Add Python flow to bindings generation, move dummy-generating IDL files over

Source/bindings/scripts/code_generator_v8.py

+# Copyright (C) 2013 Google Inc. All rights reserved.
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+
+"""Generate Blink V8 bindings (.cpp and .h files).
+
+Given an IR of the IDL files for an interface (produced by the frontend),

[haraken, 2013/07/08 06:06:29]

I'd avoid using the work "IR" and "frontend" since it's not clear what they
mean. You can just say:

  Input: A parsing tree of a given interface X
  Output: V8X.h and V8X.cpp

[Nils Barth (inactive), 2013/07/09 08:48:16]

I've clarified above, where the terms are useful, but we don't need
them here – we can just say "object".
I've reworded slightly (object, not parsing tree), but other have this.

+generates the .cpp and .h files for the binding.
+
+FIXME: Currently a stub, as part of landing the parser and code generator

[haraken, 2013/07/08 06:06:29]

Let's explain our working plan here. In other words, you can explain:

- We temporarily have two build flows:
  [1] deprecated_idl_parser.pl => deprecated_code_generator_v8.pm
  [2] idl_parser.py => code_generator_v8.py

- We will move IDL files from the build flow [1] to the build flow [2]
incrementally.

[Nils Barth (inactive), 2013/07/09 08:48:16]

Done!
(Please feel free to suggest rewordings.)

+incrementally. Only implements generation of dummy .cpp and .h files.
+"""
+
+import os.path
+
+
+def generate_dummy_header_and_cpp(target_interface_name, output_directory):
+    header_basename = 'V8%s.h' % target_interface_name
+    cpp_basename = 'V8%s.cpp' % target_interface_name
+    header_fullname = os.path.join(output_directory, header_basename)
+    cpp_fullname = os.path.join(output_directory, cpp_basename)
+    contents = """/*
+    This file is generated just to tell build scripts that {header_basename} and
+    {cpp_basename} are created for {target_interface_name}.idl, and thus
+    prevent the build scripts from trying to generate {header_basename} and
+    {cpp_basename} at every build. This file must not be tried to compile.
+*/

[haraken, 2013/07/08 06:06:29]

You might want to use the jinja template for this. Please ask koji-san how to
use jinja.

[Nils Barth (inactive), 2013/07/09 08:48:16]

That's a really good point – we don't want manual templates here.

I should actually be able to get rid of these dummy files by
making some changes to the build (so the dependency files are
dependencies but not compiled), so this should go away soon.

So for now let's just use this function, as it's short and going to die;
it's mostly useful because it gives us real files to run in the
Python flow.
(We don't want to also introduce Jinja in this CL!)

OTOH, if Koji would like to switch this to a Jinja template as a
first step of landing his Jinja-based code generator, I'm happy
to leave it around for a while.

+""".format(**locals())
+    with open(header_fullname, 'w') as header_file:
+        header_file.write(contents)
+    with open(cpp_fullname, 'w') as cpp_file:
+        cpp_file.write(contents)