gram.y

关系型数据库 Postgresql 6.5.2

raise_params	: raise_params raise_param
		    {
		        if ($1.nused == $1.nalloc) {
			    $1.nalloc *= 2;
			    $1.dtnums = repalloc($1.dtnums, sizeof(int) * $1.nalloc);
			}
			$1.dtnums[$1.nused++] = $2;

			$$.nalloc = $1.nalloc;
			$$.nused  = $1.nused;
			$$.dtnums = $1.dtnums;
		    }
		| raise_param
		    {
		        $$.nalloc = 1;
			$$.nused  = 1;
			$$.dtnums = palloc(sizeof(int) * $$.nalloc);
			$$.dtnums[0] = $1;
		    }
		;

raise_param	: ',' T_VARIABLE
		    {
		        $$ = yylval.var->varno;
		    }
		| ',' T_RECFIELD
		    {
		        $$ = yylval.recfield->rfno;
		    }
		| ',' T_TGARGV
		    {
		        $$ = yylval.trigarg->dno;
		    }
		;

loop_body	: proc_sect K_END K_LOOP ';'
		    { $$ = $1; }
		;

stmt_execsql	: execsql_start lno
		    {
		        PLpgSQL_stmt_execsql	*new;

			new = malloc(sizeof(PLpgSQL_stmt_execsql));
			new->cmd_type = PLPGSQL_STMT_EXECSQL;
			new->lineno   = $2;
			new->sqlstmt  = read_sqlstmt(';', ";", $1);

			$$ = (PLpgSQL_stmt *)new;
		    }
		;

execsql_start	: T_WORD
		    { $$ = strdup(yytext); }
		| T_ERROR
		    { $$ = strdup(yytext); }
		;

expr_until_semi	:
		    { $$ = plpgsql_read_expression(';', ";"); }
		;

expr_until_then	:
		    { $$ = plpgsql_read_expression(K_THEN, "THEN"); }
		;

expr_until_loop	:
		    { $$ = plpgsql_read_expression(K_LOOP, "LOOP"); }
		;

opt_label	:
		    {
			plpgsql_ns_push(NULL);
			$$ = NULL;
		    }
		| '<' '<' opt_lblname '>' '>'
		    {
			plpgsql_ns_push($3);
			$$ = $3;
		    }
		;

opt_exitlabel	:
		    { $$ = NULL; }
		| T_LABEL
		    { $$ = strdup(yytext); }
		;

opt_exitcond	: ';'
		    { $$ = NULL; }
		| K_WHEN expr_until_semi
		    { $$ = $2; }
		;

opt_lblname	: T_WORD
		    { $$ = strdup(yytext); }
		;

lno		:
		    {
			plpgsql_error_lineno = yylineno;
		        $$ = yylineno;
		    }
		;

%%

#ifndef YYBISON
#include "pl_scan.c" /* BSD yacc wants it here */
#endif


PLpgSQL_expr *
plpgsql_read_expression (int until, char *s)
{
    return read_sqlstmt(until, s, "SELECT ");
}


static PLpgSQL_expr *
read_sqlstmt (int until, char *s, char *sqlstart)
{
    int			tok;
    int			lno;
    PLpgSQL_dstring	ds;
    int			nparams = 0;
    int			params[1024];
    char		buf[32];
    PLpgSQL_expr	*expr;

    lno = yylineno;
    plpgsql_dstring_init(&ds);
    plpgsql_dstring_append(&ds, sqlstart);

    while((tok = yylex()) != until) {
	if (tok == ';') break;
	if (plpgsql_SpaceScanned) {
	    plpgsql_dstring_append(&ds, " ");
	}
        switch (tok) {
	    case T_VARIABLE:
		params[nparams] = yylval.var->varno;
		sprintf(buf, "$%d", ++nparams);
		plpgsql_dstring_append(&ds, buf);
		break;
	        
	    case T_RECFIELD:
		params[nparams] = yylval.recfield->rfno;
		sprintf(buf, "$%d", ++nparams);
		plpgsql_dstring_append(&ds, buf);
		break;
	        
	    case T_TGARGV:
		params[nparams] = yylval.trigarg->dno;
		sprintf(buf, "$%d", ++nparams);
		plpgsql_dstring_append(&ds, buf);
		break;
	        
	    default:
		if (tok == 0) {
		    plpgsql_error_lineno = lno;
		    plpgsql_comperrinfo();
		    elog(ERROR, "missing %s at end of SQL statement", s);
		}
		plpgsql_dstring_append(&ds, yytext);
		break;
        }
    }

    expr = malloc(sizeof(PLpgSQL_expr) + sizeof(int) * nparams - 1);
    expr->dtype		= PLPGSQL_DTYPE_EXPR;
    expr->query		= strdup(plpgsql_dstring_get(&ds));
    expr->plan		= NULL;
    expr->nparams	= nparams;
    while(nparams-- > 0) {
        expr->params[nparams] = params[nparams];
    }
    plpgsql_dstring_free(&ds);
    
