[pacman-dev] [PATCH] pacsort: only look at versions in file mode

[Andrew Gregory]

On 11/04/13 at 12:02pm, Dave Reisner wrote:
> alpm_pkg_vercmp rightfully considers foo-1-1 to be newer than foo-1:1-1
> because of the leading characters. So, in file mode, pacsort must
> necessarily ignore the package name when performing comparisons. Create
> a struct, for convenience, which overlays pointers and lengths to the
> name and version within a filename. Using this, we can avoid some
> amount of heap allocation, and do better at comparing versions for
> similar package names.
> 
> Fixes FS#37631.
> 
> Signed-off-by: Dave Reisner <dreisner at archlinux.org>
> ---
>  src/util/pacsort.c       | 69 +++++++++++++++++++++++++++++++++++++++++-------
>  test/util/pacsorttest.sh | 11 +++++++-
>  2 files changed, 69 insertions(+), 11 deletions(-)
> 
> diff --git a/src/util/pacsort.c b/src/util/pacsort.c
> index 687e558..cbee316 100644
> --- a/src/util/pacsort.c
> +++ b/src/util/pacsort.c
> @@ -28,6 +28,15 @@
>  
>  #define DELIM ' '
>  
> +#ifndef MIN
> +#define MIN(a, b)      \
> +	__extension__({           \
> +		__typeof__(a) _a = (a); \
> +		__typeof__(b) _b = (b); \
> +		_a < _b ? _a : _b;           \
> +	})
> +#endif
> +
>  struct buffer_t {
>  	char *mem;
>  	size_t len;
> @@ -40,6 +49,14 @@ struct list_t {
>  	size_t maxcount;
>  };
>  
> +struct pkgmeta_t {
> +	const char *pkgname;
> +	size_t pkgname_len;
> +
> +	const char *pkgver;
> +	size_t pkgver_len;
> +};
> +
>  static struct options_t {
>  	int order;
>  	int sortkey;
> @@ -258,6 +275,30 @@ static const char *nth_column(const char *string)
>  	return prev;
>  }
>  
> +static void extract_pkgmeta(const char *path, struct pkgmeta_t *meta) {
> +	const char *pkgver_end;
> +
> +	memset(meta, 0, sizeof(struct pkgmeta_t));
> +
> +	meta->pkgname = basename(path);

I don't think we should use basename here.  You're currently using the
GNU version, which seems to be little more than strrchr(path, '/')
anyway and is likely to confuse people expecting the POSIX version,
which can modify its argument or return a pointer to statically
allocated memory.

> +	pkgver_end = strrchr(meta->pkgname, '-');
> +
> +	/* read backwards through pkgrel */
> +	for(meta->pkgver = pkgver_end - 1;
> +			meta->pkgver > meta->pkgname && *meta->pkgver != '-';
> +			--meta->pkgver)
> +		;
> +	/* read backwards through pkgver */
> +	for(--meta->pkgver;
> +			meta->pkgver > meta->pkgname && *meta->pkgver != '-';
> +			--meta->pkgver)
> +		;
> +	++meta->pkgver;
> +
> +	meta->pkgname_len = meta->pkgver - meta->pkgname - 1;
> +	meta->pkgver_len = pkgver_end - meta->pkgver;
> +}
> +

Could we just expose _alpm_splitname (or a simplified version of it
without the hash) and remove this?

>  static int vercmp(const void *p1, const void *p2)
>  {
>  	const char *name1, *name2;
> @@ -280,17 +321,25 @@ static int vercmp(const void *p1, const void *p2)
>  	if(opts.filemode) {
>  		if(fnmatch("*-*.pkg.tar.?z", name1, 0) == 0 &&
>  			 fnmatch("*-*.pkg.tar.?z", name2, 0) == 0) {
> -			const char *start, *end;
> -
> -			start = strrchr(name1, '/');
> -			start = start ? start + 1 : name1;
> -			end = strrchr(name1, '-');
> -			fn1 = strndup(start, end - start);
> +			struct pkgmeta_t pkgmeta1, pkgmeta2;
> +			int namecmp;
> +
> +			/* Extract name and version */
> +			extract_pkgmeta(name1, &pkgmeta1);
> +			extract_pkgmeta(name2, &pkgmeta2);
> +
> +			/* If the package names aren't the same, there's no sense in comparing
> +			 * the versions. Short circuit and return a comparison based on the
> +			 * pkgnames. This probably could be cleaner, but I'm favoring clarity
> +			 * over cleverness. */
> +			namecmp = memcmp(pkgmeta1.pkgname, pkgmeta2.pkgname,
> +					MIN(pkgmeta1.pkgname_len, pkgmeta2.pkgname_len));
> +			if(pkgmeta1.pkgname_len != pkgmeta2.pkgname_len || namecmp != 0) {
> +				return opts.order * namecmp;
> +			}
>  
> -			start = strrchr(name2, '/');
> -			start = start ? start + 1 : name2;
> -			end = strrchr(name2, '-');
> -			fn2 = strndup(start, end - start);
> +			fn1 = strndup(pkgmeta1.pkgver, pkgmeta1.pkgver_len);
> +			fn2 = strndup(pkgmeta2.pkgver, pkgmeta2.pkgver_len);
>  
>  			name1 = fn1;
>  			name2 = fn2;

If we're going to convert input to a struct like this, why not just
store the original input in the struct as well and convert everything
up front?   vercmp can use the stored info for --files and the
original input otherwise.

> diff --git a/test/util/pacsorttest.sh b/test/util/pacsorttest.sh
> index ac16c45..8382603 100755
> --- a/test/util/pacsorttest.sh
> +++ b/test/util/pacsorttest.sh
> @@ -21,7 +21,7 @@
>  # default binary if one was not specified as $1
>  bin=${1:-${PMTEST_UTIL_DIR}pacsort}
>  # holds counts of tests
> -total=23
> +total=26
>  run=0
>  failure=0
>  
> @@ -89,6 +89,15 @@ runtest $in $in "filename sort with uneven leading path components" "--files"
>  in="firefox-18.0-2-i686.pkg.tar.xz\nfirefox-18.0.1-1-x86_64.pkg.tar.gz\n"
>  runtest $in $in "filename sort with different extensions" "--files"
>  
> +in="/packages/dialog-1.2_20131001-1-x86_64.pkg.tar.xz\n/packages/dialog-1:1.2_20130928-1-x86_64.pkg.tar.xz\n"
> +runtest $in $in "filename sort with epoch" "--files"
> +
> +in="/packages/dia-log-1:1.2_20130928-1-x86_64.pkg.tar.xz\n/packages/dialog-1.2_20131001-1-x86_64.pkg.tar.xz\n"
> +runtest $in $in "filename sort with epoch" "--files"
> +
> +in="/packages/dialoggg-1:1.2_20130928-1-x86_64.pkg.tar.xz\n/packages/dialog-1.2_20131001-1-x86_64.pkg.tar.xz\n"
> +runtest $in $in "filename sort with epoch" "--files"
> +
>  # generate some long input/expected for the next few tests
>  declare normal reverse names_normal names_reverse
>  for ((i=1; i<600; i++)); do
> -- 
> 1.8.4.2