Decouple Resource from SoftwareSpec

Library/Homebrew/formula.rb

@@ -720,11 +720,11 @@ class Formula
     end
 
     # Define a named resource using a SoftwareSpec style block
-    def resource res_name, &block
-      raise DuplicateResourceError.new(res_name) if resources.has_key?(res_name)
-      spec = SoftwareSpec.new
-      spec.instance_eval(&block)
-      resources[res_name] = Resource.new(res_name, spec)
+    def resource name, &block
+      raise DuplicateResourceError.new(name) if resources.has_key?(name)
+      resource = Resource.new(name)
+      resource.instance_eval(&block)
+      resources[name] = resource
     end
 
     def dependencies

Library/Homebrew/resource.rb

@@ -1,3 +1,7 @@
+require 'download_strategy'
+require 'checksum'
+require 'version'
+
 # A Resource describes a tarball that a formula needs in addition
 # to the formula's own download.
 class Resource
@@ -7,16 +11,23 @@ class Resource
   # This is the resource name
   attr_reader :name
 
-  def initialize name, spec
+  attr_reader :checksum, :mirrors, :specs, :using
+
+  def initialize name
     @name = name
-    @spec = spec
+    @url = nil
+    @version = nil
+    @mirrors = []
+    @specs = {}
+    @checksum = nil
+    @using = nil
   end
 
   # Formula name must be set after the DSL, as we have no access to the
   # formula name before initialization of the formula
   def set_owner owner
     @owner = owner
-    @downloader = @spec.download_strategy.new("#{owner}--#{name}", @spec)
+    @downloader = download_strategy.new("#{owner}--#{name}", self)
   end
 
   # Download the resource
@@ -36,6 +47,10 @@ class Resource
     end
   end
 
+  def download_strategy
+    @download_strategy ||= DownloadStrategyDetector.detect(url, using)
+  end
+
   def cached_download
     @downloader.cached_location
   end
@@ -49,6 +64,51 @@ class Resource
   end
 
   def verify_download_integrity fn
-    @spec.verify_download_integrity(fn)
+    fn.verify_checksum(checksum)
+  rescue ChecksumMissingError
+    opoo "Cannot verify package integrity"
+    puts "The formula did not provide a download checksum"
+    puts "For your reference the SHA1 is: #{fn.sha1}"
+  rescue ChecksumMismatchError => e
+    e.advice = <<-EOS.undent
+    Archive: #{fn}
+    (To retry an incomplete download, remove the file above.)
+    EOS
+    raise e
+  end
+
+  Checksum::TYPES.each do |cksum|
+    class_eval <<-EOS, __FILE__, __LINE__ + 1
+      def #{cksum}(val)
+        @checksum = Checksum.new(:#{cksum}, val)
+      end
+    EOS
+  end
+
+  def url val=nil, specs={}
+    return @url if val.nil?
+    @url = val
+    @using = specs.delete(:using)
+    @specs.merge!(specs)
+  end
+
+  def version val=nil
+    @version ||= detect_version(val)
+  end
+
+  def mirror val
+    mirrors << val
+  end
+
+  private
+
+  def detect_version(val)
+    case val
+    when nil    then Version.detect(url, specs)
+    when String then Version.new(val)
+    when Hash   then Version.new_with_scheme(*val.shift)
+    else
+      raise TypeError, "version '#{val.inspect}' should be a string"
+    end
   end
 end