Class: Fixes

Inherits:

Object

• Object
• Fixes

show all

Extended by:

Enumerable

Defined in:

app/models/fixes.rb

Overview

Defined Under Namespace

Classes: Failure

Constant Summary

FILE_DIR =

Directory that fix files are stored in

File.join(Rails.root, 'system', 'fixes')

Class Method Summary (collapse)

• + (Lambda) [](identifier)

  Convenience accessor - Fixes gets back the fix in question.

• + (Object) definitions(&block)

  Definitions block, which sets the context to a Fix instantiation Within this block, #fix_for can be used to define new fixes.

• + (Object) each(&block)

  Iterates over fixes as hash.

• + (Boolean) key?(key)

  Delegate #key? on the class to the internal hash.

• + (Hash{String => Lambda}) preflights

  Expose preflights variable for use in Run.

• + (Object) refresh_fixes(dir = nil)

  For each file in the FILE_DIR, create or replace a fix Uses the file's name to determine fix name.

• + (Hash{String => Lambda}) reorder

  Ensures that order-dependent fixes are ordered properly Depends on Ruby's ordered hash semantics For implementation details, search on “topological sort” and “Kahn's Algorithm”.

Instance Method Summary (collapse)

• - (Lambda) fix_for(identifier, depends_on: [], preflight: false, &block)

  Define an individual fix.

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# File 'app/models/fixes.rb', line 102

def self.[](identifier)
  @@fixes[identifier]
end

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# File 'app/models/fixes.rb', line 58

def self.definitions(&block)
  instance = new
  instance.instance_eval(&block)
  @@fixes = reorder
end

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# File 'app/models/fixes.rb', line 40

def each(&block)
  return @@fixes.to_enum unless block_given?
  @@fixes.each do |member|
    yield member
  end
end

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# File 'app/models/fixes.rb', line 52

def self.key?(key)
  @@fixes.key?(key)
end

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# File 'app/models/fixes.rb', line 31

def self.preflights
  @@preflights
end

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# File 'app/models/fixes.rb', line 143

def self.refresh_fixes(dir = nil)
  @@fixes.clear
  @@constraints.clear
  @@preflights.clear
  definitions do
    Dir[File.join(dir || FILE_DIR, '*.rb')].each do |fname|
      fixes_content = IO.read(fname)
      raise "File `#{fname}` does not contain fixes" unless fixes_content.index('fix_for')
      eval fixes_content, nil, fname, 1
    end
  end
end

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# File 'app/models/fixes.rb', line 68

def self.reorder
  order = {}.with_indifferent_access
  edges = @@constraints.dup
  incoming = edges.map(&:last).uniq
  nodes = edges.flatten.uniq
  s = Set.new(nodes.reject{|e| incoming.include? e})
  while !s.empty?
    n = s.first
    s.delete n
    order[n] = @@fixes[n]
    nodes.each do |m|
      if edges.member? [n,m]
        edges.delete [n,m]
        s.add m if edges.none? {|(_,y)| y == m}
      end
    end
  end
  raise(<<-ERROR_TXT) if edges.any?
Cyclical dependency found in your fixes.  Please inspect your @depends_on statements.
The following edges remain in your dependency graph after processing:
#{edges}
  ERROR_TXT

  # Add fixes without dependency concerns
  @@fixes.keys.reject {|fix_id| order.key? fix_id}.each do |fix_id|
    order[fix_id] = @@fixes[fix_id]
  end

  order
end

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# File 'app/models/fixes.rb', line 120

def fix_for(identifier, depends_on: [], preflight: false, &block)
  unless preflight
    depends_on.each do |dep|
      @@constraints << [dep, identifier]
    end

    @@fixes[identifier] = -> (xml) do
      @xml = xml
      yield
      @xml
    end
  else
    @@preflights[identifier] = -> (xml) do
      @xml = xml
      yield
      @xml
    end
  end
end