fix: issue 716 getTypeInfo() may not return data in the order specifi…

…ed in Oracle documentation (#1506)

this replaces PR #910 as it was stale and easier to replace than fix. Original work by @zemian

pgjdbc/src/main/java/org/postgresql/jdbc/PgDatabaseMetaData.java

@@ -9,11 +9,13 @@
 import org.postgresql.core.Field;
 import org.postgresql.core.Oid;
 import org.postgresql.core.ServerVersion;
+import org.postgresql.util.ByteConverter;
 import org.postgresql.util.GT;
 import org.postgresql.util.JdbcBlackHole;
 import org.postgresql.util.PSQLException;
 import org.postgresql.util.PSQLState;
 
+import java.math.BigInteger;
 import java.sql.Array;
 import java.sql.Connection;
 import java.sql.DatabaseMetaData;
@@ -24,6 +26,9 @@
 import java.sql.Types;
 import java.util.ArrayList;
 import java.util.Arrays;
+
+import java.util.Collections;
+import java.util.Comparator;
 import java.util.HashMap;
 import java.util.Iterator;
 import java.util.List;
@@ -2247,14 +2252,18 @@ public ResultSet getTypeInfo() throws SQLException {
               connection.encodeString(Integer.toString(java.sql.DatabaseMetaData.typeSearchable));
 
     while (rs.next()) {
-      byte[][] tuple = new byte[18][];
+      byte[][] tuple = new byte[19][];
       String typname = rs.getString(1);
       int typeOid = (int) rs.getLong(2);
 
       tuple[0] = connection.encodeString(typname);
       int sqlType = connection.getTypeInfo().getSQLType(typname);
       tuple[1] =
           connection.encodeString(Integer.toString(sqlType));
+
+      /* this is just for sorting below, the result set never sees this */
+      tuple[18] = BigInteger.valueOf(sqlType).toByteArray();
+
       tuple[2] = connection
           .encodeString(Integer.toString(connection.getTypeInfo().getMaximumPrecision(typeOid)));
 
@@ -2300,6 +2309,14 @@ public ResultSet getTypeInfo() throws SQLException {
     rs.close();
     stmt.close();
 
+    Collections.sort(v, new Comparator<byte[][]>() {
+      @Override
+      public int compare(byte[][] o1, byte[][] o2) {
+        int i1 = ByteConverter.bytesToInt(o1[18]);
+        int i2 = ByteConverter.bytesToInt(o2[18]);
+        return (i1 < i2) ? -1 : ((i1 == i2) ? 0 : 1);
+      }
+    });
     return ((BaseStatement) createMetaDataStatement()).createDriverResultSet(f, v);
   }
 

pgjdbc/src/main/java/org/postgresql/util/ByteConverter.java

@@ -16,6 +16,25 @@ private ByteConverter() {
     // prevent instantiation of static helper class
   }
 
+  /**
+   * Convert a variable length array of bytes to an integer
+   * @param bytes array of bytes that can be decoded as an integer
+   * @return integer
+   */
+  public static int bytesToInt(byte []bytes) {
+    if ( bytes.length == 1 ) {
+      return (int)bytes[0];
+    }
+    if ( bytes.length == 2 ) {
+      return int2(bytes, 0);
+    }
+    if ( bytes.length == 4 ) {
+      return int4(bytes, 0);
+    } else {
+      throw new IllegalArgumentException("Argument bytes is empty");
+    }
+  }
+
   /**
    * Parses a long value from the byte array.
    *

pgjdbc/src/test/java/org/postgresql/test/jdbc4/DatabaseMetaDataTest.java

@@ -232,4 +232,17 @@ public void testGetFunctionsWithSpecificTypes() throws SQLException {
       stmt.execute("DROP FUNCTION getfunc_f3(int, varchar)");
     }
   }
+
+  @Test
+  public void testSortedDataTypes() throws SQLException {
+    // https://github.com/pgjdbc/pgjdbc/issues/716
+    DatabaseMetaData dbmd = conn.getMetaData();
+    ResultSet rs = dbmd.getTypeInfo();
+    int lastType = Integer.MIN_VALUE;
+    while (rs.next()) {
+      int type = rs.getInt("DATA_TYPE");
+      assertTrue(lastType <= type);
+      lastType = type;
+    }
+  }
 }