    return expr;
}


static PLpgSQL_stmt *
make_select_stmt()
{
    int			tok;
    int			lno;
    PLpgSQL_dstring	ds;
    int			nparams = 0;
    int			params[1024];
    char		buf[32];
    PLpgSQL_expr	*expr;
    PLpgSQL_row		*row = NULL;
    PLpgSQL_rec		*rec = NULL;
    PLpgSQL_stmt_select	*select;
    int			have_nexttok = 0;

    lno = yylineno;
    plpgsql_dstring_init(&ds);
    plpgsql_dstring_append(&ds, "SELECT ");

    while((tok = yylex()) != K_INTO) {
	if (tok == ';') {
	    PLpgSQL_stmt_execsql	*execsql;

	    expr = malloc(sizeof(PLpgSQL_expr) + sizeof(int) * nparams - 1);
	    expr->dtype		= PLPGSQL_DTYPE_EXPR;
	    expr->query		= strdup(plpgsql_dstring_get(&ds));
	    expr->plan		= NULL;
	    expr->nparams	= nparams;
	    while(nparams-- > 0) {
		expr->params[nparams] = params[nparams];
	    }
	    plpgsql_dstring_free(&ds);

	    execsql = malloc(sizeof(PLpgSQL_stmt_execsql));
	    execsql->cmd_type = PLPGSQL_STMT_EXECSQL;
	    execsql->sqlstmt  = expr;

	    return (PLpgSQL_stmt *)execsql;
	}

	if (plpgsql_SpaceScanned) {
	    plpgsql_dstring_append(&ds, " ");
	}
        switch (tok) {
	    case T_VARIABLE:
		params[nparams] = yylval.var->varno;
		sprintf(buf, "$%d", ++nparams);
		plpgsql_dstring_append(&ds, buf);
		break;
	        
	    case T_RECFIELD:
		params[nparams] = yylval.recfield->rfno;
		sprintf(buf, "$%d", ++nparams);
		plpgsql_dstring_append(&ds, buf);
		break;
	        
	    case T_TGARGV:
		params[nparams] = yylval.trigarg->dno;
		sprintf(buf, "$%d", ++nparams);
		plpgsql_dstring_append(&ds, buf);
		break;
	        
	    default:
		if (tok == 0) {
		    plpgsql_error_lineno = yylineno;
		    plpgsql_comperrinfo();
		    elog(ERROR, "unexpected end of file");
		}
		plpgsql_dstring_append(&ds, yytext);
		break;
        }
    }

    tok = yylex();
    switch (tok) {
        case T_ROW:
	    row = yylval.row;
	    break;

        case T_RECORD:
	    rec = yylval.rec;
	    break;

	case T_VARIABLE:
	case T_RECFIELD:
	    {
		PLpgSQL_var	*var;
		PLpgSQL_recfield *recfield;
		int		nfields = 1;
		char		*fieldnames[1024];
		int		varnos[1024];

		switch (tok) {
		    case T_VARIABLE:
			var = yylval.var;
			fieldnames[0] = strdup(yytext);
			varnos[0]     = var->varno;
			break;
		    
		    case T_RECFIELD:
			recfield = yylval.recfield;
			fieldnames[0] = strdup(yytext);
			varnos[0]     = recfield->rfno;
			break;
		}

		while ((tok = yylex()) == ',') {
		    tok = yylex();
		    switch(tok) {
			case T_VARIABLE:
			    var = yylval.var;
			    fieldnames[nfields] = strdup(yytext);
			    varnos[nfields++]   = var->varno;
			    break;

			case T_RECFIELD:
			    recfield = yylval.recfield;
			    fieldnames[0] = strdup(yytext);
			    varnos[0]     = recfield->rfno;
			    break;

			default:
			    elog(ERROR, "plpgsql: %s is not a variable or record field", yytext);
		    }
		}
		row = malloc(sizeof(PLpgSQL_row));
		row->dtype = PLPGSQL_DTYPE_ROW;
		row->refname = strdup("*internal*");
		row->lineno = yylineno;
		row->rowtypeclass = InvalidOid;
		row->nfields = nfields;
		row->fieldnames = malloc(sizeof(char *) * nfields);
		row->varnos = malloc(sizeof(int) * nfields);
		while (--nfields >= 0) {
		    row->fieldnames[nfields] = fieldnames[nfields];
		    row->varnos[nfields] = varnos[nfields];
		}

		plpgsql_adddatum((PLpgSQL_datum *)row);

		have_nexttok = 1;
	    }
	    break;

        default:
	    {
		if (plpgsql_SpaceScanned) {
		    plpgsql_dstring_append(&ds, " ");
		}
		plpgsql_dstring_append(&ds, yytext);

		while(1) {
		    tok = yylex();
		    if (tok == ';') {
			PLpgSQL_stmt_execsql	*execsql;

