libpq-fe.h


/*-------------------------------------------------------------------------
 *
 * libpq-fe.h
 *	  This file contains definitions for structures and
 *	  externs for functions used by frontend postgres applications.
 *
 * Portions Copyright (c) 1996-2003, PostgreSQL Global Development Group
 * Portions Copyright (c) 1994, Regents of the University of California
 *
 * $Id: libpq-fe.h,v 1.100 2003/08/27 00:33:34 petere Exp $
 *
 *-------------------------------------------------------------------------
 */

#ifndef LIBPQ_FE_H
#define LIBPQ_FE_H

#ifdef __cplusplus
extern "C" {
#endif

#include <stdio.h>

/*
 * postgres_ext.h defines the backend's externally visible types,
 * such as Oid.
 */
#include "postgres_ext.h"

/* SSL type is needed here only to declare PQgetssl() */
#ifdef USE_SSL
#include <openssl/ssl.h>
#endif

/* Application-visible enum types */

  typedef enum {
    /*
     * Although it is okay to add to this list, values which become unused
     * should never be removed, nor should constants be redefined - that
     * would break compatibility with existing code.
     */
    CONNECTION_OK,
    CONNECTION_BAD,
    /* Non-blocking mode only below here */

    /*
     * The existence of these should never be relied upon - they should
     * only be used for user feedback or similar purposes.
     */
    CONNECTION_STARTED,         /* Waiting for connection to be made.  */
    CONNECTION_MADE,            /* Connection OK; waiting to send.         */
    CONNECTION_AWAITING_RESPONSE,       /* Waiting for a response from the
                                         * postmaster.            */
    CONNECTION_AUTH_OK,         /* Received authentication; waiting for
                                 * backend startup. */
    CONNECTION_SETENV,          /* Negotiating environment. */
    CONNECTION_SSL_STARTUP,     /* Negotiating SSL. */
    CONNECTION_NEEDED           /* Internal state: connect() needed */
  } ConnStatusType;

  typedef enum {
    PGRES_POLLING_FAILED = 0,
    PGRES_POLLING_READING,      /* These two indicate that one may        */
    PGRES_POLLING_WRITING,      /* use select before polling again.   */
    PGRES_POLLING_OK,
    PGRES_POLLING_ACTIVE        /* unused; keep for awhile for backwards
                                 * compatibility */
  } PostgresPollingStatusType;

  typedef enum {
    PGRES_EMPTY_QUERY = 0,      /* empty query string was executed */
    PGRES_COMMAND_OK,           /* a query command that doesn't return
                                 * anything was executed properly by the
                                 * backend */
    PGRES_TUPLES_OK,            /* a query command that returns tuples was
                                 * executed properly by the backend,
                                 * PGresult contains the result tuples */
    PGRES_COPY_OUT,             /* Copy Out data transfer in progress */
    PGRES_COPY_IN,              /* Copy In data transfer in progress */
    PGRES_BAD_RESPONSE,         /* an unexpected response was recv'd from
                                 * the backend */
    PGRES_NONFATAL_ERROR,       /* notice or warning message */
    PGRES_FATAL_ERROR           /* query failed */
  } ExecStatusType;

  typedef enum {
    PQTRANS_IDLE,               /* connection idle */
    PQTRANS_ACTIVE,             /* command in progress */
    PQTRANS_INTRANS,            /* idle, within transaction block */
    PQTRANS_INERROR,            /* idle, within failed transaction */
    PQTRANS_UNKNOWN             /* cannot determine status */
  } PGTransactionStatusType;

  typedef enum {
    PQERRORS_TERSE,             /* single-line error messages */
    PQERRORS_DEFAULT,           /* recommended style */
    PQERRORS_VERBOSE            /* all the facts, ma'am */
  } PGVerbosity;

/* PGconn encapsulates a connection to the backend.
 * The contents of this struct are not supposed to be known to applications.
 */
  typedef struct pg_conn PGconn;

/* PGresult encapsulates the result of a query (or more precisely, of a single
 * SQL command --- a query string given to PQsendQuery can contain multiple
 * commands and thus return multiple PGresult objects).
 * The contents of this struct are not supposed to be known to applications.
 */
  typedef struct pg_result PGresult;

