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347 lines
12 KiB
C
347 lines
12 KiB
C
/*-------------------------------------------------------------------------
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*
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* libpq-int.h
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* This file contains internal definitions meant to be used only by
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* the frontend libpq library, not by applications that call it.
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*
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* An application can include this file if it wants to bypass the
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* official API defined by libpq-fe.h, but code that does so is much
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* more likely to break across PostgreSQL releases than code that uses
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* only the official API.
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*
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* Portions Copyright (c) 1996-2001, PostgreSQL Global Development Group
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* Portions Copyright (c) 1994, Regents of the University of California
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*
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* $Id: libpq-int.h,v 1.35 2001/07/06 19:04:23 petere Exp $
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*
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*-------------------------------------------------------------------------
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*/
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#ifndef LIBPQ_INT_H
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#define LIBPQ_INT_H
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/* We assume libpq-fe.h has already been included. */
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#include "postgres_fe.h"
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/* include stuff common to fe and be */
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#include "libpq/pqcomm.h"
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#include "lib/dllist.h"
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/* include stuff found in fe only */
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#include "pqexpbuffer.h"
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#ifdef USE_SSL
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#include <openssl/ssl.h>
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#include <openssl/err.h>
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#endif
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/* libpq supports this version of the frontend/backend protocol.
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*
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* NB: we used to use PG_PROTOCOL_LATEST from the backend pqcomm.h file,
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* but that's not really the right thing: just recompiling libpq
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* against a more recent backend isn't going to magically update it
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* for most sorts of protocol changes. So, when you change libpq
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* to support a different protocol revision, you have to change this
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* constant too. PG_PROTOCOL_EARLIEST and PG_PROTOCOL_LATEST in
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* pqcomm.h describe what the backend knows, not what libpq knows.
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*/
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#define PG_PROTOCOL_LIBPQ PG_PROTOCOL(2,0)
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/*
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* POSTGRES backend dependent Constants.
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*/
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#define PQERRORMSG_LENGTH 1024
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#define CMDSTATUS_LEN 40
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/*
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* PGresult and the subsidiary types PGresAttDesc, PGresAttValue
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* represent the result of a query (or more precisely, of a single SQL
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* command --- a query string given to PQexec can contain multiple commands).
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* Note we assume that a single command can return at most one tuple group,
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* hence there is no need for multiple descriptor sets.
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*/
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/* Subsidiary-storage management structure for PGresult.
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* See space management routines in fe-exec.c for details.
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* Note that space[k] refers to the k'th byte starting from the physical
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* head of the block --- it's a union, not a struct!
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*/
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typedef union pgresult_data PGresult_data;
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union pgresult_data
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{
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PGresult_data *next; /* link to next block, or NULL */
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char space[1]; /* dummy for accessing block as bytes */
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};
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/* Data about a single attribute (column) of a query result */
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typedef struct pgresAttDesc
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{
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char *name; /* type name */
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Oid typid; /* type id */
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int typlen; /* type size */
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int atttypmod; /* type-specific modifier info */
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} PGresAttDesc;
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/* Data for a single attribute of a single tuple */
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/* We use char* for Attribute values.
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The value pointer always points to a null-terminated area; we add a
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null (zero) byte after whatever the backend sends us. This is only
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particularly useful for ASCII tuples ... with a binary value, the
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value might have embedded nulls, so the application can't use C string
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operators on it. But we add a null anyway for consistency.
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Note that the value itself does not contain a length word.
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A NULL attribute is a special case in two ways: its len field is NULL_LEN
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and its value field points to null_field in the owning PGresult. All the
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NULL attributes in a query result point to the same place (there's no need
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to store a null string separately for each one).
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*/
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#define NULL_LEN (-1) /* pg_result len for NULL value */
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typedef struct pgresAttValue
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{
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int len; /* length in bytes of the value */
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char *value; /* actual value, plus terminating zero
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* byte */
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} PGresAttValue;
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struct pg_result
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{
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int ntups;
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int numAttributes;
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PGresAttDesc *attDescs;
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PGresAttValue **tuples; /* each PGresTuple is an array of
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* PGresAttValue's */
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int tupArrSize; /* size of tuples array allocated */
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ExecStatusType resultStatus;
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char cmdStatus[CMDSTATUS_LEN]; /* cmd status from the
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* last query */
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int binary; /* binary tuple values if binary == 1,
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* otherwise ASCII */
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/*
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* The conn link in PGresult is no longer used by any libpq code. It
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* should be removed entirely, because it could be a dangling link
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* (the application could keep the PGresult around longer than it
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* keeps the PGconn!) But there may be apps out there that depend on
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* it, so we will leave it here at least for a release or so.
