From 2834bc27c16e4ae103768dd6dda530f0e46116af Mon Sep 17 00:00:00 2001 From: Vicent Marti Date: Thu, 24 Oct 2013 14:01:06 -0400 Subject: [PATCH] pack-objects: refactor the packing list The hash table that stores the packing list for a given `pack-objects` run was tightly coupled to the pack-objects code. In this commit, we refactor the hash table and the underlying storage array into a `packing_data` struct. The functionality for accessing and adding entries to the packing list is hence accessible from other parts of Git besides the `pack-objects` builtin. This refactoring is a requirement for further patches in this series that will require accessing the commit packing list from outside of `pack-objects`. The hash table implementation has been minimally altered: we now use table sizes which are always a power of two, to ensure a uniform index distribution in the array. Signed-off-by: Vicent Marti Signed-off-by: Jeff King Signed-off-by: Junio C Hamano --- Makefile | 2 + builtin/pack-objects.c | 175 ++++++++++------------------------------- pack-objects.c | 111 ++++++++++++++++++++++++++ pack-objects.h | 47 +++++++++++ 4 files changed, 200 insertions(+), 135 deletions(-) create mode 100644 pack-objects.c create mode 100644 pack-objects.h diff --git a/Makefile b/Makefile index af847f8468..48ff0bdb18 100644 --- a/Makefile +++ b/Makefile @@ -694,6 +694,7 @@ LIB_H += notes-merge.h LIB_H += notes-utils.h LIB_H += notes.h LIB_H += object.h +LIB_H += pack-objects.h LIB_H += pack-revindex.h LIB_H += pack.h LIB_H += parse-options.h @@ -831,6 +832,7 @@ LIB_OBJS += notes-merge.o LIB_OBJS += notes-utils.o LIB_OBJS += object.o LIB_OBJS += pack-check.o +LIB_OBJS += pack-objects.o LIB_OBJS += pack-revindex.o LIB_OBJS += pack-write.o LIB_OBJS += pager.o diff --git a/builtin/pack-objects.c b/builtin/pack-objects.c index 36273dd6f0..f3f0cf95a8 100644 --- a/builtin/pack-objects.c +++ b/builtin/pack-objects.c @@ -14,6 +14,7 @@ #include "diff.h" #include "revision.h" #include "list-objects.h" +#include "pack-objects.h" #include "progress.h" #include "refs.h" #include "streaming.h" @@ -25,42 +26,15 @@ static const char *pack_usage[] = { NULL }; -struct object_entry { - struct pack_idx_entry idx; - unsigned long size; /* uncompressed size */ - struct packed_git *in_pack; /* already in pack */ - off_t in_pack_offset; - struct object_entry *delta; /* delta base object */ - struct object_entry *delta_child; /* deltified objects who bases me */ - struct object_entry *delta_sibling; /* other deltified objects who - * uses the same base as me - */ - void *delta_data; /* cached delta (uncompressed) */ - unsigned long delta_size; /* delta data size (uncompressed) */ - unsigned long z_delta_size; /* delta data size (compressed) */ - enum object_type type; - enum object_type in_pack_type; /* could be delta */ - uint32_t hash; /* name hint hash */ - unsigned char in_pack_header_size; - unsigned preferred_base:1; /* - * we do not pack this, but is available - * to be used as the base object to delta - * objects against. - */ - unsigned no_try_delta:1; - unsigned tagged:1; /* near the very tip of refs */ - unsigned filled:1; /* assigned write-order */ -}; - /* - * Objects we are going to pack are collected in objects array (dynamically - * expanded). nr_objects & nr_alloc controls this array. They are stored - * in the order we see -- typically rev-list --objects order that gives us - * nice "minimum seek" order. + * Objects we are going to pack are collected in the `to_pack` structure. + * It contains an array (dynamically expanded) of the object data, and a map + * that can resolve SHA1s to their position in the array. */ -static struct object_entry *objects; +static struct packing_data to_pack; + static struct pack_idx_entry **written_list; -static uint32_t nr_objects, nr_alloc, nr_result, nr_written; +static uint32_t nr_result, nr_written; static int non_empty; static int reuse_delta = 1, reuse_object = 1; @@ -89,22 +63,12 @@ static unsigned long cache_max_small_delta_size = 1000; static unsigned long window_memory_limit = 0; -/* - * The object names in objects array are hashed with this hashtable, - * to help looking up the entry by object name. - * This hashtable is built after all the objects are seen. - */ -static int *object_ix; -static int object_ix_hashsz; -static struct object_entry *locate_object_entry(const unsigned char *sha1); - /* * stats */ static uint32_t written, written_delta; static uint32_t reused, reused_delta; - static void *get_delta(struct object_entry *entry) { unsigned long size, base_size, delta_size; @@ -553,12 +517,12 @@ static int mark_tagged(const char *path, const unsigned char *sha1, int flag, void *cb_data) { unsigned char peeled[20]; - struct object_entry *entry = locate_object_entry(sha1); + struct object_entry *entry = packlist_find(&to_pack, sha1, NULL); if (entry) entry->tagged = 1; if (!peel_ref(path, peeled)) { - entry = locate_object_entry(peeled); + entry = packlist_find(&to_pack, peeled, NULL); if (entry) entry->tagged = 1; } @@ -633,9 +597,10 @@ static struct object_entry **compute_write_order(void) { unsigned int i, wo_end, last_untagged; - struct object_entry **wo = xmalloc(nr_objects * sizeof(*wo)); + struct object_entry **wo = xmalloc(to_pack.nr_objects * sizeof(*wo)); + struct object_entry *objects = to_pack.objects; - for (i = 0; i < nr_objects; i++) { + for (i = 0; i < to_pack.nr_objects; i++) { objects[i].tagged = 0; objects[i].filled = 0; objects[i].delta_child = NULL; @@ -647,7 +612,7 @@ static struct object_entry **compute_write_order(void) * Make sure delta_sibling is sorted in the original * recency order. */ - for (i = nr_objects; i > 0;) { + for (i = to_pack.nr_objects; i > 0;) { struct object_entry *e = &objects[--i]; if (!e->delta) continue; @@ -665,7 +630,7 @@ static struct object_entry **compute_write_order(void) * Give the objects in the original recency order until * we see a tagged tip. */ - for (i = wo_end = 0; i < nr_objects; i++) { + for (i = wo_end = 0; i < to_pack.nr_objects; i++) { if (objects[i].tagged) break; add_to_write_order(wo, &wo_end, &objects[i]); @@ -675,7 +640,7 @@ static struct object_entry **compute_write_order(void) /* * Then fill all the tagged tips. */ - for (; i < nr_objects; i++) { + for (; i < to_pack.nr_objects; i++) { if (objects[i].tagged) add_to_write_order(wo, &wo_end, &objects[i]); } @@ -683,7 +648,7 @@ static struct object_entry **compute_write_order(void) /* * And then all remaining commits and tags. */ - for (i = last_untagged; i < nr_objects; i++) { + for (i = last_untagged; i < to_pack.nr_objects; i++) { if (objects[i].type != OBJ_COMMIT && objects[i].type != OBJ_TAG) continue; @@ -693,7 +658,7 @@ static struct object_entry **compute_write_order(void) /* * And then all the trees. */ - for (i = last_untagged; i < nr_objects; i++) { + for (i = last_untagged; i < to_pack.nr_objects; i++) { if (objects[i].type != OBJ_TREE) continue; add_to_write_order(wo, &wo_end, &objects[i]); @@ -702,13 +667,13 @@ static