[PATCH v5] commit.c: use skip_prefix() instead of starts_with()

[PATCH v5] commit.c: use skip_prefix() instead of starts_with()

[Tanay Abhra]

In record_author_date() & parse_gpg_output(), the callers of
starts_with() not just want to know if the string starts with the
prefix, but also can benefit from knowing the string that follows
the prefix.

By using skip_prefix(), we can do both at the same time.

Helped-by: Max Horn <max@quendi.de>
Helped-by: Junio C Hamano <gitster@pobox.com>
Helped-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Tanay Abhra <tanayabh@gmail.com>
---
Patch V5 Minor revision of indentation
Patch V4  Identation improved, removed useless comment. [1]
		Thanks to Junio C Hamano and Max Horn.
[1] http://article.gmane.org/gmane.comp.version-control.git/243388

Patch V3 Variable naming improved, removed assignments inside conditionals.
        Thanks to Junio C Hamano and Max Horn.

Patch V2 Corrected email formatting ,reapplied the implementation according to suggestions.
        Thanks to Michael Haggerty.

This is in respect to GSoC microproject #10.

In record_author_date(), extra and useless calls to strlen due to using starts_with()
were removed by using skip_prefix(). Extra variable "ident_line" was used as "buf" is used in
for loop update check.

Other usages of starts_with() in the same file can be found with,

$ grep -n starts_with commit.c

1116:           else if (starts_with(line, gpg_sig_header) &&
1196:           if (starts_with(buf, sigcheck_gpg_status[i].check + 1)) {

The starts_with() in line 1116 was left as it is, as strlen values were pre computed as
global variables, and replacing may hamper the clarity.
The starts_with() in line 1196 was replaced as it abstracts way the skip_prefix part by
directly using the function.
Also skip_prefix() is inline when compared to starts_with().

---
 commit.c | 14 ++++++--------
 1 file changed, 6 insertions(+), 8 deletions(-)

diff --git a/commit.c b/commit.c
index 6bf4fe0..d37675c 100644
--- a/commit.c
+++ b/commit.c
@@ -548,7 +548,7 @@ define_commit_slab(author_date_slab, unsigned long);
 static void record_author_date(struct author_date_slab *author_date,
 			       struct commit *commit)
 {
-	const char *buf, *line_end;
+	const char *buf, *line_end, *ident_line;
 	char *buffer = NULL;
 	struct ident_split ident;
 	char *date_end;
@@ -566,14 +566,14 @@ static void record_author_date(struct author_date_slab *author_date,
 	     buf;
 	     buf = line_end + 1) {
 		line_end = strchrnul(buf, '\n');
-		if (!starts_with(buf, "author ")) {
+		ident_line = skip_prefix(buf, "author ");
+		if (!ident_line) {
 			if (!line_end[0] || line_end[1] == '\n')
 				return; /* end of header */
 			continue;
 		}
 		if (split_ident_line(&ident,
-				     buf + strlen("author "),
-				     line_end - (buf + strlen("author "))) ||
+				     ident_line, line_end - ident_line) ||
 		    !ident.date_begin || !ident.date_end)
 			goto fail_exit; /* malformed "author" line */
 		break;
@@ -1193,10 +1193,8 @@ static void parse_gpg_output(struct signature_check *sigc)
 	for (i = 0; i < ARRAY_SIZE(sigcheck_gpg_status); i++) {
 		const char *found, *next;
 
-		if (starts_with(buf, sigcheck_gpg_status[i].check + 1)) {
-			/* At the very beginning of the buffer */
-			found = buf + strlen(sigcheck_gpg_status[i].check + 1);
-		} else {
+		found = skip_prefix(buf, sigcheck_gpg_status[i].check + 1);
+		if(!found) {
 			found = strstr(buf, sigcheck_gpg_status[i].check);
 			if (!found)
 				continue;
-- 
1.9.0

Re: [PATCH v5] commit.c: use skip_prefix() instead of starts_with()

[Michael Haggerty]

