log.cs

C#数据库中间层处理,支持主流数据库,如sql、oracle等

			} 
			catch (Exception e) 
			{
				throw Trace.error(Trace.FILE_IO_ERROR, sFileProperties + " " + e);
			}
		}

		/**
		 * Method declaration
		 *
		 *
		 * @throws Exception
		 */
		private void create() 
		{
			if (Trace.TRACE) 
			{
				Trace.trace(sName);
			}

			XmlTextWriter writer = new XmlTextWriter(sFileProperties, null);
		    writer.Formatting = Formatting.Indented;
			writer.Indentation=4;
     		writer.WriteStartDocument();
			writer.WriteComment("SharpHSQL Configuration");
			writer.WriteProcessingInstruction("Instruction","Configuration Record");
			writer.WriteStartElement("Properties","");
			writer.WriteStartAttribute("LogFile","");
			writer.WriteString(sFileScript);
			writer.WriteEndAttribute();
			writer.WriteStartAttribute("DataFile","");
			writer.WriteString(sFileCache);
			writer.WriteEndAttribute();
			writer.WriteStartAttribute("Backup","");
			writer.WriteString(sFileBackup);
			writer.WriteEndAttribute();
			writer.WriteStartAttribute("Version","");
			writer.WriteString("1.0");
			writer.WriteEndAttribute();
			writer.WriteStartAttribute("ReadOnly","");
			writer.WriteString("false");
			writer.WriteEndAttribute();
			writer.WriteStartAttribute("Modified","");
			writer.WriteString("no");
			writer.WriteEndElement();
			writer.WriteEndDocument();
			writer.Flush();
			writer.Close();

			saveProperties();
		}

		/**
		 * Method declaration
		 *
		 *
		 * @return
		 *
		 * @throws Exception
		 */
		private bool isAlreadyOpen() 
		{

			// reading the last modified, wait 3 seconds, read again.
			// if the same information was read the file was not changed
			// and is probably, except the other process is blocked
			if (Trace.TRACE) 
			{
				Trace.trace();
			}

			File f = new File(sFileScript);
			DateTime l1 = f.LastWriteTime;

			try 
			{
				Thread.Sleep(3000);
			} 
			catch (Exception e) {}

			DateTime l2 = f.LastWriteTime;

			if (l1 != l2) 
			{
				return true;
			}

			// check by trying to delete the properties file
			// this will not work if some application has the file open
			// this is why the properties file is kept open when running ;-)
			// todo: check if this works in all operating systems
			closeProperties();

			if (Trace.TRACE) 
			{
				Trace.trace();
			}

			try 
			{
				(new File(sFileProperties)).Delete();
			}
			catch (Exception e)
			{
				return true;
			}

			// the file was deleted, so recreate it now
			saveProperties();

			return false;
		}

		/**
		 * Method declaration
		 *
		 *
		 * @throws Exception
		 */
		private void loadProperties() 
		{
			try 
			{
				XmlTextReader reader = new XmlTextReader(sFileProperties);
				//Read the tokens from the reader
				while ( reader.Read() )
				{
					if (XmlNodeType.Element == reader.NodeType)
					{
						sFileScript = reader.GetAttribute("LogFile");
						sFileCache = reader.GetAttribute("DataFile");
						sFileBackup = reader.GetAttribute("Backup");
						sModified = reader.GetAttribute("Modified");
		 		        sVersion = reader.GetAttribute("Version");
		 		        bReadOnly = reader.GetAttribute("ReadOnly").ToLower().Equals("true");
					}
				}
				reader.Close();
 			}
			catch (Exception e)
			{
				Console.WriteLine("Property File Exeception:", e.ToString());
			}

