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 */