Refactored page store to support other page stores

Author: justinsb

cloudata-server-shared/src/main/java/com/cloudata/btree/BranchPage.java

@@ -21,8 +21,8 @@ public class BranchPage extends Page {
 
     Mutable mutable;
 
-    public BranchPage(Page parent, int pageNumber, ByteBuffer buffer) {
-        super(parent, pageNumber, buffer);
+    public BranchPage(Btree btree, Page parent, int pageNumber, ByteBuffer buffer) {
+        super(btree, parent, pageNumber, buffer);
     }
 
     static class Mutable {
@@ -144,7 +144,7 @@ public boolean walk(Transaction txn, ByteBuffer from, EntryListener listener) {
 
                 int pageNumber = entry.pageNumber;
 
-                Page childPage = txn.getPage(page, pageNumber);
+                Page childPage = txn.getPage(page.btree, page, pageNumber);
 
                 boolean keepGoing = childPage.walk(txn, from, listener);
                 if (!keepGoing) {
@@ -166,7 +166,7 @@ public void updateLbound(Transaction txn, int pageNumber) {
                 }
 
                 ByteBuffer oldKey = entry.key;
-                Page childPage = txn.getPage(page, pageNumber);
+                Page childPage = txn.getPage(page.btree, page, pageNumber);
 
                 ByteBuffer newKey = childPage.getKeyLbound();
                 entries.set(i, new Entry(newKey, pageNumber));
@@ -363,7 +363,7 @@ public boolean walk(Transaction txn, ByteBuffer from, EntryListener listener) {
         while (pos < n) {
             int pageNumber = getPageNumber(pos);
 
-            Page page = txn.getPage(this, pageNumber);
+            Page page = txn.getPage(btree, this, pageNumber);
             boolean keepGoing = page.walk(txn, from, listener);
             if (!keepGoing) {
                 return false;
@@ -421,7 +421,7 @@ public <V> void doAction(Transaction txn, ByteBuffer key, RowOperation<V> operat
 
         int pageNumber = getPageNumber(pos);
 
-        Page childPage = txn.getPage(this, pageNumber);
+        Page childPage = txn.getPage(btree, this, pageNumber);
 
         ByteBuffer oldLbound = childPage.getKeyLbound();
 
@@ -491,12 +491,12 @@ public void dump(PrintStream os) {
         }
     }
 
-    public static BranchPage createNew(Page parent, int pageNumber, Page childPage) {
+    public static BranchPage createNew(Btree btree, Page parent, int pageNumber, Page childPage) {
         ByteBuffer empty = ByteBuffer.allocate(6);
         empty.putShort((short) 0);
         empty.flip();
 
-        BranchPage page = new BranchPage(parent, pageNumber, empty);
+        BranchPage page = new BranchPage(btree, parent, pageNumber, empty);
         page.getMutable().setChildren(childPage);
 
         return page;

cloudata-server-shared/src/main/java/com/cloudata/btree/Btree.java

@@ -9,24 +9,24 @@
 public class Btree {
     private static final Logger log = LoggerFactory.getLogger(Btree.class);
 
-    final PageStore pageStore;
+    final Database db;
     final boolean uniqueKeys;
 
     final Lock writeLock = new ReentrantLock();
 
-    public Btree(PageStore pageStore, boolean uniqueKeys) {
-        this.pageStore = pageStore;
+    public Btree(Database db, boolean uniqueKeys) {
+        this.db = db;
         this.uniqueKeys = uniqueKeys;
     }
 
     public WriteTransaction beginReadWrite() {
         writeLock.lock();
-        WriteTransaction txn = pageStore.beginReadWriteTransaction(writeLock);
+        WriteTransaction txn = db.transactionTracker.beginReadWriteTransaction(writeLock);
         return txn;
     }
 
     public ReadOnlyTransaction beginReadOnly() {
-        ReadOnlyTransaction txn = pageStore.beginReadOnlyTransaction();
+        ReadOnlyTransaction txn = db.transactionTracker.beginReadOnlyTransaction();
         return txn;
     }
 

cloudata-server-shared/src/main/java/com/cloudata/btree/Database.java

@@ -0,0 +1,14 @@
+package com.cloudata.btree;
+
+public class Database {
+    final PageStore pageStore;
+    final TransactionTracker transactionTracker;
+
+    Database(PageStore pageStore) {
+        this.pageStore = pageStore;
+
+        MasterPage latest = pageStore.findLatestMasterPage();
+        this.transactionTracker = new TransactionTracker(this, latest);
+    }
+
+}

cloudata-server-shared/src/main/java/com/cloudata/btree/LeafPage.java

@@ -44,9 +44,9 @@ public class LeafPage extends Page {
 
     final boolean uniqueKeys;
 
-    public LeafPage(Page parent, int pageNumber, ByteBuffer buffer, boolean uniqueKeys) {
-        super(parent, pageNumber, buffer);
-        this.uniqueKeys = uniqueKeys;
+    public LeafPage(Btree btree, Page parent, int pageNumber, ByteBuffer buffer) {
+        super(btree, parent, pageNumber, buffer);
+        this.uniqueKeys = btree.isUniqueKeys();
     }
 
     static class Mutable {
@@ -57,6 +57,8 @@ static class Mutable {
         int totalKeySize;
         int totalValueSize;
 
+        final Btree btree;
+
         int firstGTE(ByteBuffer find) {
             int n = getEntryCount();
             int pos;
@@ -146,6 +148,7 @@ <V> void doAction(ByteBuffer key, RowOperation<V> operation) {
         }
 
         Mutable(LeafPage page) {
+            this.btree = page.btree;
             this.uniqueKeys = page.uniqueKeys;
             int n = page.getEntryCount();
 
@@ -189,7 +192,7 @@ List<Page> split(WriteTransaction transaction, LeafPage original) {
                         target = original;
                     } else {
                         int pageNumber = transaction.assignPageNumber();
-                        target = LeafPage.createNew(original.parent, pageNumber, uniqueKeys);
+                        target = LeafPage.createNew(btree, original.parent, pageNumber);
                         extraPages.add(target);
                     }
 
@@ -517,7 +520,7 @@ public byte getPageType() {
         return PAGE_TYPE;
     }
 
-    public static LeafPage createNew(Page parent, int pageNumber, boolean uniqueKeys) {
+    public static LeafPage createNew(Btree btree, Page parent, int pageNumber) {
         // TODO: Reuse a shared buffer?
         ByteBuffer empty = ByteBuffer.allocate(6);
         empty.putShort((short) 0);
@@ -526,7 +529,7 @@ public static LeafPage createNew(Page parent, int pageNumber, boolean uniqueKeys
 
         empty.flip();
 
-        return new LeafPage(parent, pageNumber, empty, uniqueKeys);
+        return new LeafPage(btree, parent, pageNumber, empty);
     }
 
     @Override