From 96ebeb922dabe5756a13bdca5b1efd9f9014c4df Mon Sep 17 00:00:00 2001
From: Carles Fernandez <carles.fernandez@gmail.com>
Date: Sat, 20 Apr 2019 18:47:18 +0200
Subject: [PATCH] Improve Protocol Buffers detection in cross-compilation

---
 CMakeLists.txt | 77 ++++++++++++++++++++++++++++++++++----------------
 1 file changed, 53 insertions(+), 24 deletions(-)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index f01969bfb..1709219ce 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -1796,18 +1796,27 @@ if(ENABLE_PROTOBUF)
         URL "https://developers.google.com/protocol-buffers/"
         DESCRIPTION "A language-neutral, platform-neutral extensible mechanism for serializing structured data"
         PURPOSE "Used to serialize output data."
-        TYPE OPTIONAL
+        TYPE REQUIRED
     )
-    if((NOT Protobuf_FOUND) OR (NOT ${Protobuf_PROTOC_EXECUTABLE}) OR (${Protobuf_VERSION} VERSION_LESS ${GNSSSDR_PROTOBUF_MIN_VERSION}))
+    if(Protobuf_FOUND AND CMAKE_CROSSCOMPILING)
+        unset(protobuf::protoc)
+        find_program(PROTOC_EXECUTABLE protoc
+            HINTS
+            /usr/bin/
+            /usr/local/bin/
+            NO_SYSTEM_ENVIRONMENT_PATH
+        )
+        if(PROTOC_EXECUTABLE)
+            add_executable(protobuf::protoc IMPORTED)
+            set_target_properties(protobuf::protoc PROPERTIES
+                IMPORTED_LINK_INTERFACE_LANGUAGES "CXX"
+                IMPORTED_LOCATION ${PROTOC_EXECUTABLE}
+            )
+        endif()
+    endif()
+    if((NOT Protobuf_FOUND) OR (NOT Protobuf_PROTOC_EXECUTABLE) OR (${Protobuf_VERSION} VERSION_LESS ${GNSSSDR_PROTOBUF_MIN_VERSION}))
         if(CMAKE_CROSSCOMPILING)
             set(PROTOBUF_CROSSCOMPILE "--host=$ENV{OECORE_TARGET_ARCH} --with-protoc=/usr/local/bin/protoc")
-        endif()
-        if(${Protobuf_VERSION} VERSION_LESS ${GNSSSDR_PROTOBUF_MIN_VERSION})
-            unset(protobuf::libprotobuf)
-            unset(protobuf::protoc)
-        endif()
-
-        if(CMAKE_VERSION VERSION_LESS 3.2)
             ExternalProject_Add(protobuf-${GNSSSDR_PROTOCOLBUFFERS_LOCAL_VERSION}
                 PREFIX ${CMAKE_CURRENT_BINARY_DIR}/protobuf-${GNSSSDR_PROTOCOLBUFFERS_LOCAL_VERSION}
                 GIT_REPOSITORY https://github.com/protocolbuffers/protobuf
@@ -1815,26 +1824,46 @@ if(ENABLE_PROTOBUF)
                 SOURCE_DIR ${CMAKE_CURRENT_SOURCE_DIR}/thirdparty/protobuf/protobuf-${GNSSSDR_PROTOCOLBUFFERS_LOCAL_VERSION}
                 BINARY_DIR ${CMAKE_CURRENT_BINARY_DIR}/protobuf-${GNSSSDR_PROTOCOLBUFFERS_LOCAL_VERSION}
