Subject: Re: [PATCH 1/2] relative_path should honor dos_drive_prefix

From: Torsten Bögershausen <[email-masked]>
Date: Thu, 12 Sep 2013 16:13:14 +0200

On 2013-09-12 11.12, Jiang Xin wrote:
> Tvangeste found that the "relative_path" function could not work
> properly on Windows if "in" and "prefix" have dos driver prefix.
> ($gmane/234434)
> 
> e.g., When execute: test-path-utils relative_path "C:/a/b" "D:/x/y",
> should return "C:/a/b", but returns "../../C:/a/b", which is wrong.
> 
> So make relative_path honor dos_drive_prefix, and add test cases
> for it in t0060.
> 
> Reported-by: Tvangeste <[email-masked]>
> Helped-by: Johannes Sixt <[email-masked]>
> Signed-off-by: Jiang Xin <[email-masked]>
> ---
>  path.c                | 20 ++++++++++++++++++++
>  t/t0060-path-utils.sh |  4 ++++
>  2 files changed, 24 insertions(+)
> 
> diff --git a/path.c b/path.c
> index 7f3324a..ffcdea1 100644
> --- a/path.c
> +++ b/path.c
> @@ -441,6 +441,16 @@ int adjust_shared_perm(const char *path)
>  	return 0;
>  }
>  
> +static int have_same_root(const char *path1, const char *path2)
> +{
> +	int is_abs1, is_abs2;
> +
> +	is_abs1 = is_absolute_path(path1);
> +	is_abs2 = is_absolute_path(path2);
> +	return (is_abs1 && is_abs2 && !strncasecmp(path1, path2, 1)) ||
                                       ^^^^^^^^^^^
I wonder: should strncasecmp() be replaced with strncmp_icase() ?

See dir.c: 
int strncmp_icase(const char *a, const char *b, size_t count)
{
	return ignore_case ? strncasecmp(a, b, count) : strncmp(a, b, count);
}
/Torsten

> +	       (!is_abs1 && !is_abs2);
> +}
> +
>  /*
>   * Give path as relative to prefix.
>   *
> @@ -461,6 +471,16 @@ const char *relative_path(const char *in, const char *prefix,
>  	else if (!prefix_len)
>  		return in;
>  
> +	if (have_same_root(in, prefix)) {
> +		/* bypass dos_drive, for "c:" is identical to "C:" */
> +		if (has_dos_drive_prefix(in)) {
> +			i = 2;
> +			j = 2;
> +		}
> +	} else {
> +		return in;
> +	}
> +
>  	while (i < prefix_len && j < in_len && prefix[i] == in[j]) {
>  		if (is_dir_sep(prefix[i])) {
>  			while (is_dir_sep(prefix[i]))
> diff --git a/t/t0060-path-utils.sh b/t/t0060-path-utils.sh
> index 76c7792..c3c3b33 100755
> --- a/t/t0060-path-utils.sh
> +++ b/t/t0060-path-utils.sh
> @@ -208,6 +208,10 @@ relative_path a/b/	a/b		./
>  relative_path a		a/b		../
>  relative_path x/y	a/b		../../x/y
>  relative_path a/c	a/b		../c
> +relative_path a/b	/x/y		a/b
> +relative_path /a/b	x/y		/a/b	POSIX
> +relative_path d:/a/b	D:/a/c		../b	MINGW
> +relative_path C:/a/b	D:/a/c		C:/a/b	MINGW
>  relative_path a/b	"<empty>"	a/b
>  relative_path a/b 	"<null>"	a/b
>  relative_path "<empty>"	/a/b		./
>