C++ ReleaseBuffer函数代码示例

/*
 * XLogReadBufferExtended
 *		Read a page during XLOG replay
 *
 * This is functionally comparable to ReadBufferExtended. There's some
 * differences in the behavior wrt. the "mode" argument:
 *
 * In RBM_NORMAL mode, if the page doesn't exist, or contains all-zeroes, we
 * return InvalidBuffer. In this case the caller should silently skip the
 * update on this page. (In this situation, we expect that the page was later
 * dropped or truncated. If we don't see evidence of that later in the WAL
 * sequence, we'll complain at the end of WAL replay.)
 *
 * In RBM_ZERO and RBM_ZERO_ON_ERROR modes, if the page doesn't exist, the
 * relation is extended with all-zeroes pages up to the given block number.
 *
 * In RBM_NORMAL_NO_LOG mode, we return InvalidBuffer if the page doesn't
 * exist, and we don't check for all-zeroes.  Thus, no log entry is made
 * to imply that the page should be dropped or truncated later.
 */
Buffer
XLogReadBufferExtended(RelFileNode rnode, ForkNumber forknum,
					   BlockNumber blkno, ReadBufferMode mode)
{
	BlockNumber lastblock;
	Buffer		buffer;
	SMgrRelation smgr;

	Assert(blkno != P_NEW);

	/* Open the relation at smgr level */
	smgr = smgropen(rnode, InvalidBackendId);

	/*
	 * Create the target file if it doesn't already exist.  This lets us cope
	 * if the replay sequence contains writes to a relation that is later
	 * deleted.  (The original coding of this routine would instead suppress
	 * the writes, but that seems like it risks losing valuable data if the
	 * filesystem loses an inode during a crash.  Better to write the data
	 * until we are actually told to delete the file.)
	 */
	smgrcreate(smgr, forknum, true);

	lastblock = smgrnblocks(smgr, forknum);

	if (blkno < lastblock)
	{
		/* page exists in file */
		buffer = ReadBufferWithoutRelcache(rnode, forknum, blkno,
										   mode, NULL);
	}
	else
	{
		/* hm, page doesn't exist in file */
		if (mode == RBM_NORMAL)
		{
			log_invalid_page(rnode, forknum, blkno, false);
			return InvalidBuffer;
		}
		if (mode == RBM_NORMAL_NO_LOG)
			return InvalidBuffer;
		/* OK to extend the file */
		/* we do this in recovery only - no rel-extension lock needed */
		Assert(InRecovery);
		buffer = InvalidBuffer;
		do
		{
			if (buffer != InvalidBuffer)
				ReleaseBuffer(buffer);
			buffer = ReadBufferWithoutRelcache(rnode, forknum,
											   P_NEW, mode, NULL);
		}
		while (BufferGetBlockNumber(buffer) < blkno);
		/* Handle the corner case that P_NEW returns non-consecutive pages */
		if (BufferGetBlockNumber(buffer) != blkno)
		{
			ReleaseBuffer(buffer);
			buffer = ReadBufferWithoutRelcache(rnode, forknum, blkno,
											   mode, NULL);
		}
	}

	if (mode == RBM_NORMAL)
	{
		/* check that page has been initialized */
		Page		page = (Page) BufferGetPage(buffer);

		/*
		 * We assume that PageIsNew is safe without a lock. During recovery,
		 * there should be no other backends that could modify the buffer at
		 * the same time.
		 */
		if (PageIsNew(page))
		{
			ReleaseBuffer(buffer);
			log_invalid_page(rnode, forknum, blkno, true);
			return InvalidBuffer;
		}
	}

//.........这里部分代码省略.........

/* ------------------------------------------------
 * bt_metap()
 *
 * Get a btree meta-page information
 *
 * Usage: SELECT * FROM bt_metap('t1_pkey')
 * ------------------------------------------------
 */
Datum
bt_metap(PG_FUNCTION_ARGS)
{
	text	   *relname = PG_GETARG_TEXT_P(0);
	Buffer		buffer;

	Relation	rel;
	RangeVar   *relrv;
	Datum		result;

	if (!superuser())
		ereport(ERROR,
				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
				 (errmsg("must be superuser to use pgstattuple functions"))));

	relrv = makeRangeVarFromNameList(textToQualifiedNameList(relname));
	rel = relation_openrv(relrv, AccessShareLock);

	if (!IS_INDEX(rel) || !IS_BTREE(rel))
		elog(ERROR, "bt_metap() can be used only on b-tree index.");

	/*
	 * Reject attempts to read non-local temporary relations; we would
	 * be likely to get wrong data since we have no visibility into the
	 * owning session's local buffers.
	 */
	if (isOtherTempNamespace(RelationGetNamespace(rel)))
		ereport(ERROR,
				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
				 errmsg("cannot access temporary tables of other sessions")));

	buffer = ReadBuffer(rel, 0);

	{
		BTMetaPageData *metad;

		TupleDesc	tupleDesc;
		int			j;
		char	   *values[BTMETAP_NCOLUMNS];
		HeapTuple	tuple;

