add a Directory builder - close #27

lib/rscons.rb

@@ -8,6 +8,7 @@ require_relative "rscons/version"
 # default builders
 require_relative "rscons/builders/command"
 require_relative "rscons/builders/cfile"
+require_relative "rscons/builders/directory"
 require_relative "rscons/builders/disassemble"
 require_relative "rscons/builders/library"
 require_relative "rscons/builders/object"
@@ -22,6 +23,7 @@ module Rscons
   DEFAULT_BUILDERS = [
     :Command,
     :CFile,
+    :Directory,
     :Disassemble,
     :Library,
     :Object,

lib/rscons/builders/directory.rb

@@ -0,0 +1,31 @@
+module Rscons
+  module Builders
+    # The Directory builder creates a directory.
+    class Directory < Builder
+
+      # Run the builder to produce a build target.
+      #
+      # @param target [String] Target file name.
+      # @param sources [Array<String>] Source file name(s).
+      # @param cache [Cache] The Cache object.
+      # @param env [Environment] The Environment executing the builder.
+      # @param vars [Hash,VarSet] Extra construction variables.
+      #
+      # @return [String,false]
+      #   Name of the target file on success or false on failure.
+      def run(target, sources, cache, env, vars)
+        if File.directory?(target)
+          target
+        elsif File.exists?(target)
+          $stderr.puts "Error: `#{target}' already exists and is not a directory"
+          false
+        else
+          puts "Directory #{target}"
+          cache.mkdir_p(target)
+          target
+        end
+      end
+
+    end
+  end
+end

spec/build_tests_spec.rb

@@ -798,4 +798,38 @@ EOF
     ])
   end
 
+  context "Directory builder" do
+    it "creates the requested directory" do
+      test_dir("simple")
+      Rscons::Environment.new do |env|
+        env.Directory("teh_dir")
+      end
+      expect(File.directory?("teh_dir")).to be_truthy
+      expect(lines).to eq(["Directory teh_dir"])
+    end
+
+    it "succeeds when the requested directory already exists" do
+      test_dir("simple")
+      FileUtils.mkdir("teh_dir")
+      Rscons::Environment.new do |env|
+        env.Directory("teh_dir")
+      end
+      expect(File.directory?("teh_dir")).to be_truthy
+      expect(lines).to eq([])
+    end
+
+    it "fails when the target path is a file" do
+      test_dir("simple")
+      FileUtils.touch("teh_dir")
+      expect do
+        Rscons::Environment.new do |env|
+          env.Directory("teh_dir")
+        end
+      end.to raise_error /Failed to build teh_dir/
+      expect(lines).to eq([
+        "Error: `teh_dir' already exists and is not a directory",
+      ])
+    end
+  end
+
 end