Add automatic generation of version and build type headers for compilation

This change replaces the static version and build type header file generation
by CMake with dynamic CMake targets to generate the version file whenever a Make
target is executed. Thus, there is no need anymore to reconfigure and rerun
CMake after the repository version or build configuration has changed.

1 files changed, 80 insertions, 0 deletions

diff --git a/cmake/Version.cmake b/cmake/Version.cmake
new file mode 100644
index 0000000..a061e48
--- /dev/null
+++ b/cmake/Version.cmake
@@ -0,0 +1,80 @@
+# SPDX-License-Identifier: GPL-2.0
+#
+# Copyright (C) 2020 Manuel Bentele <development@manuel-bentele.de>
+#
+
+macro(gen_project_version VERSION_INPUT_FILE VERSION_INPUT_FILE_TEMPLATE VERSION_OUTPUT_FILE)
+    get_filename_component(VERSION_OUTPUT_FILENAME ${VERSION_OUTPUT_FILE} NAME)
+    # command that will trigger a rebuild of version.h every time
+    add_custom_command(OUTPUT regenerate-version-file
+                       COMMAND ${CMAKE_COMMAND} -E sleep 0
+                       COMMENT "Trigger generating ${VERSION_OUTPUT_FILENAME}")
+
+    # call the GenerateVersion.cmake file to generate the version.c file
+    add_custom_command(OUTPUT ${VERSION_OUTPUT_FILE}
+                       COMMAND ${CMAKE_COMMAND} -D VERSION_MODULE_PATH=${PROJECT_MODULES_DIR}
+                                                -D VERSION_INPUT_FILE=${VERSION_INPUT_FILE}
+                                                -D VERSION_INPUT_FILE_TEMPLATE=${VERSION_INPUT_FILE_TEMPLATE}
+                                                -D VERSION_OUTPUT_FILE=${VERSION_OUTPUT_FILE}
+                                                -D VERSION_BUILD_TYPE=${CMAKE_BUILD_TYPE}
+                                                -P ${PROJECT_MODULES_DIR}/GenerateVersion.cmake
+                       COMMENT "Generating ${VERSION_OUTPUT_FILENAME}"
+                       DEPENDS regenerate-version-file)
+    add_custom_target(xloop-generate-version DEPENDS ${VERSION_OUTPUT_FILE})
+
+    # create target to expose project version
+    add_library(xloop-version INTERFACE)
+    target_include_directories(xloop-version INTERFACE ${PROJECT_INCLUDE_GEN_DIR})
+    add_dependencies(xloop-version xloop-generate-version)
+endmacro(gen_project_version VERSION_INPUT_FILE VERSION_INPUT_FILE_TEMPLATE VERSION_OUTPUT_FILE)
+
+# macro to get Linux kernel version from KERNEL_BUILD_DIR string
+macro(get_kernel_version LINUX_KERNEL_VERSION KERNEL_BUILD_DIR)
+    string(REGEX MATCH "[0-9]+\\.[0-9]+\\.[0-9]+" LINUX_KERNEL_VERSION ${KERNEL_BUILD_DIR})
+    if(LINUX_KERNEL_VERSION STREQUAL "")
+        set(LINUX_KERNEL_VERSION "unknown")
+    endif(LINUX_KERNEL_VERSION STREQUAL "")
+endmacro(get_kernel_version LINUX_KERNEL_VERSION KERNEL_BUILD_DIR)
+
+# macro to get Git version information
+macro(get_repository_version REPOSITORY_VERSION VERSION_HEADER_FILE VERSION_BUILD_TYPE)
+    # check if generated version header from source package is available
+    if(EXISTS ${VERSION_HEADER_FILE})
+        # get version information from the generated version header of the source package
+        file(READ ${VERSION_HEADER_FILE} GIT_VERSION)
+        string(REGEX MATCH "\"(([0-9]+:)?[0-9][A-Za-z0-9.+~-]*)\"" GIT_VERSION ${GIT_VERSION})
+        set(GIT_VERSION "${CMAKE_MATCH_1}")
+    else(EXISTS ${VERSION_HEADER_FILE})
+        # get detailed Git version information from Git repository
+        execute_process(COMMAND git describe HEAD
+                        OUTPUT_VARIABLE GIT_VERSION
+                        OUTPUT_STRIP_TRAILING_WHITESPACE)
+
+        # remove the first letter of the version to satisfy packaging rules
+        string(REGEX MATCH "([0-9]+:)?[0-9][A-Za-z0-9.+~-]*" GIT_VERSION ${GIT_VERSION})
+
+        # overwrite version from Git if version is unknown
+        if(GIT_VERSION STREQUAL "")
+            set(GIT_VERSION "unknown")
+        endif(GIT_VERSION STREQUAL "")
+
+        # get status of Git repository
+        execute_process(COMMAND git status --porcelain
+                        OUTPUT_VARIABLE GIT_STATUS
+                        OUTPUT_STRIP_TRAILING_WHITESPACE)
+
+        # check if Git repository is dirty
+        if(NOT GIT_STATUS STREQUAL "")
+            # the Git repository is dirty, thus extend the version information
+            set(GIT_VERSION "${GIT_VERSION}-modified")
+
+            # print a message in Release build configuration to warn about the dirty repository
+            if(${VERSION_BUILD_TYPE} MATCHES "Release")
+                message(WARNING "This xloop Git repository is dirty! Please commit or revert all changes for a ${VERSION_BUILD_TYPE} build!")
+            endif(${VERSION_BUILD_TYPE} MATCHES "Release")
+        endif(NOT GIT_STATUS STREQUAL "")
+    endif(EXISTS ${VERSION_HEADER_FILE})
+
+    # return version to caller
+    set(${REPOSITORY_VERSION} ${GIT_VERSION})
+endmacro(get_repository_version)