		Page		page = BufferGetPage(buffer);

		metad = BTPageGetMeta(page);

		tupleDesc = RelationNameGetTupleDesc(BTMETAP_TYPE);

		j = 0;
		values[j] = palloc(32);
		snprintf(values[j++], 32, "%d", metad->btm_magic);
		values[j] = palloc(32);
		snprintf(values[j++], 32, "%d", metad->btm_version);
		values[j] = palloc(32);
		snprintf(values[j++], 32, "%d", metad->btm_root);
		values[j] = palloc(32);
		snprintf(values[j++], 32, "%d", metad->btm_level);
		values[j] = palloc(32);
		snprintf(values[j++], 32, "%d", metad->btm_fastroot);
		values[j] = palloc(32);
		snprintf(values[j++], 32, "%d", metad->btm_fastlevel);

		tuple = BuildTupleFromCStrings(TupleDescGetAttInMetadata(tupleDesc),
									   values);

		result = TupleGetDatum(TupleDescGetSlot(tupleDesc), tuple);
	}

	ReleaseBuffer(buffer);

	relation_close(rel, AccessShareLock);

	PG_RETURN_DATUM(result);
}

/*
 * Get a buffer of the type and parity specified by flags, having at least
 * as much free space as indicated by needSpace.  We use the lastUsedPages
 * cache to assign the same buffer previously requested when possible.
 * The returned buffer is already pinned and exclusive-locked.
 *
 * *isNew is set true if the page was initialized here, false if it was
 * already valid.
 */
Buffer
SpGistGetBuffer(Relation index, int flags, int needSpace, bool *isNew)
{
	SpGistCache *cache = spgGetCache(index);
	SpGistLastUsedPage *lup;

	/* Bail out if even an empty page wouldn't meet the demand */
	if (needSpace > SPGIST_PAGE_CAPACITY)
		elog(ERROR, "desired SPGiST tuple size is too big");

	/*
	 * If possible, increase the space request to include relation's
	 * fillfactor.  This ensures that when we add unrelated tuples to a page,
	 * we try to keep 100-fillfactor% available for adding tuples that are
	 * related to the ones already on it.  But fillfactor mustn't cause an
	 * error for requests that would otherwise be legal.
	 */
	needSpace += RelationGetTargetPageFreeSpace(index,
												SPGIST_DEFAULT_FILLFACTOR);
	needSpace = Min(needSpace, SPGIST_PAGE_CAPACITY);

	/* Get the cache entry for this flags setting */
	lup = GET_LUP(cache, flags);

	/* If we have nothing cached, just turn it over to allocNewBuffer */
	if (lup->blkno == InvalidBlockNumber)
	{
		*isNew = true;
		return allocNewBuffer(index, flags);
	}

	/* fixed pages should never be in cache */
	Assert(!SpGistBlockIsFixed(lup->blkno));

	/* If cached freeSpace isn't enough, don't bother looking at the page */
	if (lup->freeSpace >= needSpace)
	{
		Buffer		buffer;
		Page		page;

		buffer = ReadBuffer(index, lup->blkno);

		if (!ConditionalLockBuffer(buffer))
		{
			/*
			 * buffer is locked by another process, so return a new buffer
			 */
			ReleaseBuffer(buffer);
			*isNew = true;
			return allocNewBuffer(index, flags);
		}

		page = BufferGetPage(buffer);

		if (PageIsNew(page) || SpGistPageIsDeleted(page) || PageIsEmpty(page))
		{
			/* OK to initialize the page */
			uint16		pageflags = 0;

			if (GBUF_REQ_LEAF(flags))
				pageflags |= SPGIST_LEAF;
			if (GBUF_REQ_NULLS(flags))
				pageflags |= SPGIST_NULLS;
			SpGistInitBuffer(buffer, pageflags);
			lup->freeSpace = PageGetExactFreeSpace(page) - needSpace;
			*isNew = true;
			return buffer;
		}

		/*
		 * Check that page is of right type and has enough space.  We must
		 * recheck this since our cache isn't necessarily up to date.
		 */
		if ((GBUF_REQ_LEAF(flags) ? SpGistPageIsLeaf(page) : !SpGistPageIsLeaf(page)) &&
			(GBUF_REQ_NULLS(flags) ? SpGistPageStoresNulls(page) : !SpGistPageStoresNulls(page)))
		{
			int			freeSpace = PageGetExactFreeSpace(page);

			if (freeSpace >= needSpace)
			{
				/* Success, update freespace info and return the buffer */
				lup->freeSpace = freeSpace - needSpace;
				*isNew = false;
				return buffer;
			}
		}

		/*
		 * fallback to allocation of new buffer
		 */
		UnlockReleaseBuffer(buffer);
//.........这里部分代码省略.........

static void PersistentStore_DiagnoseDumpTable(
	PersistentStoreData 		*storeData,
	PersistentStoreSharedData 	*storeSharedData)
{

	if (disable_persistent_diagnostic_dump)
	{
		return;
	}

	MIRROREDLOCK_BUFMGR_DECLARE;

	PersistentStoreScan storeScan;
	ItemPointerData			persistentTid;
	int64					persistentSerialNum;
	Datum					*values;
	BlockNumber				lastDisplayedBlockNum;
	bool					displayedOne;
	BlockNumber				currentBlockNum;

	elog(LOG, 
		 "Diagnostic dump of persistent table ('%s'): maximum in-use serial number " INT64_FORMAT ", maximum free order number " INT64_FORMAT ", free TID %s, maximum known TID %s",
		 storeData->tableName,
		 storeSharedData->maxInUseSerialNum, 
		 storeSharedData->maxFreeOrderNum, 
		 ItemPointerToString(&storeSharedData->freeTid),
		 ItemPointerToString2(&storeSharedData->maxTid));

	values = (Datum*)palloc(storeData->numAttributes * sizeof(Datum));

