Re: [PATCH] commit.c: Replace starts_with() with skip_prefix()
On Mon, Mar 3, 2014 at 10:23 AM, karthik nayak wrote:
> Hello Eric,
> Thanks for Pointing out everything, i had a thorough look and fixed a
> couple of things.
> Here is an Updated Patch.
> - Removed unnecessary code and variables.
> - Replaced all instances of starts_with() with skip_prefix()
This commentary is important for the on-going email discussion but
does not belong in the commit message for the permanent project
history, so place it below the "---" line just under your sign-off.
Explaining what changed since the last attempt, as you do here, is a
good thing. To further ease the review process, supply a link to the
previous attempt, like this [1].
[1]: http://thread.gmane.org/gmane.comp.version-control.git/243194
> Replace starts_with() with skip_prefix() for better reading purposes.
> Also to replace "buf + strlen(author )" by skip_prefix(), which is
> saved in a new "const char" variable "buf_skipprefix".
The second sentence is really the meat of this change, and not at all
incidental as "Also" implies. You should use it (or a refinement of
it) as your commit message. The first sentence doesn't particularly
add much and can easily be dropped.
> Signed-off-by: Karthik Nayak
> ---
> commit.c | 13 -
> 1 file changed, 8 insertions(+), 5 deletions(-)
>
> diff --git a/commit.c b/commit.c
> index 6bf4fe0..e5dc2e2 100644
> --- a/commit.c
> +++ b/commit.c
> @@ -552,6 +552,7 @@ static void record_author_date(struct
> author_date_slab *author_date,
> char *buffer = NULL;
> struct ident_split ident;
> char *date_end;
> + const char *buf_skipprefix;
Read this response by Junio [2] to another GSoC candidate which
explains why this is a poor variable name and how to craft a better
one.
[2]: http://thread.gmane.org/gmane.comp.version-control.git/243231/focus=243259
> unsigned long date;
>
> if (!commit->buffer) {
> @@ -562,18 +563,20 @@ static void record_author_date(struct
> author_date_slab *author_date,
> return;
> }
>
> + buf_skipprefix = skip_prefix(buf, "author ");
Unfortunately, your patch is badly whitespace-damaged as if it was
pasted into the mailer and mangled. (Your first submission did not
have this problem.) If you can, use "git send-email" to avoid such
corruption.
> +
> for (buf = commit->buffer ? commit->buffer : buffer;
> buf;
> buf = line_end + 1) {
> line_end = strchrnul(buf, '\n');
> - if (!starts_with(buf, "author ")) {
> + if (!buf_skipprefix) {
> 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 "))) ||
> + buf_skipprefix,
> + line_end - buf_skipprefix) ||
Looks reasonable (sans whitespace damage).
> !ident.date_begin || !ident.date_end)
> goto fail_exit; /* malformed "author" line */
> break;
> @@ -1113,7 +1116,7 @@ int parse_signed_commit(const unsigned char *sha1,
> next = next ? next + 1 : tail;
> if (in_signature && line[0] == ' ')
> sig = line + 1;
> - else if (starts_with(line, gpg_sig_header) &&
> + else if (skip_prefix(line, gpg_sig_header) &&
> line[gpg_sig_header_len] == ' ')
> sig = line + gpg_sig_header_len + 1;
> if (sig) {
> @@ -1193,7 +1196,7 @@ 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)) {
> + if (skip_prefix(buf, sigcheck_gpg_status[i].check + 1)) {
> /* At the very beginning of the buffer */
> found = buf + strlen(sigcheck_gpg_status[i].check + 1);
> } else {
For these two sets of changes, unless you are actually taking
advantage of the return value of skip_prefix(), the mere mechanical
replacement of starts_with() with skip_prefix() actually hurts
readability. Examine each of these cases more carefully to determine
whether skip_prefix() is in fact useful. If so, take advantage of it.
If not, explain in the patch commentary why skip_prefix() doesn't
help.
> --
> 1.9.0.138.g2de3478
--
To unsubscribe from this list: send the line "unsubscribe git" in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [PATCH] commit.c: Replace starts_with() with skip_prefix()
Hello Eric,
Thanks for Pointing out everything, i had a thorough look and fixed a
couple of things.
Here is an Updated Patch.