			if (Trace.TRACE) 
			{
				Trace.trace();
			}

		}

		/**
		 * Method declaration
		 *
		 *
		 * @throws Exception
		 */
		private void saveProperties() 
		{
			XmlTextWriter writer = new XmlTextWriter(sFileProperties, null);
		    writer.Formatting = Formatting.Indented;
			writer.Indentation=4;
     		writer.WriteStartDocument();
			writer.WriteComment("SharpHSQL Configuration");
			writer.WriteProcessingInstruction("Instruction","Configuration Record");
			writer.WriteStartElement("Properties","");
			writer.WriteStartAttribute("LogFile","");
			writer.WriteString(sFileScript);
			writer.WriteEndAttribute();
			writer.WriteStartAttribute("DataFile","");
			writer.WriteString(sFileCache);
			writer.WriteEndAttribute();
			writer.WriteStartAttribute("Backup","");
			writer.WriteString(sFileBackup);
			writer.WriteEndAttribute();
			writer.WriteStartAttribute("Version","");
			writer.WriteString(sVersion);
			writer.WriteEndAttribute();
			writer.WriteStartAttribute("ReadOnly","");
			if (bReadOnly == true)
			{
				writer.WriteString("true");
			}
			else
			{
				writer.WriteString("false");
			}
			writer.WriteEndAttribute();
			writer.WriteStartAttribute("Modified","");
			writer.WriteString(sModified);
			writer.WriteEndElement();
			writer.WriteEndDocument();
			writer.Flush();
			writer.Close();

			closeProperties();

			if (Trace.TRACE) 
			{
				Trace.trace();
			}
		}

		/**
		 * Method declaration
		 *
		 *
		 * @throws Exception
		 */
		private void backup() 
		{
			if (Trace.TRACE) 
			{
				Trace.trace();

				// if there is no cache file then backup is not necessary
			}

			if (!(new File(sFileCache)).Exists) 
			{
				return;
			}

			try 
			{
				DateTime time = DateTime.Now;

				// create a '.new' file; rename later
				BinaryWriter f = new BinaryWriter(new FileStream(sFileBackup + ".new",FileMode.OpenOrCreate,FileAccess.Write));
				byte[]		 b = new byte[COPY_BLOCK_SIZE];
				BinaryReader fin = new BinaryReader(new FileStream(sFileCache,FileMode.Open,FileAccess.Read));

				while (true) 
				{
					int l = fin.Read(b, 0, COPY_BLOCK_SIZE);

					if (l == 0) 
					{
						break;
					}

					f.Write(b, 0, l);
				}

				f.Close();
				fin.Close();

				TimeSpan execution = DateTime.Now.Subtract(time);

				if (Trace.TRACE) 
				{
					Trace.trace(execution.TotalMilliseconds.ToInt64());
				}
			}
			catch (Exception e) 
			{
				throw Trace.error(Trace.FILE_IO_ERROR, sFileBackup);
			}
		}

		/**
		 * Method declaration
		 *
		 *
		 * @throws Exception
		 */
		private void restoreBackup() 
		{
			if (Trace.TRACE) 
			{
				Trace.trace("not closed last time!");
			}

			if (!(new File(sFileBackup)).Exists) 
			{

				// the backup don't exists because it was never made or is empty
				// the cache file must be deleted in this case
				(new File(sFileCache)).Delete();

				return;
			}

			try 
			{
				DateTime		time = DateTime.Now;
				BinaryReader f = new BinaryReader(new FileStream(sFileBackup,FileMode.Open,FileAccess.Read));
				BinaryWriter cache = new BinaryWriter(new FileStream(sFileCache,FileMode.OpenOrCreate,FileAccess.Write));
				byte[]		b = new byte[COPY_BLOCK_SIZE];

				while (true) 
				{
					int l = f.Read(b, 0, COPY_BLOCK_SIZE);

					if (l == 0) 
					{
						break;
					}

					cache.Write(b, 0, l);
				}

				cache.Close();
				f.Close();

				TimeSpan execution = DateTime.Now.Subtract(time);

				if (Trace.TRACE) 
				{
					Trace.trace(execution.TotalMilliseconds.ToInt64());
				}
			} 
			catch (Exception e) 
			{
				throw Trace.error(Trace.FILE_IO_ERROR, sFileBackup);
			}
		}

