A persistent tree map (work in progress).

h2/src/test/org/h2/test/TestAll.java

@@ -103,6 +103,7 @@ import org.h2.test.server.TestAutoServer;
 import org.h2.test.server.TestNestedLoop;
 import org.h2.test.server.TestWeb;
 import org.h2.test.server.TestInit;
+import org.h2.test.store.TestTreeMapStore;
 import org.h2.test.synth.TestBtreeIndex;
 import org.h2.test.synth.TestCrashAPI;
 import org.h2.test.synth.TestDiskFull;
@@ -164,7 +165,6 @@ import org.h2.test.unit.TestStreams;
 import org.h2.test.unit.TestStringCache;
 import org.h2.test.unit.TestStringUtils;
 import org.h2.test.unit.TestTools;
-import org.h2.test.unit.TestTreeMapStore;
 import org.h2.test.unit.TestUtils;
 import org.h2.test.unit.TestValue;
 import org.h2.test.unit.TestValueHashMap;
@@ -661,6 +661,10 @@ kill -9 `jps -l | grep "org.h2.test." | cut -d " " -f 1`
     }
 
     private void testUnit() {
+        // store
+        new TestTreeMapStore().runTest(this);
+
+        // unit
         new TestAutoReconnect().runTest(this);
         new TestCache().runTest(this);
         new TestClearReferences().runTest(this);
@@ -703,7 +707,6 @@ kill -9 `jps -l | grep "org.h2.test." | cut -d " " -f 1`
         new TestStringCache().runTest(this);
         new TestStringUtils().runTest(this);
         new TestTools().runTest(this);
-        new TestTreeMapStore().runTest(this);
         new TestTraceSystem().runTest(this);
         new TestUpgrade().runTest(this);
         new TestUtils().runTest(this);

h2/src/test/org/h2/test/unit/TestTreeMapStore.java → h2/src/test/org/h2/test/store/TestTreeMapStore.java

@@ -3,7 +3,7 @@
  * 1.0, and under the Eclipse Public License, Version 1.0
  * (http://h2database.com/html/license.html). Initial Developer: H2 Group
  */
-package org.h2.test.unit;
+package org.h2.test.store;
 
 import java.util.Iterator;
 import java.util.Random;

h2/src/tools/org/h2/dev/store/btree/BtreeMap.java

@@ -29,23 +29,6 @@ public class BtreeMap<K, V> {
         this.valueType = valueType;
     }
 
-    /**
-     * Open a map.
-     *
-     * @param <K> the key type
-     * @param <V> the value type
-     * @param store the tree store
-     * @param name the name of the map
-     * @param keyClass the key class
-     * @param valueClass the value class
-     * @return the map
-     */
-    static <K, V> BtreeMap<K, V> open(BtreeMapStore store, String name, Class<K> keyClass, Class<V> valueClass) {
-        DataType keyType = DataTypeFactory.getDataType(keyClass);
-        DataType valueType = DataTypeFactory.getDataType(valueClass);
-        return new BtreeMap<K, V>(store, name, keyType, valueType);
-    }
-
     /**
      * Open a map.
      *

h2/src/tools/org/h2/dev/store/btree/BtreeMapStore.java

@@ -51,8 +51,6 @@ todo:
 
 - encode length in pos (1=32, 2=128, 3=512,...)
 
-- don't use any 't' blocks
-
 - floating header (avoid duplicate header)
     for each chunk, store chunk (a counter)
     for each page, store chunk id and offset to root
@@ -65,6 +63,8 @@ todo:
  */
 public class BtreeMapStore {
 
+    private static final StringType STRING_TYPE = new StringType();
+
     private final String fileName;
     private FileChannel file;
     private int pageSize = 4 * 1024;
@@ -115,11 +115,15 @@ public class BtreeMapStore {
         @SuppressWarnings("unchecked")
         BtreeMap<K, V> m = (BtreeMap<K, V>) maps.get(name);
         if (m == null) {
-            String root = meta.get("map." + name);
-            m = BtreeMap.open(this, name, keyClass, valueClass);
+            String root = meta.get("root." + name);
+            DataType keyType = getDataType(keyClass);
+            DataType valueType = getDataType(valueClass);
+            m = BtreeMap.open(this, name, keyType, valueType);
             maps.put(name, m);
-            if (root != null) {
-                root = StringUtils.arraySplit(root, ',', false)[0];
+            if (root == null) {
+                String info = m.getKeyType().asString() + "/" + m.getValueType().asString();
+                meta.put("map." + name, info);
+            } else {
                 if (!root.equals("0")) {
                     m.setRoot(Long.parseLong(root));
                 }
@@ -128,6 +132,20 @@ public class BtreeMapStore {
         return m;
     }
 
