cmake: Find a directory that could be used to cache files

To improve the build system's "clean build" runtime we need to cache
files in a directory outside of the build directory.

Caching files outside of the build directory is is already being done
to a certain degree today. For instance, if a user has installed
ccache it will cache files in $HOME/.ccache/.

This commit locates a directory that is suitable for caching files in
a cross-platform way. For instance on Linux this is believed to be
$HOME, on Windows this is believed to be %LOCALAPPDATA%.

If for whatever reason no environment variables are are found to be
suitable we fall back to using $ZEPHYR_BASE/.cache/. For users that
often use 'git -clean' the caching mechanism will not work as well,
but it will at least be better than no caching at all.

Signed-off-by: Sebastian Bøe <sebastian.boe@nordicsemi.no>
This commit is contained in:
Sebastian Bøe 2018-04-16 18:55:23 +02:00 committed by Carles Cufí
parent 6c3a94c01f
commit 709daa20e9
3 changed files with 67 additions and 0 deletions

5
.gitignore vendored
View file

@ -11,6 +11,11 @@ build
build-*
cscope.*
.dir
# The .cache directory will be used to cache toolchain capabilities if
# no suitable out-of-tree directory is found.
.cache
outdir
outdir-*
scripts/basic/fixdep

View file

@ -274,6 +274,13 @@ set(KERNEL_EXE_NAME ${KERNEL_NAME}.exe)
set(KERNEL_STAT_NAME ${KERNEL_NAME}.stat)
set(KERNEL_STRIP_NAME ${KERNEL_NAME}.strip)
# Populate USER_CACHE_DIR with a directory that user applications may
# write cache files to.
if(NOT DEFINED USER_CACHE_DIR)
find_appropriate_cache_directory(USER_CACHE_DIR)
endif()
message(STATUS "Cache files will be written to: ${USER_CACHE_DIR}")
include(${BOARD_DIR}/board.cmake OPTIONAL)
zephyr_library_named(app)

View file

@ -1023,3 +1023,58 @@ function(check_if_directory_is_writeable dir ok)
endif()
endfunction()
function(find_appropriate_cache_directory dir)
set(env_suffix_LOCALAPPDATA .cache)
if(CMAKE_HOST_APPLE)
# On macOS, ~/Library/Caches is the preferred cache directory.
set(env_suffix_HOME Library/Caches)
else()
set(env_suffix_HOME .cache)
endif()
# Determine which env vars should be checked
if(CMAKE_HOST_APPLE)
set(dirs HOME)
elseif(CMAKE_HOST_WIN32)
set(dirs LOCALAPPDATA)
else()
# Assume Linux when we did not detect 'mac' or 'win'
#
# On Linux, freedesktop.org recommends using $XDG_CACHE_HOME if
# that is defined and defaulting to $HOME/.cache otherwise.
set(dirs
XDG_CACHE_HOME
HOME
)
endif()
foreach(env_var ${dirs})
if(DEFINED ENV{${env_var}})
set(env_dir $ENV{${env_var}})
check_if_directory_is_writeable(${env_dir} ok)
if(${ok})
# The directory is write-able
set(user_dir ${env_dir}/${env_suffix_${env_var}})
break()
else()
# The directory was not writeable, keep looking for a suitable
# directory
endif()
endif()
endforeach()
# Populate local_dir with a suitable directory for caching
# files. Prefer a directory outside of the git repository because it
# is good practice to have clean git repositories.
if(DEFINED user_dir)
# Zephyr's cache files go in the "zephyr" subdirectory of the
# user's cache directory.
set(local_dir ${user_dir}/zephyr)
else()
set(local_dir ${ZEPHYR_BASE}/.cache)
endif()
set(${dir} ${local_dir} PARENT_SCOPE)
endfunction()