/*-------------------------------------------------------------------------
 *
 * copy.c--
 *
 * Copyright (c) 1994, Regents of the University of California
 *
 *
 * IDENTIFICATION
 *    $Header: /cvsroot/pgsql/src/backend/commands/copy.c,v 1.26 1997/08/19 04:43:28 vadim Exp $
 *
 *-------------------------------------------------------------------------
 */

#include <string.h>
#include <unistd.h>

#include <postgres.h>

#include <access/heapam.h>
#include <tcop/dest.h>
#include <fmgr.h>
#include <miscadmin.h>
#include <utils/builtins.h>
#include <utils/acl.h>
#include <sys/stat.h>
#include <catalog/pg_index.h>
#include <utils/syscache.h>
#include <utils/memutils.h>
#include <executor/executor.h>
#include <access/transam.h>
#include <catalog/index.h>
#include <access/genam.h>
#include <catalog/pg_type.h>
#include <catalog/catname.h>
#include <catalog/pg_user.h>
#include <commands/copy.h>
#include <storage/fd.h>

#define ISOCTAL(c) (((c) >= '0') && ((c) <= '7'))
#define VALUE(c) ((c) - '0')


/* non-export function prototypes */
static void CopyTo(Relation rel, bool binary, bool oids, FILE *fp, char *delim);
static void CopyFrom(Relation rel, bool binary, bool oids, FILE *fp, char *delim);
static Oid GetOutputFunction(Oid type);
static Oid GetTypeElement(Oid type);
static Oid GetInputFunction(Oid type);
static Oid IsTypeByVal(Oid type);
static void GetIndexRelations(Oid main_relation_oid,
                              int *n_indices,
                              Relation **index_rels);
#ifdef COPY_PATCH
static void CopyReadNewline(FILE *fp, int *newline);
static char *CopyReadAttribute(FILE *fp, bool *isnull, char *delim, int *newline);
#else
static char *CopyReadAttribute(FILE *fp, bool *isnull, char *delim);
#endif
static void CopyAttributeOut(FILE *fp, char *string, char *delim);
static int CountTuples(Relation relation);

extern FILE *Pfout, *Pfin;

#ifdef COPY_DEBUG
static int lineno;
#endif
 
/*
 *   DoCopy executes a the SQL COPY statement.
 */

void
DoCopy(char *relname, bool binary, bool oids, bool from, bool pipe, 
       char *filename, char *delim) {
/*----------------------------------------------------------------------------
  Either unload or reload contents of class <relname>, depending on <from>.

  If <pipe> is false, transfer is between the class and the file named
  <filename>.  Otherwise, transfer is between the class and our regular
  input/output stream.  The latter could be either stdin/stdout or a 
  socket, depending on whether we're running under Postmaster control.

  Iff <binary>, unload or reload in the binary format, as opposed to the
  more wasteful but more robust and portable text format.  

  If in the text format, delimit columns with delimiter <delim>.  

  When loading in the text format from an input stream (as opposed to
  a file), recognize a "." on a line by itself as EOF.  Also recognize
  a stream EOF.  When unloading in the text format to an output stream,
  write a "." on a line by itself at the end of the data.

  Iff <oids>, unload or reload the format that includes OID information.

  Do not allow a Postgres user without superuser privilege to read from
  or write to a file. 

  Do not allow the copy if user doesn't have proper permission to access
  the class.
----------------------------------------------------------------------------*/

    FILE *fp;
    Relation rel;
    extern char *UserName;    /* defined in global.c */
    const AclMode required_access = from ? ACL_WR : ACL_RD;
    int result;

    rel = heap_openr(relname);
    if (rel == NULL) elog(WARN, "COPY command failed.  Class %s "
                          "does not exist.", relname);

