From ce568a16a6a68915760a1638734fe1a1ad61b866 Mon Sep 17 00:00:00 2001
From: Lorenzo Fontana <lo@linux.com>
Date: Thu, 12 Dec 2019 17:06:33 +0100
Subject: [PATCH] build: allow building gRPC as an alternative to dynamic
 linking

Co-Authored-By: Leonardo Di Donato <leodidonato@gmail.com>
Signed-off-by: Lorenzo Fontana <lo@linux.com>
---
 cmake/modules/FindGRPC.cmake | 85 +++++++++++++++++++++++++-----------
 1 file changed, 59 insertions(+), 26 deletions(-)

diff --git a/cmake/modules/FindGRPC.cmake b/cmake/modules/FindGRPC.cmake
index c0b34e58..ce472543 100644
--- a/cmake/modules/FindGRPC.cmake
+++ b/cmake/modules/FindGRPC.cmake
@@ -1,35 +1,68 @@
 #
 # Copyright (C) 2019 The Falco 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
+# 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
 #
 # http://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.
+# 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.
 #
-find_path(GRPCXX_INCLUDE NAMES grpc++/grpc++.h)
-if(GRPCXX_INCLUDE)
-	set(GRPC_INCLUDE ${GRPCXX_INCLUDE})
+
+option(BUILD_STATIC_GRPC
+       "Build a static version of gRPC (useful for building in Operating Systems that don't have the gRPC package)" OFF)
+
+if(NOT BUILD_STATIC_GRPC)
+  find_path(GRPCXX_INCLUDE NAMES grpc++/grpc++.h)
+  if(GRPCXX_INCLUDE)
+    set(GRPC_INCLUDE ${GRPCXX_INCLUDE})
+  else()
+    find_path(GRPCPP_INCLUDE NAMES grpcpp/grpcpp.h)
+    set(GRPC_INCLUDE ${GRPCPP_INCLUDE})
+    add_definitions(-DGRPC_INCLUDE_IS_GRPCPP=1)
+  endif()
+  find_library(GRPC_LIB NAMES grpc)
+  find_library(GRPCPP_LIB NAMES grpc++)
+  if(GRPC_INCLUDE
+     AND GRPC_LIB
+     AND GRPCPP_LIB)
+    message(STATUS "Found grpc: include: ${GRPC_INCLUDE}, C lib: ${GRPC_LIB}, C++ lib: ${GRPCPP_LIB}")
+  else()
+    message(FATAL_ERROR "Couldn't find system grpc")
+  endif()
+  find_program(GRPC_CPP_PLUGIN grpc_cpp_plugin)
+  if(NOT GRPC_CPP_PLUGIN)
+    message(FATAL_ERROR "System grpc_cpp_plugin not found")
+  endif()
 else()
-	find_path(GRPCPP_INCLUDE NAMES grpcpp/grpcpp.h)
-	set(GRPC_INCLUDE ${GRPCPP_INCLUDE})
-	add_definitions(-DGRPC_INCLUDE_IS_GRPCPP=1)
-endif()
-find_library(GRPC_LIB NAMES grpc)
-find_library(GRPCPP_LIB NAMES grpc++)
-if(GRPC_INCLUDE AND GRPC_LIB AND GRPCPP_LIB)
-	message(STATUS "Found grpc: include: ${GRPC_INCLUDE}, C lib: ${GRPC_LIB}, C++ lib: ${GRPCPP_LIB}")
-else()
-	message(FATAL_ERROR "Couldn't find system grpc")
-endif()
-find_program(GRPC_CPP_PLUGIN grpc_cpp_plugin)
-if(NOT GRPC_CPP_PLUGIN)
-	message(FATAL_ERROR "System grpc_cpp_plugin not found")
+  find_package(PkgConfig)
+  if(NOT PKG_CONFIG_FOUND)
+    message(FATAL_ERROR "pkg-config binary not found")
+  endif()
+  message(STATUS "Found pkg-config executable: ${PKG_CONFIG_EXECUTABLE}")
+  set(GRPC_SRC "${PROJECT_BINARY_DIR}/grpc-prefix/src/grpc")
+  message(STATUS "Using bundled grpc in '${GRPC_SRC}'")
+  set(GRPC_INCLUDE "${GRPC_SRC}/include")
+  set(GRPC_LIB "${GRPC_SRC}/libs/opt/libgrpc.a")
+  set(GRPCPP_LIB "${GRPC_SRC}/libs/opt/libgrpc++.a")
+  set(GRPC_CPP_PLUGIN "${GRPC_SRC}/bins/opt/grpc_cpp_plugin")
+
+  ExternalProject_Add(
+    grpc
+    URL "https://github.com/grpc/grpc/archive/v1.25.0.tar.gz"
+    URL_MD5 "3a875f7b3f0e3bdd3a603500bcef3d41"
+    CONFIGURE_COMMAND ""
+    BUILD_COMMAND
+      CFLAGS=-Wno-implicit-fallthrough
+      PKG_CONFIG=${PKG_CONFIG_EXECUTABLE}
+      make
+      grpc_cpp_plugin
+      static_cxx
+      static_c
+    BUILD_IN_SOURCE 1
+    BUILD_BYPRODUCTS ${GRPC_LIB} ${GRPCPP_LIB}
+    INSTALL_COMMAND "")
+
 endif()