dawn-cmake/generator/generator_lib.py
Corentin Wallez 05623df97f BUILD.gn: Add a check generated files are in allowed dirs.
This is important so that we know that the list of allowed directories
is in sync with other parts of the build in follow-up commits.

BUG=dawn:22

Change-Id: I202bec55b510989e43acf497956e2937c9a2f60a
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/11360
Reviewed-by: Austin Eng <enga@chromium.org>
Reviewed-by: Kai Ninomiya <kainino@chromium.org>
Commit-Queue: Corentin Wallez <cwallez@chromium.org>
2019-09-18 23:19:31 +00:00

272 lines
10 KiB
Python

#!/usr/bin/env python2
# Copyright 2019 The Dawn Authors
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
"""Module to create generators that render multiple Jinja2 templates for GN.
A helper module that can be used to create generator scripts (clients)
that expand one or more Jinja2 templates, without outputs usable from
GN and Ninja build-based systems. See generator_lib.gni as well.
Clients should create a Generator sub-class, then call run_generator()
with a proper derived class instance.
Clients specify a list of FileRender operations, each one of them will
output a file into a temporary output directory through Jinja2 expansion.
All temporary output files are then grouped and written to into a single JSON
file, that acts as a convenient single GN output target. Use extract_json.py
to extract the output files from the JSON tarball in another GN action.
--depfile can be used to specify an output Ninja dependency file for the
JSON tarball, to ensure it is regenerated any time one of its dependencies
changes.
Finally, --expected-output-files can be used to check the list of generated
output files.
"""
import argparse, json, os, re, sys
from collections import namedtuple
# A FileRender represents a single Jinja2 template render operation:
#
# template: Jinja2 template name, relative to --template-dir path.
#
# output: Output file path, relative to temporary output directory.
#
# params_dicts: iterable of (name:string -> value:string) dictionaries.
# All of them will be merged before being sent as Jinja2 template
# expansion parameters.
#
# Example:
# FileRender('api.c', 'src/project_api.c', [{'PROJECT_VERSION': '1.0.0'}])
#
FileRender = namedtuple('FileRender', ['template', 'output', 'params_dicts'])
# The interface that must be implemented by generators.
class Generator:
def get_description(self):
"""Return generator description for --help."""
return ""
def add_commandline_arguments(self, parser):
"""Add generator-specific argparse arguments."""
pass
def get_file_renders(self, args):
"""Return the list of FileRender objects to process."""
return []
def get_dependencies(self, args):
"""Return a list of extra input dependencies."""
return []
# Allow custom Jinja2 installation path through an additional python
# path from the arguments if present. This isn't done through the regular
# argparse because PreprocessingLoader uses jinja2 in the global scope before
# "main" gets to run.
#
# NOTE: If this argument appears several times, this only uses the first
# value, while argparse would typically keep the last one!
kJinja2Path = '--jinja2-path'
try:
jinja2_path_argv_index = sys.argv.index(kJinja2Path)
# Add parent path for the import to succeed.
path = os.path.join(sys.argv[jinja2_path_argv_index + 1], os.pardir)
sys.path.insert(1, path)
except ValueError:
# --jinja2-path isn't passed, ignore the exception and just import Jinja2
# assuming it already is in the Python PATH.
pass
import jinja2
# A custom Jinja2 template loader that removes the extra indentation
# of the template blocks so that the output is correctly indented
class _PreprocessingLoader(jinja2.BaseLoader):
def __init__(self, path):
self.path = path
def get_source(self, environment, template):
path = os.path.join(self.path, template)
if not os.path.exists(path):
raise jinja2.TemplateNotFound(template)
mtime = os.path.getmtime(path)
with open(path) as f:
source = self.preprocess(f.read())
return source, path, lambda: mtime == os.path.getmtime(path)
blockstart = re.compile('{%-?\s*(if|elif|else|for|block|macro)[^}]*%}')
blockend = re.compile('{%-?\s*(end(if|for|block|macro)|elif|else)[^}]*%}')
def preprocess(self, source):
lines = source.split('\n')
# Compute the current indentation level of the template blocks and remove their indentation
result = []
indentation_level = 0
for line in lines:
# The capture in the regex adds one element per block start or end so we divide by two
# there is also an extra line chunk corresponding to the line end, so we substract it.
numends = (len(self.blockend.split(line)) - 1) // 2
indentation_level -= numends
result.append(self.remove_indentation(line, indentation_level))
numstarts = (len(self.blockstart.split(line)) - 1) // 2
