Re: [GSoC][PATCH 3/3] clone: use dir-iterator to avoid explicit dir traversal
- From
Thomas Gummerer <t.gummerer@gmail.com>
- Date
- Feb 23, 2019, 21:48 UTC
- Message-ID
- <20190223214856.GQ6085@hank.intra.tgummerer.com>
- In-Reply-To
- <20190223190309.6728-4-matheus.bernardino@usp.br>
On 02/23, Matheus Tavares wrote:
Show 27 quoted lines
> Replace usage of opendir/readdir/closedir API to traverse directories > recursively, at copy_or_link_directory function, by the dir-iterator > API. This simplifies the code and avoid recursive calls to > copy_or_link_directory. > > This process also brings some safe behaviour changes to > copy_or_link_directory: > - It will no longer follows symbolic links. This is not a problem, > since the function is only used to copy .git/objects directory, and > symbolic links are not expected there. > - Hidden directories won't be skipped anymore. In fact, it is odd that > the function currently skip hidden directories but not hidden files. > The reason for that could be unintentional: probably the intention > was to skip '.' and '..' only, but it ended up accidentally skipping > all directories starting with '.'. Again, it must not be a problem > not to skip hidden dirs since hidden dirs/files are not expected at > .git/objects. > - Now, copy_or_link_directory will call die() in case of an error on > openddir, readdir or lstat, inside dir_iterator_advance. That means > it will abort in case of an error trying to fetch any iteration > entry. > > Signed-off-by: Matheus Tavares <matheus.bernardino@usp.br> > --- > Changes in v2: > - Improved patch message > - Removed a now unused variable
s/variable/parameter/ I believe?
> - Put warning on stat error back > - Added pedantic option to dir-iterator initialization > - Modified copy_or_link_directory not to skip hidden paths
Thanks, these descriptions are very useful for reviewers that had a look at previous rounds.
Show 59 quoted lines
> builtin/clone.c | 47 ++++++++++++++++++++++++++++-------------------
> 1 file changed, 28 insertions(+), 19 deletions(-)
>
> diff --git a/builtin/clone.c b/builtin/clone.c
> index 862d2ea69c..515dc91d63 100644
> --- a/builtin/clone.c
> +++ b/builtin/clone.c
> @@ -23,6 +23,8 @@
> #include "transport.h"
> #include "strbuf.h"
> #include "dir.h"
> +#include "dir-iterator.h"
> +#include "iterator.h"
> #include "sigchain.h"
> #include "branch.h"
> #include "remote.h"
> @@ -411,42 +413,45 @@ static void mkdir_if_missing(const char *pathname, mode_t mode)
> }
>
> static void copy_or_link_directory(struct strbuf *src, struct strbuf *dest,
> - const char *src_repo, int src_baselen)
> + const char *src_repo)
> {
> - struct dirent *de;
> - struct stat buf;
> int src_len, dest_len;
> - DIR *dir;
> -
> - dir = opendir(src->buf);
> - if (!dir)
> - die_errno(_("failed to open '%s'"), src->buf);
> + struct dir_iterator *iter;
> + int iter_status;
> + struct stat st;
>
> mkdir_if_missing(dest->buf, 0777);
>
> + iter = dir_iterator_begin(src->buf, 1);
> +
> strbuf_addch(src, '/');
> src_len = src->len;
> strbuf_addch(dest, '/');
> dest_len = dest->len;
>
> - while ((de = readdir(dir)) != NULL) {
> + while ((iter_status = dir_iterator_advance(iter)) == ITER_OK) {
> strbuf_setlen(src, src_len);
> - strbuf_addstr(src, de->d_name);
> + strbuf_addstr(src, iter->relative_path);
> strbuf_setlen(dest, dest_len);
> - strbuf_addstr(dest, de->d_name);
> - if (stat(src->buf, &buf)) {
> + strbuf_addstr(dest, iter->relative_path);
> +
> + /*
> + * dir_iterator_advance already calls lstat to populate iter->st
> + * but, unlike stat, lstat does not checks for permissions on
> + * the given path.
> + */Hmm, lstat does check the permissions on the path, it just doesn't follow symlinks. I think I actually mislead you in my previous review here, and was reading the code in dir-iterator.c all wrong.
I thought it said "if (errno == ENOENT) warning(...)", however the condition is "errno != ENOENT", which is why I thought we were loosing warnings when errno == EACCES for example.
As we decided that we would no longer follow symlinks now, I think we can actually get rid of the stat call here. Sorry about the confusion.
Show 45 quoted lines
> + if (stat(src->buf, &st)) {
> warning (_("failed to stat %s\n"), src->buf);
> continue;
> }
> - if (S_ISDIR(buf.st_mode)) {
> - if (de->d_name[0] != '.')
> - copy_or_link_directory(src, dest,
> - src_repo, src_baselen);
> +
> + if (S_ISDIR(iter->st.st_mode)) {
> + mkdir_if_missing(dest->buf, 0777);
> continue;
> }
>
> /* Files that cannot be copied bit-for-bit... */
> - if (!strcmp(src->buf + src_baselen, "/info/alternates")) {
> + if (!strcmp(iter->relative_path, "info/alternates")) {
> copy_alternates(src, dest, src_repo);
> continue;
> }
> @@ -463,7 +468,11 @@ static void copy_or_link_directory(struct strbuf *src, struct strbuf *dest,
> if (copy_file_with_time(dest->buf, src->buf, 0666))
> die_errno(_("failed to copy file to '%s'"), dest->buf);
> }
> - closedir(dir);
> +
> + if (iter_status != ITER_DONE) {
> + strbuf_setlen(src, src_len);
> + die(_("failed to iterate over '%s'"), src->buf);
> + }
> }
>
> static void clone_local(const char *src_repo, const char *dest_repo)
> @@ -481,7 +490,7 @@ static void clone_local(const char *src_repo, const char *dest_repo)
> get_common_dir(&dest, dest_repo);
> strbuf_addstr(&src, "/objects");
> strbuf_addstr(&dest, "/objects");
> - copy_or_link_directory(&src, &dest, src_repo, src.len);
> + copy_or_link_directory(&src, &dest, src_repo);
> strbuf_release(&src);
> strbuf_release(&dest);
> }
> --
> 2.20.1
>