os/mac: optionally use ruby_macho.

- and branch for dylib_id_and_dylibs
- add branches for dylib id changing and change_install_name
- rename MachO module to HomebrewMachO to prevent namespace clashes
  with MachO in ruby-macho. this will eventually be replaced entirely
  with direct calls to ruby-macho methods
- break ruby-macho implementation out into separate RubyMachO module,
  and include either RubyMachO or CctoolsMachO (the original
  implementation) based on the HOMEBREW_RUBY_MACHO env var
- move ArchitectureListExtension and RubyMachO into separate files
- create {ruby_,cctools_,,}relocate.rb for isolation of different
  methods of mach-o relocation (ruby-macho vs. cctools)
- fill in require_install_name_tool? for ruby_relocate.rb
- rename {ruby_,cctools_,,}relocate.rb to keg, isolate requires in
  os/mac

Closes Homebrew/homebrew#45001.

Signed-off-by: Mike McQuaid <mike@mikemcquaid.com>

1 files changed, 103 insertions, 0 deletions

diff --git a/Library/Homebrew/os/mac/ruby_mach.rb b/Library/Homebrew/os/mac/ruby_mach.rb
new file mode 100644
index 000000000..3cd0ac0b9
--- /dev/null
+++ b/Library/Homebrew/os/mac/ruby_mach.rb
@@ -0,0 +1,103 @@
+require "vendor/macho/macho"
+require "os/mac/architecture_list"
+
+module RubyMachO
+  # @private
+  def macho
+    @macho ||= begin
+      MachO.open(to_s)
+    end
+  end
+
+  # @private
+  def mach_data
+    @mach_data ||= begin
+      machos = []
+      mach_data = []
+
+      if MachO.fat_magic?(macho.magic)
+        machos = macho.machos
+      else
+        machos << macho
+      end
+
+      machos.each do |m|
+        arch = case m.cputype
+        when "CPU_TYPE_I386" then :i386
+        when "CPU_TYPE_X86_64" then :x86_64
+        when "CPU_TYPE_POWERPC" then :ppc7400
+        when "CPU_TYPE_POWERPC64" then :ppc64
+        else :dunno
+        end
+
+        type = case m.filetype
+        when "MH_EXECUTE" then :executable
+        when "MH_DYLIB" then :dylib
+        when "MH_BUNDLE" then :bundle
+        else :dunno
+        end
+
+        mach_data << { :arch => arch, :type => type }
+      end
+
+      mach_data
+    rescue
+      []
+    end
+  end
+
+  def archs
+    mach_data.map { |m| m.fetch :arch }.extend(ArchitectureListExtension)
+  end
+
+  def arch
+    case archs.length
+    when 0 then :dunno
+    when 1 then archs.first
+    else :universal
+    end
+  end
+
+  def universal?
+    arch == :universal
+  end
+
+  def i386?
+    arch == :i386
+  end
+
+  def x86_64?
+    arch == :x86_64
+  end
+
+  def ppc7400?
+    arch == :ppc7400
+  end
+
+  def ppc64?
+    arch == :ppc64
+  end
+
+  # @private
+  def dylib?
+    mach_data.any? { |m| m.fetch(:type) == :dylib }
+  end
+
+  # @private
+  def mach_o_executable?
+    mach_data.any? { |m| m.fetch(:type) == :executable }
+  end
+
+  # @private
+  def mach_o_bundle?
+    mach_data.any? { |m| m.fetch(:type) == :bundle }
+  end
+
+  def dynamically_linked_libraries
+    macho.linked_dylibs
+  end
+
+  def dylib_id
+    macho.dylib_id
+  end
+end