On 03/04/2014 11:07 PM, Tanay Abhra wrote:
> In record_author_date() & parse_gpg_output(), the callers of
> starts_with() not just want to know if the string starts with the
> prefix, but also can benefit from knowing the string that follows
> the prefix.
> 
> By using skip_prefix(), we can do both at the same time.
> 
> Helped-by: Max Horn <max@quendi.de>
> Helped-by: Junio C Hamano <gitster@pobox.com>
> Helped-by: Michael Haggerty <mhagger@alum.mit.edu>
> Signed-off-by: Tanay Abhra <tanayabh@gmail.com>
> ---
> Patch V5 Minor revision of indentation
> Patch V4  Identation improved, removed useless comment. [1]
> 		Thanks to Junio C Hamano and Max Horn.
> [1] http://article.gmane.org/gmane.comp.version-control.git/243388
> 
> Patch V3 Variable naming improved, removed assignments inside conditionals.
>         Thanks to Junio C Hamano and Max Horn.
> 
> Patch V2 Corrected email formatting ,reapplied the implementation according to suggestions.
>         Thanks to Michael Haggerty.
> 
> This is in respect to GSoC microproject #10.
> 
> In record_author_date(), extra and useless calls to strlen due to using starts_with()
> were removed by using skip_prefix(). Extra variable "ident_line" was used as "buf" is used in
> for loop update check.
> 
> Other usages of starts_with() in the same file can be found with,
> 
> $ grep -n starts_with commit.c
> 
> 1116:           else if (starts_with(line, gpg_sig_header) &&
> 1196:           if (starts_with(buf, sigcheck_gpg_status[i].check + 1)) {
> 
> The starts_with() in line 1116 was left as it is, as strlen values were pre computed as
> global variables, and replacing may hamper the clarity.
> The starts_with() in line 1196 was replaced as it abstracts way the skip_prefix part by
> directly using the function.
> Also skip_prefix() is inline when compared to starts_with().
> 
> ---
>  commit.c | 14 ++++++--------
>  1 file changed, 6 insertions(+), 8 deletions(-)
> 
> diff --git a/commit.c b/commit.c
> index 6bf4fe0..d37675c 100644
> --- a/commit.c
> +++ b/commit.c
> @@ -548,7 +548,7 @@ define_commit_slab(author_date_slab, unsigned long);
>  static void record_author_date(struct author_date_slab *author_date,
>  			       struct commit *commit)
>  {
> -	const char *buf, *line_end;
> +	const char *buf, *line_end, *ident_line;
>  	char *buffer = NULL;
>  	struct ident_split ident;
>  	char *date_end;
> @@ -566,14 +566,14 @@ static void record_author_date(struct author_date_slab *author_date,
>  	     buf;
>  	     buf = line_end + 1) {
>  		line_end = strchrnul(buf, '\n');
> -		if (!starts_with(buf, "author ")) {
> +		ident_line = skip_prefix(buf, "author ");
> +		if (!ident_line) {
>  			if (!line_end[0] || line_end[1] == '\n')
>  				return; /* end of header */
>  			continue;
>  		}
>  		if (split_ident_line(&ident,
> -				     buf + strlen("author "),
> -				     line_end - (buf + strlen("author "))) ||
> +				     ident_line, line_end - ident_line) ||
>  		    !ident.date_begin || !ident.date_end)
>  			goto fail_exit; /* malformed "author" line */
>  		break;
> @@ -1193,10 +1193,8 @@ static void parse_gpg_output(struct signature_check *sigc)
>  	for (i = 0; i < ARRAY_SIZE(sigcheck_gpg_status); i++) {
>  		const char *found, *next;
>  
> -		if (starts_with(buf, sigcheck_gpg_status[i].check + 1)) {
> -			/* At the very beginning of the buffer */
> -			found = buf + strlen(sigcheck_gpg_status[i].check + 1);
> -		} else {
> +		found = skip_prefix(buf, sigcheck_gpg_status[i].check + 1);
> +		if(!found) {

Nit: There should be a space between "if" and the opening parenthesis.

>  			found = strstr(buf, sigcheck_gpg_status[i].check);
>  			if (!found)
>  				continue;
> 

Michael

-- 
Michael Haggerty
mhagger@alum.mit.edu
http://softwareswirl.blogspot.com/

Re: [PATCH v5] commit.c: use skip_prefix() instead of starts_with()

[Michael Haggerty]

On 03/21/2014 04:48 PM, Michael Haggerty wrote:
> On 03/04/2014 11:07 PM, Tanay Abhra wrote:
>> [...]
>> +		found = skip_prefix(buf, sigcheck_gpg_status[i].check + 1);
>> +		if(!found) {
> 
> Nit: There should be a space between "if" and the opening parenthesis.

Oops, I see I am too late.  Junio must have fixed this when queuing the
patch.

Michael

-- 
Michael Haggerty
mhagger@alum.mit.edu
http://softwareswirl.blogspot.com/