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![Ævar Arnfjörð Bjarmason](/assets/img/avatar_default.png)
When the "repo" member was added to "the_index" in [1] the repo_read_index() was made to populate it, but the unpopulated "the_index" variable didn't get the same treatment. Let's do that in initialize_the_repository() when we set it up, and likewise for all of the current callers initialized an empty "struct index_state". This simplifies code that needs to deal with "the_index" or a custom "struct index_state", we no longer need to second-guess this part of the "index_state" deep in the stack. A recent example of such second-guessing is the "istate->repo ? istate->repo : the_repository" code in [2]. We can now simply use "istate->repo". We're doing this by making use of the INDEX_STATE_INIT() macro (and corresponding function) added in [3], which now have mandatory "repo" arguments. Because we now call index_state_init() in repository.c's initialize_the_repository() we don't need to handle the case where we have a "repo->index" whose "repo" member doesn't match the "repo" we're setting up, i.e. the "Complete the double-reference" code in repo_read_index() being altered here. That logic was originally added in [1], and was working around the lack of what we now have in initialize_the_repository(). For "fsmonitor-settings.c" we can remove the initialization of a NULL "r" argument to "the_repository". This was added back in [4], and was needed at the time for callers that would pass us the "r" from an "istate->repo". Before this change such a change to "fsmonitor-settings.c" would segfault all over the test suite (e.g. in t0002-gitfile.sh). This change has wider eventual implications for "fsmonitor-settings.c". The reason the other lazy loading behavior in it is required (starting with "if (!r->settings.fsmonitor) ..." is because of the previously passed "r" being "NULL". I have other local changes on top of this which move its configuration reading to "prepare_repo_settings()" in "repo-settings.c", as we could now start to rely on it being called for our "r". But let's leave all of that for now, and narrowly remove this particular part of the lazy-loading. 1.1fd9ae517c
(repository: add repo reference to index_state, 2021-01-23) 2.ee1f0c242e
(read-cache: add index.skipHash config option, 2023-01-06) 3.2f6b1eb794
(cache API: add a "INDEX_STATE_INIT" macro/function, add release_index(), 2023-01-12) 4.1e0ea5c431
(fsmonitor: config settings are repository-specific, 2022-03-25) Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com> Acked-by: Derrick Stolee <derrickstolee@github.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
481 lines
14 KiB
C
481 lines
14 KiB
C
#include "cache.h"
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#include "split-index.h"
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#include "ewah/ewok.h"
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struct split_index *init_split_index(struct index_state *istate)
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{
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if (!istate->split_index) {
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if (istate->sparse_index)
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die(_("cannot use split index with a sparse index"));
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CALLOC_ARRAY(istate->split_index, 1);
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istate->split_index->refcount = 1;
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}
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return istate->split_index;
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}
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int read_link_extension(struct index_state *istate,
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const void *data_, unsigned long sz)
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{
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const unsigned char *data = data_;
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struct split_index *si;
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int ret;
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if (sz < the_hash_algo->rawsz)
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return error("corrupt link extension (too short)");
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si = init_split_index(istate);
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oidread(&si->base_oid, data);
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data += the_hash_algo->rawsz;
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sz -= the_hash_algo->rawsz;
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if (!sz)
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return 0;
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si->delete_bitmap = ewah_new();
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ret = ewah_read_mmap(si->delete_bitmap, data, sz);
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if (ret < 0)
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return error("corrupt delete bitmap in link extension");
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data += ret;
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sz -= ret;
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si->replace_bitmap = ewah_new();
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ret = ewah_read_mmap(si->replace_bitmap, data, sz);
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if (ret < 0)
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return error("corrupt replace bitmap in link extension");
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if (ret != sz)
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return error("garbage at the end of link extension");
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return 0;
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}
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int write_link_extension(struct strbuf *sb,
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struct index_state *istate)
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{
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struct split_index *si = istate->split_index;
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strbuf_add(sb, si->base_oid.hash, the_hash_algo->rawsz);
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if (!si->delete_bitmap && !si->replace_bitmap)
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return 0;
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ewah_serialize_strbuf(si->delete_bitmap, sb);
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ewah_serialize_strbuf(si->replace_bitmap, sb);
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return 0;
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}
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static void mark_base_index_entries(struct index_state *base)
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{
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int i;
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/*
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* To keep track of the shared entries between
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* istate->base->cache[] and istate->cache[], base entry
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* position is stored in each base entry. All positions start
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* from 1 instead of 0, which is reserved to say "this is a new
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* entry".
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*/
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for (i = 0; i < base->cache_nr; i++)
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base->cache[i]->index = i + 1;
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}
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void move_cache_to_base_index(struct index_state *istate)
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{
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struct split_index *si = istate->split_index;
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int i;
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/*
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* If there was a previous base index, then transfer ownership of allocated
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* entries to the parent index.
