Split WrapProtobuf module into components

- WrapProtobuf should only find required for the project needs
  components. E.g. at the build time it's optional to have protoc
  or libprotobuf in place. We may skip build of their dependencies
  instead.

Fixes: #205

CMakeLists.txt

@@ -22,8 +22,8 @@ set(QT_PROTOBUF_BINARY_DIR "${CMAKE_CURRENT_BINARY_DIR}")
 
 list(APPEND CMAKE_MODULE_PATH ${QT_PROTOBUF_CMAKE_DIR})
 
-find_package(WrapProtobuf REQUIRED)
 find_package(WrapgRPC)
+find_package(WrapProtobuf COMPONENTS Protoc OPTIONAL_COMPONENTS Generator Protobuf REQUIRED)
 find_package(Threads)
 find_package(${QT_VERSIONED_PREFIX} COMPONENTS Core Qml CONFIG REQUIRED)
 find_package(${QT_VERSIONED_PREFIX} OPTIONAL_COMPONENTS Network Quick Gui CONFIG)
@@ -116,10 +116,10 @@ if(TARGET ${QT_VERSIONED_PREFIX}::Network)
     endif()
 endif()
 
-if(TARGET protobuf::libprotobuf)
+if(TARGET protobuf::libprotobuf AND TARGET protobuf::protoc)
     add_subdirectory("src/wellknowntypes")
 endif()
-if(TARGET ${QT_VERSIONED_PREFIX}::Gui)
+if(TARGET ${QT_VERSIONED_PREFIX}::Gui AND TARGET protobuf::protoc)
     add_subdirectory("src/qttypes")
 endif()
 

cmake/FindWrapProtobuf.cmake

@@ -3,48 +3,102 @@ cmake_minimum_required(VERSION 3.10)
 find_package(Protobuf QUIET)
 
 unset(WrapProtobuf_FOUND)
-if(NOT Protobuf_FOUND OR NOT TARGET protobuf::libprotobuf
-    OR NOT TARGET protobuf::protoc OR NOT TARGET protobuf::libprotoc)
 
-    if(CMAKE_SIZEOF_VOID_P EQUAL 8)
-        set(FIND_LIBRARY_USE_LIB64_PATHS TRUE)
-        set(FIND_LIBRARY_USE_LIBX32_PATHS FALSE)
-        set(FIND_LIBRARY_USE_LIB32_PATHS FALSE)
-    else()
-        set(FIND_LIBRARY_USE_LIBX32_PATHS TRUE)
-        set(FIND_LIBRARY_USE_LIB32_PATHS TRUE)
-        set(FIND_LIBRARY_USE_LIB64_PATHS FALSE)
-    endif()
+if(CMAKE_SIZEOF_VOID_P EQUAL 8)
+    set(FIND_LIBRARY_USE_LIB64_PATHS TRUE)
+    set(FIND_LIBRARY_USE_LIBX32_PATHS FALSE)
+    set(FIND_LIBRARY_USE_LIB32_PATHS FALSE)
+else()
+    set(FIND_LIBRARY_USE_LIBX32_PATHS TRUE)
+    set(FIND_LIBRARY_USE_LIB32_PATHS TRUE)
+    set(FIND_LIBRARY_USE_LIB64_PATHS FALSE)
+endif()
 
-    find_library(Protobuf_LIBRARY protobuf)
-    if(NOT TARGET protobuf::libprotobuf AND Protobuf_LIBRARY)
-        add_library(protobuf::libprotobuf UNKNOWN IMPORTED)
-        set_target_properties(protobuf::libprotobuf PROPERTIES
-            IMPORTED_LOCATION ${Protobuf_LIBRARY}
-        )
-        if(DEFINED Protobuf_INCLUDE_DIRS)
+if("Protobuf" IN_LIST WrapProtobuf_FIND_COMPONENTS OR NOT WrapProtobuf_FIND_COMPONENTS)
+    set(WrapProtobuf_Protobuf_FOUND TRUE)
+    if(NOT TARGET protobuf::libprotobuf)
+        find_library(Protobuf_LIBRARY protobuf)
+        if(Protobuf_LIBRARY)
+            add_library(protobuf::libprotobuf UNKNOWN IMPORTED)
             set_target_properties(protobuf::libprotobuf PROPERTIES
-                INTERFACE_INCLUDE_DIRECTORIES ${Protobuf_INCLUDE_DIRS})
+                IMPORTED_LOCATION "${Protobuf_LIBRARY}"
+            )
+            find_path(Protobuf_INCLUDE_DIRS "message.h"
+                PATH_SUFFIXES "google/protobuf"
+            )
+            if(Protobuf_INCLUDE_DIRS)
+                set_target_properties(protobuf::libprotobuf PROPERTIES
+                    INTERFACE_INCLUDE_DIRECTORIES "${Protobuf_INCLUDE_DIRS}"
+                )
+            else()
+                set(WrapProtobuf_Protobuf_FOUND FALSE)
+            endif()
+        else()
+            set(WrapProtobuf_Protobuf_FOUND FALSE)
+        endif()
+    else()
+        if(NOT Protobuf_INCLUDE_DIRS)
+            get_target_property(Protobuf_INCLUDE_DIRS protobuf::libprotobuf INTERFACE_INCLUDE_DIRECTORIES)
         endif()
     endif()
+endif()
 
