On 8/25/2019 10:43 PM, Eric Wong wrote:
> This is a step towards removing the requirement for
> hashmap_entry being the first field of a struct.
>
> Signed-off-by: Eric Wong <e@xxxxxxxxx>
> ---
> diff.c | 19 ++++++++++++-------
> diffcore-rename.c | 11 +++++++----
> hashmap.c | 2 +-
> hashmap.h | 12 ++++++++----
> name-hash.c | 8 +++++---
> t/helper/test-hashmap.c | 10 ++++++----
> 6 files changed, 39 insertions(+), 23 deletions(-)
>
> diff --git a/diff.c b/diff.c
> index 72d3c6aa19..663b5d01f8 100644
> --- a/diff.c
> +++ b/diff.c
> @@ -1035,8 +1035,10 @@ static void pmb_advance_or_null_multi_match(struct diff_options *o,
> {
> int i;
> char *got_match = xcalloc(1, pmb_nr);
> + struct hashmap_entry *ent = &match->ent;
>
> - for (; match; match = hashmap_get_next(hm, &match->ent)) {
> + for (; ent; ent = hashmap_get_next(hm, ent)) {
> + match = container_of(ent, struct moved_entry, ent);
Lines like this are very difficult to parse. In this
container_of() macro, 'ent' is taking both the 'ptr' and
'member' values.
I would prefer that you make your local member be named
something different, for instance:
struct hashmap_entry *match_ent = &match->ent;
and
match = container_of(match_ent, struct moved_entry, ent);
> for (i = 0; i < pmb_nr; i++) {
> struct moved_entry *prev = pmb[i].match;
> struct moved_entry *cur = (prev && prev->next_line) ?
> @@ -1135,8 +1137,9 @@ static void mark_color_as_moved(struct diff_options *o,
>
> for (n = 0; n < o->emitted_symbols->nr; n++) {
> struct hashmap *hm = NULL;
> + struct hashmap_entry *ent = NULL;
> struct moved_entry *key;
> - struct moved_entry *match = NULL;
> + struct moved_entry *match;
> struct emitted_diff_symbol *l = &o->emitted_symbols->buf[n];
> enum diff_symbol last_symbol = 0;
>
> @@ -1144,20 +1147,20 @@ static void mark_color_as_moved(struct diff_options *o,
> case DIFF_SYMBOL_PLUS:
> hm = del_lines;
> key = prepare_entry(o, n);
> - match = hashmap_get(hm, &key->ent, NULL);
> + ent = hashmap_get(hm, &key->ent, NULL);
> free(key);
> break;
> case DIFF_SYMBOL_MINUS:
> hm = add_lines;
> key = prepare_entry(o, n);
> - match = hashmap_get(hm, &key->ent, NULL);
> + ent = hashmap_get(hm, &key->ent, NULL);
> free(key);
> break;
> default:
> flipped_block = 0;
> }
>
> - if (!match) {
> + if (!ent) {
> int i;
>
> adjust_last_block(o, n, block_length);
> @@ -1169,6 +1172,7 @@ static void mark_color_as_moved(struct diff_options *o,
> last_symbol = l->s;
> continue;
> }
> + match = container_of(ent, struct moved_entry, ent);
>
> if (o->color_moved == COLOR_MOVED_PLAIN) {
> last_symbol = l->s;
> @@ -1189,8 +1193,9 @@ static void mark_color_as_moved(struct diff_options *o,
> * The current line is the start of a new block.
> * Setup the set of potential blocks.
> */
> - for (; match; match = hashmap_get_next(hm,
> - &match->ent)) {
> + for (; ent; ent = hashmap_get_next(hm, ent)) {
> + match = container_of(ent, struct moved_entry,
> + ent);
Same complaint here.
> ALLOC_GROW(pmb, pmb_nr + 1, pmb_alloc);
> if (o->color_moved_ws_handling &
> COLOR_MOVED_WS_ALLOW_INDENTATION_CHANGE) {
> diff --git a/diffcore-rename.c b/diffcore-rename.c
> index 4670a40179..71aa240a68 100644
> --- a/diffcore-rename.c
> +++ b/diffcore-rename.c
> @@ -274,7 +274,7 @@ static int find_identical_files(struct hashmap *srcs,
> struct diff_options *options)
> {
> int renames = 0;
> -
> + struct hashmap_entry *ent;
> struct diff_filespec *target = rename_dst[dst_index].two;
> struct file_similarity *p, *best = NULL;
> int i = 100, best_score = -1;
> @@ -282,12 +282,15 @@ static int find_identical_files(struct hashmap *srcs,
> /*
> * Find the best source match for specified destination.
