Install receipt with SHA256 checksums

 - This will be great for making it easier to:
   - Uninstall the package, ensuring that the files are not custom modifications
   - Verify reproducible builds

Author: zbeekman

CMakeLists.txt

@@ -2,6 +2,10 @@ cmake_minimum_required(VERSION 3.10)
 
 cmake_policy(VERSION 3.10...3.14)
 
+if(DEFINED ENV{SOURCE_DATE_EPOCH})
+  set(SOURCE_DATE_EPOCH "$ENV{SOURCE_DATE_EPOCH}")
+endif()
+
 set(CMAKE_SKIP_RPATH ON
   CACHE BOOL "Don't add a build-dir rpath")
 set(CMAKE_BUILD_WITH_INSTALL_RPATH ON
@@ -941,6 +945,8 @@ foreach(SCRIPT ${TRAVIS_SCRIPTS})
   endif()
 endforeach()
 
-install(FILES "${CMAKE_BINARY_DIR}/sha256_install_manifest.txt"
-  DESTINATION "${CMAKE_INSTALL_DATADIR}/opencoarrays"
-  OPTIONAL)
+# Create and install a manifest of installed files, and another containing their sha256 hashes
+foreach(VAR CMAKE_BINARY_DIR CMAKE_INSTALL_DATADIR PROJECT_NAME SOURCE_DATE_EPOCH)
+  install(CODE "set(${VAR} \"${${VAR}}\")")
+endforeach()
+install(SCRIPT "${CMAKE_CURRENT_LIST_DIR}/cmake/InstallFileManifest.cmake")

cmake/InstallFileManifest.cmake

@@ -0,0 +1,29 @@
+# This script will create and install an install manifest, including SHA256 hashes of each installed file
+# Variables passed from CMake must be set with `install(CODE "set(...)")`
+
+message(STATUS "Generating SHA256 checksums for all installed assets")
+
+# Mimic cmake_install.cmake's handlin of components
+if(CMAKE_INSTALL_COMPONENT)
+  set(HASHED_INSTALL_MANIFEST "install_manifest_${CMAKE_INSTALL_COMPONENT}.SHA256.txt")
+else()
+  set(HASHED_INSTALL_MANIFEST "install_manifest.SHA256.txt")
+endif()
+
+# Clean out any old install manifest on re-installation, if it exists
+file(REMOVE "${CMAKE_BINARY_DIR}/${HASHED_INSTALL_MANIFEST}")
+
+# Loop over files computing hashes
+foreach(file IN LISTS CMAKE_INSTALL_MANIFEST_FILES)
+  file(SHA256 "${file}" _file_sha256)
+  file(APPEND "${CMAKE_BINARY_DIR}/${HASHED_INSTALL_MANIFEST}" "${_file_sha256}  ${file}\n")
+endforeach()
+
+file(INSTALL DESTINATION "${CMAKE_INSTALL_PREFIX}/${CMAKE_INSTALL_DATADIR}/${PROJECT_NAME}" TYPE FILE PERMISSIONS OWNER_READ OWNER_WRITE GROUP_READ WORLD_READ FILES
+  "${CMAKE_BINARY_DIR}/${HASHED_INSTALL_MANIFEST}")
+
+file(SHA256 "${CMAKE_BINARY_DIR}/${HASHED_INSTALL_MANIFEST}" MANIFEST_SHA256)
+message(STATUS
+  "Global checksum for OpenCoarrays installation:\n${MANIFEST_SHA256}  ${HASHED_INSTALL_MANIFEST}")
+message(STATUS "${PROJECT_NAME} was configured with SOURCE_DATE_EPOCH=${SOURCE_DATE_EPOCH}")
+message(STATUS "The current environment has SOURCE_DATE_EPOCH set to: $ENV{SOURCE_DATE_EPOCH}")