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authorVicent Marti <tanoku@gmail.com>2013-10-24 18:01:06 (GMT)
committerJunio C Hamano <gitster@pobox.com>2013-10-24 22:44:48 (GMT)
commit2834bc27c16e4ae103768dd6dda530f0e46116af (patch)
tree5c26ff9d0bdf39c34dc7cb1c56d96d730167fb48
parent92e5c77c3791567e299cc858a7ddfed410e2cec5 (diff)
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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 <tanoku@gmail.com> Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
-rw-r--r--Makefile2
-rw-r--r--builtin/pack-objects.c175
-rw-r--r--pack-objects.c111
-rw-r--r--pack-objects.h47
4 files changed, 200 insertions, 135 deletions
diff --git a/Makefile b/Makefile
index af847f8..48ff0bd 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 36273dd..f3f0cf9 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;
@@ -90,21 +64,11 @@ 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 0000000..d01d851
--- /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 0000000..f528215
--- /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