1 files changed, 19 insertions, 0 deletions
diff --git a/ext/coverage/lib/coverage.rb b/ext/coverage/lib/coverage.rb
new file mode 100644
index 0000000000..4bd20e22cb
--- /dev/null
+++ b/ext/coverage/lib/coverage.rb
@@ -0,0 +1,19 @@
+require "coverage.so"
+
+module Coverage
+  # call-seq:
+  #   line_stub(file) -> array
+  #
+  # A simple helper function that creates the "stub" of line coverage
+  # from a given source code.
+  def self.line_stub(file)
+    lines = File.foreach(file).map { nil }
+    iseqs = [RubyVM::InstructionSequence.compile_file(file)]
+    until iseqs.empty?
+      iseq = iseqs.pop
+      iseq.trace_points.each {|n, type| lines[n - 1] = 0 if type == :line }
+      iseq.each_child {|child| iseqs << child }
+    end
+    lines
+  end
+end