	PersistentStore_BeginScan(
						storeData,
						storeSharedData,
						&storeScan);

	lastDisplayedBlockNum = 0;
	displayedOne = false;
	while (PersistentStore_GetNext(
							&storeScan,
							values,
							&persistentTid,
							&persistentSerialNum))
	{
		/*
		 * Use the BlockIdGetBlockNumber routine because ItemPointerGetBlockNumber 
		 * asserts for valid TID.
		 */
		currentBlockNum = BlockIdGetBlockNumber(&persistentTid.ip_blkid);
		if (!displayedOne || currentBlockNum != lastDisplayedBlockNum)
		{
			Buffer		buffer;
			PageHeader	page;
			XLogRecPtr	lsn;

			/*
			 * Fetch the block and display the LSN.
			 */
			
			// -------- MirroredLock ----------
			MIRROREDLOCK_BUFMGR_LOCK;
			
			buffer = ReadBuffer(
							storeScan.persistentRel,
							currentBlockNum);

			page = (PageHeader) BufferGetPage(buffer);
			lsn = PageGetLSN(page);
			ReleaseBuffer(buffer);

			MIRROREDLOCK_BUFMGR_UNLOCK;
			// -------- MirroredLock ----------

			elog(LOG, "Diagnostic LSN %s of page %u",
				 XLogLocationToString(&lsn),
				 currentBlockNum);

			lastDisplayedBlockNum = currentBlockNum;
			displayedOne = true;
		}

		/*
		 * Display the persistent tuple.
		 */
		(*storeData->printTupleCallback)(
									LOG,
									"DIAGNOSE",
									&persistentTid,
									values);
	}
	
	PersistentStore_EndScan(&storeScan);

	pfree(values);
}

/* -----------------------------------------------
 * bt_page()
 *
 * Usage: SELECT * FROM bt_page('t1_pkey', 0);
 * -----------------------------------------------
 */
Datum
bt_page_stats(PG_FUNCTION_ARGS)
{
	text	   *relname = PG_GETARG_TEXT_P(0);
	uint32		blkno = PG_GETARG_UINT32(1);
	Buffer		buffer;

	Relation	rel;
	RangeVar   *relrv;
	Datum		result;

	if (!superuser())
		ereport(ERROR,
				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
				 (errmsg("must be superuser to use pgstattuple functions"))));

	relrv = makeRangeVarFromNameList(textToQualifiedNameList(relname));
	rel = relation_openrv(relrv, AccessShareLock);

	if (!IS_INDEX(rel) || !IS_BTREE(rel))
		elog(ERROR, "bt_page_stats() can be used only on b-tree index.");

	/*
	 * Reject attempts to read non-local temporary relations; we would
	 * be likely to get wrong data since we have no visibility into the
	 * owning session's local buffers.
	 */
	if (isOtherTempNamespace(RelationGetNamespace(rel)))
		ereport(ERROR,
				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
				 errmsg("cannot access temporary tables of other sessions")));

	if (blkno == 0)
		elog(ERROR, "Block 0 is a meta page.");

	CHECK_RELATION_BLOCK_RANGE(rel, blkno);

	buffer = ReadBuffer(rel, blkno);

	{
		HeapTuple	tuple;
		TupleDesc	tupleDesc;
		int			j;
		char	   *values[BTPAGESTATS_NCOLUMNS];

		BTPageStat	stat;

		GetBTPageStatistics(blkno, buffer, &stat);

		tupleDesc = RelationNameGetTupleDesc(BTPAGESTATS_TYPE);

		j = 0;
		values[j] = palloc(32);
		snprintf(values[j++], 32, "%d", stat.blkno);

		values[j] = palloc(32);
		snprintf(values[j++], 32, "%c", stat.type);
		values[j] = palloc(32);
		snprintf(values[j++], 32, "%d", stat.live_items);
		values[j] = palloc(32);
		snprintf(values[j++], 32, "%d", stat.dead_items);
		values[j] = palloc(32);
		snprintf(values[j++], 32, "%d", stat.avg_item_size);
		values[j] = palloc(32);
		snprintf(values[j++], 32, "%d", stat.page_size);
		values[j] = palloc(32);
		snprintf(values[j++], 32, "%d", stat.free_size);
		values[j] = palloc(32);
		snprintf(values[j++], 32, "%d", stat.btpo_prev);
		values[j] = palloc(32);
		snprintf(values[j++], 32, "%d", stat.btpo_next);

		values[j] = palloc(32);
		if (stat.type == 'd')
			snprintf(values[j++], 32, "%d", stat.btpo.xact);
		else
			snprintf(values[j++], 32, "%d", stat.btpo.level);

		values[j] = palloc(32);
		snprintf(values[j++], 32, "%d", stat.btpo_flags);

		tuple = BuildTupleFromCStrings(TupleDescGetAttInMetadata(tupleDesc),
									   values);

		result = TupleGetDatum(TupleDescGetSlot(tupleDesc), tuple);
	}

	ReleaseBuffer(buffer);

	relation_close(rel, AccessShareLock);

	PG_RETURN_DATUM(result);
}

//.........这里部分代码省略.........
		 * done a bit of extra work for no gain, but there's no real harm
		 * done.
		 */
		if (otherBuffer == InvalidBuffer || buffer <= otherBuffer)
			GetVisibilityMapPins(relation, buffer, otherBuffer,
								 targetBlock, otherBlock, vmbuffer,
								 vmbuffer_other);
		else
			GetVisibilityMapPins(relation, otherBuffer, buffer,
								 otherBlock, targetBlock, vmbuffer_other,
								 vmbuffer);