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*/
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if (si->base &&
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si->base->ce_mem_pool) {
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if (!istate->ce_mem_pool) {
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istate->ce_mem_pool = xmalloc(sizeof(struct mem_pool));
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mem_pool_init(istate->ce_mem_pool, 0);
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}
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mem_pool_combine(istate->ce_mem_pool, istate->split_index->base->ce_mem_pool);
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}
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ALLOC_ARRAY(si->base, 1);
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index_state_init(si->base, istate->repo);
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si->base->version = istate->version;
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/* zero timestamp disables racy test in ce_write_index() */
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si->base->timestamp = istate->timestamp;
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ALLOC_GROW(si->base->cache, istate->cache_nr, si->base->cache_alloc);
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si->base->cache_nr = istate->cache_nr;
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/*
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* The mem_pool needs to move with the allocated entries.
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*/
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si->base->ce_mem_pool = istate->ce_mem_pool;
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istate->ce_mem_pool = NULL;
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COPY_ARRAY(si->base->cache, istate->cache, istate->cache_nr);
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mark_base_index_entries(si->base);
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for (i = 0; i < si->base->cache_nr; i++)
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si->base->cache[i]->ce_flags &= ~CE_UPDATE_IN_BASE;
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}
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static void mark_entry_for_delete(size_t pos, void *data)
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{
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struct index_state *istate = data;
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if (pos >= istate->cache_nr)
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die("position for delete %d exceeds base index size %d",
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(int)pos, istate->cache_nr);
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istate->cache[pos]->ce_flags |= CE_REMOVE;
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istate->split_index->nr_deletions++;
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}
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static void replace_entry(size_t pos, void *data)
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{
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struct index_state *istate = data;
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struct split_index *si = istate->split_index;
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struct cache_entry *dst, *src;
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if (pos >= istate->cache_nr)
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die("position for replacement %d exceeds base index size %d",
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(int)pos, istate->cache_nr);
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if (si->nr_replacements >= si->saved_cache_nr)
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die("too many replacements (%d vs %d)",
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si->nr_replacements, si->saved_cache_nr);
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dst = istate->cache[pos];
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if (dst->ce_flags & CE_REMOVE)
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die("entry %d is marked as both replaced and deleted",
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(int)pos);
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src = si->saved_cache[si->nr_replacements];
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if (ce_namelen(src))
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die("corrupt link extension, entry %d should have "
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"zero length name", (int)pos);
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src->index = pos + 1;
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src->ce_flags |= CE_UPDATE_IN_BASE;
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src->ce_namelen = dst->ce_namelen;
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copy_cache_entry(dst, src);
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discard_cache_entry(src);
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si->nr_replacements++;
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}
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void merge_base_index(struct index_state *istate)
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{
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struct split_index *si = istate->split_index;
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unsigned int i;
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mark_base_index_entries(si->base);
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si->saved_cache = istate->cache;
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si->saved_cache_nr = istate->cache_nr;
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istate->cache_nr = si->base->cache_nr;
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istate->cache = NULL;
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istate->cache_alloc = 0;
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ALLOC_GROW(istate->cache, istate->cache_nr, istate->cache_alloc);
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COPY_ARRAY(istate->cache, si->base->cache, istate->cache_nr);
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si->nr_deletions = 0;
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si->nr_replacements = 0;
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ewah_each_bit(si->replace_bitmap, replace_entry, istate);
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ewah_each_bit(si->delete_bitmap, mark_entry_for_delete, istate);
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if (si->nr_deletions)
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remove_marked_cache_entries(istate, 0);
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for (i = si->nr_replacements; i < si->saved_cache_nr; i++) {
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if (!ce_namelen(si->saved_cache[i]))
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die("corrupt link extension, entry %d should "
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"have non-zero length name", i);
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add_index_entry(istate, si->saved_cache[i],
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ADD_CACHE_OK_TO_ADD |
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ADD_CACHE_KEEP_CACHE_TREE |
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/*
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* we may have to replay what
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* merge-recursive.c:update_stages()
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* does, which has this flag on
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*/
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ADD_CACHE_SKIP_DFCHECK);
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si->saved_cache[i] = NULL;
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}
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ewah_free(si->delete_bitmap);
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ewah_free(si->replace_bitmap);
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FREE_AND_NULL(si->saved_cache);
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si->delete_bitmap = NULL;
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si->replace_bitmap = NULL;
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si->saved_cache_nr = 0;
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}
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/*
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* Compare most of the fields in two cache entries, i.e. all except the
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* hashmap_entry and the name.
