pg_backup_custom.c

PostgreSQL 8.1.4的源码 适用于Linux下的开源数据库系统

/*-------------------------------------------------------------------------
 *
 * pg_backup_custom.c
 *
 *	Implements the custom output format.
 *
 *	The comments with the routined in this code are a good place to
 *	understand how to write a new format.
 *
 *	See the headers to pg_restore for more details.
 *
 * Copyright (c) 2000, Philip Warner
 *		Rights are granted to use this software in any way so long
 *		as this notice is not removed.
 *
 *	The author is not responsible for loss or damages that may
 *	and any liability will be limited to the time taken to fix any
 *	related bug.
 *
 *
 * IDENTIFICATION
 *		$PostgreSQL: pgsql/src/bin/pg_dump/pg_backup_custom.c,v 1.33 2005/10/15 02:49:38 momjian Exp $
 *
 *-------------------------------------------------------------------------
 */

#include "pg_backup.h"
#include "pg_backup_archiver.h"

/*--------
 * Routines in the format interface
 *--------
 */

static void _ArchiveEntry(ArchiveHandle *AH, TocEntry *te);
static void _StartData(ArchiveHandle *AH, TocEntry *te);
static size_t _WriteData(ArchiveHandle *AH, const void *data, size_t dLen);
static void _EndData(ArchiveHandle *AH, TocEntry *te);
static int	_WriteByte(ArchiveHandle *AH, const int i);
static int	_ReadByte(ArchiveHandle *);
static size_t _WriteBuf(ArchiveHandle *AH, const void *buf, size_t len);
static size_t _ReadBuf(ArchiveHandle *AH, void *buf, size_t len);
static void _CloseArchive(ArchiveHandle *AH);
static void _PrintTocData(ArchiveHandle *AH, TocEntry *te, RestoreOptions *ropt);
static void _WriteExtraToc(ArchiveHandle *AH, TocEntry *te);
static void _ReadExtraToc(ArchiveHandle *AH, TocEntry *te);
static void _PrintExtraToc(ArchiveHandle *AH, TocEntry *te);

static void _PrintData(ArchiveHandle *AH);
static void _skipData(ArchiveHandle *AH);
static void _skipBlobs(ArchiveHandle *AH);

static void _StartBlobs(ArchiveHandle *AH, TocEntry *te);
static void _StartBlob(ArchiveHandle *AH, TocEntry *te, Oid oid);
static void _EndBlob(ArchiveHandle *AH, TocEntry *te, Oid oid);
static void _EndBlobs(ArchiveHandle *AH, TocEntry *te);
static void _LoadBlobs(ArchiveHandle *AH);

/*------------
 * Buffers used in zlib compression and extra data stored in archive and
 * in TOC entries.
 *------------
 */
#define zlibOutSize 4096
#define zlibInSize	4096

typedef struct
{
	z_streamp	zp;
	char	   *zlibOut;
	char	   *zlibIn;
	size_t		inSize;
	int			hasSeek;
	off_t		filePos;
	off_t		dataStart;
} lclContext;

typedef struct
{
	int			dataState;
	off_t		dataPos;
} lclTocEntry;


/*------
 * Static declarations
 *------
 */
static void _readBlockHeader(ArchiveHandle *AH, int *type, int *id);
static void _StartDataCompressor(ArchiveHandle *AH, TocEntry *te);
static void _EndDataCompressor(ArchiveHandle *AH, TocEntry *te);
static off_t _getFilePos(ArchiveHandle *AH, lclContext *ctx);
static int	_DoDeflate(ArchiveHandle *AH, lclContext *ctx, int flush);

static char *modulename = gettext_noop("custom archiver");



/*
 *	Init routine required by ALL formats. This is a global routine
 *	and should be declared in pg_backup_archiver.h
 *
 *	It's task is to create any extra archive context (using AH->formatData),
 *	and to initialize the supported function pointers.
 *
 *	It should also prepare whatever it's input source is for reading/writing,
 *	and in the case of a read mode connection, it should load the Header & TOC.
 */
void
InitArchiveFmt_Custom(ArchiveHandle *AH)
{
	lclContext *ctx;

