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-rw-r--r--pack-bitmap-write.c535
1 files changed, 535 insertions, 0 deletions
diff --git a/pack-bitmap-write.c b/pack-bitmap-write.c
new file mode 100644
index 0000000000..954a74d6cf
--- /dev/null
+++ b/pack-bitmap-write.c
@@ -0,0 +1,535 @@
+#include "cache.h"
+#include "commit.h"
+#include "tag.h"
+#include "diff.h"
+#include "revision.h"
+#include "list-objects.h"
+#include "progress.h"
+#include "pack-revindex.h"
+#include "pack.h"
+#include "pack-bitmap.h"
+#include "sha1-lookup.h"
+#include "pack-objects.h"
+
+struct bitmapped_commit {
+ struct commit *commit;
+ struct ewah_bitmap *bitmap;
+ struct ewah_bitmap *write_as;
+ int flags;
+ int xor_offset;
+ uint32_t commit_pos;
+};
+
+struct bitmap_writer {
+ struct ewah_bitmap *commits;
+ struct ewah_bitmap *trees;
+ struct ewah_bitmap *blobs;
+ struct ewah_bitmap *tags;
+
+ khash_sha1 *bitmaps;
+ khash_sha1 *reused;
+ struct packing_data *to_pack;
+
+ struct bitmapped_commit *selected;
+ unsigned int selected_nr, selected_alloc;
+
+ struct progress *progress;
+ int show_progress;
+ unsigned char pack_checksum[20];
+};
+
+static struct bitmap_writer writer;
+
+void bitmap_writer_show_progress(int show)
+{
+ writer.show_progress = show;
+}
+
+/**
+ * Build the initial type index for the packfile
+ */
+void bitmap_writer_build_type_index(struct pack_idx_entry **index,
+ uint32_t index_nr)
+{
+ uint32_t i;
+
+ writer.commits = ewah_new();
+ writer.trees = ewah_new();
+ writer.blobs = ewah_new();
+ writer.tags = ewah_new();
+
+ for (i = 0; i < index_nr; ++i) {
+ struct object_entry *entry = (struct object_entry *)index[i];
+ enum object_type real_type;
+
+ entry->in_pack_pos = i;
+
+ switch (entry->type) {
+ case OBJ_COMMIT:
+ case OBJ_TREE:
+ case OBJ_BLOB:
+ case OBJ_TAG:
+ real_type = entry->type;
+ break;
+
+ default:
+ real_type = sha1_object_info(entry->idx.sha1, NULL);
+ break;
+ }
+
+ switch (real_type) {
+ case OBJ_COMMIT:
+ ewah_set(writer.commits, i);
+ break;
+
+ case OBJ_TREE:
+ ewah_set(writer.trees, i);
+ break;
+
+ case OBJ_BLOB:
+ ewah_set(writer.blobs, i);
+ break;
+
+ case OBJ_TAG:
+ ewah_set(writer.tags, i);
+ break;
+
+ default:
+ die("Missing type information for %s (%d/%d)",
+ sha1_to_hex(entry->idx.sha1), real_type, entry->type);
+ }
+ }
+}
+
+/**
+ * Compute the actual bitmaps
+ */
+static struct object **seen_objects;
+static unsigned int seen_objects_nr, seen_objects_alloc;
+
+static inline void push_bitmapped_commit(struct commit *commit, struct ewah_bitmap *reused)
+{
+ if (writer.selected_nr >= writer.selected_alloc) {
+ writer.selected_alloc = (writer.selected_alloc + 32) * 2;
+ writer.selected = xrealloc(writer.selected,
+ writer.selected_alloc * sizeof(struct bitmapped_commit));
+ }
+
+ writer.selected[writer.selected_nr].commit = commit;
+ writer.selected[writer.selected_nr].bitmap = reused;
+ writer.selected[writer.selected_nr].flags = 0;
+
+ writer.selected_nr++;
+}
+
+static inline void mark_as_seen(struct object *object)
+{
+ ALLOC_GROW(seen_objects, seen_objects_nr + 1, seen_objects_alloc);
+ seen_objects[seen_objects_nr++] = object;
+}
+
