diff options
Diffstat (limited to 'blame.c')
| -rw-r--r-- | blame.c | 1903 |
1 files changed, 1903 insertions, 0 deletions
diff --git a/blame.c b/blame.c new file mode 100644 index 0000000000..43861437f7 --- /dev/null +++ b/blame.c @@ -0,0 +1,1903 @@ +#include "cache.h" +#include "refs.h" +#include "object-store.h" +#include "cache-tree.h" +#include "mergesort.h" +#include "diff.h" +#include "diffcore.h" +#include "tag.h" +#include "blame.h" +#include "alloc.h" +#include "commit-slab.h" + +define_commit_slab(blame_suspects, struct blame_origin *); +static struct blame_suspects blame_suspects; + +struct blame_origin *get_blame_suspects(struct commit *commit) +{ + struct blame_origin **result; + + result = blame_suspects_peek(&blame_suspects, commit); + + return result ? *result : NULL; +} + +static void set_blame_suspects(struct commit *commit, struct blame_origin *origin) +{ + *blame_suspects_at(&blame_suspects, commit) = origin; +} + +void blame_origin_decref(struct blame_origin *o) +{ + if (o && --o->refcnt <= 0) { + struct blame_origin *p, *l = NULL; + if (o->previous) + blame_origin_decref(o->previous); + free(o->file.ptr); + /* Should be present exactly once in commit chain */ + for (p = get_blame_suspects(o->commit); p; l = p, p = p->next) { + if (p == o) { + if (l) + l->next = p->next; + else + set_blame_suspects(o->commit, p->next); + free(o); + return; + } + } + die("internal error in blame_origin_decref"); + } +} + +/* + * Given a commit and a path in it, create a new origin structure. + * The callers that add blame to the scoreboard should use + * get_origin() to obtain shared, refcounted copy instead of calling + * this function directly. + */ +static struct blame_origin *make_origin(struct commit *commit, const char *path) +{ + struct blame_origin *o; + FLEX_ALLOC_STR(o, path, path); + o->commit = commit; + o->refcnt = 1; + o->next = get_blame_suspects(commit); + set_blame_suspects(commit, o); + return o; +} + +/* + * Locate an existing origin or create a new one. + * This moves the origin to front position in the commit util list. + */ +static struct blame_origin *get_origin(struct commit *commit, const char *path) +{ + struct blame_origin *o, *l; + + for (o = get_blame_suspects(commit), l = NULL; o; l = o, o = o->next) { + if (!strcmp(o->path, path)) { + /* bump to front */ + if (l) { + l->next = o->next; + o->next = get_blame_suspects(commit); + set_blame_suspects(commit, o); + } + return blame_origin_incref(o); + } + } + return make_origin(commit, path); +} + + + +static void verify_working_tree_path(struct repository *r, + struct commit *work_tree, const char *path) +{ + struct commit_list *parents; + int pos; + + for (parents = work_tree->parents; parents; parents = parents->next) { + const struct object_id *commit_oid = &parents->item->object.oid; + struct object_id blob_oid; + unsigned mode; + + if (!get_tree_entry(commit_oid, path, &blob_oid, &mode) && + oid_object_info(r, &blob_oid, NULL) == OBJ_BLOB) + return; + } + + pos = index_name_pos(r->index, path, strlen(path)); + if (pos >= 0) + ; /* path is in the index */ + else if (-1 - pos < r->index->cache_nr && + !strcmp(r->index->cache[-1 - pos]->name, path)) + ; /* path is in the index, unmerged */ + else + die("no such path '%s' in HEAD", path); +} + +static struct commit_list **append_parent(struct repository *r, + struct commit_list **tail, + const struct object_id *oid) +{ + struct commit *parent; + + parent = lookup_commit_reference(r, oid); + if (!parent) + die("no such commit %s", oid_to_hex(oid)); + return &commit_list_insert(parent, tail)->next; +} + +static void append_merge_parents(struct repository *r, + struct commit_list **tail) +{ + int merge_head; + struct strbuf line = STRBUF_INIT; + + merge_head = open(git_path_merge_head(r), O_RDONLY); + if (merge_head < 0) { + if (errno == ENOENT) + return; + die("cannot open '%s' for reading", + git_path_merge_head(r)); + } + + while (!strbuf_getwholeline_fd(&line, merge_head, '\n')) { + struct object_id oid; + if (line.len < GIT_SHA1_HEXSZ || get_oid_hex(line.buf, &oid)) + die("unknown line in '%s': %s", + git_path_merge_head(r), line.buf); + tail = append_parent(r, tail, &oid); + } + close(merge_head); + strbuf_release(&line); +} + +/* + * This isn't as simple as passing sb->buf and sb->len, because we + * want to transfer ownership of the buffer to the commit (so we + * must use detach). + */ +static void set_commit_buffer_from_strbuf(struct repository *r, + struct commit *c, + struct strbuf *sb) +{ + size_t len; + void *buf = strbuf_detach(sb, &len); + set_commit_buffer(r, c, buf, len); +} + +/* + * Prepare