How to call a custom cmake script only when files are updated? - cmake

I want to run an JavaScript minifier only when my JavaScript files are updated.
I know how to do this in make, but not in CMakelist.
Currently I have a script that minifies the JavaScript files, but it runs any time any files update.
add_custom_target(MINI-JS ALL DEPENDS ${JS_FILES}
COMMAND rm -f ../projectv/js/all-min.js
COMMAND cat ${JS_FILES} | jsmin >> ../projectv/js/all-min.js
)
Edit: Tsyvarev's comment seems to suggest this:
add_custom_command(OUTPUT ../projectv/js/all-min.js
DEPENDS ${JS_FILES}
COMMAND rm -f ../projectv/js/all-min.js
COMMAND cat ${JS_FILES} | jsmin >> ../projectv/js/all-min.js
)
add_custom_target(MINI-JS ALL DEPENDS ../projectv/js/all-min.js)
This never updates, even when the JavaScript files change. Am I missing something?

The code below should work. In my example I'm using CMake command line tool -E mode. This way the custom command is more portable. My example relies on 3.17 though.
# SUPER IMPORTANT: Always specify absolute paths!
set(foobar "${CMAKE_CURRENT_LIST_DIR}../projectv/js/all-min.js")
add_custom_command(
OUTPUT
# This is the file your custom command will create
${foobar}
DEPENDS
# These are all the files you need to run your custom command
${JS_FILES}
COMMAND
COMMAND ${CMAKE_COMMAND} -E rm ${foobar}
COMMAND ${CMAKE_COMMAND} -E cat ${JS_FILES} | jsmin >> ${foobar}
)
add_custom_target(MINI-JS ALL DEPENDS ${foobar})

Related

Force custom command to always run without first deleting the output

I have a setup where I use a custom command to check the current hash of a git repository so that other commands can clone it if it has updated
add_custom_command(
OUTPUT ${CMAKE_CURRENT_BINARY_DIR}/module_VERSION.txt
COMMAND ${GIT_EXECUTABLE} ls-remote ${MODULE_URL} master > ${CMAKE_CURRENT_BINARY_DIR}/module_VERSION.txt.tmp
COMMAND ${CMAKE_COMMAND} -E copy_if_different ${CMAKE_CURRENT_BINARY_DIR}/module_VERSION.txt.tmp ${CMAKE_CURRENT_BINARY_DIR}/module_VERSION.txt
COMMAND ${CMAKE_COMMAND} -E rm ${CMAKE_CURRENT_BINARY_DIR}/module_VERSION.txt.tmp
)
Of course this will only run once as CMake sees no reason to rerun it. I can force it to run by adding a second (dummy) output - CMake then recognises that this output doesn't exist and then reruns the rule. However the Makefile that this generates actually deletes module_VERSION.txt before running the command rendering the whole pursuit pointless (Ninja does not have this problem).
I am able to get this to work but in an extremely hacky way: creating another target that always runs and then generating a dependency on this.
# Use echo_append as a no-op
add_custom_command(
OUTPUT module_FORCERUN
COMMAND ${CMAKE_COMMAND} -E echo_append
)
add_custom_command(
OUTPUT ${CMAKE_CURRENT_BINARY_DIR}/module_VERSION.txt
COMMAND ${GIT_EXECUTABLE} ls-remote ${MODULE_URL} master > ${CMAKE_CURRENT_BINARY_DIR}/module_VERSION.txt.tmp
COMMAND ${CMAKE_COMMAND} -E copy_if_different ${CMAKE_CURRENT_BINARY_DIR}/module_VERSION.txt.tmp ${CMAKE_CURRENT_BINARY_DIR}/module_VERSION.txt
COMMAND ${CMAKE_COMMAND} -E rm ${CMAKE_CURRENT_BINARY_DIR}/module_VERSION.txt.tmp
DEPENDS module_FORCERUN
)
This seems just really hacky and like it could be relying on some corner cases in cmake which aren't guaranteed to be stable. Is there a better way to get this working?
I am using cmake 3.21.3
Use add_custom_target for implement "always run" functionality and via BYPRODUCTS keyword specify the file which it could produce/update:
add_custom_target(update_module_version
BYPRODUCTS ${CMAKE_CURRENT_BINARY_DIR}/module_VERSION.txt
COMMAND ${GIT_EXECUTABLE} ls-remote ${MODULE_URL} master > ${CMAKE_CURRENT_BINARY_DIR}/module_VERSION.txt.tmp
COMMAND ${CMAKE_COMMAND} -E copy_if_different ${CMAKE_CURRENT_BINARY_DIR}/module_VERSION.txt.tmp ${CMAKE_CURRENT_BINARY_DIR}/module_VERSION.txt
COMMAND ${CMAKE_COMMAND} -E rm ${CMAKE_CURRENT_BINARY_DIR}/module_VERSION.txt.tmp
)
That way, if any other target will depend on update_module_version one, the module_VERSION.txt file will be created/updated before evaluation of the target.
Such target-level dependency will be created automatically by CMake, if given file will be listed as dependency for target/command in the same directory, where target update_module_version is created:
add_custom_command(OUTPUT <...>
DEPENDS ${CMAKE_CURRENT_BINARY_DIR}/module_VERSION.txt
COMMAND <...>
)
From other directories the target-level dependency should be specified explicitly:
# If used in other directories
add_custom_command(OUTPUT <...>
DEPENDS ${CMAKE_CURRENT_BINARY_DIR}/module_VERSION.txt
update_module_version
COMMAND <...>
)