- Removed unnecessary code and variables.
- Replaced all instances of starts_with() with skip_prefix()
Replace starts_with() with skip_prefix() for better reading purposes.
Also to replace "buf + strlen(author )" by skip_prefix(), which is
saved in a new "const char" variable "buf_skipprefix".
Signed-off-by: Karthik Nayak
---
commit.c | 13 -
1 file changed, 8 insertions(+), 5 deletions(-)
diff --git a/commit.c b/commit.c
index 6bf4fe0..e5dc2e2 100644
--- a/commit.c
+++ b/commit.c
@@ -552,6 +552,7 @@ static void record_author_date(struct
author_date_slab *author_date,
char *buffer = NULL;
struct ident_split ident;
char *date_end;
+ const char *buf_skipprefix;
unsigned long date;
if (!commit->buffer) {
@@ -562,18 +563,20 @@ static void record_author_date(struct
author_date_slab *author_date,
return;
}
+ buf_skipprefix = skip_prefix(buf, "author ");
+
for (buf = commit->buffer ? commit->buffer : buffer;
buf;
buf = line_end + 1) {
line_end = strchrnul(buf, '\n');
- if (!starts_with(buf, "author ")) {
+ if (!buf_skipprefix) {
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 "))) ||
+ buf_skipprefix,
+ line_end - buf_skipprefix) ||
!ident.date_begin || !ident.date_end)
goto fail_exit; /* malformed "author" line */
break;
@@ -1113,7 +1116,7 @@ int parse_signed_commit(const unsigned char *sha1,
next = next ? next + 1 : tail;
if (in_signature && line[0] == ' ')
sig = line + 1;
- else if (starts_with(line, gpg_sig_header) &&
+ else if (skip_prefix(line, gpg_sig_header) &&
line[gpg_sig_header_len] == ' ')
sig = line + gpg_sig_header_len + 1;
if (sig) {
@@ -1193,7 +1196,7 @@ 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)) {
+ if (skip_prefix(buf, sigcheck_gpg_status[i].check + 1)) {
/* At the very beginning of the buffer */
found = buf + strlen(sigcheck_gpg_status[i].check + 1);
} else {
--
1.9.0.138.g2de3478
--
To unsubscribe from this list: send the line "unsubscribe git" in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [PATCH] commit.c: Replace starts_with() with skip_prefix()
Thanks for the submission. Some commentary below to expose you to the
review process on this project...
On Mon, Mar 3, 2014 at 2:47 AM, Karthik Nayak wrote:
> Replace with skip_prefix(), which uses the inbuilt function
> strcmp() to compare.
Explaining the purpose of the change is indeed important, however,
this description misses the mark. See below.
> Other Places were this can be implemented:
> commit.c : line 1117
> commit.c : line 1197
Bonus points if you actually follow through with this.
> Signed-off-by: Karthik Nayak
> ---
> commit.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/commit.c b/commit.c
> index 6bf4fe0..1e181cf 100644
> --- a/commit.c
> +++ b/commit.c
> @@ -552,6 +552,7 @@ static void record_author_date(struct author_date_slab
> *author_date,
> char *buffer = NULL;
> struct ident_split ident;
> char *date_end;
> + char *flag_sp; /* stores return value of skip_prefix() */
It's not clear why this variable is needed. It's only assigned (below)
but never referenced. Also, the name conveys little or no meaning. If
you need a comment to explain the purpose of the variable, that's
probably a good indication that it's poorly named.
> unsigned long date;
>
> if (!commit->buffer) {
> @@ -566,7 +567,7 @@ 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 ")) {
> + if ((flag_sp = skip_prefix(buf, "author ")) == NULL) {
Unfortunately, this change makes the code more difficult to read.
Let's review the GSoC microproject:
Rewrite commit.c:record_author_date() to use skip_prefix().
Are there other places in this file where skip_prefix() would
be **more readable** than starts_with()?
Note the part I **highlighted**. This is a good clue that use of
skip_prefix() can be used to simplify the code. Examine
record_author_date() more carefully and see if you can identify how to
do so.
> if (!line_end[0] || line_end[1] == '\n')
> return; /* end of header */
> continue;
> --
> 1.9.0.138.g2de3478
--
To unsubscribe from this list: send the line "unsubscribe git" in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
