Re: [PATCH v3 2/2] fsck.c: Rewrite fsck_commit() to use skip_prefix()

2014-03-13 Thread Junio C Hamano
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()

2014-03-13 Thread Junio C Hamano
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()

2014-03-12 Thread Yuxuan Shui
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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