copy.c

关系型数据库 Postgresql 6.5.2

/*-------------------------------------------------------------------------
 *
 * copy.c
 *
 * Copyright (c) 1994, Regents of the University of California
 *
 *
 * IDENTIFICATION
 *	  $Header: /usr/local/cvsroot/pgsql/src/backend/commands/copy.c,v 1.81 1999/07/03 00:32:39 momjian 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_shadow.h>
#include <commands/copy.h>
#include "commands/trigger.h"
#include <storage/fd.h>
#include <libpq/libpq.h>

#ifdef MULTIBYTE
#include "mb/pg_wchar.h"
#endif

#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, int is_array);
static int	CountTuples(Relation relation);

static int	lineno;

/*
 * Internal communications functions
 */
static void CopySendData(void *databuf, int datasize, FILE *fp);
static void CopySendString(char *str, FILE *fp);
static void CopySendChar(char c, FILE *fp);
static void CopyGetData(void *databuf, int datasize, FILE *fp);
static int	CopyGetChar(FILE *fp);
static int	CopyGetEof(FILE *fp);
static int	CopyPeekChar(FILE *fp);
static void CopyDonePeek(FILE *fp, int c, int pickup);

/*
 * CopySendData sends output data either to the file
 *	specified by fp or, if fp is NULL, using the standard
 *	backend->frontend functions
 *
 * CopySendString does the same for null-terminated strings
 * CopySendChar does the same for single characters
 *
 * NB: no data conversion is applied by these functions
 */
static void
CopySendData(void *databuf, int datasize, FILE *fp)
{
	if (!fp)
		pq_putbytes((char *) databuf, datasize);
	else
		fwrite(databuf, datasize, 1, fp);
}

static void
CopySendString(char *str, FILE *fp)
{
	CopySendData(str, strlen(str), fp);
}

static void
CopySendChar(char c, FILE *fp)
{
	CopySendData(&c, 1, fp);
}

/*
 * CopyGetData reads output data either from the file
 *	specified by fp or, if fp is NULL, using the standard
 *	backend->frontend functions
 *
 * CopyGetChar does the same for single characters
 * CopyGetEof checks if it's EOF on the input
 *
 * NB: no data conversion is applied by these functions
 */
static void
CopyGetData(void *databuf, int datasize, FILE *fp)
{
	if (!fp)
		pq_getbytes((char *) databuf, datasize);
	else
		fread(databuf, datasize, 1, fp);
}

static int
CopyGetChar(FILE *fp)
{
	if (!fp)
	{
		unsigned char ch;

		if (pq_getbytes((char *) &ch, 1))
			return EOF;
		return ch;
	}
	else
		return getc(fp);
}

static int
CopyGetEof(FILE *fp)
{
	if (!fp)
		return 0;				/* Never return EOF when talking to
								 * frontend ? */
	else
		return feof(fp);
}

/*
 * CopyPeekChar reads a byte in "peekable" mode.
 * after each call to CopyPeekChar, a call to CopyDonePeek _must_
 * follow.
 * CopyDonePeek will either take the peeked char off the steam
 * (if pickup is != 0) or leave it on the stream (if pickup == 0)
 */
static int
CopyPeekChar(FILE *fp)
{
	if (!fp)
		return pq_peekbyte();
	else
		return getc(fp);
}

static void
CopyDonePeek(FILE *fp, int c, int pickup)
{
	if (!fp)
	{
		if (pickup)
		{

			/*
			 * We want to pick it up - just receive again into dummy
			 * buffer
			 */
			char		c;

			pq_getbytes(&c, 1);
		}
		/* If we didn't want to pick it up, just leave it where it sits */
	}
	else
	{
		if (!pickup)
		{
			/* We don't want to pick it up - so put it back in there */
			ungetc(c, fp);
		}
		/* If we wanted to pick it up, it's already there */
	}
}



