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fe446b01ae
The interface `cb_each()` iterates through a crit-bit tree and calls a specific callback function for each of the contained items. The callback function is expected to return either: - `CB_CONTINUE` in case iteration shall continue. - `CB_BREAK` to abort iteration. This is needlessly restrictive though, as callers may want to return arbitrary values and have them be bubbled up to the `cb_each()` call site. In fact, this is a rather common pattern we have: whenever such a callback function returns a non-zero error code, we abort iteration and bubble up the code as-is. Refactor both the crit-bit tree and oidtree subsystems to behave accordingly. Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>
111 lines
2.5 KiB
C
111 lines
2.5 KiB
C
/*
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* A wrapper around cbtree which stores oids
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* May be used to replace oid-array for prefix (abbreviation) matches
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*/
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#include "git-compat-util.h"
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#include "oidtree.h"
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#include "hash.h"
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void oidtree_init(struct oidtree *ot)
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{
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cb_init(&ot->tree);
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mem_pool_init(&ot->mem_pool, 0);
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}
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void oidtree_clear(struct oidtree *ot)
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{
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if (ot) {
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mem_pool_discard(&ot->mem_pool, 0);
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oidtree_init(ot);
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}
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}
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void oidtree_insert(struct oidtree *ot, const struct object_id *oid)
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{
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struct cb_node *on;
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struct object_id k;
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if (!oid->algo)
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BUG("oidtree_insert requires oid->algo");
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on = mem_pool_alloc(&ot->mem_pool, sizeof(*on) + sizeof(*oid));
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/*
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* Clear the padding and copy the result in separate steps to
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* respect the 4-byte alignment needed by struct object_id.
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*/
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oidcpy(&k, oid);
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memcpy(on->k, &k, sizeof(k));
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/*
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* n.b. Current callers won't get us duplicates, here. If a
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* future caller causes duplicates, there'll be a small leak
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* that won't be freed until oidtree_clear. Currently it's not
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* worth maintaining a free list
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*/
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cb_insert(&ot->tree, on, sizeof(*oid));
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}
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bool oidtree_contains(struct oidtree *ot, const struct object_id *oid)
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{
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struct object_id k;
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size_t klen = sizeof(k);
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oidcpy(&k, oid);
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if (oid->algo == GIT_HASH_UNKNOWN)
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klen -= sizeof(oid->algo);
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/* cb_lookup relies on memcmp on the struct, so order matters: */
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klen += BUILD_ASSERT_OR_ZERO(offsetof(struct object_id, hash) <
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offsetof(struct object_id, algo));
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return !!cb_lookup(&ot->tree, (const uint8_t *)&k, klen);
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}
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struct oidtree_each_data {
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oidtree_each_cb cb;
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void *cb_data;
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size_t *last_nibble_at;
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uint32_t algo;
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uint8_t last_byte;
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};
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static int iter(struct cb_node *n, void *cb_data)
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{
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struct oidtree_each_data *data = cb_data;
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struct object_id k;
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/* Copy to provide 4-byte alignment needed by struct object_id. */
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memcpy(&k, n->k, sizeof(k));
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if (data->algo != GIT_HASH_UNKNOWN && data->algo != k.algo)
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return 0;
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if (data->last_nibble_at) {
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if ((k.hash[*data->last_nibble_at] ^ data->last_byte) & 0xf0)
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return 0;
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}
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return data->cb(&k, data->cb_data);
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}
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int oidtree_each(struct oidtree *ot, const struct object_id *prefix,
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size_t prefix_hex_len, oidtree_each_cb cb, void *cb_data)
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{
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struct oidtree_each_data data = {
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.cb = cb,
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.cb_data = cb_data,
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.algo = prefix->algo,
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};
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size_t klen = prefix_hex_len / 2;
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assert(prefix_hex_len <= GIT_MAX_HEXSZ);
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if (prefix_hex_len & 1) {
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data.last_byte = prefix->hash[klen];
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data.last_nibble_at = &klen;
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}
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return cb_each(&ot->tree, prefix->hash, klen, iter, &data);
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}
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