diff options
Diffstat (limited to 'cmake')
| -rw-r--r-- | cmake/git_watcher.cmake | 213 |
1 files changed, 213 insertions, 0 deletions
diff --git a/cmake/git_watcher.cmake b/cmake/git_watcher.cmake new file mode 100644 index 0000000..6447b86 --- /dev/null +++ b/cmake/git_watcher.cmake @@ -0,0 +1,213 @@ +# git_watcher.cmake +# +# License: MIT +# Source: https://raw.githubusercontent.com/andrew-hardin/cmake-git-version-tracking/master/git_watcher.cmake + + +# This file defines the functions and targets needed to monitor +# the state of a git repo. If the state changes (e.g. a commit is made), +# then a file gets reconfigured. +# +# The behavior of this script can be modified by defining any of these variables: +# +# PRE_CONFIGURE_GIT_VERSION_FILE (REQUIRED) +# -- The path to the file that'll be configured. +# +# POST_CONFIGURE_GIT_VERSION_FILE (REQUIRED) +# -- The path to the configured PRE_CONFIGURE_GIT_VERSION_FILE. +# +# GIT_STATE_FILE (OPTIONAL) +# -- The path to the file used to store the previous build's git state. +# Defaults to the current binary directory. +# +# GIT_WORKING_DIR (OPTIONAL) +# -- The directory from which git commands will be run. +# Defaults to the directory with the top level CMakeLists.txt. +# +# GIT_EXECUTABLE (OPTIONAL) +# -- The path to the git executable. It'll automatically be set if the +# user doesn't supply a path. +# +# Script design: +# - This script was designed similar to a Python application +# with a Main() function. I wanted to keep it compact to +# simplify "copy + paste" usage. +# +# - This script is made to operate in two CMake contexts: +# 1. Configure time context (when build files are created). +# 2. Build time context (called via CMake -P) +# If you see something odd (e.g. the NOT DEFINED clauses), +# consider that it can run in one of two contexts. + +# Short hand for converting paths to absolute. +macro(PATH_TO_ABSOLUTE var_name) + get_filename_component(${var_name} "${${var_name}}" ABSOLUTE) +endmacro() + +# Check that a required variable is set. +macro(CHECK_REQUIRED_VARIABLE var_name) + if(NOT DEFINED ${var_name}) + message(FATAL_ERROR "The \"${var_name}\" variable must be defined.") + endif() + PATH_TO_ABSOLUTE(${var_name}) +endmacro() + +# Check that an optional variable is set, or, set it to a default value. +macro(CHECK_OPTIONAL_VARIABLE var_name default_value) + if(NOT DEFINED ${var_name}) + set(${var_name} ${default_value}) + endif() + PATH_TO_ABSOLUTE(${var_name}) +endmacro() + +CHECK_REQUIRED_VARIABLE(PRE_CONFIGURE_GIT_VERSION_FILE) +CHECK_REQUIRED_VARIABLE(POST_CONFIGURE_GIT_VERSION_FILE) +CHECK_OPTIONAL_VARIABLE(GIT_STATE_FILE "${GENERATED_SRC}/git_state") +#CHECK_REQUIRED_VARIABLE(GIT_STATE_FILE) +CHECK_OPTIONAL_VARIABLE(GIT_WORKING_DIR "${CMAKE_SOURCE_DIR}") + +# Check the optional git variable. +# If it's not set, we'll try to find it using the CMake packaging system. +if(NOT DEFINED GIT_EXECUTABLE) + find_package(Git QUIET REQUIRED) +endif() +CHECK_REQUIRED_VARIABLE(GIT_EXECUTABLE) + + + +# Function: GitStateChangedAction +# Description: this function is executed when the state of the git +# repo changes (e.g. a commit is made). +function(GitStateChangedAction _state_as_list) + # Set variables by index, then configure the file w/ these variables defined. + LIST(GET _state_as_list 0 GIT_RETRIEVED_STATE) + LIST(GET _state_as_list 1 GIT_HEAD_SHA1) + LIST(GET _state_as_list 2 GIT_IS_DIRTY) + configure_file("${PRE_CONFIGURE_GIT_VERSION_FILE}" "${POST_CONFIGURE_GIT_VERSION_FILE}" @ONLY) +endfunction() + + + +# Function: GetGitState +# Description: gets the current state of the git repo. +# Args: +# _working_dir (in) string; the directory from which git commands will be executed. +# _state (out) list; a collection of variables representing the state of the +# repository (e.g. commit SHA). +function(GetGitState _working_dir _state) + + # Get the hash for HEAD. + set(_success "true") + execute_process(COMMAND + "${GIT_EXECUTABLE}" rev-parse --verify HEAD + WORKING_DIRECTORY "${_working_dir}" + RESULT_VARIABLE res + OUTPUT_VARIABLE _hashvar + ERROR_QUIET + OUTPUT_STRIP_TRAILING_WHITESPACE) + if(NOT res EQUAL 0) + set(_success "false") + set(_hashvar "GIT-NOTFOUND") + endif() + + # Get whether or not the working tree is dirty. + execute_process(COMMAND + "${GIT_EXECUTABLE}" status --porcelain + WORKING_DIRECTORY "${_working_dir}" + RESULT_VARIABLE res + OUTPUT_VARIABLE out + ERROR_QUIET + OUTPUT_STRIP_TRAILING_WHITESPACE) + if(NOT res EQUAL 0) + set(_success "false") + set(_dirty "false") + else() + if(NOT "${out}" STREQUAL "") + set(_dirty "true") + else() + set(_dirty "false") + endif() + endif() + + # Return a list of our variables to the parent scope. + set(${_state} ${_success} ${_hashvar} ${_dirty} PARENT_SCOPE) +endfunction() + + + +# Function: CheckGit +# Description: check if the git repo has changed. If so, update the state file. +# Args: +# _working_dir (in) string; the directory from which git commands will be ran. +# _state_changed (out) bool; whether or no the state of the repo has changed. +# _state (out) list; the repository state as a list (e.g. commit SHA). +function(CheckGit _working_dir _state_changed _state) + + # Get the current state of the repo. + GetGitState("${_working_dir}" state) + + # Set the output _state variable. + # (Passing by reference in CMake is awkward...) + set(${_state} ${state} PARENT_SCOPE) + + # Check if the state has changed compared to the backup on disk. + if(EXISTS "${GIT_STATE_FILE}") + file(READ "${GIT_STATE_FILE}" OLD_HEAD_CONTENTS) + if(OLD_HEAD_CONTENTS STREQUAL "${state}") + # State didn't change. + set(${_state_changed} "false" PARENT_SCOPE) + return() + endif() + endif() + + # The state has changed. + # We need to update the state file on disk. + # Future builds will compare their state to this file. + file(WRITE "${GIT_STATE_FILE}" "${state}") + set(${_state_changed} "true" PARENT_SCOPE) +endfunction() + + + +# Function: SetupGitMonitoring +# Description: this function sets up custom commands that make the build system +# check the state of git before every build. If the state has +# changed, then a file is configured. +function(SetupGitMonitoring) + add_custom_target(check_git_repository + ALL + DEPENDS ${PRE_CONFIGURE_GIT_VERSION_FILE} + BYPRODUCTS ${POST_CONFIGURE_GIT_VERSION_FILE} + COMMENT "Checking the git repository for changes..." + COMMAND + ${CMAKE_COMMAND} + -D_BUILD_TIME_CHECK_GIT=TRUE + -DGIT_WORKING_DIR=${GIT_WORKING_DIR} + -DGIT_EXECUTABLE=${GIT_EXECUTABLE} + -DGIT_STATE_FILE=${GIT_STATE_FILE} + -DPRE_CONFIGURE_GIT_VERSION_FILE=${PRE_CONFIGURE_GIT_VERSION_FILE} + -DPOST_CONFIGURE_GIT_VERSION_FILE=${POST_CONFIGURE_GIT_VERSION_FILE} + -P "${CMAKE_CURRENT_LIST_FILE}") +endfunction() + + + +# Function: Main +# Description: primary entry-point to the script. Functions are selected based +# on whether it's configure or build time. +function(Main) + if(_BUILD_TIME_CHECK_GIT) + # Check if the repo has changed. + # If so, run the change action. + CheckGit("${GIT_WORKING_DIR}" did_change state) + if(did_change) + GitStateChangedAction("${state}") + endif() + else() + # >> Executes at configure time. + SetupGitMonitoring() + endif() +endfunction() + +# And off we go... +Main() |