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

Source/bindings/scripts/idl_compiler.py

+#!/usr/bin/python
+# 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.
+
+"""Compile an .idl file to Blink V8 bindings (.h and .cpp files).
+
+We are porting the IDL compiler from Perl to Python. The plan is as follows.
+We will temporarily have two build flows (see ../derived_sources.gyp):
+[1] Perl: deprecated_generate_bindings.pl, which calls:
+    deprecated_idl_parser.pm => deprecated_code_generator_v8.pm
+[2] Python: idl_compiler.py, which calls:
+    frontend (lexer => parser => read_idl.py) => code_generator_v8.py

[haraken, 2013/07/10 04:06:50]

read_idl.py (lexer => parser => validater) => code_generator_v8.py ?

- Let's stop using abstract wording like "frontend". It's not clear for
newcomers what it means.

- I'd rename read_idl.py to parse_idl_file.py, but it's just a bikeshedding.

[Nils Barth (inactive), 2013/07/10 06:00:15]

Done, discussed in comments.

+
+We will move IDL files from the Perl build flow [1] to the Python build flow [2]
+incrementally.
+First we will land the build changes and idl_compiler.py (in one CL).
+Next we will land the full frontend (in one CL), which parses all IDL files.
+Finally we will incrementally land the code generator (in several CLs),
+moving IDL files to the Python build flow as the code generator is completed.
+"""
+import optparse
+import os
+import shlex
+import sys
+
+import read_idl
+import code_generator_v8
+
+
+def parse_options():
+    parser = optparse.OptionParser()
+    parser.add_option('--additional-idl-files')
+    parser.add_option('--idl-attributes-file')
+    parser.add_option('--include', dest='idl_directories', action='append')
+    parser.add_option('--output-directory')
+    parser.add_option('--interface-dependencies-file')
+    parser.add_option('--verbose', action='store_true', default=False)
+    parser.add_option('--write-file-only-if-changed', type='int')
+    # ensure output comes last, so command line easy to parse via regexes
+    parser.disable_interspersed_args()
+
+    options, args = parser.parse_args()
+    if options.output_directory is None:
+        parser.error('Must specify output directory using --output-directory.')
+    if options.additional_idl_files is not None:
+        # additional_idl_files is passed as a string with varied (shell-style)
+        # quoting, hence needs parsing.
+        options.additional_idl_files = shlex.split(options.additional_idl_files)
+    if len(args) != 1:
+        parser.error('Must specify exactly 1 input file as argument, but %d given.' % len(args))
+    options.idl_filename = os.path.realpath(args[0])
+    return options
+
+
+def main():
+    options = parse_options()
+    idl_filename = options.idl_filename
+    basename = os.path.basename(idl_filename)
+    interface_name, _ = os.path.splitext(basename)
+    verbose = options.verbose
+    if verbose:
+        print idl_filename
+
+    idl_document = read_idl.read_idl_file(idl_filename, verbose=verbose)
+    should_generate_bindings = read_idl.merge_interface_dependencies(idl_document, idl_filename, options.interface_dependencies_file, options.additional_idl_files)
+    if not should_generate_bindings:

[haraken, 2013/07/10 04:06:50]

I'd prefer to write it as follows:

  idl_document = read_idl.read_idl_file(idl_filename,
options.interface_dependencies_file, options.additional_idl_files,
verbose=verbose)
  if not idl_document:
    ...

It seems to me that there is no benefit to expose both read_idl_file and
merge_interface_dependencies to outside of read_idl.py. What people are
interested in would be just a result after the dependency is resolved.

(I'd prefer "parse_idl.parse_idl_file" rather than "read_idl.read_idl_file", but
it's just a bike-shedding.)

[Nils Barth (inactive), 2013/07/10 06:00:15]

<snip>
Yeah, exactly; I've change the interface around as indicated,
which makes it cleaner.

+        # We generate dummy .h and .cpp files just to tell build scripts
+        # that outputs have been created.
+        code_generator_v8.generate_dummy_header_and_cpp(interface_name, options.output_directory)
+        return
+    # FIXME: turn on attribute validator
+    # read_idl.validate_extended_attributes(idl_document, basename, options.idl_attributes_file)
+    # FIXME: turn on code generator
+    # Currently idl_document must be None (so dummy .h and .cpp files are
+    # generated), as actual code generator not present yet.
+    # code_generator_v8.write_interface(idl_document, interface_name, options.output_directory)
+    raise RuntimeError('Stub: code generator not implemented yet')
+
+
+if __name__ == '__main__':
+    sys.exit(main())