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![Sun He](/assets/img/avatar_default.png)
We invented hashcpy() to keep the abstraction of "object name" behind it. Use it instead of calling memcpy() with hard-coded 20-byte length when moving object names between pieces of memory. Leave ppc/sha1.c as-is, because the function is about the SHA-1 hash algorithm whose output is and will always be 20 bytes. Helped-by: Michael Haggerty <mhagger@alum.mit.edu> Helped-by: Duy Nguyen <pclouds@gmail.com> Signed-off-by: Sun He <sunheehnus@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
553 lines
12 KiB
C
553 lines
12 KiB
C
#include "cache.h"
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#include "commit.h"
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#include "tag.h"
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#include "diff.h"
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#include "revision.h"
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#include "list-objects.h"
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#include "progress.h"
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#include "pack-revindex.h"
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#include "pack.h"
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#include "pack-bitmap.h"
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#include "sha1-lookup.h"
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#include "pack-objects.h"
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struct bitmapped_commit {
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struct commit *commit;
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struct ewah_bitmap *bitmap;
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struct ewah_bitmap *write_as;
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int flags;
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int xor_offset;
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uint32_t commit_pos;
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};
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struct bitmap_writer {
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struct ewah_bitmap *commits;
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struct ewah_bitmap *trees;
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struct ewah_bitmap *blobs;
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struct ewah_bitmap *tags;
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khash_sha1 *bitmaps;
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khash_sha1 *reused;
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struct packing_data *to_pack;
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struct bitmapped_commit *selected;
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unsigned int selected_nr, selected_alloc;
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struct progress *progress;
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int show_progress;
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unsigned char pack_checksum[20];
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};
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static struct bitmap_writer writer;
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void bitmap_writer_show_progress(int show)
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{
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writer.show_progress = show;
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}
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/**
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* Build the initial type index for the packfile
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*/
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void bitmap_writer_build_type_index(struct pack_idx_entry **index,
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uint32_t index_nr)
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{
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uint32_t i;
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writer.commits = ewah_new();
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writer.trees = ewah_new();
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writer.blobs = ewah_new();
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writer.tags = ewah_new();
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for (i = 0; i < index_nr; ++i) {
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struct object_entry *entry = (struct object_entry *)index[i];
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enum object_type real_type;
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entry->in_pack_pos = i;
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switch (entry->type) {
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case OBJ_COMMIT:
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case OBJ_TREE:
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case OBJ_BLOB:
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case OBJ_TAG:
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real_type = entry->type;
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break;
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default:
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real_type = sha1_object_info(entry->idx.sha1, NULL);
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break;
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}
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switch (real_type) {
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case OBJ_COMMIT:
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ewah_set(writer.commits, i);
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break;
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case OBJ_TREE:
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ewah_set(writer.trees, i);
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break;
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case OBJ_BLOB:
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ewah_set(writer.blobs, i);
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break;
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case OBJ_TAG:
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ewah_set(writer.tags, i);
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break;
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default:
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die("Missing type information for %s (%d/%d)",
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sha1_to_hex(entry->idx.sha1), real_type, entry->type);
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}
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}
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}
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/**
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* Compute the actual bitmaps
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*/
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static struct object **seen_objects;
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static unsigned int seen_objects_nr, seen_objects_alloc;
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static inline void push_bitmapped_commit(struct commit *commit, struct ewah_bitmap *reused)
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{
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if (writer.selected_nr >= writer.selected_alloc) {
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writer.selected_alloc = (writer.selected_alloc + 32) * 2;
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writer.selected = xrealloc(writer.selected,
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writer.selected_alloc * sizeof(struct bitmapped_commit));
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}
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writer.selected[writer.selected_nr].commit = commit;
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writer.selected[writer.selected_nr].bitmap = reused;
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writer.selected[writer.selected_nr].flags = 0;
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writer.selected_nr++;
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}
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static inline void mark_as_seen(struct object *object)
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{
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ALLOC_GROW(seen_objects, seen_objects_nr + 1, seen_objects_alloc);
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seen_objects[seen_objects_nr++] = object;
