| Current File : //opt/alt/ruby27/share/rubygems/rubygems/resolver/molinillo/lib/molinillo/resolution.rb |
# frozen_string_literal: true
module Gem::Resolver::Molinillo
class Resolver
# A specific resolution from a given {Resolver}
class Resolution
# A conflict that the resolution process encountered
# @attr [Object] requirement the requirement that immediately led to the conflict
# @attr [{String,Nil=>[Object]}] requirements the requirements that caused the conflict
# @attr [Object, nil] existing the existing spec that was in conflict with
# the {#possibility}
# @attr [Object] possibility the spec that was unable to be activated due
# to a conflict
# @attr [Object] locked_requirement the relevant locking requirement.
# @attr [Array<Array<Object>>] requirement_trees the different requirement
# trees that led to every requirement for the conflicting name.
# @attr [{String=>Object}] activated_by_name the already-activated specs.
Conflict = Struct.new(
:requirement,
:requirements,
:existing,
:possibility,
:locked_requirement,
:requirement_trees,
:activated_by_name
)
# @return [SpecificationProvider] the provider that knows about
# dependencies, requirements, specifications, versions, etc.
attr_reader :specification_provider
# @return [UI] the UI that knows how to communicate feedback about the
# resolution process back to the user
attr_reader :resolver_ui
# @return [DependencyGraph] the base dependency graph to which
# dependencies should be 'locked'
attr_reader :base
# @return [Array] the dependencies that were explicitly required
attr_reader :original_requested
# Initializes a new resolution.
# @param [SpecificationProvider] specification_provider
# see {#specification_provider}
# @param [UI] resolver_ui see {#resolver_ui}
# @param [Array] requested see {#original_requested}
# @param [DependencyGraph] base see {#base}
def initialize(specification_provider, resolver_ui, requested, base)
@specification_provider = specification_provider
@resolver_ui = resolver_ui
@original_requested = requested
@base = base
@states = []
@iteration_counter = 0
@parents_of = Hash.new { |h, k| h[k] = [] }
end
# Resolves the {#original_requested} dependencies into a full dependency
# graph
# @raise [ResolverError] if successful resolution is impossible
# @return [DependencyGraph] the dependency graph of successfully resolved
# dependencies
def resolve
start_resolution
while state
break unless state.requirements.any? || state.requirement
indicate_progress
if state.respond_to?(:pop_possibility_state) # DependencyState
debug(depth) { "Creating possibility state for #{requirement} (#{possibilities.count} remaining)" }
state.pop_possibility_state.tap do |s|
if s
states.push(s)
activated.tag(s)
end
end
end
process_topmost_state
end
activated.freeze
ensure
end_resolution
end
# @return [Integer] the number of resolver iterations in between calls to
# {#resolver_ui}'s {UI#indicate_progress} method
attr_accessor :iteration_rate
private :iteration_rate
# @return [Time] the time at which resolution began
attr_accessor :started_at
private :started_at
# @return [Array<ResolutionState>] the stack of states for the resolution
attr_accessor :states
private :states
private
# Sets up the resolution process
# @return [void]
def start_resolution
@started_at = Time.now
handle_missing_or_push_dependency_state(initial_state)
debug { "Starting resolution (#{@started_at})\nUser-requested dependencies: #{original_requested}" }
resolver_ui.before_resolution
end
# Ends the resolution process
# @return [void]
def end_resolution
resolver_ui.after_resolution
debug do
"Finished resolution (#{@iteration_counter} steps) " \
"(Took #{(ended_at = Time.now) - @started_at} seconds) (#{ended_at})"
end
debug { 'Unactivated: ' + Hash[activated.vertices.reject { |_n, v| v.payload }].keys.join(', ') } if state
debug { 'Activated: ' + Hash[activated.vertices.select { |_n, v| v.payload }].keys.join(', ') } if state
