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![Jameson Miller](/assets/img/avatar_default.png)
It has been observed that the time spent loading an index with a large number of entries is partly dominated by malloc() calls. This change is in preparation for using memory pools to reduce the number of malloc() calls made to allocate cahce entries when loading an index. Add an API to allocate and discard cache entries, abstracting the details of managing the memory backing the cache entries. This commit does actually change how memory is managed - this will be done in a later commit in the series. This change makes the distinction between cache entries that are associated with an index and cache entries that are not associated with an index. A main use of cache entries is with an index, and we can optimize the memory management around this. We still have other cases where a cache entry is not persisted with an index, and so we need to handle the "transient" use case as well. To keep the congnitive overhead of managing the cache entries, there will only be a single discard function. This means there must be enough information kept with the cache entry so that we know how to discard them. A summary of the main functions in the API is: make_cache_entry: create cache entry for use in an index. Uses specified parameters to populate cache_entry fields. make_empty_cache_entry: Create an empty cache entry for use in an index. Returns cache entry with empty fields. make_transient_cache_entry: create cache entry that is not used in an index. Uses specified parameters to populate cache_entry fields. make_empty_transient_cache_entry: create cache entry that is not used in an index. Returns cache entry with empty fields. discard_cache_entry: A single function that knows how to discard a cache entry regardless of how it was allocated. Signed-off-by: Jameson Miller <jamill@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
196 lines
4.4 KiB
C
196 lines
4.4 KiB
C
#include "cache.h"
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#include "dir.h"
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#include "resolve-undo.h"
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#include "string-list.h"
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/* The only error case is to run out of memory in string-list */
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void record_resolve_undo(struct index_state *istate, struct cache_entry *ce)
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{
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struct string_list_item *lost;
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struct resolve_undo_info *ui;
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struct string_list *resolve_undo;
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int stage = ce_stage(ce);
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if (!stage)
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return;
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if (!istate->resolve_undo) {
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resolve_undo = xcalloc(1, sizeof(*resolve_undo));
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resolve_undo->strdup_strings = 1;
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istate->resolve_undo = resolve_undo;
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}
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resolve_undo = istate->resolve_undo;
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lost = string_list_insert(resolve_undo, ce->name);
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if (!lost->util)
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lost->util = xcalloc(1, sizeof(*ui));
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ui = lost->util;
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oidcpy(&ui->oid[stage - 1], &ce->oid);
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ui->mode[stage - 1] = ce->ce_mode;
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}
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void resolve_undo_write(struct strbuf *sb, struct string_list *resolve_undo)
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{
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struct string_list_item *item;
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for_each_string_list_item(item, resolve_undo) {
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struct resolve_undo_info *ui = item->util;
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int i;
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if (!ui)
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continue;
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strbuf_addstr(sb, item->string);
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strbuf_addch(sb, 0);
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for (i = 0; i < 3; i++)
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strbuf_addf(sb, "%o%c", ui->mode[i], 0);
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for (i = 0; i < 3; i++) {
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if (!ui->mode[i])
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continue;
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strbuf_add(sb, ui->oid[i].hash, the_hash_algo->rawsz);
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}
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}
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}
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struct string_list *resolve_undo_read(const char *data, unsigned long size)
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{
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struct string_list *resolve_undo;
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size_t len;
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char *endptr;
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int i;
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const unsigned rawsz = the_hash_algo->rawsz;
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resolve_undo = xcalloc(1, sizeof(*resolve_undo));
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resolve_undo->strdup_strings = 1;
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while (size) {
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struct string_list_item *lost;
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struct resolve_undo_info *ui;
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len = strlen(data) + 1;
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if (size <= len)
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goto error;
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lost = string_list_insert(resolve_undo, data);
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if (!lost->util)
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lost->util = xcalloc(1, sizeof(*ui));
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ui = lost->util;
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size -= len;
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data += len;
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for (i = 0; i < 3; i++) {
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ui->mode[i] = strtoul(data, &endptr, 8);
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if (!endptr || endptr == data || *endptr)
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goto error;
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len = (endptr + 1) - (char*)data;
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if (size <= len)
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goto error;
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size -= len;
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data += len;
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}
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for (i = 0; i < 3; i++) {
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if (!ui->mode[i])
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continue;
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if (size < rawsz)
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goto error;
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oidread(&ui->oid[i], (const unsigned char *)data);
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size -= rawsz;
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data += rawsz;
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}
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}
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return resolve_undo;
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error:
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string_list_clear(resolve_undo, 1);
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error("Index records invalid resolve-undo information");
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return NULL;
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}
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void resolve_undo_clear_index(struct index_state *istate)
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{
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struct string_list *resolve_undo = istate->resolve_undo;
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if (!resolve_undo)
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return;
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string_list_clear(resolve_undo, 1);
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free(resolve_undo);
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istate->resolve_undo = NULL;
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istate->cache_changed |= RESOLVE_UNDO_CHANGED;
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}
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int unmerge_index_entry_at(struct index_state *istate, int pos)
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{
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const struct cache_entry *ce;
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struct string_list_item *item;
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struct resolve_undo_info *ru;
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int i, err = 0, matched;
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char *name;
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if (!istate->resolve_undo)
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return pos;
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ce = istate->cache[pos];
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if (ce_stage(ce)) {
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/* already unmerged */
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while ((pos < istate->cache_nr) &&
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! strcmp(istate->cache[pos]->name, ce->name))
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pos++;
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return pos - 1; /* return the last entry processed */
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}
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item = string_list_lookup(istate->resolve_undo, ce->name);
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if (!item)
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return pos;
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ru = item->util;
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if (!ru)
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return pos;
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matched = ce->ce_flags & CE_MATCHED;
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name = xstrdup(ce->name);
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remove_index_entry_at(istate, pos);
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for (i = 0; i < 3; i++) {
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struct cache_entry *nce;
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if (!ru->mode[i])
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continue;
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nce = make_cache_entry(istate,
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ru->mode[i],
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&ru->oid[i],
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name, i + 1, 0);
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if (matched)
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nce->ce_flags |= CE_MATCHED;
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if (add_index_entry(istate, nce, ADD_CACHE_OK_TO_ADD)) {
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err = 1;
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error("cannot unmerge '%s'", name);
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}
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}
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free(name);
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if (err)
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return pos;
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free(ru);
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item->util = NULL;
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return unmerge_index_entry_at(istate, pos);
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}
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void unmerge_marked_index(struct index_state *istate)
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{
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int i;
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if (!istate->resolve_undo)
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return;
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for (i = 0; i < istate->cache_nr; i++) {
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const struct cache_entry *ce = istate->cache[i];
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if (ce->ce_flags & CE_MATCHED)
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i = unmerge_index_entry_at(istate, i);
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}
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}
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void unmerge_index(struct index_state *istate, const struct pathspec *pathspec)
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{
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int i;
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if (!istate->resolve_undo)
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return;
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for (i = 0; i < istate->cache_nr; i++) {
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const struct cache_entry *ce = istate->cache[i];
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if (!ce_path_match(ce, pathspec, NULL))
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continue;
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i = unmerge_index_entry_at(istate, i);
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}
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}
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