Method PhysHdr

src/jrd/CryptoManager.cpp:195–274

	{
	public:
		explicit PhysHdr(Jrd::thread_db* tdbb)
		{
			// Can't use CCH_fetch_page() here cause it will cause infinite recursion

			Jrd::Database* dbb = tdbb->getDatabase();
			Jrd::BufferControl* bcb = dbb->dbb_bcb;
			Jrd::BufferDesc bdb(bcb);
			bdb.bdb_page = Jrd::HEADER_PAGE_NUMBER;

			UCHAR* h = FB_NEW_POOL(*MemoryPool::getContextPool()) UCHAR[dbb->dbb_page_size + dbb->getIOBlockSize()];
			buffer.reset(h);
			h = FB_ALIGN(h, dbb->getIOBlockSize());
			bdb.bdb_buffer = (Ods::pag*) h;

			Jrd::FbStatusVector* const status = tdbb->tdbb_status_vector;

			Ods::pag* page = bdb.bdb_buffer;

			Jrd::PageSpace* pageSpace = dbb->dbb_page_manager.findPageSpace(Jrd::DB_PAGE_SPACE);
			fb_assert(pageSpace);

			Jrd::jrd_file* file = pageSpace->file;

			Jrd::BackupManager::StateReadGuard stateGuard(tdbb);
			Jrd::BackupManager* bm = dbb->dbb_backup_manager;
			int bak_state = bm->getState();

			fb_assert(bak_state != Ods::hdr_nbak_unknown);

			ULONG diff_page = 0;
			if (bak_state != Ods::hdr_nbak_normal)
				diff_page = bm->getPageIndex(tdbb, bdb.bdb_page.getPageNum());

			bool readPageAsNormal = false;
			if (bak_state == Ods::hdr_nbak_normal || !diff_page)
				readPageAsNormal = true;
			else
			{
				if (!bm->readDifference(tdbb, diff_page, page))
				{
					if (page->pag_type == 0 && page->pag_generation == 0 && page->pag_scn == 0)
					{
						// We encountered a page which was allocated, but never written to the
						// difference file. In this case we try to read the page from database. With
						// this approach if the page was old we get it from DISK, and if the page
						// was new IO error (EOF) or BUGCHECK (checksum error) will be the result.
						// Engine is not supposed to read a page which was never written unless
						// this is a merge process.
						readPageAsNormal = true;
					}
					else
						ERR_punt();
				}
			}

			if (readPageAsNormal)
			{
				// Read page from disk as normal