Add an unmunge capability to type parameters and properties

Unmunge is the reverse of munge.
While munge allows the type to return a different parameter value
or properties should than the one it was created with, unmunge
does the reverse.

It can be used for instance to store a value in a different
representation but still be able to return genuine value to the
outside world.

Signed-off-by: Brice Figureau <brice-puppet@daysofwonder.com>

4 files changed, 43 insertions, 3 deletions

diff --git a/lib/puppet/parameter.rb b/lib/puppet/parameter.rb
index 04b3aec30..ae152de56 100644
--- a/lib/puppet/parameter.rb
+++ b/lib/puppet/parameter.rb
@@ -286,6 +286,13 @@ class Puppet::Parameter
             define_method(:unsafe_munge, &block)
         end
 
+        # Does the parameter supports reverse munge?
+        # This will be called when something wants to access the parameter
+        # in a canonical form different to what the storage form is.
+        def unmunge(&block)
+            define_method(:unmunge, &block)
+        end
+
         # Mark whether we're the namevar.
         def isnamevar
             @isnamevar = true
@@ -446,6 +453,11 @@ class Puppet::Parameter
         self.class.value_collection.munge(value)
     end
 
+    # no unmunge by default
+    def unmunge(value)
+        value
+    end
+
     # A wrapper around our munging that makes sure we raise useful exceptions.
     def munge(value)
         begin
@@ -482,7 +494,9 @@ class Puppet::Parameter
         @resource = nil
     end
 
-    attr_reader :value
+    def value
+        unmunge(@value)
+    end
 
     # Store the value provided.  All of the checking should possibly be
     # late-binding (e.g., users might not exist when the value is assigned
diff --git a/lib/puppet/property.rb b/lib/puppet/property.rb
index 3bb1a4f0c..a144f28d0 100644
--- a/lib/puppet/property.rb
+++ b/lib/puppet/property.rb
@@ -332,9 +332,9 @@ class Puppet::Property < Puppet::Parameter
                     [self.class.name, @resource.name]
             end
             if match_all?
-                return @should
+                return @should.collect { |val| self.unmunge(val) }
             else
-                return @should[0]
+                return self.unmunge(@should[0])
             end
         else
             return nil
diff --git a/spec/unit/parameter.rb b/spec/unit/parameter.rb
index 94f5cfd7b..42d3103bd 100755
--- a/spec/unit/parameter.rb
+++ b/spec/unit/parameter.rb
@@ -46,6 +46,16 @@ describe Puppet::Parameter do
             @parameter.value.should == "bar"
         end
 
+        it "should unmunge the value when accessing the actual value" do
+            @parameter.class.unmunge do |value| value.to_sym end
+            @parameter.value = "foo"
+            @parameter.value.should == :foo
+        end
+
+        it "should return the actual value by default when unmunging" do
+            @parameter.unmunge("bar").should == "bar"
+        end
+
         it "should return any set value" do
             @parameter.value = "foo"
             @parameter.value.should == "foo"
diff --git a/spec/unit/property.rb b/spec/unit/property.rb
index e2ba83303..f09549ddc 100755
--- a/spec/unit/property.rb
+++ b/spec/unit/property.rb
@@ -129,6 +129,22 @@ describe Puppet::Property do
         it "should default to :first array_matching" do
             @class.array_matching.should == :first
         end
+
+        it "should unmunge the returned value if :array_matching is set to :first" do
+            @property.class.unmunge do |v| v.to_sym end
+            @class.array_matching = :first
+            @property.should = %w{one two}
+
+            @property.should.must == :one
+        end
+
+        it "should unmunge all the returned values if :array_matching is set to :all" do
+            @property.class.unmunge do |v| v.to_sym end
+            @class.array_matching = :all
+            @property.should = %w{one two}
+
+            @property.should.must == [:one, :two]
+        end
     end
 
     describe "when validating values" do