+static inline void reset_all_seen(void)
+{
+ unsigned int i;
+ for (i = 0; i < seen_objects_nr; ++i) {
+ seen_objects[i]->flags &= ~(SEEN | ADDED | SHOWN);
+ }
+ seen_objects_nr = 0;
+}
+
+static uint32_t find_object_pos(const unsigned char *sha1)
+{
+ struct object_entry *entry = packlist_find(writer.to_pack, sha1, NULL);
+
+ if (!entry) {
+ die("Failed to write bitmap index. Packfile doesn't have full closure "
+ "(object %s is missing)", sha1_to_hex(sha1));
+ }
+
+ return entry->in_pack_pos;
+}
+
+static void show_object(struct object *object, const struct name_path *path,
+ const char *last, void *data)
+{
+ struct bitmap *base = data;
+ bitmap_set(base, find_object_pos(object->sha1));
+ mark_as_seen(object);
+}
+
+static void show_commit(struct commit *commit, void *data)
+{
+ mark_as_seen((struct object *)commit);
+}
+
+static int
+add_to_include_set(struct bitmap *base, struct commit *commit)
+{
+ khiter_t hash_pos;
+ uint32_t bitmap_pos = find_object_pos(commit->object.sha1);
+
+ if (bitmap_get(base, bitmap_pos))
+ return 0;
+
+ hash_pos = kh_get_sha1(writer.bitmaps, commit->object.sha1);
+ if (hash_pos < kh_end(writer.bitmaps)) {
+ struct bitmapped_commit *bc = kh_value(writer.bitmaps, hash_pos);
+ bitmap_or_ewah(base, bc->bitmap);
+ return 0;
+ }
+
+ bitmap_set(base, bitmap_pos);
+ return 1;
+}
+
+static int
+should_include(struct commit *commit, void *_data)
+{
+ struct bitmap *base = _data;
+
+ if (!add_to_include_set(base, commit)) {
+ struct commit_list *parent = commit->parents;
+
+ mark_as_seen((struct object *)commit);
+
+ while (parent) {
+ parent->item->object.flags |= SEEN;
+ mark_as_seen((struct object *)parent->item);
+ parent = parent->next;
+ }
+
+ return 0;
+ }
+
+ return 1;
+}
+
+static void compute_xor_offsets(void)
+{
+ static const int MAX_XOR_OFFSET_SEARCH = 10;
+
+ int i, next = 0;
+
+ while (next < writer.selected_nr) {
+ struct bitmapped_commit *stored = &writer.selected[next];
+
+ int best_offset = 0;
+ struct ewah_bitmap *best_bitmap = stored->bitmap;
+ struct ewah_bitmap *test_xor;
+
+ for (i = 1; i <= MAX_XOR_OFFSET_SEARCH; ++i) {
+ int curr = next - i;
+
+ if (curr < 0)
+ break;
+
+ test_xor = ewah_pool_new();
+ ewah_xor(writer.selected[curr].bitmap, stored->bitmap, test_xor);
+
+ if (test_xor->buffer_size < best_bitmap->buffer_size) {
+ if (best_bitmap != stored->bitmap)
+ ewah_pool_free(best_bitmap);
+
+ best_bitmap = test_xor;
+ best_offset = i;
+ } else {
+ ewah_pool_free(test_xor);
+ }
+ }
+
+ stored->xor_offset = best_offset;
+ stored->write_as = best_bitmap;
+
+ next++;
+ }
+}
+
+void bitmap_writer_build(struct packing_data *to_pack)
+{
+ static const double REUSE_BITMAP_THRESHOLD = 0.2;
+
+ int i, reuse_after, need_reset;
+ struct bitmap *base = bitmap_new();
+ struct rev_info revs;
+
+ writer.bitmaps = kh_init_sha1();
+ writer.to_pack = to_pack;
+
+ if (writer.show_progress)
+ writer.progress = start_progress("Building bitmaps", writer.selected_nr);
+
+ init_revisions(&revs, NULL);
+ revs.tag_objects = 1;
+ revs.tree_objects = 1;
+ revs.blob_objects = 1;
+ revs.no_walk = 0;
+
+ revs.include_check = should_include;
+ reset_revision_walk();
+
