Re: [Qemu-devel] [PATCH v5 00/12] Convert over to use keycodemapdb

[Daniel P. Berrange]

On Tue, Sep 19, 2017 at 04:26:22PM +0200, Gerd Hoffmann wrote:
>   Hi,
> 
> > > The Makefile checks the output of this script, and if it indicates
> > > that an submodule update is required, it uses an ifeq() to add a
> > > dependancy between "Makefile" and a phony target that re-runs
> > > configure (which in turns updates the submodules). If no update was
> > > required, then no dependancy from Makefile gets added, so build
> > > runs
> > > normally.
> 
> Neat trick.  I think re-running configure should not be needed though. 
> Touching the Makefile should be enough to make make re-evaluating
> things after updating submodules ...

Yeah, re-running configure would only be needed if one of the submodules
had code that needed to be run by configure (eg before we removed pixman
we could re-run pixman/configure).

Since we killed pixman though, we might as well stick with doing it
all in the Makefile and ignore configure.

> diff --git a/Makefile b/Makefile
> index b53fc69a60..a9a0cea6d9 100644
> --- a/Makefile
> +++ b/Makefile
> @@ -31,6 +31,27 @@ CONFIG_ALL=y
>  -include config-all-devices.mak
>  -include config-all-disas.mak
>  
> +ifeq (0,$(MAKELEVEL))
> +  git_module_status := $(shell \
> +    cd '$(SRC_PATH)'; \
> +    test -d .git || { echo 0; exit; }; \
> +    ./scripts/git-submodule.sh status; \
> +    echo $$?; \
> +  )
> +
> +ifeq (1,$(git_module_status))
> +Makefile: git-submodule-update
> +
> +.PHONY: git-submodule-update
> +
> +git-submodule-update:
> +     @echo "GIT submodules out of date, updating."
> +     (cd $(SRC_PATH); ./scripts/git-submodule.sh update)
> +     @touch Makefile
> +endif
> +endif
> +
> +
>  config-host.mak: $(SRC_PATH)/configure $(SRC_PATH)/pc-bios
>       @echo $@ is out-of-date, running configure
>       @# TODO: The next lines include code which supports a smooth
> diff --git a/.gitignore b/.gitignore
> index cf65316863..0c5fda2fdb 100644
> --- a/.gitignore
> +++ b/.gitignore
> @@ -111,6 +111,7 @@
>  /docs/version.texi
>  *.tps
>  .stgit-*
> +.git-submodule-status
>  cscope.*
>  tags
>  TAGS
> diff --git a/scripts/git-submodule.sh b/scripts/git-submodule.sh
> new file mode 100755
> index 0000000000..07d36c2b82
> --- /dev/null
> +++ b/scripts/git-submodule.sh
> @@ -0,0 +1,22 @@
> +#!/bin/bash
> +
> +# config
> +modules="dtc"
> +substat=".git-submodule-status"
> +
> +# drop modules not checked out
> +modules="$(git submodule status $modules | awk '/^[^-]/ { print $2
> }')"
> +
> +case "$1" in
> +status)
> +     test -f "$substat" || exit 1
> +     git submodule status $modules > "${substat}.tmp"
> +     trap "rm -f ${substat}.tmp" EXIT
> +     diff "${substat}" "${substat}.tmp" >/dev/null
> +     exit $?
> +     ;;
> +update)
> +     git submodule update $modules
> +     git submodule status $modules > "${substat}"
> +     ;;
> +esac

Yep, this looks reasonable. I'll incorporate this in my keycodemapdb
patch series & repost later this week.

Regards,
Daniel
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