From: Johannes Schindelin <Johannes.Schindelin@gmx.de>
To: Junio C Hamano <gitster@pobox.com>
Cc: Johannes Schindelin via GitGitGadget <gitgitgadget@gmail.com>,
git@vger.kernel.org
Subject: Re: [PATCH v2 2/2] git_path(): handle `.lock` files correctly
Date: Mon, 21 Oct 2019 22:26:26 +0200 (CEST) [thread overview]
Message-ID: <nycvar.QRO.7.76.6.1910212157350.46@tvgsbejvaqbjf.bet> (raw)
In-Reply-To: <xmqq1rva7sp7.fsf@gitster-ct.c.googlers.com>
Hi Junio,
On Fri, 18 Oct 2019, Junio C Hamano wrote:
> "Johannes Schindelin via GitGitGadget" <gitgitgadget@gmail.com>
> writes:
>
> > From: Johannes Schindelin <johannes.schindelin@gmx.de>
> >
> > Ever since worktrees were introduced, the `git_path()` function _really_
> > needed to be called e.g. to get at the path to `logs/HEAD` (`HEAD` is
> > specific to the worktree). However, the wrong path is returned for
> > `logs/HEAD.lock`.
> >
> > This does not matter as long as the Git executable is doing the asking,
> > as the path for that `index.lock` file is constructed from
> > `git_path("index")` by appending the `.lock` suffix.
>
> Is this still git_path("index") or is it now HEAD?
Darn. It is "logs/HEAD", of course.
> > Side note: Git GUI _does_ ask for `index.lock`, but that is already
> > resolved correctly.
>
> Is that s/but/and/?
It sounds better with an "and", you're right.
> > diff --git a/path.c b/path.c
> > index e3da1f3c4e..ff85692b45 100644
> > --- a/path.c
> > +++ b/path.c
> > @@ -268,7 +268,7 @@ static int trie_find(struct trie *root, const char *key, match_fn fn,
> > int result;
> > struct trie *child;
> >
> > - if (!*key) {
> > + if (!*key || !strcmp(key, ".lock")) {
>
> We only do strcmp for the tail part at the end of the path, so this
> should probably OK from performance point of view but semantically
> it is not very satisfying to see a special case for a single .suffix
> this deep in the callchain. I wonder if it is nicer to have the
> higher level callers notice ".lock" or whatever other suffixes they
> care about and ask the lower layer for a key with the suffix
> stripped?
Hmm. The parameter is provided as a `const char *`, so I cannot just
edit it. My first attempt at fixing this resulted in this commit:
-- snip --
path: switch `trie_find()` to a counted string
Before this patch, the `trie_find()` function would be fed a regular,
NUL-terminated string.
However, in the next commit, we want to strip any `.lock` suffix from
the argument, and the argument is provided as a `const char *` (i.e. we
do not want to modify it).
Let's use a string + length pair of parameters instead of a single
NUL-terminated string to open the door for this kind of manipulation.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
diff --git a/path.c b/path.c
index e3da1f3c4e2..b18d552c890 100644
--- a/path.c
+++ b/path.c
@@ -236,7 +236,8 @@ static void *add_to_trie(struct trie *root, const char *key, void *value)
return old;
}
-typedef int (*match_fn)(const char *unmatched, void *data, void *baton);
+typedef int (*match_fn)(const char *unmatched, size_t unmatched_len,
+ void *data, void *baton);
/*
* Search a trie for some key. Find the longest /-or-\0-terminated
@@ -261,22 +262,22 @@ typedef int (*match_fn)(const char *unmatched, void *data, void *baton);
* |-----------------|------------|---------------|--------------|
*
*/
-static int trie_find(struct trie *root, const char *key, match_fn fn,
- void *baton)
+static int trie_find(struct trie *root, const char *key, size_t key_len,
+ match_fn fn, void *baton)
{
int i;
int result;
struct trie *child;
- if (!*key) {
+ if (!key_len) {
/* we have reached the end of the key */
if (root->value && !root->len)
- return fn(key, root->value, baton);
+ return fn(key, key_len, root->value, baton);
else
return -1;
}
- for (i = 0; i < root->len; i++) {
+ for (i = 0; i < key_len && i < root->len; i++) {
/* Partial path normalization: skip consecutive slashes. */
if (key[i] == '/' && key[i+1] == '/') {
key++;
@@ -288,24 +289,26 @@ static int trie_find(struct trie *root, const char *key, match_fn fn,
/* Matched the entire compressed section */
key += i;
- if (!*key)
+ key_len -= i;
+
+ if (!key_len)
/* End of key */
- return fn(key, root->value, baton);
+ return fn(key, key_len, root->value, baton);
/* Partial path normalization: skip consecutive slashes */
- while (key[0] == '/' && key[1] == '/')
- key++;
+ while (key_len > 0 && key[0] == '/' && key[1] == '/')
+ key++, key_len--;
- child = root->children[(unsigned char)*key];
+ child = root->children[!key_len ? '0' : (unsigned char)*key];
if (child)
- result = trie_find(child, key + 1, fn, baton);
+ result = trie_find(child, key + 1, key_len - 1, fn, baton);
else
result = -1;
- if (result >= 0 || (*key != '/' && *key != 0))
+ if (result >= 0 || (key_len && *key != '/'))
return result;
if (root->value)
- return fn(key, root->value, baton);
+ return fn(key, key_len, root->value, baton);
else
return -1;
}
@@ -330,17 +333,18 @@ static void init_common_trie(void)
* Helper function for update_common_dir: returns 1 if the dir
* prefix is common.