+ reuse_after = writer.selected_nr * REUSE_BITMAP_THRESHOLD;
+ need_reset = 0;
+
+ for (i = writer.selected_nr - 1; i >= 0; --i) {
+ struct bitmapped_commit *stored;
+ struct object *object;
+
+ khiter_t hash_pos;
+ int hash_ret;
+
+ stored = &writer.selected[i];
+ object = (struct object *)stored->commit;
+
+ if (stored->bitmap == NULL) {
+ if (i < writer.selected_nr - 1 &&
+ (need_reset ||
+ !in_merge_bases(writer.selected[i + 1].commit,
+ stored->commit))) {
+ bitmap_reset(base);
+ reset_all_seen();
+ }
+
+ add_pending_object(&revs, object, "");
+ revs.include_check_data = base;
+
+ if (prepare_revision_walk(&revs))
+ die("revision walk setup failed");
+
+ traverse_commit_list(&revs, show_commit, show_object, base);
+
+ revs.pending.nr = 0;
+ revs.pending.alloc = 0;
+ revs.pending.objects = NULL;
+
+ stored->bitmap = bitmap_to_ewah(base);
+ need_reset = 0;
+ } else
+ need_reset = 1;
+
+ if (i >= reuse_after)
+ stored->flags |= BITMAP_FLAG_REUSE;
+
+ hash_pos = kh_put_sha1(writer.bitmaps, object->sha1, &hash_ret);
+ if (hash_ret == 0)
+ die("Duplicate entry when writing index: %s",
+ sha1_to_hex(object->sha1));
+
+ kh_value(writer.bitmaps, hash_pos) = stored;
+ display_progress(writer.progress, writer.selected_nr - i);
+ }
+
+ bitmap_free(base);
+ stop_progress(&writer.progress);
+
+ compute_xor_offsets();
+}
+
+/**
+ * Select the commits that will be bitmapped
+ */
+static inline unsigned int next_commit_index(unsigned int idx)
+{
+ static const unsigned int MIN_COMMITS = 100;
+ static const unsigned int MAX_COMMITS = 5000;
+
+ static const unsigned int MUST_REGION = 100;
+ static const unsigned int MIN_REGION = 20000;
+
+ unsigned int offset, next;
+
+ if (idx <= MUST_REGION)
+ return 0;
+
+ if (idx <= MIN_REGION) {
+ offset = idx - MUST_REGION;
+ return (offset < MIN_COMMITS) ? offset : MIN_COMMITS;
+ }
+
+ offset = idx - MIN_REGION;
+ next = (offset < MAX_COMMITS) ? offset : MAX_COMMITS;
+
+ return (next > MIN_COMMITS) ? next : MIN_COMMITS;
+}
+
+static int date_compare(const void *_a, const void *_b)
+{
+ struct commit *a = *(struct commit **)_a;
+ struct commit *b = *(struct commit **)_b;
+ return (long)b->date - (long)a->date;
+}
+
+void bitmap_writer_reuse_bitmaps(struct packing_data *to_pack)
+{
+ if (prepare_bitmap_git() < 0)
+ return;
+
+ writer.reused = kh_init_sha1();
+ rebuild_existing_bitmaps(to_pack, writer.reused, writer.show_progress);
+}
+
+static struct ewah_bitmap *find_reused_bitmap(const unsigned char *sha1)
+{
+ khiter_t hash_pos;
+
+ if (!writer.reused)
+ return NULL;
+
+ hash_pos = kh_get_sha1(writer.reused, sha1);
+ if (hash_pos >= kh_end(writer.reused))
+ return NULL;
+
+ return kh_value(writer.reused, hash_pos);
+}
+
+void bitmap_writer_select_commits(struct commit **indexed_commits,
+ unsigned int indexed_commits_nr,
+ int max_bitmaps)
+{
+ unsigned int i = 0, j, next;
+
+ qsort(indexed_commits, indexed_commits_nr, sizeof(indexed_commits[0]),
+ date_compare);
+
+ if (writer.show_progress)
+ writer.progress = start_progress("Selecting bitmap commits", 0);
+
+ if (indexed_commits_nr < 100) {
+ for (i = 0; i < indexed_commits_nr; ++i)
+ push_bitmapped_commit(indexed_commits[i], NULL);
+ return;
