Merge branch 'master' into spec-refactor

Get the cache for testing.

* master:
  Enable caching for specs and remove configurable git cache size.
  Save Git chaches in ~/Library/Caches/CocoaPods/Git.
  [Downloader::Git] Skip cache pull if ref is available.
  Restored Pod::Downloader::Git::GitHub.
  [Git] Fix for Travis errors.
  [Git] Increased default cache to 500Mb.
  [Downloader::Git] Completed cache support
  [Git<<Downloader] Fix for url hash
  [Downloader::Git] Cache repos

lib/cocoapods/config.rb

@@ -14,6 +14,7 @@ module Pod
     attr_accessor :clean, :verbose, :silent
     attr_accessor :generate_docs, :doc_install, :force_doc
     attr_accessor :integrate_targets
+    attr_accessor :git_cache_size
 
     alias_method :clean?,             :clean
     alias_method :verbose?,           :verbose

lib/cocoapods/downloader/git.rb

 require 'open-uri'
 require 'tempfile'
 require 'zlib'
+require 'digest/sha1'
 
 module Pod
   class Downloader
     class Git < Downloader
+      include Config::Mixin
       executable :git
 
+      MAX_CACHE_SIZE = 500
+
       def download
+        prepare_cache
+        puts '->'.green << ' Cloning git repo' if config.verbose?
         if options[:tag]
           download_tag
         elsif options[:commit]
@@ -15,16 +21,83 @@ module Pod
         else
           download_head
         end
+        removed_cached_repos_if_needed
+      end
+
+      def prepare_cache
+        unless cache_exist?
+          puts '->'.green << " Creating cache git repo (#{cache_path})" if config.verbose?
+          cache_path.rmtree if cache_path.exist?
+          cache_path.mkpath
+          git "clone '#{url}' #{cache_path}"
+        end
+      end
+
+      def removed_cached_repos_if_needed
+        return unless caches_dir.exist?
+        Dir.chdir(caches_dir) do
+          repos = Pathname.new(caches_dir).children.select { |c| c.directory? }.sort_by(&:ctime)
+          while caches_size >= MAX_CACHE_SIZE && !repos.empty?
+            dir = repos.shift
+            puts '->'.yellow << " Removing git cache for `#{origin_url(dir)}'" if config.verbose?
+            dir.rmtree
+          end
+        end
+      end
+
+      def cache_path
+        @cache_path ||= caches_dir + "#{Digest::SHA1.hexdigest(url.to_s)}"
+      end
+
+      def cache_exist?
+        cache_path.exist? && origin_url(cache_path) == url
+      end
+
+      def origin_url(dir)
+        Dir.chdir(dir) { `git config remote.origin.url`.chomp }
+      end
+
+      def caches_dir
+        Pathname.new(File.expand_path("~/Library/Caches/CocoaPods/Git"))
+      end
+
+      def clone_url
+        cache_path
+      end
+
+      def caches_size
+        # expressed in Mb
+        `du -cm`.split("\n").last.to_i
+      end
+
+      def update_cache
+        puts '->'.green << " Updating cache git repo (#{cache_path})" if config.verbose?
+        Dir.chdir(cache_path) do
+          git "reset --hard HEAD"
+          git "clean -d -x -f"
+          git "pull"
+        end
+      end
+
+      def ensure_ref_exists(ref)
+        Dir.chdir(cache_path) { git "rev-list --max-count=1 #{ref}" }
+        return if $? == 0
+        # Skip pull if not needed
+        update_cache
+        Dir.chdir(cache_path) { git "rev-list --max-count=1 #{ref}" }
+        raise Informative, "[!] Cache unable to find git reference `#{ref}' for `#{url}'.".red unless $? == 0
       end
 
       def download_head
-        git "clone '#{url}' '#{target_path}'"
+        update_cache
+        git "clone '#{clone_url}' '#{target_path}'"
       end
 
       def download_tag
+        ensure_ref_exists(options[:tag])
         Dir.chdir(target_path) do
           git "init"
-          git "remote add origin '#{url}'"
+          git "remote add origin '#{clone_url}'"
           git "fetch origin tags/#{options[:tag]}"
           git "reset --hard FETCH_HEAD"
           git "checkout -b activated-pod-commit"
@@ -32,8 +105,8 @@ module Pod
       end
 
       def download_commit
-        git "clone '#{url}' '#{target_path}'"
-
+        ensure_ref_exists(options[:commit])
+        git "clone '#{clone_url}' '#{target_path}'"
         Dir.chdir(target_path) do
           git "checkout -b activated-pod-commit #{options[:commit]}"
         end
@@ -71,7 +144,7 @@ module Pod
         original_url, username, reponame = *(url.match(/[:\/]([\w\-]+)\/([\w\-]+)\.git/).to_a)
         "https://github.com/#{username}/#{reponame}/tarball/#{id}"
       end
-      
+
       def tmp_path
         target_path + "tarball.tar.gz"
       end

spec/unit/downloader_spec.rb

@@ -19,7 +19,7 @@ describe "Pod::Downloader" do
     downloader.url.should == 'http://banana-corp.local/banana-lib.git'
     downloader.options.should == { :tag => 'v1.0' }
   end
-  
+
   it 'returns a github downloader when the :git URL is on github' do
     pod = Pod::LocalPod.new(fixture_spec('banana-lib/BananaLib.podspec'), temporary_sandbox, Pod::Platform.ios)
     pod.specification.stubs(:source).returns(:git => "git://github.com/CocoaPods/CocoaPods")
@@ -36,21 +36,21 @@ describe Pod::Downloader::GitHub do
     ))
     downloader.tarball_url_for('master').should == "https://github.com/CocoaPods/CocoaPods/tarball/master"
   end
-  
+
   it 'can convert private HTTP repository URLs to the tarball URL' do
     downloader = Pod::Downloader.for_pod(stub_pod_with_source(
       :git => "https://lukeredpath@github.com/CocoaPods/CocoaPods.git"
     ))
     downloader.tarball_url_for('master').should == "https://github.com/CocoaPods/CocoaPods/tarball/master"
   end
-  
+
   it 'can convert private SSH repository URLs to the tarball URL' do
     downloader = Pod::Downloader.for_pod(stub_pod_with_source(
       :git => "git@github.com:CocoaPods/CocoaPods.git"
     ))
     downloader.tarball_url_for('master').should == "https://github.com/CocoaPods/CocoaPods/tarball/master"
   end
-  
+
   it 'can convert public git protocol repository URLs to the tarball URL' do
     downloader = Pod::Downloader.for_pod(stub_pod_with_source(
       :git => "git://github.com/CocoaPods/CocoaPods.git"