    result = pg_aclcheck(relname, UserName, required_access);
    if(result != ACLCHECK_OK)
        elog(WARN, "%s: %s", relname, aclcheck_error_strings[result]);
        /* Above should not return */
    else if (!superuser() && !pipe)
        elog(WARN, "You must have Postgres superuser privilege to do a COPY "
             "directly to or from a file.  Anyone can COPY to stdout or "
             "from stdin.  Psql's \\copy command also works for anyone.");
        /* Above should not return. */
    else {
        if (from) {  /* copy from file to database */
	    if ( rel->rd_rel->relkind == RELKIND_SEQUENCE )
	    	elog (WARN, "You can't change sequence relation %s", relname);
            if (pipe) {
                if (IsUnderPostmaster) {
                    ReceiveCopyBegin();
                    fp = Pfin;
                } else fp = stdin;
            } else {
                fp = AllocateFile(filename, "r");
                if (fp == NULL) 
                    elog(WARN, "COPY command, running in backend with "
                         "effective uid %d, could not open file '%s' for "
                         "reading.  Errno = %s (%d).", 
                         geteuid(), filename, strerror(errno), errno);
                    /* Above should not return */
            }
            CopyFrom(rel, binary, oids, fp, delim);
        } else {  /* copy from database to file */
            if (pipe) {
                if (IsUnderPostmaster) {
                    SendCopyBegin();
                    fp = Pfout;
                } else fp = stdout;
            } else {
                mode_t oumask;  /* Pre-existing umask value */
                oumask =  umask((mode_t) 0);
                fp = AllocateFile(filename, "w");
                umask(oumask);
                if (fp == NULL) 
                    elog(WARN, "COPY command, running in backend with "
                         "effective uid %d, could not open file '%s' for "
                         "writing.  Errno = %s (%d).", 
                         geteuid(), filename, strerror(errno), errno);
                    /* Above should not return */
            }
            CopyTo(rel, binary, oids, fp, delim);
        }
        if (!pipe)
		FreeFile(fp);
        else if (!from && !binary) {
            fputs("\\.\n", fp);
            if (IsUnderPostmaster) fflush(Pfout);
        }
    }
}



static void
CopyTo(Relation rel, bool binary, bool oids, FILE *fp, char *delim)
{
    HeapTuple tuple;
    HeapScanDesc scandesc;
    
    int32 attr_count, i;
    AttributeTupleForm *attr;
    func_ptr *out_functions;
    int dummy;
    Oid out_func_oid;
    Oid *elements;
    Datum value;
    bool isnull;  /* The attribute we are copying is null */
    char *nulls;
        /* <nulls> is a (dynamically allocated) array with one character
           per attribute in the instance being copied.  nulls[I-1] is
           'n' if Attribute Number I is null, and ' ' otherwise.

           <nulls> is meaningful only if we are doing a binary copy.
           */
    char *string;
    int32 ntuples;
    TupleDesc tupDesc;
    
    scandesc = heap_beginscan(rel, 0, NULL, 0, NULL);

    attr_count = rel->rd_att->natts;
    attr = rel->rd_att->attrs;
    tupDesc = rel->rd_att;

    if (!binary) {
        out_functions = (func_ptr *) palloc(attr_count * sizeof(func_ptr));
        elements = (Oid *) palloc(attr_count * sizeof(Oid));
        for (i = 0; i < attr_count; i++) {
            out_func_oid = (Oid) GetOutputFunction(attr[i]->atttypid);
            fmgr_info(out_func_oid, &out_functions[i], &dummy);
            elements[i] = GetTypeElement(attr[i]->atttypid);
        }
        nulls = NULL;  /* meaningless, but compiler doesn't know that */
    }else {
        elements = NULL;
        out_functions = NULL;
        nulls = (char *) palloc(attr_count);
        for (i = 0; i < attr_count; i++) nulls[i] = ' ';
        
        /* XXX expensive */
        
        ntuples = CountTuples(rel);
        fwrite(&ntuples, sizeof(int32), 1, fp);
    }
    
    for (tuple = heap_getnext(scandesc, 0, NULL);
         tuple != NULL; 
         tuple = heap_getnext(scandesc, 0, NULL)) {

        if (oids && !binary) {
                fputs(oidout(tuple->t_oid),fp);
                fputc(delim[0], fp);
        }
        
