[cmake] refactor: Use CPM over submodules (#143)

Transfers the majority of submodules and large externals to CPM, using source archives rather than full Git clones. Not only does this save massive amounts of clone and configure time, but dependencies are grabbed on-demand rather than being required by default. Additionally, CPM will (generally) automatically search for system dependencies, though certain dependencies have options to control this.

Testing shows gains ranging from 5x to 10x in terms of overall clone/configure time.

Reviewed-on: https://git.eden-emu.dev/eden-emu/eden/pulls/143
Reviewed-by: CamilleLaVey <camillelavey99@gmail.com>

1 files changed, 46 insertions, 30 deletions

diff --git a/CMakeModules/DownloadExternals.cmake b/CMakeModules/DownloadExternals.cmake
index 3e9bc26d69..d4c1042740 100644
--- a/CMakeModules/DownloadExternals.cmake
+++ b/CMakeModules/DownloadExternals.cmake
@@ -6,36 +6,52 @@
 #   remote_path: path to the file to download, relative to the remote repository root
 #   prefix_var: name of a variable which will be set with the path to the extracted contents
 set(CURRENT_MODULE_DIR ${CMAKE_CURRENT_LIST_DIR})
-function(download_bundled_external remote_path lib_name prefix_var)
-
-set(package_base_url "https://github.com/eden-emulator/")
-set(package_repo "no_platform")
-set(package_extension "no_platform")
-if (WIN32)
-    set(package_repo "ext-windows-bin/raw/master/")
-    set(package_extension ".7z")
-elseif (${CMAKE_SYSTEM_NAME} STREQUAL "Linux")
-    set(package_repo "ext-linux-bin/raw/master/")
-    set(package_extension ".tar.xz")
-elseif (ANDROID)
-    set(package_repo "ext-android-bin/raw/master/")
-    set(package_extension ".tar.xz")
-else()
-    message(FATAL_ERROR "No package available for this platform")
-endif()
-set(package_url "${package_base_url}${package_repo}")
-
-set(prefix "${CMAKE_BINARY_DIR}/externals/${lib_name}")
-if (NOT EXISTS "${prefix}")
-    message(STATUS "Downloading binaries for ${lib_name}...")
-    file(DOWNLOAD
-        ${package_url}${remote_path}${lib_name}${package_extension}
-        "${CMAKE_BINARY_DIR}/externals/${lib_name}${package_extension}" SHOW_PROGRESS)
-    execute_process(COMMAND ${CMAKE_COMMAND} -E tar xf "${CMAKE_BINARY_DIR}/externals/${lib_name}${package_extension}"
-        WORKING_DIRECTORY "${CMAKE_BINARY_DIR}/externals")
-endif()
-message(STATUS "Using bundled binaries at ${prefix}")
-set(${prefix_var} "${prefix}" PARENT_SCOPE)
+function(download_bundled_external remote_path lib_name cpm_key prefix_var)
+    set(package_base_url "https://github.com/eden-emulator/")
+    set(package_repo "no_platform")
+    set(package_extension "no_platform")
+
+    if (WIN32 OR FORCE_WIN_ARCHIVES)
+        set(CACHE_KEY "windows")
+        set(package_repo "ext-windows-bin/raw/master/")
+        set(package_extension ".7z")
+    elseif (${CMAKE_SYSTEM_NAME} STREQUAL "Linux")
+        set(CACHE_KEY "linux")
+        set(package_repo "ext-linux-bin/raw/master/")
+        set(package_extension ".tar.xz")
+    elseif (ANDROID)
+        set(CACHE_KEY "android")
+        set(package_repo "ext-android-bin/raw/master/")
+        set(package_extension ".tar.xz")
+    else()
+        message(FATAL_ERROR "No package available for this platform")
+    endif()
+    set(package_url "${package_base_url}${package_repo}")
+    set(full_url ${package_url}${remote_path}${lib_name}${package_extension})
+
+    set(CPM_USE_LOCAL_PACKAGES OFF)
+
+    CPMAddPackage(
+        NAME ${cpm_key}
+        URL ${full_url}
+        DOWNLOAD_ONLY YES
+        CUSTOM_CACHE_KEY ${CACHE_KEY}
+    )
+
+    set(${prefix_var} "${${cpm_key}_SOURCE_DIR}" PARENT_SCOPE)
+    message(STATUS "Using bundled binaries at ${${cpm_key}_SOURCE_DIR}")
+endfunction()
+
+function(download_win_archives)
+    set(FORCE_WIN_ARCHIVES ON)
+    set(FFmpeg_EXT_NAME "ffmpeg-7.1.1")
+
+    download_bundled_external("ffmpeg/" ${FFmpeg_EXT_NAME} "ffmpeg-bundled" "")
+
+    # TODO(crueter): separate handling for arm64
+    set(SDL2_VER "SDL2-2.32.8")
+    download_bundled_external("sdl2/" ${SDL2_VER} "sdl2-bundled" "")
+    set(FORCE_WIN_ARCHIVES OFF)
 endfunction()
 
 function(download_moltenvk_external platform version)