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*/
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static int compare_ce_content(struct cache_entry *a, struct cache_entry *b)
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{
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const unsigned int ondisk_flags = CE_STAGEMASK | CE_VALID |
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CE_EXTENDED_FLAGS;
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unsigned int ce_flags = a->ce_flags;
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unsigned int base_flags = b->ce_flags;
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int ret;
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/* only on-disk flags matter */
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a->ce_flags &= ondisk_flags;
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b->ce_flags &= ondisk_flags;
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ret = memcmp(&a->ce_stat_data, &b->ce_stat_data,
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offsetof(struct cache_entry, name) -
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offsetof(struct cache_entry, oid)) ||
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!oideq(&a->oid, &b->oid);
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a->ce_flags = ce_flags;
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b->ce_flags = base_flags;
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return ret;
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}
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void prepare_to_write_split_index(struct index_state *istate)
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{
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struct split_index *si = init_split_index(istate);
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struct cache_entry **entries = NULL, *ce;
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int i, nr_entries = 0, nr_alloc = 0;
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si->delete_bitmap = ewah_new();
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si->replace_bitmap = ewah_new();
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if (si->base) {
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/* Go through istate->cache[] and mark CE_MATCHED to
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* entry with positive index. We'll go through
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* base->cache[] later to delete all entries in base
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* that are not marked with either CE_MATCHED or
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* CE_UPDATE_IN_BASE. If istate->cache[i] is a
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* duplicate, deduplicate it.
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*/
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for (i = 0; i < istate->cache_nr; i++) {
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struct cache_entry *base;
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ce = istate->cache[i];
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if (!ce->index) {
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/*
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* During simple update index operations this
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* is a cache entry that is not present in
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* the shared index. It will be added to the
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* split index.
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*
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* However, it might also represent a file
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* that already has a cache entry in the
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* shared index, but a new index has just
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* been constructed by unpack_trees(), and
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* this entry now refers to different content
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* than what was recorded in the original
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* index, e.g. during 'read-tree -m HEAD^' or
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* 'checkout HEAD^'. In this case the
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* original entry in the shared index will be
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* marked as deleted, and this entry will be
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* added to the split index.
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*/
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continue;
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}
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if (ce->index > si->base->cache_nr) {
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BUG("ce refers to a shared ce at %d, which is beyond the shared index size %d",
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ce->index, si->base->cache_nr);
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}
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ce->ce_flags |= CE_MATCHED; /* or "shared" */
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base = si->base->cache[ce->index - 1];
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if (ce == base) {
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/* The entry is present in the shared index. */
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if (ce->ce_flags & CE_UPDATE_IN_BASE) {
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/*
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* Already marked for inclusion in
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* the split index, either because
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* the corresponding file was
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* modified and the cached stat data
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* was refreshed, or because there
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* is already a replacement entry in
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* the split index.
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* Nothing more to do here.
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*/
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} else if (!ce_uptodate(ce) &&
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is_racy_timestamp(istate, ce)) {
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/*
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* A racily clean cache entry stored
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* only in the shared index: it must
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* be added to the split index, so
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* the subsequent do_write_index()
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* can smudge its stat data.
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*/
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ce->ce_flags |= CE_UPDATE_IN_BASE;
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} else {
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/*
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* The entry is only present in the
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* shared index and it was not
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* refreshed.
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* Just leave it there.
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*/
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}
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continue;
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}
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if (ce->ce_namelen != base->ce_namelen ||
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strcmp(ce->name, base->name)) {
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ce->index = 0;
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continue;
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}
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/*
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* This is the copy of a cache entry that is present
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* in the shared index, created by unpack_trees()
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* while it constructed a new index.
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*/
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if (ce->ce_flags & CE_UPDATE_IN_BASE) {
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/*
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* Already marked for inclusion in the split
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* index, either because the corresponding
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* file was modified and the cached stat data
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* was refreshed, or because the original
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* entry already had a replacement entry in
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* the split index.
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* Nothing to do.
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*/
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} else if (!ce_uptodate(ce) &&
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is_racy_timestamp(istate, ce)) {
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/*
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* A copy of a racily clean cache entry from
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* the shared index. It must be added to
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* the split index, so the subsequent
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* do_write_index() can smudge its stat data.
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*/
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ce->ce_flags |= CE_UPDATE_IN_BASE;
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} else {
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/*
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* Thoroughly compare the cached data to see
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* whether it should be marked for inclusion
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* in the split index.
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*
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* This comparison might be unnecessary, as
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* code paths modifying the cached data do
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* set CE_UPDATE_IN_BASE as well.