-    find_program(Protobuf_PROTOC_EXECUTABLE protoc)
-    if(NOT TARGET protobuf::protoc AND Protobuf_PROTOC_EXECUTABLE)
-        add_executable(protobuf::protoc IMPORTED)
-        set_target_properties(protobuf::protoc PROPERTIES IMPORTED_LOCATION ${Protobuf_PROTOC_EXECUTABLE})
-    endif()
+if("Protoc" IN_LIST WrapProtobuf_FIND_COMPONENTS OR NOT WrapProtobuf_FIND_COMPONENTS)
+    set(WrapProtobuf_Protoc_FOUND TRUE)
+    if(NOT TARGET protobuf::libprotoc)
+        find_package(Threads REQUIRED)
+        find_library(Protoc_LIBRARY protoc)
+        if(Protoc_LIBRARY)
+            add_library(protobuf::libprotoc UNKNOWN IMPORTED)
+            set_target_properties(protobuf::libprotoc PROPERTIES
+                IMPORTED_LOCATION "${Protoc_LIBRARY}"
+                INTERFACE_LINK_LIBRARIES Threads::Threads
+            )
+
+            message(WARNING "aedelev: Protoc_INCLUDE_DIRS")
+            find_path(Protoc_INCLUDE_DIRS "descriptor.h"
+                PATH_SUFFIXES "google/protobuf"
+            )
 
-    find_package(Threads)
-    find_library(Protobuf_PROTOC_LIBRARY protoc)
-    if(NOT TARGET protobuf::libprotoc AND Protobuf_PROTOC_LIBRARY)
-        add_library(protobuf::libprotoc UNKNOWN IMPORTED)
-        set_target_properties(protobuf::libprotoc PROPERTIES IMPORTED_LOCATION ${Protobuf_PROTOC_LIBRARY}
-            INTERFACE_LINK_LIBRARIES Threads::Threads)
+            if(Protoc_INCLUDE_DIRS)
+                set_target_properties(protobuf::libprotoc PROPERTIES
+                    INTERFACE_INCLUDE_DIRECTORIES "${Protoc_INCLUDE_DIRS}"
+                )
+            else()
+                set(WrapProtobuf_Protoc_FOUND FALSE)
+            endif()
+        else()
+            set(WrapProtobuf_Protoc_FOUND FALSE)
+        endif()
+    else()
+        if(NOT Protoc_INCLUDE_DIRS)
+            get_target_property(Protoc_INCLUDE_DIRS protobuf::libprotoc INTERFACE_INCLUDE_DIRECTORIES)
+        endif()
     endif()
+endif()
 
-    if(TARGET protobuf::libprotoc AND TARGET protobuf::protoc AND TARGET protobuf::libprotobuf)
-        set(WrapProtobuf_FOUND TRUE)
+if("Generator" IN_LIST WrapProtobuf_FIND_COMPONENTS OR NOT WrapProtobuf_FIND_COMPONENTS)
+    set(WrapProtobuf_Generator_FOUND TRUE)
+    if(NOT TARGET protobuf::protoc)
+        find_program(Protobuf_Protoc_EXECUTABLE protoc)
+        if(Protobuf_Protoc_EXECUTABLE)
+            add_executable(protobuf::protoc IMPORTED)
+            set_target_properties(protobuf::protoc PROPERTIES
+                IMPORTED_LOCATION "${Protobuf_Protoc_EXECUTABLE}"
+            )
+        else()
+            set(WrapProtobuf_Generator_FOUND FALSE)
+        endif()
     endif()
-else()
-    set(WrapProtobuf_FOUND TRUE)
+endif()
+
+if(WrapProtobuf_FIND_COMPONENTS)
+    include(FindPackageHandleStandardArgs)
+    find_package_handle_standard_args(WrapProtobuf HANDLE_COMPONENTS
+        REQUIRED_VARS Protoc_INCLUDE_DIRS Protobuf_INCLUDE_DIRS
+    )
+elseif(TARGET protobuf::protoc AND TARGET protobuf::libprotoc AND TARGET protobuf::libprotobuf)
+    include(FindPackageHandleStandardArgs)
+    find_package_handle_standard_args(WrapProtobuf REQUIRED_VARS
+        Protoc_INCLUDE_DIRS Protobuf_INCLUDE_DIRS)
 endif()

src/generator/QtqtprotobufgenConfig.cmake.in

@@ -1,5 +1,6 @@
 include(CMakeFindDependencyMacro)
-find_dependency(WrapProtobuf REQUIRED)
+# We only look for protoc, libprotoc should already be in rpath or linked statically
+find_package(WrapProtobuf COMPONENTS Generator REQUIRED)
 
 if(NOT TARGET @QT_PROTOBUF_NAMESPACE@::@target@)
     include("${CMAKE_CURRENT_LIST_DIR}/@target_export@.cmake")

src/wellknowntypes/QtProtobufWellKnownTypesConfig.cmake.in

@@ -1,5 +1,5 @@
 include(CMakeFindDependencyMacro)
-find_dependency(WrapProtobuf REQUIRED)
+find_dependency(WrapProtobuf COMPONENTS Protobuf REQUIRED)
 
 if(NOT TARGET @QT_PROTOBUF_NAMESPACE@::@target@)
     include("${CMAKE_CURRENT_LIST_DIR}/@target_export@.cmake")
@@ -9,9 +9,7 @@ endif()
 # $<TARGET_PROPERTY:${QT_PROTOBUF_NAMESPACE}::ProtobufWellKnownTypes,PROTO_INCLUDES>
 # outside the build tree. Expecting that WrapProtobuf sets Protobuf_INCLUDE_DIRS.
 
-if(DEFINED Protobuf_INCLUDE_DIRS)
-    string(JOIN " -I" proto_includes ${Protobuf_INCLUDE_DIRS})
-endif()
+string(JOIN " -I" proto_includes ${Protobuf_INCLUDE_DIRS})
 
 set_target_properties(@QT_PROTOBUF_NAMESPACE@::@target@ PROPERTIES
     PROTO_INCLUDES "-I${proto_includes}"