From: Derrick Stolee <dsto...@microsoft.com>
The parent and recursive patterns allowed by the "cone mode"
option in sparse-checkout are restrictive enough that we
can avoid using the regex parsing. Everything is based on
prefix matches, so we can use hashsets to store the prefixes
from the sparse-checkout file. When checking a path, we can
strip path entries from the path and check the hashset for
an exact match.
As a test, I created a cone-mode sparse-checkout file for the
Linux repository that actually includes every file. This was
constructed by taking every folder in the Linux repo and creating
the pattern pairs here:
/$folder/*
!/$folder/*/*
This resulted in a sparse-checkout file sith 8,296 patterns.
Running 'git read-tree -mu HEAD' on this file had the following
performance:
core.sparseCheckout=false: 0.21 s (0.00 s)
core.sparseCheckout=true: 3.75 s (3.50 s)
core.sparseCheckout=cone: 0.23 s (0.01 s)
The times in parentheses above correspond to the time spent
in the first clear_ce_flags() call, according to the trace2
performance traces.
While this example is contrived, it demonstrates how these
patterns can slow the sparse-checkout feature.
Signed-off-by: Derrick Stolee <dsto...@microsoft.com>
---
Documentation/git-sparse-checkout.txt | 1 -
dir.c | 154 +++++++++++++++++++++++++-
dir.h | 27 +++++
t/t1091-sparse-checkout-builtin.sh | 8 ++
4 files changed, 183 insertions(+), 7 deletions(-)
diff --git a/Documentation/git-sparse-checkout.txt
b/Documentation/git-sparse-checkout.txt
index 463319055b..7ade827370 100644
--- a/Documentation/git-sparse-checkout.txt
+++ b/Documentation/git-sparse-checkout.txt
@@ -85,7 +85,6 @@ negate patterns. For example, to remove the file `unwanted`:
!unwanted
----------------
-
## CONE PATTERN SET
The full pattern set allows for arbitrary pattern matches and complicated
diff --git a/dir.c b/dir.c
index d021c908e5..2c5ff89a72 100644
--- a/dir.c
+++ b/dir.c
@@ -599,6 +599,99 @@ void parse_exclude_pattern(const char **pattern,
*patternlen = len;
}
+static int el_hashmap_cmp(const void *unused_cmp_data,
+ const void *a, const void *b, const void *key)
+{
+ const struct exclude_entry *ee1 = a;
+ const struct exclude_entry *ee2 = b;
+
+ return strncmp(ee1->pattern, ee2->pattern, ee1->patternlen);
+}
+
+static void add_exclude_to_hashsets(struct exclude_list *el, struct exclude *x)
+{
+ struct exclude_entry *e;
+ char *truncated;
+ char *data = NULL;
+
+ if (!el->use_cone_patterns)
+ return;
+
+ if (x->patternlen >= 4 &&
+ !strcmp(x->pattern + x->patternlen - 4, "/*/*")) {
+ if (!(x->flags & EXC_FLAG_NEGATIVE)) {
+ /* Not a cone pattern. */
+ el->use_cone_patterns = 0;
+ warning(_("unrecognized pattern: '%s'"), x->pattern);
+ goto clear_hashmaps;
+ }
+
+ truncated = xstrdup(x->pattern);
+ truncated[x->patternlen - 4] = 0;
+
+ e = xmalloc(sizeof(struct exclude_entry));
+ e->pattern = truncated;
+ e->patternlen = x->patternlen - 4;
+ hashmap_entry_init(e, memhash(e->pattern, e->patternlen));
+
+ if (!hashmap_get(&el->recursive_hashmap, e, NULL)) {
+ /* We did not see the "parent" included */
+ warning(_("unrecognized negative pattern: '%s'"),
x->pattern);
+ free(truncated);
+ goto clear_hashmaps;
+ }
+
+ hashmap_add(&el->parent_hashmap, e);
+ hashmap_remove(&el->recursive_hashmap, e, &data);
+ free(data);
+ return;
+ }
+
+ if (x->patternlen >= 2 &&
+ !strcmp(x->pattern + x->patternlen - 2, "/*")) {
+ if (x->flags & EXC_FLAG_NEGATIVE) {
+ warning(_("unrecognized negative pattern: '%s'"),
x->pattern);
+ goto clear_hashmaps;
+ }
+
+ e = xmalloc(sizeof(struct exclude_entry));
+
+ truncated = xstrdup(x->pattern);
+ truncated[x->patternlen - 2] = 0;
+ e->pattern = truncated;
+ e->patternlen = x->patternlen - 2;
+ hashmap_entry_init(e, memhash(e->pattern, e->patternlen));
+
+ hashmap_add(&el->recursive_hashmap, e);
+
+ if (hashmap_get(&el->parent_hashmap, e, NULL)) {
+ /* we already included this at the parent level */
+ warning(_("your sparse-checkout file may have issues:
pattern '%s' is repeated"),
+ x->pattern);
+ hashmap_remove(&el->parent_hashmap, e, &data);
+ free(data);
+ }
+ return;
+ }
+
+clear_hashmaps:
+ hashmap_free(&el->parent_hashmap, 1);
+ hashmap_free(&el->recursive_hashmap, 1);
+ el->use_cone_patterns = 0;
+}
+
+static int hashmap_contains_path(struct hashmap *map,
+ struct strbuf *pattern)
+{
+ struct exclude_entry e;
+
+ /* Check straight mapping */
+ e.pattern = pattern->buf;
+ e.patternlen = pattern->len;
+ hashmap_entry_init(&e, memhash(e.pattern, e.patternlen));
+ return !!hashmap_get(map, &e, NULL);
+}
+
void add_exclude(const char *string, const char *base,
int baselen, struct exclude_list *el, int srcpos)
{
@@ -623,6 +716,8 @@ void add_exclude(const char *string, const char *base,
ALLOC_GROW(el->excludes, el->nr + 1, el->alloc);
el->excludes[el->nr++] = x;
x->el = el;
+
+ add_exclude_to_hashsets(el, x);
}
static int read_skip_worktree_file_from_index(const struct index_state *istate,
@@ -848,6 +943,10 @@ static int add_excludes_from_buffer(char *buf, size_t size,
int i, lineno = 1;
char *entry;
+ el->use_cone_patterns = core_sparse_checkout == SPARSE_CHECKOUT_CONE ?
