/* Copyright (c) 2017, 2024, Oracle and/or its affiliates.

This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License, version 2.0,
as published by the Free Software Foundation.

This program is designed to work with certain software (including
but not limited to OpenSSL) that is licensed under separate terms,
as designated in a particular file or component or in included license
documentation.  The authors of MySQL hereby grant you an additional
permission to link the program and your derivative works with the
separately licensed software that they have either included with
the program or referenced in the documentation.

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 General Public License, version 2.0, for more details.

You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301  USA */

#include "component_common.h"
#include "registry_imp.h"

// pfs instrumentation headers
#include <mysql/components/services/mysql_rwlock.h>

/**
  @page PAGE_COMPONENTS_REGISTRY The Service Registry Service
  The Service Registry is a central part of Components subsystem. It maintains
  a list of the Service Implementations and allow acquiring them by any actor
  that has a reference to main Registry Service Implementation. For each Service
  a reference counter is maintained to make sure no one can remove any Service
  Implementation being actively used.
  The Service Implementations can be acquired by the Service name or by the full
  Service Implementation name.
  For each Service a default Service Implementation is distinguished, the first
  one to be added, but it is possible to change it at will at any point.

  A convenient RAII-style wrapper on Service acquisition and automatic release
  is provided, the my_service<T> class.
*/

static PSI_rwlock_key key_rwlock_LOCK_registry;

struct my_h_service_iterator_imp {
  my_service_registry::const_iterator m_it;
  minimal_chassis::rwlock_scoped_lock m_lock;
};

struct my_h_service_metadata_iterator_imp {
  my_metadata::const_iterator m_it;
  minimal_chassis::rwlock_scoped_lock m_lock;
};

static PSI_rwlock_info all_registry_rwlocks[] = {
    {&::key_rwlock_LOCK_registry, "LOCK_registry", PSI_FLAG_SINGLETON, 0,
     PSI_DOCUMENT_ME}};

static void init_registry_psi_keys(void) {
  const char *category = "components";
  int count;

  count = static_cast<int>(array_elements(all_registry_rwlocks));
  mysql_rwlock_register(category, all_registry_rwlocks, count);
}

/**
  Initializes registry for usage. Initializes RW lock, all other structures
  should be empty. Shouldn't be called multiple times.
*/
void mysql_registry_imp::init() {
  init_registry_psi_keys();
  mysql_rwlock_init(key_rwlock_LOCK_registry,
                    &mysql_registry_imp::LOCK_registry);
}

/**
  De-initializes registry. De-initializes RW lock, all other structures
  are cleaned up.
*/
void mysql_registry_imp::deinit() {
  mysql_registry_no_lock_imp::deinit();
  mysql_rwlock_destroy(&mysql_registry_imp::LOCK_registry);
}

/**
  De-initializes RW lock
*/
void mysql_registry_imp::rw_lock_deinit() {
  mysql_rwlock_destroy(&mysql_registry_imp::LOCK_registry);
}

/**
  Locks whole registry for write. For internal use only.

  @return A lock acquired wrapped into RAII object.
*/
minimal_chassis::rwlock_scoped_lock
mysql_registry_imp::lock_registry_for_write() {
  return minimal_chassis::rwlock_scoped_lock(&LOCK_registry, true, __FILE__,
                                             __LINE__);
}

/**
  Finds and acquires a Service by name. A name of the Service or the Service
  Implementation can be specified. In case of the Service name, the default
  Service Implementation for Service specified will be returned.

  @param service_name Name of Service or Service Implementation to acquire.
  @param [out] out_service Pointer to Service handle to set acquired Service.
  @return Status of performed operation
  @retval false success
  @retval true failure
*/
DEFINE_BOOL_METHOD(mysql_registry_imp::acquire,
                   (const char *service_name, my_h_service *out_service)) {
  minimal_chassis::rwlock_scoped_lock lock(&LOCK_registry, false, __FILE__,
                                           __LINE__);

  return mysql_registry_no_lock_imp::acquire(service_name, out_service);
}

/**
  Finds a Service by name. If there is a Service Implementation with the same
  Component part of name as the input Service then the found Service is
  returned.

