Header And Logo
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#include "postgres.h"#include "access/htup_details.h"#include "funcapi.h"#include "utils/builtins.h"#include "miscadmin.h"
Go to the source code of this file.
Data Structures | |
| struct | heap_page_items_state |
Typedefs | |
| typedef struct heap_page_items_state | heap_page_items_state |
Functions | |
| Datum | heap_page_items (PG_FUNCTION_ARGS) |
| static char * | bits_to_text (bits8 *bits, int len) |
| PG_FUNCTION_INFO_V1 (heap_page_items) | |
| typedef struct heap_page_items_state heap_page_items_state |
| static char* bits_to_text | ( | bits8 * | bits, | |
| int | len | |||
| ) | [static] |
Definition at line 43 of file heapfuncs.c.
Referenced by heap_page_items().
| Datum heap_page_items | ( | PG_FUNCTION_ARGS | ) |
Definition at line 74 of file heapfuncs.c.
References bits_to_text(), FuncCallContext::call_cntr, CStringGetTextDatum, elog, ereport, errcode(), errmsg(), ERROR, get_call_result_type(), heap_form_tuple(), HEAP_HASNULL, HEAP_HASOID, HeapTupleGetDatum, HeapTupleHeaderGetOid, HeapTupleHeaderGetRawCommandId, HeapTupleHeaderGetRawXmax, HeapTupleHeaderGetXmin, i, ItemIdGetFlags, ItemIdGetLength, ItemIdGetOffset, ItemIdHasStorage, FuncCallContext::max_calls, MAXALIGN, MemoryContextSwitchTo(), FuncCallContext::multi_call_memory_ctx, NULL, heap_page_items_state::offset, heap_page_items_state::page, PageGetItem, PageGetItemId, PageGetMaxOffsetNumber, palloc(), PG_GETARG_BYTEA_P, PointerGetDatum, SizeOfPageHeaderData, SRF_FIRSTCALL_INIT, SRF_IS_FIRSTCALL, SRF_PERCALL_SETUP, SRF_RETURN_DONE, SRF_RETURN_NEXT, superuser(), HeapTupleHeaderData::t_bits, HeapTupleHeaderData::t_ctid, HeapTupleHeaderData::t_hoff, HeapTupleHeaderData::t_infomask, HeapTupleHeaderData::t_infomask2, heap_page_items_state::tupd, TYPEFUNC_COMPOSITE, UInt16GetDatum, UInt32GetDatum, UInt8GetDatum, FuncCallContext::user_fctx, values, VARDATA, and VARSIZE.
{
bytea *raw_page = PG_GETARG_BYTEA_P(0);
heap_page_items_state *inter_call_data = NULL;
FuncCallContext *fctx;
int raw_page_size;
if (!superuser())
ereport(ERROR,
(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
(errmsg("must be superuser to use raw page functions"))));
raw_page_size = VARSIZE(raw_page) - VARHDRSZ;
if (SRF_IS_FIRSTCALL())
{
TupleDesc tupdesc;
MemoryContext mctx;
if (raw_page_size < SizeOfPageHeaderData)
ereport(ERROR,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("input page too small (%d bytes)", raw_page_size)));
fctx = SRF_FIRSTCALL_INIT();
mctx = MemoryContextSwitchTo(fctx->multi_call_memory_ctx);
inter_call_data = palloc(sizeof(heap_page_items_state));
/* Build a tuple descriptor for our result type */
if (get_call_result_type(fcinfo, NULL, &tupdesc) != TYPEFUNC_COMPOSITE)
elog(ERROR, "return type must be a row type");
inter_call_data->tupd = tupdesc;
inter_call_data->offset = FirstOffsetNumber;
inter_call_data->page = VARDATA(raw_page);
fctx->max_calls = PageGetMaxOffsetNumber(inter_call_data->page);
fctx->user_fctx = inter_call_data;
MemoryContextSwitchTo(mctx);
}
fctx = SRF_PERCALL_SETUP();
inter_call_data = fctx->user_fctx;
if (fctx->call_cntr < fctx->max_calls)
{
Page page = inter_call_data->page;
HeapTuple resultTuple;
Datum result;
ItemId id;
Datum values[13];
bool nulls[13];
uint16 lp_offset;
uint16 lp_flags;
uint16 lp_len;
memset(nulls, 0, sizeof(nulls));
/* Extract information from the line pointer */
id = PageGetItemId(page, inter_call_data->offset);
lp_offset = ItemIdGetOffset(id);
lp_flags = ItemIdGetFlags(id);
lp_len = ItemIdGetLength(id);
values[0] = UInt16GetDatum(inter_call_data->offset);
values[1] = UInt16GetDatum(lp_offset);
values[2] = UInt16GetDatum(lp_flags);
values[3] = UInt16GetDatum(lp_len);
/*
* We do just enough validity checking to make sure we don't reference
* data outside the page passed to us. The page could be corrupt in
* many other ways, but at least we won't crash.
*/
if (ItemIdHasStorage(id) &&
lp_len >= sizeof(HeapTupleHeader) &&
lp_offset == MAXALIGN(lp_offset) &&
lp_offset + lp_len <= raw_page_size)
{
HeapTupleHeader tuphdr;
int bits_len;
/* Extract information from the tuple header */
tuphdr = (HeapTupleHeader) PageGetItem(page, id);
values[4] = UInt32GetDatum(HeapTupleHeaderGetXmin(tuphdr));
values[5] = UInt32GetDatum(HeapTupleHeaderGetRawXmax(tuphdr));
values[6] = UInt32GetDatum(HeapTupleHeaderGetRawCommandId(tuphdr)); /* shared with xvac */
values[7] = PointerGetDatum(&tuphdr->t_ctid);
values[8] = UInt32GetDatum(tuphdr->t_infomask2);
values[9] = UInt32GetDatum(tuphdr->t_infomask);
values[10] = UInt8GetDatum(tuphdr->t_hoff);
/*
* We already checked that the item as is completely within the
* raw page passed to us, with the length given in the line
* pointer.. Let's check that t_hoff doesn't point over lp_len,
* before using it to access t_bits and oid.
*/
if (tuphdr->t_hoff >= sizeof(HeapTupleHeader) &&
tuphdr->t_hoff <= lp_len)
{
if (tuphdr->t_infomask & HEAP_HASNULL)
{
bits_len = tuphdr->t_hoff -
(((char *) tuphdr->t_bits) -((char *) tuphdr));
values[11] = CStringGetTextDatum(
bits_to_text(tuphdr->t_bits, bits_len * 8));
}
else
nulls[11] = true;
if (tuphdr->t_infomask & HEAP_HASOID)
values[12] = HeapTupleHeaderGetOid(tuphdr);
else
nulls[12] = true;
}
else
{
nulls[11] = true;
nulls[12] = true;
}
}
else
{
/*
* The line pointer is not used, or it's invalid. Set the rest of
* the fields to NULL
*/
int i;
for (i = 4; i <= 12; i++)
nulls[i] = true;
}
/* Build and return the result tuple. */
resultTuple = heap_form_tuple(inter_call_data->tupd, values, nulls);
result = HeapTupleGetDatum(resultTuple);
inter_call_data->offset++;
SRF_RETURN_NEXT(fctx, result);
}
else
SRF_RETURN_DONE(fctx);
}
| PG_FUNCTION_INFO_V1 | ( | heap_page_items | ) |
1.7.1