> */
> - p = hashmap_get_from_hash(srcs,
> + ent = hashmap_get_from_hash(srcs,
> hash_filespec(options->repo, target),
> NULL);
> - for (; p; p = hashmap_get_next(srcs, &p->entry)) {
> + for (; ent; ent = hashmap_get_next(srcs, ent)) {
> int score;
> - struct diff_filespec *source = p->filespec;
> + struct diff_filespec *source;
> +
> + p = container_of(ent, struct file_similarity, entry);
This is slightly better, but still a bit confusing.
> + source = p->filespec;
>
> /* False hash collision? */
> if (!oideq(&source->oid, &target->oid))
> diff --git a/hashmap.c b/hashmap.c
> index 2dd9912e13..d6434d9ca4 100644
> --- a/hashmap.c
> +++ b/hashmap.c
> @@ -192,7 +192,7 @@ void *hashmap_get(const struct hashmap *map, const struct hashmap_entry *key,
> return *find_entry_ptr(map, key, keydata);
> }
>
> -void *hashmap_get_next(const struct hashmap *map,
> +struct hashmap_entry *hashmap_get_next(const struct hashmap *map,
> const struct hashmap_entry *entry)
> {
> struct hashmap_entry *e = entry->next;
> diff --git a/hashmap.h b/hashmap.h
> index b62ee2e7b9..25643dcdc4 100644
> --- a/hashmap.h
> +++ b/hashmap.h
> @@ -55,15 +55,19 @@
> *
> * if (!strcmp("print_all_by_key", action)) {
> * struct long2string k, *e;
> + * struct hashmap_entry *ent;
> * hashmap_entry_init(&k->ent, memhash(&key, sizeof(long)));
> * k.key = key;
> *
> * flags &= ~COMPARE_VALUE;
> - * e = hashmap_get(&map, &k, NULL);
> - * if (e) {
> + * ent = hashmap_get(&map, &k, NULL);
> + * if (ent) {
> + * e = container_of(ent, struct long2string, ent);
> * printf("first: %ld %s\n", e->key, e->value);
> - * while ((e = hashmap_get_next(&map, e)))
> + * while ((ent = hashmap_get_next(&map, ent))) {
> + * e = container_of(ent, struct long2string, ent);
> * printf("found more: %ld %s\n", e->key, e->value);
> + * }
> * }
> * }
> *
> @@ -320,7 +324,7 @@ static inline void *hashmap_get_from_hash(const struct hashmap *map,
> * `entry` is the hashmap_entry to start the search from, obtained via a previous
> * call to `hashmap_get` or `hashmap_get_next`.
> */
> -void *hashmap_get_next(const struct hashmap *map,
> +struct hashmap_entry *hashmap_get_next(const struct hashmap *map,
> const struct hashmap_entry *entry);
>
> /*
> diff --git a/name-hash.c b/name-hash.c
> index f64c52bfa2..6f2779934f 100644
> --- a/name-hash.c
> +++ b/name-hash.c
> @@ -703,15 +703,17 @@ void adjust_dirname_case(struct index_state *istate, char *name)
> struct cache_entry *index_file_exists(struct index_state *istate, const char *name, int namelen, int icase)
> {
> struct cache_entry *ce;
> + struct hashmap_entry *ent;
>
> lazy_init_name_hash(istate);
>
> - ce = hashmap_get_from_hash(&istate->name_hash,
> + ent = hashmap_get_from_hash(&istate->name_hash,
> memihash(name, namelen), NULL);
> - while (ce) {
> + while (ent) {
> + ce = container_of(ent, struct cache_entry, ent);
> if (same_name(ce, name, namelen, icase))
> return ce;
> - ce = hashmap_get_next(&istate->name_hash, &ce->ent);
> + ent = hashmap_get_next(&istate->name_hash, ent);
> }
> return NULL;
> }
> diff --git a/t/helper/test-hashmap.c b/t/helper/test-hashmap.c
> index de2bd083b9..d85b8dc58e 100644
> --- a/t/helper/test-hashmap.c
> +++ b/t/helper/test-hashmap.c
> @@ -194,16 +194,18 @@ int cmd__hashmap(int argc, const char **argv)
> free(entry);
>
> } else if (!strcmp("get", cmd) && p1) {
> + struct hashmap_entry *e;
>
> /* lookup entry in hashmap */
> - entry = hashmap_get_from_hash(&map, hash, p1);
> + e = hashmap_get_from_hash(&map, hash, p1);
>
> /* print result */
> - if (!entry)
> + if (!e)
> puts("NULL");
> - while (entry) {
> + while (e) {
> + entry = container_of(e, struct test_entry, ent);
> puts(get_value(entry));
> - entry = hashmap_get_next(&map, &entry->ent);
> + e = hashmap_get_next(&map, e);
> }
>
> } else if (!strcmp("remove", cmd) && p1) {
I didn't comment on them all, but essentially every use of
container_of() here is pretty confusing with the names. Perhaps
some pattern of "type_member" could be helpful, so you can use
type_p = container_of(type_member, struct type, member);
to be really clear about each name.
Thanks,
-Stolee
