Bindings build: split compute_interfaces_info into 2 stages

Source/bindings/scripts/compute_interfaces_info.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.
-
-"""Compute global interface information, including public information, dependencies, and inheritance.
-
-Computed data is stored in a global variable, |interfaces_info|, and written as
-output (concretely, exported as a pickle). This is then used by the IDL compiler
-itself, so it does not need to compute global information itself, and so that
-inter-IDL dependencies are clear, since they are all computed here.
-
-The |interfaces_info| pickle is a *global* dependency: any changes cause a full
-rebuild. This is to avoid having to compute which public data is visible by
-which IDL files on a file-by-file basis, which is very complex for little
-benefit.
-|interfaces_info| should thus only contain data about an interface that
-contains paths or is needed by *other* interfaces, e.g., path data (to abstract
-the compiler from OS-specific file paths) or public data (to avoid having to
-read other interfaces unnecessarily).
-It should *not* contain full information about an interface (e.g., all
-extended attributes), as this would cause unnecessary rebuilds.
-
-|interfaces_info| is a dict, keyed by |interface_name|.
-
-Current keys are:
-* dependencies:
-    'implements_interfaces': targets of 'implements' statements
-    'referenced_interfaces': reference interfaces that are introspected
-                             (currently just targets of [PutForwards])
-
-* inheritance:
-    'ancestors': all ancestor interfaces
-    'inherited_extended_attributes': inherited extended attributes
-                                     (all controlling memory management)
-
-* public:
-    'is_callback_interface': bool, callback interface or not
-    'implemented_as': value of [ImplementedAs=...] on interface (C++ class name)
-
-* paths:
-    'full_path': path to the IDL file, so can lookup an IDL by interface name
-    'include_path': path for use in C++ #include directives
-    'dependencies_full_paths': paths to dependencies (for merging into main)
-    'dependencies_include_paths': paths for use in C++ #include directives
-
-Note that all of these are stable information, unlikely to change without
-moving or deleting files (hence requiring a full rebuild anyway) or significant
-code changes (for inherited extended attributes).
-
-Design doc: http://www.chromium.org/developers/design-documents/idl-build
-"""
-
-from collections import defaultdict
-import optparse
-import os
-import posixpath
-import sys
-
-from utilities import get_file_contents, write_pickle_file, get_interface_extended_attributes_from_idl, is_callback_interface_from_idl, get_partial_interface_name_from_idl, get_implements_from_idl, get_parent_interface, get_put_forward_interfaces_from_idl
-
-module_path = os.path.dirname(__file__)
-source_path = os.path.normpath(os.path.join(module_path, os.pardir, os.pardir))
-
-INHERITED_EXTENDED_ATTRIBUTES = set([
-    'ActiveDOMObject',
-    'DependentLifetime',
-    'GarbageCollected',
-    'WillBeGarbageCollected',
-])
-
-# Main variable (filled in and exported)
-interfaces_info = {}
-
-# Auxiliary variables (not visible to future build steps)
-partial_interface_files = defaultdict(lambda: {
-    'full_paths': [],
-    'include_paths': [],
-})
-parent_interfaces = {}
-inherited_extended_attributes_by_interface = {}  # interface name -> extended attributes
-
-
-class IdlInterfaceFileNotFoundError(Exception):
-    """Raised if the IDL file implementing an interface cannot be found."""
-    pass
-
-
-def parse_options():
-    usage = 'Usage: %prog [options] [generated1.idl]...'
-    parser = optparse.OptionParser(usage=usage)
-    parser.add_option('--idl-files-list', help='file listing IDL files')
-    parser.add_option('--interfaces-info-file', help='output pickle file')
-    parser.add_option('--write-file-only-if-changed', type='int', help='if true, do not write an output file if it would be identical to the existing one, which avoids unnecessary rebuilds in ninja')
-
-    options, args = parser.parse_args()
-    if options.interfaces_info_file is None:
-        parser.error('Must specify an output file using --interfaces-info-file.')
-    if options.idl_files_list is None:
-        parser.error('Must specify a file listing IDL files using --idl-files-list.')
-    if options.write_file_only_if_changed is None:
-        parser.error('Must specify whether file is only written if changed using --write-file-only-if-changed.')