        for (i = 0; i < attr_count; i++) {
            value = (Datum) 
                heap_getattr(tuple, InvalidBuffer, i+1, tupDesc, &isnull);
            if (!binary) {
                if (!isnull) {
                    string = (char *) (out_functions[i]) (value, elements[i]);
                    CopyAttributeOut(fp, string, delim);
                    pfree(string);
                }
                else
                    fputs("\\N", fp);   /* null indicator */

                if (i == attr_count - 1) {
                    fputc('\n', fp);
                }else {
                    /* when copying out, only use the first char of the delim
                       string */
                    fputc(delim[0], fp);
                }
            }else {
                /*
                 * only interesting thing heap_getattr tells us in this case
                 * is if we have a null attribute or not.
                 */
                if (isnull) nulls[i] = 'n';
            }
        }
        
        if (binary) {
            int32 null_ct = 0, length;
            
            for (i = 0; i < attr_count; i++) {
                if (nulls[i] == 'n') null_ct++;
            }
            
            length = tuple->t_len - tuple->t_hoff;
            fwrite(&length, sizeof(int32), 1, fp);
            if (oids)
                fwrite((char *) &tuple->t_oid, sizeof(int32), 1, fp);

            fwrite(&null_ct, sizeof(int32), 1, fp);
            if (null_ct > 0) {
                for (i = 0; i < attr_count; i++) {
                    if (nulls[i] == 'n') {
                        fwrite(&i, sizeof(int32), 1, fp);
                        nulls[i] = ' ';
                    }
                }
            }
            fwrite((char *) tuple + tuple->t_hoff, length, 1, fp);
        }
    }
    
    heap_endscan(scandesc);
    if (binary) {
        pfree(nulls);
    }else {
        pfree(out_functions);
        pfree(elements);
    }
    
    heap_close(rel);
}

static void
CopyFrom(Relation rel, bool binary, bool oids, FILE *fp, char *delim)
{
    HeapTuple tuple;
    AttrNumber attr_count;
    AttributeTupleForm *attr;
    func_ptr *in_functions;
    int i, dummy;
    Oid in_func_oid;
    Datum *values;
    char *nulls, *index_nulls;
    bool *byval;
    bool isnull;
    bool has_index;
    int done = 0;
    char *string = NULL, *ptr;
    Relation *index_rels;
    int32 len, null_ct, null_id;
    int32 ntuples, tuples_read = 0;
    bool reading_to_eof = true;
    Oid *elements;
    FuncIndexInfo *finfo, **finfoP = NULL;
    TupleDesc *itupdescArr;
    HeapTuple pgIndexTup;
    IndexTupleForm *pgIndexP = NULL;
    int *indexNatts = NULL;
    char *predString;
    Node **indexPred = NULL;
    TupleDesc rtupdesc;
    ExprContext *econtext = NULL;
#ifndef OMIT_PARTIAL_INDEX
    TupleTable tupleTable;
    TupleTableSlot *slot = NULL;
#endif
    int natts;
    AttrNumber *attnumP;
    Datum *idatum;
    int n_indices;
    InsertIndexResult indexRes;
    TupleDesc tupDesc;
    Oid loaded_oid;
    
    tupDesc = RelationGetTupleDescriptor(rel);
    attr = tupDesc->attrs;
    attr_count = tupDesc->natts;

    has_index = false;
    
    /*
     *  This may be a scalar or a functional index.  We initialize all
     *  kinds of arrays here to avoid doing extra work at every tuple
     *  copy.
     */
    
