/*-------------------------------------------------------------------------

 *

 * nbtvalidate.c

 *    Opclass validator for btree.

 *

 * Portions Copyright (c) 1996-2025, PostgreSQL Global Development Group

 * Portions Copyright (c) 1994, Regents of the University of California

 *

 * IDENTIFICATION

 *    src/backend/access/nbtree/nbtvalidate.c

 *

 *-------------------------------------------------------------------------

 */

#include "postgres.h"

#include "access/amvalidate.h"

#include "access/htup_details.h"

#include "access/nbtree.h"

#include "access/xact.h"

#include "catalog/pg_am.h"

#include "catalog/pg_amop.h"

#include "catalog/pg_amproc.h"

#include "catalog/pg_opclass.h"

#include "catalog/pg_type.h"

#include "utils/builtins.h"

#include "utils/lsyscache.h"

#include "utils/regproc.h"

#include "utils/syscache.h"

/*

 * Validator for a btree opclass.

 *

 * Some of the checks done here cover the whole opfamily, and therefore are

 * redundant when checking each opclass in a family.  But they don't run long

 * enough to be much of a problem, so we accept the duplication rather than

 * complicate the amvalidate API.

 */

bool

btvalidate(Oid opclassoid)

{

  bool    result = true;

  HeapTuple classtup;

  Form_pg_opclass classform;

  Oid     opfamilyoid;

  Oid     opcintype;

  char     *opclassname;

  char     *opfamilyname;

  CatCList   *proclist,

         *oprlist;

  List     *grouplist;

  OpFamilyOpFuncGroup *opclassgroup;

  List     *familytypes;

  int     usefulgroups;

  int     i;

  ListCell   *lc;

  /* Fetch opclass information */

  classtup = SearchSysCache1(CLAOID, ObjectIdGetDatum(opclassoid));

  if (!HeapTupleIsValid(classtup))

    elog(ERROR, "cache lookup failed for operator class %u", opclassoid);

  classform = (Form_pg_opclass) GETSTRUCT(classtup);

  opfamilyoid = classform->opcfamily;

  opcintype = classform->opcintype;

  opclassname = NameStr(classform->opcname);

  /* Fetch opfamily information */

  opfamilyname = get_opfamily_name(opfamilyoid, false);

  /* Fetch all operators and support functions of the opfamily */

  oprlist = SearchSysCacheList1(AMOPSTRATEGY, ObjectIdGetDatum(opfamilyoid));

  proclist = SearchSysCacheList1(AMPROCNUM, ObjectIdGetDatum(opfamilyoid));

  /* Check individual support functions */

  for (i = 0; i < proclist->n_members; i++)

  {

    HeapTuple proctup = &proclist->members[i]->tuple;

    Form_pg_amproc procform = (Form_pg_amproc) GETSTRUCT(proctup);

    bool    ok;

    /* Check procedure numbers and function signatures */

    switch (procform->amprocnum)

    {

      case BTORDER_PROC:

        ok = check_amproc_signature(procform->amproc, INT4OID, true,

                      2, 2, procform->amproclefttype,

                      procform->amprocrighttype);

        break;

      case BTSORTSUPPORT_PROC:

        ok = check_amproc_signature(procform->amproc, VOIDOID, true,

                      1, 1, INTERNALOID);

        break;

      case BTINRANGE_PROC:

        ok = check_amproc_signature(procform->amproc, BOOLOID, true,

                      5, 5,

                      procform->amproclefttype,

                      procform->amproclefttype,

                      procform->amprocrighttype,

                      BOOLOID, BOOLOID);

        break;

      case BTEQUALIMAGE_PROC:

        ok = check_amproc_signature(procform->amproc, BOOLOID, true,

                      1, 1, OIDOID);

        break;

      case BTOPTIONS_PROC:

        ok = check_amoptsproc_signature(procform->amproc);

        break;

      case BTSKIPSUPPORT_PROC:

        ok = check_amproc_signature(procform->amproc, VOIDOID, true,

                      1, 1, INTERNALOID);

        break;

      default:

        ereport(INFO,

            (errcode(ERRCODE_INVALID_OBJECT_DEFINITION),

             errmsg("operator family \"%s\" of access method %s contains function %s with invalid support number %d",

                opfamilyname, "btree",

                format_procedure(procform->amproc),

                procform->amprocnum)));

        result = false;

        continue;   /* don't want additional message */

    }

    if (!ok)