-    options.write_file_only_if_changed = bool(options.write_file_only_if_changed)
-    return options, args
-
-
-################################################################################
-# Computations
-################################################################################
-
-def include_path(idl_filename, implemented_as=None):
-    """Returns relative path to header file in POSIX format; used in includes.
-
-    POSIX format is used for consistency of output, so reference tests are
-    platform-independent.
-    """
-    relative_path_local = os.path.relpath(idl_filename, source_path)
-    relative_dir_local = os.path.dirname(relative_path_local)
-    relative_dir_posix = relative_dir_local.replace(os.path.sep, posixpath.sep)
-
-    idl_file_basename, _ = os.path.splitext(os.path.basename(idl_filename))
-    cpp_class_name = implemented_as or idl_file_basename
-
-    return posixpath.join(relative_dir_posix, cpp_class_name + '.h')
-
-
-def add_paths_to_partials_dict(partial_interface_name, full_path, this_include_path=None):
-    paths_dict = partial_interface_files[partial_interface_name]
-    paths_dict['full_paths'].append(full_path)
-    if this_include_path:
-        paths_dict['include_paths'].append(this_include_path)
-
-
-def compute_individual_info(idl_filename):
-    full_path = os.path.realpath(idl_filename)
-    idl_file_contents = get_file_contents(full_path)
-
-    extended_attributes = get_interface_extended_attributes_from_idl(idl_file_contents)
-    implemented_as = extended_attributes.get('ImplementedAs')
-    this_include_path = include_path(idl_filename, implemented_as)
-
-    # Handle partial interfaces
-    partial_interface_name = get_partial_interface_name_from_idl(idl_file_contents)
-    if partial_interface_name:
-        add_paths_to_partials_dict(partial_interface_name, full_path, this_include_path)
-        return
-
-    # If not a partial interface, the basename is the interface name
-    interface_name, _ = os.path.splitext(os.path.basename(idl_filename))
-
-    # 'implements' statements can be included in either the file for the
-    # implement*ing* interface (lhs of 'implements') or implement*ed* interface
-    # (rhs of 'implements'). Store both for now, then merge to implement*ing*
-    # interface later.
-    left_interfaces, right_interfaces = get_implements_from_idl(idl_file_contents, interface_name)
-
-    interfaces_info[interface_name] = {
-        'full_path': full_path,
-        'implemented_as': implemented_as,
-        'implemented_by_interfaces': left_interfaces,  # private, merged to next
-        'implements_interfaces': right_interfaces,
-        'include_path': this_include_path,
-        # FIXME: temporary private field, while removing old treatement of
-        # 'implements': http://crbug.com/360435
-        'is_legacy_treat_as_partial_interface': 'LegacyTreatAsPartialInterface' in extended_attributes,
-        'is_callback_interface': is_callback_interface_from_idl(idl_file_contents),
-        # Interfaces that are referenced (used as types) and that we introspect
-        # during code generation (beyond interface-level data ([ImplementedAs],
-        # is_callback_interface, ancestors, and inherited extended attributes):
-        # deep dependencies.
-        # These cause rebuilds of referrers, due to the dependency, so these
-        # should be minimized; currently only targets of [PutForwards].
-        'referenced_interfaces': get_put_forward_interfaces_from_idl(idl_file_contents),
-    }
-
-    # Record inheritance information
-    inherited_extended_attributes_by_interface[interface_name] = dict(
-            (key, value)
-            for key, value in extended_attributes.iteritems()
-            if key in INHERITED_EXTENDED_ATTRIBUTES)
-    parent = get_parent_interface(idl_file_contents)
-    if parent:
-        parent_interfaces[interface_name] = parent
-
-
-def compute_inheritance_info(interface_name):
-    """Compute inheritance information, namely ancestors and inherited extended attributes."""
-    def generate_ancestors(interface_name):
-        while interface_name in parent_interfaces:
-            interface_name = parent_interfaces[interface_name]
-            yield interface_name
-
-    ancestors = list(generate_ancestors(interface_name))
-    inherited_extended_attributes = inherited_extended_attributes_by_interface[interface_name]
-    for ancestor in ancestors:
-        # Ancestors may not be present, notably if an ancestor is a generated
-        # IDL file and we are running this script from run-bindings-tests,
-        # where we don't generate these files.
