bazel/protobuf.bzl

   1 """Utility functions for generating protobuf code."""
   2
   3 _PROTO_EXTENSION = ".proto"
   4
   5 def well_known_proto_libs():
   6     return [
   7         "@com_google_protobuf//:any_proto",
   8         "@com_google_protobuf//:api_proto",
   9         "@com_google_protobuf//:compiler_plugin_proto",
  10         "@com_google_protobuf//:descriptor_proto",
  11         "@com_google_protobuf//:duration_proto",
  12         "@com_google_protobuf//:empty_proto",
  13         "@com_google_protobuf//:field_mask_proto",
  14         "@com_google_protobuf//:source_context_proto",
  15         "@com_google_protobuf//:struct_proto",
  16         "@com_google_protobuf//:timestamp_proto",
  17         "@com_google_protobuf//:type_proto",
  18         "@com_google_protobuf//:wrappers_proto",
  19     ]
  20
  21 def get_proto_root(workspace_root):
  22     """Gets the root protobuf directory.
  23
  24     Args:
  25       workspace_root: context.label.workspace_root
  26
  27     Returns:
  28       The directory relative to which generated include paths should be.
  29     """
  30     if workspace_root:
  31         return "/{}".format(workspace_root)
  32     else:
  33         return ""
  34
  35 def _strip_proto_extension(proto_filename):
  36     if not proto_filename.endswith(_PROTO_EXTENSION):
  37         fail('"{}" does not end with "{}"'.format(
  38             proto_filename,
  39             _PROTO_EXTENSION,
  40         ))
  41     return proto_filename[:-len(_PROTO_EXTENSION)]
  42
  43 def proto_path_to_generated_filename(proto_path, fmt_str):
  44     """Calculates the name of a generated file for a protobuf path.
  45
  46     For example, "examples/protos/helloworld.proto" might map to
  47       "helloworld.pb.h".
  48
  49     Args:
  50       proto_path: The path to the .proto file.
  51       fmt_str: A format string used to calculate the generated filename. For
  52         example, "{}.pb.h" might be used to calculate a C++ header filename.
  53
  54     Returns:
  55       The generated filename.
  56     """
  57     return fmt_str.format(_strip_proto_extension(proto_path))
  58
  59 def _get_include_directory(include):
  60     directory = include.path
  61     prefix_len = 0
  62     if not include.is_source and directory.startswith(include.root.path):
  63         prefix_len = len(include.root.path) + 1
  64
  65     if directory.startswith("external", prefix_len):
  66         external_separator = directory.find("/", prefix_len)
  67         repository_separator = directory.find("/", external_separator + 1)
  68         return directory[:repository_separator]
  69     else:
  70         return include.root.path if include.root.path else "."
  71
  72 def get_include_protoc_args(includes):
  73     """Returns protoc args that imports protos relative to their import root.
  74
  75     Args:
  76       includes: A list of included proto files.
  77
  78     Returns:
  79       A list of arguments to be passed to protoc. For example, ["--proto_path=."].
  80     """
  81     return [
  82         "--proto_path={}".format(_get_include_directory(include))
  83         for include in includes
  84     ]
  85
  86 def get_plugin_args(plugin, flags, dir_out, generate_mocks):
  87     """Returns arguments configuring protoc to use a plugin for a language.
  88
  89     Args:
  90       plugin: An executable file to run as the protoc plugin.
  91       flags: The plugin flags to be passed to protoc.
  92       dir_out: The output directory for the plugin.
  93       generate_mocks: A bool indicating whether to generate mocks.
  94
  95     Returns:
  96       A list of protoc arguments configuring the plugin.
  97     """
  98     augmented_flags = list(flags)
  99     if generate_mocks:
 100         augmented_flags.append("generate_mock_code=true")
 101     return [
 102         "--plugin=protoc-gen-PLUGIN=" + plugin.path,
 103         "--PLUGIN_out=" + ",".join(augmented_flags) + ":" + dir_out,
 104     ]