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#include "cache.h"
#include "split-index.h"
#include "ewah/ewok.h"
struct split_index *init_split_index(struct index_state *istate)
{
if (!istate->split_index) {
istate->split_index = xcalloc(1, sizeof(*istate->split_index));
istate->split_index->refcount = 1;
}
return istate->split_index;
}
int read_link_extension(struct index_state *istate,
const void *data_, unsigned long sz)
{
const unsigned char *data = data_;
struct split_index *si;
if (sz < 20)
return error("corrupt link extension (too short)");
si = init_split_index(istate);
hashcpy(si->base_sha1, data);
data += 20;
sz -= 20;
if (sz)
return error("garbage at the end of link extension");
return 0;
}
static int write_strbuf(void *user_data, const void *data, size_t len)
{
struct strbuf *sb = user_data;
strbuf_add(sb, data, len);
return len;
}
int write_link_extension(struct strbuf *sb,
struct index_state *istate)
{
struct split_index *si = istate->split_index;
strbuf_add(sb, si->base_sha1, 20);
if (!si->delete_bitmap && !si->replace_bitmap)
return 0;
ewah_serialize_to(si->delete_bitmap, write_strbuf, sb);
ewah_serialize_to(si->replace_bitmap, write_strbuf, sb);
return 0;
}
static void mark_base_index_entries(struct index_state *base)
{
int i;
/*
* To keep track of the shared entries between
* istate->base->cache[] and istate->cache[], base entry
* position is stored in each base entry. All positions start
* from 1 instead of 0, which is resrved to say "this is a new
* entry".
*/
for (i = 0; i < base->cache_nr; i++)
base->cache[i]->index = i + 1;
}
void merge_base_index(struct index_state *istate)
{
struct split_index *si = istate->split_index;
mark_base_index_entries(si->base);
istate->cache_nr = si->base->cache_nr;
ALLOC_GROW(istate->cache, istate->cache_nr, istate->cache_alloc);
memcpy(istate->cache, si->base->cache,
sizeof(*istate->cache) * istate->cache_nr);
}
void prepare_to_write_split_index(struct index_state *istate)
{
struct split_index *si = init_split_index(istate);
struct cache_entry **entries = NULL, *ce;
int i, nr_entries = 0, nr_alloc = 0;
si->delete_bitmap = ewah_new();
si->replace_bitmap = ewah_new();
if (si->base) {
/* Go through istate->cache[] and mark CE_MATCHED to
* entry with positive index. We'll go through
* base->cache[] later to delete all entries in base
* that are not marked eith either CE_MATCHED or
* CE_UPDATE_IN_BASE. If istate->cache[i] is a
* duplicate, deduplicate it.
*/
for (i = 0; i < istate->cache_nr; i++) {
struct cache_entry *base;
/* namelen is checked separately */
const unsigned int ondisk_flags =
CE_STAGEMASK | CE_VALID | CE_EXTENDED_FLAGS;
unsigned int ce_flags, base_flags, ret;
ce = istate->cache[i];
if (!ce->index)
continue;
if (ce->index > si->base->cache_nr) {
ce->index = 0;
continue;
}
ce->ce_flags |= CE_MATCHED; /* or "shared" */
base = si->base->cache[ce->index - 1];
if (ce == base)
continue;
if (ce->ce_namelen != base->ce_namelen ||
strcmp(ce->name, base->name)) {
ce->index = 0;
continue;
}
ce_flags = ce->ce_flags;
base_flags = base->ce_flags;
/* only on-disk flags matter */
ce->ce_flags &= ondisk_flags;
base->ce_flags &= ondisk_flags;
ret = memcmp(&ce->ce_stat_data, &base->ce_stat_data,
offsetof(struct cache_entry, name) -
offsetof(struct cache_entry, ce_stat_data));
ce->ce_flags = ce_flags;
base->ce_flags = base_flags;
if (ret)
ce->ce_flags |= CE_UPDATE_IN_BASE;
free(base);
si->base->cache[ce->index - 1] = ce;
}
for (i = 0; i < si->base->cache_nr; i++) {
ce = si->base->cache[i];
if ((ce->ce_flags & CE_REMOVE) ||
!(ce->ce_flags & CE_MATCHED))
ewah_set(si->delete_bitmap, i);
else if (ce->ce_flags & CE_UPDATE_IN_BASE) {
ewah_set(si->replace_bitmap, i);
ALLOC_GROW(entries, nr_entries+1, nr_alloc);
entries[nr_entries++] = ce;
}
}
}
for (i = 0; i < istate->cache_nr; i++) {
ce = istate->cache[i];
if ((!si->base || !ce->index) && !(ce->ce_flags & CE_REMOVE)) {
ALLOC_GROW(entries, nr_entries+1, nr_alloc);
entries[nr_entries++] = ce;
}
ce->ce_flags &= ~CE_MATCHED;
}
/*
* take cache[] out temporarily, put entries[] in its place
* for writing
*/
si->saved_cache = istate->cache;
si->saved_cache_nr = istate->cache_nr;
istate->cache = entries;
istate->cache_nr = nr_entries;
}
void finish_writing_split_index(struct index_state *istate)
{
struct split_index *si = init_split_index(istate);
ewah_free(si->delete_bitmap);
ewah_free(si->replace_bitmap);
si->delete_bitmap = NULL;
si->replace_bitmap = NULL;
free(istate->cache);
istate->cache = si->saved_cache;
istate->cache_nr = si->saved_cache_nr;
}
void discard_split_index(struct index_state *istate)
{
struct split_index *si = istate->split_index;
if (!si)
return;
istate->split_index = NULL;
si->refcount--;
if (si->refcount)
return;
if (si->base) {
discard_index(si->base);
free(si->base);
}
free(si);
}
void save_or_free_index_entry(struct index_state *istate, struct cache_entry *ce)
{
if (ce->index &&
istate->split_index &&
istate->split_index->base &&
ce->index <= istate->split_index->base->cache_nr &&
ce == istate->split_index->base->cache[ce->index - 1])
ce->ce_flags |= CE_REMOVE;
else
free(ce);
}
void replace_index_entry_in_base(struct index_state *istate,
struct cache_entry *old,
struct cache_entry *new)
{
if (old->index &&
istate->split_index &&
istate->split_index->base &&
old->index <= istate->split_index->base->cache_nr) {
new->index = old->index;
if (old != istate->split_index->base->cache[new->index - 1])
free(istate->split_index->base->cache[new->index - 1]);
istate->split_index->base->cache[new->index - 1] = new;
}
}
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