brew/Library/Homebrew/os/mac/linkage_checker.rb

require "set"
require "keg"
require "formula"

class LinkageChecker
  attr_reader :keg
  attr_reader :brewed_dylibs, :system_dylibs, :broken_dylibs, :variable_dylibs
  attr_reader :undeclared_deps, :reverse_links

  def initialize(keg)
    @keg = keg
    @brewed_dylibs = Hash.new { |h, k| h[k] = Set.new }
    @system_dylibs = Set.new
    @broken_dylibs = Set.new
    @variable_dylibs = Set.new
    @undeclared_deps = []
    @reverse_links = Hash.new { |h, k| h[k] = Set.new }
    check_dylibs
  end

  def check_dylibs
    @keg.find do |file|
      next if file.symlink? || file.directory?
      next unless file.dylib? || file.mach_o_executable? || file.mach_o_bundle?
      file.dynamically_linked_libraries.each do |dylib|
        @reverse_links[dylib] << file
        if dylib.start_with? "@"
          @variable_dylibs << dylib
        else
          begin
            owner = Keg.for Pathname.new(dylib)
          rescue NotAKegError
            @system_dylibs << dylib
          rescue Errno::ENOENT
            @broken_dylibs << dylib
          else
            @brewed_dylibs[owner.name] << dylib
          end
        end
      end
    end

    begin
      f = Formulary.from_rack(keg.rack)
      f.build = Tab.for_keg(keg)
      filter_out = proc do |dep|
        dep.build? || (dep.optional? && !dep.option_names.any? { |n| f.build.with?(n) })
      end
      declared_deps = f.deps.reject { |dep| filter_out.call(dep) }.map(&:name) +
                      f.requirements.reject { |req| filter_out.call(req) }.map(&:default_formula).compact
      @undeclared_deps = @brewed_dylibs.keys - declared_deps.map { |dep| dep.split("/").last }
      @undeclared_deps -= [f.name]
    rescue FormulaUnavailableError
      opoo "Formula unavailable: #{keg.name}"
    end
  end

  def display_normal_output
    display_items "System libraries", @system_dylibs
    display_items "Homebrew libraries", @brewed_dylibs
    display_items "Variable-referenced libraries", @variable_dylibs
    display_items "Missing libraries", @broken_dylibs
    display_items "Possible undeclared dependencies", @undeclared_deps
  end

  def display_reverse_output
    return if @reverse_links.empty?
    sorted = @reverse_links.sort
    sorted.each do |dylib, files|
      puts dylib
      files.each do |f|
        unprefixed = f.to_s.strip_prefix "#{@keg}/"
        puts "  #{unprefixed}"
      end
      puts unless dylib == sorted.last[0]
    end
  end

  def display_test_output
    display_items "Missing libraries", @broken_dylibs
    puts "No broken dylib links" if @broken_dylibs.empty?
    display_items "Possible undeclared dependencies", @undeclared_deps
    puts "No undeclared dependencies" if @undeclared_deps.empty?
  end

  def broken_dylibs?
    !@broken_dylibs.empty?
  end

  def undeclared_deps?
    !@undeclared_deps.empty?
  end

  private

  # Display a list of things.
  # Things may either be an array, or a hash of (label -> array)
  def display_items(label, things)
    return if things.empty?
    puts "#{label}:"
    if things.is_a? Hash
      things.sort.each do |list_label, list|
        list.sort.each do |item|
          puts "  #{item} (#{list_label})"
        end
      end
    else
      things.sort.each do |item|
        puts "  #{item}"
      end
    end
  end
end