| # Copyright 2019 The LUCI 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. |
| |
| """API for reading files.""" |
| |
| def _read_file(path): |
| """Reads a file and returns its contents as a string. |
| |
| Useful for rules that accept large chunks of free form text. By using |
| `io.read_file` such text can be kept in a separate file. |
| |
| Args: |
| path: either a path relative to the currently executing Starlark script, |
| or (if starts with `//`) an absolute path within the currently executing |
| package. If it is a relative path, it must point somewhere inside the |
| current package directory. Required. |
| |
| Returns: |
| The contents of the file as a string. Fails if there's no such file, it |
| can't be read, or it is outside of the current package directory. |
| """ |
| return __native__.read_file(path) |
| |
| def _read_proto(ctor, path, encoding = None): |
| """Reads a serialized proto message from a file, deserializes and returns it. |
| |
| Args: |
| ctor: a constructor function that defines the message type. Required. |
| path: either a path relative to the currently executing Starlark script, |
| or (if starts with `//`) an absolute path within the currently executing |
| package. If it is a relative path, it must point somewhere inside the |
| current package directory. Required. |
| encoding: either `jsonpb` or `textpb` or `auto` to detect based on the |
| file extension. Default is `auto`. |
| |
| Returns: |
| Deserialized proto message constructed via `ctor`. |
| """ |
| if encoding == None or encoding == "auto": |
| ext = path[path.rfind(".") + 1:].lower() |
| encoding = "jsonpb" if ext in ["json", "jsonpb"] else "textpb" |
| if encoding == "jsonpb": |
| return proto.from_jsonpb(ctor, _read_file(path)) |
| if encoding == "textpb": |
| return proto.from_textpb(ctor, _read_file(path)) |
| fail("unknown proto encoding %r" % (encoding,)) |
| |
| io = struct( |
| read_file = _read_file, |
| read_proto = _read_proto, |
| ) |