From cda87fa3afdacf20a097cf6ed90c5c2ef64e0437 Mon Sep 17 00:00:00 2001
From: Gil <mcg@google.com>
Date: Mon, 16 Jul 2018 08:50:53 -0700
Subject: Convert grpc and protobuf CMake builds to add_subdirectory (#1537)

* Build zlib with grpc's add_subdirectory

* Build grpc and its children with add_subdirectory.

* Build c-ares with grpc's add_subdirectory

* Convert protobuf to a download-only ExternalProject

* Temporarily break protobuf within grpc

This works because libgrpc has no actual dependency on protobuf

* Update boringssl to master@{2018-07-10}
---
 cmake/external/protobuf.cmake | 89 +++++--------------------------------------
 1 file changed, 9 insertions(+), 80 deletions(-)

(limited to 'cmake/external/protobuf.cmake')

diff --git a/cmake/external/protobuf.cmake b/cmake/external/protobuf.cmake
index 2cc632c..b85255e 100644
--- a/cmake/external/protobuf.cmake
+++ b/cmake/external/protobuf.cmake
@@ -18,86 +18,14 @@ if(TARGET protobuf)
   return()
 endif()
 
-# Protubuf has CMake support, but includes it in a `cmake` subdirectory, which
-# does not work with CMake's ExternalProject by default. CMake 3.7 added
-# SOURCE_SUBDIR as a means of supporting this but that's too new to require
-# yet.
-
-# Compose CMAKE_ARGS
-set(
-  cmake_args
-  -DCMAKE_INSTALL_PREFIX:PATH=<INSTALL_DIR>
-  -DBUILD_SHARED_LIBS:BOOL=OFF
-  -Dprotobuf_BUILD_TESTS:BOOL=OFF
-  -Dprotobuf_WITH_ZLIB:BOOL=OFF
-  -Dprotobuf_MSVC_STATIC_RUNTIME:BOOL=ON
-)
-
-# For single-configuration generators, pass CONFIG at configure time
-if(NOT CMAKE_CONFIGURATION_TYPES)
-  list(APPEND cmake_args -DCMAKE_BUILD_TYPE=$<CONFIG>)
-endif()
-
-
-if(CMAKE_VERSION VERSION_LESS "3.7")
-  # Manually compose the commands required to invoke CMake in the external
-  # project.
-  #
-  # Compose CONFIGURE_COMMAND so as to preserve the outer CMake's generator
-  # configuration in the sub-build. Without this the builds can invoke
-  # different compilers or disagree about word size or other fundamental
-  # parameters making the output of the sub-build useless. This is based on
-  # _ep_extract_configure_command in ExternalProject.cmake.
-  set(configure "${CMAKE_COMMAND}")
-
-  if(CMAKE_EXTRA_GENERATOR)
-    list(APPEND configure "-G${CMAKE_EXTRA_GENERATOR} - ${CMAKE_GENERATOR}")
-  else()
-    list(APPEND configure "-G${CMAKE_GENERATOR}")
-  endif()
-
-  if(CMAKE_GENERATOR_PLATFORM)
-    list(APPEND configure "-A${CMAKE_GENERATOR_PLATFORM}")
-  endif()
-
-  if(CMAKE_GENERATOR_TOOLSET)
-    list(APPEND configure "-T${CMAKE_GENERATOR_TOOLSET}")
-  endif()
-
-  list(
-    APPEND configure
-    ${cmake_args}
-    "${PROJECT_BINARY_DIR}/src/protobuf/cmake"
-  )
-
-  # Compose BUILD_COMMAND and INSTALL_COMMAND
-  set(build "${CMAKE_COMMAND}" --build .)
-
-  # For multi-configuration generators, pass CONFIG at build time.
-  if(CMAKE_CONFIGURATION_TYPES)
-    list(APPEND build --config $<CONFIG>)
-  endif()
-
-  set(install ${build} --target install)
-
-  set(
-    commands
-    CONFIGURE_COMMAND ${configure}
-    BUILD_COMMAND ${build}
-    INSTALL_COMMAND ${install}
-  )
-
-else()
-  # CMake 3.7 and above support this directly.
-  set(
-    commands
-    CMAKE_ARGS ${cmake_args}
-    SOURCE_SUBDIR cmake
-  )
-endif()
+# This ExternalProject unpacks itself inside the gRPC source tree. CMake clears
+# the SOURCE_DIR when unpacking so this must come after grpc despite the fact
+# that grpc logically depends upon this.
 
 ExternalProject_Add(
   protobuf
+  DEPENDS
+    grpc-download
 
   DOWNLOAD_DIR ${FIREBASE_DOWNLOAD_DIR}
   DOWNLOAD_NAME protobuf-v3.5.1.1.tar.gz
@@ -105,9 +33,10 @@ ExternalProject_Add(
   URL_HASH SHA256=56b5d9e1ab2bf4f5736c4cfba9f4981fbc6976246721e7ded5602fbaee6d6869
 
   PREFIX ${PROJECT_BINARY_DIR}
-  INSTALL_DIR ${FIREBASE_INSTALL_DIR}
-
-  ${commands}
+  SOURCE_DIR ${PROJECT_BINARY_DIR}/src/grpc/third_party/protobuf
 
+  CONFIGURE_COMMAND ""
+  BUILD_COMMAND ""
+  INSTALL_COMMAND ""
   TEST_COMMAND ""
 )
-- 
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