/* Copyright (c) 2015, 2021, 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 also distributed 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 included with MySQL.

   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 "sql/dd/impl/sdi.h"

#include "my_rapidjson_size_t.h"  // IWYU pragma: keep

#include <rapidjson/document.h>      // rapidjson::GenericValue
#include <rapidjson/error/en.h>      // rapidjson::GetParseError_En
#include <rapidjson/prettywriter.h>  // rapidjson::PrettyWrite
#include <rapidjson/stringbuffer.h>
#include <stddef.h>
#include <stdint.h>
#include <sys/types.h>
#include <algorithm>
#include <functional>
#include <string>
#include <vector>

#include "m_ctype.h"
#include "m_string.h"  // STRING_WITH_LEN
#include "my_dbug.h"
#include "my_inttypes.h"
#include "my_sys.h"
#include "mysql/udf_registration_types.h"
#include "mysql_version.h"  // MYSQL_VERSION_ID
#include "mysqld_error.h"
#include "prealloced_array.h"
#include "sql/auth/sql_security_ctx.h"
#include "sql/dd/cache/dictionary_client.h"  // dd::Dictionary_client
#include "sql/dd/impl/dictionary_impl.h"  // dd::Dictionary_impl::get_target_dd_version
#include "sql/dd/impl/sdi_impl.h"         // sdi read/write functions
#include "sql/dd/impl/sdi_tablespace.h"  // dd::sdi_tablespace::store
#include "sql/dd/impl/sdi_utils.h"       // dd::checked_return
#include "sql/dd/object_id.h"            // dd::Object_id
#include "sql/dd/sdi_file.h"             // dd::sdi_file::store
#include "sql/dd/sdi_fwd.h"
#include "sql/dd/types/abstract_table.h"
#include "sql/dd/types/column.h"      // dd::Column
#include "sql/dd/types/index.h"       // dd::Index
#include "sql/dd/types/partition.h"   // dd::Partition
#include "sql/dd/types/schema.h"      // dd::Schema
#include "sql/dd/types/table.h"       // dd::Table
#include "sql/dd/types/tablespace.h"  // dd::Tablespace
#include "sql/handler.h"              // ha_resolve_by_name_raw
#include "sql/mdl.h"
#include "sql/sql_class.h"  // THD
#include "sql/sql_plugin_ref.h"
#include "sql/strfunc.h"  // lex_cstring_handle

/**
  @defgroup sdi Serialized Dictionary Information
  @ingroup Runtime_Environment
  @{
  Code to serialize and deserialize data dictionary objects, and for
  storing and retrieving the serialized representation from files or
  tablespaces.

  @file
  Definition of all sdi functions, except those that are -
  (de)serialize() member function in data dictionary objects -
  function templates which are defined in sdi_impl.h

  The file is made up of 4 groups:
  - @ref sdi_cc_internal
  - @ref sdi_internal
  - @ref sdi_api
  - @ref sdi_ut
  @}
*/

/**
  @defgroup sdi_cc_internal TU-internal definitions
  @ingroup sdi
  @{
  Functions and classes internal to the
  translation unit in the anonymous namespace.
*/

using namespace dd::sdi_utils;

namespace {
const dd::String_type empty_ = "";

char *generic_buf_handle(Byte_buffer *buf, size_t sz) {
  if (buf->reserve(sz)) {
    assert(false);
    return nullptr;
  }
  return &(*(buf->begin()));
}
}  // namespace

/** @} */  // sdi_cc_internal

namespace dd {
/**
  @defgroup sdi_internal SDI Internal
  @ingroup sdi

  Objects internal to sdi-creation, and not callable from general server code.
*/

/**
  Opaque context which keeps reusable resources needed during
  serialization.
*/

class Sdi_wcontext {
  /** A reusable byte buffer for e.g. base64 encoding. */
  Byte_buffer m_buf;
  /** Thread context */
  THD *m_thd;
  /** Pointer to schema name to use for schema references in SDI */
  const String_type *m_schema_name;

