Shrink requirements.rb

1 files changed, 82 insertions, 0 deletions

diff --git a/Library/Homebrew/requirements/mpi_dependency.rb b/Library/Homebrew/requirements/mpi_dependency.rb
new file mode 100644
index 000000000..b51efc303
--- /dev/null
+++ b/Library/Homebrew/requirements/mpi_dependency.rb
@@ -0,0 +1,82 @@
+require 'requirement'
+
+# There are multiple implementations of MPI-2 available.
+# http://www.mpi-forum.org/
+# This requirement is used to find an appropriate one.
+class MPIDependency < Requirement
+
+  attr_reader :lang_list
+
+  fatal true
+
+  env :userpaths
+
+  def initialize *lang_list
+    @lang_list = lang_list
+    @non_functional = []
+    @unknown_langs = []
+    super()
+  end
+
+  def mpi_wrapper_works? compiler
+    compiler = which compiler
+    return false if compiler.nil? or not compiler.executable?
+
+    # Some wrappers are non-functional and will return a non-zero exit code
+    # when invoked for version info.
+    #
+    # NOTE: A better test may be to do a small test compilation a la autotools.
+    quiet_system compiler, '--version'
+  end
+
+  satisfy do
+    @lang_list.each do |lang|
+      case lang
+      when :cc, :cxx, :f90, :f77
+        compiler = 'mpi' + lang.to_s
+        @non_functional << compiler unless mpi_wrapper_works? compiler
+      else
+        @unknown_langs << lang.to_s
+      end
+    end
+    @unknown_langs.empty? and @non_functional.empty?
+  end
+
+  env do
+    # Set environment variables to help configure scripts find MPI compilers.
+    # Variable names taken from:
+    # http://www.gnu.org/software/autoconf-archive/ax_mpi.html
+    @lang_list.each do |lang|
+      compiler = 'mpi' + lang.to_s
+      mpi_path = which compiler
+
+      # Fortran 90 environment var has a different name
+      compiler = 'MPIFC' if lang == :f90
+      ENV[compiler.upcase] = mpi_path
+    end
+  end
+
+  def message
+    if not @unknown_langs.empty?
+      <<-EOS.undent
+        There is no MPI compiler wrapper for:
+            #{@unknown_langs.join ', '}
+
+        The following values are valid arguments to `MPIDependency.new`:
+            :cc, :cxx, :f90, :f77
+        EOS
+    else
+      <<-EOS.undent
+        Homebrew could not locate working copies of the following MPI compiler
+        wrappers:
+            #{@non_functional.join ', '}
+
+        If you have a MPI installation, please ensure the bin folder is on your
+        PATH and that all the wrappers are functional. Otherwise, a MPI
+        installation can be obtained from homebrew by *picking one* of the
+        following formulae:
+            open-mpi, mpich2
+        EOS
+    end
+  end
+end