    if (rel->rd_rel->relhasindex) {
        GetIndexRelations(rel->rd_id, &n_indices, &index_rels);
        if (n_indices > 0) {
            has_index = true;
            itupdescArr = 
                (TupleDesc *)palloc(n_indices * sizeof(TupleDesc));
            pgIndexP =
                (IndexTupleForm *)palloc(n_indices * sizeof(IndexTupleForm));
            indexNatts = (int *) palloc(n_indices * sizeof(int));
            finfo = (FuncIndexInfo *) palloc(n_indices * sizeof(FuncIndexInfo));
            finfoP = (FuncIndexInfo **) palloc(n_indices * sizeof(FuncIndexInfo *));
            indexPred = (Node **) palloc(n_indices * sizeof(Node*));
            econtext = NULL;
            for (i = 0; i < n_indices; i++) {
                itupdescArr[i] = RelationGetTupleDescriptor(index_rels[i]);
                pgIndexTup =
                    SearchSysCacheTuple(INDEXRELID,
                                        ObjectIdGetDatum(index_rels[i]->rd_id),
                                        0,0,0);
                Assert(pgIndexTup);
                pgIndexP[i] = (IndexTupleForm)GETSTRUCT(pgIndexTup);
                for (attnumP = &(pgIndexP[i]->indkey[0]), natts = 0;
                     *attnumP != InvalidAttrNumber;
                     attnumP++, natts++);
                if (pgIndexP[i]->indproc != InvalidOid) {
                    FIgetnArgs(&finfo[i]) = natts;
                    natts = 1;
                    FIgetProcOid(&finfo[i]) = pgIndexP[i]->indproc;
                    *(FIgetname(&finfo[i])) = '\0';
                    finfoP[i] = &finfo[i];
                } else
                    finfoP[i] = (FuncIndexInfo *) NULL;
                indexNatts[i] = natts;
                if (VARSIZE(&pgIndexP[i]->indpred) != 0) {
                    predString = fmgr(F_TEXTOUT, &pgIndexP[i]->indpred);
                    indexPred[i] = stringToNode(predString);
                    pfree(predString);
                    /* make dummy ExprContext for use by ExecQual */
                    if (econtext == NULL) {
#ifndef OMIT_PARTIAL_INDEX
                        tupleTable = ExecCreateTupleTable(1); 
                        slot =   ExecAllocTableSlot(tupleTable);
                        econtext = makeNode(ExprContext);
                        econtext->ecxt_scantuple = slot;
                        rtupdesc = RelationGetTupleDescriptor(rel);
                        slot->ttc_tupleDescriptor = rtupdesc;
                        /*
                         * There's no buffer associated with heap tuples here,
                         * so I set the slot's buffer to NULL.  Currently, it
                         * appears that the only way a buffer could be needed
                         * would be if the partial index predicate referred to
                         * the "lock" system attribute.  If it did, then
                         * heap_getattr would call HeapTupleGetRuleLock, which
                         * uses the buffer's descriptor to get the relation id.
                         * Rather than try to fix this, I'll just disallow
                         * partial indexes on "lock", which wouldn't be useful
                         * anyway. --Nels, Nov '92
                         */
                        /* SetSlotBuffer(slot, (Buffer) NULL); */
                        /* SetSlotShouldFree(slot, false); */
                        slot->ttc_buffer = (Buffer)NULL;
                        slot->ttc_shouldFree = false;
#endif /* OMIT_PARTIAL_INDEX */    
                    }
                } else {
                    indexPred[i] = NULL;
                }
            }
        }
    }
    
    if (!binary)
        {
            in_functions = (func_ptr *) palloc(attr_count * sizeof(func_ptr));
            elements = (Oid *) palloc(attr_count * sizeof(Oid));
            for (i = 0; i < attr_count; i++)
                {
                    in_func_oid = (Oid) GetInputFunction(attr[i]->atttypid);
                    fmgr_info(in_func_oid, &in_functions[i], &dummy);
                    elements[i] = GetTypeElement(attr[i]->atttypid);
                }
        }
    else
        {
                in_functions = NULL;
                elements = NULL;
            fread(&ntuples, sizeof(int32), 1, fp);
            if (ntuples != 0) reading_to_eof = false;
        }
    
    values       = (Datum *) palloc(sizeof(Datum) * attr_count);
    nulls        = (char *) palloc(attr_count);
    index_nulls  = (char *) palloc(attr_count);
    idatum       = (Datum *) palloc(sizeof(Datum) * attr_count);
    byval        = (bool *) palloc(attr_count * sizeof(bool));
    
    for (i = 0; i < attr_count; i++) {
        nulls[i] = ' ';
        index_nulls[i] = ' ';
        byval[i] = (bool) IsTypeByVal(attr[i]->atttypid);
    }
    
