Use FetchContent for msgpack

Using fetch content cmake module is less verbose,
than custom download and extract logic with setting
of additional variables.

CMake version 3.16 is in the Ubuntu 20.04 repository,
so everyone should have at least it by now.

Author: gikari

.gitignore

@@ -1,6 +1,5 @@
 .*
 build/
 src/gui/runtime/doc/tags
-third-party/msgpack*
 compile_commands.json
 !.github

CMakeLists.txt

@@ -1,10 +1,6 @@
-cmake_minimum_required(VERSION 2.8.12)
-if (POLICY CMP0048)
-  cmake_policy(SET CMP0048 NEW)
-endif (POLICY CMP0048)
-if (POLICY CMP0069)
-  cmake_policy(SET CMP0069 NEW)
-endif (POLICY CMP0069)
+cmake_minimum_required(VERSION 3.16)
+cmake_policy(SET CMP0048 NEW)
+cmake_policy(SET CMP0069 NEW)
 
 # Neovim-Qt Version, used by --version update before release
 # 9999 = Development Pre-Release
@@ -155,7 +151,6 @@ if(USE_SYSTEM_MSGPACK)
 else()
 	add_subdirectory(third-party)
 endif()
-include_directories(${MSGPACK_INCLUDE_DIRS})
 
 if(NOT CMAKE_BUILD_TYPE STREQUAL "Debug")
     add_definitions(-DQT_NO_DEBUG_OUTPUT)

cmake/FindMsgpack.cmake

@@ -22,6 +22,6 @@ if(WIN32)
 endif()
 
 add_library(neovim-qt STATIC ${NEOVIM_QT_SOURCES})
-target_link_libraries(neovim-qt Qt5::Network ${MSGPACK_LIBRARIES})
+target_link_libraries(neovim-qt Qt5::Network msgpackc-static)
 
 add_subdirectory(gui)

src/CMakeLists.txt

@@ -67,7 +67,7 @@ add_executable(nvim-qt WIN32 MACOSX_BUNDLE main.cpp
 	${RES_FILE}
 	${ICON_PATH})
 
-target_link_libraries(nvim-qt ${QTLIBS} ${MSGPACK_LIBRARIES} neovim-qt-gui)
+target_link_libraries(nvim-qt ${QTLIBS} neovim-qt-gui)
 
 if(APPLE)
 	add_custom_command(TARGET nvim-qt COMMAND ${CMAKE_COMMAND} -E copy_directory

src/gui/CMakeLists.txt

@@ -1,7 +1,6 @@
-cmake_minimum_required(VERSION 2.8.12)
-if (POLICY CMP0048)
-  cmake_policy(SET CMP0048 NEW)
-endif (POLICY CMP0048)
+cmake_minimum_required(VERSION 3.16)
+cmake_policy(SET CMP0048 NEW)
+
 project(qshellwidget)
 
 set(CMAKE_INCLUDE_CURRENT_DIR ON)

src/gui/shellwidget/CMakeLists.txt

@@ -1,34 +1,23 @@
 # This is a minimal CMake project to fetch and build third party
 # dependencies
-cmake_minimum_required(VERSION 2.8.12)
-if (POLICY CMP0048)
-  cmake_policy(SET CMP0048 NEW)
-endif (POLICY CMP0048)
+cmake_minimum_required(VERSION 3.16)
+
+cmake_policy(SET CMP0048 NEW)
+if (POLICY CMP0135)
+  cmake_policy(SET CMP0135 NEW)
+endif()
+
 project(neovim-qt-deps)
 
-#
-# Get Msgpack
-#
-set(MSGPACK_VERSION 3.2.0)
-set(MSGPACK_URL https://github.com/msgpack/msgpack-c/archive/cpp-${MSGPACK_VERSION}.tar.gz)
-set(MSGPACK_SHA256 ff865a36bad5c72b8e7ebc4b7cf5f27a820fce4faff9c571c1791e3728355a39)
+include(FetchContent)
 
-message(STATUS "Downloading Msgpack...")
-set(MSGPACK_TARBALL msgpack-${MSGPACK_VERSION}.tar.gz)
-file(DOWNLOAD ${MSGPACK_URL} ${CMAKE_CURRENT_SOURCE_DIR}/${MSGPACK_TARBALL}
-	INACTIVITY_TIMEOUT 30
-	EXPECTED_HASH SHA256=${MSGPACK_SHA256})
-execute_process(COMMAND ${CMAKE_COMMAND} -E tar xfz ${MSGPACK_TARBALL}
-	WORKING_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR}
-	RESULT_VARIABLE rv)
-if(NOT rv EQUAL 0)
-  message(FATAL_ERROR "Failed to extract ${MSGPACK_TARBALL}")
-endif()
+set(MSGPACK_VERSION 3.2.0)
+FetchContent_Declare(
+    msgpackc
+    URL "https://github.com/msgpack/msgpack-c/archive/cpp-${MSGPACK_VERSION}.tar.gz"
+    URL_HASH SHA256=ff865a36bad5c72b8e7ebc4b7cf5f27a820fce4faff9c571c1791e3728355a39
+)
 
-set(LIBRARY_OUTPUT_PATH ${PROJECT_BINARY_DIR})
-set(MSGPACK_SOURCE_DIR ${CMAKE_CURRENT_SOURCE_DIR}/msgpack-c-cpp-${MSGPACK_VERSION}/)
-add_subdirectory(${MSGPACK_SOURCE_DIR} EXCLUDE_FROM_ALL)
+set(MSGPACK_BUILD_EXAMPLES OFF)
 
-# Similar enough to FindMsgpack
-set(MSGPACK_INCLUDE_DIRS ${MSGPACK_SOURCE_DIR}/include PARENT_SCOPE)
-set(MSGPACK_LIBRARIES msgpackc-static PARENT_SCOPE)
+FetchContent_MakeAvailable(msgpackc)