  /** Flag indicating that an error has occurred */
  bool m_error;

  friend char *buf_handle(Sdi_wcontext *wctx, size_t sz);

  friend const String_type &lookup_schema_name(Sdi_wcontext *wctx);

 public:
  Sdi_wcontext(THD *thd, const String_type *schema_name)
      : m_thd(thd), m_schema_name(schema_name), m_error(false) {}

  bool error() const { return m_error; }
  void set_error() { m_error = true; }
  THD *thd() const { return m_thd; }
};

char *buf_handle(Sdi_wcontext *wctx, size_t sz) {
  return generic_buf_handle(&wctx->m_buf, sz);
}

const String_type &lookup_schema_name(Sdi_wcontext *wctx) {
  return *wctx->m_schema_name;
}

template <typename T>
String_type generic_serialize(THD *thd, const char *dd_object_type,
                              size_t dd_object_type_size, const T &dd_obj,
                              const String_type *schema_name) {
  dd::Sdi_wcontext wctx(thd, schema_name);
  dd::RJ_StringBuffer buf;
  dd::Sdi_writer w(buf);

  w.StartObject();
  w.String(STRING_WITH_LEN("mysqld_version_id"));
  w.Uint64(MYSQL_VERSION_ID);

  w.String(STRING_WITH_LEN("dd_version"));
  w.Uint(Dictionary_impl::get_target_dd_version());

  w.String(STRING_WITH_LEN("sdi_version"));
  w.Uint64(SDI_VERSION);

  w.String(STRING_WITH_LEN("dd_object_type"));
  w.String(dd_object_type, dd_object_type_size);

  w.String(STRING_WITH_LEN("dd_object"));
  dd_obj.serialize(&wctx, &w);
  w.EndObject();

  return (wctx.error() ? empty_ : String_type(buf.GetString(), buf.GetSize()));
}

const String_type &lookup_tablespace_name(Sdi_wcontext *wctx [[maybe_unused]],
                                          dd::Object_id id [[maybe_unused]]) {
  if (wctx->thd() == nullptr || id == INVALID_OBJECT_ID) {
    return empty_;
  }

  dd::cache::Dictionary_client &dc = *wctx->thd()->dd_client();

  // The tablespace object may not have MDL (ALTER)
  // Need to use acquire_uncached_uncommitted to get name for MDL
  dd::Tablespace *tblspc_ = nullptr;
  if (dc.acquire_uncached_uncommitted(id, &tblspc_)) {
    wctx->set_error();
    return empty_;
  }
  if (tblspc_ == nullptr) {
    // Tablespace has been dropped by txn?
    wctx->set_error();
    return empty_;
  }

  if (mdl_lock(wctx->thd(), MDL_key::TABLESPACE, "", tblspc_->name(),
               MDL_INTENTION_EXCLUSIVE)) {
    wctx->set_error();
    return empty_;
  }

  const Tablespace *tsp = nullptr;
  if (dc.acquire(id, &tsp)) {
    wctx->set_error();
    return empty_;
  }
  assert(tsp != nullptr);

  return tsp->name();
}

/**
  Opaque context which keeps reusable resoureces needed during
  deserialization.
*/

class Sdi_rcontext {
  /** A reusable byte buffer for e.g. base64 decoding. */
  Byte_buffer buf;

  /** Column objects created during deserialization */
  dd_vector<Column *> m_column_object_opx;

  /** Index objects created during deserialization */
  dd_vector<Index *> m_index_object_opx;

  /** Thread context */
  THD *m_thd;

  /** Target dd version from SDI */
  uint m_target_dd_version;

  /** Sdi version from SDI */
  std::uint64_t m_sdi_version;

  /** Flag indicating that an error has occurred */
  bool m_error;

  friend void track_object(Sdi_rcontext *rctx, Column *column_object);
  friend void track_object(Sdi_rcontext *rctx, Index *index_object);

  friend Index *get_by_opx(Sdi_rcontext *rctx, const Index *, uint opx);
  friend Column *get_by_opx(Sdi_rcontext *rctx, const Column *, uint opx);

  friend char *buf_handle(Sdi_rcontext *rctx, size_t sz);

  friend bool lookup_schema_ref(Sdi_rcontext *rctx, const String_type &name,
                                dd::Object_id *idp);
  friend bool lookup_tablespace_ref(Sdi_rcontext *rctx, const String_type &name,
                                    Object_id *idp);

 public:
  Sdi_rcontext(THD *thd, uint target_dd_version, std::uint64_t sdi_version)
      : m_thd(thd),
        m_target_dd_version(target_dd_version),
        m_sdi_version(sdi_version),
        m_error(false) {}

