JezK
Edit File: dependency_graph.rb
# frozen_string_literal: true require_relative '../../../../tsort' require_relative 'dependency_graph/log' require_relative 'dependency_graph/vertex' module Gem::Resolver::Molinillo # A directed acyclic graph that is tuned to hold named dependencies class DependencyGraph include Enumerable # Enumerates through the vertices of the graph. # @return [Array<Vertex>] The graph's vertices. def each return vertices.values.each unless block_given? vertices.values.each { |v| yield v } end include Gem::TSort # @!visibility private alias tsort_each_node each # @!visibility private def tsort_each_child(vertex, &block) vertex.successors.each(&block) end # Topologically sorts the given vertices. # @param [Enumerable<Vertex>] vertices the vertices to be sorted, which must # all belong to the same graph. # @return [Array<Vertex>] The sorted vertices. def self.tsort(vertices) TSort.tsort( lambda { |b| vertices.each(&b) }, lambda { |v, &b| (v.successors & vertices).each(&b) } ) end # A directed edge of a {DependencyGraph} # @attr [Vertex] origin The origin of the directed edge # @attr [Vertex] destination The destination of the directed edge # @attr [Object] requirement The requirement the directed edge represents Edge = Struct.new(:origin, :destination, :requirement) # @return [{String => Vertex}] the vertices of the dependency graph, keyed # by {Vertex#name} attr_reader :vertices # @return [Log] the op log for this graph attr_reader :log # Initializes an empty dependency graph def initialize @vertices = {} @log = Log.new end # Tags the current state of the dependency as the given tag # @param [Object] tag an opaque tag for the current state of the graph # @return [Void] def tag(tag) log.tag(self, tag) end # Rewinds the graph to the state tagged as `tag` # @param [Object] tag the tag to rewind to # @return [Void] def rewind_to(tag) log.rewind_to(self, tag) end # Initializes a copy of a {DependencyGraph}, ensuring that all {#vertices} # are properly copied. # @param [DependencyGraph] other the graph to copy. def initialize_copy(other) super @vertices = {} @log = other.log.dup traverse = lambda do |new_v, old_v| return if new_v.outgoing_edges.size == old_v.outgoing_edges.size old_v.outgoing_edges.each do |edge| destination = add_vertex(edge.destination.name, edge.destination.payload) add_edge_no_circular(new_v, destination, edge.requirement) traverse.call(destination, edge.destination) end end other.vertices.each do |name, vertex| new_vertex = add_vertex(name, vertex.payload, vertex.root?) new_vertex.explicit_requirements.replace(vertex.explicit_requirements) traverse.call(new_vertex, vertex) end end # @return [String] a string suitable for debugging def inspect "#{self.class}:#{vertices.values.inspect}" end # @param [Hash] options options for dot output. # @return [String] Returns a dot format representation of the graph def to_dot(options = {}) edge_label = options.delete(:edge_label) raise ArgumentError, "Unknown options: #{options.keys}" unless options.empty? dot_vertices = [] dot_edges = [] vertices.each do |n, v| dot_vertices << " #{n} [label=\"{#{n}|#{v.payload}}\"]" v.outgoing_edges.each do |e| label = edge_label ? edge_label.call(e) : e.requirement dot_edges << " #{e.origin.name} -> #{e.destination.name} [label=#{label.to_s.dump}]" end end dot_vertices.uniq! dot_vertices.sort! dot_edges.uniq! dot_edges.sort! dot = dot_vertices.unshift('digraph G {').push('') + dot_edges.push('}') dot.join("\n") end # @param [DependencyGraph] other # @return [Boolean] whether the two dependency graphs are equal, determined # by a recursive traversal of each {#root_vertices} and its # {Vertex#successors} def ==(other) return false unless other return true if equal?(other) vertices.each do |name, vertex| other_vertex = other.vertex_named(name) return false unless other_vertex return false unless vertex.payload == other_vertex.payload return false unless other_vertex.successors.to_set == vertex.successors.to_set end end # @param [String] name # @param [Object] payload # @param [Array<String>] parent_names # @param [Object] requirement the requirement that is requiring the child # @return [void] def add_child_vertex(name, payload, parent_names, requirement) root = !parent_names.delete(nil) { true } vertex = add_vertex(name, payload, root) vertex.explicit_requirements << requirement if root parent_names.each do |parent_name| parent_vertex = vertex_named(parent_name) add_edge(parent_vertex, vertex, requirement) end vertex end # Adds a vertex with the given name, or updates the existing one. # @param [String] name # @param [Object] payload # @return [Vertex] the vertex that was added to `self` def add_vertex(name, payload, root = false) log.add_vertex(self, name, payload, root) end # Detaches the {#vertex_named} `name` {Vertex} from the graph, recursively # removing any non-root vertices that were orphaned in the process # @param [String] name # @return [Array<Vertex>] the vertices which have been detached def detach_vertex_named(name) log.detach_vertex_named(self, name) end # @param [String] name # @return [Vertex,nil] the vertex with the given name def vertex_named(name) vertices[name] end # @param [String] name # @return [Vertex,nil] the root vertex with the given name def root_vertex_named(name) vertex = vertex_named(name) vertex if vertex && vertex.root? end # Adds a new {Edge} to the dependency graph # @param [Vertex] origin # @param [Vertex] destination # @param [Object] requirement the requirement that this edge represents # @return [Edge] the added edge def add_edge(origin, destination, requirement) if destination.path_to?(origin) raise CircularDependencyError.new(path(destination, origin)) end add_edge_no_circular(origin, destination, requirement) end # Deletes an {Edge} from the dependency graph # @param [Edge] edge # @return [Void] def delete_edge(edge) log.delete_edge(self, edge.origin.name, edge.destination.name, edge.requirement) end # Sets the payload of the vertex with the given name # @param [String] name the name of the vertex # @param [Object] payload the payload # @return [Void] def set_payload(name, payload) log.set_payload(self, name, payload) end private # Adds a new {Edge} to the dependency graph without checking for # circularity. # @param (see #add_edge) # @return (see #add_edge) def add_edge_no_circular(origin, destination, requirement) log.add_edge_no_circular(self, origin.name, destination.name, requirement) end # Returns the path between two vertices # @raise [ArgumentError] if there is no path between the vertices # @param [Vertex] from # @param [Vertex] to # @return [Array<Vertex>] the shortest path from `from` to `to` def path(from, to) distances = Hash.new(vertices.size + 1) distances[from.name] = 0 predecessors = {} each do |vertex| vertex.successors.each do |successor| if distances[successor.name] > distances[vertex.name] + 1 distances[successor.name] = distances[vertex.name] + 1 predecessors[successor] = vertex end end end path = [to] while before = predecessors[to] path << before to = before break if to == from end unless path.last.equal?(from) raise ArgumentError, "There is no path from #{from.name} to #{to.name}" end path.reverse end end end