polardbxengine/sql/dd/impl/sdi.cc

/* Copyright (c) 2015, 2019, Oracle and/or its affiliates. All rights reserved.

   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.

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   documentation.  The authors of MySQL hereby grant you an additional
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   This program is distributed in the hope that it will be useful,
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   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
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   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 <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/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)) {
    DBUG_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 MY_ATTRIBUTE((unused)),
    dd::Object_id id MY_ATTRIBUTE((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_;
  }
  DBUG_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) {
  DBUG_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);
}

template <class Dd_type>
bool generic_deserialize(
    THD *thd, const Sdi_type &sdi,
    const String_type &object_type_name MY_ATTRIBUTE((unused)), Dd_type *dst,
    String_type *schema_name_from_sdi = nullptr) {
  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 (doc.HasMember("mysqld_version_id")) {
    RJ_Value &mysqld_version_id = doc["mysqld_version_id"];
    DBUG_ASSERT(mysqld_version_id.IsUint64());
    if (mysqld_version_id.GetUint64() > std::uint64_t(MYSQL_VERSION_ID)) {
      // Cannot deserialize SDIs from newer versions. Required?
      my_error(ER_IMP_INCOMPATIBLE_MYSQLD_VERSION, MYF(0),
               mysqld_version_id.GetUint64(), std::uint64_t(MYSQL_VERSION_ID));
      return true;
    }
  } else {
    DBUG_ASSERT(false);
  }

  DBUG_ASSERT(doc.HasMember("dd_version"));
  RJ_Value &dd_version_val = doc["dd_version"];
  DBUG_ASSERT(dd_version_val.IsUint());
  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;
  }

  DBUG_ASSERT(doc.HasMember("sdi_version"));
  RJ_Value &sdi_version_val = doc["sdi_version"];
  DBUG_ASSERT(sdi_version_val.IsUint64());
  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;
  }

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

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

  Sdi_rcontext rctx(thd, dd_version, sdi_version_);
  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;
}

bool deserialize(THD *thd, const Sdi_type &sdi, Table *dst_table,
                 String_type *deser_schema_name) {
  return generic_deserialize(thd, sdi, "Table", dst_table, deser_schema_name);
}

bool deserialize(THD *thd, const Sdi_type &sdi, Tablespace *dst_tablespace) {
  return generic_deserialize(thd, sdi, "Tablespace", dst_tablespace);
}

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

  @param thd
  @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
  @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));
      DBUG_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 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