/* PGnotify represents the occurrence of a NOTIFY message.
 * Ideally this would be an opaque typedef, but it's so simple that it's
 * unlikely to change.
 * NOTE: in Postgres 6.4 and later, the be_pid is the notifying backend's,
 * whereas in earlier versions it was always your own backend's PID.
 */
  typedef struct pgNotify {
    char *relname;              /* notification condition name */
    int32_t be_pid;                 /* process ID of server process */
    char *extra;                /* notification parameter */
  } PGnotify;

/* Function types for notice-handling callbacks */
  typedef void (*PQnoticeReceiver) (void *arg, const PGresult * res);
  typedef void (*PQnoticeProcessor) (void *arg, const char *message);

/* Print options for PQprint() */
  typedef char pqbool;

  typedef struct _PQprintOpt {
    pqbool header;              /* print output field headings and row
                                 * count */
    pqbool align;               /* fill align the fields */
    pqbool standard;            /* old brain dead format */
    pqbool html3;               /* output html tables */
    pqbool expanded;            /* expand tables */
    pqbool pager;               /* use pager for output if needed */
    char *fieldSep;             /* field separator */
    char *tableOpt;             /* insert to HTML <table ...> */
    char *caption;              /* HTML <caption> */
    char **fieldName;           /* null terminated array of repalcement
                                 * field names */
  } PQprintOpt;

/* ----------------
 * Structure for the conninfo parameter definitions returned by PQconndefaults
 *
 * All fields except "val" point at static strings which must not be altered.
 * "val" is either NULL or a malloc'd current-value string.  PQconninfoFree()
 * will release both the val strings and the PQconninfoOption array itself.
 * ----------------
 */
  typedef struct _PQconninfoOption {
    char *keyword;              /* The keyword of the option                    */
    char *envvar;               /* Fallback environment variable name   */
    char *compiled;             /* Fallback compiled in default value   */
    char *val;                  /* Option's current value, or NULL               */
    char *label;                /* Label for field in connect dialog    */
    char *dispchar;             /* Character to display for this field in
                                 * a connect dialog. Values are: ""
                                 * Display entered value as is "*"
                                 * Password field - hide value "D"      Debug
                                 * option - don't show by default */
    int32_t dispsize;               /* Field size in characters for dialog  */
  } PQconninfoOption;

/* ----------------
 * PQArgBlock -- structure for PQfn() arguments
 * ----------------
 */
  typedef struct {
    int32_t len;
    int32_t isint;
    union {
      int32_t *ptr;                 /* can't use void (dec compiler barfs)   */
      int32_t integer;
    } u;
  } PQArgBlock;

/* ----------------
 * Exported functions of libpq
 * ----------------
 */

/* ===	in fe-connect.c === */

/* make a new client connection to the backend */

/* Asynchronous (non-blocking) */
  extern PGconn *PQconnectStart(const char *conninfo);
  extern PostgresPollingStatusType PQconnectPoll(PGconn * conn);

/* Synchronous (blocking) */
  extern PGconn *PQconnectdb(const char *conninfo);
  extern PGconn *PQsetdbLogin(const char *pghost, const char *pgport, const char *pgoptions, const char *pgtty, const char *dbName, const char *login, const char *pwd);

#define PQsetdb(M_PGHOST,M_PGPORT,M_PGOPT,M_PGTTY,M_DBNAME)  \
	PQsetdbLogin(M_PGHOST, M_PGPORT, M_PGOPT, M_PGTTY, M_DBNAME, NULL, NULL)

/* close the current connection and free the PGconn data structure */
  extern void PQfinish(PGconn * conn);

/* get info about connection options known to PQconnectdb */
  extern PQconninfoOption *PQconndefaults(void);

/* free the data structure returned by PQconndefaults() */
  extern void PQconninfoFree(PQconninfoOption * connOptions);

/*
 * close the current connection and restablish a new one with the same
 * parameters
 */

/* Asynchronous (non-blocking) */
  extern int32_t PQresetStart(PGconn * conn);
  extern PostgresPollingStatusType PQresetPoll(PGconn * conn);

/* Synchronous (blocking) */
  extern void PQreset(PGconn * conn);

/* issue a cancel request */
  extern int32_t PQrequestCancel(PGconn * conn);