struct object_entry **compute_write_order(void) /* * Finally all the rest in really tight order */ - for (i = last_untagged; i < nr_objects; i++) { + for (i = last_untagged; i < to_pack.nr_objects; i++) { if (!objects[i].filled) add_family_to_write_order(wo, &wo_end, &objects[i]); } - if (wo_end != nr_objects) - die("ordered %u objects, expected %"PRIu32, wo_end, nr_objects); + if (wo_end != to_pack.nr_objects) + die("ordered %u objects, expected %"PRIu32, wo_end, to_pack.nr_objects); return wo; } @@ -724,7 +689,7 @@ static void write_pack_file(void) if (progress > pack_to_stdout) progress_state = start_progress("Writing objects", nr_result); - written_list = xmalloc(nr_objects * sizeof(*written_list)); + written_list = xmalloc(to_pack.nr_objects * sizeof(*written_list)); write_order = compute_write_order(); do { @@ -740,7 +705,7 @@ static void write_pack_file(void) if (!offset) die_errno("unable to write pack header"); nr_written = 0; - for (; i < nr_objects; i++) { + for (; i < to_pack.nr_objects; i++) { struct object_entry *e = write_order[i]; if (write_one(f, e, &offset) == WRITE_ONE_BREAK) break; @@ -803,7 +768,7 @@ static void write_pack_file(void) written_list[j]->offset = (off_t)-1; } nr_remaining -= nr_written; - } while (nr_remaining && i < nr_objects); + } while (nr_remaining && i < to_pack.nr_objects); free(written_list); free(write_order); @@ -813,53 +778,6 @@ static void write_pack_file(void) written, nr_result); } -static int locate_object_entry_hash(const unsigned char *sha1) -{ - int i; - unsigned int ui; - memcpy(&ui, sha1, sizeof(unsigned int)); - i = ui % object_ix_hashsz; - while (0 < object_ix[i]) { - if (!hashcmp(sha1, objects[object_ix[i] - 1].idx.sha1)) - return i; - if (++i == object_ix_hashsz) - i = 0; - } - return -1 - i; -} - -static struct object_entry *locate_object_entry(const unsigned char *sha1) -{ - int i; - - if (!object_ix_hashsz) - return NULL; - - i = locate_object_entry_hash(sha1); - if (0 <= i) - return &objects[object_ix[i]-1]; - return NULL; -} - -static void rehash_objects(void) -{ - uint32_t i; - struct object_entry *oe; - - object_ix_hashsz = nr_objects * 3; - if (object_ix_hashsz < 1024) - object_ix_hashsz = 1024; - object_ix = xrealloc(object_ix, sizeof(int) * object_ix_hashsz); - memset(object_ix, 0, sizeof(int) * object_ix_hashsz); - for (i = 0, oe = objects; i < nr_objects; i++, oe++) { - int ix = locate_object_entry_hash(oe->idx.sha1); - if (0 <= ix) - continue; - ix = -1 - ix; - object_ix[ix] = i + 1; - } -} - static uint32_t name_hash(const char *name) { uint32_t c, hash = 0; @@ -908,13 +826,12 @@ static int add_object_entry(const unsigned char *sha1, enum object_type type, struct object_entry *entry; struct packed_git *p, *found_pack = NULL; off_t found_offset = 0; - int ix; uint32_t hash = name_hash(name); + uint32_t index_pos; - ix = nr_objects ? locate_object_entry_hash(sha1) : -1; - if (ix >= 0) { + entry = packlist_find(&to_pack, sha1, &index_pos); + if (entry) { if (exclude) { - entry = objects + object_ix[ix] - 1; if (!entry->preferred_base) nr_result--; entry->preferred_base = 1; @@ -947,14 +864,7 @@ static int add_object_entry(const unsigned char *sha1, enum object_type type, } } - if (nr_objects >= nr_alloc) { - nr_alloc = (nr_alloc + 1024) * 3 / 2; - objects = xrealloc(objects, nr_alloc * sizeof(*entry)); - } - - entry = objects + nr_objects++; - memset(entry, 0, sizeof(*entry)); - hashcpy(entry->idx.sha1, sha1); + entry = packlist_alloc(&to_pack, sha1, index_pos); entry->hash = hash; if (type) entry->type = type; @@ -967,12 +877,7 @@ static int add_object_entry(const unsigned char *sha1, enum object_type type, entry->in_pack_offset = found_offset; } - if (object_ix_hashsz * 3 <= nr_objects * 4) - rehash_objects(); - else - object_ix[-1 - ix] = nr_objects; - - display_progress(progress_state, nr_objects); + display_progress(progress_state, to_pack.nr_objects); if (name && no_try_delta(name)) entry->no_try_delta = 1; @@ -1329,7 +1234,7 @@ static void check_object(struct object_entry *entry) break; } - if (base_ref && (base_entry = locate_object_entry(base_ref))) { + if (base_ref && (base_entry = packlist_find(&to_pack, base_ref, NULL))) { /* * If base_ref was set above that means we wish to * reuse delta data, and we even found that base @@ -1403,12 +1308,12 @@ static void get_object_details(void) uint32_t i; struct object_entry **sorted_by_offset; - sorted_by_offset = xcalloc(nr_objects, sizeof(struct object_entry *)); - for (i = 0; i < nr_objects; i++) - sorted_by_offset[i] = objects + i; - qsort(sorted_by_offset, nr_objects, sizeof(*sorted_by_offset), pack_offset_sort); + sorted_by_offset = xcalloc(to_pack.nr_objects, sizeof(struct object_entry *)); + for (i = 0; i < to_pack.nr_objects; i++) + sorted_by_offset[i] = to_pack.objects + i; + qsort(sorted_by_offset, to_pack.nr_objects, sizeof(*sorted_by_offset), pack_offset_sort); - for (i = 0; i < nr_objects; i++) { + for (i = 0; i < to_pack.nr_objects; i++) { struct object_entry *entry = sorted_by_offset[i]; check_object(entry); if (big_file_threshold < entry->size) @@ -2034,7 +1939,7 @@ static int add_ref_tag(const char *path, const unsigned char *sha1, int flag, vo if (!prefixcmp(path, "refs/tags/") && /* is a tag? */ !peel_ref(path, peeled) && /* peelable? */ - locate_object_entry(peeled)) /* object packed? */ + packlist_find(&to_pack, peeled, NULL)) /* object packed? */ add_object_entry(sha1, OBJ_TAG, NULL, 0); return 0; } @@ -2057,14 +1962,14 @@ static void prepare_pack(int window, int depth) if (!pack_to_stdout) do_check_packed_object_crc = 1; - if (!nr_objects || !window || !depth) + if (!to_pack.nr_objects || !window || !depth) return; - delta_list = xmalloc(nr_objects * sizeof(*delta_list)); + delta_list = xmalloc(to_pack.nr_objects * sizeof(*delta_list)); nr_deltas = n = 0; - for (i = 0; i < nr_objects; i++) { - struct object_entry *entry = objects + i; + for (i = 0; i < to_pack.nr_objects; i++) { + struct object_entry *entry = to_pack.objects + i; if (entry->delta) /* This happens if we decided to reuse existing @@ -2342,7 +2247,7 @@ static void loosen_unused_packed_objects(struct rev_info *revs) for (i = 0; i < p->num_objects; i++) { sha1 = nth_packed_object_sha1(p, i); - if (!locate_object_entry(sha1) && + if (!packlist_find(&to_pack, sha1, NULL) && !has_sha1_pack_kept_or_nonlocal(sha1)) if (force_object_loose(sha1, p->mtime)) die("unable to force loose object"); diff --git a/pack-objects.c b/pack-objects.c new file mode 100644 index 0000000000..d01d851ce9 --- /dev/null +++ b/pack-objects.c @@ -0,0 +1,111 @@ +#include "cache.h" +#include "object.h" +#include "pack.h" +#include "pack-objects.h" + +static uint32_t locate_object_entry_hash(struct packing_data *pdata, + const unsigned char *sha1, + int *found) +{ + uint32_t i, hash, mask = (pdata->index_size - 1); + + memcpy(&hash, sha1, sizeof(uint32_t)); + i = hash & mask; + + while (pdata->index[i] > 0) { + uint32_t pos = pdata->index[i] - 1; + + if (!hashcmp(sha1, pdata->objects[pos].idx.sha1)) { + *found = 1; + return i; + } + + i = (i + 1) & mask; + } + + *found = 0; + return i; +} + +static inline uint32_t closest_pow2(uint32_t v) +{ + v = v - 1; + v |= v >> 1; + v |= v >> 2; + v |= v >> 4; + v |= v >> 8; + v |= v >> 16; + return v + 1; +} + +static void rehash_objects(struct packing_data *pdata) +{ + uint32_t i; + struct object_entry *entry; + + pdata->index_size = closest_pow2(pdata->nr_objects * 3); + if (pdata->index_size < 1024) + pdata->index_size = 1024; + + pdata->index = xrealloc(pdata->index, sizeof(uint32_t) * pdata->index_size); + memset(pdata->index, 0, sizeof(int) * pdata->index_size); + + entry = pdata->objects; + + for (i = 0; i < pdata->nr_objects; i++) { + int found; + uint32_t ix = locate_object_entry_hash(pdata, entry->idx.sha1, &found); + + if (found) + die("BUG: Duplicate object in hash"); + + pdata->index[ix] = i + 1; + entry++; + } +} + +struct object_entry *packlist_find(struct packing_data *pdata, + const unsigned char *sha1, + uint32_t *index_pos) +{ + uint32_t i; + int found; + + if (!pdata->index_size) + return NULL; + + i = locate_object_entry_hash(pdata, sha1, &found); + + if (index_pos) + *index_pos = i; + + if (!found) + return NULL; + + return &pdata->objects[pdata->index[i] - 1]; +} + +struct object_entry *packlist_alloc(struct packing_data *pdata, + const unsigned char *sha1, + uint32_t index_pos) +{ + struct object_entry *new_entry; + + if (pdata->nr_objects >= pdata->nr_alloc) { + pdata->nr_alloc = (pdata->nr_alloc + 1024) * 3 / 2; + pdata->objects = xrealloc(pdata->objects, + pdata->nr_alloc * sizeof(*new_entry)); + } + + new_entry = pdata->objects + pdata->nr_objects++; + + memset(new_entry, 0, sizeof(*new_entry)); + hashcpy(new_entry->idx.sha1, sha1); + + if (pdata->index_size * 3 <= pdata->nr_objects * 4) + rehash_objects(pdata); + else + pdata->index[index_pos] = pdata->nr_objects; + + return new_entry; +} diff --git a/pack-objects.h b/pack-objects.h new file mode 100644 index 0000000000..f5282155f2 --- /dev/null +++ b/pack-objects.h @@ -0,0 +1,47 @@ +#ifndef PACK_OBJECTS_H +#define PACK_OBJECTS_H + +struct object_entry { + struct pack_idx_entry idx; + unsigned long size; /* uncompressed size */ + struct packed_git *in_pack; /* already in pack */ + off_t in_pack_offset; + struct object_entry *delta; /* delta base object */ + struct object_entry *delta_child; /* deltified objects who bases me */ + struct object_entry *delta_sibling; /* other deltified objects who + * uses the same base as me + */ + void *delta_data; /* cached delta (uncompressed) */ + unsigned long delta_size; /* delta data size (uncompressed) */ + unsigned long z_delta_size; /* delta data size (compressed) */ + enum object_type type; + enum object_type in_pack_type; /* could be delta */ + uint32_t hash; /* name hint hash */ + unsigned char in_pack_header_size; + unsigned preferred_base:1; /* + * we do not pack this, but is available + * to be used as the base object to delta + * objects against. + */ + unsigned no_try_delta:1; + unsigned tagged:1; /* near the very tip of refs */ + unsigned filled:1; /* assigned write-order */ +}; + +struct packing_data { + struct object_entry *objects; + uint32_t nr_objects, nr_alloc; + + int32_t *index; + uint32_t index_size; +}; + +struct object_entry *packlist_alloc(struct packing_data *pdata, + const unsigned char *sha1, + uint32_t index_pos); + +struct object_entry *packlist_find(struct packing_data *pdata, + const unsigned char *sha1, + uint32_t *index_pos); + +#endif