[CMake] trouble with quotation marks (cmake 2.6 for WinCE)

[Michael Hertling]

On 08/13/2010 09:49 PM, Ris Misner wrote:
> Hi,
> 
> I am new to using cmake, and trying to get a custom build command to embed quotes for a project that I'm compiling in MS visual studio on a windows machine.
> 
> I have this in my cmake file:
> 
> COMMAND ${FLEX_EXECUTABLE} -t ${WEBCORE_DIR}/css/tokenizer.flex | "${PERL_EXECUTABLE}" ${MAKE_TOKENIZER} > ${DERIVED_SOURCES_DIR}/tokenizer.cpp
> 
> I need to achieve this custom build step in my generated vcproj file:
> 
> C:\cygwin\bin\flex.exe -t E:\Wolverine\git-Jason\git-WebKit\WebCore\css\tokenizer.flex | "C:\cygwin\bin\perl.exe" E:\Wolverine\git-Jason\git-WebKit\WebCore\css\maketokenizer > E:\Wolverine\git-Jason\git-WebKit\WebKitBuild\DerivedSources\tokenizer.cpp
> 
> Please note the wrapping quotes around "C:\cygwin\bin\perl.exe".  That's critical, or the DOS shell complains that 'C:' is not a valid command.
> 
> Cmake is removing the quotes and giving me this:
> 
> C:\cygwin\bin\flex.exe -t E:\Wolverine\git-Jason\git-WebKit\WebCore\css\tokenizer.flex | C:\cygwin\bin\perl.exe E:\Wolverine\git-Jason\git-WebKit\WebCore\css\maketokenizer > E:\Wolverine\git-Jason\git-WebKit\WebKitBuild\DerivedSources\tokenizer.cpp
> 
> Which fails like I said.  DOS complains that 'C:' is not a valid command, and doesn't parse it correctly without the quotes around the path to perl.exe.
> 
> When I try to escape the quotes, like this:
> 
> COMMAND ${FLEX_EXECUTABLE} -t ${WEBCORE_DIR}/css/tokenizer.flex | \"${PERL_EXECUTABLE}\" ${MAKE_TOKENIZER} > ${DERIVED_SOURCES_DIR}/tokenizer.cpp
> 
> Cmake preserves the backslashes, and generates this:
> 
> C:\cygwin\bin\flex.exe -t E:\Wolverine\git-Jason\git-WebKit\WebCore\css\tokenizer.flex | \"C:\cygwin\bin\perl.exe\" E:\Wolverine\git-Jason\git-WebKit\WebCore\css\maketokenizer > E:\Wolverine\git-Jason\git-WebKit\WebKitBuild\DerivedSources\tokenizer.cpp
> 
> 
> I have also tried to work around it by performing a double macro expansion like this:
> 
> SET(cmd "${FLEX_EXECUTABLE} -t ${WEBCORE_DIR}/css/tokenizer.flex | \"${PERL_EXECUTABLE}\" ${MAKE_TOKENIZER} > ${DERIVED_SOURCES_DIR}/tokenizer.cpp")
> COMMAND ${cmd}
> 
> It doesn't help... I get this:
> 
> "C:\cygwin\bin\flex.exe -t E:\Wolverine\git-Jason\git-WebKit\WebCore\css\tokenizer.flex | \"C:\cygwin\bin\perl.exe\" E:\Wolverine\git-Jason\git-WebKit\WebCore\css\maketokenizer > E:\Wolverine\git-Jason\git-WebKit\WebKitBuild\DerivedSources\tokenizer.cpp"
> 
> The backslashes to escape the quotes were preserved (breaking it) and the wrapping quotes around the outside of the whole command string were also preserved, which makes the DOS shell think this is one long file name.
> 
> Whatever I try, the quotes are either completely removed, or the backslashes to escape them are preserved as \" instead of becoming a simple "
> 
> I also tried putting the quotes in their own escaped substrings like this: "\""${PERL_EXECUTABLE}"\""
> 
> COMMAND ${FLEX_EXECUTABLE} -t ${WEBCORE_DIR}/css/tokenizer.flex | "\""${PERL_EXECUTABLE}"\"" ${MAKE_TOKENIZER} > ${DERIVED_SOURCES_DIR}/tokenizer.cpp
> 
> And I was surprised to see this output:
> 
> 
> C:\cygwin\bin\flex.exe -t E:/Wolverine/git-Jason/git-WebKit/WebCore/css/tokenizer.flex | \" C:/cygwin/bin/perl.exe\"\"\" E:/Wolverine/git-Jason/git-WebKit/WebCore/css/maketokenizer > E:/Wolverine/git-Jason/git-WebKit/WebKitBuild/DerivedSources/tokenizer.cpp
> 
> 
> So then I tried to put just the " into its own expansion like this:
> 
> SET(QUOTE \")
> COMMAND ${FLEX_EXECUTABLE} -t ${WEBCORE_DIR}/css/tokenizer.flex | ${QUOTE}${PERL_EXECUTABLE}${QUOTE} ${MAKE_TOKENIZER} > ${DERIVED_SOURCES_DIR}/tokenizer.cpp
> 
> But the backslash to escape the quote is still preserved that way too, and I get this:
> 
> 
> C:\cygwin\bin\flex.exe -t E:/Wolverine/git-Jason/git-WebKit/WebCore/css/tokenizer.flex | \"C:/cygwin/bin/perl.exe\" E:/Wolverine/git-Jason/git-WebKit/WebCore/css/maketokenizer > E:/Wolverine/git-Jason/git-WebKit/WebKitBuild/DerivedSources/tokenizer.cpp
> 
> 
> 
> Is there any way to make this generate the output that I need?  Is this a bug in the version of cmake that I'm using (2.6 for windows ce) or is there a trick to the cmake syntax?
> 
> 
> For reference details, the complete context of my custom command comes from this macro:
> 
> SET(MAKE_TOKENIZER ${WEBCORE_DIR}/css/maketokenizer)
> # - Create ${DERIVED_SOURCES_DIR}/tokenizer.cpp
> # GENERATE_TOKENIZER()
> MACRO(GENERATE_TOKENIZER)
>   # do a little dance to embed quotes around perl.exe, or cmake messes them up
>   ADD_CUSTOM_COMMAND(
>     OUTPUT ${DERIVED_SOURCES_DIR}/tokenizer.cpp
>     DEPENDS ${WEBCORE_DIR}/css/tokenizer.flex ${MAKE_TOKENIZER}
>     COMMAND ${FLEX_EXECUTABLE} -t ${WEBCORE_DIR}/css/tokenizer.flex | "${PERL_EXECUTABLE}" ${MAKE_TOKENIZER} > ${DERIVED_SOURCES_DIR}/tokenizer.cpp
>     VERBATIM)
> ENDMACRO()
> GENERATE_TOKENIZER() # this is called out in a separate file
> 
> I am using cmake 2.6 for Windows CE because that's the version that was branched to support builds for Windows CE (so unfortunately if this is a bug that has been fixed, I can't update to cmake 2.8 - was there a work-around in cmake 2.6?)