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*/
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if (compare_ce_content(ce, base))
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ce->ce_flags |= CE_UPDATE_IN_BASE;
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}
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discard_cache_entry(base);
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si->base->cache[ce->index - 1] = ce;
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}
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for (i = 0; i < si->base->cache_nr; i++) {
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ce = si->base->cache[i];
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if ((ce->ce_flags & CE_REMOVE) ||
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!(ce->ce_flags & CE_MATCHED))
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ewah_set(si->delete_bitmap, i);
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else if (ce->ce_flags & CE_UPDATE_IN_BASE) {
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ewah_set(si->replace_bitmap, i);
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ce->ce_flags |= CE_STRIP_NAME;
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ALLOC_GROW(entries, nr_entries+1, nr_alloc);
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entries[nr_entries++] = ce;
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}
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if (is_null_oid(&ce->oid))
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istate->drop_cache_tree = 1;
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}
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}
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for (i = 0; i < istate->cache_nr; i++) {
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ce = istate->cache[i];
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if ((!si->base || !ce->index) && !(ce->ce_flags & CE_REMOVE)) {
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assert(!(ce->ce_flags & CE_STRIP_NAME));
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ALLOC_GROW(entries, nr_entries+1, nr_alloc);
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entries[nr_entries++] = ce;
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}
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ce->ce_flags &= ~CE_MATCHED;
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}
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/*
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* take cache[] out temporarily, put entries[] in its place
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* for writing
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*/
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si->saved_cache = istate->cache;
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si->saved_cache_nr = istate->cache_nr;
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istate->cache = entries;
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istate->cache_nr = nr_entries;
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}
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void finish_writing_split_index(struct index_state *istate)
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{
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struct split_index *si = init_split_index(istate);
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ewah_free(si->delete_bitmap);
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ewah_free(si->replace_bitmap);
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si->delete_bitmap = NULL;
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si->replace_bitmap = NULL;
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free(istate->cache);
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istate->cache = si->saved_cache;
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istate->cache_nr = si->saved_cache_nr;
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}
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void discard_split_index(struct index_state *istate)
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{
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struct split_index *si = istate->split_index;
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if (!si)
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return;
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istate->split_index = NULL;
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si->refcount--;
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if (si->refcount)
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return;
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if (si->base) {
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discard_index(si->base);
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free(si->base);
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}
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free(si);
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}
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void save_or_free_index_entry(struct index_state *istate, struct cache_entry *ce)
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{
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if (ce->index &&
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istate->split_index &&
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istate->split_index->base &&
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ce->index <= istate->split_index->base->cache_nr &&
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ce == istate->split_index->base->cache[ce->index - 1])
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ce->ce_flags |= CE_REMOVE;
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else
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discard_cache_entry(ce);
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}
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void replace_index_entry_in_base(struct index_state *istate,
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struct cache_entry *old_entry,
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struct cache_entry *new_entry)
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{
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if (old_entry->index &&
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istate->split_index &&
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istate->split_index->base &&
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old_entry->index <= istate->split_index->base->cache_nr) {
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new_entry->index = old_entry->index;
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if (old_entry != istate->split_index->base->cache[new_entry->index - 1])
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discard_cache_entry(istate->split_index->base->cache[new_entry->index - 1]);
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istate->split_index->base->cache[new_entry->index - 1] = new_entry;
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}
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}
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void add_split_index(struct index_state *istate)
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{
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if (!istate->split_index) {
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init_split_index(istate);
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istate->cache_changed |= SPLIT_INDEX_ORDERED;
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}
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}
|
|
|
|
void remove_split_index(struct index_state *istate)
|
|
{
|
|
if (istate->split_index) {
|
|
if (istate->split_index->base) {
|
|
/*
|
|
* When removing the split index, we need to move
|
|
* ownership of the mem_pool associated with the
|
|
* base index to the main index. There may be cache entries
|
|
* allocated from the base's memory pool that are shared with
|
|
* the_index.cache[].
|
|
*/
|
|
mem_pool_combine(istate->ce_mem_pool,
|
|
istate->split_index->base->ce_mem_pool);
|
|
|
|
/*
|
|
* The split index no longer owns the mem_pool backing
|
|
* its cache array. As we are discarding this index,
|
|
* mark the index as having no cache entries, so it
|
|
* will not attempt to clean up the cache entries or
|
|
* validate them.
|
|
*/
|
|
istate->split_index->base->cache_nr = 0;
|
|
}
|
|
|
|
/*
|
|
* We can discard the split index because its
|
|
* memory pool has been incorporated into the
|
|
* memory pool associated with the the_index.
|
|
*/
|
|
discard_split_index(istate);
|
|
|
|
istate->cache_changed |= SOMETHING_CHANGED;
|
|
}
|
|
}
|