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# Copyright 2021 The Pigweed 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
#
# https://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.
"""This module generates the code for raw pw_rpc services."""
import os
from typing import Iterable
from pw_protobuf.output_file import OutputFile
from pw_protobuf.proto_tree import ProtoServiceMethod
from pw_protobuf.proto_tree import build_node_tree
from pw_rpc import codegen
from pw_rpc.codegen import (client_call_type, get_id, CodeGenerator,
RPC_NAMESPACE)
PROTO_H_EXTENSION = '.pb.h'
def _proto_filename_to_generated_header(proto_file: str) -> str:
"""Returns the generated C++ RPC header name for a .proto file."""
filename = os.path.splitext(proto_file)[0]
return f'{filename}.raw_rpc{PROTO_H_EXTENSION}'
def _proto_filename_to_stub_header(proto_file: str) -> str:
"""Returns the generated C++ RPC header name for a .proto file."""
filename = os.path.splitext(proto_file)[0]
return f'{filename}.raw_rpc.stub{PROTO_H_EXTENSION}'
def _function(method: ProtoServiceMethod) -> str:
return f'{client_call_type(method, "Raw")} {method.name()}'
def _user_args(method: ProtoServiceMethod) -> Iterable[str]:
if not method.client_streaming():
yield '::pw::ConstByteSpan request'
if method.server_streaming():
yield '::pw::Function<void(::pw::ConstByteSpan)>&& on_next = nullptr'
yield '::pw::Function<void(::pw::Status)>&& on_completed = nullptr'
else:
yield ('::pw::Function<void(::pw::ConstByteSpan, ::pw::Status)>&& '
'on_completed = nullptr')
yield '::pw::Function<void(::pw::Status)>&& on_error = nullptr'
class RawCodeGenerator(CodeGenerator):
"""Generates an RPC service and client using the raw buffers API."""
def name(self) -> str:
return 'raw'
def method_union_name(self) -> str:
return 'RawMethodUnion'
def includes(self, unused_proto_file_name: str) -> Iterable[str]:
yield '#include "pw_rpc/raw/client_reader_writer.h"'
yield '#include "pw_rpc/raw/internal/method_union.h"'
yield '#include "pw_rpc/raw/server_reader_writer.h"'
def service_aliases(self) -> None:
self.line(f'using RawServerWriter = {RPC_NAMESPACE}::RawServerWriter;')
self.line(f'using RawServerReader = {RPC_NAMESPACE}::RawServerReader;')
self.line('using RawServerReaderWriter = '
f'{RPC_NAMESPACE}::RawServerReaderWriter;')
def method_descriptor(self, method: ProtoServiceMethod) -> None:
impl_method = f'&Implementation::{method.name()}'
self.line(f'{RPC_NAMESPACE}::internal::GetRawMethodFor<{impl_method}, '
f'{method.type().cc_enum()}>(')
self.line(f' {get_id(method)}), // Hash of "{method.name()}"')
def client_member_function(self, method: ProtoServiceMethod) -> None:
self.line(f'{_function(method)}(')
self.indented_list(*_user_args(method), end=') const {')
with self.indent():
base = 'Stream' if method.server_streaming() else 'Unary'
self.line(f'return {RPC_NAMESPACE}::internal::'
f'{base}ResponseClientCall::'
f'Start<{client_call_type(method, "Raw")}>(')
service_client = RPC_NAMESPACE + '::internal::ServiceClient'
arg = ['std::move(on_next)'] if method.server_streaming() else []
self.indented_list(
f'{service_client}::client()',
f'{service_client}::channel_id()',
'kServiceId',
get_id(method),
*arg,
'std::move(on_completed)',
'std::move(on_error)',
'{}' if method.client_streaming() else 'request',
end=');')
self.line('}')
def client_static_function(self, method: ProtoServiceMethod) -> None:
self.line(f'static {_function(method)}(')
self.indented_list(f'{RPC_NAMESPACE}::Client& client',
'uint32_t channel_id',
*_user_args(method),
end=') {')
with self.indent():
self.line(f'return Client(client, channel_id).{method.name()}(')
args = []
if not method.client_streaming():
args.append('request')
if method.server_streaming():
args.append('std::move(on_next)')
self.indented_list(*args,
'std::move(on_completed)',
'std::move(on_error)',
end=');')
self.line('}')
def method_info_specialization(self, method: ProtoServiceMethod) -> None:
self.line()
# We have Request/Response as voids to mark raw as a special case.
# Raw operates in ConstByteSpans, which won't be copied by copying the
# span itself and without special treatment will lead to dangling
# pointers.
#
# Helpers/traits that want to use Request/Response and should support
# raw are required to do a special implementation for them instead that
# will copy the actual data.
self.line('using Request = void;')
self.line('using Response = void;')
class StubGenerator(codegen.StubGenerator):
def unary_signature(self, method: ProtoServiceMethod, prefix: str) -> str:
return (f'void {prefix}{method.name()}(pw::ConstByteSpan request, '
'pw::rpc::RawUnaryResponder& responder)')
def unary_stub(self, method: ProtoServiceMethod,
output: OutputFile) -> None:
output.write_line(codegen.STUB_REQUEST_TODO)
output.write_line('static_cast<void>(request);')
output.write_line(codegen.STUB_RESPONSE_TODO)
output.write_line('static_cast<void>(responder);')
def server_streaming_signature(self, method: ProtoServiceMethod,
prefix: str) -> str:
return (f'void {prefix}{method.name()}('
'pw::ConstByteSpan request, RawServerWriter& writer)')
def client_streaming_signature(self, method: ProtoServiceMethod,
prefix: str) -> str:
return f'void {prefix}{method.name()}(RawServerReader& reader)'
def bidirectional_streaming_signature(self, method: ProtoServiceMethod,
prefix: str) -> str:
return (f'void {prefix}{method.name()}('
'RawServerReaderWriter& reader_writer)')
def process_proto_file(proto_file) -> Iterable[OutputFile]:
"""Generates code for a single .proto file."""
_, package_root = build_node_tree(proto_file)
output_filename = _proto_filename_to_generated_header(proto_file.name)
generator = RawCodeGenerator(output_filename)
codegen.generate_package(proto_file, package_root, generator)
codegen.package_stubs(package_root, generator, StubGenerator())
return [generator.output]