Tidy up implementation.

lib/build/dependency/chain.rb

@@ -18,114 +18,10 @@
 # OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 # THE SOFTWARE.
 
-require 'set'
+require_relative 'resolver'
 
 module Build
 	module Dependency
-		class UnresolvedDependencyError < StandardError
-			def initialize(chain)
-				super "Unresolved dependency chain: #{chain.unresolved.inspect}!"
-
-				@chain = chain
-			end
-
-			attr :chain
-		end
-
-		TOP = Depends.new("<top>").freeze
-
-		class Resolver
-			def initialize
-				@resolved = {}
-				@ordered = []
-				@provisions = []
-				@unresolved = []
-				@conflicts = {}
-			end
-
-			attr :resolved
-			attr :ordered
-			attr :provisions
-			attr :unresolved
-			attr :conflicts
-
-			def freeze
-				return unless frozen?
-
-				@resolved.freeze
-				@ordered.freeze
-				@provisions.freeze
-				@unresolved.freeze
-				@conflicts.freeze
-
-				super
-			end
-
-			protected
-
-			def expand_nested(dependencies, provider)
-				dependencies.each do |dependency|
-					expand(Depends[dependency], provider)
-				end
-			end
-
-			def expand_provision(provision, dependency)
-				provider = provision.provider
-
-				# If the provision was an Alias, make sure to resolve the alias first:
-				if provision.alias?
-					# puts "** Resolving alias #{provision} (#{provision.dependencies.inspect})"
-					expand_nested(provision.dependencies, provider)
-				end
-
-				# puts "** Checking for #{provider.inspect} in #{resolved.inspect}"
-				unless @resolved.include?(provider)
-					# We are now satisfying the provider by expanding all its own dependencies:
-					@resolved[provider] = provision
-
-					# Make sure we satisfy the provider's dependencies first:
-					expand_nested(provider.dependencies, provider)
-
-					# puts "** Appending #{dependency} -> ordered"
-
-					# Add the provider to the ordered list.
-					@ordered << Resolution.new(provision, dependency)
-				end
-
-				# This goes here because we want to ensure 1/ that if 
-				unless provision == nil or provision.alias?
-					# puts "** Appending #{dependency} -> provisions"
-
-					# Add the provision to the set of required provisions.
-					@provisions << provision
-				end
-
-				# For both @ordered and @provisions, we ensure that for [...xs..., x, ...], x is satisfied by ...xs....
-			end
-
-			def expand(dependency, parent)
-				# puts "** Expanding #{dependency.inspect} from #{parent.inspect} (private: #{dependency.private?})"
-
-				if @resolved.include?(dependency)
-					# puts "** Already resolved dependency!"
-
-					return nil
-				end
-
-				# The find_provider method is abstract in this base class.
-				expand_dependency(dependency, parent) do |provision|
-					# We will now satisfy this dependency by satisfying any dependent dependencies, but we no longer need to revisit this one.
-					# puts "** Resolved #{dependency} (#{provision.inspect})"
-					@resolved[dependency] = provision
-
-					expand_provision(provision, dependency)
-				end or begin
-					# puts "** Couldn't find_provider(#{dependency}, #{parent}) -> unresolved"
-					@unresolved << [dependency, parent]
-				end
-			end
-		end
-
 		class Chain < Resolver
 			# An `UnresolvedDependencyError` will be thrown if there are any unresolved dependencies.
 			def self.expand(*args)
@@ -192,24 +88,18 @@ def filter_by_selection(viable_providers)
 				return viable_providers.select{|provider| @selection.include? provider.name}
 			end
 
+			def expand_wildcard(dependency, parent)
+				@providers.flat_map do |provider|
+					provider.filter(dependency).flat_map do |name, provision|
+						expand_dependency(Depends[name], parent)
+					end
+				end
+			end
+
 			# Resolve a dependency into one or more provisions:
 			def expand_dependency(dependency, parent)
 				if dependency.wildcard?
-					matched = false
-
-					@providers.each do |provider|
-						provider.provisions.each do |name, provision|
-							if dependency.match?(name)
-								expand_dependency(Depends[provision.name], parent) do |provision|
-									matched = true
-
-									yield provision
-								end
-							end
-						end
-					end
-
-					return matched
+					return expand_wildcard(dependency, parent)
 				end
 
 				# Mostly, only one package will satisfy the dependency...
@@ -222,9 +112,7 @@ def expand_dependency(dependency, parent)
 					provision = provision_for(provider, dependency)
 
 					# The best outcome, a specific provider was named:
-					yield provision
-
-					return true
+					return [provision]
 				elsif viable_providers.size > 1
 					# ... however in some cases (typically where aliases are being used) an explicit selection must be made for the build to work correctly.
 					explicit_providers = filter_by_selection(viable_providers)
@@ -246,16 +134,14 @@ def expand_dependency(dependency, parent)
 						provision = provision_for(provider, dependency)
 
