diff options
Diffstat (limited to 'lib/rubygems/vendor/molinillo/lib/molinillo/dependency_graph.rb')
| -rw-r--r-- | lib/rubygems/vendor/molinillo/lib/molinillo/dependency_graph.rb | 255 |
1 files changed, 255 insertions, 0 deletions
diff --git a/lib/rubygems/vendor/molinillo/lib/molinillo/dependency_graph.rb b/lib/rubygems/vendor/molinillo/lib/molinillo/dependency_graph.rb new file mode 100644 index 0000000000..2dbbc589dc --- /dev/null +++ b/lib/rubygems/vendor/molinillo/lib/molinillo/dependency_graph.rb @@ -0,0 +1,255 @@ +# frozen_string_literal: true + +require_relative '../../../../vendored_tsort' + +require_relative 'dependency_graph/log' +require_relative 'dependency_graph/vertex' + +module Gem::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) + Gem::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 |