  String_type m_schema_name;

  bool error() const { return m_error; }
};

template <typename T>
void generic_track_object(dd_vector<T *> *tvp, T *t) {
  assert(t->ordinal_position() > 0);
  uint opx = t->ordinal_position() - 1;
  dd_vector<T *> &tv = *tvp;

  if (opx >= tv.size()) {
    tv.resize(opx + 1);
  }
  tv[opx] = t;
}

void track_object(Sdi_rcontext *sdictx, Column *column_object) {
  generic_track_object(&sdictx->m_column_object_opx, column_object);
}

void track_object(Sdi_rcontext *sdictx, Index *index_object) {
  generic_track_object(&sdictx->m_index_object_opx, index_object);
}

Index *get_by_opx(dd::Sdi_rcontext *sdictx, const Index *, uint opx) {
  return sdictx->m_index_object_opx[opx];
}

Column *get_by_opx(dd::Sdi_rcontext *sdictx, const Column *, uint opx) {
  return sdictx->m_column_object_opx[opx];
}

char *buf_handle(Sdi_rcontext *rctx, size_t sz) {
  return generic_buf_handle(&rctx->buf, sz);
}

template <typename T>
bool generic_lookup_ref(THD *thd, MDL_key::enum_mdl_namespace mdlns,
                        const String_type &name, dd::Object_id *idp) {
  if (thd == nullptr) {
    return false;
  }

  // Acquire MDL here so that it becomes possible to acquire the
  // tablespace/schema to look up its id in the current DD
  if (mdlns == MDL_key::TABLESPACE) {
    if (mdl_lock(thd, mdlns, "", name, MDL_INTENTION_EXCLUSIVE)) {
      return true;
    }
  } else {
    if (mdl_lock(thd, mdlns, name, "", MDL_INTENTION_EXCLUSIVE)) {
      return true;
    }
  }

  dd::cache::Dictionary_client *dc = thd->dd_client();
  dd::cache::Dictionary_client::Auto_releaser releaser(dc);

  const T *p = nullptr;
  // TODO: Split in two. Use error flag in ctx object
  if (dc->acquire(name, &p) || p == nullptr) {
    return true;
  }
  *idp = p->id();
  return false;
}

bool lookup_schema_ref(Sdi_rcontext *sdictx, const String_type &name,
                       dd::Object_id *idp) {
  sdictx->m_schema_name = name;
  *idp = INVALID_OBJECT_ID;
  return false;
}

bool lookup_tablespace_ref(Sdi_rcontext *sdictx, const String_type &name,
                           Object_id *idp) {
  return generic_lookup_ref<Tablespace>(sdictx->m_thd, MDL_key::TABLESPACE,
                                        name, idp);
}

/** @{ */  // sdi_cc_internal

/**
  @defgroup sdi_api SDI API
  @ingroup sdi

  Definition of externally visible functions and classes, declared in sdi.h
  @{
*/

Sdi_type serialize(THD *thd, const Table &table,
                   const String_type &schema_name) {
  return generic_serialize(thd, STRING_WITH_LEN("Table"), table, &schema_name);
}

Sdi_type serialize(const Tablespace &tablespace) {
  return generic_serialize(nullptr, STRING_WITH_LEN("Tablespace"), tablespace,
                           nullptr);
}