 						# The best outcome, a specific provider was named:
-						yield provision
-
-						return true
+						return [provision]
 					else
 						# Multiple providers were explicitly mentioned that satisfy the dependency.
 						@conflicts[dependency] = explicit_providers
 					end
 				end
 
-				return false
+				return []
 			end
 
 			def provision_for(provider, dependency)

lib/build/dependency/partial_chain.rb

@@ -83,12 +83,7 @@ def expand(dependency, parent)
 			end
 
 			def expand_dependency(dependency, parent)
-				if provision = @chain.resolved[dependency]
-					yield provision
-					return true
-				end
-
-				return false
+				@chain.resolved[dependency]
 			end
 
 			def provision_for(provider, dependency)

lib/build/dependency/provider.rb

@@ -138,7 +138,7 @@ def dependencies
 			end
 
 			def filter(dependency)
-				provisions.select{|key,value| dependency.match?(key)}
+				provisions.select{|name, provision| dependency.match?(name)}
 			end
 
 			# Does this unit provide the named thing?

lib/build/dependency/resolver.rb

@@ -0,0 +1,133 @@
+# Copyright, 2017, by Samuel G. D. Williams. <http://www.codeotaku.com>
+# 
+# Permission is hereby granted, free of charge, to any person obtaining a copy
+# of this software and associated documentation files (the "Software"), to deal
+# in the Software without restriction, including without limitation the rights
+# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+# copies of the Software, and to permit persons to whom the Software is
+# furnished to do so, subject to the following conditions:
+# 
+# The above copyright notice and this permission notice shall be included in
+# all copies or substantial portions of the Software.
+# 
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+# THE SOFTWARE.
+
+require 'set'
+
+module Build
+	module Dependency
+		class UnresolvedDependencyError < StandardError
+			def initialize(chain)
+				super "Unresolved dependency chain: #{chain.unresolved.inspect}!"
+
+				@chain = chain
+			end
+
+			attr :chain
+		end
+
+		TOP = Depends.new("<top>").freeze
+
+		class Resolver
+			def initialize
+				@resolved = {}
+				@ordered = []
+				@provisions = []
+				@unresolved = []
+				@conflicts = {}
+			end
+
+			attr :resolved
+			attr :ordered
+			attr :provisions
+			attr :unresolved
+			attr :conflicts
+
+			def freeze
+				return unless frozen?
+
+				@resolved.freeze
+				@ordered.freeze
+				@provisions.freeze
+				@unresolved.freeze
+				@conflicts.freeze
+
+				super
+			end
+
+			protected
+
+			def expand_nested(dependencies, provider)
+				dependencies.each do |dependency|
+					expand(Depends[dependency], provider)
+				end
+			end
+
+			def expand_provision(provision, dependency)
+				provider = provision.provider
+
+				# If the provision was an Alias, make sure to resolve the alias first:
+				if provision.alias?
+					# puts "** Resolving alias #{provision} (#{provision.dependencies.inspect})"
+					expand_nested(provision.dependencies, provider)
+				end
+
+				# puts "** Checking for #{provider.inspect} in #{resolved.inspect}"
+				unless @resolved.include?(provider)
+					# We are now satisfying the provider by expanding all its own dependencies:
+					@resolved[provider] = provision
+
+					# Make sure we satisfy the provider's dependencies first:
+					expand_nested(provider.dependencies, provider)
+
+					# puts "** Appending #{dependency} -> ordered"
+
+					# Add the provider to the ordered list.
+					@ordered << Resolution.new(provision, dependency)
+				end
+
+				# This goes here because we want to ensure 1/ that if 
+				unless provision == nil or provision.alias?
+					# puts "** Appending #{dependency} -> provisions"
+
+					# Add the provision to the set of required provisions.
+					@provisions << provision
+				end
+
+				# For both @ordered and @provisions, we ensure that for [...xs..., x, ...], x is satisfied by ...xs....
+			end
+
+			def expand(dependency, parent)
+				# puts "** Expanding #{dependency.inspect} from #{parent.inspect} (private: #{dependency.private?})"
+
+				if @resolved.include?(dependency)
+					# puts "** Already resolved dependency!"
+
+					return nil
+				end
+
+				# The find_provider method is abstract in this base class.
+				provisions = expand_dependency(dependency, parent)
+
+				if provisions.empty?
+					# puts "** Couldn't resolve #{dependency}"
+					@unresolved << [dependency, parent]
+				else
+					# We will now satisfy this dependency by satisfying any dependent dependencies, but we no longer need to revisit this one.
+					# puts "** Resolved #{dependency}"
+					@resolved[dependency] = provisions
+
+					provisions.each do |provision|
+						expand_provision(provision, dependency)
+					end
+				end
+			end
+		end
+	end
+end