ioquatix/build-dependency

# 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_relative 'set'

module Build
    module Dependency
        def self.included(klass)
            klass.include(Provider)
        end
        
        # A provision is a thing which satisfies a dependency.
        Provision = Struct.new(:name, :provider, :value) do
            def each_dependency(&block)
                self.provider.dependencies.each(&block)
            end
            
            def alias?
                false
            end
            
            def to_s
                "provides #{name.inspect}"
            end
        end
        
        Alias = Struct.new(:name, :provider, :dependencies) do
            def each_dependency(&block)
                return to_enum(&block) unless block_given?
                
                dependencies.each do |name|
                    yield Depends.new(name)
                end
            end
            
            def alias?
                true
            end
            
            def to_s
                "provides #{name.inspect} -> #{dependencies.collect(&:inspect).join(', ')}"
            end
        end
        
        Resolution = Struct.new(:provision, :dependency) do
            def name
                dependency.name
            end
            
            def provider
                provision.provider
            end
            
            def to_s
                "resolution #{provider.name.inspect} -> #{dependency.name.inspect}"
            end
        end
        
        Depends = Struct.new(:name, :options) do
            def initialize(name, **options)
                super(name, options)
            end
            
            def wildcard?
                self.name.is_a?(String) and self.name.include?('*')
            end
            
            def match?(name)
                if wildcard? and name.is_a?(String)
                    File.fnmatch?(self.name, name)
                else
                    self.name == name
                end
            end
            
            def to_s
                if options.any?
                    "depends on #{name.inspect} #{options.inspect}"
                else
                    "depends on #{name.inspect}"
                end
            end
            
            def public?
                !!options[:public]
            end
            
            def private?
                !!options[:private]
            end
            
            def alias?
                name.is_a?(Symbol)
            end
            
            class << self
                undef []
                
                def [](name_or_dependency)
                    name_or_dependency.is_a?(self) ? name_or_dependency : self.new(name_or_dependency)
                end
            end
        end
        
        module Provider
            def freeze
                return unless frozen?
                
                provisions.freeze
                dependencies.freeze
                
                super
            end
            
            # Assign a priority.
            def priority= value
                @priority = value
            end
            
            # The default priority.
            def priority
                @priority ||= 0
            end
            
            # @return Hash<String, Provision> a table of named provisions.
            def provisions
                @provisions ||= {}
            end
            
            # @return [IdentitySet<Dependency>]
            def dependencies
                @dependencies ||= Set.new
            end
            
            def filter(dependency)
                provisions.select{|name, provision| dependency.match?(name)}
            end
            
            # Does this unit provide the named thing?
            def provides?(dependency)
                provisions.key?(dependency.name)
            end
            
            def provision_for(dependency)
                return provisions[dependency.name]
            end
            
            def resolution_for(dependency)
                return Resolution.new(provision_for(dependency), dependency)
            end
            
            # Add one or more provisions to the provider.
            # @param [Array<String>] names the named provisions to add.
            # @param [Hash<Symbol, Array>] aliases the aliases to add.
            # @example A named provision.
            #     target.provides "Compiler/clang" do
            #         cxx "clang"
            #     end
            # @example A symbolic provision.
            #     target.provides compiler: "Compiler/clang"
            def provides(*names, **aliases, &block)
                names.each do |name|
                    provisions[name] = Provision.new(name, self, block)
                end
                
                aliases.each do |name, dependencies|
                    provisions[name] = Alias.new(name, self, Array(dependencies))
                end
            end
            
            # Add one or more dependencies to the provider.
            # @param [Array<String>] names the dependency names to add.
            # @example A named dependency.
            #     target.depends "Compiler/clang"
            # @example A symbolic dependency.
            #     target.depends :compiler
            def depends(*names, **options)
                names.each do |name|
                    dependencies << Depends.new(name, **options)
                end
            end
            
            def depends?(name)
                dependencies.include?(name)
            end
        end
    end
end