commit bcaf883773fc10ac614b60593ab565b1a721e7fb
author Wyatt Hepler <hepler@google.com> Tue May 25 11:20:04 2021 -0700
committer CQ Bot Account <pigweed-scoped@luci-project-accounts.iam.gserviceaccount.com> Wed May 26 16:08:42 2021 +0000
tree 2d8fe6f1f097b1d1e9c5e1df98768b70c02c2d8a
parent e22ac20e5e7dc65a5ddf5b9397f6407957683de7

pw_protobuf_compiler: Handle deps on nanopb.proto

- Add a pw_proto_library for nanopb.proto to the CMake build.
- Skip recompiling nanopb.proto when running protoc for Nanopb.
- Add the pw_protobuf_compiler Nanopb test to CMake.

Change-Id: I3469f35524b18efd3d484b17609e9de0f160e73a
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/46961
Pigweed-Auto-Submit: Wyatt Hepler <hepler@google.com>
Reviewed-by: Alexei Frolov <frolv@google.com>
Commit-Queue: Wyatt Hepler <hepler@google.com>

pw_protobuf_compiler/proto.cmake

diff --git a/pw_protobuf_compiler/proto.cmake b/pw_protobuf_compiler/proto.cmake
index b7a4643..b7a466b 100644
--- a/pw_protobuf_compiler/proto.cmake
+++ b/pw_protobuf_compiler/proto.cmake
@@ -33,7 +33,7 @@
 #   PREFIX - prefix add to the proto files
 #   STRIP_PREFIX - prefix to remove from the proto files
 #   INPUTS - files to include along with the .proto files (such as Nanopb
-#       .options files
+#       .options files)
 #
 function(pw_proto_library NAME)
   cmake_parse_arguments(PARSE_ARGV 1 arg "" "STRIP_PREFIX;PREFIX"
@@ -236,28 +236,37 @@
     )
     set(generated_outputs $<TARGET_PROPERTY:pw_build.empty,SOURCES>)
   else()
-    _pw_generate_protos("${NAME}._generate.nanopb"
-        nanopb
-        "${dir_pw_third_party_nanopb}/generator/protoc-gen-nanopb"
-        ".pb.h;.pb.c"
-        "${INCLUDE_FILE}"
-        "${OUT_DIR}"
-        "${SOURCES}"
-        "${INPUTS}"
-        "${DEPS}"
-    )
+    # When compiling with the Nanopb plugin, the nanopb.proto file is already
+    # compiled internally, so skip recompiling it with protoc.
+    if("${SOURCES}" MATCHES "nanopb\\.proto")
+      add_custom_target("${NAME}._generate.nanopb")  # Nothing to do
+      add_library("${NAME}.nanopb" INTERFACE)
+      target_link_libraries("${NAME}.nanopb" INTERFACE pw_third_party.nanopb ${DEPS})
+    else()
+      _pw_generate_protos("${NAME}._generate.nanopb"
+          nanopb
+          "${dir_pw_third_party_nanopb}/generator/protoc-gen-nanopb"
+          ".pb.h;.pb.c"
+          "${INCLUDE_FILE}"
+          "${OUT_DIR}"
+          "${SOURCES}"
+          "${INPUTS}"
+          "${DEPS}"
+      )
+
+      # Create the library with the generated source files.
+      add_library("${NAME}.nanopb" EXCLUDE_FROM_ALL ${generated_outputs})
+      target_include_directories("${NAME}.nanopb" PUBLIC "${OUT_DIR}/nanopb")
+      target_link_libraries("${NAME}.nanopb" PUBLIC pw_third_party.nanopb ${DEPS})
+    endif()
+
+    add_dependencies("${NAME}.nanopb" "${NAME}._generate.nanopb")
 
     # Ensure that nanopb_pb2.py is generated to avoid race conditions.
     add_dependencies("${NAME}._generate.nanopb"
         pw_third_party.nanopb.generate_proto
     )
   endif()
-
-  # Create the library with the generated source files.
-  add_library("${NAME}.nanopb" EXCLUDE_FROM_ALL ${generated_outputs})
-  target_include_directories("${NAME}.nanopb" PUBLIC "${OUT_DIR}/nanopb")
-  target_link_libraries("${NAME}.nanopb" PUBLIC pw_third_party.nanopb ${DEPS})
-  add_dependencies("${NAME}.nanopb" "${NAME}._generate.nanopb")
 endfunction(_pw_nanopb_library)
 
 # Internal function that creates a nanopb_rpc library.