		/*
		 * Now we can check to see if there's enough free space here. If so,
		 * we're done.
		 */
		page = BufferGetPage(buffer);
		pageFreeSpace = PageGetHeapFreeSpace(page);
		if (len + saveFreeSpace <= pageFreeSpace)
		{
			/* use this page as future insert target, too */
			RelationSetTargetBlock(relation, targetBlock);
			return buffer;
		}

		/*
		 * Not enough space, so we must give up our page locks and pin (if
		 * any) and prepare to look elsewhere.	We don't care which order we
		 * unlock the two buffers in, so this can be slightly simpler than the
		 * code above.
		 */
		LockBuffer(buffer, BUFFER_LOCK_UNLOCK);
		if (otherBuffer == InvalidBuffer)
			ReleaseBuffer(buffer);
		else if (otherBlock != targetBlock)
		{
			LockBuffer(otherBuffer, BUFFER_LOCK_UNLOCK);
			ReleaseBuffer(buffer);
		}

		/* Without FSM, always fall out of the loop and extend */
		if (!use_fsm)
			break;

		/*
		 * Update FSM as to condition of this page, and ask for another page
		 * to try.
		 */
		targetBlock = RecordAndGetPageWithFreeSpace(relation,
													targetBlock,
													pageFreeSpace,
													len + saveFreeSpace);
	}

	/*
	 * Have to extend the relation.
	 *
	 * We have to use a lock to ensure no one else is extending the rel at the
	 * same time, else we will both try to initialize the same new page.  We
	 * can skip locking for new or temp relations, however, since no one else
	 * could be accessing them.
	 */
	needLock = !RELATION_IS_LOCAL(relation);

	if (needLock)
		LockRelationForExtension(relation, ExclusiveLock);

void PersistentStore_ReplaceTuple(
	PersistentStoreData 		*storeData,
	PersistentStoreSharedData 	*storeSharedData,
	ItemPointer 			persistentTid,
				/* TID of the stored tuple. */
	HeapTuple				tuple,
	Datum					*newValues,
	bool					*replaces,
	bool					flushToXLog)
				/* When true, the XLOG record for this change will be flushed to disk. */
{
	Relation	persistentRel;
	bool 		*nulls;
	HeapTuple	replacementTuple = NULL;
	XLogRecPtr 	xlogUpdateEndLoc;
	
#ifdef USE_ASSERT_CHECKING
	if (storeSharedData == NULL ||
		!PersistentStoreSharedData_EyecatcherIsValid(storeSharedData))
		elog(ERROR, "Persistent store shared-memory not valid");
#endif
	
	if (Debug_persistent_store_print)
		elog(PersistentStore_DebugPrintLevel(), 
			 "PersistentStore_ReplaceTuple: Going to replace set of columns in tuple at TID %s ('%s', shared data %p)",
			 ItemPointerToString(persistentTid),
			 storeData->tableName,
			 storeSharedData);

	persistentRel = (*storeData->openRel)();

	/*
	 * In order to keep the tuples the exact same size to enable direct reuse of
	 * free tuples, we do not use NULLs.
	 */
	nulls = (bool*)palloc0(storeData->numAttributes * sizeof(bool));
		
	/*
	 * Modify the tuple.
	 */
	replacementTuple = heap_modify_tuple(tuple, persistentRel->rd_att, 
										 newValues, nulls, replaces);

	replacementTuple->t_self = *persistentTid;
		
	frozen_heap_inplace_update(persistentRel, replacementTuple);

	/*
	 * Return the XLOG location of the UPDATE tuple's XLOG record.
	 */
	xlogUpdateEndLoc = XLogLastInsertEndLoc();

	heap_freetuple(replacementTuple);
	pfree(nulls);

	if (Debug_persistent_store_print)
	{
		Datum 			*readValues;
		bool			*readNulls;
		HeapTupleData 	readTuple;
		Buffer			buffer;
		HeapTuple		readTupleCopy;
		
		elog(PersistentStore_DebugPrintLevel(), 
			 "PersistentStore_ReplaceTuple: Replaced set of columns in tuple at TID %s ('%s')",
			 ItemPointerToString(persistentTid),
			 storeData->tableName);
		
		readValues = (Datum*)palloc(storeData->numAttributes * sizeof(Datum));
		readNulls = (bool*)palloc(storeData->numAttributes * sizeof(bool));

		readTuple.t_self = *persistentTid;
		
		if (!heap_fetch(persistentRel, SnapshotAny,
						&readTuple, &buffer, false, NULL))
		{
			elog(ERROR, "Failed to fetch persistent tuple at %s ('%s')",
				 ItemPointerToString(&readTuple.t_self),
				 storeData->tableName);
		}
		
		
		readTupleCopy = heaptuple_copy_to(&readTuple, NULL, NULL);
		
		ReleaseBuffer(buffer);
		
		heap_deform_tuple(readTupleCopy, persistentRel->rd_att, readValues, readNulls);
		
		(*storeData->printTupleCallback)(
									PersistentStore_DebugPrintLevel(),
									"STORE REPLACED TUPLE",
									persistentTid,
									readValues);

		heap_freetuple(readTupleCopy);
		pfree(readValues);
		pfree(readNulls);
	}

	(*storeData->closeRel)(persistentRel);
//.........这里部分代码省略.........

