Method callback

src/jrd/cch.cpp:960–986

		{ }

		bool callback(thread_db* tdbb, FbStatusVector* status, Ods::pag* page)
		{
			Database *dbb = tdbb->getDatabase();
			int retryCount = 0;

			while (!PIO_read(tdbb, file, bdb, page, status))
	 		{
				if (isTempPage || !read_shadow)
					return false;

				if (!CCH_rollover_to_shadow(tdbb, dbb, file, false))
 					return false;

				if (file != pageSpace->file)
					file = pageSpace->file;
				else
				{
					if (retryCount++ == 3)
					{
						gds__log("IO error loop Unwind to avoid a hang\n");
						return false;
					}
				}
 			}

			return true;
		}
	private:
		jrd_file* file;
		BufferDesc* bdb;