indentation_level += numstarts
return '\n'.join(result) + '\n'
def remove_indentation(self, line, n):
for _ in range(n):
if line.startswith(' '):
line = line[4:]
elif line.startswith('\t'):
line = line[1:]
else:
assert(line.strip() == '')
return line
_FileOutput = namedtuple('FileOutput', ['name', 'content'])
def _do_renders(renders, template_dir):
loader = _PreprocessingLoader(template_dir)
env = jinja2.Environment(loader=loader, lstrip_blocks=True, trim_blocks=True, line_comment_prefix='//*')
def do_assert(expr):
assert expr
return ''
def debug(text):
print(text)
base_params = {
'enumerate': enumerate,
'format': format,
'len': len,
'debug': debug,
'assert': do_assert,
}
outputs = []
for render in renders:
params = {}
params.update(base_params)
for param_dict in render.params_dicts:
params.update(param_dict)
content = env.get_template(render.template).render(**params)
outputs.append(_FileOutput(render.output, content))
return outputs
# Compute the list of imported, non-system Python modules.
# It assumes that any path outside of the root directory is system.
def _compute_python_dependencies(root_dir = None):
if not root_dir:
# Assume this script is under generator/ by default.
root_dir = os.path.join(os.path.dirname(__file__), os.pardir)
root_dir = os.path.abspath(root_dir)
module_paths = (module.__file__ for module in sys.modules.values()
if module and hasattr(module, '__file__'))
paths = set()
for path in module_paths:
path = os.path.abspath(path)
if not path.startswith(root_dir):
continue
if (path.endswith('.pyc')
or (path.endswith('c') and not os.path.splitext(path)[1])):
path = path[:-1]
paths.add(path)
return paths
def run_generator(generator):
parser = argparse.ArgumentParser(
description = generator.get_description(),
formatter_class = argparse.ArgumentDefaultsHelpFormatter
)
generator.add_commandline_arguments(parser);
parser.add_argument('-t', '--template-dir', default='templates', type=str, help='Directory with template files.')
parser.add_argument(kJinja2Path, default=None, type=str, help='Additional python path to set before loading Jinja2')
parser.add_argument('--output-json-tarball', default=None, type=str, help='Name of the "JSON tarball" to create (tar is too annoying to use in python).')
parser.add_argument('--depfile', default=None, type=str, help='Name of the Ninja depfile to create for the JSON tarball')
parser.add_argument('--expected-outputs-file', default=None, type=str, help="File to compare outputs with and fail if it doesn't match")
parser.add_argument('--root-dir', default=None, type=str, help='Optional source root directory for Python dependency computations')
parser.add_argument('--allowed-output-dirs-file', default=None, type=str, help="File containing a list of allowed directories where files can be output.")
args = parser.parse_args()
renders = generator.get_file_renders(args);
# The caller wants to assert that the outputs are what it expects.
# Load the file and compare with our renders.
if args.expected_outputs_file != None:
with open(args.expected_outputs_file) as f:
expected = set([line.strip() for line in f.readlines()])
actual = {render.output for render in renders}
if actual != expected:
print("Wrong expected outputs, caller expected:\n " + repr(sorted(expected)))
print("Actual output:\n " + repr(sorted(actual)))
return 1
outputs = _do_renders(renders, args.template_dir)
# The caller wants to assert that the outputs are only in specific directories.
if args.allowed_output_dirs_file != None:
with open(args.allowed_output_dirs_file) as f:
allowed_dirs = set([line.strip() for line in f.readlines()])
for directory in allowed_dirs:
if not directory.endswith('/'):
print('Allowed directory entry "{}" doesn\'t end with /'.format(directory))
return 1
def check_in_subdirectory(path, directory):
return path.startswith(directory) and not '/' in path[len(directory):]
for render in renders:
if not any(check_in_subdirectory(render.output, directory) for directory in allowed_dirs):
print('Output file "{}" is not in the allowed directory list below:'.format(render.output))
for directory in sorted(allowed_dirs):
print(' "{}"'.format(directory))
return 1
# Output the tarball and its depfile
if args.output_json_tarball != None:
json_root = {}
for output in outputs:
json_root[output.name] = output.content
with open(args.output_json_tarball, 'w') as f:
f.write(json.dumps(json_root))
# Output a list of all dependencies for the tarball for Ninja.
if args.depfile != None:
dependencies = generator.get_dependencies(args)
dependencies += [args.template_dir + os.path.sep + render.template for render in renders]
dependencies += _compute_python_dependencies(args.root_dir)
with open(args.depfile, 'w') as f:
f.write(args.output_json_tarball + ": " + " ".join(dependencies))