/*
 *	_hash_dropbuf() -- release an unlocked buffer.
 *
 * This is used to unpin a buffer on which we hold no lock.
 */
void
_hash_dropbuf(Relation rel, Buffer buf)
{
	ReleaseBuffer(buf);
}

STDMETHODIMP CDecWMV9::ProcessOutput()
{
  HRESULT hr = S_OK;
  DWORD dwStatus = 0;

  BYTE *pBuffer = GetBuffer(m_pRawBufferSize);
  CMediaBuffer *pOutBuffer = new CMediaBuffer(pBuffer, m_pRawBufferSize, true);
  pOutBuffer->SetLength(0);

  DMO_OUTPUT_DATA_BUFFER OutputBufferStructs[1];
  memset(&OutputBufferStructs[0], 0, sizeof(DMO_OUTPUT_DATA_BUFFER));
  OutputBufferStructs[0].pBuffer  = pOutBuffer;

  hr = m_pDMO->ProcessOutput(0, 1, OutputBufferStructs, &dwStatus);
  if (FAILED(hr)) {
    ReleaseBuffer(pBuffer);
    DbgLog((LOG_TRACE, 10, L"-> ProcessOutput failed with hr: %x", hr));
    return S_FALSE;
  }
  if (hr == S_FALSE) {
    ReleaseBuffer(pBuffer);
    return S_FALSE;
  }

  LAVFrame *pFrame = nullptr;
  AllocateFrame(&pFrame);

  BITMAPINFOHEADER *pBMI = nullptr;
  videoFormatTypeHandler(mtOut, &pBMI);
  pFrame->width     = pBMI->biWidth;
  pFrame->height    = pBMI->biHeight;
  pFrame->format    = m_OutPixFmt;
  pFrame->key_frame = (OutputBufferStructs[0].dwStatus & DMO_OUTPUT_DATA_BUFFERF_SYNCPOINT);

  AVRational display_aspect_ratio;
  int64_t num = (int64_t)m_StreamAR.num * pBMI->biWidth;
  int64_t den = (int64_t)m_StreamAR.den * pBMI->biHeight;
  av_reduce(&display_aspect_ratio.num, &display_aspect_ratio.den, num, den, INT_MAX);

  BYTE contentType = 0;
  DWORD dwPropSize = 1;
  pOutBuffer->GetProperty(WM_SampleExtensionGUID_ContentType, &contentType, &dwPropSize);
  pFrame->interlaced = !!(contentType & WM_CT_INTERLACED);
  pFrame->repeat     = !!(contentType & WM_CT_REPEAT_FIRST_FIELD);

  LAVDeintFieldOrder fo = m_pSettings->GetDeintFieldOrder();
  pFrame->tff           = (fo == DeintFieldOrder_Auto) ? !!(contentType & WM_CT_TOP_FIELD_FIRST) : (fo == DeintFieldOrder_TopFieldFirst);

  if (pFrame->interlaced && !m_bInterlaced)
    m_bInterlaced = TRUE;

  pFrame->interlaced = (pFrame->interlaced || (m_bInterlaced && m_pSettings->GetDeinterlacingMode() == DeintMode_Aggressive) || m_pSettings->GetDeinterlacingMode() == DeintMode_Force) && !(m_pSettings->GetDeinterlacingMode() == DeintMode_Disable);

  if (m_bManualReorder) {
    if (!m_timestampQueue.empty()) {
      pFrame->rtStart = m_timestampQueue.front();
      m_timestampQueue.pop();
      if (OutputBufferStructs[0].dwStatus & DMO_OUTPUT_DATA_BUFFERF_TIMELENGTH) {
        pFrame->rtStop = pFrame->rtStart + OutputBufferStructs[0].rtTimelength;
      }
    }
  } else {
    if (OutputBufferStructs[0].dwStatus & DMO_OUTPUT_DATA_BUFFERF_TIME) {
      pFrame->rtStart = OutputBufferStructs[0].rtTimestamp;
      if (OutputBufferStructs[0].dwStatus & DMO_OUTPUT_DATA_BUFFERF_TIMELENGTH) {
        pFrame->rtStop = pFrame->rtStart + OutputBufferStructs[0].rtTimelength;
      }
    }
  }

  // Check alignment
  // If not properly aligned, we need to make the data aligned.
  int alignment = (m_OutPixFmt == LAVPixFmt_NV12) ? 16 : 32;
  if ((pFrame->width % alignment) != 0) {
    AllocLAVFrameBuffers(pFrame);
    size_t ySize = pFrame->width * pFrame->height;
    memcpy_plane(pFrame->data[0], pBuffer, pFrame->width, pFrame->stride[0], pFrame->height);
    if (m_OutPixFmt == LAVPixFmt_NV12) {
      memcpy_plane(pFrame->data[1], pBuffer+ySize, pFrame->width, pFrame->stride[1], pFrame->height / 2);
    } else if (m_OutPixFmt == LAVPixFmt_YUV420) {
      size_t uvSize = ySize / 4;
      memcpy_plane(pFrame->data[2], pBuffer+ySize, pFrame->width / 2, pFrame->stride[2], pFrame->height / 2);
      memcpy_plane(pFrame->data[1], pBuffer+ySize+uvSize, pFrame->width / 2, pFrame->stride[1], pFrame->height / 2);
    }
    ReleaseBuffer(pBuffer);
  } else {
    if (m_OutPixFmt == LAVPixFmt_NV12) {
      pFrame->data[0] = pBuffer;
      pFrame->data[1] = pBuffer + pFrame->width * pFrame->height;
      pFrame->stride[0] = pFrame->stride[1] = pFrame->width;
    } else if (m_OutPixFmt == LAVPixFmt_YUV420) {
      pFrame->data[0] = pBuffer;
      pFrame->data[2] = pBuffer + pFrame->width * pFrame->height;
      pFrame->data[1] = pFrame->data[2] + (pFrame->width / 2) * (pFrame->height / 2);
      pFrame->stride[0] = pFrame->width;
      pFrame->stride[1] = pFrame->stride[2] = pFrame->width / 2;
    }
    pFrame->destruct = wmv9_buffer_destruct;
    pFrame->priv_data = this;
  }
//.........这里部分代码省略.........

