Class: DepSelector::Package

Inherits:
Object
  • Object
show all
Defined in:
lib/dep_selector/package.rb

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(dependency_graph, name) ⇒ Package

Returns a new instance of Package.



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# File 'lib/dep_selector/package.rb', line 27

def initialize(dependency_graph, name)
  @dependency_graph = dependency_graph
  @name = name
  @versions = []
end

Instance Attribute Details

#dependency_graph ⇒ Object (readonly)

Returns the value of attribute dependency_graph.



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# File 'lib/dep_selector/package.rb', line 25

def dependency_graph
  @dependency_graph
end

#name ⇒ Object (readonly)

Returns the value of attribute name.



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# File 'lib/dep_selector/package.rb', line 25

def name
  @name
end

#versions ⇒ Object (readonly)

Returns the value of attribute versions.



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# File 'lib/dep_selector/package.rb', line 25

def versions
  @versions
end

Instance Method Details

#[](version_or_constraint) ⇒ Object

Given a version, this method returns the corresonding PackageVersion. Given a version constraint, this method returns an array of matching PackageVersions. – TODO [cw,2011/2/4]: rationalize this with DenselyPackedSet#[]



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# File 'lib/dep_selector/package.rb', line 48

def [](version_or_constraint)
  # version constraints must abide the include? contract
  if version_or_constraint.respond_to?(:include?)
    versions.select do |ver|
      version_or_constraint.include?(ver)
    end
  else
    versions.find{|pkg_version| pkg_version.version == version_or_constraint}
  end
end

#add_version(version) ⇒ Object 



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# File 'lib/dep_selector/package.rb', line 33

def add_version(version)
  versions << (pv = PackageVersion.new(self, version))
  pv
end

#densely_packed_versions ⇒ Object

Note: only invoke this method after all PackageVersions have been added



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# File 'lib/dep_selector/package.rb', line 39

def densely_packed_versions
  @densely_packed_versions ||= DenselyPackedSet.new(versions.map{|pkg_version| pkg_version.version})
end

#eql?(o) ⇒ Boolean Also known as: ==

Returns:

  • (Boolean) 


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# File 'lib/dep_selector/package.rb', line 108

def eql?(o)
  # TODO [cw,2011/2/7]: this is really shallow. should implement
  # == for DependencyGraph
  self.class == o.class && name == o.name
end

#gecode_package_id ⇒ Object

Note: only invoke this method after all PackageVersions have been added



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# File 'lib/dep_selector/package.rb', line 75

def gecode_package_id
  # Note: gecode does naive bounds propagation at every post,
  # which means that any package with exactly one version is
  # considered bound and its dependencies propagated even though
  # there might not be a solution constraint that requires that
  # package to be bound, which means that otherwise-irrelevant
  # constraints (e.g. A1->B1 when the solution constraint is B=2
  # and there is nothing to induce a dependency on A) can cause
  # unsatisfiability. Therefore, we want every package to have at
  # least two versions, one of which is neither the target of
  # other packages' dependencies nor induces other
  # dependencies. Package version id -1 serves this purpose.
  #
  # TODO [cw, 2011/2/22]: Do we likewise want to leave packages
  # with no versions (the target of an invalid dependency) with
  # two versions in order to allow the solver to explore the
  # invalid portion of the state space instead of naively limiting
  # it for the purposes of having failure count heuristics?
  max = densely_packed_versions.range.max || -1
  @gecode_package_id ||= dependency_graph.gecode_wrapper.add_package(-1, max, 0)
end

#generate_gecode_wrapper_constraints ⇒ Object 



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# File 'lib/dep_selector/package.rb', line 97

def generate_gecode_wrapper_constraints
  # if this is a valid package (has versions), we don't need to
  # explicitly call gecode_package_id, because they will do it for
  # us; however, if this package isn't valid (it only exists as an
  # invalid dependency and thus has no versions), the solver gets
  # confused, because we won't have generated its package id by
  # the time it starts solving.
  gecode_package_id
  versions.each{|version| version.generate_gecode_wrapper_constraints }
end

#to_s(incl_densely_packed_versions = false) ⇒ Object 



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# File 'lib/dep_selector/package.rb', line 64

def to_s(incl_densely_packed_versions = false)
  components = []
  components << "Package #{name}"
  if incl_densely_packed_versions
    components << " (#{densely_packed_versions.range})"
  end
  versions.each{|version| components << "\n  #{version.to_s(incl_densely_packed_versions)}"}
  components.flatten.join
end

#valid? ⇒ Boolean

A Package is considered valid if it has at least one version

Returns:

  • (Boolean) 


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# File 'lib/dep_selector/package.rb', line 60

def valid?
  versions.any?
end