zache.rb in zache-0.5.0

- old
+ new

@@ -41,23 +41,33 @@
 class Zache
   # Makes a new object of the cache.
   # "sync" is whether the hash is thread-safe (`true`)
   # or not (`false`); it is recommended to leave this parameter untouched,
   # unless you really know what you are doing.
-  def initialize(sync: true)
+  #
+  # If the <tt>dirty</tt> argument is set to <tt>true</tt>, a previously
+  # calculated result will be returned if it exists.
+  def initialize(sync: true, dirty: false)
     @hash = {}
     @sync = sync
+    @dirty = dirty
     @monitor = Monitor.new
   end
 
   # Gets the value from the cache by the provided key. If the value is not
   # found in the cache, it will be calculated via the provided block. If
   # the block is not given, an exception will be raised. The lifetime
   # must be in seconds. The default lifetime is huge, which means that the
   # key will never be expired.
-  def get(key, lifetime: 2**32)
+  #
+  # If the <tt>dirty</tt> argument is set to <tt>true</tt>, a previously
+  # calculated result will be returned if it exists.
+  def get(key, lifetime: 2**32, dirty: false)
     if block_given?
+      if (dirty || @dirty) && locked? && !key_expired?(key) && @hash.key?(key)
+        return @hash[key]
+      end
       synchronized { calc(key, lifetime) { yield } }
     else
       rec = @hash[key]
       if key_expired?(key)
         @hash.delete(key)
@@ -78,10 +88,15 @@
       rec = nil
     end
     !rec.nil?
   end
 
+  # Is cache currently locked doing something?
+  def locked?
+    !@monitor.mon_try_enter { true }
+  end
+
   # Put a value into the cache.
   def put(key, value, lifetime: 2**32)
     synchronized do
       @hash[key] = {
         value: value,
@@ -122,10 +137,10 @@
     @hash[key][:value]
   end
 
   def synchronized
     if @sync
-      @monitor.synchronize { yield }
+      @monitor.mon_synchronize { yield }
     else
       yield
     end
   end
 