src/org/cacert/gigi/database/DatabaseConnection.java

   1 package org.cacert.gigi.database;
   2
   3 import java.io.IOException;
   4 import java.io.InputStream;
   5 import java.io.PrintWriter;
   6 import java.sql.Connection;
   7 import java.sql.DriverManager;
   8 import java.sql.PreparedStatement;
   9 import java.sql.ResultSet;
  10 import java.sql.SQLException;
  11 import java.sql.Statement;
  12 import java.util.HashMap;
  13 import java.util.HashSet;
  14 import java.util.Map.Entry;
  15 import java.util.Properties;
  16 import java.util.StringJoiner;
  17 import java.util.concurrent.LinkedBlockingDeque;
  18 import java.util.regex.Matcher;
  19 import java.util.regex.Pattern;
  20
  21 import org.cacert.gigi.database.SQLFileManager.ImportType;
  22
  23 public class DatabaseConnection {
  24
  25     public static class Link implements AutoCloseable {
  26
  27         private DatabaseConnection target;
  28
  29         protected Link(DatabaseConnection target) {
  30             this.target = target;
  31         }
  32
  33         @Override
  34         public void close() {
  35             synchronized (DatabaseConnection.class) {
  36                 Link i = instances.get(Thread.currentThread());
  37                 if (i != this) {
  38                     throw new Error();
  39                 }
  40                 instances.remove(Thread.currentThread());
  41                 pool.add(target);
  42             }
  43         }
  44
  45     }
  46
  47     public static final int MAX_CACHED_INSTANCES = 3;
  48
  49     private static class StatementDescriptor {
  50
  51         String query;
  52
  53         boolean scrollable;
  54
  55         int instance;
  56
  57         PreparedStatement target;
  58
  59         public StatementDescriptor(String query, boolean scrollable) {
  60             this.query = query;
  61             this.scrollable = scrollable;
  62             this.instance = 0;
  63         }
  64
  65         public synchronized void instanciate(Connection c) throws SQLException {
  66             if (scrollable) {
  67                 target = c.prepareStatement(query, ResultSet.TYPE_SCROLL_INSENSITIVE, ResultSet.CONCUR_READ_ONLY);
  68             } else {
  69                 target = c.prepareStatement(query, query.startsWith("SELECT ") ? Statement.NO_GENERATED_KEYS : Statement.RETURN_GENERATED_KEYS);
  70             }
  71
  72         }
  73
  74         public synchronized PreparedStatement getTarget() {
  75             return target;
  76         }
  77
  78         public synchronized void increase() {
  79             if (target != null) {
  80                 throw new IllegalStateException();
  81             }
  82             instance++;
  83         }
  84
  85         @Override
  86         public int hashCode() {
  87             final int prime = 31;
  88             int result = 1;
  89             result = prime * result + instance;
  90             result = prime * result + ((query == null) ? 0 : query.hashCode());
  91             result = prime * result + (scrollable ? 1231 : 1237);
  92             return result;
  93         }
  94
  95         @Override
  96         public boolean equals(Object obj) {
  97             if (this == obj) {
  98                 return true;
  99             }
 100             if (obj == null) {
 101                 return false;
 102             }
 103             if (getClass() != obj.getClass()) {
 104                 return false;
 105             }
 106             StatementDescriptor other = (StatementDescriptor) obj;
 107             if (instance != other.instance) {
 108                 return false;
 109             }
 110             if (query == null) {
 111                 if (other.query != null) {
 112                     return false;
 113                 }
 114             } else if ( !query.equals(other.query)) {
 115                 return false;
 116             }
 117             if (scrollable != other.scrollable) {
 118                 return false;
 119             }
 120             return true;
 121         }
 122
 123     }
 124
 125     public static final int CURRENT_SCHEMA_VERSION = 16;
 126
 127     public static final int CONNECTION_TIMEOUT = 24 * 60 * 60;
 128
 129     private Connection c;
 130
 131     private HashMap<StatementDescriptor, PreparedStatement> statements = new HashMap<StatementDescriptor, PreparedStatement>();
 132
 133     private HashSet<PreparedStatement> underUse = new HashSet<>();
 134
 135     private static Properties credentials;
 136
 137     private Statement adHoc;
 138