                 UPDATE_COMMAND ${CMAKE_CURRENT_SOURCE_DIR}/thirdparty/protobuf/protobuf-${GNSSSDR_PROTOCOLBUFFERS_LOCAL_VERSION}/autogen.sh
-                CONFIGURE_COMMAND ${CMAKE_CURRENT_SOURCE_DIR}/thirdparty/protobuf/protobuf-${GNSSSDR_PROTOCOLBUFFERS_LOCAL_VERSION}/configure --prefix=<INSTALL_DIR> ${PROTOBUF_CROSSCOMPILE}
-                BUILD_COMMAND ${CMAKE_MAKE_PROGRAM}
-                INSTALL_COMMAND ${CMAKE_MAKE_PROGRAM} install
-            )
-        else()
-            ExternalProject_Add(protobuf-${GNSSSDR_PROTOCOLBUFFERS_LOCAL_VERSION}
-                PREFIX ${CMAKE_CURRENT_BINARY_DIR}/protobuf-${GNSSSDR_PROTOCOLBUFFERS_LOCAL_VERSION}
-                GIT_REPOSITORY https://github.com/protocolbuffers/protobuf
-                GIT_TAG v${GNSSSDR_PROTOCOLBUFFERS_LOCAL_VERSION}
-                SOURCE_DIR ${CMAKE_CURRENT_SOURCE_DIR}/thirdparty/protobuf/protobuf-${GNSSSDR_PROTOCOLBUFFERS_LOCAL_VERSION}
-                BINARY_DIR ${CMAKE_CURRENT_BINARY_DIR}/protobuf-${GNSSSDR_PROTOCOLBUFFERS_LOCAL_VERSION}
-                UPDATE_COMMAND ${CMAKE_CURRENT_SOURCE_DIR}/thirdparty/protobuf/protobuf-${GNSSSDR_PROTOCOLBUFFERS_LOCAL_VERSION}/autogen.sh
-                CONFIGURE_COMMAND ${CMAKE_CURRENT_SOURCE_DIR}/thirdparty/protobuf/protobuf-${GNSSSDR_PROTOCOLBUFFERS_LOCAL_VERSION}/configure --prefix=<INSTALL_DIR> ${PROTOBUF_CROSSCOMPILE}
+                CONFIGURE_COMMAND ${CMAKE_CURRENT_SOURCE_DIR}/thirdparty/protobuf/protobuf-${GNSSSDR_PROTOCOLBUFFERS_LOCAL_VERSION}/configure --prefix=<INSTALL_DIR> --host=$ENV{OECORE_TARGET_ARCH} --with-protoc=${PROTOC_EXECUTABLE}
                 BUILD_COMMAND ${CMAKE_MAKE_PROGRAM}
                 INSTALL_COMMAND ${CMAKE_MAKE_PROGRAM} install
                 BUILD_BYPRODUCTS ${CMAKE_CURRENT_BINARY_DIR}/protobuf-${GNSSSDR_PROTOCOLBUFFERS_LOCAL_VERSION}/lib/${CMAKE_FIND_LIBRARY_PREFIXES}protobuf${CMAKE_STATIC_LIBRARY_SUFFIX}
-                    ${CMAKE_CURRENT_BINARY_DIR}/protobuf-${GNSSSDR_PROTOCOLBUFFERS_LOCAL_VERSION}/bin/protoc
+                ${CMAKE_CURRENT_BINARY_DIR}/protobuf-${GNSSSDR_PROTOCOLBUFFERS_LOCAL_VERSION}/bin/protoc
             )
-        endif()
+        else()
+            if(${Protobuf_VERSION} VERSION_LESS ${GNSSSDR_PROTOBUF_MIN_VERSION})
+                unset(protobuf::libprotobuf)
+                unset(protobuf::protoc)
+            endif()
 
+            if(CMAKE_VERSION VERSION_LESS 3.2)
+                ExternalProject_Add(protobuf-${GNSSSDR_PROTOCOLBUFFERS_LOCAL_VERSION}
+                    PREFIX ${CMAKE_CURRENT_BINARY_DIR}/protobuf-${GNSSSDR_PROTOCOLBUFFERS_LOCAL_VERSION}