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*/
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PGconn *xconn; /* connection we did the query on, if any */
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/*
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* These fields are copied from the originating PGconn, so that
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* operations on the PGresult don't have to reference the PGconn.
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*/
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PQnoticeProcessor noticeHook; /* notice/error message processor */
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void *noticeArg;
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int client_encoding;/* encoding id */
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char *errMsg; /* error message, or NULL if no error */
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/* All NULL attributes in the query result point to this null string */
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char null_field[1];
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/*
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* Space management information. Note that attDescs and errMsg, if
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* not null, point into allocated blocks. But tuples points to a
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* separately malloc'd block, so that we can realloc it.
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*/
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PGresult_data *curBlock; /* most recently allocated block */
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int curOffset; /* start offset of free space in block */
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int spaceLeft; /* number of free bytes remaining in block */
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};
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/* PGAsyncStatusType defines the state of the query-execution state machine */
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typedef enum
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{
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PGASYNC_IDLE, /* nothing's happening, dude */
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PGASYNC_BUSY, /* query in progress */
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PGASYNC_READY, /* result ready for PQgetResult */
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PGASYNC_COPY_IN, /* Copy In data transfer in progress */
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PGASYNC_COPY_OUT /* Copy Out data transfer in progress */
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} PGAsyncStatusType;
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/* PGSetenvStatusType defines the state of the PQSetenv state machine */
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typedef enum
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{
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SETENV_STATE_OPTION_SEND, /* About to send an Environment Option */
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SETENV_STATE_OPTION_WAIT, /* Waiting for above send to complete */
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/* these next two are only used in MULTIBYTE mode */
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SETENV_STATE_ENCODINGS_SEND,/* About to send an "encodings" query */
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SETENV_STATE_ENCODINGS_WAIT,/* Waiting for query to complete */
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SETENV_STATE_IDLE
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} PGSetenvStatusType;
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/* large-object-access data ... allocated only if large-object code is used. */
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typedef struct pgLobjfuncs
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{
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Oid fn_lo_open; /* OID of backend function lo_open */
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Oid fn_lo_close; /* OID of backend function lo_close */
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Oid fn_lo_creat; /* OID of backend function lo_creat */
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Oid fn_lo_unlink; /* OID of backend function lo_unlink */
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Oid fn_lo_lseek; /* OID of backend function lo_lseek */
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Oid fn_lo_tell; /* OID of backend function lo_tell */
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Oid fn_lo_read; /* OID of backend function LOread */
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Oid fn_lo_write; /* OID of backend function LOwrite */
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} PGlobjfuncs;
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/* PGconn stores all the state data associated with a single connection
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* to a backend.