 139     public DatabaseConnection() {
 140         try {
 141             Class.forName(credentials.getProperty("sql.driver"));
 142         } catch (ClassNotFoundException e) {
 143             e.printStackTrace();
 144         }
 145         tryConnect();
 146
 147     }
 148
 149     private void tryConnect() {
 150         try {
 151             c = DriverManager.getConnection(credentials.getProperty("sql.url") + "?socketTimeout=" + CONNECTION_TIMEOUT, credentials.getProperty("sql.user"), credentials.getProperty("sql.password"));
 152             adHoc = c.createStatement();
 153         } catch (SQLException e) {
 154             e.printStackTrace();
 155         }
 156     }
 157
 158     protected synchronized PreparedStatement prepareInternal(String query) throws SQLException {
 159         return prepareInternal(query, false);
 160     }
 161
 162     protected synchronized PreparedStatement prepareInternal(String query, boolean scrollable) throws SQLException {
 163
 164         ensureOpen();
 165         query = preprocessQuery(query);
 166         StatementDescriptor searchHead = new StatementDescriptor(query, scrollable);
 167         PreparedStatement statement = null;
 168         while (statement == null) {
 169             statement = statements.get(searchHead);
 170             if (statement == null) {
 171                 searchHead.instanciate(c);
 172                 statement = searchHead.getTarget();
 173                 if (searchHead.instance >= MAX_CACHED_INSTANCES) {
 174                     return statement;
 175                 }
 176                 underUse.add(statement);
 177                 statements.put(searchHead, statement);
 178             } else if (underUse.contains(statement)) {
 179                 searchHead.increase();
 180                 statement = null;
 181             } else {
 182                 underUse.add(statement);
 183             }
 184         }
 185         return statement;
 186     }
 187
 188     protected synchronized PreparedStatement prepareInternalScrollable(String query) throws SQLException {
 189         return prepareInternal(query, true);
 190     }
 191
 192     private long lastAction = System.currentTimeMillis();
 193
 194     private void ensureOpen() {
 195         if (System.currentTimeMillis() - lastAction > CONNECTION_TIMEOUT * 1000L) {
 196             try {
 197                 ResultSet rs = adHoc.executeQuery("SELECT 1");
 198                 rs.close();
 199                 lastAction = System.currentTimeMillis();
 200                 return;
 201             } catch (SQLException e) {
 202             }
 203             statements.clear();
 204             tryConnect();
 205         }
 206         lastAction = System.currentTimeMillis();
 207     }
 208
 209     private static HashMap<Thread, Link> instances = new HashMap<>();
 210
 211     private static LinkedBlockingDeque<DatabaseConnection> pool = new LinkedBlockingDeque<>();
 212
 213     private static int connCount = 0;
 214
 215     public static synchronized DatabaseConnection getInstance() {
 216         Link l = instances.get(Thread.currentThread());
 217         if (l == null) {
 218             throw new Error("No database connection allocated");
 219         }
 220         return l.target;
 221     }
 222
 223     public static synchronized boolean hasInstance() {
 224         Link l = instances.get(Thread.currentThread());
 225         return l != null;
 226     }
 227
 228     public static boolean isInited() {
 229         return credentials != null;
 230     }
 231
 232     public static void init(Properties conf) {
 233         if (credentials != null) {
 234             throw new Error("Re-initiaizing is forbidden.");
 235         }
 236         credentials = conf;
 237         try (Link i = newLink(false)) {
 238             int version = 0;
 239             try (GigiPreparedStatement gigiPreparedStatement = new GigiPreparedStatement("SELECT version FROM \"schemeVersion\" ORDER BY version DESC LIMIT 1;")) {
 240                 GigiResultSet rs = gigiPreparedStatement.executeQuery();
 241                 if (rs.next()) {
 242                     version = rs.getInt(1);
 243                 }
 244             }
 245             if (version == CURRENT_SCHEMA_VERSION) {
 246                 return; // Good to go
 247             }
 248             if (version > CURRENT_SCHEMA_VERSION) {
 249                 throw new Error("Invalid database version. Please fix this.");
 250             }
 251             upgrade(version);
 252         } catch (InterruptedException e) {
 253             throw new Error(e);
