add Git tracability example in CMake (TODO: Meson)

Author: scivision

CMakeLists.txt

@@ -23,6 +23,7 @@ add_subdirectory(block)
 add_subdirectory(character)
 add_subdirectory(coarray)
 add_subdirectory(contiguous)
+add_subdirectory(git)
 add_subdirectory(io)
 add_subdirectory(debug)
 add_subdirectory(lapack95)

git/CMakeLists.txt

@@ -0,0 +1,24 @@
+find_package(Git)
+
+set(git_version ${GIT_VERSION_STRING})
+if(GIT_FOUND)
+# git branch --show-current requires Git >= 2.22, June 2019
+execute_process(COMMAND ${GIT_EXECUTABLE} rev-parse --abbrev-ref HEAD
+OUTPUT_VARIABLE git_branch OUTPUT_STRIP_TRAILING_WHITESPACE)
+execute_process(COMMAND ${GIT_EXECUTABLE} rev-parse --short HEAD
+OUTPUT_VARIABLE git_rev OUTPUT_STRIP_TRAILING_WHITESPACE)
+execute_process(COMMAND ${GIT_EXECUTABLE} status --porcelain
+OUTPUT_VARIABLE git_porcelain OUTPUT_STRIP_TRAILING_WHITESPACE)
+string(REGEX REPLACE "\n" " " git_porcelain ${git_porcelain})
+else()
+set(git_branch)
+set(git_rev)
+set(git_porcelain)
+endif()
+
+message(STATUS "${PROJECT_NAME}  git revision: ${git_rev}  git_branch: ${git_branch}  git_porcelain: ${git_porcelain}")
+
+# example
+configure_file(main.in.f90 main.f90)
+add_executable(git_rev ${CMAKE_CURRENT_BINARY_DIR}/main.f90)
+add_test(NAME git:revision COMMAND $<TARGET_FILE:git_rev>)

git/main.in.f90

@@ -0,0 +1,17 @@
+program git_demo
+
+implicit none (type, external)
+
+character(:), allocatable :: git_version, branch, rev, porcelain
+
+git_version = "@git_version@"
+branch = "@git_branch@"
+rev = "@git_rev@"
+porcelain = "@git_porcelain@"
+
+print *, "MyProgram  git_version:", git_version, " git_branch: ", branch, " git revision: ", rev
+
+if (len(porcelain) > 0) print *, " git_porcelain:", porcelain
+!! could also use this to set a warning or other logical flag
+
+end program