def forward_declare(
node: ProtoNode,
root: ProtoNode,
output: OutputFile,
) -> None:
"""Generates code forward-declaring entities in a message's namespace."""
if node.type() != ProtoNode.Type.MESSAGE:
return
namespace = node.cpp_namespace(root)
output.write_line()
output.write_line(f'namespace {namespace} {{')
# Define an enum defining each of the message's fields and their numbers.
output.write_line('enum class Fields {')
with output.indent():
for field in node.fields():
output.write_line(f'{field.enum_name()} = {field.number()},')
output.write_line('};')
# Declare the message's encoder class and all of its enums.
output.write_line()
output.write_line('class Encoder;')
for child in node.children():
if child.type() == ProtoNode.Type.ENUM:
output.write_line()
generate_code_for_enum(child, node, output)
output.write_line(f'}} // namespace {namespace}')
def generate_code_for_enum(enum: ProtoNode, root: ProtoNode,
output: OutputFile) -> None:
"""Creates a C++ enum for a proto enum."""
assert enum.type() == ProtoNode.Type.ENUM
output.write_line(f'enum class {enum.cpp_namespace(root)} {{')
with output.indent():
for name, number in enum.values():
output.write_line(f'{name} = {number},')
output.write_line('};')
def generate_code_for_package(file_descriptor_proto, package: ProtoNode,
output: OutputFile) -> None:
"""Generates code for a single .pb.h file corresponding to a .proto file."""
assert package.type() == ProtoNode.Type.PACKAGE
output.write_line(f'// {os.path.basename(output.name())} automatically '
f'generated by {PLUGIN_NAME} {PLUGIN_VERSION}')
output.write_line('#pragma once\n')
output.write_line('#include <cstddef>')
output.write_line('#include <cstdint>\n')
output.write_line('#include "pw_protobuf/codegen.h"')
for imported_file in file_descriptor_proto.dependency:
generated_header = _proto_filename_to_generated_header(imported_file)
output.write_line(f'#include "{generated_header}"')
if package.cpp_namespace():
file_namespace = package.cpp_namespace()
if file_namespace.startswith('::'):
file_namespace = file_namespace[2:]
output.write_line(f'\nnamespace {file_namespace} {{')
for node in package:
forward_declare(node, package, output)
# Define all top-level enums.
for node in package.children():
if node.type() == ProtoNode.Type.ENUM:
output.write_line()
generate_code_for_enum(node, package, output)
# Run through all messages in the file, generating a class for each.
for node in package:
if node.type() == ProtoNode.Type.MESSAGE:
output.write_line()
generate_code_for_message(node, package, output)
# Run a second pass through the classes, this time defining all of the
# methods which were previously only declared.
for node in package:
if node.type() == ProtoNode.Type.MESSAGE:
define_not_in_class_methods(node, package, output)
if package.cpp_namespace():
output.write_line(f'\n}} // namespace {package.cpp_namespace()}')
def generate_code_for_message(
message: ProtoNode,
root: ProtoNode,
output: OutputFile,
) -> None:
"""Creates a C++ class for a protobuf message."""
assert message.type() == ProtoNode.Type.MESSAGE
# Message classes inherit from the base proto message class in codegen.h
# and use its constructor.
base_class = f'{PROTOBUF_NAMESPACE}::{BASE_PROTO_CLASS}'
output.write_line(
f'class {message.cpp_namespace(root)}::Encoder : public {base_class} {{'
)
output.write_line(' public:')
with output.indent():
output.write_line(f'using {BASE_PROTO_CLASS}::{BASE_PROTO_CLASS};')
# Generate methods for each of the message's fields.
for field in message.fields():
for method_class in PROTO_FIELD_METHODS[field.type()]:
method = method_class(field, message, root)
if not method.should_appear():
continue
output.write_line()
method_signature = (
f'{method.return_type()} '
f'{method.name()}({method.param_string()})')
if not method.in_class_definition():
# Method will be defined outside of the class at the end of
# the file.
output.write_line(f'{method_signature};')
continue
output.write_line(f'{method_signature} {{')
with output.indent():
for line in method.body():
output.write_line(line)
output.write_line('}')
output.write_line('};')
def add_message_fields(
root: ProtoNode,
message: ProtoNode,
proto_message,
) -> None:
"""Adds fields from a protobuf message descriptor to a message node."""
assert message.type() == ProtoNode.Type.MESSAGE
for field in proto_message.field:
if field.type_name:
# The "type_name" member contains the global .proto path of the
# field's type object, for example ".pw.protobuf.test.KeyValuePair".
# Since only a single proto file is currently supported, the root
# node has the value of the file's package ("pw.protobuf.test").
# This must be stripped from the path to find the desired node
# within the tree.
#
# TODO(frolv): Once multiple files are supported, the root node
# should refer to the global namespace, and this should no longer
# be needed.
path = field.type_name
if path[0] == '.':
path = path[1:]
if path.startswith(root.name()):
relative_path = path[len(root.name()):].lstrip('.')
else:
relative_path = path
type_node = root.find(relative_path)
else:
type_node = None
repeated = \
field.label == descriptor_pb2.FieldDescriptorProto.LABEL_REPEATED
message.add_field(
ProtoMessageField(
field.name,
field.number,
field.type,
type_node,
repeated,
))
def define_not_in_class_methods(message: ProtoNode, root: ProtoNode,
output: OutputFile) -> None:
"""Defines methods for a message class that were previously declared."""
assert message.type() == ProtoNode.Type.MESSAGE
for field in message.fields():
for method_class in PROTO_FIELD_METHODS[field.type()]:
method = method_class(field, message, root)
if not method.should_appear() or method.in_class_definition():
continue
output.write_line()
class_name = f'{message.cpp_namespace(root)}::Encoder'
method_signature = (
f'inline {method.return_type(from_root=True)} '
f'{class_name}::{method.name()}({method.param_string()})')
output.write_line(f'{method_signature} {{')
with output.indent():
for line in method.body():
output.write_line(line)
output.write_line('}')
def add_message_fields(global_root: ProtoNode, package_root: ProtoNode,
message: ProtoNode, proto_message) -> None:
"""Adds fields from a protobuf message descriptor to a message node."""
assert message.type() == ProtoNode.Type.MESSAGE
for field in proto_message.field:
if field.type_name:
# The "type_name" member contains the global .proto path of the
# field's type object, for example ".pw.protobuf.test.KeyValuePair".
# Try to find the node for this object within the current context.
if field.type_name[0] == '.':
# Fully qualified path.
root_relative_path = field.type_name[1:]
search_root = global_root
else:
root_relative_path = field.type_name
search_root = package_root
type_node = search_root.find(root_relative_path)
if type_node is None:
# Create nodes for field types that don't exist within this
# compilation context, such as those imported from other .proto
# files.
type_node = create_external_nodes(search_root,
root_relative_path)
else:
type_node = None
repeated = \
field.label == descriptor_pb2.FieldDescriptorProto.LABEL_REPEATED
message.add_field(
ProtoMessageField(
field.name,
field.number,
field.type,
type_node,
repeated,
))
def add_enum_fields(enum: ProtoNode, proto_enum) -> None:
"""Adds fields from a protobuf enum descriptor to an enum node."""
assert enum.type() == ProtoNode.Type.ENUM
for value in proto_enum.value:
enum.add_value(value.name, value.number)