1 : 0;
+ hashmap_init(&el->recursive_hashmap, el_hashmap_cmp, NULL, 0);
+ hashmap_init(&el->parent_hashmap, el_hashmap_cmp, NULL, 0);
+
el->filebuf = buf;
if (skip_utf8_bom(&buf, size))
@@ -1070,18 +1169,61 @@ static struct exclude
*last_exclude_matching_from_list(const char *pathname,
/*
* Scan the list and let the last match determine the fate.
- * Return 1 for exclude, 0 for include and -1 for undecided.
+ * Return 0 for exclude, 1 for include and -1 for undecided.
*/
int is_excluded_from_list(const char *pathname,
int pathlen, const char *basename, int *dtype,
struct exclude_list *el, struct index_state *istate)
{
struct exclude *exclude;
- exclude = last_exclude_matching_from_list(pathname, pathlen, basename,
- dtype, el, istate);
- if (exclude)
- return exclude->flags & EXC_FLAG_NEGATIVE ? 0 : 1;
- return -1; /* undecided */
+ struct strbuf parent_pathname = STRBUF_INIT;
+ int result = 0;
+ const char *slash_pos;
+
+ if (!el->use_cone_patterns) {
+ exclude = last_exclude_matching_from_list(pathname, pathlen,
basename,
+ dtype, el,
istate);
+
+ if (exclude)
+ return exclude->flags & EXC_FLAG_NEGATIVE ? 0 : 1;
+
+ return -1; /* undecided */
+ }
+
+ strbuf_addch(&parent_pathname, '/');
+ strbuf_add(&parent_pathname, pathname, pathlen);
+ slash_pos = strrchr(parent_pathname.buf, '/');
+
+ if (slash_pos == parent_pathname.buf) {
+ /* include every file in root */
+ result = 1;
+ goto done;
+ }
+
+ strbuf_setlen(&parent_pathname, slash_pos - parent_pathname.buf);
+
+ if (hashmap_contains_path(&el->parent_hashmap, &parent_pathname)) {
+ result = 1;
+ goto done;
+ }
+
+ while (parent_pathname.len) {
+ if (hashmap_contains_path(&el->recursive_hashmap,
+ &parent_pathname)) {
+ result = -1;
+ goto done;
+ }
+
+ slash_pos = strrchr(parent_pathname.buf, '/');
+ if (slash_pos == parent_pathname.buf)
+ break;
+
+ strbuf_setlen(&parent_pathname, slash_pos -
parent_pathname.buf);
+ }
+
+done:
+ strbuf_release(&parent_pathname);
+ return result;
}
static struct exclude *last_exclude_matching_from_lists(struct dir_struct *dir,
diff --git a/dir.h b/dir.h
index 680079bbe3..2d3356d1c0 100644
--- a/dir.h
+++ b/dir.h
@@ -4,6 +4,7 @@
/* See Documentation/technical/api-directory-listing.txt */
#include "cache.h"
+#include "hashmap.h"
#include "strbuf.h"
struct dir_entry {
@@ -37,6 +38,13 @@ struct exclude {
int srcpos;
};
+/* used for hashmaps for cone patterns */
+struct exclude_entry {
+ struct hashmap_entry ent;
+ char *pattern;
+ size_t patternlen;
+};
+
/*
* Each excludes file will be parsed into a fresh exclude_list which
* is appended to the relevant exclude_list_group (either EXC_DIRS or
@@ -55,6 +63,25 @@ struct exclude_list {
const char *src;
struct exclude **excludes;
+
+ /*
+ * While scanning the excludes, we attempt to match the patterns
+ * with a more restricted set that allows us to use hashsets for
+ * matching logic, which is faster than the linear lookup in the
+ * excludes array above. If non-zero, that check succeeded.
+ */
+ unsigned use_cone_patterns;
+
+ /*
+ * Stores paths where everything starting with those paths
+ * is included.
+ */
+ struct hashmap recursive_hashmap;
+
+ /*
+ * Used to check single-level parents of blobs.
+ */
+ struct hashmap parent_hashmap;
};
/*
diff --git a/t/t1091-sparse-checkout-builtin.sh
b/t/t1091-sparse-checkout-builtin.sh
index 8cc377b839..60f10864a1 100755
--- a/t/t1091-sparse-checkout-builtin.sh
+++ b/t/t1091-sparse-checkout-builtin.sh
@@ -134,6 +134,14 @@ test_expect_success 'cone mode: match patterns' '
test_cmp expect dir
'
+test_expect_success 'cone mode: warn on bad pattern' '
+ test_when_finished mv sparse-checkout repo/.git/info &&
+ cp repo/.git/info/sparse-checkout . &&
+ echo "!/deep/deeper/*" >>repo/.git/info/sparse-checkout &&
+ git -C repo read-tree -mu HEAD 2>err &&
+ test_i18ngrep "unrecognized negative pattern" err
+'
+
test_expect_success 'sparse-checkout disable' '
git -C repo sparse-checkout disable &&
test_path_is_missing repo/.git/info/sparse-checkout &&
--
gitgitgadget