#ifdef COPY_DEBUG
    lineno = 0;
#endif
    while (!done) {
        if (!binary) {
#ifdef COPY_PATCH
	    int newline = 0;
#endif
#ifdef COPY_DEBUG
	    lineno++;
	    elog(DEBUG, "line %d", lineno);
#endif
            if (oids) {
#ifdef COPY_PATCH
		string = CopyReadAttribute(fp, &isnull, delim, &newline);
#else
                string = CopyReadAttribute(fp, &isnull, delim);
#endif
                if (string == NULL)
                    done = 1;
                else {
                    loaded_oid = oidin(string);
                    if (loaded_oid < BootstrapObjectIdData)
                        elog(WARN, "COPY TEXT: Invalid Oid");
                }
            }
            for (i = 0; i < attr_count && !done; i++) {
#ifdef COPY_PATCH
		string = CopyReadAttribute(fp, &isnull, delim, &newline);
#else
                string = CopyReadAttribute(fp, &isnull, delim);
#endif
                if (isnull) {
                    values[i] = PointerGetDatum(NULL);
                    nulls[i] = 'n';
                }else if (string == NULL) {
                    done = 1;
                }else {
                    values[i] =
                        (Datum)(in_functions[i])(string,
                                                 elements[i],
                                                 attr[i]->attlen);
                    /*
                     * Sanity check - by reference attributes cannot return
                     * NULL
                     */
                    if (!PointerIsValid(values[i]) &&
                        !(rel->rd_att->attrs[i]->attbyval)) {
#ifdef COPY_DEBUG
			elog(WARN,
			     "copy from: line %d - Bad file format", lineno);
#else
                        elog(WARN, "copy from: Bad file format");
#endif
                    }
                }
            }
#ifdef COPY_PATCH
	    if (!done) {
		CopyReadNewline(fp, &newline);
	    }
#endif
        }else { /* binary */
            fread(&len, sizeof(int32), 1, fp);
            if (feof(fp)) {
                done = 1;
            }else {
                if (oids) {
                    fread(&loaded_oid, sizeof(int32), 1, fp);
                    if (loaded_oid < BootstrapObjectIdData)
                        elog(WARN, "COPY BINARY: Invalid Oid");
                }
                fread(&null_ct, sizeof(int32), 1, fp);
                if (null_ct > 0) {
                    for (i = 0; i < null_ct; i++) {
                        fread(&null_id, sizeof(int32), 1, fp);
                        nulls[null_id] = 'n';
                    }
                }
                
                string = (char *) palloc(len);
                fread(string, len, 1, fp);
                
                ptr = string;
                
                for (i = 0; i < attr_count; i++) {
                    if (byval[i] && nulls[i] != 'n') {
                        
                        switch(attr[i]->attlen) {
                        case sizeof(char):
                            values[i] = (Datum) *(unsigned char *) ptr;
                            ptr += sizeof(char);
                            break;
                        case sizeof(short):
                            ptr = (char *) SHORTALIGN(ptr);
                            values[i] = (Datum) *(unsigned short *) ptr; 
                            ptr += sizeof(short);
                            break;
                        case sizeof(int32):
                            ptr = (char *) INTALIGN(ptr);
                            values[i] = (Datum) *(uint32 *) ptr;
                            ptr += sizeof(int32);
                            break;
                        default:
                            elog(WARN, "COPY BINARY: impossible size!");
                            break;
                        }
                    }else if (nulls[i] != 'n') {
                        switch (attr[i]->attlen) {
                        case -1:
                            if (attr[i]->attalign == 'd') 
                                ptr = (char *)DOUBLEALIGN(ptr);
                            else
                                ptr = (char *)INTALIGN(ptr);
                            values[i] = (Datum) ptr;
                            ptr += * (uint32 *) ptr;
                            break;
                        case sizeof(char):
                            values[i] = (Datum)ptr;
                            ptr += attr[i]->attlen;
                            break;
                        case sizeof(short):
                            ptr = (char*)SHORTALIGN(ptr);
                            values[i] = (Datum)ptr;
                            ptr += attr[i]->attlen;
                            break;
                        case sizeof(int32):
                            ptr = (char*)INTALIGN(ptr);
                            values[i] = (Datum)ptr;
                            ptr += attr[i]->attlen;
                            break;
                        default:
                            if (attr[i]->attalign == 'd')
                                ptr = (char *)DOUBLEALIGN(ptr);
                            else 
                                ptr = (char *)LONGALIGN(ptr);
                            values[i] = (Datum) ptr;
                            ptr += attr[i]->attlen;
                        }
                    }
                }
            }
        }
        if (done) continue;