	/* Assuming static functions, this can be copied for each format. */
	AH->ArchiveEntryPtr = _ArchiveEntry;
	AH->StartDataPtr = _StartData;
	AH->WriteDataPtr = _WriteData;
	AH->EndDataPtr = _EndData;
	AH->WriteBytePtr = _WriteByte;
	AH->ReadBytePtr = _ReadByte;
	AH->WriteBufPtr = _WriteBuf;
	AH->ReadBufPtr = _ReadBuf;
	AH->ClosePtr = _CloseArchive;
	AH->PrintTocDataPtr = _PrintTocData;
	AH->ReadExtraTocPtr = _ReadExtraToc;
	AH->WriteExtraTocPtr = _WriteExtraToc;
	AH->PrintExtraTocPtr = _PrintExtraToc;

	AH->StartBlobsPtr = _StartBlobs;
	AH->StartBlobPtr = _StartBlob;
	AH->EndBlobPtr = _EndBlob;
	AH->EndBlobsPtr = _EndBlobs;

	/*
	 * Set up some special context used in compressing data.
	 */
	ctx = (lclContext *) calloc(1, sizeof(lclContext));
	if (ctx == NULL)
		die_horribly(AH, modulename, "out of memory\n");
	AH->formatData = (void *) ctx;

	ctx->zp = (z_streamp) malloc(sizeof(z_stream));
	if (ctx->zp == NULL)
		die_horribly(AH, modulename, "out of memory\n");

	/* Initialize LO buffering */
	AH->lo_buf_size = LOBBUFSIZE;
	AH->lo_buf = (void *) malloc(LOBBUFSIZE);
	if (AH->lo_buf == NULL)
		die_horribly(AH, modulename, "out of memory\n");

	/*
	 * zlibOutSize is the buffer size we tell zlib it can output to.  We
	 * actually allocate one extra byte because some routines want to append a
	 * trailing zero byte to the zlib output.  The input buffer is expansible
	 * and is always of size ctx->inSize; zlibInSize is just the initial
	 * default size for it.
	 */
	ctx->zlibOut = (char *) malloc(zlibOutSize + 1);
	ctx->zlibIn = (char *) malloc(zlibInSize);
	ctx->inSize = zlibInSize;
	ctx->filePos = 0;

	if (ctx->zlibOut == NULL || ctx->zlibIn == NULL)
		die_horribly(AH, modulename, "out of memory\n");

	/*
	 * Now open the file
	 */
	if (AH->mode == archModeWrite)
	{
		if (AH->fSpec && strcmp(AH->fSpec, "") != 0)
			AH->FH = fopen(AH->fSpec, PG_BINARY_W);
		else
			AH->FH = stdout;

		if (!AH->FH)
			die_horribly(AH, modulename, "could not open archive file \"%s\": %s\n", AH->fSpec, strerror(errno));

		ctx->hasSeek = checkSeek(AH->FH);
	}
	else
	{
		if (AH->fSpec && strcmp(AH->fSpec, "") != 0)
			AH->FH = fopen(AH->fSpec, PG_BINARY_R);
		else
			AH->FH = stdin;
		if (!AH->FH)
			die_horribly(AH, modulename, "could not open archive file \"%s\": %s\n", AH->fSpec, strerror(errno));

		ctx->hasSeek = checkSeek(AH->FH);

		ReadHead(AH);
		ReadToc(AH);
		ctx->dataStart = _getFilePos(AH, ctx);
	}

}

/*
 * Called by the Archiver when the dumper creates a new TOC entry.
 *
 * Optional.
 *
 * Set up extrac format-related TOC data.
*/
static void
_ArchiveEntry(ArchiveHandle *AH, TocEntry *te)
{
	lclTocEntry *ctx;

	ctx = (lclTocEntry *) calloc(1, sizeof(lclTocEntry));
	if (te->dataDumper)
		ctx->dataState = K_OFFSET_POS_NOT_SET;
	else
		ctx->dataState = K_OFFSET_NO_DATA;

	te->formatData = (void *) ctx;
}

/*
 * Called by the Archiver to save any extra format-related TOC entry
 * data.
 *
 * Optional.
 *
 * Use the Archiver routines to write data - they are non-endian, and
 * maintain other important file information.
 */
static void
_WriteExtraToc(ArchiveHandle *AH, TocEntry *te)
{
	lclTocEntry *ctx = (lclTocEntry *) te->formatData;

