From 52501b7b6532a427a19c7ee619bd2552580398ae Mon Sep 17 00:00:00 2001
From: Andrew Dunn <Andrew-Dunn@users.noreply.github.com>
Date: Sat, 17 Sep 2022 18:24:06 +1000
Subject: [PATCH] Re-sign Mac Applications before creating install package

On Apple Silicon, the changes to linking paths done to "relativise"
paths in App bundles invalidates the code signature, so we need to
recalculate the signatures *after* the path changes have been performed
but before the install package is created. This depends on a new CMake
feature introduced in 3.19.
---
 CMakeLists.txt                  |  5 ++++-
 cmake/SignMacApplications.cmake | 20 ++++++++++++++++++++
 2 files changed, 24 insertions(+), 1 deletion(-)
 create mode 100644 cmake/SignMacApplications.cmake

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 5d58ad43af..e4aff6fdd5 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -1,4 +1,4 @@
-cmake_minimum_required(VERSION 3.1.0)
+cmake_minimum_required(VERSION 3.19.0)
 
 # for link time optimization, remove if cmake version is >= 3.9
 if(POLICY CMP0069) # LTO
@@ -888,6 +888,9 @@ if (OPENMW_OSX_DEPLOYMENT AND APPLE)
         fixup_bundle(\"${INSTALLED_OPENMW_APP}\" \"${PLUGINS}\" \"\")
         fixup_bundle(\"${INSTALLED_OPENCS_APP}\" \"${OPENCS_PLUGINS}\" \"\")
         " COMPONENT Runtime)
+
+    set(CPACK_PRE_BUILD_SCRIPTS ${CMAKE_SOURCE_DIR}/cmake/SignMacApplications.cmake)
+
     include(CPack)
 elseif(NOT APPLE)
     get_generator_is_multi_config(multi_config)
diff --git a/cmake/SignMacApplications.cmake b/cmake/SignMacApplications.cmake
new file mode 100644
index 0000000000..aa1b6ed17f
--- /dev/null
+++ b/cmake/SignMacApplications.cmake
@@ -0,0 +1,20 @@
+# This script re-signs OpenMW.app and OpenMW-CS.app after CPack packages them. This is necessary because CPack modifies
+# the library references used by OpenMW to App relative paths, invalidating the code signature.
+
+# Obviously, we only need to run this on Apple targets.
+if (APPLE)
+    set(OPENMW_APP "OpenMW")
+    set(OPENMW_CS_APP "OpenMW-CS")
+
+    set(APPLICATIONS "${OPENMW_APP}" "${OPENMW_CS_APP}")
+    foreach(app_name IN LISTS APPLICATIONS)
+        set(FULL_APP_PATH "${CPACK_TEMPORARY_INSTALL_DIRECTORY}/ALL_IN_ONE/${app_name}.app")
+        message(STATUS "Re-signing ${app_name}.app")
+        # Apple's codesign utility does not like directories with periods (.) in their names, so we'll remove it and
+        # create a symlink using the original name, which codesign is fine with.
+        file(GLOB OSG_PLUGINS_DIR "${FULL_APP_PATH}/Contents/PlugIns/osgPlugins*")
+        file(RENAME "${OSG_PLUGINS_DIR}" "${FULL_APP_PATH}/Contents/PlugIns/osgPlugins")
+        execute_process(COMMAND "ln" "-s" "${FULL_APP_PATH}/Contents/PlugIns/osgPlugins" "${OSG_PLUGINS_DIR}")
+        execute_process(COMMAND "codesign" "--force" "--deep" "-s" "-" "${FULL_APP_PATH}")
+    endforeach(app_name)
+endif (APPLE)
\ No newline at end of file