-        ancestor_extended_attributes = inherited_extended_attributes_by_interface.get(ancestor, {})
-        inherited_extended_attributes.update(ancestor_extended_attributes)
-
-    interfaces_info[interface_name].update({
-        'ancestors': ancestors,
-        'inherited_extended_attributes': inherited_extended_attributes,
-    })
-
-
-def compute_interfaces_info(idl_files):
-    """Compute information about IDL files.
-
-    Information is stored in global interfaces_info.
-    """
-    # Compute information for individual files
-    for idl_filename in idl_files:
-        compute_individual_info(idl_filename)
-
-    # Once all individual files handled, can compute inheritance information
-    # and dependencies
-
-    # Compute inheritance info
-    for interface_name in interfaces_info:
-        compute_inheritance_info(interface_name)
-
-    # Compute dependencies
-    # Move implements info from implement*ed* interface (rhs of 'implements')
-    # to implement*ing* interface (lhs of 'implements').
-    # Note that moving an 'implements' statement between implementing and
-    # implemented files does not change the info (or hence cause a rebuild)!
-    for right_interface_name, interface_info in interfaces_info.iteritems():
-        for left_interface_name in interface_info['implemented_by_interfaces']:
-            interfaces_info[left_interface_name]['implements_interfaces'].append(right_interface_name)
-        del interface_info['implemented_by_interfaces']
-
-    # An IDL file's dependencies are partial interface files that extend it,
-    # and files for other interfaces that this interfaces implements.
-    for interface_name, interface_info in interfaces_info.iteritems():
-        partial_interface_paths = partial_interface_files[interface_name]
-        partial_interfaces_full_paths = partial_interface_paths['full_paths']
-        # Partial interface definitions each need an include, as they are
-        # implemented in separate classes from the main interface.
-        partial_interfaces_include_paths = partial_interface_paths['include_paths']
-
-        implemented_interfaces = interface_info['implements_interfaces']
-        try:
-            implemented_interfaces_info = [
-                interfaces_info[interface]
-                for interface in implemented_interfaces]
-        except KeyError as key_name:
-            raise IdlInterfaceFileNotFoundError('Could not find the IDL file where the following implemented interface is defined: %s' % key_name)
-        implemented_interfaces_full_paths = [
-            implemented_interface_info['full_path']
-            for implemented_interface_info in implemented_interfaces_info]
-        # Implemented interfaces don't need includes, as this is handled in
-        # the Blink implementation (they are implemented on |impl| itself,
-        # hence header is included in implementing class).
-        # However, they are needed for legacy implemented interfaces that
-        # are being treated as partial interfaces, until we remove these.
-        # http://crbug.com/360435
-        implemented_interfaces_include_paths = [
-            implemented_interface_info['include_path']
-            for implemented_interface_info in implemented_interfaces_info
-            if implemented_interface_info['is_legacy_treat_as_partial_interface']]
-
-        interface_info.update({
-            'dependencies_full_paths': (partial_interfaces_full_paths +
-                                        implemented_interfaces_full_paths),
-            'dependencies_include_paths': (partial_interfaces_include_paths +
-                                           implemented_interfaces_include_paths),
-        })
-
-    # Clean up temporary private information
-    for interface_info in interfaces_info.itervalues():
-        del interface_info['is_legacy_treat_as_partial_interface']
-
-
-################################################################################
-
-def main():
-    options, args = parse_options()
-
-    # Static IDL files are passed in a file (generated at GYP time), due to OS
-    # command line length limits
-    with open(options.idl_files_list) as idl_files_list:
-        idl_files = [line.rstrip('\n') for line in idl_files_list]
-    # Generated IDL files are passed at the command line, since these are in the
-    # build directory, which is determined at build time, not GYP time, so these
-    # cannot be included in the file listing static files
-    idl_files.extend(args)
-
-    compute_interfaces_info(idl_files)
-    write_pickle_file(options.interfaces_info_file,
-                      interfaces_info,
-                      options.write_file_only_if_changed)
-
-
-if __name__ == '__main__':
-    sys.exit(main())