BTree.rb in perobs-4.0.0

- old
+ new

@@ -25,11 +25,11 @@
 # OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
 # WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 
 require 'perobs/LockFile'
 require 'perobs/EquiBlobsFile'
-require 'perobs/BTreeNodeCache'
+require 'perobs/PersistentObjectCache'
 require 'perobs/BTreeNode'
 
 module PEROBS
 
   # This BTree class is very similar to a classic BTree implementation. It
@@ -38,11 +38,11 @@
   # The order of the tree specifies how many keys each node will be able to
   # hold. Leaf nodes will have a value associated with each key. Branch nodes
   # have N + 1 references to child nodes instead.
   class BTree
 
-    attr_reader :order, :nodes
+    attr_reader :order, :nodes, :node_cache
 
     # Create a new BTree object.
     # @param dir [String] Directory to store the tree file
     # @param name [String] Base name of the BTree related files in 'dir'
     # @param order [Integer] The maximum number of keys per node. This number
@@ -62,11 +62,11 @@
       @order = order
 
       # This EquiBlobsFile contains the nodes of the BTree.
       @nodes = EquiBlobsFile.new(@dir, @name,
                                  BTreeNode::node_bytes(@order))
-      @node_cache = BTreeNodeCache.new
+      @node_cache = PersistentObjectCache.new(512, BTreeNode, self)
 
       # This BTree implementation uses a write cache to improve write
       # performance of multiple successive read/write operations. This also
       # means that data may not be written on the backing store until the
       # sync() or close() methods have been called. A bug in the program or a
@@ -87,12 +87,14 @@
         PEROBS.log.fatal "Index file #{@nodes.file_name} does not exist"
       end
 
       @node_cache.clear
       @nodes.open
-      set_root(new_node(nil, @nodes.total_entries == 0 ?
-                             nil : @nodes.first_entry))
+      node = @nodes.total_entries == 0 ?
+        BTreeNode::create(self) :
+        BTreeNode::load(self, @nodes.first_entry)
+      set_root(node)
     end
 
     # Close the tree file.
     def close
       sync
@@ -102,18 +104,19 @@
 
     # Clear all pools and forget any registered spaces.
     def clear
       @node_cache.clear
       @nodes.clear
-      set_root(new_node(nil))
+      set_root(BTreeNode::create(self))
     end
 
     # Erase the backing store of the BTree. This method should only be called
     # when not having the BTree open. And it obviously and permanently erases
     # all stored data from the BTree.
     def erase
       @nodes.erase
+      @root = nil
       @dirty_flag.forced_unlock
     end
 
     # Flush all pending modifications into the tree file.
     def sync
@@ -130,11 +133,10 @@
 
     # Register a new node as root node of the tree.
     def set_root(node)
       @root = node
       @nodes.first_entry = node.node_address
-      @node_cache.set_root(node)
     end
 
     # Insert a new value into the tree using the key as a unique index. If the
     # key already exists the old value will be overwritten.
     # @param key [Integer] Unique key
@@ -176,56 +178,19 @@
     # @yield [key, value]
     def each(&block)
       @root.each(&block)
     end
 
-    # Mark the given node as being modified. This will cause the dirty_flag
-    # lock to be taken and the @is_dirty flag to be set.
-    # @param node [BTreeNode] node to mark
-    def mark_node_as_modified(node)
-      unless @is_dirty
-        @dirty_flag.lock
-        @is_dirty = true
-      end
-      @node_cache.mark_as_modified(node)
-    end
-
     # Delete the node at the given address in the BTree file.
     # @param address [Integer] address in file
     def delete_node(address)
       @node_cache.delete(address)
       @nodes.delete_blob(address)
     end
 
     # @return [String] Human reable form of the tree.
     def to_s
       @root.to_s
-    end
-
-    # Create a new BTreeNode. If the node_address is not nil, the node data is
-    # read from the backing store. The parent and is_leaf arguments are
-    # ignored in this case.
-    # @param parent [BTreeNode] parent node
-    # @param node_address [Integer or nil] address of the node to create
-    # @param is_leaf[Boolean] True if node is a leaf node, false otherweise
-    def new_node(parent, node_address = nil, is_leaf = true)
-      node = BTreeNode.new(self, parent, node_address, is_leaf)
-      @node_cache.insert(node)
-
-      node
-    end
-
-    # Return the BTreeNode that matches the given node address. If a blob
-    # address and size are given, a new node is created instead of being read
-    # from the file.
-    # @param node_address [Integer] Address of the node in the BTree file
-    # @return [BTreeNode]
-    def get_node(node_address)
-      if (node = @node_cache[node_address])
-        return node
-      end
-
-      new_node(nil, node_address)
     end
 
   end
 
 end