/*
 * Search the relation 'rel' for tuple using the index.
 *
 * If a matching tuple is found, lock it with lockmode, fill the slot with its
 * contents, and return true.  Return false otherwise.
 */
bool
RelationFindReplTupleByIndex(Relation rel, Oid idxoid,
							 LockTupleMode lockmode,
							 TupleTableSlot *searchslot,
							 TupleTableSlot *outslot)
{
	HeapTuple	scantuple;
	ScanKeyData skey[INDEX_MAX_KEYS];
	IndexScanDesc scan;
	SnapshotData snap;
	TransactionId xwait;
	Relation	idxrel;
	bool		found;

	/* Open the index. */
	idxrel = index_open(idxoid, RowExclusiveLock);

	/* Start an index scan. */
	InitDirtySnapshot(snap);
	scan = index_beginscan(rel, idxrel, &snap,
						   IndexRelationGetNumberOfKeyAttributes(idxrel),
						   0);

	/* Build scan key. */
	build_replindex_scan_key(skey, rel, idxrel, searchslot);

retry:
	found = false;

	index_rescan(scan, skey, IndexRelationGetNumberOfKeyAttributes(idxrel), NULL, 0);

	/* Try to find the tuple */
	if ((scantuple = index_getnext(scan, ForwardScanDirection)) != NULL)
	{
		found = true;
		ExecStoreTuple(scantuple, outslot, InvalidBuffer, false);
		ExecMaterializeSlot(outslot);

		xwait = TransactionIdIsValid(snap.xmin) ?
			snap.xmin : snap.xmax;

		/*
		 * If the tuple is locked, wait for locking transaction to finish and
		 * retry.
		 */
		if (TransactionIdIsValid(xwait))
		{
			XactLockTableWait(xwait, NULL, NULL, XLTW_None);
			goto retry;
		}
	}

	/* Found tuple, try to lock it in the lockmode. */
	if (found)
	{
		Buffer		buf;
		HeapUpdateFailureData hufd;
		HTSU_Result res;
		HeapTupleData locktup;

		ItemPointerCopy(&outslot->tts_tuple->t_self, &locktup.t_self);

		PushActiveSnapshot(GetLatestSnapshot());

		res = heap_lock_tuple(rel, &locktup, GetCurrentCommandId(false),
							  lockmode,
							  LockWaitBlock,
							  false /* don't follow updates */ ,
							  &buf, &hufd);
		/* the tuple slot already has the buffer pinned */
		ReleaseBuffer(buf);

		PopActiveSnapshot();

		switch (res)
		{
			case HeapTupleMayBeUpdated:
				break;
			case HeapTupleUpdated:
				/* XXX: Improve handling here */
				if (ItemPointerIndicatesMovedPartitions(&hufd.ctid))
					ereport(LOG,
							(errcode(ERRCODE_T_R_SERIALIZATION_FAILURE),
							 errmsg("tuple to be locked was already moved to another partition due to concurrent update, retrying")));
				else
					ereport(LOG,
							(errcode(ERRCODE_T_R_SERIALIZATION_FAILURE),
							 errmsg("concurrent update, retrying")));
				goto retry;
			case HeapTupleInvisible:
				elog(ERROR, "attempted to lock invisible tuple");
			default:
				elog(ERROR, "unexpected heap_lock_tuple status: %u", res);
				break;
//.........这里部分代码省略.........

/*
 * Search the relation 'rel' for tuple using the sequential scan.
 *
 * If a matching tuple is found, lock it with lockmode, fill the slot with its
 * contents, and return true.  Return false otherwise.
 *
 * Note that this stops on the first matching tuple.
 *
 * This can obviously be quite slow on tables that have more than few rows.
 */
bool
RelationFindReplTupleSeq(Relation rel, LockTupleMode lockmode,
						 TupleTableSlot *searchslot, TupleTableSlot *outslot)
{
	HeapTuple	scantuple;
	HeapScanDesc scan;
	SnapshotData snap;
	TransactionId xwait;
	bool		found;
	TupleDesc	desc = RelationGetDescr(rel);

	Assert(equalTupleDescs(desc, outslot->tts_tupleDescriptor));

	/* Start a heap scan. */
	InitDirtySnapshot(snap);
	scan = heap_beginscan(rel, &snap, 0, NULL);

retry:
	found = false;

	heap_rescan(scan, NULL);