/*
 *	 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(ERROR, "COPY command failed.  Class %s "
			 "does not exist.", relname);

	result = pg_aclcheck(relname, UserName, required_access);
	if (result != ACLCHECK_OK)
		elog(ERROR, "%s: %s", relname, aclcheck_error_strings[result]);
	/* Above should not return */
	else if (!superuser() && !pipe)
		elog(ERROR, "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(ERROR, "You can't change sequence relation %s", relname);
			if (pipe)
			{
				if (IsUnderPostmaster)
				{
					ReceiveCopyBegin();
					fp = NULL;
				}
				else
					fp = stdin;
			}
			else
			{
#ifndef __CYGWIN32__
				fp = AllocateFile(filename, "r");
#else
				fp = AllocateFile(filename, "rb");
#endif
				if (fp == NULL)
					elog(ERROR, "COPY command, running in backend with "
						 "effective uid %d, could not open file '%s' for "
						 "reading.  Errno = %s (%d).",
						 geteuid(), filename, strerror(errno), errno);
			}
			CopyFrom(rel, binary, oids, fp, delim);
		}
		else
		{						/* copy from database to file */
			if (pipe)
			{
				if (IsUnderPostmaster)
				{
					SendCopyBegin();
					pq_startcopyout();
					fp = NULL;
				}
				else
					fp = stdout;
			}
			else
			{
				mode_t		oumask;		/* Pre-existing umask value */

				oumask = umask((mode_t) 0);
#ifndef __CYGWIN32__
				fp = AllocateFile(filename, "w");
#else
				fp = AllocateFile(filename, "wb");
#endif
				umask(oumask);
				if (fp == NULL)
					elog(ERROR, "COPY command, running in backend with "
						 "effective uid %d, could not open file '%s' for "
						 "writing.  Errno = %s (%d).",
						 geteuid(), filename, strerror(errno), errno);
			}
			CopyTo(rel, binary, oids, fp, delim);
		}
		if (!pipe)
		{
			FreeFile(fp);
		}
		else if (!from)
		{
			if (!binary)
				CopySendData("\\.\n", 3, fp);
			if (IsUnderPostmaster)
				pq_endcopyout(false);
		}
	}
}



static void
CopyTo(Relation rel, bool binary, bool oids, FILE *fp, char *delim)
{
	HeapTuple	tuple;
	HeapScanDesc scandesc;

	int32		attr_count,
				i;
	Form_pg_attribute *attr;
	FmgrInfo   *out_functions;
	Oid			out_func_oid;
	Oid		   *elements;
	int32	   *typmod;
	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, QuerySnapshot, 0, NULL);

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

	if (!binary)
	{
		out_functions = (FmgrInfo *) palloc(attr_count * sizeof(FmgrInfo));
		elements = (Oid *) palloc(attr_count * sizeof(Oid));
		typmod = (int32 *) palloc(attr_count * sizeof(int32));
		for (i = 0; i < attr_count; i++)
		{
			out_func_oid = (Oid) GetOutputFunction(attr[i]->atttypid);
			fmgr_info(out_func_oid, &out_functions[i]);
			elements[i] = GetTypeElement(attr[i]->atttypid);
			typmod[i] = attr[i]->atttypmod;
		}
		nulls = NULL;			/* meaningless, but compiler doesn't know
								 * that */
	}
	else
	{
		elements = NULL;
		typmod = NULL;
		out_functions = NULL;
		nulls = (char *) palloc(attr_count);
		for (i = 0; i < attr_count; i++)
			nulls[i] = ' ';

		/* XXX expensive */

		ntuples = CountTuples(rel);
		CopySendData(&ntuples, sizeof(int32), fp);
	}

	while (HeapTupleIsValid(tuple = heap_getnext(scandesc, 0)))
	{

		if (oids && !binary)
		{
			CopySendString(oidout(tuple->t_data->t_oid), fp);
			CopySendChar(delim[0], fp);
		}

		for (i = 0; i < attr_count; i++)
		{
			value = heap_getattr(tuple, i + 1, tupDesc, &isnull);
			if (!binary)
			{
				if (!isnull)
				{
					string = (char *) (*fmgr_faddr(&out_functions[i]))
						(value, elements[i], typmod[i]);
					CopyAttributeOut(fp, string, delim, attr[i]->attnelems);
					pfree(string);
				}
				else
					CopySendString("\\N", fp);	/* null indicator */

				if (i == attr_count - 1)
					CopySendChar('\n', fp);
				else
				{

					/*
					 * when copying out, only use the first char of the
					 * delim string
					 */
					CopySendChar(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)