	/*
	 * Does it have any sence ? - vadim 12/14/96
	 *                    
        tupDesc = CreateTupleDesc(attr_count, attr);
	 */
        tuple = heap_formtuple(tupDesc, values, nulls);
        if (oids)
            tuple->t_oid = loaded_oid;

	/* ----------------
	 * Check the constraints of a tuple
	 * ----------------
	 */
	
	if (rel->rd_att->constr && rel->rd_att->constr->has_not_null)
	  {
	    int attrChk;
	    for (attrChk = 1; attrChk <= rel->rd_att->natts; attrChk++) {
	      if (rel->rd_att->attrs[attrChk-1]->attnotnull && heap_attisnull(tuple,attrChk))
		elog(WARN,"CopyFrom:  Fail to add null value in not null attribute %s",
		     rel->rd_att->attrs[attrChk-1]->attname.data);
	    }
	  }
	
        heap_insert(rel, tuple);
            
        if (has_index) {
            for (i = 0; i < n_indices; i++) {
                if (indexPred[i] != NULL) {
#ifndef OMIT_PARTIAL_INDEX
                    /* if tuple doesn't satisfy predicate,
                     * don't update index
                     */
                    slot->val = tuple;
                    /*SetSlotContents(slot, tuple); */
                    if (ExecQual((List*)indexPred[i], econtext) == false)
                        continue;
#endif /* OMIT_PARTIAL_INDEX */         
                }
                FormIndexDatum(indexNatts[i],
                               (AttrNumber *)&(pgIndexP[i]->indkey[0]),
                               tuple,
                               tupDesc,
                               InvalidBuffer,
                               idatum,
                               index_nulls,
                               finfoP[i]);
                indexRes = index_insert(index_rels[i], idatum, index_nulls,
                                        &(tuple->t_ctid), rel);
                if (indexRes) pfree(indexRes);
            }
        }
            
        if (binary) pfree(string);
            
        for (i = 0; i < attr_count; i++) {
            if (!byval[i] && nulls[i] != 'n') {
                if (!binary) pfree((void*)values[i]);
            }else if (nulls[i] == 'n') {
                nulls[i] = ' ';
            }
        }
            
        pfree(tuple);
        tuples_read++;
            
        if (!reading_to_eof && ntuples == tuples_read) done = true;
    }
    pfree(values);
    if (!binary) pfree(in_functions);
    pfree(nulls);
    pfree(byval);
    heap_close(rel);
}



static Oid
GetOutputFunction(Oid type)
{
    HeapTuple    typeTuple;
    
    typeTuple = SearchSysCacheTuple(TYPOID,
                                    ObjectIdGetDatum(type),
                                    0,0,0);
    
    if (HeapTupleIsValid(typeTuple))
        return((int) ((TypeTupleForm) GETSTRUCT(typeTuple))->typoutput);
    
    elog(WARN, "GetOutputFunction: Cache lookup of type %d failed", type);
    return(InvalidOid);
}

static Oid
GetTypeElement(Oid type)
{
    HeapTuple    typeTuple;
    
    typeTuple = SearchSysCacheTuple(TYPOID,
                                    ObjectIdGetDatum(type),
                                    0,0,0);

    
    if (HeapTupleIsValid(typeTuple))
        return((int) ((TypeTupleForm) GETSTRUCT(typeTuple))->typelem);
    
    elog(WARN, "GetOutputFunction: Cache lookup of type %d failed", type);
    return(InvalidOid);
}

static Oid
GetInputFunction(Oid type)
{
    HeapTuple    typeTuple;
    
    typeTuple = SearchSysCacheTuple(TYPOID,
                                    ObjectIdGetDatum(type),
                                    0,0,0);
    