	/* Try to find the tuple */
	while ((scantuple = heap_getnext(scan, ForwardScanDirection)) != NULL)
	{
		if (!tuple_equals_slot(desc, scantuple, searchslot))
			continue;

		found = true;
		ExecStoreTuple(scantuple, outslot, InvalidBuffer, false);
		ExecMaterializeSlot(outslot);

		xwait = TransactionIdIsValid(snap.xmin) ?
			snap.xmin : snap.xmax;

		/*
		 * If the tuple is locked, wait for locking transaction to finish and
		 * retry.
		 */
		if (TransactionIdIsValid(xwait))
		{
			XactLockTableWait(xwait, NULL, NULL, XLTW_None);
			goto retry;
		}
	}

	/* Found tuple, try to lock it in the lockmode. */
	if (found)
	{
		Buffer		buf;
		HeapUpdateFailureData hufd;
		HTSU_Result res;
		HeapTupleData locktup;

		ItemPointerCopy(&outslot->tts_tuple->t_self, &locktup.t_self);

		PushActiveSnapshot(GetLatestSnapshot());

		res = heap_lock_tuple(rel, &locktup, GetCurrentCommandId(false),
							  lockmode,
							  LockWaitBlock,
							  false /* don't follow updates */ ,
							  &buf, &hufd);
		/* the tuple slot already has the buffer pinned */
		ReleaseBuffer(buf);

		PopActiveSnapshot();

		switch (res)
		{
			case HeapTupleMayBeUpdated:
				break;
			case HeapTupleUpdated:
				/* XXX: Improve handling here */
				if (ItemPointerIndicatesMovedPartitions(&hufd.ctid))
					ereport(LOG,
							(errcode(ERRCODE_T_R_SERIALIZATION_FAILURE),
							 errmsg("tuple to be locked was already moved to another partition due to concurrent update, retrying")));
				else
					ereport(LOG,
							(errcode(ERRCODE_T_R_SERIALIZATION_FAILURE),
							 errmsg("concurrent update, retrying")));
				goto retry;
			case HeapTupleInvisible:
				elog(ERROR, "attempted to lock invisible tuple");
			default:
				elog(ERROR, "unexpected heap_lock_tuple status: %u", res);
				break;
		}
	}
//.........这里部分代码省略.........

void C_TCPServerConnection::run()
{
	assert(m_pMsgConsolePrompter);
	m_pMsgConsolePrompter->PromptMessageLineBy(_T("TCP_CONNECTION_0"));

	socket().setReceiveTimeout(Poco::Timespan(90,0));

	try
	{
		char* pszCmdBuffer = NULL;

		while (true)
		{
			long nCmdLen = 0;
			recvData(socket(), &pszCmdBuffer, nCmdLen);

			if (nCmdLen == 0)
			{
				if (!m_szClientID.empty())
				{
					C_NetCmdLogOff logOff;
					logOff.HandleRequest(socket(), NULL, m_DBOperate, m_szClientID.c_str());
				}

				m_pMsgConsolePrompter->PromptMessageLineBy(_T("TCP_CONNECTION_1"));
				break;
			}

			if (nCmdLen > 0)
			{
				C_NetCommandDecomposer netCmdDecomposer;
				if(!netCmdDecomposer.Decompose(pszCmdBuffer))
				{
					ReleaseBuffer(&pszCmdBuffer);
					continue;
				}

				tstring szCmdName = netCmdDecomposer.GetCmdName().c_str();
				C_NetCommand* pRequestCmd = m_NetCmder.CreateCommand(szCmdName.c_str(), netCmdDecomposer.GetCmdType().c_str());
				
				if(pRequestCmd == NULL)
				{
					ReleaseBuffer(&pszCmdBuffer);
					continue;
				}

				if(szCmdName ==_T("log on") || szCmdName ==_T("log off") || szCmdName == _T("fetch channels") || szCmdName == _T("fetch content"))
				{
					if(!m_bLogOn)
					{	
						C_NetCmdLogOn *pLogOn = dynamic_cast<C_NetCmdLogOn*>(pRequestCmd);
						if(pLogOn == NULL)
							continue;

						tstring szMac = netCmdDecomposer.GetCmdPara(_T("id"));
						if( pLogOn->HandleRequest(socket(), pszCmdBuffer, m_DBOperate, szMac.c_str()) )
						{
							m_szClientID = szMac;
							m_bLogOn = true;
							ReleaseBuffer(&pszCmdBuffer);
							pLogOn->Release();
							C_AreaEvent::GetInstance()->PushEvent(socket(), szMac.c_str());
						}
						continue;
					}
				}
				
				pRequestCmd->HandleRequest(socket(), pszCmdBuffer, m_DBOperate, m_szClientID.c_str());
				pRequestCmd->Release();
				ReleaseBuffer(&pszCmdBuffer);
			}
		}
	}
	catch (Poco::Exception& exc)
	{
		if (!m_szClientID.empty())
		{
			C_NetCmdLogOff logOff;
			logOff.HandleRequest(socket(), NULL, m_DBOperate, m_szClientID.c_str());
		}
		m_pMsgConsolePrompter->PromptMessageLineBy(_T("TCP_CONNECTION_2"), exc.what());
		return;
	}
}

/*
 * workhorse
 */
static bytea *
get_raw_page_internal(text *relname, ForkNumber forknum, BlockNumber blkno)
{
	bytea	   *raw_page;
	RangeVar   *relrv;
	Relation	rel;
	char	   *raw_page_data;
	Buffer		buf;

	if (!superuser())
		ereport(ERROR,
				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
				 (errmsg("must be superuser to use raw functions"))));

	relrv = makeRangeVarFromNameList(textToQualifiedNameList(relname));
	rel = relation_openrv(relrv, AccessShareLock);