  @param service_name Name of Service or Service Implementation to acquire.
  @param service Service handle already acquired Service Implementation.
  @param [out] out_service Pointer to Service Implementation handle to set
    acquired Service Implementation.
  @return Status of performed operation
  @retval false success
  @retval true failure
*/
DEFINE_BOOL_METHOD(mysql_registry_imp::acquire_related,
                   (const char *service_name, my_h_service service,
                    my_h_service *out_service)) {
  minimal_chassis::rwlock_scoped_lock lock(&mysql_registry_imp::LOCK_registry,
                                           false, __FILE__, __LINE__);

  return mysql_registry_no_lock_imp::acquire_related(service_name, service,
                                                     out_service);
}

/**
  Releases the Service Implementation previously acquired. After the call to
  this method the usage of the Service Implementation handle will lead to
  unpredicted results.

  @param service Service Implementation handle of already acquired Service.
  @return Status of performed operation
  @retval false success
  @retval true failure
*/
DEFINE_BOOL_METHOD(mysql_registry_imp::release, (my_h_service service)) {
  minimal_chassis::rwlock_scoped_lock lock(&mysql_registry_imp::LOCK_registry,
                                           false, __FILE__, __LINE__);

  return mysql_registry_no_lock_imp::release(service);
}

/**
  Registers a new Service Implementation. If it is the first Service
  Implementation for the specified Service then it is made a default one.

  @param service_implementation_name Name of the Service Implementation to
    register.
  @param ptr Pointer to the Service Implementation structure.
  @return Status of performed operation
  @retval false success
  @retval true failure
*/
DEFINE_BOOL_METHOD(mysql_registry_imp::register_service,
                   (const char *service_implementation_name,
                    my_h_service ptr)) {
  minimal_chassis::rwlock_scoped_lock lock(&mysql_registry_imp::LOCK_registry,
                                           true, __FILE__, __LINE__);

  return mysql_registry_no_lock_imp::register_service(
      service_implementation_name, ptr);
}

/**
  Removes previously registered Service Implementation from registry. If it is
  the default one for specified Service then any one still registered is made
  default. If there is no other, the default entry is removed from the
  Registry too.

  @param service_implementation_name Name of the Service Implementation to
    unregister.
  @return Status of performed operation
  @retval false success
  @retval true Failure. May happen when Service is still being referenced.
*/
DEFINE_BOOL_METHOD(mysql_registry_imp::unregister,
                   (const char *service_implementation_name)) {
  minimal_chassis::rwlock_scoped_lock lock(&mysql_registry_imp::LOCK_registry,
                                           true, __FILE__, __LINE__);

  return mysql_registry_no_lock_imp::unregister(service_implementation_name);
}

/**
  Sets new default Service Implementation for corresponding Service name.

  @param service_implementation_name Name of the Service Implementation to
    set as default one.
  @return Status of performed operation
  @retval false success
  @retval true failure
*/
DEFINE_BOOL_METHOD(mysql_registry_imp::set_default,
                   (const char *service_implementation_name)) {
  minimal_chassis::rwlock_scoped_lock lock(&mysql_registry_imp::LOCK_registry,
                                           true, __FILE__, __LINE__);

  return mysql_registry_no_lock_imp::set_default(service_implementation_name);
}

/**
  Creates iterator that iterates through all registered Service
  Implementations. If successful it leaves read lock on the Registry until
  iterator is released. The starting point of iteration may be specified
  to be on one particular Service Implementation. The iterator will move
  through all Service Implementations and additionally through all default
  Service Implementation additionally, i.e. the default Service Implementation
  will be returned twice. If no name is specified for search, iterator will be
  positioned on the first Service Implementation.

  @param service_name_pattern Name of Service or Service Implementation to
    start iteration from. May be empty string or NULL pointer, in which case
    iteration starts from the first Service Implementation.
  @param [out] out_iterator Pointer to the Service Implementation iterator
    handle.
  @return Status of performed operation
  @retval false success
  @retval true failure
*/
DEFINE_BOOL_METHOD(mysql_registry_imp::iterator_create,
                   (const char *service_name_pattern,
                    my_h_service_iterator *out_iterator)) {
  try {
    *out_iterator = {};

    /* This read lock on whole registry will be held, until the iterator is
      released. */
    minimal_chassis::rwlock_scoped_lock lock(&mysql_registry_imp::LOCK_registry,
                                             false, __FILE__, __LINE__);

    my_service_registry::const_iterator r =
        (!service_name_pattern || !*service_name_pattern)
            ? mysql_registry_no_lock_imp::service_registry.cbegin()
            : mysql_registry_no_lock_imp::service_registry.find(
                  service_name_pattern);
    if (r == mysql_registry_no_lock_imp::service_registry.cend()) {
      return true;
    }

    if (service_name_pattern && *service_name_pattern) {
      /*
        If the query was of the format <service_name> or
        <service_name>.<implementation_name> then make sure that there exists at
        least one service matching the criteria. If not, there is no point
        returning the iterator because it would invariably point to a service
        other than what's caller is looking for.
      */
      if (strncmp(r->first, service_name_pattern,
                  std::min(strlen(r->first), strlen(service_name_pattern))))
        return true;
    }

