Merge branch 'jk/pack-revindex'

In-core storage of the reverse index for .pack files (which lets
you go from a pack offset to an object name) has been streamlined.

* jk/pack-revindex:
  pack-revindex: store entries directly in packed_git
  pack-revindex: drop hash table
This commit is contained in:
Junio C Hamano 2016-01-20 11:43:22 -08:00
commit 4fd1359158
4 changed files with 35 additions and 90 deletions

View file

@ -9,6 +9,7 @@
#include "convert.h"
#include "trace.h"
#include "string-list.h"
#include "pack-revindex.h"
#include SHA1_HEADER
#ifndef platform_SHA_CTX
@ -1299,6 +1300,7 @@ extern struct packed_git {
freshened:1,
do_not_close:1;
unsigned char sha1[20];
struct revindex_entry *revindex;
/* something like ".git/objects/pack/xxxxx.pack" */
char pack_name[FLEX_ARRAY]; /* more */
} *packed_git;

View file

@ -33,9 +33,6 @@ static struct bitmap_index {
/* Packfile to which this bitmap index belongs to */
struct packed_git *pack;
/* reverse index for the packfile */
struct pack_revindex *reverse_index;
/*
* Mark the first `reuse_objects` in the packfile as reused:
* they will be sent as-is without using them for repacking
@ -308,7 +305,7 @@ static int load_pack_bitmap(void)
bitmap_git.bitmaps = kh_init_sha1();
bitmap_git.ext_index.positions = kh_init_sha1_pos();
bitmap_git.reverse_index = revindex_for_pack(bitmap_git.pack);
load_pack_revindex(bitmap_git.pack);
if (!(bitmap_git.commits = read_bitmap_1(&bitmap_git)) ||
!(bitmap_git.trees = read_bitmap_1(&bitmap_git)) ||
@ -380,7 +377,7 @@ static inline int bitmap_position_packfile(const unsigned char *sha1)
if (!offset)
return -1;
return find_revindex_position(bitmap_git.reverse_index, offset);
return find_revindex_position(bitmap_git.pack, offset);
}
static int bitmap_position(const unsigned char *sha1)
@ -630,7 +627,7 @@ static void show_objects_for_type(
if (pos + offset < bitmap_git.reuse_objects)
continue;
entry = &bitmap_git.reverse_index->revindex[pos + offset];
entry = &bitmap_git.pack->revindex[pos + offset];
sha1 = nth_packed_object_sha1(bitmap_git.pack, entry->nr);
if (bitmap_git.hashes)
@ -804,7 +801,7 @@ int reuse_partial_packfile_from_bitmap(struct packed_git **packfile,
return -1;
bitmap_git.reuse_objects = *entries = reuse_objects;
*up_to = bitmap_git.reverse_index->revindex[reuse_objects].offset;
*up_to = bitmap_git.pack->revindex[reuse_objects].offset;
*packfile = bitmap_git.pack;
return 0;
@ -1038,7 +1035,7 @@ int rebuild_existing_bitmaps(struct packing_data *mapping,
struct revindex_entry *entry;
struct object_entry *oe;
entry = &bitmap_git.reverse_index->revindex[i];
entry = &bitmap_git.pack->revindex[i];
sha1 = nth_packed_object_sha1(bitmap_git.pack, entry->nr);
oe = packlist_find(mapping, sha1, NULL);

