1 files changed, 66 insertions, 0 deletions
diff --git a/Library/Homebrew/compat/requirements/mpi_requirement.rb b/Library/Homebrew/compat/requirements/mpi_requirement.rb
new file mode 100644
index 000000000..065b56c8b
--- /dev/null
+++ b/Library/Homebrew/compat/requirements/mpi_requirement.rb
@@ -0,0 +1,66 @@
+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 MPIRequirement < Requirement
+  attr_reader :lang_list
+
+  fatal true
+
+  default_formula "open-mpi"
+
+  env :userpaths
+
+  # This method must accept varargs rather than an array for
+  # backwards compatibility with formulae that call it directly.
+  def initialize(*tags)
+    @non_functional = []
+    @unknown_langs = []
+    @lang_list = [:cc, :cxx, :f77, :f90] & tags
+    tags -= @lang_list
+    super(tags)
+  end
+
+  def mpi_wrapper_works?(compiler)
+    compiler = which compiler
+    return false if compiler.nil? || !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
+
+  def inspect
+    "#<#{self.class.name}: #{name.inspect} #{tags.inspect} lang_list=#{@lang_list.inspect}>"
+  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? && @non_functional.empty?
+  end
+
+  env do
+    # Set environment variables to help configure scripts find MPI compilers.
+    # Variable names taken from:
+    # https://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
+end