end
require 'rubygems/resolver/molinillo/lib/molinillo/state'
require 'rubygems/resolver/molinillo/lib/molinillo/modules/specification_provider'
require 'rubygems/resolver/molinillo/lib/molinillo/delegates/resolution_state'
require 'rubygems/resolver/molinillo/lib/molinillo/delegates/specification_provider'
include Gem::Resolver::Molinillo::Delegates::ResolutionState
include Gem::Resolver::Molinillo::Delegates::SpecificationProvider
# Processes the topmost available {RequirementState} on the stack
# @return [void]
def process_topmost_state
if possibility
attempt_to_activate
else
create_conflict if state.is_a? PossibilityState
unwind_for_conflict until possibility && state.is_a?(DependencyState)
end
end
# @return [Object] the current possibility that the resolution is trying
# to activate
def possibility
possibilities.last
end
# @return [RequirementState] the current state the resolution is
# operating upon
def state
states.last
end
# Creates the initial state for the resolution, based upon the
# {#requested} dependencies
# @return [DependencyState] the initial state for the resolution
def initial_state
graph = DependencyGraph.new.tap do |dg|
original_requested.each { |r| dg.add_vertex(name_for(r), nil, true).tap { |v| v.explicit_requirements << r } }
dg.tag(:initial_state)
end
requirements = sort_dependencies(original_requested, graph, {})
initial_requirement = requirements.shift
DependencyState.new(
initial_requirement && name_for(initial_requirement),
requirements,
graph,
initial_requirement,
initial_requirement && search_for(initial_requirement),
0,
{}
)
end
# Unwinds the states stack because a conflict has been encountered
# @return [void]
def unwind_for_conflict
debug(depth) { "Unwinding for conflict: #{requirement} to #{state_index_for_unwind / 2}" }
conflicts.tap do |c|
sliced_states = states.slice!((state_index_for_unwind + 1)..-1)
raise VersionConflict.new(c) unless state
activated.rewind_to(sliced_states.first || :initial_state) if sliced_states
state.conflicts = c
index = states.size - 1
@parents_of.each { |_, a| a.reject! { |i| i >= index } }
end
end
# @return [Integer] The index to which the resolution should unwind in the
# case of conflict.
def state_index_for_unwind
current_requirement = requirement
existing_requirement = requirement_for_existing_name(name)
index = -1
[current_requirement, existing_requirement].each do |r|
until r.nil?
current_state = find_state_for(r)
if state_any?(current_state)
current_index = states.index(current_state)
index = current_index if current_index > index
break
end
r = parent_of(r)
end
end
index
end
# @return [Object] the requirement that led to `requirement` being added
# to the list of requirements.
def parent_of(requirement)
return unless requirement
return unless index = @parents_of[requirement].last
return unless parent_state = @states[index]
parent_state.requirement
end
# @return [Object] the requirement that led to a version of a possibility
# with the given name being activated.
def requirement_for_existing_name(name)
return nil unless activated.vertex_named(name).payload
states.find { |s| s.name == name }.requirement
end
# @return [ResolutionState] the state whose `requirement` is the given
# `requirement`.
def find_state_for(requirement)
return nil unless requirement
states.reverse_each.find { |i| requirement == i.requirement && i.is_a?(DependencyState) }
end
# @return [Boolean] whether or not the given state has any possibilities
# left.
def state_any?(state)
state && state.possibilities.any?
end
# @return [Conflict] a {Conflict} that reflects the failure to activate
# the {#possibility} in conjunction with the current {#state}
def create_conflict
vertex = activated.vertex_named(name)
locked_requirement = locked_requirement_named(name)
requirements = {}
unless vertex.explicit_requirements.empty?