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*/
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struct pg_conn
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{
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/* Saved values of connection options */
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char *pghost; /* the machine on which the server is
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* running */
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char *pghostaddr; /* the IPv4 address of the machine on
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* which the server is running, in IPv4
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* numbers-and-dots notation. Takes
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* precedence over above. */
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char *pgport; /* the server's communication port */
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char *pgunixsocket; /* the Unix-domain socket that the server
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* is listening on; if NULL, uses a
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* default constructed from pgport */
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char *pgtty; /* tty on which the backend messages is
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* displayed (NOT ACTUALLY USED???) */
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char *pgoptions; /* options to start the backend with */
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char *dbName; /* database name */
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char *pguser; /* Postgres username and password, if any */
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char *pgpass;
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/* Optional file to write trace info to */
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FILE *Pfdebug;
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/* Callback procedure for notice/error message processing */
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PQnoticeProcessor noticeHook;
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void *noticeArg;
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/* Status indicators */
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ConnStatusType status;
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PGAsyncStatusType asyncStatus;
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Dllist *notifyList; /* Notify msgs not yet handed to
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* application */
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/* Connection data */
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int sock; /* Unix FD for socket, -1 if not connected */
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SockAddr laddr; /* Local address */
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SockAddr raddr; /* Remote address */
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int raddr_len; /* Length of remote address */
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/* Miscellaneous stuff */
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int be_pid; /* PID of backend --- needed for cancels */
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int be_key; /* key of backend --- needed for cancels */
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char salt[2]; /* password salt received from backend */
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PGlobjfuncs *lobjfuncs; /* private state for large-object access
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* fns */
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/* Buffer for data received from backend and not yet processed */
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char *inBuffer; /* currently allocated buffer */
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int inBufSize; /* allocated size of buffer */
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int inStart; /* offset to first unconsumed data in
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* buffer */
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int inCursor; /* next byte to tentatively consume */
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int inEnd; /* offset to first position after avail
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* data */
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int nonblocking; /* whether this connection is using a
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* blocking socket to the backend or not */
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/* Buffer for data not yet sent to backend */
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char *outBuffer; /* currently allocated buffer */
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int outBufSize; /* allocated size of buffer */
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int outCount; /* number of chars waiting in buffer */
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/* Status for asynchronous result construction */
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PGresult *result; /* result being constructed */
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PGresAttValue *curTuple; /* tuple currently being read */
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/* Status for sending environment info. Used during PQSetenv only. */
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PGSetenvStatusType setenv_state;
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const struct EnvironmentOptions *next_eo;
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#ifdef USE_SSL
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bool allow_ssl_try; /* Allowed to try SSL negotiation */
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bool require_ssl; /* Require SSL to make connection */
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SSL *ssl; /* SSL status, if have SSL connection */
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#endif
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/* Buffer for current error message */
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PQExpBufferData errorMessage; /* expansible string */
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/* Buffer for receiving various parts of messages */
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PQExpBufferData workBuffer; /* expansible string */
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int client_encoding;/* encoding id */
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};
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/* String descriptions of the ExecStatusTypes.
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* direct use of this array is deprecated; call PQresStatus() instead.
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*/
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extern char *const pgresStatus[];
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/* ----------------
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* Internal functions of libpq
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* Functions declared here need to be visible across files of libpq,
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* but are not intended to be called by applications. We use the
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* convention "pqXXX" for internal functions, vs. the "PQxxx" names
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* used for application-visible routines.
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* ----------------
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*/
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/* === in fe-connect.c === */
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extern int pqPacketSend(PGconn *conn, const char *buf, size_t len);
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/* === in fe-exec.c === */
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extern void pqSetResultError(PGresult *res, const char *msg);
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extern void *pqResultAlloc(PGresult *res, size_t nBytes, bool isBinary);
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extern char *pqResultStrdup(PGresult *res, const char *str);
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extern void pqClearAsyncResult(PGconn *conn);
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/* === in fe-misc.c === */
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/*
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* "Get" and "Put" routines return 0 if successful, EOF if not. Note that
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* for Get, EOF merely means the buffer is exhausted, not that there is
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* necessarily any error.
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*/
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extern int pqGetc(char *result, PGconn *conn);
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extern int pqPutc(char c, PGconn *conn);
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extern int pqGets(PQExpBuffer buf, PGconn *conn);
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extern int pqPuts(const char *s, PGconn *conn);
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extern int pqGetnchar(char *s, size_t len, PGconn *conn);
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extern int pqPutnchar(const char *s, size_t len, PGconn *conn);
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extern int pqGetInt(int *result, size_t bytes, PGconn *conn);
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extern int pqPutInt(int value, size_t bytes, PGconn *conn);
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extern int pqReadData(PGconn *conn);
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extern int pqFlush(PGconn *conn);
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extern int pqWait(int forRead, int forWrite, PGconn *conn);
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extern int pqReadReady(PGconn *conn);
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extern int pqWriteReady(PGconn *conn);
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/* bits in a byte */
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#define BYTELEN 8
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/* fall back options if they are not specified by arguments or defined
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by environment variables */
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#define DefaultHost "localhost"
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#define DefaultTty ""
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#define DefaultOption ""
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#define DefaultAuthtype ""
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#define DefaultPassword ""
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/*
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* this is so that we can check is a connection is non-blocking internally
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* without the overhead of a function call
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*/
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#define pqIsnonblocking(conn) ((conn)->nonblocking)
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#endif /* LIBPQ_INT_H */
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