Re: [PATCH] git gc --auto: defer on battery

> This patch modifies git gc --auto so that it will not always repack when
> a user is on battery.
> 
> It introduces the new gc.deferonbattery configuration variable, which
> defaults to true. If it's true and the user is on battery, it will not
> run git gc --auto.
> 
> Signed-off-by: Miklos Vajna <vmiklos@frugalware.org>
> ---
> 
> On Mon, Mar 31, 2008 at 01:26:12AM +0200, Björn Steinbrink <B.Steinbrink@gmx.de> wrote:
> > Hm, maybe move that check into need_to_gc instead? Seems a bit weird
> > to
> > lie about the status instead of just skipping the status check.
> 
> Right, I've moved the check to need_to_gc().
> 
> > The /proc stuff is already deprecated IIRC, the new file to check on
> > Linux is /sys/class/power_supply/AC/online.
> 
> And that makes the patch smaller as well. :)

> Something like this?
> 
>  Documentation/git-gc.txt |    4 ++++
>  builtin-gc.c             |   24 ++++++++++++++++++++++++
>  2 files changed, 28 insertions(+), 0 deletions(-)
> 
> diff --git a/Documentation/git-gc.txt b/Documentation/git-gc.txt
> index d424a4e..7d54148 100644
> --- a/Documentation/git-gc.txt
> +++ b/Documentation/git-gc.txt
> @@ -104,6 +104,10 @@ The optional configuration variable 'gc.pruneExpire' controls how old
>  the unreferenced loose objects have to be before they are pruned.  The
>  default is "2 weeks ago".
>  
> +The optional configuration variable 'gc.deferonbattery' determines if
> +`git gc --auto` should be disabled if the system is running on battery.
> +This defaults to true.
> +
>  See Also
>  --------
>  linkgit:git-prune[1]
> diff --git a/builtin-gc.c b/builtin-gc.c
> index 8cef36f..512a357 100644
> --- a/builtin-gc.c
> +++ b/builtin-gc.c
> @@ -23,6 +23,7 @@ static const char * const builtin_gc_usage[] = {
>  };
>  
>  static int pack_refs = 1;
> +static int defer_on_battery = 1;
>  static int aggressive_window = -1;
>  static int gc_auto_threshold = 6700;
>  static int gc_auto_pack_limit = 50;
> @@ -67,6 +68,10 @@ static int gc_config(const char *var, const char *value)
>  		prune_expire = xstrdup(value);
>  		return 0;
>  	}
> +	if (!strcmp(var, "gc.deferonbattery")) {
> +		defer_on_battery = git_config_bool(var, value);
> +		return 0;
> +	}
>  	return git_default_config(var, value);
>  }
>  
> @@ -157,6 +162,20 @@ static int too_many_packs(void)
>  	return gc_auto_pack_limit <= cnt;
>  }
>  
> +static int is_on_battery(void)
> +{
> +	FILE *fp;
> +	unsigned int state = 1;
> +
> +	if ((fp = fopen("/sys/class/power_supply/AC/online", "r"))) {
> +		if (fscanf(fp, "%d", &state) != 1)
> +			state = 1;
> +		fclose(fp);
> +		return state != 1;
> +	}
> +	return 0;
> +}
> +
>  static int need_to_gc(void)
>  {
>  	/*
> @@ -176,6 +195,11 @@ static int need_to_gc(void)
>  		append_option(argv_repack, "-A", MAX_ADD);
>  	else if (!too_many_loose_objects())
>  		return 0;
> +
> +	if(defer_on_battery && is_on_battery()) {
> +		fprintf(stderr, "Auto packing deferred; on battery");
> +		return 0;
> +	}
>  	return 1;
>  }
>