requirements[name_for_explicit_dependency_source] = vertex.explicit_requirements
end
requirements[name_for_locking_dependency_source] = [locked_requirement] if locked_requirement
vertex.incoming_edges.each { |edge| (requirements[edge.origin.payload] ||= []).unshift(edge.requirement) }
activated_by_name = {}
activated.each { |v| activated_by_name[v.name] = v.payload if v.payload }
conflicts[name] = Conflict.new(
requirement,
requirements,
vertex.payload,
possibility,
locked_requirement,
requirement_trees,
activated_by_name
)
end
# @return [Array<Array<Object>>] The different requirement
# trees that led to every requirement for the current spec.
def requirement_trees
vertex = activated.vertex_named(name)
vertex.requirements.map { |r| requirement_tree_for(r) }
end
# @return [Array<Object>] the list of requirements that led to
# `requirement` being required.
def requirement_tree_for(requirement)
tree = []
while requirement
tree.unshift(requirement)
requirement = parent_of(requirement)
end
tree
end
# Indicates progress roughly once every second
# @return [void]
def indicate_progress
@iteration_counter += 1
@progress_rate ||= resolver_ui.progress_rate
if iteration_rate.nil?
if Time.now - started_at >= @progress_rate
self.iteration_rate = @iteration_counter
end
end
if iteration_rate && (@iteration_counter % iteration_rate) == 0
resolver_ui.indicate_progress
end
end
# Calls the {#resolver_ui}'s {UI#debug} method
# @param [Integer] depth the depth of the {#states} stack
# @param [Proc] block a block that yields a {#to_s}
# @return [void]
def debug(depth = 0, &block)
resolver_ui.debug(depth, &block)
end
# Attempts to activate the current {#possibility}
# @return [void]
def attempt_to_activate
debug(depth) { 'Attempting to activate ' + possibility.to_s }
existing_node = activated.vertex_named(name)
if existing_node.payload
debug(depth) { "Found existing spec (#{existing_node.payload})" }
attempt_to_activate_existing_spec(existing_node)
else
attempt_to_activate_new_spec
end
end
# Attempts to activate the current {#possibility} (given that it has
# already been activated)
# @return [void]
def attempt_to_activate_existing_spec(existing_node)
existing_spec = existing_node.payload
if requirement_satisfied_by?(requirement, activated, existing_spec)
new_requirements = requirements.dup
push_state_for_requirements(new_requirements, false)
else
return if attempt_to_swap_possibility
create_conflict
debug(depth) { "Unsatisfied by existing spec (#{existing_node.payload})" }
unwind_for_conflict
end
end
# Attempts to swp the current {#possibility} with the already-activated
# spec with the given name
# @return [Boolean] Whether the possibility was swapped into {#activated}
def attempt_to_swap_possibility
activated.tag(:swap)
vertex = activated.vertex_named(name)
activated.set_payload(name, possibility)
if !vertex.requirements.
all? { |r| requirement_satisfied_by?(r, activated, possibility) } ||
!new_spec_satisfied?
activated.rewind_to(:swap)
return
end
fixup_swapped_children(vertex)
activate_spec
end
# Ensures there are no orphaned successors to the given {vertex}.
# @param [DependencyGraph::Vertex] vertex the vertex to fix up.
# @return [void]
def fixup_swapped_children(vertex) # rubocop:disable Metrics/CyclomaticComplexity
payload = vertex.payload
deps = dependencies_for(payload).group_by(&method(:name_for))
vertex.outgoing_edges.each do |outgoing_edge|
requirement = outgoing_edge.requirement
parent_index = @parents_of[requirement].last
succ = outgoing_edge.destination
matching_deps = Array(deps[succ.name])
dep_matched = matching_deps.include?(requirement)
# only push the current index when it was originally required by the
# same named spec
if parent_index && states[parent_index].name == name
@parents_of[requirement].push(states.size - 1)
end
if matching_deps.empty? && !succ.root? && succ.predecessors.to_a == [vertex]
debug(depth) { "Removing orphaned spec #{succ.name} after swapping #{name}" }
succ.requirements.each { |r| @parents_of.delete(r) }
removed_names = activated.detach_vertex_named(succ.name).map(&:name)
requirements.delete_if do |r|
# the only removed vertices are those with no other requirements,
# so it's safe to delete only based upon name here
removed_names.include?(name_for(r))
end
elsif !dep_matched
debug(depth) { "Removing orphaned dependency #{requirement} after swapping #{name}" }
# also reset if we're removing the edge, but only if its parent has
# already been fixed up
@parents_of[requirement].push(states.size - 1) if @parents_of[requirement].empty?