			expr = malloc(sizeof(PLpgSQL_expr) + sizeof(int) * nparams - 1);
			expr->dtype		= PLPGSQL_DTYPE_EXPR;
			expr->query		= strdup(plpgsql_dstring_get(&ds));
			expr->plan		= NULL;
			expr->nparams	= nparams;
			while(nparams-- > 0) {
			    expr->params[nparams] = params[nparams];
			}
			plpgsql_dstring_free(&ds);

			execsql = malloc(sizeof(PLpgSQL_stmt_execsql));
			execsql->cmd_type = PLPGSQL_STMT_EXECSQL;
			execsql->sqlstmt  = expr;

			return (PLpgSQL_stmt *)execsql;
		    }

		    if (plpgsql_SpaceScanned) {
			plpgsql_dstring_append(&ds, " ");
		    }
		    switch (tok) {
			case T_VARIABLE:
			    params[nparams] = yylval.var->varno;
			    sprintf(buf, "$%d", ++nparams);
			    plpgsql_dstring_append(&ds, buf);
			    break;
			    
			case T_RECFIELD:
			    params[nparams] = yylval.recfield->rfno;
			    sprintf(buf, "$%d", ++nparams);
			    plpgsql_dstring_append(&ds, buf);
			    break;
			    
			case T_TGARGV:
			    params[nparams] = yylval.trigarg->dno;
			    sprintf(buf, "$%d", ++nparams);
			    plpgsql_dstring_append(&ds, buf);
			    break;
			    
			default:
			    if (tok == 0) {
				plpgsql_error_lineno = yylineno;
				plpgsql_comperrinfo();
				elog(ERROR, "unexpected end of file");
			    }
			    plpgsql_dstring_append(&ds, yytext);
			    break;
		    }
		}
	    }
    }

    /************************************************************
     * Eat up the rest of the statement after the target fields
     ************************************************************/
    while(1) {
	if (!have_nexttok) {
	    tok = yylex();
	}
	have_nexttok = 0;
	if (tok == ';') {
	    break;
	}

	if (plpgsql_SpaceScanned) {
	    plpgsql_dstring_append(&ds, " ");
	}
	switch (tok) {
	    case T_VARIABLE:
		params[nparams] = yylval.var->varno;
		sprintf(buf, "$%d", ++nparams);
		plpgsql_dstring_append(&ds, buf);
		break;
		
	    case T_RECFIELD:
		params[nparams] = yylval.recfield->rfno;
		sprintf(buf, "$%d", ++nparams);
		plpgsql_dstring_append(&ds, buf);
		break;
		
	    case T_TGARGV:
		params[nparams] = yylval.trigarg->dno;
		sprintf(buf, "$%d", ++nparams);
		plpgsql_dstring_append(&ds, buf);
		break;
		
	    default:
		if (tok == 0) {
		    plpgsql_error_lineno = yylineno;
		    plpgsql_comperrinfo();
		    elog(ERROR, "unexpected end of file");
		}
		plpgsql_dstring_append(&ds, yytext);
		break;
	}
    }

    expr = malloc(sizeof(PLpgSQL_expr) + sizeof(int) * (nparams - 1));
    expr->dtype		= PLPGSQL_DTYPE_EXPR;
    expr->query		= strdup(plpgsql_dstring_get(&ds));
    expr->plan		= NULL;
    expr->nparams	= nparams;
    while(nparams-- > 0) {
        expr->params[nparams] = params[nparams];
    }
    plpgsql_dstring_free(&ds);

    select = malloc(sizeof(PLpgSQL_stmt_select));
    memset(select, 0, sizeof(PLpgSQL_stmt_select));
    select->cmd_type = PLPGSQL_STMT_SELECT;
    select->rec      = rec;
    select->row      = row;
    select->query    = expr;
    
    return (PLpgSQL_stmt *)select;
}


static PLpgSQL_expr *
make_tupret_expr(PLpgSQL_row *row)
{
    PLpgSQL_dstring	ds;
    PLpgSQL_expr	*expr;
    int			i;
    char		buf[16];

    expr = malloc(sizeof(PLpgSQL_expr) + sizeof(int) * (row->nfields - 1));
    expr->dtype		= PLPGSQL_DTYPE_EXPR;

    plpgsql_dstring_init(&ds);
    plpgsql_dstring_append(&ds, "SELECT ");

    for (i = 0; i < row->nfields; i++) {
        sprintf(buf, "%s$%d", (i > 0) ? "," : "", i + 1);
	plpgsql_dstring_append(&ds, buf);
	expr->params[i] = row->varnos[i];
    }

    expr->query         = strdup(plpgsql_dstring_get(&ds));
    expr->plan          = NULL;
    expr->plan_argtypes = NULL;
    expr->nparams       = row->nfields;

    plpgsql_dstring_free(&ds);
    return expr;
}