/**
   Default checker which implements the traditional (strict)
   compatibility check: MYSQL_VERSION less than or equal, dd_version
   equal, and sdi_version equal.
*/
bool CheckDefaultCompatibility(const RJ_Document &doc) {
  assert(doc.HasMember("mysqld_version_id"));

  const RJ_Value &mysqld_version_id = doc["mysqld_version_id"];
  assert(mysqld_version_id.IsUint64());
#if !defined(XTRABACKUP)
  if (mysqld_version_id.GetUint64() > std::uint64_t(MYSQL_VERSION_ID)) {
    // Cannot deserialize SDIs from newer versions.
    my_error(ER_IMP_INCOMPATIBLE_MYSQLD_VERSION, MYF(0),
             mysqld_version_id.GetUint64(), std::uint64_t(MYSQL_VERSION_ID));
    return true;
  }
#endif /* !XTRABACKUP */

  assert(doc.HasMember("dd_version"));
  const RJ_Value &dd_version_val = doc["dd_version"];
  assert(dd_version_val.IsUint());
#if !defined(XTRABACKUP)
  uint dd_version = dd_version_val.GetUint();
  if (dd_version != Dictionary_impl::get_target_dd_version()) {
    // Incompatible change
    my_error(ER_IMP_INCOMPATIBLE_DD_VERSION, MYF(0), dd_version,
             Dictionary_impl::get_target_dd_version());
    return true;
  }
#endif /* !XTRABACKUP */

  assert(doc.HasMember("sdi_version"));
  const RJ_Value &sdi_version_val = doc["sdi_version"];
  assert(sdi_version_val.IsUint64());
#if !defined(XTRABACKUP)
  std::uint64_t sdi_version_ = sdi_version_val.GetUint64();
  if (sdi_version_ != SDI_VERSION) {
    // Incompatible change
    my_error(ER_IMP_INCOMPATIBLE_SDI_VERSION, MYF(0), sdi_version_,
             SDI_VERSION);
    return true;
  }
#endif /* !XTRABACKUP */
  return false;
}

template <class Dd_type>
bool generic_deserialize(THD *thd, const Sdi_type &sdi,
                         const String_type &object_type_name [[maybe_unused]],
                         Dd_type *dst,
                         const SdiCompatibilityChecker &comp_checker,
                         String_type *schema_name_from_sdi) {
  RJ_Document doc;
  doc.Parse<0>(sdi.c_str());
  if (doc.HasParseError()) {
    my_error(ER_INVALID_JSON_DATA, MYF(0), "deserialize()",
             rapidjson::GetParseError_En(doc.GetParseError()));
    return true;
  }

  if (comp_checker(doc)) {
    return checked_return(true);
  }

  assert(doc.HasMember("dd_object_type"));
  RJ_Value &dd_object_type_val = doc["dd_object_type"];
  assert(dd_object_type_val.IsString());
  String_type dd_object_type(dd_object_type_val.GetString());
  assert(dd_object_type == object_type_name);

  assert(doc.HasMember("dd_object"));
  RJ_Value &dd_object_val = doc["dd_object"];
  assert(dd_object_val.IsObject());

  assert(doc.HasMember("dd_version"));
  assert(doc.HasMember("sdi_version"));
  Sdi_rcontext rctx(thd, doc["dd_version"].GetUint(),
                    doc["sdi_version"].GetUint());
  if (dst->deserialize(&rctx, dd_object_val)) {
    return checked_return(true);
  }
  if (schema_name_from_sdi != nullptr) {
    *schema_name_from_sdi = std::move(rctx.m_schema_name);
  }

  return false;
}

/**
  Deserialize a dd::Table object.

  Populates the dd::Table object provided with data from sdi string.
  Note! Additional objects are dynamically allocated and added to the
  top-level Schema object, which assumes ownership.

  @param thd thread context
  @param sdi  serialized representation of schema (as a json string)
  @param dst_table empty top-level object
  @param comp_checker callable which will be used to determine if the SDI is
         compatible
  @param deser_schema_name name of schema containing the table

  @return error status
    @retval false if successful
    @retval true otherwise
*/
bool deserialize(THD *thd, const Sdi_type &sdi, Table *dst_table,
                 SdiCompatibilityChecker comp_checker,
                 String_type *deser_schema_name) {
  return generic_deserialize(thd, sdi, "Table", dst_table, comp_checker,
                             deser_schema_name);
}

/**
  Deserialize a dd::Tablespace object.