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}
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static inline void reset_all_seen(void)
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{
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unsigned int i;
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for (i = 0; i < seen_objects_nr; ++i) {
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seen_objects[i]->flags &= ~(SEEN | ADDED | SHOWN);
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}
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seen_objects_nr = 0;
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}
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static uint32_t find_object_pos(const unsigned char *sha1)
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{
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struct object_entry *entry = packlist_find(writer.to_pack, sha1, NULL);
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if (!entry) {
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die("Failed to write bitmap index. Packfile doesn't have full closure "
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"(object %s is missing)", sha1_to_hex(sha1));
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}
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return entry->in_pack_pos;
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}
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static void show_object(struct object *object, const struct name_path *path,
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const char *last, void *data)
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{
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struct bitmap *base = data;
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bitmap_set(base, find_object_pos(object->sha1));
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mark_as_seen(object);
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}
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static void show_commit(struct commit *commit, void *data)
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{
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mark_as_seen((struct object *)commit);
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}
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static int
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add_to_include_set(struct bitmap *base, struct commit *commit)
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{
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khiter_t hash_pos;
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uint32_t bitmap_pos = find_object_pos(commit->object.sha1);
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if (bitmap_get(base, bitmap_pos))
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return 0;
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hash_pos = kh_get_sha1(writer.bitmaps, commit->object.sha1);
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if (hash_pos < kh_end(writer.bitmaps)) {
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struct bitmapped_commit *bc = kh_value(writer.bitmaps, hash_pos);
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bitmap_or_ewah(base, bc->bitmap);
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return 0;
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}
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bitmap_set(base, bitmap_pos);
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return 1;
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}
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static int
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should_include(struct commit *commit, void *_data)
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{
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struct bitmap *base = _data;
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if (!add_to_include_set(base, commit)) {
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struct commit_list *parent = commit->parents;
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mark_as_seen((struct object *)commit);
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while (parent) {
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parent->item->object.flags |= SEEN;
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mark_as_seen((struct object *)parent->item);
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parent = parent->next;
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}
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return 0;
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}
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return 1;
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}
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static void compute_xor_offsets(void)
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{
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static const int MAX_XOR_OFFSET_SEARCH = 10;
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int i, next = 0;
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while (next < writer.selected_nr) {
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struct bitmapped_commit *stored = &writer.selected[next];
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int best_offset = 0;
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struct ewah_bitmap *best_bitmap = stored->bitmap;
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struct ewah_bitmap *test_xor;
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for (i = 1; i <= MAX_XOR_OFFSET_SEARCH; ++i) {
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int curr = next - i;
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if (curr < 0)
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break;
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test_xor = ewah_pool_new();
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ewah_xor(writer.selected[curr].bitmap, stored->bitmap, test_xor);
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if (test_xor->buffer_size < best_bitmap->buffer_size) {
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if (best_bitmap != stored->bitmap)
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ewah_pool_free(best_bitmap);
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best_bitmap = test_xor;
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best_offset = i;
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} else {
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ewah_pool_free(test_xor);
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}
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}
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stored->xor_offset = best_offset;
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stored->write_as = best_bitmap;
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next++;
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}
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}
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void bitmap_writer_build(struct packing_data *to_pack)
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{
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static const double REUSE_BITMAP_THRESHOLD = 0.2;
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int i, reuse_after, need_reset;
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struct bitmap *base = bitmap_new();
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struct rev_info revs;
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writer.bitmaps = kh_init_sha1();
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writer.to_pack = to_pack;
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if (writer.show_progress)
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writer.progress = start_progress("Building bitmaps", writer.selected_nr);
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init_revisions(&revs, NULL);
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revs.tag_objects = 1;
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revs.tree_objects = 1;
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revs.blob_objects = 1;
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revs.no_walk = 0;
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revs.include_check = should_include;
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reset_revision_walk();
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reuse_after = writer.selected_nr * REUSE_BITMAP_THRESHOLD;