 254         }
 255     }
 256
 257     private static void upgrade(int version) {
 258         try {
 259             Statement s = getInstance().c.createStatement();
 260             try {
 261                 while (version < CURRENT_SCHEMA_VERSION) {
 262                     addUpgradeScript(Integer.toString(version), s);
 263                     version++;
 264                 }
 265                 s.addBatch("UPDATE \"schemeVersion\" SET version='" + version + "'");
 266                 System.out.println("UPGRADING Database to version " + version);
 267                 s.executeBatch();
 268                 System.out.println("done.");
 269             } finally {
 270                 s.close();
 271             }
 272         } catch (SQLException e) {
 273             e.printStackTrace();
 274         } catch (IOException e) {
 275             e.printStackTrace();
 276         }
 277     }
 278
 279     private static void addUpgradeScript(String version, Statement s) throws Error, IOException, SQLException {
 280         try (InputStream resourceAsStream = DatabaseConnection.class.getResourceAsStream("upgrade/from_" + version + ".sql")) {
 281             if (resourceAsStream == null) {
 282                 throw new Error("Upgrade script from version " + version + " was not found.");
 283             }
 284             SQLFileManager.addFile(s, resourceAsStream, ImportType.PRODUCTION);
 285         }
 286     }
 287
 288     public static final String preprocessQuery(String originalQuery) {
 289         originalQuery = originalQuery.replace('`', '"');
 290         if (originalQuery.matches("^INSERT INTO [^ ]+ SET .*")) {
 291             Pattern p = Pattern.compile("INSERT INTO ([^ ]+) SET (.*)");
 292             Matcher m = p.matcher(originalQuery);
 293             if (m.matches()) {
 294                 String replacement = "INSERT INTO " + toIdentifier(m.group(1));
 295                 String[] parts = m.group(2).split(",");
 296                 StringJoiner columns = new StringJoiner(", ");
 297                 StringJoiner values = new StringJoiner(", ");
 298                 for (int i = 0; i < parts.length; i++) {
 299                     String[] split = parts[i].split("=", 2);
 300                     columns.add(toIdentifier(split[0]));
 301                     values.add(split[1]);
 302                 }
 303                 replacement += "(" + columns.toString() + ") VALUES(" + values.toString() + ")";
 304                 return replacement;
 305             }
 306         }
 307
 308         //
 309         return originalQuery;
 310     }
 311
 312     private static CharSequence toIdentifier(String ident) {
 313         ident = ident.trim();
 314         if ( !ident.startsWith("\"")) {
 315             ident = "\"" + ident;
 316         }
 317         if ( !ident.endsWith("\"")) {
 318             ident = ident + "\"";
 319         }
 320         return ident;
 321     }
 322
 323     protected synchronized void returnStatement(PreparedStatement target) throws SQLException {
 324         if ( !underUse.remove(target)) {
 325             target.close();
 326         }
 327     }
 328
 329     public synchronized int getNumberOfLockedStatements() {
 330         return underUse.size();
 331     }
 332
 333     public synchronized void lockedStatements(PrintWriter writer) {
 334         writer.println(underUse.size());
 335         for (PreparedStatement ps : underUse) {
 336             for (Entry<StatementDescriptor, PreparedStatement> e : statements.entrySet()) {
 337                 if (e.getValue() == ps) {
 338                     writer.println("<br/>");
 339                     writer.println(e.getKey().instance + ":");
 340
 341                     writer.println(e.getKey().query);
 342                 }
 343             }
 344         }
 345     }
 346
 347     public static synchronized Link newLink(boolean readOnly) throws InterruptedException {
 348         if (instances.get(Thread.currentThread()) != null) {
 349             throw new Error("There is already a connection allocated for this thread.");
 350         }
 351         if (pool.isEmpty() && connCount < 5) {
 352             pool.addLast(new DatabaseConnection());
 353             connCount++;
 354         }
 355         DatabaseConnection conn = pool.takeFirst();
 356         try {
 357             conn.c.setReadOnly(readOnly);
 358         } catch (SQLException e) {
 359             throw new Error(e);
 360         }
 361         Link l = new Link(conn);
 362         instances.put(Thread.currentThread(), l);
 363         return l;
 364     }
 365 }