CMake add_custom_command: How to write a "quoted string" to a file?

I have spent way too much time trying to add a custom command that writes a "quoted string" to a file:
add_custom_command(
OUTPUT file
COMMAND ${CMAKE_COMMAND} -E echo "\"quoted string\"" > file
...
DEPENDS something
VERBATIM (?)
)
I have tried various ways to escape the quotes \", \\", \\\", quoting the whole command, putting the command in variable, but none of them worked. How can this be achieved?
The following works on both Windows(Ninja) and WSL(unix makefiles):
set(my_output what_it_is.txt)
add_custom_command(
OUTPUT ${my_output}
COMMAND ${CMAKE_COMMAND} -E echo \"quoted string\" > ${my_output}
VERBATIM
)
And the output:
$ cat some_bin/what_it_is.txt
"quoted string"
In my limited experience, VERBATIM is usually the key if you're fighting escaping things in custom commands.
Note: I believe that the redirect is platform specific, so you might want to consider doing something like the file command in a CMake script and invoking that script in the custom command, COMMAND ${CMAKE_COMMAND} -P some_script.cmake.

cmake : How to copy prebuilt binary or script file instead of compiling anything local

I have shell scripts in some sub projects. These projects do not compile anything. What I want is to copy the scripts and / or pre-built binaries to the same location as it would if it compiled a local app.
#configure_file(test.sh test.sh COPYONLY)
add_custom_target(run ALL DEPENDS test.sh)
#add_custom_target(foo
# COMMAND cp test.sh
# ${CMAKE_CURRENT_BINARY_DIR}/test.sh)
add_custom_command(
OUTPUT test.sh
COMMAND cp test.sh ${CMAKE_CURRENT_BINARY_DIR}/test.sh
DEPENDS test.sh)
# COMMAND ${CMAKE_COMMAND} -E copy
# ${CMAKE_SOURCE_DIR}/test.sh
# ${CMAKE_CURRENT_BINARY_DIR}/test.sh)
This shows everything I tried.
configure_file works only if I do a clean build and never again. I need it to work every time I do a diff build.

cmake compare output of two executables [duplicate]

I have a console application called "foo", which takes a reference text file as input (in.txt) and generates text at standard output (I want to keep this behaviour).
In make (not cmake), I use a test target, which calls foo and redirects the output to a file (out.txt) as follows. Then, I use diff to compare the file out.txt with the expected refernece (ref.txt)
test:
./foo -a test/in.txt > test/out.txt
diff test/out.txt test/ref.txt
This works fine using make. Now my question is; how can I use cmake to create a similar Makefile?
From within a subdrectory called build, I tried
project(foo)
...
add_test(NAME test1 COMMAND ./foo ../test/in.txt > ../test/out.txt)
enable_testing()
Using cmake version 3.5, I get a Makefile without errors, but when I call make test, the test itself fails. It seems the cmake command add_test supports command line arguments, but not the redirection. I tried quotes and escaping witout success. Since I could not pass this part, I didn't try to use diff. I just imagine that I could pack foo and diff in one line using & as you can do with bash. That would be the second step.
Turning my comment into an answer
As #Tsyvarev has stated, CTest commands are not run in a shell's context. But you could just add the shell needed yourself and use e.g. sh as the command to be called with add_test().
I've run some tests with your example code and the following did work successfully:
add_test(NAME test1 COMMAND sh -c "$<TARGET_FILE:foo> ../test/in.txt > ../test/out.txt")
This solution is not platform independent (it depends on sh to be available in the search paths).
So if you want to be more flexible you could do something like:
include(FindUnixCommands)
file(TO_NATIVE_PATH "${CMAKE_CURRENT_SOURCE_DIR}/test/in.txt" _in)
file(TO_NATIVE_PATH "${CMAKE_CURRENT_SOURCE_DIR}/test/out.txt" _out)
if (BASH)
add_test(
NAME test1
COMMAND ${BASH} -c "$<TARGET_FILE:foo> ${_in} > ${_out}"
)
else()
if (WIN32)
add_test(
NAME test1
COMMAND ${CMAKE_COMMAND} -E chdir $<TARGET_FILE_DIR:foo> $ENV{ComSpec} /c "$<TARGET_FILE_NAME:foo> ${_in} > ${_out}"
)
else()
message(FATAL_ERROR "Unknown shell command for ${CMAKE_HOST_SYSTEM_NAME}")
endif()
endif()
Additionally there is the possibility to execute a more platform independent diff with ${CMAKE_COMMAND} -E compare_files <file1> <file2>. So you could simplify your complete makefile based example in CMake with:
add_custom_command(
TARGET foo
POST_BUILD
COMMAND ${CMAKE_COMMAND} -E echo "Running $<TARGET_FILE_NAME:foo> ..."
COMMAND foo in.txt > out.txt
WORKING_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR}/test
)
add_test(
NAME test1
COMMAND ${CMAKE_COMMAND} -E compare_files in.txt out.txt
WORKING_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR}/test
)
References
Integrate bash test scripts in cmake
CMake: piping commands to executable
cmake: make tests successfully passing part of the build process
They say you cannot:
There is no redirection of output using add_test arguments.
Unlike to commands in add_custom_command, which are executed as a part of makefile receipts (that is, in the context of some shell), tests are executed directly by CTest, without any shell involved. So, shell mechanisms don't work for tests.
You may create wrapper script, which calls program, given as parameter, and performs redirection, futher diff and so on. Then use this script (with appropriate arguments) as a COMMAND for add_test.