  Populates the dd::Tablespace object provided with data from sdi string.
  Note! Additional objects are dynamically allocated and added to the
  top-level Tablespace object, which assumes ownership.

  @param thd thread context
  @param sdi  serialized representation of schema (as a json string)
  @param dst_tablespace empty top-level object
  @param comp_checker callable which will be used to determine if the SDI is
         compatible.

  @return error status
    @retval false if successful
    @retval true otherwise
*/
bool deserialize(THD *thd, const Sdi_type &sdi, Tablespace *dst_tablespace,
                 SdiCompatibilityChecker comp_checker) {
  return generic_deserialize(thd, sdi, "Tablespace", dst_tablespace,
                             comp_checker, nullptr);
}

namespace {
/**
  Templated convenience wrapper which first attempts to resolve the
  handlerton using the data dictionary object's engine() string.

  @param thd    thread context
  @param ddt    Data dictionary object

  @return handlerton pointer for this object
    @retval handlerton pointer on success
    @retval nullptr on error
*/

template <typename DDT>
static handlerton *resolve_hton(THD *thd, const DDT &ddt) {
  plugin_ref pr = ha_resolve_by_name_raw(thd, lex_cstring_handle(ddt.engine()));
  if (pr) {
    return plugin_data<handlerton *>(pr);
  }
  return nullptr;
}

/**
  Covenience function for acquiring the schema and invoking a closure
  which uses the schema object.

  @param thd thread context
  @param key key to use when acquiring Schema object
  @param clos closure to invoke with the Schema object
  @return error status
    @retval false on success
    @retval true otherwise
 */
template <class AKT, class CLOS>
bool with_schema(THD *thd, const AKT &key, CLOS &&clos) {
  cache::Dictionary_client *dc = thd->dd_client();
  cache::Dictionary_client::Auto_releaser releaser(dc);

  const Schema *s = nullptr;
  if (dc->acquire(key, &s) || s == nullptr) {
    return true;
  }

  return clos(*s);
}

/**
  Predicate which returns true if an n-character prefix of two
  character ranges are equal.

  @param begin1 beginning of first range
  @param end1 end of first range
  @param begin2 beginning of second range
  @param end2 end of second range
  @param n number of characters to compare
  @param csi character set to use (defaults to system_charset_info)
  @return true if prefix compares equal, false otherwise
 */

template <class CHAR_IT>
bool equal_prefix_chars(CHAR_IT &&begin1, CHAR_IT &&end1, CHAR_IT &&begin2,
                        CHAR_IT &&end2, size_t n,
                        const CHARSET_INFO *csi = system_charset_info) {
  size_t char_count = 0;
  for (size_t rem_bytes = 0; char_count < n && begin1 < end1 && begin2 < end2;
       ++begin1, ++begin2) {
    if (*begin1 != *begin2) {
      return false;
    }
    if (rem_bytes == 0) {
      rem_bytes = my_mbcharlen(csi, static_cast<uchar>(*begin1));
      assert(rem_bytes > 0);
    }
    --rem_bytes;

    if (rem_bytes == 0) {
      ++char_count;
    }
  }
  return ((begin1 == end1 && begin2 == end2) || char_count == n);
}

/**
  Convenience function for comparing a prefix of the names of two DD objects.
  @param a first DD object
  @param b second DD object
  @param prefix_chars number characters in prefix to compare
  @return true if prefix compares equal, false otherwise
 */
template <class DDT>
bool equal_prefix_chars_name(const DDT &a, const DDT &b, size_t prefix_chars) {
  return equal_prefix_chars(a.name().begin(), a.name().end(), b.name().begin(),
                            b.name().end(), prefix_chars);
}

using DC = dd::cache::Dictionary_client;
using AR = dd::cache::Dictionary_client::Auto_releaser;