+ }
+
+ for (;;) {
+ struct ewah_bitmap *reused_bitmap = NULL;
+ struct commit *chosen = NULL;
+
+ next = next_commit_index(i);
+
+ if (i + next >= indexed_commits_nr)
+ break;
+
+ if (max_bitmaps > 0 && writer.selected_nr >= max_bitmaps) {
+ writer.selected_nr = max_bitmaps;
+ break;
+ }
+
+ if (next == 0) {
+ chosen = indexed_commits[i];
+ reused_bitmap = find_reused_bitmap(chosen->object.sha1);
+ } else {
+ chosen = indexed_commits[i + next];
+
+ for (j = 0; j <= next; ++j) {
+ struct commit *cm = indexed_commits[i + j];
+
+ reused_bitmap = find_reused_bitmap(cm->object.sha1);
+ if (reused_bitmap || (cm->object.flags & NEEDS_BITMAP) != 0) {
+ chosen = cm;
+ break;
+ }
+
+ if (cm->parents && cm->parents->next)
+ chosen = cm;
+ }
+ }
+
+ push_bitmapped_commit(chosen, reused_bitmap);
+
+ i += next + 1;
+ display_progress(writer.progress, i);
+ }
+
+ stop_progress(&writer.progress);
+}
+
+
+static int sha1write_ewah_helper(void *f, const void *buf, size_t len)
+{
+ /* sha1write will die on error */
+ sha1write(f, buf, len);
+ return len;
+}
+
+/**
+ * Write the bitmap index to disk
+ */
+static inline void dump_bitmap(struct sha1file *f, struct ewah_bitmap *bitmap)
+{
+ if (ewah_serialize_to(bitmap, sha1write_ewah_helper, f) < 0)
+ die("Failed to write bitmap index");
+}
+
+static const unsigned char *sha1_access(size_t pos, void *table)
+{
+ struct pack_idx_entry **index = table;
+ return index[pos]->sha1;
+}
+
+static void write_selected_commits_v1(struct sha1file *f,
+ struct pack_idx_entry **index,
+ uint32_t index_nr)
+{
+ int i;
+
+ for (i = 0; i < writer.selected_nr; ++i) {
+ struct bitmapped_commit *stored = &writer.selected[i];
+ struct bitmap_disk_entry on_disk;
+
+ int commit_pos =
+ sha1_pos(stored->commit->object.sha1, index, index_nr, sha1_access);
+
+ if (commit_pos < 0)
+ die("BUG: trying to write commit not in index");
+
+ on_disk.object_pos = htonl(commit_pos);
+ on_disk.xor_offset = stored->xor_offset;
+ on_disk.flags = stored->flags;
+
+ sha1write(f, &on_disk, sizeof(on_disk));
+ dump_bitmap(f, stored->write_as);
+ }
+}
+
+void bitmap_writer_set_checksum(unsigned char *sha1)
+{
+ hashcpy(writer.pack_checksum, sha1);
+}
+
+void bitmap_writer_finish(struct pack_idx_entry **index,
+ uint32_t index_nr,
+ const char *filename)
+{
+ static char tmp_file[PATH_MAX];
+ static uint16_t default_version = 1;
+ static uint16_t flags = BITMAP_OPT_FULL_DAG;
+ struct sha1file *f;
+
+ struct bitmap_disk_header header;
+
+ int fd = odb_mkstemp(tmp_file, sizeof(tmp_file), "pack/tmp_bitmap_XXXXXX");
+
+ if (fd < 0)
+ die_errno("unable to create '%s'", tmp_file);
+ f = sha1fd(fd, tmp_file);
+
+ memcpy(header.magic, BITMAP_IDX_SIGNATURE, sizeof(BITMAP_IDX_SIGNATURE));
+ header.version = htons(default_version);
+ header.options = htons(flags);
+ header.entry_count = htonl(writer.selected_nr);
+ memcpy(header.checksum, writer.pack_checksum, 20);
+
+ sha1write(f, &header, sizeof(header));
+ dump_bitmap(f, writer.commits);
+ dump_bitmap(f, writer.trees);
+ dump_bitmap(f, writer.blobs);
+ dump_bitmap(f, writer.tags);
+ write_selected_commits_v1(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);
+}