		/**
		 * Method declaration
		 *
		 *
		 * @throws Exception
		 */
		private void openScript() 
		{
			if (Trace.TRACE) 
			{
				Trace.trace();
			}

			try 
			{
				// todo: use a compressed stream
				wScript = new StreamWriter(sFileScript,true);
			} 
			catch (Exception e) 
			{
				Trace.error(Trace.FILE_IO_ERROR, sFileScript);
			}
		}

		/**
		 * Method declaration
		 *
		 *
		 * @throws Exception
		 */
		private void closeScript() 
		{
			if (Trace.TRACE) 
			{
				Trace.trace();
			}

			try 
			{
				if (wScript != null) 
				{
					wScript.Close();

					wScript = null;
				}
			} 
			catch (Exception e) 
			{
				Trace.error(Trace.FILE_IO_ERROR, sFileScript);
			}
		}

		/**
		 * Method declaration
		 *
		 *
		 * @throws Exception
		 */
		private void runScript() 
		{
			if (Trace.TRACE) 
			{
				Trace.trace();
			}

			if (!(new File(sFileScript)).Exists) 
			{
				return;
			}

			bRestoring = true;

			dDatabase.setReferentialIntegrity(false);

			ArrayList channel = new ArrayList();

			channel.Add(cSystem);

			Channel current = cSystem;
			int     size = 1;

			try 
			{
				DateTime	     time = DateTime.Now;
				StreamReader r = new StreamReader(sFileScript);

				while (true) 
				{
					string s = r.ReadLine();

					if (s == null) 
					{
						break;
					}

					if (s.StartsWith("/*C")) 
					{
						int id = Int32.FromString(s.Substring(3,(s.IndexOf('*', 4)-3)));

						if (id > channel.Count)
						{
							current = new Channel(cSystem, id);

							channel.Insert(id, current);
							dDatabase.registerChannel(current);
						}
						else 
						{
							current = (Channel) channel[id - 1];
						}

						s = s.Substring(s.IndexOf('/', 1) + 1);
					}

					if (!s.Equals("")) 
					{
						dDatabase.execute(s, current);
					}

					if (s.Equals("DISCONNECT")) 
					{
						int id = current.getId();

						current = new Channel(cSystem, id);

						channel.RemoveAt(id);
						channel.Insert(id, current);
					}
				}

				r.Close();

				for (int i = 0; i < size; i++) 
				{
					current = (Channel) channel[i];

					if (current != null) 
					{
						current.rollback();
					}
				}

				TimeSpan execution = DateTime.Now.Subtract(time);

				if (Trace.TRACE) 
				{
					Trace.trace(execution.TotalMilliseconds.ToInt64());
				}
			} 
			catch (IOException e) 
			{
				throw Trace.error(Trace.FILE_IO_ERROR, sFileScript + " " + e);
			}

			dDatabase.setReferentialIntegrity(true);

			bRestoring = false;
		}

		/**
		 * Method declaration
		 *
		 *
		 * @param full
		 *
		 * @throws Exception
		 */
		private void writeScript(bool full) 
		{
			if (Trace.TRACE) 
			{
				Trace.trace();

				// create script in '.new' file
			}

			(new File(sFileScript + ".new")).Delete();

			// script; but only positions of cached tables, not full
			scriptToFile(dDatabase, sFileScript + ".new", full, cSystem);
		}

		/**
		 * Method declaration
		 *
		 *
		 * @param w
		 * @param s
		 *
		 * @throws IOException
		 */
		private static void writeLine(StreamWriter w, string s) 
		{
			w.WriteLine(s);
		}

		/**
		 * Method declaration
		 *
		 *
		 * @param r
		 *
		 * @return
		 *
		 * @throws IOException
		 */
		private static string readLine(TextReader r) 
		{
			string s = r.ReadLine();

			return stringConverter.asciiToUnicode(s);
		}

	}
}