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need_reset = 0;
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for (i = writer.selected_nr - 1; i >= 0; --i) {
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struct bitmapped_commit *stored;
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struct object *object;
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khiter_t hash_pos;
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int hash_ret;
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stored = &writer.selected[i];
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object = (struct object *)stored->commit;
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if (stored->bitmap == NULL) {
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if (i < writer.selected_nr - 1 &&
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(need_reset ||
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!in_merge_bases(writer.selected[i + 1].commit,
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stored->commit))) {
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bitmap_reset(base);
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reset_all_seen();
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}
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add_pending_object(&revs, object, "");
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revs.include_check_data = base;
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if (prepare_revision_walk(&revs))
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die("revision walk setup failed");
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traverse_commit_list(&revs, show_commit, show_object, base);
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revs.pending.nr = 0;
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revs.pending.alloc = 0;
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revs.pending.objects = NULL;
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stored->bitmap = bitmap_to_ewah(base);
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need_reset = 0;
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} else
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need_reset = 1;
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if (i >= reuse_after)
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stored->flags |= BITMAP_FLAG_REUSE;
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hash_pos = kh_put_sha1(writer.bitmaps, object->sha1, &hash_ret);
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if (hash_ret == 0)
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die("Duplicate entry when writing index: %s",
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sha1_to_hex(object->sha1));
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kh_value(writer.bitmaps, hash_pos) = stored;
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display_progress(writer.progress, writer.selected_nr - i);
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}
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bitmap_free(base);
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stop_progress(&writer.progress);
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compute_xor_offsets();
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}
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/**
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* Select the commits that will be bitmapped
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*/
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static inline unsigned int next_commit_index(unsigned int idx)
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{
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static const unsigned int MIN_COMMITS = 100;
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static const unsigned int MAX_COMMITS = 5000;
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static const unsigned int MUST_REGION = 100;
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static const unsigned int MIN_REGION = 20000;
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unsigned int offset, next;
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if (idx <= MUST_REGION)
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return 0;
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if (idx <= MIN_REGION) {
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offset = idx - MUST_REGION;
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return (offset < MIN_COMMITS) ? offset : MIN_COMMITS;
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}
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offset = idx - MIN_REGION;
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next = (offset < MAX_COMMITS) ? offset : MAX_COMMITS;
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return (next > MIN_COMMITS) ? next : MIN_COMMITS;
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}
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static int date_compare(const void *_a, const void *_b)
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{
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struct commit *a = *(struct commit **)_a;
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struct commit *b = *(struct commit **)_b;
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return (long)b->date - (long)a->date;
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}
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void bitmap_writer_reuse_bitmaps(struct packing_data *to_pack)
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{
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if (prepare_bitmap_git() < 0)
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return;
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writer.reused = kh_init_sha1();
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rebuild_existing_bitmaps(to_pack, writer.reused, writer.show_progress);
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}
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static struct ewah_bitmap *find_reused_bitmap(const unsigned char *sha1)
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{
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khiter_t hash_pos;
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if (!writer.reused)
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return NULL;
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hash_pos = kh_get_sha1(writer.reused, sha1);
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if (hash_pos >= kh_end(writer.reused))
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return NULL;
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return kh_value(writer.reused, hash_pos);
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}
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void bitmap_writer_select_commits(struct commit **indexed_commits,
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unsigned int indexed_commits_nr,
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int max_bitmaps)
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{
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unsigned int i = 0, j, next;
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qsort(indexed_commits, indexed_commits_nr, sizeof(indexed_commits[0]),
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date_compare);
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if (writer.show_progress)
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writer.progress = start_progress("Selecting bitmap commits", 0);
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if (indexed_commits_nr < 100) {
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for (i = 0; i < indexed_commits_nr; ++i)
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push_bitmapped_commit(indexed_commits[i], NULL);
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return;
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}
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for (;;) {
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struct ewah_bitmap *reused_bitmap = NULL;
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struct commit *chosen = NULL;
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next = next_commit_index(i);
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if (i + next >= indexed_commits_nr)
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break;
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if (max_bitmaps > 0 && writer.selected_nr >= max_bitmaps) {
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writer.selected_nr = max_bitmaps;