    *out_iterator = new my_h_service_iterator_imp{r, std::move(lock)};
    return false;
  } catch (...) {
  }
  return true;
}

/**
  Releases Service implementations iterator. Releases read lock on registry.

  @param iterator Service Implementation iterator handle.
*/
DEFINE_METHOD(void, mysql_registry_imp::iterator_release,
              (my_h_service_iterator iterator)) {
  try {
    my_h_service_iterator_imp *iter =
        reinterpret_cast<my_h_service_iterator_imp *>(iterator);

    if (!iter) return;

    delete iter;
  } catch (...) {
  }
}

/**
  Gets name of Service pointed to by iterator. The pointer returned will last
  at least up to the moment of call to the release() method on the iterator.

  @param iterator Service Implementation iterator handle.
  @param [out] out_name Pointer to string with name to set result pointer to.
  @return Status of performed operation
  @retval false success
  @retval true Failure, may be caused when called on iterator that went
    through all values already.
*/
DEFINE_BOOL_METHOD(mysql_registry_imp::iterator_get,
                   (my_h_service_iterator iterator, const char **out_name)) {
  try {
    *out_name = nullptr;

    if (!iterator) return true;

    my_service_registry::const_iterator &iter =
        reinterpret_cast<my_h_service_iterator_imp *>(iterator)->m_it;

    if (iter != mysql_registry_no_lock_imp::service_registry.cend()) {
      *out_name = iter->second->name_c_str();

      return false;
    }
  } catch (...) {
  }
  return true;
}

/**
  Advances specified iterator to next element. Will succeed but return true if
  it reaches one-past-last element.

  @param iterator Service Implementation iterator handle.
  @return Status of performed operation and validity of iterator after
    operation.
  @retval false success
  @retval true Failure or called on iterator that was on last element.
*/
DEFINE_BOOL_METHOD(mysql_registry_imp::iterator_next,
                   (my_h_service_iterator iterator)) {
  try {
    if (!iterator) return true;

    my_service_registry::const_iterator &iter =
        reinterpret_cast<my_h_service_iterator_imp *>(iterator)->m_it;

    if (iter != mysql_registry_no_lock_imp::service_registry.cend()) {
      ++iter;
      return iter == mysql_registry_no_lock_imp::service_registry.cend();
    }
  } catch (...) {
  }
  return true;
}

/**
  Checks if specified iterator is valid, i.e. have not reached one-past-last
  element.

  @param iterator Service Implementation iterator handle.
  @return Validity of iterator
  @retval false Valid
  @retval true Invalid or reached one-past-last element.
*/
DEFINE_BOOL_METHOD(mysql_registry_imp::iterator_is_valid,
                   (my_h_service_iterator iterator)) {
  try {
    if (!iterator) return true;

    my_service_registry::const_iterator &iter =
        reinterpret_cast<my_h_service_iterator_imp *>(iterator)->m_it;

    return iter == mysql_registry_no_lock_imp::service_registry.cend();
  } catch (...) {
  }
  return true;
}

/* This includes metadata-related method implementations that are shared
  by registry and dynamic_loader, so we don't duplicate the code. Following
  defines set up all required symbols. Unfortunately they are not only the
  types, but also static members with different name, so usage of templates
  is not enough to reuse that part of code. */
#define REGISTRY_IMP mysql_registry_imp
#define REGISTRY mysql_registry_no_lock_imp::service_registry
#define REGISTRY_TYPE my_service_registry
#define LOCK mysql_registry_imp::LOCK_registry
#define ITERATOR_TYPE my_h_service_iterator_imp
#define METADATA_ITERATOR_TYPE my_h_service_metadata_iterator_imp
#define OBJECT_ITERATOR my_h_service_iterator
#define METADATA_ITERATOR my_h_service_metadata_iterator

#include "registry_metadata.cc.inc"

/* static members for mysql_registry_imp */
mysql_rwlock_t mysql_registry_imp::LOCK_registry;