	/* Check that this relation has storage */
	if (rel->rd_rel->relkind == RELKIND_VIEW)
		ereport(ERROR,
				(errcode(ERRCODE_WRONG_OBJECT_TYPE),
				 errmsg("cannot get raw page from view \"%s\"",
						RelationGetRelationName(rel))));
	if (rel->rd_rel->relkind == RELKIND_COMPOSITE_TYPE)
		ereport(ERROR,
				(errcode(ERRCODE_WRONG_OBJECT_TYPE),
				 errmsg("cannot get raw page from composite type \"%s\"",
						RelationGetRelationName(rel))));

	/*
	 * Reject attempts to read non-local temporary relations; we would be
	 * likely to get wrong data since we have no visibility into the owning
	 * session's local buffers.
	 */
	if (RELATION_IS_OTHER_TEMP(rel))
		ereport(ERROR,
				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
				 errmsg("cannot access temporary tables of other sessions")));

	if (blkno >= RelationGetNumberOfBlocks(rel))
		elog(ERROR, "block number %u is out of range for relation \"%s\"",
			 blkno, RelationGetRelationName(rel));

	/* Initialize buffer to copy to */
	raw_page = (bytea *) palloc(BLCKSZ + VARHDRSZ);
	SET_VARSIZE(raw_page, BLCKSZ + VARHDRSZ);
	raw_page_data = VARDATA(raw_page);

	/* Take a verbatim copy of the page */

	buf = ReadBufferExtended(rel, forknum, blkno, RBM_NORMAL, NULL);
	LockBuffer(buf, BUFFER_LOCK_SHARE);

	memcpy(raw_page_data, BufferGetPage(buf), BLCKSZ);

	LockBuffer(buf, BUFFER_LOCK_UNLOCK);
	ReleaseBuffer(buf);

	relation_close(rel, AccessShareLock);

	return raw_page;
}

//.........这里部分代码省略.........
	rel = relation_open(relOid, AccessShareLock);
	aclresult = pg_class_aclcheck(relOid, GetUserId(), ACL_SELECT);
	if (aclresult != ACLCHECK_OK)
		aclcheck_error(aclresult, ACL_KIND_CLASS, get_rel_name(relOid));

	/* Check that the fork exists. */
	RelationOpenSmgr(rel);
	if (!smgrexists(rel->rd_smgr, forkNumber))
		ereport(ERROR,
				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
				 errmsg("fork \"%s\" does not exist for this relation",
						forkString)));

	/* Validate block numbers, or handle nulls. */
	nblocks = RelationGetNumberOfBlocksInFork(rel, forkNumber);
	if (PG_ARGISNULL(3))
		first_block = 0;
	else
	{
		first_block = PG_GETARG_INT64(3);
		if (first_block < 0 || first_block >= nblocks)
			ereport(ERROR,
					(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
					 errmsg("starting block number must be between 0 and " INT64_FORMAT,
							nblocks - 1)));
	}
	if (PG_ARGISNULL(4))
		last_block = nblocks - 1;
	else
	{
		last_block = PG_GETARG_INT64(4);
		if (last_block < 0 || last_block >= nblocks)
			ereport(ERROR,
					(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
			errmsg("ending block number must be between 0 and " INT64_FORMAT,
				   nblocks - 1)));
	}

	/* Now we're ready to do the real work. */
	if (ptype == PREWARM_PREFETCH)
	{
#ifdef USE_PREFETCH

		/*
		 * In prefetch mode, we just hint the OS to read the blocks, but we
		 * don't know whether it really does it, and we don't wait for it to
		 * finish.
		 *
		 * It would probably be better to pass our prefetch requests in chunks
		 * of a megabyte or maybe even a whole segment at a time, but there's
		 * no practical way to do that at present without a gross modularity
		 * violation, so we just do this.
		 */
		for (block = first_block; block <= last_block; ++block)
		{
			CHECK_FOR_INTERRUPTS();
			PrefetchBuffer(rel, forkNumber, block);
			++blocks_done;
		}
#else
		ereport(ERROR,
				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
				 errmsg("prefetch is not supported by this build")));
#endif
	}
	else if (ptype == PREWARM_READ)
	{
		/*
		 * In read mode, we actually read the blocks, but not into shared
		 * buffers.  This is more portable than prefetch mode (it works
		 * everywhere) and is synchronous.
		 */
		for (block = first_block; block <= last_block; ++block)
		{
			CHECK_FOR_INTERRUPTS();
			smgrread(rel->rd_smgr, forkNumber, block, blockbuffer.data);
			++blocks_done;
		}
	}
	else if (ptype == PREWARM_BUFFER)
	{
		/*
		 * In buffer mode, we actually pull the data into shared_buffers.
		 */
		for (block = first_block; block <= last_block; ++block)
		{
			Buffer		buf;

			CHECK_FOR_INTERRUPTS();
			buf = ReadBufferExtended(rel, forkNumber, block, RBM_NORMAL, NULL);
			ReleaseBuffer(buf);
			++blocks_done;
		}
	}

	/* Close relation, release lock. */
	relation_close(rel, AccessShareLock);

	PG_RETURN_INT64(blocks_done);
}

FarString& FarString::TrimRight()
{
  FarSF::RTrim (GetBuffer());
  ReleaseBuffer();
  return * this;
}