How to use redirection in cmake add_test

I have a console application called "foo", which takes a reference text file as input (in.txt) and generates text at standard output (I want to keep this behaviour).
In make (not cmake), I use a test target, which calls foo and redirects the output to a file (out.txt) as follows. Then, I use diff to compare the file out.txt with the expected refernece (ref.txt)
test:
./foo -a test/in.txt > test/out.txt
diff test/out.txt test/ref.txt
This works fine using make. Now my question is; how can I use cmake to create a similar Makefile?
From within a subdrectory called build, I tried
project(foo)
...
add_test(NAME test1 COMMAND ./foo ../test/in.txt > ../test/out.txt)
enable_testing()
Using cmake version 3.5, I get a Makefile without errors, but when I call make test, the test itself fails. It seems the cmake command add_test supports command line arguments, but not the redirection. I tried quotes and escaping witout success. Since I could not pass this part, I didn't try to use diff. I just imagine that I could pack foo and diff in one line using & as you can do with bash. That would be the second step.
Turning my comment into an answer
As #Tsyvarev has stated, CTest commands are not run in a shell's context. But you could just add the shell needed yourself and use e.g. sh as the command to be called with add_test().
I've run some tests with your example code and the following did work successfully:
add_test(NAME test1 COMMAND sh -c "$<TARGET_FILE:foo> ../test/in.txt > ../test/out.txt")
This solution is not platform independent (it depends on sh to be available in the search paths).
So if you want to be more flexible you could do something like:
include(FindUnixCommands)
file(TO_NATIVE_PATH "${CMAKE_CURRENT_SOURCE_DIR}/test/in.txt" _in)
file(TO_NATIVE_PATH "${CMAKE_CURRENT_SOURCE_DIR}/test/out.txt" _out)
if (BASH)
add_test(
NAME test1
COMMAND ${BASH} -c "$<TARGET_FILE:foo> ${_in} > ${_out}"
)
else()
if (WIN32)
add_test(
NAME test1
COMMAND ${CMAKE_COMMAND} -E chdir $<TARGET_FILE_DIR:foo> $ENV{ComSpec} /c "$<TARGET_FILE_NAME:foo> ${_in} > ${_out}"
)
else()
message(FATAL_ERROR "Unknown shell command for ${CMAKE_HOST_SYSTEM_NAME}")
endif()
endif()
Additionally there is the possibility to execute a more platform independent diff with ${CMAKE_COMMAND} -E compare_files <file1> <file2>. So you could simplify your complete makefile based example in CMake with:
add_custom_command(
TARGET foo
POST_BUILD
COMMAND ${CMAKE_COMMAND} -E echo "Running $<TARGET_FILE_NAME:foo> ..."
COMMAND foo in.txt > out.txt
WORKING_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR}/test
)
add_test(
NAME test1
COMMAND ${CMAKE_COMMAND} -E compare_files in.txt out.txt
WORKING_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR}/test
)
References
Integrate bash test scripts in cmake
CMake: piping commands to executable
cmake: make tests successfully passing part of the build process
They say you cannot:
There is no redirection of output using add_test arguments.
Unlike to commands in add_custom_command, which are executed as a part of makefile receipts (that is, in the context of some shell), tests are executed directly by CTest, without any shell involved. So, shell mechanisms don't work for tests.
You may create wrapper script, which calls program, given as parameter, and performs redirection, futher diff and so on. Then use this script (with appropriate arguments) as a COMMAND for add_test.