+    private DataType getDataType(Class<?> clazz) {
+        if (clazz == String.class) {
+            return STRING_TYPE;
+        }
+        return DataTypeFactory.getDataType(clazz);
+    }
+
+    private DataType getDataType(String s) {
+        if (s.equals("")) {
+            return STRING_TYPE;
+        }
+        return DataTypeFactory.fromString(s);
+    }
+
     /**
      * Mark a map as changed.
      *
@@ -141,7 +159,7 @@ public class BtreeMapStore {
     }
 
     private void open() {
-        meta = BtreeMap.open(this, "meta", String.class, String.class);
+        meta = BtreeMap.open(this, "meta", STRING_TYPE, STRING_TYPE);
         FileUtils.createDirectories(FileUtils.getParent(fileName));
         try {
             log("file open");
@@ -258,8 +276,7 @@ public class BtreeMapStore {
         // as we don't know the exact positions and entry counts
         int lenEstimate = 1 + 8;
         for (BtreeMap<?, ?> m : mapsChanged.values()) {
-            meta.put("map." + m.getName(), String.valueOf(Long.MAX_VALUE) +
-                    "," + m.getKeyType().getName() + "," + m.getValueType().getName());
+            meta.put("root." + m.getName(), String.valueOf(Long.MAX_VALUE));
             Page p = m.getRoot();
             if (p != null) {
                 lenEstimate += p.lengthIncludingTempChildren();
@@ -304,7 +321,7 @@ public class BtreeMapStore {
         for (BtreeMap<?, ?> m : mapsChanged.values()) {
             Page r = m.getRoot();
             long p = r == null ? 0 : pageId;
-            meta.put("map." + m.getName(), String.valueOf(p) + "," + m.getKeyType().getName() + "," + m.getValueType().getName());
+            meta.put("root." + m.getName(), "" + p);
             if (r != null) {
                 pageId = r.updatePageIds(pageId);
             }
@@ -488,16 +505,15 @@ public class BtreeMapStore {
         long oldMetaRootId = readMetaRootId(move.start);
         long offset = getPosition(oldMetaRootId);
         log("  meta:" + move.id + "/" + offset + " start: " + move.start);
-        BtreeMap<String, String> oldMeta = BtreeMap.open(this, "old-meta", String.class, String.class);
+        BtreeMap<String, String> oldMeta = BtreeMap.open(this, "old-meta", STRING_TYPE, STRING_TYPE);
         oldMeta.setRoot(oldMetaRootId);
         Iterator<String> it = oldMeta.keyIterator(null);
         ArrayList<Integer> oldBlocks = New.arrayList();
         while (it.hasNext()) {
             String k = it.next();
-            String v = oldMeta.get(k);
-            log("    " + k + " " + v.replace('\n', ' '));
+            String s = oldMeta.get(k);
+            log("    " + k + " " + s.replace('\n', ' '));
             if (k.startsWith("block.")) {
-                String s = oldMeta.get(k);
                 Block b = Block.fromString(s);
                 if (!blocks.containsKey(b.id)) {
                     oldBlocks.add(b.id);
@@ -512,11 +528,11 @@ public class BtreeMapStore {
             if (!maps.containsKey(k)) {
                 continue;
             }
-            String[] d = StringUtils.arraySplit(v, ',', false);
-            DataType kt = DataTypeFactory.getDataType(d[1]);
-            DataType vt = DataTypeFactory.getDataType(d[2]);
+            String[] types = StringUtils.arraySplit(s, '/', false);
+            DataType kt = getDataType(types[0]);
+            DataType vt = getDataType(types[1]);
+            long oldDataRoot = Long.parseLong(oldMeta.get("root." + k));
             BtreeMap<?, ?> oldData = BtreeMap.open(this, "old-" + k, kt, vt);
-            long oldDataRoot = Long.parseLong(d[0]);
             if (oldDataRoot == 0) {
                 // no rows
             } else {

h2/src/tools/org/h2/dev/store/btree/DataType.java

@@ -9,9 +9,9 @@ package org.h2.dev.store.btree;
 import java.nio.ByteBuffer;
 
 /**
- * A value type.
+ * A data type.
  */
-interface DataType {
+public interface DataType {
 
     /**
      * Compare two keys.
@@ -47,11 +47,11 @@ interface DataType {
     Object read(ByteBuffer buff);
 
     /**
-     * Get the tag name of the class.
+     * Get the string representation of this type.
      *
-     * @return the tag name
+     * @return the string
      */
-    String getName();
+    String asString();
 
 }
 

h2/src/tools/org/h2/dev/store/btree/DataTypeFactory.java

@@ -6,24 +6,33 @@
  */
 package org.h2.dev.store.btree;
 
+import java.io.IOException;
+import java.io.StringReader;
+
 /**
  * A factory for data types.
  */
 public class DataTypeFactory {
 
     /**
-     * Get the class with the given name.
+     * Read the data type.
      *
-     * @param name the name
-     * @return the data type
+     * @param buff the buffer
+     * @return the type
      */
-    static DataType getDataType(String name) {
-        if (name.equals("i")) {
+    static DataType fromString(String s) {
+        StringReader r = new StringReader(s);
+        char c;
+        try {
+            c = (char) r.read();
+        } catch (IOException e) {
+            throw new RuntimeException(e);
+        }
+        switch (c) {
+        case 'i':
             return new IntegerType();
-        } else if (name.equals("s")) {
-            return new StringType();
         }
-        throw new RuntimeException("Unknown data type name " + name);
+        throw new RuntimeException("Unknown data type " + c);
     }
 
     /**

h2/src/tools/org/h2/dev/store/btree/IntegerType.java

@@ -29,7 +29,7 @@ class IntegerType implements DataType {
         DataUtils.writeVarInt(buff, (Integer) x);
     }
 
-    public String getName() {
+    public String asString() {
         return "i";
     }
 

h2/src/tools/org/h2/dev/store/btree/StringType.java

@@ -47,8 +47,8 @@ class StringType implements DataType {
         }
     }
 
-    public String getName() {
-        return "s";
+    public String asString() {
+        return "";
     }
 
 }