FYI: On *nix with CMake 2.8.2, I also didn't manage to force a quoted
command, say "perl", into the Makefiles instead of the usually unquoted
one unless the command contains blanks. Apparently, ADD_CUSTOM_COMMAND()
has its own ideas for handling quotes.

If your problem still persists, the following workaround could possibly
help: Create a file tokenizer.cmake, e.g. by FILE(WRITE ...) or from a
template via CONFIGURE_FILE() or hardcoded in the source directory:

FILE(WRITE ${CMAKE_BINARY_DIR}/tokenizer.cmake "EXECUTE_PROCESS(
COMMAND ${FLEX_EXECUTABLE} -t ${WEBCORE_DIR}/css/tokenizer.flex
COMMAND \"${PERL_EXECUTABLE}\" ${MAKE_TOKENIZER}
OUTPUT_FILE ${DERIVED_SOURCES_DIR}/tokenizer.cpp\n")

Note the escaped quotes around ${PERL_EXECUTABLE}.

Now, change the custom command to:

ADD_CUSTOM_COMMAND(
    OUTPUT ${DERIVED_SOURCES_DIR}/tokenizer.cpp
    DEPENDS ${WEBCORE_DIR}/css/tokenizer.flex ${MAKE_TOKENIZER}
    COMMAND ${CMAKE_COMMAND} -P ${CMAKE_BINARY_DIR}/tokenizer.cmake
    VERBATIM)

Perhaps, EXECUTE_PROCESS()'s COMMAND option treats the quotes or
whatever is your issue's reason better than ADD_CUSTOM_COMMAND()'s
w.r.t. to your shell, but I can't test - currently, no access to any
windowed machine... ;-)

Hope that helps.

Regards,

Michael