Add spleeter (CLA demo)

CMakeLists.txt

@@ -1500,6 +1500,48 @@ if(ENGINEPRIME)
   endif()
 endif()
 
+# Spleeter
+option(SPLEETER "Spleeter stem separation" OFF)
+if(SPLEETER)
+  find_package(Spleeter)
+  if(Spleeter_Found)
+    message(STATUS "Linking dynamically to existing installation of spleeter")
+    target_link_libraries(mixxx-lib PUBLIC spleeter::Split)
+  else()
+      # Fetch spleeter sources from GitHub and build them statically.
+      message(STATUS "Linking statically to spleeter fetched from GitHub")
+      set(Spleeter_INSTALL_DIR "${CMAKE_CURRENT_BINARY_DIR}/lib/spleeter-install")
+      ExternalProject_Add(spleeter
+        GIT_REPOSITORY git@github.com:gvne/spleeterpp.git
+        GIT_TAG tags/v0.2.1
+        GIT_SHALLOW TRUE
+        INSTALL_DIR "${Spleeter_INSTALL_DIR}"
+        CMAKE_ARGS
+          -Dspleeter_enable_tests=OFF
+          -DCMAKE_BUILD_TYPE=${CMAKE_BUILD_TYPE}
+          -DCMAKE_INSTALL_PREFIX:PATH=<INSTALL_DIR>
+        EXCLUDE_FROM_ALL TRUE
+      )
+
+      # This is a bit of a hack to make sure that the include directory
+      # actually exists when configuring the build.  ExternalProject_Add() will
+      # create it at compile time, but CMake already checks that all
+      # directories passed to target_include_directories() exist during
+      # configuration and will throw an error if not.
+      file(MAKE_DIRECTORY "${Spleeter_INSTALL_DIR}/include")
+
+      # Assemble a library based on the external project.
+      add_library(mixxx-spleeter STATIC IMPORTED)
+      add_dependencies(mixxx-spleeter spleeter)
+      set_target_properties(mixxx-spleeter
+        PROPERTIES
+          IMPORTED_LOCATION "${Spleeter_INSTALL_DIR}/${CMAKE_INSTALL_LIBDIR}/${CMAKE_STATIC_LIBRARY_PREFIX}spleeter${CMAKE_STATIC_LIBRARY_SUFFIX}"
+          INTERFACE_INCLUDE_DIRECTORIES "${Spleeter_INSTALL_DIR}/include"
+      )
+      target_link_libraries(mixxx-lib PUBLIC mixxx-spleeter)
+  endif()
+endif()
+
 # Ebur128
 find_package(Ebur128)
 cmake_dependent_option(EBUR128_STATIC "Link libebur128 statically" OFF "Ebur128_FOUND" ON)

cmake/modules/FindSpleeter.cmake

@@ -0,0 +1,63 @@
+# This file is part of Mixxx, Digital DJ'ing software.
+# Copyright (C) 2001-2020 Mixxx Development Team
+# Distributed under the GNU General Public Licence (GPL) version 2 or any later
+# later version. See the LICENSE file for details.
+
+#[=======================================================================[.rst:
+FindSpleeterpp
+--------------
+
+Finds the Spleeterpp library.
+
+Imported Targets
+^^^^^^^^^^^^^^^^
+
+This module provides the following imported targets, if found:
+
+``spleeter::Split`
+  The Spleeterpp library
+
+#]=======================================================================]
+
+find_package(PkgConfig QUIET)
+if(PkgConfig_FOUND)
+  pkg_check_modules(PC_Spleeter QUIET spleeter)
+endif()
+
+find_path(Spleeter_INCLUDE_DIR
+  NAMES spleeter.h
+  PATHS ${PC_Spleeter_INCLUDE_DIRS}
+  PATH_SUFFIXES spleeter
+  DOC "Spleeter include directory")
+mark_as_advanced(Spleeter_INCLUDE_DIR)
+
+find_library(Spleeter_LIBRARY
+  NAMES spleeter
+  PATHS ${Spleeter_LIBRARY_DIRS}
+  DOC "Spleeter library"
+)
+mark_as_advanced(Spleeterpp_LIBRARY)
+
+include(FindPackageHandleStandardArgs)
+find_package_handle_standard_args(
+  Spleeter
+  DEFAULT_MSG
+  Spleeter_LIBRARY
+  Spleeter_INCLUDE_DIR
+)
+
+if(Spleeter_FOUND)
+  set(Spleeter_LIBRARIES "${Spleeter_LIBRARY}")
+  set(Spleeter_INCLUDE_DIRS "${Spleeter_INCLUDE_DIR}")
+  set(Spleeter_DEFINITIONS ${PC_Spleeter_CFLAGS_OTHER})
+
+  if(NOT TARGET spleeter::Split)
+    add_library(spleeter::Split UNKNOWN IMPORTED)
+    set_target_properties(spleeter::Split
+      PROPERTIES
+        IMPORTED_LOCATION "${Spleeter_LIBRARY}"
+        INTERFACE_COMPILE_OPTIONS "${Spleeter_CFLAGS_OTHER}"
+        INTERFACE_INCLUDE_DIRECTORIES "${Spleeter_INCLUDE_DIR}"
+    )
+  endif()
+endif()