    if (HeapTupleIsValid(typeTuple))
        return((int) ((TypeTupleForm) GETSTRUCT(typeTuple))->typinput);
    
    elog(WARN, "GetInputFunction: Cache lookup of type %d failed", type);
    return(InvalidOid);
}

static Oid
IsTypeByVal(Oid type)
{
    HeapTuple    typeTuple;
    
    typeTuple = SearchSysCacheTuple(TYPOID,
                                    ObjectIdGetDatum(type),
                                    0,0,0);
    
    if (HeapTupleIsValid(typeTuple))
        return((int) ((TypeTupleForm) GETSTRUCT(typeTuple))->typbyval);
    
    elog(WARN, "GetInputFunction: Cache lookup of type %d failed", type);
    
    return(InvalidOid);
}

/* 
 * Given the OID of a relation, return an array of index relation descriptors
 * and the number of index relations.  These relation descriptors are open
 * using heap_open().
 *
 * Space for the array itself is palloc'ed.
 */

typedef struct rel_list {
    Oid index_rel_oid;
    struct rel_list *next;
} RelationList;

static void
GetIndexRelations(Oid main_relation_oid,
                  int *n_indices,
                  Relation **index_rels)
{
    RelationList *head, *scan;
    Relation pg_index_rel;
    HeapScanDesc scandesc;
    Oid index_relation_oid;
    HeapTuple tuple;
    TupleDesc tupDesc;
    int i;
    bool isnull;
    
    pg_index_rel = heap_openr(IndexRelationName);
    scandesc = heap_beginscan(pg_index_rel, 0, NULL, 0, NULL);
    tupDesc = RelationGetTupleDescriptor(pg_index_rel);
    
    *n_indices = 0;
    
    head = (RelationList *) palloc(sizeof(RelationList));
    scan = head;
    head->next = NULL;
    
    for (tuple = heap_getnext(scandesc, 0, NULL);
         tuple != NULL; 
         tuple = heap_getnext(scandesc, 0, NULL)) {
        
        index_relation_oid =
            (Oid) DatumGetInt32(heap_getattr(tuple, InvalidBuffer, 2,
                                             tupDesc, &isnull));
        if (index_relation_oid == main_relation_oid) {
            scan->index_rel_oid =
                (Oid) DatumGetInt32(heap_getattr(tuple, InvalidBuffer,
                                                 Anum_pg_index_indexrelid,
                                                 tupDesc, &isnull));
            (*n_indices)++;
            scan->next = (RelationList *) palloc(sizeof(RelationList));
            scan = scan->next;
        }
    }
    
    heap_endscan(scandesc);
    heap_close(pg_index_rel);
    
    /* We cannot trust to relhasindex of the main_relation now, so... */
    if ( *n_indices == 0 )
      return;

    *index_rels = (Relation *) palloc(*n_indices * sizeof(Relation));
    
    for (i = 0, scan = head; i < *n_indices; i++, scan = scan->next) {
        (*index_rels)[i] = index_open(scan->index_rel_oid);
    }
    
    for (i = 0, scan = head; i < *n_indices + 1; i++) {
        scan = head->next;
        pfree(head);
        head = scan;
    }
}

#define EXT_ATTLEN 5*8192

/*
   returns 1 is c is in s
*/
static bool
inString(char c, char* s)
{
    int i;

    if (s) {
        i = 0;
        while (s[i] != '\0') {
            if (s[i] == c)
                return 1;
            i++;
        }
    }
    return 0;
}

#ifdef COPY_PATCH
/*
 * Reads input from fp until an end of line is seen.
 */

void
CopyReadNewline(FILE *fp, int *newline)
{
    if (!*newline) {
#ifdef COPY_DEBUG
	elog(NOTICE, "CopyReadNewline: line %d - extra fields ignored",
	     lineno);
#else
	elog(NOTICE, "CopyReadNewline: line - extra fields ignored");
#endif
	while (!feof(fp) && (getc(fp) != '\n'));
    }
    *newline = 0;
}
#endif