*/
-static int check_common(const char *unmatched, void *value, void *baton)
+static int check_common(const char *unmatched, size_t unmatched_len,
+ void *value, void *baton)
{
struct common_dir *dir = value;
if (!dir)
return 0;
- if (dir->is_dir && (unmatched[0] == 0 || unmatched[0] == '/'))
+ if (dir->is_dir && (!unmatched_len || unmatched[0] == '/'))
return !dir->exclude;
- if (!dir->is_dir && unmatched[0] == 0)
+ if (!dir->is_dir && !unmatched_len)
return !dir->exclude;
return 0;
@@ -350,8 +354,10 @@ static void update_common_dir(struct strbuf *buf, int git_dir_len,
const char *common_dir)
{
char *base = buf->buf + git_dir_len;
+ size_t len = strlen(base);
+
init_common_trie();
- if (trie_find(&common_trie, base, check_common, NULL) > 0)
+ if (trie_find(&common_trie, base, len, check_common, NULL) > 0)
replace_dir(buf, git_dir_len, common_dir);
}
-- snap --
However, I think this is _really_ ugly and intrusive. The opposite of
what my goals were.
So I think I'll just bite the bullet and use a temporary copy if the
argument ends in `.lock`.
Ciao,
Dscho
next prev parent reply other threads:[~2019-10-21 20:26 UTC|newest]
Thread overview: 45+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-16 7:07 [PATCH 0/2] Handle git_path() with lock files correctly in worktrees Johannes Schindelin via GitGitGadget
2019-10-16 7:07 ` [PATCH 1/2] t1400: wrap setup code in test case Johannes Schindelin via GitGitGadget
2019-10-16 7:07 ` [PATCH 2/2] git_path(): handle `.lock` files correctly Johannes Schindelin via GitGitGadget
2019-10-16 11:04 ` SZEDER Gábor
2019-10-17 7:15 ` Junio C Hamano
2019-10-17 22:05 ` Johannes Schindelin
2019-10-18 11:06 ` SZEDER Gábor
2019-10-18 11:35 ` SZEDER Gábor
2019-10-21 16:00 ` [PATCH 0/5] path.c: a couple of common dir/trie fixes SZEDER Gábor
2019-10-21 16:00 ` [PATCH 1/5] Documentation: mention more worktree-specific exceptions SZEDER Gábor
2019-10-21 16:00 ` [PATCH 2/5] path.c: clarify trie_find()'s in-code comment SZEDER Gábor
2019-10-21 16:00 ` [PATCH 3/5] path.c: mark 'logs/HEAD' in 'common_list' as file SZEDER Gábor
2019-10-21 16:00 ` [PATCH 4/5] path.c: clarify two field names in 'struct common_dir' SZEDER Gábor
2019-10-21 16:00 ` [PATCH 5/5] path.c: don't call the match function without value in trie_find() SZEDER Gábor
2019-10-21 17:39 ` David Turner
2019-10-21 20:57 ` SZEDER Gábor
2019-10-23 4:01 ` Junio C Hamano
2019-10-23 16:20 ` SZEDER Gábor
2019-10-24 3:29 ` Junio C Hamano
2019-10-28 10:57 ` Johannes Schindelin
2019-10-28 12:00 ` SZEDER Gábor
2019-10-28 21:30 ` Johannes Schindelin
2019-10-18 11:42 ` [PATCH 0/2] path.c: minor common_list fixes SZEDER Gábor
2019-10-18 11:42 ` [PATCH 1/2] path.c: fix field name in 'struct common_dir' SZEDER Gábor
2019-10-18 11:42 ` [PATCH 2/2] path.c: mark 'logs/HEAD' in 'common_list' as file SZEDER Gábor
2019-10-21 19:35 ` [PATCH 0/2] path.c: minor common_list fixes Johannes Schindelin
2019-10-17 22:07 ` [PATCH v2 0/2] Handle git_path() with lock files correctly in worktrees Johannes Schindelin via GitGitGadget
2019-10-17 22:07 ` [PATCH v2 1/2] t1400: wrap setup code in test case Johannes Schindelin via GitGitGadget
2019-10-17 22:07 ` [PATCH v2 2/2] git_path(): handle `.lock` files correctly Johannes Schindelin via GitGitGadget
2019-10-18 1:23 ` Junio C Hamano
2019-10-18 12:35 ` SZEDER Gábor
2019-10-21 20:26 ` Johannes Schindelin [this message]
2019-10-23 2:12 ` Junio C Hamano
2019-10-21 21:54 ` [PATCH v3 0/2] Handle git_path() with lock files correctly in worktrees Johannes Schindelin via GitGitGadget
2019-10-21 21:54 ` [PATCH v3 1/2] t1400: wrap setup code in test case Johannes Schindelin via GitGitGadget
2019-10-21 21:54 ` [PATCH v3 2/2] git_path(): handle `.lock` files correctly Johannes Schindelin via GitGitGadget
2019-10-22 16:01 ` SZEDER Gábor
2019-10-23 3:38 ` Junio C Hamano
2019-10-28 12:01 ` Johannes Schindelin
2019-10-28 12:32 ` SZEDER Gábor
2019-10-28 17:30 ` Junio C Hamano
2019-10-28 12:57 ` [PATCH v4 0/2] Handle git_path() with lock files correctly in worktrees Johannes Schindelin via GitGitGadget
2019-10-28 12:57 ` [PATCH v4 1/2] t1400: wrap setup code in test case Johannes Schindelin via GitGitGadget
2019-10-28 12:57 ` [PATCH v4 2/2] git_path(): handle `.lock` files correctly Johannes Schindelin via GitGitGadget
2019-10-29 3:39 ` [PATCH v4 0/2] Handle git_path() with lock files correctly in worktrees Junio C Hamano
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