	WriteOffset(AH, ctx->dataPos, ctx->dataState);
}

/*
 * Called by the Archiver to read any extra format-related TOC data.
 *
 * Optional.
 *
 * Needs to match the order defined in _WriteExtraToc, and sould also
 * use the Archiver input routines.
 */
static void
_ReadExtraToc(ArchiveHandle *AH, TocEntry *te)
{
	int			junk;
	lclTocEntry *ctx = (lclTocEntry *) te->formatData;

	if (ctx == NULL)
	{
		ctx = (lclTocEntry *) calloc(1, sizeof(lclTocEntry));
		te->formatData = (void *) ctx;
	}

	ctx->dataState = ReadOffset(AH, &(ctx->dataPos));

	/*
	 * Prior to V1.7 (pg7.3), we dumped the data size as an int now we don't
	 * dump it at all.
	 */
	if (AH->version < K_VERS_1_7)
		junk = ReadInt(AH);
}

/*
 * Called by the Archiver when restoring an archive to output a comment
 * that includes useful information about the TOC entry.
 *
 * Optional.
 *
 */
static void
_PrintExtraToc(ArchiveHandle *AH, TocEntry *te)
{
	lclTocEntry *ctx = (lclTocEntry *) te->formatData;

	if (AH->public.verbose)
		ahprintf(AH, "-- Data Pos: " INT64_FORMAT "\n",
				 (int64) ctx->dataPos);
}

/*
 * Called by the archiver when saving TABLE DATA (not schema). This routine
 * should save whatever format-specific information is needed to read
 * the archive back.
 *
 * It is called just prior to the dumper's 'DataDumper' routine being called.
 *
 * Optional, but strongly recommended.
 *
 */
static void
_StartData(ArchiveHandle *AH, TocEntry *te)
{
	lclContext *ctx = (lclContext *) AH->formatData;
	lclTocEntry *tctx = (lclTocEntry *) te->formatData;

	tctx->dataPos = _getFilePos(AH, ctx);
	tctx->dataState = K_OFFSET_POS_SET;

	_WriteByte(AH, BLK_DATA);	/* Block type */
	WriteInt(AH, te->dumpId);	/* For sanity check */

	_StartDataCompressor(AH, te);
}

/*
 * Called by archiver when dumper calls WriteData. This routine is
 * called for both BLOB and TABLE data; it is the responsibility of
 * the format to manage each kind of data using StartBlob/StartData.
 *
 * It should only be called from within a DataDumper routine.
 *
 * Mandatory.
 */
static size_t
_WriteData(ArchiveHandle *AH, const void *data, size_t dLen)
{
	lclContext *ctx = (lclContext *) AH->formatData;
	z_streamp	zp = ctx->zp;

	zp->next_in = (void *) data;
	zp->avail_in = dLen;

	while (zp->avail_in != 0)
	{
		/* printf("Deflating %lu bytes\n", (unsigned long) dLen); */
		_DoDeflate(AH, ctx, 0);
	}
	return dLen;
}

/*
 * Called by the archiver when a dumper's 'DataDumper' routine has
 * finished.
 *
 * Optional.
 *
 */
static void
_EndData(ArchiveHandle *AH, TocEntry *te)
{
/*	lclContext *ctx = (lclContext *) AH->formatData; */
/*	lclTocEntry *tctx = (lclTocEntry *) te->formatData; */

