On 2/5/2023 4:12 PM, Ævar Arnfjörð Bjarmason wrote:
>
> On Sat, Feb 04 2023, René Scharfe wrote:
>
>> Use size_t to store the original length of the strbuf tree_len, as
>> that's the correct type.
>>
>> Don't double the allocated size of the strbuf when adding a subdirectory
>> name. Only extend it to fit that name and a slash.
>>
>> Signed-off-by: René Scharfe <l.s.r@xxxxxx>
>> ---
>> cache-tree.c | 4 ++--
>> 1 file changed, 2 insertions(+), 2 deletions(-)
>>
>> diff --git a/cache-tree.c b/cache-tree.c
>> index 9af457f47c..35f7617164 100644
>> --- a/cache-tree.c
>> +++ b/cache-tree.c
>> @@ -760,7 +760,7 @@ static void prime_cache_tree_rec(struct repository *r,
>> struct tree_desc desc;
>> struct name_entry entry;
>> int cnt;
>> - int base_path_len = tree_path->len;
>> + size_t base_path_len = tree_path->len;
>>
>> oidcpy(&it->oid, &tree->object.oid);
>>
>> @@ -785,7 +785,7 @@ static void prime_cache_tree_rec(struct repository *r,
>> */
>> if (r->index->sparse_index) {
>> strbuf_setlen(tree_path, base_path_len);
>> - strbuf_grow(tree_path, base_path_len + entry.pathlen + 1);
>> + strbuf_grow(tree_path, entry.pathlen + 1);
>> strbuf_add(tree_path, entry.path, entry.pathlen);
>> strbuf_addch(tree_path, '/');
>> }
>
> The size_t conversion is trivially correct.
I agree, and thanks for finding and fixing this issue.
Upon reading strbuf_grow(), I would expect it to work the same
as ALLOC_GROW(), but its documentation clearly states a very
different result.
> One wonders if (even for this index-related code) we really need such
> careful management of growth, and could instead do with:
>
> strbuf_setlen(tree_path, base_path_len);
> strbuf_add(tree_path, entry.path, entry.pathlen);
> strbuf_addch(tree_path, '/');
This would be my preferred way to go here.
> Or even just:
>
> strbuf_addf(tree_path, "%*.s/", (int)entry.pathlen, entry.path);
Please do not add "addf" functions that can be run in tight loops.
It's faster to do strbuf_add() followed by strbuf_addch().
Thanks,
-Stolee
