class Gem::Resolver::Molinillo::DependencyGraph

A directed acyclic graph that is tuned to hold named dependencies

Constants

Edge: 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

Attributes

log[R]

@return [Log] the op log for this graph

vertices[R]

@return [{String => Vertex}] the vertices of the dependency graph, keyed

by {Vertex#name}

Public Class Methods

new() click to toggle source

Initializes an empty dependency graph

# File lib/rubygems/resolver/molinillo/lib/molinillo/dependency_graph.rb, line 55
def initialize
  @vertices = {}
  @log = Log.new
end

tsort(vertices) click to toggle source

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.

# File lib/rubygems/resolver/molinillo/lib/molinillo/dependency_graph.rb, line 34
def self.tsort(vertices)
  Gem::TSort.tsort(
    lambda { |b| vertices.each(&b) },
    lambda { |v, &b| (v.successors & vertices).each(&b) }
  )
end

Public Instance Methods

==(other) click to toggle source

@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}

# File lib/rubygems/resolver/molinillo/lib/molinillo/dependency_graph.rb, line 130
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

add_child_vertex(name, payload, parent_names, requirement) click to toggle source

@param [String] name @param [Object] payload @param [Array<String>] parent_names @param [Object] requirement the requirement that is requiring the child @return [void]

# File lib/rubygems/resolver/molinillo/lib/molinillo/dependency_graph.rb, line 146
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

add_edge(origin, destination, requirement) click to toggle source

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

# File lib/rubygems/resolver/molinillo/lib/molinillo/dependency_graph.rb, line 191
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

add_vertex(name, payload, root = false) click to toggle source

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`

# File lib/rubygems/resolver/molinillo/lib/molinillo/dependency_graph.rb, line 161
def add_vertex(name, payload, root = false)
  log.add_vertex(self, name, payload, root)
end

delete_edge(edge) click to toggle source

Deletes an {Edge} from the dependency graph @param [Edge] edge @return [Void]

# File lib/rubygems/resolver/molinillo/lib/molinillo/dependency_graph.rb, line 201
def delete_edge(edge)
  log.delete_edge(self, edge.origin.name, edge.destination.name, edge.requirement)
end

detach_vertex_named(name) click to toggle source

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

# File lib/rubygems/resolver/molinillo/lib/molinillo/dependency_graph.rb, line 169
def detach_vertex_named(name)
  log.detach_vertex_named(self, name)
end

each() { |v| ... } click to toggle source

Enumerates through the vertices of the graph. @return [Array<Vertex>] The graph’s vertices.

# File lib/rubygems/resolver/molinillo/lib/molinillo/dependency_graph.rb, line 15
def each
  return vertices.values.each unless block_given?
  vertices.values.each { |v| yield v }
end

Also aliased as: tsort_each_node

initialize_copy(other) click to toggle source

Initializes a copy of a {DependencyGraph}, ensuring that all {#vertices} are properly copied. @param [DependencyGraph] other the graph to copy.

Calls superclass method

# File lib/rubygems/resolver/molinillo/lib/molinillo/dependency_graph.rb, line 77
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

inspect() click to toggle source

@return [String] a string suitable for debugging

# File lib/rubygems/resolver/molinillo/lib/molinillo/dependency_graph.rb, line 97
def inspect
  "#{self.class}:#{vertices.values.inspect}"
end

rewind_to(tag) click to toggle source

Rewinds the graph to the state tagged as ‘tag` @param [Object] tag the tag to rewind to @return [Void]

# File lib/rubygems/resolver/molinillo/lib/molinillo/dependency_graph.rb, line 70
def rewind_to(tag)
  log.rewind_to(self, tag)
end

root_vertex_named(name) click to toggle source

@param [String] name @return [Vertex,nil] the root vertex with the given name

# File lib/rubygems/resolver/molinillo/lib/molinillo/dependency_graph.rb, line 181
def root_vertex_named(name)
  vertex = vertex_named(name)
  vertex if vertex && vertex.root?
end

set_payload(name, payload) click to toggle source

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]

# File lib/rubygems/resolver/molinillo/lib/molinillo/dependency_graph.rb, line 209
def set_payload(name, payload)
  log.set_payload(self, name, payload)
end

tag(tag) click to toggle source

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]

# File lib/rubygems/resolver/molinillo/lib/molinillo/dependency_graph.rb, line 63
def tag(tag)
  log.tag(self, tag)
end

to_dot(options = {}) click to toggle source

@param [Hash] options options for dot output. @return [String] Returns a dot format representation of the graph

# File lib/rubygems/resolver/molinillo/lib/molinillo/dependency_graph.rb, line 103
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

tsort_each_child(vertex, &block) click to toggle source

@!visibility private

# File lib/rubygems/resolver/molinillo/lib/molinillo/dependency_graph.rb, line 26
def tsort_each_child(vertex, &block)
  vertex.successors.each(&block)
end

tsort_each_node()

@!visibility private

Alias for: each

vertex_named(name) click to toggle source

@param [String] name @return [Vertex,nil] the vertex with the given name

# File lib/rubygems/resolver/molinillo/lib/molinillo/dependency_graph.rb, line 175
def vertex_named(name)
  vertices[name]
end

Private Instance Methods

add_edge_no_circular(origin, destination, requirement) click to toggle source

Adds a new {Edge} to the dependency graph without checking for circularity. @param (see add_edge) @return (see add_edge)

# File lib/rubygems/resolver/molinillo/lib/molinillo/dependency_graph.rb, line 219
def add_edge_no_circular(origin, destination, requirement)
  log.add_edge_no_circular(self, origin.name, destination.name, requirement)
end

path(from, to) click to toggle source

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`

# File lib/rubygems/resolver/molinillo/lib/molinillo/dependency_graph.rb, line 228
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