH_KEYSPACE_NAME,
                                                         AuthKeyspace.ROLES,
                                                         row.getString("salted_hash"),
                                                         row.getString("username")),
                                           consistencyForRole(row.getString("username")));
                }
                logger.info("Completed conversion of legacy credentials");
            }
        }
        catch (Exception e)
        {
            logger.info("Unable to complete conversion of legacy auth data (perhaps not enough nodes are upgraded yet). " +
                        "Conversion should not be considered complete");
            logger.trace("Conversion error", e);
            throw e;
        }
    }

    private SelectStatement prepareLegacySelectUserStatement()
    {
        return (SelectStatement) prepare("SELECT * FROM %s.%s WHERE name = ?",
                                         SchemaConstants.AUTH_KEYSPACE_NAME,
                                         LEGACY_USERS_TABLE);
    }

    private CQLStatement prepare(String template, String keyspace, String table)
    {
        try
        {
            return QueryProcessor.parseStatement(String.format(template, keyspace, table)).prepare(ClientState.forInternalCalls()).statement;
        }
        catch (RequestValidationException e)
        {
            throw new AssertionError(e); // not supposed to happen
        }
    }

    /*
     * Retrieve all roles granted to the given role. includeInherited specifies
     * whether to include only those roles granted directly or all inherited roles.
     */
    private void collectRoles(Role role, Set<RoleResource> collected, boolean includeInherited) throws RequestValidationException, RequestExecutionException
    {
        for (String memberOf : role.memberOf)
        {
            Role granted = getRole(memberOf);
            if (granted.equals(NULL_ROLE))
                continue;
            collected.add(RoleResource.role(granted.name));
            if (includeInherited)
                collectRoles(granted, collected, true);
        }
    }

    /*
     * Get a single Role instance given the role name. This never returns null, instead it
     * uses the null object NULL_ROLE when a role with the given name cannot be found. So
     * it's always safe to call methods on the returned object without risk of NPE.
     */
    private Role getRole(String name)
    {
        // If it exists, try the legacy users table in case the cluster
        // is in the process of being upgraded and so is running with mixed
        // versions of the authn schema.
        if (Schema.instance.getCFMetaData(SchemaConstants.AUTH_KEYSPACE_NAME, "users") == null)
            return getRoleFromTable(name, loadRoleStatement, ROW_TO_ROLE);
        else
        {
            if (legacySelectUserStatement == null)
                legacySelectUserStatement = prepareLegacySelectUserStatement();
            return getRoleFromTable(name, legacySelectUserStatement, LEGACY_ROW_TO_ROLE);
        }
    }

    private Role getRoleFromTable(String name, SelectStatement statement, Function<UntypedResultSet.Row, Role> function)
    throws RequestExecutionException, RequestValidationException
    {
        ResultMessage.Rows rows =
            statement.execute(QueryState.forInternalCalls(),
                              QueryOptions.forInternalCalls(consistencyForRole(name),
                                                            Collections.singletonList(ByteBufferUtil.bytes(name))),
                              System.nanoTime());
        if (rows.result.isEmpty())
            return NULL_ROLE;

        return function.apply(UntypedResultSet.create(rows.result).one());
    }

    /*
     * Adds or removes a role name from the membership list of an entry in the roles table table
     * (adds if op is "+", removes if op is "-")
     */
    private void modifyRoleMembership(String grantee, String role, String op)
    throws RequestExecutionException
    {
        process(String.format("UPDATE %s.%s SET member_of = member_of %s {'%s'} WHERE role = '%s'",
                              SchemaConstants.AUTH_KEYSPACE_NAME,
                              AuthKeyspace.ROLES,
                              op,
                              escape(role),
                              escape(grantee)),
                consistencyForRole(grantee));
    }

    /*
     * Clear the membership list of the given role
     */
    private void removeAllMembers(String role) throws RequestValidationException, RequestExecutionException
    {
        // Get the membership list of the the given role
        UntypedResultSet rows = process(String.format("SELECT member FROM %s.%s WHERE role = '%s'",
                                                      SchemaConstants.AUTH_KEYSPACE_NAME,
                                                      AuthKeyspace.ROLE_MEMBERS,
                                                      escape(role)),
                                        consistencyForRole(role));
        if (rows.isEmpty())
            return;

        // Update each member in the list, removing this role from its own list of granted roles
        for (UntypedResultSet.Row row : rows)
            modifyRoleMembership(row.getString("member"), role, "-");

        // Finally, remove the membership list for the dropped role
        process(String.format("DELETE FROM %s.%s WHERE role = '%s'",
                              SchemaConstants.AUTH_KEYSPACE_NAME,
                              AuthKeyspace.ROLE_MEMBERS,
                              escape(role)),
                consistencyForRole(role));
    }

    /*
     * Convert a map of Options from a CREATE/ALTER statement into
     * assignment clauses used to construct a CQL UPDATE statement
     */
    private Iterable<String> optionsToAssignments(Map<Option, Object> options)
    {
        return Iterables.transform(
                                  options.entrySet(),
                                  new Function<Map.Entry<Option, Object>, String>()
                                  {
                                      public String apply(Map.Entry<Option, Object> entry)
                                      {
                                          switch (entry.getKey())
                                          {
                                              case LOGIN:
                                                  return String.format("can_login = %s", entry.getValue());
                                              case SUPERUSER:
                                                  return String.format("is_superuser = %s", entry.getValue());
                                              case PASSWORD:
                                                  return String.format("salted_hash = '%s'", escape(hashpw((String) entry.getValue())));
                                              default:
                                                  return null;
                                          }
                                      }
                                  });
    }

    protected static ConsistencyLevel consistencyForRole(String role)
    {
        if (role.equals(DEFAULT_SUPERUSER_NAME))
            return ConsistencyLevel.QUORUM;
        else
            return ConsistencyLevel.LOCAL_ONE;
    }

    private static String hashpw(String password)
    {
        return BCrypt.hashpw(password, BCrypt.gensalt(GENSALT_LOG2_ROUNDS));
    }

    private static String escape(String name)
    {
        return StringUtils.replace(name, "'", "''");
    }

    
Executes the provided query.
This shouldn't be used during setup as this will directly return an error if the manager is not setup yet. Setup tasks
should use QueryProcessor.process directly.
/**
     * Executes the provided query.
     * This shouldn't be used during setup as this will directly return an error if the manager is not setup yet. Setup tasks
     * should use QueryProcessor.process directly.
     */
    private UntypedResultSet process(String query, ConsistencyLevel consistencyLevel) throws RequestValidationException, RequestExecutionException
    {
        if (!isClusterReady)
            throw new InvalidRequestException("Cannot process role related query as the role manager isn't yet setup. "
                                            + "This is likely because some of nodes in the cluster are on version 2.1 or earlier. "
                                            + "You need to upgrade all nodes to Cassandra 2.2 or more to use roles.");

        return QueryProcessor.process(query, consistencyLevel);
    }

    private static final class Role
    {
        private String name;
        private final boolean isSuper;
        private final boolean canLogin;
        private Set<String> memberOf;

        private Role(String name, boolean isSuper, boolean canLogin, Set<String> memberOf)
        {
            this.name = name;
            this.isSuper = isSuper;
            this.canLogin = canLogin;
            this.memberOf = memberOf;
        }

        public boolean equals(Object o)
        {
            if (this == o)
                return true;

            if (!(o instanceof Role))
                return false;

            Role r = (Role) o;
            return Objects.equal(name, r.name);
        }

        public int hashCode()
        {
            return Objects.hashCode(name);
        }
    }
}