+                    GIT_REPOSITORY https://github.com/protocolbuffers/protobuf
+                    GIT_TAG v${GNSSSDR_PROTOCOLBUFFERS_LOCAL_VERSION}
+                    SOURCE_DIR ${CMAKE_CURRENT_SOURCE_DIR}/thirdparty/protobuf/protobuf-${GNSSSDR_PROTOCOLBUFFERS_LOCAL_VERSION}
+                    BINARY_DIR ${CMAKE_CURRENT_BINARY_DIR}/protobuf-${GNSSSDR_PROTOCOLBUFFERS_LOCAL_VERSION}
+                    UPDATE_COMMAND ${CMAKE_CURRENT_SOURCE_DIR}/thirdparty/protobuf/protobuf-${GNSSSDR_PROTOCOLBUFFERS_LOCAL_VERSION}/autogen.sh
+                    CONFIGURE_COMMAND ${CMAKE_CURRENT_SOURCE_DIR}/thirdparty/protobuf/protobuf-${GNSSSDR_PROTOCOLBUFFERS_LOCAL_VERSION}/configure --prefix=<INSTALL_DIR> ${PROTOBUF_CROSSCOMPILE}
+                    BUILD_COMMAND ${CMAKE_MAKE_PROGRAM}
+                    INSTALL_COMMAND ${CMAKE_MAKE_PROGRAM} install
+                )
+            else()
+                ExternalProject_Add(protobuf-${GNSSSDR_PROTOCOLBUFFERS_LOCAL_VERSION}
+                    PREFIX ${CMAKE_CURRENT_BINARY_DIR}/protobuf-${GNSSSDR_PROTOCOLBUFFERS_LOCAL_VERSION}
+                    GIT_REPOSITORY https://github.com/protocolbuffers/protobuf
+                    GIT_TAG v${GNSSSDR_PROTOCOLBUFFERS_LOCAL_VERSION}
+                    SOURCE_DIR ${CMAKE_CURRENT_SOURCE_DIR}/thirdparty/protobuf/protobuf-${GNSSSDR_PROTOCOLBUFFERS_LOCAL_VERSION}
+                    BINARY_DIR ${CMAKE_CURRENT_BINARY_DIR}/protobuf-${GNSSSDR_PROTOCOLBUFFERS_LOCAL_VERSION}
+                    UPDATE_COMMAND ${CMAKE_CURRENT_SOURCE_DIR}/thirdparty/protobuf/protobuf-${GNSSSDR_PROTOCOLBUFFERS_LOCAL_VERSION}/autogen.sh
+                    CONFIGURE_COMMAND ${CMAKE_CURRENT_SOURCE_DIR}/thirdparty/protobuf/protobuf-${GNSSSDR_PROTOCOLBUFFERS_LOCAL_VERSION}/configure --prefix=<INSTALL_DIR> ${PROTOBUF_CROSSCOMPILE}
+                    BUILD_COMMAND ${CMAKE_MAKE_PROGRAM}
+                    INSTALL_COMMAND ${CMAKE_MAKE_PROGRAM} install
+                    BUILD_BYPRODUCTS ${CMAKE_CURRENT_BINARY_DIR}/protobuf-${GNSSSDR_PROTOCOLBUFFERS_LOCAL_VERSION}/lib/${CMAKE_FIND_LIBRARY_PREFIXES}protobuf${CMAKE_STATIC_LIBRARY_SUFFIX}
+                    ${CMAKE_CURRENT_BINARY_DIR}/protobuf-${GNSSSDR_PROTOCOLBUFFERS_LOCAL_VERSION}/bin/protoc
+                )
+            endif()
+        endif()
         if(NOT TARGET protobuf::libprotobuf)
             file(MAKE_DIRECTORY ${CMAKE_CURRENT_BINARY_DIR}/protobuf-${GNSSSDR_PROTOCOLBUFFERS_LOCAL_VERSION}/include)
             add_library(protobuf::libprotobuf STATIC IMPORTED)