activated.delete_edge(outgoing_edge)
requirements.delete(requirement)
end
end
end
# Attempts to activate the current {#possibility} (given that it hasn't
# already been activated)
# @return [void]
def attempt_to_activate_new_spec
if new_spec_satisfied?
activate_spec
else
create_conflict
unwind_for_conflict
end
end
# @return [Boolean] whether the current spec is satisfied as a new
# possibility.
def new_spec_satisfied?
unless requirement_satisfied_by?(requirement, activated, possibility)
debug(depth) { 'Unsatisfied by requested spec' }
return false
end
locked_requirement = locked_requirement_named(name)
locked_spec_satisfied = !locked_requirement ||
requirement_satisfied_by?(locked_requirement, activated, possibility)
debug(depth) { 'Unsatisfied by locked spec' } unless locked_spec_satisfied
locked_spec_satisfied
end
# @param [String] requirement_name the spec name to search for
# @return [Object] the locked spec named `requirement_name`, if one
# is found on {#base}
def locked_requirement_named(requirement_name)
vertex = base.vertex_named(requirement_name)
vertex && vertex.payload
end
# Add the current {#possibility} to the dependency graph of the current
# {#state}
# @return [void]
def activate_spec
conflicts.delete(name)
debug(depth) { "Activated #{name} at #{possibility}" }
activated.set_payload(name, possibility)
require_nested_dependencies_for(possibility)
end
# Requires the dependencies that the recently activated spec has
# @param [Object] activated_spec the specification that has just been
# activated
# @return [void]
def require_nested_dependencies_for(activated_spec)
nested_dependencies = dependencies_for(activated_spec)
debug(depth) { "Requiring nested dependencies (#{nested_dependencies.join(', ')})" }
nested_dependencies.each do |d|
activated.add_child_vertex(name_for(d), nil, [name_for(activated_spec)], d)
parent_index = states.size - 1
parents = @parents_of[d]
parents << parent_index if parents.empty?
end
push_state_for_requirements(requirements + nested_dependencies, !nested_dependencies.empty?)
end
# Pushes a new {DependencyState} that encapsulates both existing and new
# requirements
# @param [Array] new_requirements
# @return [void]
def push_state_for_requirements(new_requirements, requires_sort = true, new_activated = activated)
new_requirements = sort_dependencies(new_requirements.uniq, new_activated, conflicts) if requires_sort
new_requirement = new_requirements.shift
new_name = new_requirement ? name_for(new_requirement) : ''.freeze
possibilities = new_requirement ? search_for(new_requirement) : []
handle_missing_or_push_dependency_state DependencyState.new(
new_name, new_requirements, new_activated,
new_requirement, possibilities, depth, conflicts.dup
)
end
# Pushes a new {DependencyState}.
# If the {#specification_provider} says to
# {SpecificationProvider#allow_missing?} that particular requirement, and
# there are no possibilities for that requirement, then `state` is not
# pushed, and the node in {#activated} is removed, and we continue
# resolving the remaining requirements.
# @param [DependencyState] state
# @return [void]
def handle_missing_or_push_dependency_state(state)
if state.requirement && state.possibilities.empty? && allow_missing?(state.requirement)
state.activated.detach_vertex_named(state.name)
push_state_for_requirements(state.requirements.dup, false, state.activated)
else
states.push(state).tap { activated.tag(state) }
end
end
end
end
end