}  // namespace

namespace sdi {

bool store(THD *thd, const Table *tp) {
  const Table &t = ptr_as_cref(tp);
  handlerton *hton = resolve_hton(thd, t);

  return with_schema(thd, t.schema_id(), [&](const Schema &s) {
    dd::Sdi_type sdi = serialize(thd, t, s.name());
    if (sdi.empty()) {
      return checked_return(true);
    }
    DBUG_EXECUTE_IF("abort_rename_after_update", {
      my_error(ER_ERROR_ON_WRITE, MYF(0), "error inject", 42,
               "simulated write error");
      return true;
    });
    return checked_return(
        hton->sdi_set ? sdi_tablespace::store_tbl_sdi(thd, hton, sdi, t, s)
                      : sdi_file::store_tbl_sdi(sdi, t, s));
  });
}

bool store(THD *thd, const Tablespace *ts) {
  handlerton *hton = resolve_hton(thd, *ts);
  if (hton->sdi_set == nullptr) {
    return false;  // SDI api not supported
  }
  Sdi_type sdi = serialize(*ts);
  if (sdi.empty()) {
    return checked_return(true);
  }
  return checked_return(sdi_tablespace::store_tsp_sdi(hton, sdi, *ts));
}

bool drop(THD *thd, const Table *tp) {
  const Table &t = ptr_as_cref(tp);
  const handlerton &hton = ptr_as_cref(resolve_hton(thd, t));

  return with_schema(thd, t.schema_id(), [&](const Schema &s) {
    return checked_return(hton.sdi_delete
                              ? sdi_tablespace::drop_tbl_sdi(thd, hton, t, s)
                              : sdi_file::drop_tbl_sdi(t, s));
  });
}

bool drop_after_update(THD *thd, const Table *old_tp, const Table *new_tp) {
  const Table &old_t = ptr_as_cref(old_tp);
  const Table &new_t = ptr_as_cref(new_tp);

  if ((old_t.schema_id() == new_t.schema_id() &&
       equal_prefix_chars_name(old_t, new_t, sdi_file::FILENAME_PREFIX_CHARS))
      // Hack to avoid calling resolve_hton() during unit tests
      // reslove_hton() will crash in unit tests because the
      // plugin_LOCK mutex has not been initialized.
      // Reviewers: Please feel free to suggest alternative solutions.
      || old_t.engine() == "innodb") {
    return false;
  }

  const handlerton &old_hton = ptr_as_cref(resolve_hton(thd, old_t));
  if (old_hton.sdi_set) {
    return false;
  }

  return with_schema(thd, old_t.schema_id(), [&](const Schema &s) {
    return checked_return(sdi_file::drop_tbl_sdi(old_t, s));
  });
}

namespace {
template <typename DDT>
bool drop_all_impl(THD *thd, const DDT *tp) {
  const DDT &t = ptr_as_cref(tp);
  const handlerton &hton = ptr_as_cref(resolve_hton(thd, t));
  assert(hton.sdi_get != nullptr && hton.sdi_delete != nullptr);

  return checked_return(sdi_tablespace::drop_all_sdi(thd, hton, t));
}
}  // namespace

bool drop_all_for_table(THD *thd, const Table *tp) {
  return drop_all_impl(thd, tp);
}

bool drop_all_for_part(THD *thd, const Partition *pp) {
  return drop_all_impl(thd, pp);
}
}  // namespace sdi
}  // namespace dd
/** @{ */  // end of group sdi_api

/**
  @defgroup sdi_ut SDI Unit-testing API
  @ingroup sdi

  Special functions used by unit tests but which are not available in
  the normal api.

*/

/**
  @namespace sdi_unittest
  Namespace from dd_sdi-t unit-test. Also used to contain driver/hook
  functions only used by unit-testing.
*/

namespace sdi_unittest {

dd::String_type drv_s = "driver_schema";
dd::Sdi_wcontext drv_wctx(nullptr, &drv_s);

dd::Sdi_wcontext *get_wctx() { return &drv_wctx; }

dd::Sdi_rcontext drv_rctx(nullptr, 0, 0);
dd::Sdi_rcontext *get_rctx() { return &drv_rctx; }

bool equal_prefix_chars_driver(const dd::String_type &a,
                               const dd::String_type &b, size_t prefix) {
  return dd::equal_prefix_chars(a.begin(), a.end(), b.begin(), b.end(), prefix);
}
}  // namespace sdi_unittest

/** @} */  // End of group sdi_ut
