Re: [PATCH v3 2/2] fsck.c: Rewrite fsck_commit() to use skip_prefix()
Junio C Hamano writes:
>> -if (memcmp(buffer, "tree ", 5))
>> +buffer = skip_prefix(buffer, "tree ");
>> +if (buffer == NULL)
>
> We encourage people to write this as:
>
> if (!buffer)
>
> The same comment applies to other new lines in this patch.
I also see a lot of repetitions in the code, before or after the
patch. I wonder if a further refactoring along this line on top of
these two patches might be worth considering.
No, I am not proud of sneaking tree_sha1[] array pointers as a
seemingly boolean-looking must-match-header parameter into the
helper, but this is merely a "how about going in this direction"
weather-balloon patch, so
fsck.c | 83 --
1 file changed, 61 insertions(+), 22 deletions(-)
diff --git a/fsck.c b/fsck.c
index 6aab23b..a3eea7f 100644
--- a/fsck.c
+++ b/fsck.c
@@ -279,10 +279,55 @@ static int fsck_ident(const char **ident, struct object
*obj, fsck_error error_f
return 0;
}
+static int fsck_object_line(struct commit *commit, fsck_error error_func,
+ const char **buffer, const char *header,
+ unsigned char must_match_header[])
+{
+ unsigned char sha1_buf[20];
+ unsigned char *sha1 = must_match_header ? must_match_header : sha1_buf;
+ const char *buf;
+
+ buf = skip_prefix(*buffer, header);
+ if (!buf) {
+ if (must_match_header)
+ return error_func(&commit->object, FSCK_ERROR,
+ "invalid format - expected '%.*s'
line",
+ (int) strlen(header) - 1,
+ header);
+ return 1;
+ }
+ if (get_sha1_hex(buf, sha1) || buf[40] != '\n')
+ return error_func(&commit->object, FSCK_ERROR,
+ "invalid '%.*s' line format - bad sha1",
+ (int) strlen(header) - 1,
+ header);
+ *buffer = buf + 41;
+ return 0;
+}
+
+static int fsck_ident_line(struct commit *commit, fsck_error error_func,
+ const char **buffer, const char *header)
+{
+ const char *buf;
+ int err;
+
+ buf = skip_prefix(*buffer, header);
+ if (!buf)
+ return error_func(&commit->object, FSCK_ERROR,
+ "invalid format - expected '%.*s' line",
+ (int) strlen(header) - 1,
+ header);
+ err = fsck_ident(&buf, &commit->object, error_func);
+ if (err)
+ return err;
+ *buffer = buf;
+ return 0;
+}
+
static int fsck_commit(struct commit *commit, fsck_error error_func)
{
- const char *buffer = commit->buffer, *tmp;
- unsigned char tree_sha1[20], sha1[20];
+ const char *buffer = commit->buffer;
+ unsigned char tree_sha1[20];
struct commit_graft *graft;
int parents = 0;
int err;
@@ -290,18 +335,17 @@ static int fsck_commit(struct commit *commit, fsck_error
error_func)
if (commit->date == ULONG_MAX)
return error_func(&commit->object, FSCK_ERROR, "invalid
author/committer line");
- buffer = skip_prefix(buffer, "tree ");
- if (!buffer)
- return error_func(&commit->object, FSCK_ERROR, "invalid format
- expected 'tree' line");
- if (get_sha1_hex(buffer, tree_sha1) || buffer[40] != '\n')
- return error_func(&commit->object, FSCK_ERROR, "invalid 'tree'
line format - bad sha1");
- buffer += 41;
- while ((tmp = skip_prefix(buffer, "parent "))) {
- buffer = tmp;
- if (get_sha1_hex(buffer, sha1) || buffer[40] != '\n')
- return error_func(&commit->object, FSCK_ERROR, "invalid
'parent' line format - bad sha1");
- buffer += 41;
- parents++;
+ err = fsck_object_line(commit, error_func, &buffer, "tree ", tree_sha1);
+ if (err)
+ return err;
+ while (1) {
+ err = fsck_object_line(commit, error_func, &buffer, "parent ",
NULL);
+ if (err < 0)
+ return err;
+ else if (!err)
+ parents++;
+ else
+ break;
}
graft = lookup_commit_graft(commit->object.sha1);
if (graft) {
@@ -324,16 +368,11 @@ static int fsck_commit(struct commit *commit, fsck_error
error_func)
if (p || parents)
return error_func(&commit->object, FSCK_ERROR, "parent
objects missing");
}
- buffer = skip_prefix(buffer, "author ");
- if (!buffer)
- return error_func(&commit->object, FSCK_ERROR, "invalid format
- expected 'author' line");
- err = fsck_ident(&buffer, &commit->obje
Re: [PATCH v3 2/2] fsck.c: Rewrite fsck_commit() to use skip_prefix()
Yuxuan Shui writes:
> Currently we use memcmp() in fsck_commit() to check if buffer start
> with a certain prefix, and skip the prefix if it does. This is exactly
> what skip_prefix() does. And since skip_prefix() has a self-explaintory
> name, this could make the code more readable.
