Re: [PATCH v2 3/7] reftable/refname: refactor binary search over refnames

From: Justin Tobler <jltobler@gmail.com>
Date: Apr 2, 2024, 16:27 UTC
Message-ID: <zvw6ezlchqyl5tq4zuia7az5b3i4swwvtm42muwe4i7gngswgz@ztujhb4ruewm>
In-Reply-To: <9ffcf45c32f22245c9978436affcefa914fc6927.1711361340.git.ps@pks.im>

On 24/03/25 11:10AM, Patrick Steinhardt wrote:

Show 32 quoted lines

> It is comparatively hard to understand how exactly the binary search
> over refnames works given that the function and variable names are not
> exactly easy to grasp. Rename them to make this more obvious. This
> should not result in any change in behaviour.
> 
> Signed-off-by: Patrick Steinhardt <ps@pks.im>
> ---
>  reftable/refname.c | 44 ++++++++++++++++++++++----------------------
>  1 file changed, 22 insertions(+), 22 deletions(-)
> 
> diff --git a/reftable/refname.c b/reftable/refname.c
> index 64eba1b886..9ec488d727 100644
> --- a/reftable/refname.c
> +++ b/reftable/refname.c
> @@ -12,15 +12,15 @@
>  #include "refname.h"
>  #include "reftable-iterator.h"
>  
> -struct find_arg {
> -	char **names;
> -	const char *want;
> +struct refname_needle_lesseq_args {
> +	char **haystack;
> +	const char *needle;
>  };
>  
> -static int find_name(size_t k, void *arg)
> +static int refname_needle_lesseq(size_t k, void *arg)
>  {
> -	struct find_arg *f_arg = arg;
> -	return strcmp(f_arg->names[k], f_arg->want) >= 0;
> +	struct refname_needle_lesseq_args *f_arg = arg;

nit: Looks like the `f_arg` variable name is a remnant from when the type was called `find_arg`. Do we want to rename this to `args`? We could also rename `void *arg` to `void *_args`.

Show 26 quoted lines

> +	return strcmp(f_arg->needle, f_arg->haystack[k]) <= 0;
>  }
>  
>  static int modification_has_ref(struct modification *mod, const char *name)
> @@ -29,21 +29,21 @@ static int modification_has_ref(struct modification *mod, const char *name)
>  	int err = 0;
>  
>  	if (mod->add_len > 0) {
> -		struct find_arg arg = {
> -			.names = mod->add,
> -			.want = name,
> +		struct refname_needle_lesseq_args arg = {
> +			.haystack = mod->add,
> +			.needle = name,
>  		};
> -		size_t idx = binsearch(mod->add_len, find_name, &arg);
> +		size_t idx = binsearch(mod->add_len, refname_needle_lesseq, &arg);
>  		if (idx < mod->add_len && !strcmp(mod->add[idx], name))
>  			return 0;
>  	}
>  
>  	if (mod->del_len > 0) {
> -		struct find_arg arg = {
> -			.names = mod->del,
> -			.want = name,
> +		struct refname_needle_lesseq_args arg = {

nit: In the other commits we use `args`. Do we want to be consistent?

-Justin

Show 43 quoted lines

> +			.haystack = mod->del,
> +			.needle = name,
>  		};
> -		size_t idx = binsearch(mod->del_len, find_name, &arg);
> +		size_t idx = binsearch(mod->del_len, refname_needle_lesseq, &arg);
>  		if (idx < mod->del_len && !strcmp(mod->del[idx], name))
>  			return 1;
>  	}
> @@ -71,11 +71,11 @@ static int modification_has_ref_with_prefix(struct modification *mod,
>  	int err = 0;
>  
>  	if (mod->add_len > 0) {
> -		struct find_arg arg = {
> -			.names = mod->add,
> -			.want = prefix,
> +		struct refname_needle_lesseq_args arg = {
> +			.haystack = mod->add,
> +			.needle = prefix,
>  		};
> -		size_t idx = binsearch(mod->add_len, find_name, &arg);
> +		size_t idx = binsearch(mod->add_len, refname_needle_lesseq, &arg);
>  		if (idx < mod->add_len &&
>  		    !strncmp(prefix, mod->add[idx], strlen(prefix)))
>  			goto done;
> @@ -90,11 +90,11 @@ static int modification_has_ref_with_prefix(struct modification *mod,
>  			goto done;
>  
>  		if (mod->del_len > 0) {
> -			struct find_arg arg = {
> -				.names = mod->del,
> -				.want = ref.refname,
> +			struct refname_needle_lesseq_args arg = {
> +				.haystack = mod->del,
> +				.needle = ref.refname,
>  			};
> -			size_t idx = binsearch(mod->del_len, find_name, &arg);
> +			size_t idx = binsearch(mod->del_len, refname_needle_lesseq, &arg);
>  			if (idx < mod->del_len &&
>  			    !strcmp(ref.refname, mod->del[idx]))
>  				continue;
> -- 
> 2.44.GIT
>