Factor out a base class from RuntimeFeatureWriter

Source/core/scripts/in_generator.py

+# Copyright (C) 2013 Google Inc. All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are
+# met:
+#
+#     * Redistributions of source code must retain the above copyright
+# notice, this list of conditions and the following disclaimer.
+#     * Redistributions in binary form must reproduce the above
+# copyright notice, this list of conditions and the following disclaimer
+# in the documentation and/or other materials provided with the
+# distribution.
+#     * Neither the name of Google Inc. nor the names of its
+# contributors may be used to endorse or promote products derived from
+# this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+import os.path
+import shutil
+
+from in_file import InFile
+
+
+class Writer(object):
+    # Subclasses should override.
+    class_name = None

[eseidel, 2013/04/30 21:07:29]

Why is this a class-level property?

[abarth-chromium, 2013/04/30 21:09:41]

We might end up making it an instance-level property as we iterate on this code.
 At the moment, RuntimeFeatureWriter always computes this as a constant.  I can
make it a class-level constant in the derived class as well if you like.

+    defaults = None

[eseidel, 2013/04/30 21:07:29]

This makes more sense as a class-level property.

+
+    def __init__(self, in_file_path):
+        self.in_file = InFile.load_from_path(in_file_path, self.defaults)
+
+    # Subclasses should override.
+    def generate_header(self):
+        raise NotImplementedError
+
+    # Subclasses should override.
+    def generate_implementation(self):
+        raise NotImplementedError
+
+    def _forcibly_create_text_file_at_path_with_contents(self, file_path, contents):
+        # FIXME: This method can be made less force-full anytime after 6/1/2013.
+        # A gyp error was briefly checked into the tree, causing
+        # a directory to have been generated in place of one of
+        # our output files.  Clean up after that error so that
+        # all users don't need to clobber their output directories.
+        shutil.rmtree(file_path, ignore_errors=True)
+        # The build system should ensure our output directory exists, but just in case.
+        directory = os.path.dirname(file_path)
+        if not os.path.exists(directory):
+            os.makedirs(directory)
+
+        with open(file_path, "w") as file_to_write:
+            file_to_write.write(contents)
+
+    def write_header(self, output_dir):
+        header_path = os.path.join(output_dir, self.class_name + ".h")
+        self._forcibly_create_text_file_at_path_with_contents(header_path, self.generate_header())
+
+    def write_implmentation(self, output_dir):
+        implmentation_path = os.path.join(output_dir, self.class_name + ".cpp")
+        self._forcibly_create_text_file_at_path_with_contents(implmentation_path, self.generate_implementation())
+
+
+class Maker(object):
+    def __init__(self, writer_class):
+        self._writer_class = writer_class
+
+    def main(self, argv):
+        script_name = os.path.basename(argv[0])
+        args = argv[1:]
+        if len(args) < 1:
+            print "USAGE: %i INPUT_FILE [OUTPUT_DIRECTORY]" % script_name
+            exit(1)
+        output_dir = args[1] if len(args) > 1 else os.getcwd()
+
+        writer = self._writer_class(args[0])
+        writer.write_header(output_dir)
+        writer.write_implmentation(output_dir)