/* Accessor functions for PGconn objects */
  extern char *PQdb(const PGconn * conn);
  extern char *PQuser(const PGconn * conn);
  extern char *PQpass(const PGconn * conn);
  extern char *PQhost(const PGconn * conn);
  extern char *PQport(const PGconn * conn);
  extern char *PQtty(const PGconn * conn);
  extern char *PQoptions(const PGconn * conn);
  extern ConnStatusType PQstatus(const PGconn * conn);
  extern PGTransactionStatusType PQtransactionStatus(const PGconn * conn);
  extern const char *PQparameterStatus(const PGconn * conn, const char *paramName);
  extern int32_t PQprotocolVersion(const PGconn * conn);
  extern char *PQerrorMessage(const PGconn * conn);
  extern int32_t PQsocket(const PGconn * conn);
  extern int32_t PQbackendPID(const PGconn * conn);
  extern int32_t PQclientEncoding(const PGconn * conn);
  extern int32_t PQsetClientEncoding(PGconn * conn, const char *encoding);

#ifdef USE_SSL

/* Get the SSL structure associated with a connection */
  extern SSL *PQgetssl(PGconn * conn);
#endif

/* Set verbosity for PQerrorMessage and PQresultErrorMessage */
  extern PGVerbosity PQsetErrorVerbosity(PGconn * conn, PGVerbosity verbosity);

/* Enable/disable tracing */
  extern void PQtrace(PGconn * conn, FILE * debug_port);
  extern void PQuntrace(PGconn * conn);

/* Override default notice handling routines */
  extern PQnoticeReceiver PQsetNoticeReceiver(PGconn * conn, PQnoticeReceiver proc, void *arg);
  extern PQnoticeProcessor PQsetNoticeProcessor(PGconn * conn, PQnoticeProcessor proc, void *arg);

/* === in fe-exec.c === */

/* Simple synchronous query */
  extern PGresult *PQexec(PGconn * conn, const char *query);
  extern PGresult *PQexecParams(PGconn * conn,
                                const char *command,
                                int32_t nParams, const Oid * paramTypes, const char *const *paramValues, const int32_t *paramLengths, const int32_t *paramFormats, int32_t resultFormat);
  extern PGresult *PQexecPrepared(PGconn * conn,
                                  const char *stmtName, int32_t nParams, const char *const *paramValues, const int32_t *paramLengths, const int32_t *paramFormats, int32_t resultFormat);

/* Interface for multiple-result or asynchronous queries */
  extern int32_t PQsendQuery(PGconn * conn, const char *query);
  extern int32_t PQsendQueryParams(PGconn * conn,
                               const char *command,
                               int32_t nParams, const Oid * paramTypes, const char *const *paramValues, const int32_t *paramLengths, const int32_t *paramFormats, int32_t resultFormat);
  extern int32_t PQsendQueryPrepared(PGconn * conn,
                                 const char *stmtName, int32_t nParams, const char *const *paramValues, const int32_t *paramLengths, const int32_t *paramFormats, int32_t resultFormat);
  extern PGresult *PQgetResult(PGconn * conn);

/* Routines for managing an asynchronous query */
  extern int32_t PQisBusy(PGconn * conn);
  extern int32_t PQconsumeInput(PGconn * conn);

/* LISTEN/NOTIFY support */
  extern PGnotify *PQnotifies(PGconn * conn);

/* Routines for copy in/out */
  extern int32_t PQputCopyData(PGconn * conn, const char *buffer, int32_t nbytes);
  extern int32_t PQputCopyEnd(PGconn * conn, const char *errormsg);
  extern int32_t PQgetCopyData(PGconn * conn, char **buffer, int32_t async);

/* Deprecated routines for copy in/out */
  extern int32_t PQgetline(PGconn * conn, char *string, int32_t length);
  extern int32_t PQputline(PGconn * conn, const char *string);
  extern int32_t PQgetlineAsync(PGconn * conn, char *buffer, int32_t bufsize);
  extern int32_t PQputnbytes(PGconn * conn, const char *buffer, int32_t nbytes);
  extern int32_t PQendcopy(PGconn * conn);

/* Set blocking/nonblocking connection to the backend */
  extern int32_t PQsetnonblocking(PGconn * conn, int32_t arg);
  extern int32_t PQisnonblocking(const PGconn * conn);

/* Force the write buffer to be written (or at least try) */
  extern int32_t PQflush(PGconn * conn);

/*
 * "Fast path" interface --- not really recommended for application
 * use
 */
  extern PGresult *PQfn(PGconn * conn, int32_t fnid, int32_t *result_buf, int32_t *result_len, int32_t result_is_int, const PQArgBlock * args, int32_t nargs);