    {

      ereport(INFO,

          (errcode(ERRCODE_INVALID_OBJECT_DEFINITION),

           errmsg("operator family \"%s\" of access method %s contains function %s with wrong signature for support number %d",

              opfamilyname, "btree",

              format_procedure(procform->amproc),

              procform->amprocnum)));

      result = false;

    }

  }

  /* Check individual operators */

  for (i = 0; i < oprlist->n_members; i++)

  {

    HeapTuple oprtup = &oprlist->members[i]->tuple;

    Form_pg_amop oprform = (Form_pg_amop) GETSTRUCT(oprtup);

    /* Check that only allowed strategy numbers exist */

    if (oprform->amopstrategy < 1 ||

      oprform->amopstrategy > BTMaxStrategyNumber)

    {

      ereport(INFO,

          (errcode(ERRCODE_INVALID_OBJECT_DEFINITION),

           errmsg("operator family \"%s\" of access method %s contains operator %s with invalid strategy number %d",

              opfamilyname, "btree",

              format_operator(oprform->amopopr),

              oprform->amopstrategy)));

      result = false;

    }

    /* btree doesn't support ORDER BY operators */

    if (oprform->amoppurpose != AMOP_SEARCH ||

      OidIsValid(oprform->amopsortfamily))

    {

      ereport(INFO,

          (errcode(ERRCODE_INVALID_OBJECT_DEFINITION),

           errmsg("operator family \"%s\" of access method %s contains invalid ORDER BY specification for operator %s",

              opfamilyname, "btree",

              format_operator(oprform->amopopr))));

      result = false;

    }

    /* Check operator signature --- same for all btree strategies */

    if (!check_amop_signature(oprform->amopopr, BOOLOID,

                  oprform->amoplefttype,

                  oprform->amoprighttype))

    {

      ereport(INFO,

          (errcode(ERRCODE_INVALID_OBJECT_DEFINITION),

           errmsg("operator family \"%s\" of access method %s contains operator %s with wrong signature",

              opfamilyname, "btree",

              format_operator(oprform->amopopr))));

      result = false;

    }

  }

  /* Now check for inconsistent groups of operators/functions */

  grouplist = identify_opfamily_groups(oprlist, proclist);

  usefulgroups = 0;

  opclassgroup = NULL;

  familytypes = NIL;

  foreach(lc, grouplist)

  {

    OpFamilyOpFuncGroup *thisgroup = (OpFamilyOpFuncGroup *) lfirst(lc);

    /*

     * It is possible for an in_range support function to have a RHS type

     * that is otherwise irrelevant to the opfamily --- for instance, SQL

     * requires the datetime_ops opclass to have range support with an

     * interval offset.  So, if this group appears to contain only an

     * in_range function, ignore it: it doesn't represent a pair of

     * supported types.

     */

    if (thisgroup->operatorset == 0 &&

      thisgroup->functionset == (1 << BTINRANGE_PROC))

      continue;

    /* Else count it as a relevant group */

    usefulgroups++;

    /* Remember the group exactly matching the test opclass */

    if (thisgroup->lefttype == opcintype &&

      thisgroup->righttype == opcintype)

      opclassgroup = thisgroup;

    /*

     * Identify all distinct data types handled in this opfamily.  This

     * implementation is O(N^2), but there aren't likely to be enough

     * types in the family for it to matter.

     */

    familytypes = list_append_unique_oid(familytypes, thisgroup->lefttype);

    familytypes = list_append_unique_oid(familytypes, thisgroup->righttype);

    /*

     * Complain if there seems to be an incomplete set of either operators

     * or support functions for this datatype pair.  The sortsupport,

     * in_range, and equalimage functions are considered optional.

     */

    if (thisgroup->operatorset !=

      ((1 << BTLessStrategyNumber) |

       (1 << BTLessEqualStrategyNumber) |

       (1 << BTEqualStrategyNumber) |

       (1 << BTGreaterEqualStrategyNumber) |

       (1 << BTGreaterStrategyNumber)))

    {

      ereport(INFO,

          (errcode(ERRCODE_INVALID_OBJECT_DEFINITION),

           errmsg("operator family \"%s\" of access method %s is missing operator(s) for types %s and %s",

              opfamilyname, "btree",

              format_type_be(thisgroup->lefttype),

              format_type_be(thisgroup->righttype))));

      result = false;

    }

    if ((thisgroup->functionset & (1 << BTORDER_PROC)) == 0)