View file

@ -8,52 +8,13 @@
* size is easily available by examining the pack entry header). It is
* also rather expensive to find the sha1 for an object given its offset.
*
* We build a hashtable of existing packs (pack_revindex), and keep reverse
* index here -- pack index file is sorted by object name mapping to offset;
* this pack_revindex[].revindex array is a list of offset/index_nr pairs
* The pack index file is sorted by object name mapping to offset;
* this revindex array is a list of offset/index_nr pairs
* ordered by offset, so if you know the offset of an object, next offset
* is where its packed representation ends and the index_nr can be used to
* get the object sha1 from the main index.
*/
static struct pack_revindex *pack_revindex;
static int pack_revindex_hashsz;
static int pack_revindex_ix(struct packed_git *p)
{
unsigned long ui = (unsigned long)(intptr_t)p;
int i;
ui = ui ^ (ui >> 16); /* defeat structure alignment */
i = (int)(ui % pack_revindex_hashsz);
while (pack_revindex[i].p) {
if (pack_revindex[i].p == p)
return i;
if (++i == pack_revindex_hashsz)
i = 0;
}
return -1 - i;
}
static void init_pack_revindex(void)
{
int num;
struct packed_git *p;
for (num = 0, p = packed_git; p; p = p->next)
num++;
if (!num)
return;
pack_revindex_hashsz = num * 11;
pack_revindex = xcalloc(pack_revindex_hashsz, sizeof(*pack_revindex));
for (p = packed_git; p; p = p->next) {
num = pack_revindex_ix(p);
num = - 1 - num;
pack_revindex[num].p = p;
}
/* revindex elements are lazily initialized */
}
/*
* This is a least-significant-digit radix sort.
*
@ -154,14 +115,13 @@ static void sort_revindex(struct revindex_entry *entries, unsigned n, off_t max)
/*
* Ordered list of offsets of objects in the pack.
*/
static void create_pack_revindex(struct pack_revindex *rix)
static void create_pack_revindex(struct packed_git *p)
{
struct packed_git *p = rix->p;
unsigned num_ent = p->num_objects;
unsigned i;
const char *index = p->index_data;
rix->revindex = xmalloc(sizeof(*rix->revindex) * (num_ent + 1));
p->revindex = xmalloc(sizeof(*p->revindex) * (num_ent + 1));
index += 4 * 256;
if (p->index_version > 1) {
@ -171,55 +131,42 @@ static void create_pack_revindex(struct pack_revindex *rix)
for (i = 0; i < num_ent; i++) {
uint32_t off = ntohl(*off_32++);
if (!(off & 0x80000000)) {
rix->revindex[i].offset = off;
p->revindex[i].offset = off;
} else {
rix->revindex[i].offset =
p->revindex[i].offset =
((uint64_t)ntohl(*off_64++)) << 32;
rix->revindex[i].offset |=
p->revindex[i].offset |=
ntohl(*off_64++);
}
rix->revindex[i].nr = i;
p->revindex[i].nr = i;
}
} else {
for (i = 0; i < num_ent; i++) {
uint32_t hl = *((uint32_t *)(index + 24 * i));
rix->revindex[i].offset = ntohl(hl);
rix->revindex[i].nr = i;
p->revindex[i].offset = ntohl(hl);
p->revindex[i].nr = i;
}
}
/* This knows the pack format -- the 20-byte trailer
* follows immediately after the last object data.
*/
rix->revindex[num_ent].offset = p->pack_size - 20;
rix->revindex[num_ent].nr = -1;
sort_revindex(rix->revindex, num_ent, p->pack_size);
p->revindex[num_ent].offset = p->pack_size - 20;
p->revindex[num_ent].nr = -1;
sort_revindex(p->revindex, num_ent, p->pack_size);
}
struct pack_revindex *revindex_for_pack(struct packed_git *p)
void load_pack_revindex(struct packed_git *p)
{
int num;
struct pack_revindex *rix;
if (!pack_revindex_hashsz)
init_pack_revindex();
num = pack_revindex_ix(p);
if (num < 0)
die("internal error: pack revindex fubar");
rix = &pack_revindex[num];
if (!rix->revindex)
create_pack_revindex(rix);
return rix;
if (!p->revindex)
create_pack_revindex(p);
}
int find_revindex_position(struct pack_revindex *pridx, off_t ofs)
int find_revindex_position(struct packed_git *p, off_t ofs)
{
int lo = 0;
int hi = pridx->p->num_objects + 1;
struct revindex_entry *revindex = pridx->revindex;
int hi = p->num_objects + 1;
struct revindex_entry *revindex = p->revindex;
do {
unsigned mi = lo + (hi - lo) / 2;
@ -237,11 +184,13 @@ int find_revindex_position(struct pack_revindex *pridx, off_t ofs)
struct revindex_entry *find_pack_revindex(struct packed_git *p, off_t ofs)
{
struct pack_revindex *pridx = revindex_for_pack(p);
int pos = find_revindex_position(pridx, ofs);
int pos;
load_pack_revindex(p);
pos = find_revindex_position(p, ofs);
if (pos < 0)
return NULL;
return pridx->revindex + pos;
return p->revindex + pos;
}

View file

@ -1,18 +1,15 @@
#ifndef PACK_REVINDEX_H
#define PACK_REVINDEX_H
struct packed_git;
struct revindex_entry {
off_t offset;
unsigned int nr;
};
struct pack_revindex {
struct packed_git *p;
struct revindex_entry *revindex;
};
struct pack_revindex *revindex_for_pack(struct packed_git *p);
int find_revindex_position(struct pack_revindex *pridx, off_t ofs);
void load_pack_revindex(struct packed_git *p);
int find_revindex_position(struct packed_git *p, off_t ofs);
struct revindex_entry *find_pack_revindex(struct packed_git *p, off_t ofs);