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break;
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}
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if (next == 0) {
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chosen = indexed_commits[i];
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reused_bitmap = find_reused_bitmap(chosen->object.sha1);
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} else {
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chosen = indexed_commits[i + next];
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for (j = 0; j <= next; ++j) {
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struct commit *cm = indexed_commits[i + j];
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reused_bitmap = find_reused_bitmap(cm->object.sha1);
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if (reused_bitmap || (cm->object.flags & NEEDS_BITMAP) != 0) {
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chosen = cm;
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break;
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}
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if (cm->parents && cm->parents->next)
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chosen = cm;
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}
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}
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push_bitmapped_commit(chosen, reused_bitmap);
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i += next + 1;
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display_progress(writer.progress, i);
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}
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stop_progress(&writer.progress);
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}
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static int sha1write_ewah_helper(void *f, const void *buf, size_t len)
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{
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/* sha1write will die on error */
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sha1write(f, buf, len);
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return len;
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}
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/**
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* Write the bitmap index to disk
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*/
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static inline void dump_bitmap(struct sha1file *f, struct ewah_bitmap *bitmap)
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{
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if (ewah_serialize_to(bitmap, sha1write_ewah_helper, f) < 0)
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die("Failed to write bitmap index");
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}
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static const unsigned char *sha1_access(size_t pos, void *table)
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{
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struct pack_idx_entry **index = table;
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return index[pos]->sha1;
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}
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static void write_selected_commits_v1(struct sha1file *f,
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struct pack_idx_entry **index,
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uint32_t index_nr)
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{
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int i;
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for (i = 0; i < writer.selected_nr; ++i) {
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struct bitmapped_commit *stored = &writer.selected[i];
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struct bitmap_disk_entry on_disk;
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int commit_pos =
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sha1_pos(stored->commit->object.sha1, index, index_nr, sha1_access);
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if (commit_pos < 0)
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die("BUG: trying to write commit not in index");
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on_disk.object_pos = htonl(commit_pos);
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on_disk.xor_offset = stored->xor_offset;
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on_disk.flags = stored->flags;
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sha1write(f, &on_disk, sizeof(on_disk));
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dump_bitmap(f, stored->write_as);
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}
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}
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static void write_hash_cache(struct sha1file *f,
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struct pack_idx_entry **index,
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uint32_t index_nr)
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{
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uint32_t i;
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for (i = 0; i < index_nr; ++i) {
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struct object_entry *entry = (struct object_entry *)index[i];
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uint32_t hash_value = htonl(entry->hash);
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sha1write(f, &hash_value, sizeof(hash_value));
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}
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}
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void bitmap_writer_set_checksum(unsigned char *sha1)
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{
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hashcpy(writer.pack_checksum, sha1);
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}
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void bitmap_writer_finish(struct pack_idx_entry **index,
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uint32_t index_nr,
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const char *filename,
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uint16_t options)
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{
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static char tmp_file[PATH_MAX];
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static uint16_t default_version = 1;
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static uint16_t flags = BITMAP_OPT_FULL_DAG;
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struct sha1file *f;
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struct bitmap_disk_header header;
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int fd = odb_mkstemp(tmp_file, sizeof(tmp_file), "pack/tmp_bitmap_XXXXXX");
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if (fd < 0)
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die_errno("unable to create '%s'", tmp_file);
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f = sha1fd(fd, tmp_file);
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memcpy(header.magic, BITMAP_IDX_SIGNATURE, sizeof(BITMAP_IDX_SIGNATURE));
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header.version = htons(default_version);
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header.options = htons(flags | options);
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header.entry_count = htonl(writer.selected_nr);
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hashcpy(header.checksum, writer.pack_checksum);
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sha1write(f, &header, sizeof(header));
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dump_bitmap(f, writer.commits);
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dump_bitmap(f, writer.trees);
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dump_bitmap(f, writer.blobs);
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dump_bitmap(f, writer.tags);
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write_selected_commits_v1(f, index, index_nr);
|
|
|
|
if (options & BITMAP_OPT_HASH_CACHE)
|
|
write_hash_cache(f, index, index_nr);
|
|
|
|
sha1close(f, NULL, CSUM_FSYNC);
|
|
|
|
if (adjust_shared_perm(tmp_file))
|
|
die_errno("unable to make temporary bitmap file readable");
|
|
|
|
if (rename(tmp_file, filename))
|
|
die_errno("unable to rename temporary bitmap file to '%s'", filename);
|
|
}
|