Re: [PATCH 6/8] sparse-index: complete partial expansion
- From
Victoria Dye <vdye@github.com>
- Date
- May 16, 2022, 20:38 UTC
- Message-ID
- <ac3869a5-3592-5408-587a-178afde3f7e9@github.com>
- In-Reply-To
- <eba63cc12af4f60320b34a54eef691b9f59d86bc.1652724693.git.gitgitgadget@gmail.com>
Derrick Stolee via GitGitGadget wrote:
Show 77 quoted lines
> From: Derrick Stolee <dstolee@microsoft.com>
>
> To complete the implementation of expand_to_pattern_list(), we need to
> detect when a sparse directory entry should remain sparse. This avoids a
> full expansion, so we now need to use the PARTIALLY_SPARSE mode to
> indicate this state.
>
> There still are no callers to this method, but we will add one in the
> next change.
>
> Signed-off-by: Derrick Stolee <derrickstolee@github.com>
> ---
> sparse-index.c | 41 +++++++++++++++++++++++++++++++++++++----
> 1 file changed, 37 insertions(+), 4 deletions(-)
>
> diff --git a/sparse-index.c b/sparse-index.c
> index 3d8eed585b5..0bad5503304 100644
> --- a/sparse-index.c
> +++ b/sparse-index.c
> @@ -297,8 +297,24 @@ void expand_to_pattern_list(struct index_state *istate,
> * continue. A NULL pattern set indicates a full expansion to a
> * full index.
> */
> - if (pl && !pl->use_cone_patterns)
> + if (pl && !pl->use_cone_patterns) {
> pl = NULL;
> + } else {
> + /*
> + * We might contract file entries into sparse-directory
> + * entries, and for that we will need the cache tree to
> + * be recomputed.
> + */
> + cache_tree_free(&istate->cache_tree);
> +
> + /*
> + * If there is a problem creating the cache tree, then we
> + * need to expand to a full index since we cannot satisfy
> + * the current request as a sparse index.
> + */
> + if (cache_tree_update(istate, WRITE_TREE_MISSING_OK))
> + pl = NULL;
> + }
>
> if (!istate->repo)
> istate->repo = the_repository;
> @@ -317,8 +333,14 @@ void expand_to_pattern_list(struct index_state *istate,
> full = xcalloc(1, sizeof(struct index_state));
> memcpy(full, istate, sizeof(struct index_state));
>
> + /*
> + * This slightly-misnamed 'full' index might still be sparse if we
> + * are only modifying the list of sparse directories. This hinges
> + * on whether we have a non-NULL pattern list.
> + */
> + full->sparse_index = pl ? PARTIALLY_SPARSE : COMPLETELY_FULL;
> +
> /* then change the necessary things */
> - full->sparse_index = 0;
> full->cache_alloc = (3 * istate->cache_alloc) / 2;
> full->cache_nr = 0;
> ALLOC_ARRAY(full->cache, full->cache_alloc);
> @@ -330,11 +352,22 @@ void expand_to_pattern_list(struct index_state *istate,
> struct cache_entry *ce = istate->cache[i];
> struct tree *tree;
> struct pathspec ps;
> + int dtype;
>
> if (!S_ISSPARSEDIR(ce->ce_mode)) {
> set_index_entry(full, full->cache_nr++, ce);
> continue;
> }
> +
> + /* We now have a sparse directory entry. Should we expand? */
> + if (pl &&
> + path_matches_pattern_list(ce->name, ce->ce_namelen,
> + NULL, &dtype,
> + pl, istate) <= 0) {If I'm reading this correctly, what this is doing is:
- if we have a sparse directory entry - ...and we're expanding only what matches the pattern list (i.e., not 'ensure_full_index') - ...and that sparse directory path is either *not matching* or *undecided whether it matches* the pattern list - ...then we add the sparse directory to the result index and continue.
The part that's confusing me is the "<= 0", which means a return value of 'UNDECIDED' from 'path_matches_pattern_list' adds the sparse directory as-is. At the moment, it looks like 'UNDECIDED' is only returned if not using cone patterns (so it shouldn't make a functional difference at this point), but wouldn't that return value indicate that the pattern *may or may not* match the path, so we should continue on to 'read_tree_at()'?
All that to say, should the condition be:
/* We now have a sparse directory entry. Should we expand? */
if (pl &&
path_matches_pattern_list(ce->name, ce->ce_namelen,
NULL, &dtype,
pl, istate) == NOT_MATCHED) {to reflect that a sparse directory should only be added to the index if we *know* it isn't matched?
To be clear, this is ultimately a non-functional nit - my question is mostly to make sure I understand the intent of the code.
Show 25 quoted lines
> + set_index_entry(full, full->cache_nr++, ce);
> + continue;
> + }
> +
> if (!(ce->ce_flags & CE_SKIP_WORKTREE))
> warning(_("index entry is a directory, but not sparse (%08x)"),
> ce->ce_flags);
> @@ -360,7 +393,7 @@ void expand_to_pattern_list(struct index_state *istate,
> /* Copy back into original index. */
> memcpy(&istate->name_hash, &full->name_hash, sizeof(full->name_hash));
> memcpy(&istate->dir_hash, &full->dir_hash, sizeof(full->dir_hash));
> - istate->sparse_index = 0;
> + istate->sparse_index = pl ? PARTIALLY_SPARSE : COMPLETELY_FULL;
> free(istate->cache);
> istate->cache = full->cache;
> istate->cache_nr = full->cache_nr;
> @@ -374,7 +407,7 @@ void expand_to_pattern_list(struct index_state *istate,
>
> /* Clear and recompute the cache-tree */
> cache_tree_free(&istate->cache_tree);
> - cache_tree_update(istate, 0);
> + cache_tree_update(istate, WRITE_TREE_MISSING_OK);
>
> trace2_region_leave("index",
> pl ? "expand_to_pattern_list" : "ensure_full_index",