    {

      ereport(INFO,

          (errcode(ERRCODE_INVALID_OBJECT_DEFINITION),

           errmsg("operator family \"%s\" of access method %s is missing support function for types %s and %s",

              opfamilyname, "btree",

              format_type_be(thisgroup->lefttype),

              format_type_be(thisgroup->righttype))));

      result = false;

    }

  }

  /* Check that the originally-named opclass is supported */

  /* (if group is there, we already checked it adequately above) */

  if (!opclassgroup)

  {

    ereport(INFO,

        (errcode(ERRCODE_INVALID_OBJECT_DEFINITION),

         errmsg("operator class \"%s\" of access method %s is missing operator(s)",

            opclassname, "btree")));

    result = false;

  }

  /*

   * Complain if the opfamily doesn't have entries for all possible

   * combinations of its supported datatypes.  While missing cross-type

   * operators are not fatal, they do limit the planner's ability to derive

   * additional qual clauses from equivalence classes, so it seems

   * reasonable to insist that all built-in btree opfamilies be complete.

   */

  if (usefulgroups != (list_length(familytypes) * list_length(familytypes)))

  {

    ereport(INFO,

        (errcode(ERRCODE_INVALID_OBJECT_DEFINITION),

         errmsg("operator family \"%s\" of access method %s is missing cross-type operator(s)",

            opfamilyname, "btree")));

    result = false;

  }

  ReleaseCatCacheList(proclist);

  ReleaseCatCacheList(oprlist);

  ReleaseSysCache(classtup);

  return result;

}

/*

 * Prechecking function for adding operators/functions to a btree opfamily.

 */

void

btadjustmembers(Oid opfamilyoid,

        Oid opclassoid,

        List *operators,

        List *functions)

{

  Oid     opcintype;

  ListCell   *lc;

  /*

   * Btree operators and comparison support functions are always "loose"

   * members of the opfamily if they are cross-type.  If they are not

   * cross-type, we prefer to tie them to the appropriate opclass ... but if

   * the user hasn't created one, we can't do that, and must fall back to

   * using the opfamily dependency.  (We mustn't force creation of an

   * opclass in such a case, as leaving an incomplete opclass laying about

   * would be bad.  Throwing an error is another undesirable alternative.)

   *

   * This behavior results in a bit of a dump/reload hazard, in that the

   * order of restoring objects could affect what dependencies we end up

   * with.  pg_dump's existing behavior will preserve the dependency choices

   * in most cases, but not if a cross-type operator has been bound tightly

   * into an opclass.  That's a mistake anyway, so silently "fixing" it

   * isn't awful.

   *

   * Optional support functions are always "loose" family members.

   *

   * To avoid repeated lookups, we remember the most recently used opclass's

   * input type.

   */

  if (OidIsValid(opclassoid))

  {

    /* During CREATE OPERATOR CLASS, need CCI to see the pg_opclass row */

    CommandCounterIncrement();

    opcintype = get_opclass_input_type(opclassoid);

  }

  else

    opcintype = InvalidOid;

  /*

   * We handle operators and support functions almost identically, so rather

   * than duplicate this code block, just join the lists.

   */

  foreach(lc, list_concat_copy(operators, functions))

  {

    OpFamilyMember *op = (OpFamilyMember *) lfirst(lc);

    if (op->is_func && op->number != BTORDER_PROC)

    {

      /* Optional support proc, so always a soft family dependency */

      op->ref_is_hard = false;

      op->ref_is_family = true;

      op->refobjid = opfamilyoid;

    }

    else if (op->lefttype != op->righttype)

    {

      /* Cross-type, so always a soft family dependency */

      op->ref_is_hard = false;

      op->ref_is_family = true;

      op->refobjid = opfamilyoid;

    }

    else

    {

      /* Not cross-type; is there a suitable opclass? */

      if (op->lefttype != opcintype)

      {

        /* Avoid repeating this expensive lookup, even if it fails */

        opcintype = op->lefttype;

        opclassoid = opclass_for_family_datatype(BTREE_AM_OID,

                             opfamilyoid,

                             opcintype);

      }

      if (OidIsValid(opclassoid))

      {

        /* Hard dependency on opclass */

        op->ref_is_hard = true;

        op->ref_is_family = false;

        op->refobjid = opclassoid;

      }

      else

      {

        /* We're stuck, so make a soft dependency on the opfamily */

        op->ref_is_hard = false;

        op->ref_is_family = true;

        op->refobjid = opfamilyoid;

      }

    }

  }

}