Start on simple resolving. We don't try to fix conflicts yet to keep things…

Start on simple resolving. We don't try to fix conflicts yet to keep things simple, so for now that's up to the user.

examples/Podfile

+#dependency 'ASIHTTPRequest', '1.8'
+dependency 'ASIWebPageRequest', '= 1.8'
+
 # is part of ASIHTTPRequest 1.8 and 1.8.1
 dependency 'Reachability' #, '>= 2.0'
 
 # is part of ASIHTTPRequest
-dependency 'ASIWebPageRequest', '>= 1.8'
+#dependency 'ASIWebPageRequest', '>= 1.8'
+#dependency 'ASIWebPageRequest', '= 1.8'
 
 # this should fail the ASIHTTPRequest 1.8.1 hard requirement
 #dependency 'ASIWebPageRequest', '1.8.0'
@@ -10,4 +14,5 @@ dependency 'ASIWebPageRequest', '>= 1.8'
 # we have a hard requirement here so:
 # * the Reachability dependency should be taken from this version
 # * the ASIWebPageRequest dependency requirement matches this one so should work
-dependency 'ASIHTTPRequest', '1.8.1'
+#dependency 'ASIHTTPRequest', '1.8.1'
+dependency 'ASIHTTPRequest', '>= 1.8'

lib/cocoa_pods.rb

@@ -2,6 +2,7 @@ module Pod
   autoload :Command,       'cocoa_pods/command'
   autoload :Config,        'cocoa_pods/config'
   autoload :Dependency,    'cocoa_pods/dependency'
+  autoload :Resolver,      'cocoa_pods/resolver'
   autoload :Source,        'cocoa_pods/source'
   autoload :Spec,          'cocoa_pods/specification'
   autoload :Specification, 'cocoa_pods/specification'

lib/cocoa_pods/command/install.rb

@@ -4,7 +4,7 @@ module Pod
       def run
         if spec = Specification.from_podfile(podfile)
           p spec
-          spec.install!
+          Resolver.new(spec).resolve
         else
           $stderr.puts "No Podfile found in current working directory."
         end

lib/cocoa_pods/dependency.rb

@@ -4,6 +4,5 @@ require 'rubygems/dependency'
 
 module Pod
   class Dependency < Gem::Dependency
-
   end
 end

lib/cocoa_pods/source.rb

@@ -16,9 +16,7 @@ module Pod
 
     def search(dependency)
       if dir = @repo.children.find { |c| c.basename.to_s == dependency.name }
-        set = Specification::Set.new(dir)
-        set.add_dependency(dependency)
-        set
+        Specification::Set.new(dir)
       end
     end
   end

lib/cocoa_pods/specification.rb

@@ -62,7 +62,8 @@ module Pod
     end
 
     def part_of(name, *version_requirements)
-      @part_of = Dependency.new(name, *version_requirements)
+      #@part_of = Dependency.new(name, *version_requirements)
+      dependency(name, *version_requirements)
     end
 
     def source_files(*patterns)
@@ -75,7 +76,6 @@ module Pod
 
     attr_reader :dependencies
     def dependency(name, *version_requirements)
-      #version = args || [">= 0"]
       @dependencies << Dependency.new(name, *version_requirements)
     end
 
@@ -87,31 +87,14 @@ module Pod
 
     def to_s
       if from_podfile?
-        "#<#{self.class.name} for podfile at `#{@defined_in_file}'>"
+        "podfile at `#{@defined_in_file}'"
       else
-        "#<#{self.class.name} for `#{@name}' version `#{@version}'>"
+        "`#{@name}' version `#{@version}'"
       end
     end
-    alias_method :inspect, :to_s
 
-    # TODO move to seperate installer class
-    def install!
-      #p @name, @version, @authors, @dependencies
-      @dependency_sets = @dependencies.map { |dep| Source.search(dep) }.flatten
-      @dependency_sets.each do |set|
-        p set
-        p set.podspec
-      end
-    end
-
-    private
-
-    def attr(name, arg)
-      if arg.nil? || arg.empty?
-        instance_variable_get("@#{name}")
-      else
-        instance_variable_set("@#{name}", block_given? ? yield : arg)
-      end
+    def inspect
+      "#<#{self.class.name} for #{to_s}>"
     end
   end
 

lib/cocoa_pods/specification/set.rb

@@ -3,10 +3,21 @@ module Pod
     class Set
       def initialize(pod_dir)
         @pod_dir = pod_dir
+        @required_by = []
       end
 
-      def add_dependency(dependency)
-        @dependency = dependency
+      def required_by(specification, dependency)
+        unless @required_by.empty? || dependency.requirement.satisfied_by?(required_version)
+          # TODO add graph that shows which dependencies led to this.
+          required_by = @required_by.map(&:first).join(', ')
+          raise "#{specification} tries to activate `#{dependency}', " \
+                "but already activated version `#{required_version}' by #{required_by}."
+        end
+        @required_by << [specification, dependency]
+      end
+
+      def dependency
+        @required_by.inject(Dependency.new(name)) { |previous, (_, dep)| previous.merge(dep) }
       end
 
       def name
@@ -23,12 +34,16 @@ module Pod
 
       # Return the first version that matches the current dependency.
       def required_version
-        unless v = versions.find { |v| @dependency.match?(name, v) }
-          raise "Required version (#{@dependency}) not found for `#{name}'."
+        unless v = versions.find { |v| dependency.match?(name, v) }
+          raise "Required version (#{dependency}) not found for `#{name}'."
         end
         v
       end
 
+      def ==(other)
+        self.class === other && name == other.name
+      end
+
       def to_s
         "#<#{self.class.name} for `#{name}' with required version `#{required_version}'>"
       end
@@ -39,7 +54,7 @@ module Pod
       # Returns Pod::Version instances, for each version directory, sorted from
       # lowest version to highest.
       def versions
-        @pod_dir.children.map { |v| Version.new(v.basename) }.sort
+        @pod_dir.children.map { |v| Version.new(v.basename) }.sort.reverse
       end
     end
   end