Gibbler - v0.7 ALPHAGit-like hashes and history for Ruby objects for Ruby 1.8, 1.9 and JRuby.

Check out the screencast created by Alex Peuchert.

Important Information Regarding Your DigestsDigest calculation changed in the 0.7 release for Proc objects. See "News" below for more info.

Example 1 -- Basic Usage require 'gibbler'

"kimmy".gibbler              # => c8027100ecc54945ab15ddac529230e38b1ba6a1
    :kimmy.gibbler               # => 52be7494a602d85ff5d8a8ab4ffe7f1b171587df

config = {}
    config.gibbler               # => 4fdcadc66a38feb9c57faf3c5a18d5e76a6d29bf
    config.gibbled?              # => false

config[:server] = {          
      :users => [:dave, :ali],   
      :ports => [22, 80, 443]    
    }                            
    config.gibbled?              # => true
    config.gibbler               # => ef23d605f8c4fc80a8e580f9a0e8dab8426454a8

config[:server][:users] << :yanni

config.gibbler               # => 4c558a56bc2abf5f8a845a69e47ceb5e0003683f

config.gibbler.short         # => 4c558a56Example 2 -- Object History     Gibbler can also keep track of the history of changes to an object. By default Gibbler supports history for Hash, Array, and String objects. The gibbler_commit method creates a clone of the current object and stores in an instance variable using the current hash digest as the key.

require 'gibbler'
    require 'gibbler/history'

a = { :magic => :original }     
    a.gibbler_commit             # => d7049916ddb25e6cc438b1028fb957e5139f9910

a[:magic] = :updated           
    a.gibbler_commit             # => b668098e16d08898532bf3aa33ce2253a3a4150e

a[:magic] = :changed 
    a.gibbler_commit             # => 0b11c377fccd44554a601e5d2b135c46dc1c4cb1

a.gibbler_history            # => d7049916, b668098e, 0b11c377

a.gibbler_revert! 'd7049916' # Return to a specific commit
    a.gibbler                    # => d7049916ddb25e6cc438b1028fb957e5139f9910
    a                            # => { :magic => :original }

a.delete :magic

a.gibbler_revert!            # Return to the previous commit  
    a.gibbler                    # => 0b11c377fccd44554a601e5d2b135c46dc1c4cb1
    a                            # => { :magic => :changed }

a.gibbler_object 'b668098e'  # => { :magic => :updated }
    a.gibbler_stamp              # => 2009-07-01 18:56:52 -0400

Example 3 -- Method AliasesIf you have control over the namespaces of your objects, you can use the method aliases to tighten up your code a bit. The "gibbler" and "gibbled?" methods can be accessed via "digest" and "changed?", respectively. (The reason they're not enabled by default is to avoid conflicts.)

require 'gibbler/aliases'

"kimmy".digest               # => c8027100ecc54945ab15ddac529230e38b1ba6a1
    :kimmy.digest                # => 52be7494a602d85ff5d8a8ab4ffe7f1b171587df

a = [:a, :b, :c]
    a.digest                     # => e554061823b8f06367555d1ee4c25b4ffee61944
    a << :d
    a.changed?                   # => trueThe history methods also have aliases which remove the "gibbler".

require 'gibbler/aliases'
    require 'gibbler/history'

a = { :magic => :original }
a.commit
a.history
a.revert!

1. etc...Supported ClassesGibbler methods are available only to the classes which explicitly include them (see RDocshttp://delano.github.com/gibbler for details on which classes are supported by default). You can also extend custom objects:

class FullHouse
      include Gibbler::Complex
      attr_accessor :roles
    end

a = FullHouse.new
    a.gibbler                    # => 4192d4cb59975813f117a51dcd4454ac16df6703

a.roles = [:jesse, :joey, :danny, :kimmy, :michelle, :dj, :stephanie]
    a.gibbler                    # => 6ea546919dc4caa2bab69799b71d48810a1b48faGibbler::Complex creates a digest based on the name of the class and the names and values of the instance variables. See the RDocshttp://delano.github.com/gibbler for other Gibbler:: types.

If you want to support all Ruby objects, add the following to your application:

class Object
      include Gibbler::String
    endGibbler::String creates a digest based on the name of the class and the output of the to_s method. This is a reasonable default for most objects however any object that includes the object address in to_s (e.g. "Object:0x0x4ac9f0...") will produce unreliable digests (because the address can change).

As of 0.7 all Proc objects have the same digest: 12075835e94be34438376cd7a54c8db7e746f15d.

ALPHA NoticeThis code is fresh so the interface may change. Some things to keep in mind:

Gibbler history is not suitable for very large objects since it keeps complete copies of the object in memory. This is a very early implementation of this feature so don't rely on it for production code. Digest calculation may change between minor releases (e.g. 0.6 to 0.7, etc) Don't forget to enjoy what you do! News2009-10-07: Digest calculation for Proc objects has changed.Proc digests are now based on the name of the class and the value of Proc#name (if available). Procs or objects containing Procs will have different digests than those created in previous releases.

After much deliberation, I realized that Gibbler cares about the data and not the code. Procs are code, but a reference to a Proc in an instance variable is data. With this change all Proc objects have the same digest. This decision has the side benefit of increasing compatibility between Ruby 1.8, 1.9 & JRuby.

This is the only change between 0.6.4 and 0.7.0 so if you prefer the previous calculation for Procs you can find it in that version.

Happy Digesting!

2009-10-07: Support for freezing and RegexpIn 0.6.4, all Gibbler objects will create a new digest when obj.freeze is called. All subsequent calls to obj.gibbler will return the most recent digest without having to run the calculation again.

I've also added support for Regexp out of the box.

2009-07-20: Digest change for instances of Class, Module, and ProcDigest calculation has changed for Class, Module, and Proc objects. Digests created with Gibbler 0.5.x and earlier will not match the ones created by 0.6.

Class and Module objects were calculating digests based on the output of self.to_s. This was a problem because that string contains a memory address which can change arbitrarily. The new calculation is based on the object class, the length of name, and the name itself. e.g. "Class:6:Object" # => '5620e4a8b10ec6830fece61d33f5d3e9a349b4c2' Proc objects were including the return value of self.binding in the digest calculation. This is not reliable because the binding includes an arbitrary address. The new calculation is based on the class name, the arity, and whether it was created with a lambda. Also note that this change affects the digests for Hashes and Arrays that contain instances of Class, Module, or Proc.

Known Issuesgibbler or gibbled? must be called at least once before gibbled? will be able to return a useful value (otherwise there is no previous digest value to compare to) Digests for Bignum objects are different between Ruby and JRuby. Does anyone know why? Digests for Proc objects are different between Ruby 1.8 and 1.9 because Proc.arity returns different values and 1.8 has no lambda? method. InstallationVia Rubygems, one of:

$ gem install gibbler
    $ gem install delano-gibbleror via download:

gibbler-latest.tar.gz gibbler-latest.zip

What People Are Saying"nice approach - everything is an object, every object is 'gittish'" -- @olgen_morten "gibbler is just awesome" -- @TomK32 "wie cool ist Gibbler eigentlich?" -- @we5 "it's nice idea and implementation!" -- Hristo Hristov More InfoCodes RDocs Sponsor Inspiration ThanksKalin Harvey (krrh) for the early feedback and artistic direction. Alex Peuchert (aaalex) for creating the screencast. CreditsDelano (@solutious.com) LicenseSee: LICENSE.txt