/*
 * Reads input from fp until eof is seen.  If we are reading from standard
 * input, AND we see a dot on a line by itself (a dot followed immediately
 * by a newline), we exit as if we saw eof.  This is so that copy pipelines
 * can be used as standard input.
 */

static char *
#ifdef COPY_PATCH
CopyReadAttribute(FILE *fp, bool *isnull, char *delim, int *newline)
#else
CopyReadAttribute(FILE *fp, bool *isnull, char *delim)
#endif
{
    static char attribute[EXT_ATTLEN];
    char c;
    int done = 0;
    int i = 0;
    
#ifdef COPY_PATCH
    /* if last delimiter was a newline return a NULL attribute */
    if (*newline) {
	*isnull = (bool) true;
	return(NULL);
    }
#endif

    *isnull = (bool) false;     /* set default */
    if (feof(fp))
        return(NULL);
    
    while (!done) {
        c = getc(fp);
            
        if (feof(fp))
            return(NULL);
        else if (c == '\\') {
            c = getc(fp);
            if (feof(fp))
                return(NULL);
            switch (c) {
              case '0':
              case '1':
              case '2':
              case '3':
              case '4':
              case '5':
              case '6':
              case '7': {
                int val;
                val = VALUE(c);
                c = getc(fp);
                if (ISOCTAL(c)) {
                    val = (val<<3) + VALUE(c);
                    c = getc(fp);
                    if (ISOCTAL(c)) {
                        val = (val<<3) + VALUE(c);
                    } else {
                        if (feof(fp))
                            return(NULL);
                        ungetc(c, fp);
                    }
                } else {
                    if (feof(fp))
                        return(NULL);
                    ungetc(c, fp);
                }
                c = val & 0377;
              }
                break;
              case 'b':
                c = '\b';
                break;
              case 'f':
                c = '\f';
                break;
              case 'n':
                c = '\n';
                break;
              case 'r':
                c = '\r';
                break;
              case 't':
                c = '\t';
                break;
              case 'v':
                c = '\v';
                break;
              case 'N':
                attribute[0] = '\0'; /* just to be safe */
                *isnull = (bool) true;
                break;
              case '.':
                c = getc(fp);
                if (c != '\n')
                    elog(WARN, "CopyReadAttribute - end of record marker corrupted");
                return(NULL);
                break;
            }
        }else if (inString(c,delim) || c == '\n') {
#ifdef COPY_PATCH
	    if (c == '\n') {
		*newline = 1;
	    }
#endif
            done = 1;
        }
        if (!done) attribute[i++] = c;
        if (i == EXT_ATTLEN - 1)
            elog(WARN, "CopyReadAttribute - attribute length too long");
    }
    attribute[i] = '\0';
    return(&attribute[0]);
}

static void
CopyAttributeOut(FILE *fp, char *string, char *delim)
{
    char c;
    int is_array = false;
    int len = strlen(string);

    /* XXX - This is a kludge, we should check the data type */
    if (len && (string[0] == '{') && (string[len-1] == '}'))
      is_array = true;

    for ( ; (c = *string) != '\0'; string++) {
      if (c == delim[0] || c == '\n' ||
          (c == '\\' && !is_array))
          fputc('\\', fp);
      else
          if (c == '\\' && is_array)
              if (*(string+1) == '\\') {
                  /* translate \\ to \\\\ */
                  fputc('\\', fp);
                  fputc('\\', fp);
                  fputc('\\', fp);
                  string++;
              } else if (*(string+1) == '"') {
                  /* translate \" to \\\" */
                  fputc('\\', fp);
                  fputc('\\', fp);
              }
      fputc(*string, fp);
    }
}

/*
 * Returns the number of tuples in a relation.  Unfortunately, currently
 * must do a scan of the entire relation to determine this.
 *
 * relation is expected to be an open relation descriptor.
 */
static int
CountTuples(Relation relation)
{
    HeapScanDesc scandesc;
    HeapTuple tuple;
    
    int i;
    
    scandesc = heap_beginscan(relation, 0, NULL, 0, NULL);
    
    for (tuple = heap_getnext(scandesc, 0, NULL), i = 0;
         tuple != NULL; 
         tuple = heap_getnext(scandesc, 0, NULL), i++)
	;
    heap_endscan(scandesc);
    return(i);
}