/* Accessor functions for PGresult objects */
  extern ExecStatusType PQresultStatus(const PGresult * res);
  extern char *PQresStatus(ExecStatusType status);
  extern char *PQresultErrorMessage(const PGresult * res);
  extern char *PQresultErrorField(const PGresult * res, int32_t fieldcode);
  extern int32_t PQntuples(const PGresult * res);
  extern int32_t PQnfields(const PGresult * res);
  extern int32_t PQbinaryTuples(const PGresult * res);
  extern char *PQfname(const PGresult * res, int32_t field_num);
  extern int32_t PQfnumber(const PGresult * res, const char *field_name);
  extern Oid PQftable(const PGresult * res, int32_t field_num);
  extern int32_t PQftablecol(const PGresult * res, int32_t field_num);
  extern int32_t PQfformat(const PGresult * res, int32_t field_num);
  extern Oid PQftype(const PGresult * res, int32_t field_num);
  extern int32_t PQfsize(const PGresult * res, int32_t field_num);
  extern int32_t PQfmod(const PGresult * res, int32_t field_num);
  extern char *PQcmdStatus(PGresult * res);
  extern char *PQoidStatus(const PGresult * res);       /* old and ugly */
  extern Oid PQoidValue(const PGresult * res);  /* new and improved */
  extern char *PQcmdTuples(PGresult * res);
  extern char *PQgetvalue(const PGresult * res, int32_t tup_num, int32_t field_num);
  extern int32_t PQgetlength(const PGresult * res, int32_t tup_num, int32_t field_num);
  extern int32_t PQgetisnull(const PGresult * res, int32_t tup_num, int32_t field_num);

/* Delete a PGresult */
  extern void PQclear(PGresult * res);

/* For freeing other alloc'd results, such as PGnotify structs */
  extern void PQfreemem(void *ptr);

/* Exists for backward compatibility.  bjm 2003-03-24 */
#define PQfreeNotify(ptr) PQfreemem(ptr)

/*
 * Make an empty PGresult with given status (some apps find this
 * useful). If conn is not NULL and status indicates an error, the
 * conn's errorMessage is copied.
 */
  extern PGresult *PQmakeEmptyPGresult(PGconn * conn, ExecStatusType status);


/* Quoting strings before inclusion in queries. */
  extern size_t PQescapeString(char *to, const char *from, size_t length);
  extern unsigned char *PQescapeBytea(const unsigned char *bintext, size_t binlen, size_t * bytealen);
  extern unsigned char *PQunescapeBytea(const unsigned char *strtext, size_t * retbuflen);


/* === in fe-print.c === */

  extern void
    PQprint(FILE * fout,        /* output stream */
            const PGresult * res, const PQprintOpt * ps);       /* option structure */

/*
 * really old printing routines
 */
  extern void
    PQdisplayTuples(const PGresult * res, FILE * fp,    /* where to send the output */
                    int32_t fillAlign,      /* pad the fields with spaces */
                    const char *fieldSep,       /* field separator */
                    int32_t printHeader,    /* display headers? */
                    int32_t quiet);

  extern void
    PQprintTuples(const PGresult * res, FILE * fout,    /* output stream */
                  int32_t printAttName,     /* print attribute names */
                  int32_t terseOutput,      /* delimiter bars */
                  int32_t width);   /* width of column, if 0, use variable
                                 * width */


/* === in fe-lobj.c === */

/* Large-object access routines */
  extern int32_t lo_open(PGconn * conn, Oid lobjId, int32_t mode);
  extern int32_t lo_close(PGconn * conn, int32_t fd);
  extern int32_t lo_read(PGconn * conn, int32_t fd, char *buf, size_t len);
  extern int32_t lo_write(PGconn * conn, int32_t fd, char *buf, size_t len);
  extern int32_t lo_lseek(PGconn * conn, int32_t fd, int32_t offset, int32_t whence);
  extern Oid lo_creat(PGconn * conn, int32_t mode);
  extern int32_t lo_tell(PGconn * conn, int32_t fd);
  extern int32_t lo_unlink(PGconn * conn, Oid lobjId);
  extern Oid lo_import(PGconn * conn, const char *filename);
  extern int32_t lo_export(PGconn * conn, Oid lobjId, const char *filename);

/* === in fe-misc.c === */

/* Determine length of multibyte encoded char at *s */
  extern int32_t PQmblen(const unsigned char *s, int32_t encoding);

/* Get encoding id from environment variable PGCLIENTENCODING */
  extern int32_t PQenv2encoding(void);

#ifdef __cplusplus
}
#endif
#endif                          /* LIBPQ_FE_H */