move Migration support into OpenSim.Data, because it

really turned out to be small enough to not need it's own
assembly

OpenSim/Data/Migration.cs

@@ -0,0 +1,198 @@
+/*
+ * Copyright (c) Contributors, http://opensimulator.org/
+ * See CONTRIBUTORS.TXT for a full list of copyright holders.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *     * Redistributions of source code must retain the above copyright
+ *       notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above copyright
+ *       notice, this list of conditions and the following disclaimer in the
+ *       documentation and/or other materials provided with the distribution.
+ *     * Neither the name of the OpenSim Project nor the
+ *       names of its contributors may be used to endorse or promote products
+ *       derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE DEVELOPERS ``AS IS'' AND ANY
+ * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+ * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE CONTRIBUTORS BE LIABLE FOR ANY
+ * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+using System;
+using System.Collections.Generic;
+using System.Data;
+using System.Data.Common;
+using System.IO;
+using System.Reflection;
+using System.Text.RegularExpressions;
+using log4net;
+
+namespace OpenSim.Data
+{
+    /// <summary> 
+    ///
+    /// The Migration theory is based on the ruby on rails concept.
+    /// Each database driver is going to be allowed to have files in
+    /// Resources that specify the database migrations.  They will be
+    /// of the form:
+    ///
+    ///    001_Users.sql
+    ///    002_Users.sql
+    ///    003_Users.sql
+    ///    001_Prims.sql
+    ///    002_Prims.sql
+    ///    ...etc...
+    ///
+    /// When a database driver starts up, it specifies a resource that
+    /// needs to be brought up to the current revision.  For instance:
+    ///
+    ///    Migration um = new Migration(DbConnection, "Users");
+    ///    um.Upgrade();
+    ///
+    /// This works out which version Users is at, and applies all the
+    /// revisions past it to it.  If there is no users table, all
+    /// revisions are applied in order.  Consider each future
+    /// migration to be an incremental roll forward of the tables in
+    /// question.
+    ///
+    /// </summary>
+
+    public class Migration
+    {
+        private static readonly log4net.ILog m_log = log4net.LogManager.GetLogger(System.Reflection.MethodBase.GetCurrentMethod().DeclaringType);
+
+        private string _type;
+        private DbConnection _conn;
+        private string _subtype;
+        private Assembly _assem;
+        
+        private static readonly string _migrations_create = "create table migrations(name varchar(100), version int)";
+        private static readonly string _migrations_init = "insert into migrations values('migrations', 1)";
+        private static readonly string _migrations_find = "select version from migrations where name='migrations'";
+        
+        public Migration(DbConnection conn, Assembly assem, string type)
+        {
+            _type = type;
+            _conn = conn;
+            _assem = assem;
+        }
+
+        private void Initialize()
+        {
+            // clever, eh, we figure out which migrations version we are
+            int migration_version = FindVersion("migrations");
+
+            if (migration_version > 0) 
+                return;
+
+            // If not, create the migration tables
+            DbCommand cmd = _conn.CreateCommand();
+            cmd.CommandText = _migrations_create;
+            cmd.ExecuteNonQuery();
+
+            UpdateVersion("migrations", 1);
+        }
+
+        public void Update()
+        {
+            int version = 0;
+            version = FindVersion(_type);
+
+            List<string> migrations = GetMigrationsAfter(version);
+            DbCommand cmd = _conn.CreateCommand();
+            foreach (string m in migrations) 
+            {
+                cmd.CommandText = m;
+                cmd.ExecuteNonQuery();
+            }
+            UpdateVersion(_type, MaxVersion());
+        }
+
+        private int MaxVersion()
+        {
+            int max = 0;
+            
+            string[] names = _assem.GetManifestResourceNames();
+            List<string> migrations = new List<string>();
+            Regex r = new Regex(@"^(\d\d\d)_" + _type + @"\.sql");
+
+            foreach (string s in names)
+            {
+                Match m = r.Match(s);
+                int MigrationVersion = int.Parse(m.Groups[1].ToString());
+                if ( MigrationVersion > max )
+                    max = MigrationVersion;
+            }
+            return max;
+        }
+
+        private int FindVersion(string type) 
+        {
+            int version = 0;
+            DbCommand cmd = _conn.CreateCommand();
+            cmd.CommandText = "select version from migrations where name='" + type + "' limit 1";
+            using (IDataReader reader = cmd.ExecuteReader())
+            {
+                if (reader.Read())
+                {
+                    version = Convert.ToInt32(reader["version"]);
+                }
+                reader.Close();
+            }
+            return version;
+        }
+        
+        private void UpdateVersion(string type, int version) 
+        {
+            DbCommand cmd = _conn.CreateCommand();
+            cmd.CommandText = "update migrations set version=" + version + " where name='" + type + "'";
+            cmd.ExecuteNonQuery();
+        }
+        
+        private List<string> GetAllMigrations()
+        {
+            return GetMigrationsAfter(0);
+        }
+
+        private List<string> GetMigrationsAfter(int version)
+        {
+            string[] names = _assem.GetManifestResourceNames();
+            List<string> migrations = new List<string>();
+
+            Regex r = new Regex(@"^(\d\d\d)_" + _type + @"\.sql");
+
+            foreach (string s in names)
+            {
+                m_log.Info("MIGRATION: Resources: " + s);
+                if (s.EndsWith(_type + @"\.sql"))
+                {
+                    Match m = r.Match(s);
+                    m_log.Info("MIGRATION: Match: " + m.Groups[1].ToString());
+                    int MigrationVersion = int.Parse(m.Groups[1].ToString());
+                    using (Stream resource = _assem.GetManifestResourceStream(s))
+                    {
+                        using (StreamReader resourceReader = new StreamReader(resource))
+                        {
+                            string resourceString = resourceReader.ReadToEnd();
+                            migrations.Add(resourceString);
+                        }
+                    }
+                }
+            }
+
+            // TODO: once this is working, get rid of this
+            if (migrations.Count < 1) {
+                throw new Exception(string.Format("Resource '{0}' was not found", _type));
+            }
+
+            return migrations;
+        }
+    }
+}