blob: 8deec5d1949856b34889b9e3f9085a479769cf10 [file] [log] [blame]
#!/usr/bin/env python3
# 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
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# 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
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
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."""
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'
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.
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(
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
# Filter lines that are pure comments. line_comment_prefix is not enough because it removes
# the comment but doesn't completely remove the line, resulting in more verbose output.
lines = filter(lambda line: not line.strip().startswith('//*'), lines)
# Remove indentation templates have for the Jinja control flow.
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:]
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):
base_params = {
'enumerate': enumerate,
'format': format,
'len': len,
'debug': debug,
'assert': do_assert,
outputs = []
for render in renders:
params = {}
for param_dict in render.params_dicts:
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):
if (path.endswith('.pyc')
or (path.endswith('c') and not os.path.splitext(path)[1])):
path = path[:-1]
return paths
def run_generator(generator):
parser = argparse.ArgumentParser(
description = generator.get_description(),
formatter_class = argparse.ArgumentDefaultsHelpFormatter,
parser.add_argument('--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.")
parser.add_argument('--print-cmake-dependencies', default=False, action="store_true", help="Prints a semi-colon separated list of dependencies to stdout and exits.")
parser.add_argument('--print-cmake-outputs', default=False, action="store_true", help="Prints a semi-colon separated list of outputs to stdout and exits.")
parser.add_argument('--output-dir', default=None, type=str, help='Directory where to output generate files.')
args = parser.parse_args()
renders = generator.get_file_renders(args);
# Output a list of all dependencies for CMake or the tarball for GN/Ninja.
if args.depfile != None or args.print_cmake_dependencies:
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)
if args.depfile != None:
with open(args.depfile, 'w') as f:
f.write(args.output_json_tarball + ": " + " ".join(dependencies))
if args.print_cmake_dependencies:
return 0
# 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
# Print the list of all the outputs for cmake.
if args.print_cmake_outputs:
sys.stdout.write(";".join([os.path.join(args.output_dir, render.output) for render in renders]))
return 0
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 JSON tarball
if args.output_json_tarball != None:
json_root = {}
for output in outputs:
json_root[] = output.content
with open(args.output_json_tarball, 'w') as f:
# Output the files directly.
if args.output_dir != None:
for output in outputs:
output_path = os.path.join(args.output_dir,
directory = os.path.dirname(output_path)
if not os.path.exists(directory):
with open(output_path, 'w') as outfile: