Re: [PATCH 1/5] refs: store submodule ref stores in a hashmap
From: Junio C Hamano <hidden>
Date: 2017-02-09 22:24:42
Michael Haggerty [off-list ref] writes:
Aside from scaling better, this means that the submodule name needn't be stored in the ref_store instance anymore (which will be changed in a moment).
Nice. I like the latter reason very much (this is not a suggestion to change the description).
+struct submodule_hash_entry
+{
+ struct hashmap_entry ent; /* must be the first member! */
+
+ struct ref_store *refs;
+
+ /* NUL-terminated name of submodule: */
+ char submodule[FLEX_ARRAY];
+};
+
+static int submodule_hash_cmp(const void *entry, const void *entry_or_key,
+ const void *keydata)
+{
+ const struct submodule_hash_entry *e1 = entry, *e2 = entry_or_key;
+ const char *submodule = keydata;
+
+ return strcmp(e1->submodule, submodule ? submodule : e2->submodule);I would have found it more readable if it were like so: const char *submodule = keydata ? keydata : e2->submodule; return strcmp(e1->submodule, submodule); but I suspect the difference is not that huge.
+}
+
+static struct submodule_hash_entry *alloc_submodule_hash_entry(
+ const char *submodule, struct ref_store *refs)
+{
+ size_t len = strlen(submodule);
+ struct submodule_hash_entry *entry = malloc(sizeof(*entry) + len + 1);I think this (and the later memcpy) is what FLEX_ALLOC_MEM() was invented for.
quoted hunk
+ hashmap_entry_init(entry, strhash(submodule)); + entry->refs = refs; + memcpy(entry->submodule, submodule, len + 1); + return entry; +} ...@@ -1373,16 +1405,17 @@ void base_ref_store_init(struct ref_store *refs, die("BUG: main_ref_store initialized twice"); refs->submodule = ""; - refs->next = NULL; main_ref_store = refs; } else { - if (lookup_ref_store(submodule)) + refs->submodule = xstrdup(submodule); + + if (!submodule_ref_stores.tablesize) + hashmap_init(&submodule_ref_stores, submodule_hash_cmp, 20);
Makes me wonder what "20" stands for. Perhaps the caller should be allowed to say "I do not quite care what initial size is" by passing 0 or some equally but more clealy meaningless value (which of course would be outside the scope of this series).