>
> Signed-off-by: Yuxuan Shui
> ---
> fsck.c | 24 +---
> 1 file changed, 13 insertions(+), 11 deletions(-)
>
> diff --git a/fsck.c b/fsck.c
> index 7776660..7e6b829 100644
> --- a/fsck.c
> +++ b/fsck.c
> @@ -281,7 +281,7 @@ static int fsck_ident(const char **ident, struct object
> *obj, fsck_error error_f
>
> static int fsck_commit(struct commit *commit, fsck_error error_func)
> {
> - const char *buffer = commit->buffer;
> + const char *buffer = commit->buffer, *tmp;
> unsigned char tree_sha1[20], sha1[20];
> struct commit_graft *graft;
> int parents = 0;
> @@ -290,15 +290,17 @@ static int fsck_commit(struct commit *commit,
> fsck_error error_func)
> if (commit->date == ULONG_MAX)
> return error_func(&commit->object, FSCK_ERROR, "invalid
> author/committer line");
>
> - if (memcmp(buffer, "tree ", 5))
> + buffer = skip_prefix(buffer, "tree ");
> + if (buffer == NULL)
We encourage people to write this as:
if (!buffer)
The same comment applies to other new lines in this patch.
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[PATCH v3 2/2] fsck.c: Rewrite fsck_commit() to use skip_prefix()
Currently we use memcmp() in fsck_commit() to check if buffer start
with a certain prefix, and skip the prefix if it does. This is exactly
what skip_prefix() does. And since skip_prefix() has a self-explaintory
name, this could make the code more readable.
Signed-off-by: Yuxuan Shui
---
fsck.c | 24 +---
1 file changed, 13 insertions(+), 11 deletions(-)
diff --git a/fsck.c b/fsck.c
index 7776660..7e6b829 100644
--- a/fsck.c
+++ b/fsck.c
@@ -281,7 +281,7 @@ static int fsck_ident(const char **ident, struct object
*obj, fsck_error error_f
static int fsck_commit(struct commit *commit, fsck_error error_func)
{
- const char *buffer = commit->buffer;
+ const char *buffer = commit->buffer, *tmp;
unsigned char tree_sha1[20], sha1[20];
struct commit_graft *graft;
int parents = 0;
@@ -290,15 +290,17 @@ static int fsck_commit(struct commit *commit, fsck_error
error_func)
if (commit->date == ULONG_MAX)
return error_func(&commit->object, FSCK_ERROR, "invalid
author/committer line");
- if (memcmp(buffer, "tree ", 5))
+ buffer = skip_prefix(buffer, "tree ");
+ if (buffer == NULL)
return error_func(&commit->object, FSCK_ERROR, "invalid format
- expected 'tree' line");
- if (get_sha1_hex(buffer+5, tree_sha1) || buffer[45] != '\n')
+ if (get_sha1_hex(buffer, tree_sha1) || buffer[40] != '\n')
return error_func(&commit->object, FSCK_ERROR, "invalid 'tree'
line format - bad sha1");
- buffer += 46;
- while (!memcmp(buffer, "parent ", 7)) {
- if (get_sha1_hex(buffer+7, sha1) || buffer[47] != '\n')
+ buffer += 41;
+ while ((tmp = skip_prefix(buffer, "parent "))) {
+ buffer = tmp;
+ if (get_sha1_hex(buffer, sha1) || buffer[40] != '\n')
return error_func(&commit->object, FSCK_ERROR, "invalid
'parent' line format - bad sha1");
- buffer += 48;
+ buffer += 41;
parents++;
}
graft = lookup_commit_graft(commit->object.sha1);
@@ -322,15 +324,15 @@ static int fsck_commit(struct commit *commit, fsck_error
error_func)
if (p || parents)
return error_func(&commit->object, FSCK_ERROR, "parent
objects missing");
}
- if (memcmp(buffer, "author ", 7))
+ buffer = skip_prefix(buffer, "author ");
+ if (buffer == NULL)
return error_func(&commit->object, FSCK_ERROR, "invalid format
- expected 'author' line");
- buffer += 7;
err = fsck_ident(&buffer, &commit->object, error_func);
if (err)
return err;
- if (memcmp(buffer, "committer ", strlen("committer ")))
+ buffer = skip_prefix(buffer, "committer ");
+ if (buffer == NULL)
return error_func(&commit->object, FSCK_ERROR, "invalid format
- expected 'committer' line");
- buffer += strlen("committer ");
err = fsck_ident(&buffer, &commit->object, error_func);
if (err)
return err;
--
1.9.0
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