Use only Git commands in git_info

modules/git_info/git_info.cmake

@@ -5,22 +5,66 @@
 # Git repository version and status information
 # to the program output.
 #
-# autocmake.cfg configuration::
+# autocmake.yml configuration::
 #
-#   fetch: https://github.com/scisoft/autocmake/raw/master/modules/git_info/git_info_sub.cmake
-#          https://github.com/scisoft/autocmake/raw/master/modules/git_info/git_info.h.in
+#   url_root: https://github.com/coderefinery/autocmake/raw/master/
+#   fetch:
+#     - "%(url_root)modules/git_info/git_info_sub.cmake"
+#     - "%(url_root)modules/git_info/git_info.h.in"
 
-# CMAKE_CURRENT_LIST_DIR is undefined in CMake 2.8.2
-# see https://public.kitware.com/Bug/print_bug_page.php?bug_id=11675
-# workaround: create CMAKE_CURRENT_LIST_DIR 
-get_filename_component(CMAKE_CURRENT_LIST_DIR ${CMAKE_CURRENT_LIST_FILE} PATH)
-add_custom_command(
-    OUTPUT ${PROJECT_BINARY_DIR}/git_info.h
-    COMMAND ${CMAKE_COMMAND} -D_target_dir=${PROJECT_BINARY_DIR} -P git_info_sub.cmake
-    WORKING_DIRECTORY ${CMAKE_CURRENT_LIST_DIR}
+# _header_location: where the Git info header file should be generated
+# _header_name: the Git info header name, complete with extension (.h, .hpp, .hxx or whatever)
+function(generate_git_info_header _header_location _header_name)
+  find_package(Git)
+
+  set(_git_last_commit_hash "unknown")
+  set(_git_last_commit_author "unknown")
+  set(_git_last_commit_date "unknown")
+  set(_git_branch "unknown")
+
+  if(GIT_FOUND)
+    execute_process(
+      COMMAND ${GIT_EXECUTABLE} --no-pager show -s --pretty=format:%h -n 1
+      OUTPUT_VARIABLE _git_last_commit_hash
+      OUTPUT_STRIP_TRAILING_WHITESPACE
+      ERROR_QUIET
+      )
+
+    execute_process(
+      COMMAND ${GIT_EXECUTABLE} --no-pager show -s --pretty=format:%aN -n 1
+      OUTPUT_VARIABLE _git_last_commit_author
+      OUTPUT_STRIP_TRAILING_WHITESPACE
+      ERROR_QUIET
+      )
+
+    execute_process(
+      COMMAND ${GIT_EXECUTABLE} --no-pager show -s --pretty=format:%ad -n 1
+      OUTPUT_VARIABLE _git_last_commit_date
+      OUTPUT_STRIP_TRAILING_WHITESPACE
+      ERROR_QUIET
+      )
+
+    execute_process(
+      COMMAND ${GIT_EXECUTABLE} rev-parse --abbrev-ref HEAD
+      OUTPUT_VARIABLE _git_branch
+      OUTPUT_STRIP_TRAILING_WHITESPACE
+      ERROR_QUIET
+      )
+  endif()
+
+  configure_file(
+    ${PROJECT_SOURCE_DIR}/cmake/downloaded/git_info.h.in
+    ${_header_location}/${_header_name}
+    @ONLY
     )
 
-add_custom_target(
+  unset(_git_last_commit_hash)
+  unset(_git_last_commit_author)
+  unset(_git_last_commit_date)
+  unset(_git_branch)
+
+  add_custom_target(
     git_info
-    ALL DEPENDS ${PROJECT_BINARY_DIR}/git_info.h
+    ALL DEPENDS ${_header_location}/${_header_name}
     )
+endfunction()