describe is currently forced to look up the commit at each tag in
order to store the struct commit_name pointers in struct commit.util.
For --exact-match queries, those lookups are wasteful. In preparation
for removing them, put the commit_names into a hash table, indexed by
commit SHA1, that can be used to quickly check for exact matches.
Signed-off-by: Anders Kaseorg <andersk@xxxxxxxxxxx>
---
Change from v2.1: Use memcpy to avoid unaligned accesses in hash_sha1().
builtin/describe.c | 38 +++++++++++++++++++++++++++++++++-----
1 files changed, 33 insertions(+), 5 deletions(-)
diff --git a/builtin/describe.c b/builtin/describe.c
index 5b8461d..8149233 100644
--- a/builtin/describe.c
+++ b/builtin/describe.c
@@ -6,6 +6,7 @@
#include "exec_cmd.h"
#include "parse-options.h"
#include "diff.h"
+#include "hash.h"
#define SEEN (1u<<0)
#define MAX_TAGS (FLAG_BITS - 1)
@@ -22,7 +23,7 @@ static int tags; /* Allow lightweight tags */
static int longformat;
static int abbrev = DEFAULT_ABBREV;
static int max_candidates = 10;
-static int found_names;
+static struct hash_table names;
static const char *pattern;
static int always;
static const char *dirty;
@@ -34,6 +35,8 @@ static const char *diff_index_args[] = {
struct commit_name {
+ struct commit_name *next;
+ unsigned char peeled[20];
struct tag *tag;
unsigned prio:2; /* annotated tag = 2, tag = 1, head = 0 */
unsigned name_checked:1;
@@ -44,6 +47,21 @@ static const char *prio_names[] = {
"head", "lightweight", "annotated",
};
+static inline unsigned int hash_sha1(const unsigned char *sha1)
+{
+ unsigned int hash;
+ memcpy(&hash, sha1, sizeof(hash));
+ return hash;
+}
+
+static inline struct commit_name *find_commit_name(const unsigned char *peeled)
+{
+ struct commit_name *n = lookup_hash(hash_sha1(peeled), &names);
+ while (n && !!hashcmp(peeled, n->peeled))
+ n = n->next;
+ return n;
+}
+
static int replace_name(struct commit_name *e,
int prio,
const unsigned char *sha1,
@@ -82,12 +100,22 @@ static void add_to_known_names(const char *path,
int prio,
const unsigned char *sha1)
{
- struct commit_name *e = commit->util;
+ const unsigned char *peeled = commit->object.sha1;
+ struct commit_name *e = find_commit_name(peeled);
struct tag *tag = NULL;
if (replace_name(e, prio, sha1, &tag)) {
if (!e) {
+ void **pos;
e = xmalloc(sizeof(struct commit_name));
commit->util = e;
+ hashcpy(e->peeled, peeled);
+ pos = insert_hash(hash_sha1(peeled), e, &names);
+ if (pos) {
+ e->next = *pos;
+ *pos = e;
+ } else {
+ e->next = NULL;
+ }
}
e->tag = tag;
e->prio = prio;
@@ -95,7 +123,6 @@ static void add_to_known_names(const char *path,
hashcpy(e->sha1, sha1);
e->path = path;
}
- found_names = 1;
}
static int get_name(const char *path, const unsigned char *sha1, int flag, void *cb_data)
@@ -240,7 +267,7 @@ static void describe(const char *arg, int last_one)
if (!cmit)
die("%s is not a valid '%s' object", arg, commit_type);
- n = cmit->util;
+ n = find_commit_name(cmit->object.sha1);
if (n && (tags || all || n->prio == 2)) {
/*
* Exact match to an existing ref.
@@ -418,8 +445,9 @@ int cmd_describe(int argc, const char **argv, const char *prefix)
return cmd_name_rev(i + argc, args, prefix);
}
+ init_hash(&names);
for_each_rawref(get_name, NULL);
- if (!found_names && !always)
+ if (!names.nr && !always)
die("No names found, cannot describe anything.");
if (argc == 0) {
--
1.7.3.3
--
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