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_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 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('}')