	_EndDataCompressor(AH, te);
}

/*
 * Called by the archiver when starting to save all BLOB DATA (not schema).
 * This routine should save whatever format-specific information is needed
 * to read the BLOBs back into memory.
 *
 * It is called just prior to the dumper's DataDumper routine.
 *
 * Optional, but strongly recommended.
 */
static void
_StartBlobs(ArchiveHandle *AH, TocEntry *te)
{
	lclContext *ctx = (lclContext *) AH->formatData;
	lclTocEntry *tctx = (lclTocEntry *) te->formatData;

	tctx->dataPos = _getFilePos(AH, ctx);
	tctx->dataState = K_OFFSET_POS_SET;

	_WriteByte(AH, BLK_BLOBS);	/* Block type */
	WriteInt(AH, te->dumpId);	/* For sanity check */
}

/*
 * Called by the archiver when the dumper calls StartBlob.
 *
 * Mandatory.
 *
 * Must save the passed OID for retrieval at restore-time.
 */
static void
_StartBlob(ArchiveHandle *AH, TocEntry *te, Oid oid)
{
	if (oid == 0)
		die_horribly(AH, modulename, "invalid OID for large object\n");

	WriteInt(AH, oid);
	_StartDataCompressor(AH, te);
}

/*
 * Called by the archiver when the dumper calls EndBlob.
 *
 * Optional.
 */
static void
_EndBlob(ArchiveHandle *AH, TocEntry *te, Oid oid)
{
	_EndDataCompressor(AH, te);
}

/*
 * Called by the archiver when finishing saving all BLOB DATA.
 *
 * Optional.
 */
static void
_EndBlobs(ArchiveHandle *AH, TocEntry *te)
{
	/* Write out a fake zero OID to mark end-of-blobs. */
	WriteInt(AH, 0);
}

/*
 * Print data for a given TOC entry
 */
static void
_PrintTocData(ArchiveHandle *AH, TocEntry *te, RestoreOptions *ropt)
{
	lclContext *ctx = (lclContext *) AH->formatData;
	int			id;
	lclTocEntry *tctx = (lclTocEntry *) te->formatData;
	int			blkType;
	int			found = 0;

	if (tctx->dataState == K_OFFSET_NO_DATA)
		return;

	if (!ctx->hasSeek || tctx->dataState == K_OFFSET_POS_NOT_SET)
	{
		/* Skip over unnecessary blocks until we get the one we want. */

		found = 0;

		_readBlockHeader(AH, &blkType, &id);

		while (id != te->dumpId)
		{
			if ((TocIDRequired(AH, id, ropt) & REQ_DATA) != 0)
				die_horribly(AH, modulename,
							 "Dumping a specific TOC data block out of order is not supported"
					  " without ID on this input stream (fseek required)\n");

			switch (blkType)
			{
				case BLK_DATA:
					_skipData(AH);
					break;

				case BLK_BLOBS:
					_skipBlobs(AH);
					break;

				default:		/* Always have a default */
					die_horribly(AH, modulename,
								 "unrecognized data block type (%d) while searching archive\n",
								 blkType);
					break;
			}
			_readBlockHeader(AH, &blkType, &id);
		}
	}
	else
	{
		/* Grab it */
		if (fseeko(AH->FH, tctx->dataPos, SEEK_SET) != 0)
			die_horribly(AH, modulename, "error during file seek: %s\n", strerror(errno));

		_readBlockHeader(AH, &blkType, &id);
	}

	/* Are we sane? */
	if (id != te->dumpId)
		die_horribly(AH, modulename, "found unexpected block ID (%d) when reading data -- expected %d\n",
					 id, te->dumpId);

	switch (blkType)
	{
		case BLK_DATA:
			_PrintData(AH);
			break;

		case BLK_BLOBS:
			_LoadBlobs(AH);
			break;

		default:				/* Always have a default */
			die_horribly(AH, modulename, "unrecognized data block type %d while restoring archive\n",
						 blkType);
			break;
	}
}

/*
 * Print data from current file position.
*/
static void
_PrintData(ArchiveHandle *AH)
{
	lclContext *ctx = (lclContext *) AH->formatData;