a dummy commit that represents the work tree (or staged) item. + * Note that annotating work tree item never works in the reverse. + */ +static struct commit *fake_working_tree_commit(struct repository *r, + struct diff_options *opt, + const char *path, + const char *contents_from) +{ + struct commit *commit; + struct blame_origin *origin; + struct commit_list **parent_tail, *parent; + struct object_id head_oid; + struct strbuf buf = STRBUF_INIT; + const char *ident; + time_t now; + int len; + struct cache_entry *ce; + unsigned mode; + struct strbuf msg = STRBUF_INIT; + + read_index(r->index); + time(&now); + commit = alloc_commit_node(r); + commit->object.parsed = 1; + commit->date = now; + parent_tail = &commit->parents; + + if (!resolve_ref_unsafe("HEAD", RESOLVE_REF_READING, &head_oid, NULL)) + die("no such ref: HEAD"); + + parent_tail = append_parent(r, parent_tail, &head_oid); + append_merge_parents(r, parent_tail); + verify_working_tree_path(r, commit, path); + + origin = make_origin(commit, path); + + ident = fmt_ident("Not Committed Yet", "not.committed.yet", NULL, 0); + strbuf_addstr(&msg, "tree 0000000000000000000000000000000000000000\n"); + for (parent = commit->parents; parent; parent = parent->next) + strbuf_addf(&msg, "parent %s\n", + oid_to_hex(&parent->item->object.oid)); + strbuf_addf(&msg, + "author %s\n" + "committer %s\n\n" + "Version of %s from %s\n", + ident, ident, path, + (!contents_from ? path : + (!strcmp(contents_from, "-") ? "standard input" : contents_from))); + set_commit_buffer_from_strbuf(r, commit, &msg); + + if (!contents_from || strcmp("-", contents_from)) { + struct stat st; + const char *read_from; + char *buf_ptr; + unsigned long buf_len; + + if (contents_from) { + if (stat(contents_from, &st) < 0) + die_errno("Cannot stat '%s'", contents_from); + read_from = contents_from; + } + else { + if (lstat(path, &st) < 0) + die_errno("Cannot lstat '%s'", path); + read_from = path; + } + mode = canon_mode(st.st_mode); + + switch (st.st_mode & S_IFMT) { + case S_IFREG: + if (opt->flags.allow_textconv && + textconv_object(r, read_from, mode, &null_oid, 0, &buf_ptr, &buf_len)) + strbuf_attach(&buf, buf_ptr, buf_len, buf_len + 1); + else if (strbuf_read_file(&buf, read_from, st.st_size) != st.st_size) + die_errno("cannot open or read '%s'", read_from); + break; + case S_IFLNK: + if (strbuf_readlink(&buf, read_from, st.st_size) < 0) + die_errno("cannot readlink '%s'", read_from); + break; + default: + die("unsupported file type %s", read_from); + } + } + else { + /* Reading from stdin */ + mode = 0; + if (strbuf_read(&buf, 0, 0) < 0) + die_errno("failed to read from stdin"); + } + convert_to_git(r->index, path, buf.buf, buf.len, &buf, 0); + origin->file.ptr = buf.buf; + origin->file.size = buf.len; + pretend_object_file(buf.buf, buf.len, OBJ_BLOB, &origin->blob_oid); + + /* + * Read the current index, replace the path entry with + * origin->blob_sha1 without mucking with its mode or type + * bits; we are not going to write this index out -- we just + * want to run "diff-index --cached". + */ + discard_index(r->index); + read_index(r->index); + + len = strlen(path); + if (!mode) { + int pos = index_name_pos(r->index, path, len); + if (0 <= pos) + mode = r->index->cache[pos]->ce_mode; + else + /* Let's not bother reading from HEAD tree */ + mode = S_IFREG | 0644; + } + ce = make_empty_cache_entry(r->index, len); + oidcpy(&ce->oid, &origin->blob_oid); + memcpy(ce->name, path, len); + ce->ce_flags = create_ce_flags(0); + ce->ce_namelen = len; + ce->ce_mode = create_ce_mode(mode); + add_index_entry(r->index, ce, + ADD_CACHE_OK_TO_ADD | ADD_CACHE_OK_TO_REPLACE); + + cache_tree_invalidate_path(r->index, path); + + return commit; +} + + + +static int diff_hunks(mmfile_t *file_a, mmfile_t *file_b, + xdl_emit_hunk_consume_func_t hunk_func, void *cb_data, int xdl_opts) +{ + xpparam_t xpp = {0}; + xdemitconf_t xecfg = {0}; + xdemitcb_t ecb = {NULL}; + + xpp.flags = xdl_opts; + xecfg.hunk_func = hunk_func; + ecb.priv = cb_data; + return xdi_diff(file_a, file_b, &xpp, &xecfg, &ecb); +} + +/* + * Given an origin, prepare mmfile_t structure to be used by the + * diff machinery + */ +static void fill_origin_blob(struct diff_options *opt, + struct blame_origin *o, mmfile_t *file, int *num_read_blob) +{ + if (!o->file.ptr) { + enum object_type type; + unsigned long file_size; + + (*num_read_blob)++; + if (opt->flags.allow_textconv && + textconv_object(opt->repo, o->path, o->mode, + &o->blob_oid, 1, &file->ptr, &file_size)) + ; + else + file->ptr = read_object_file(&o->blob_oid, &type, + &file_size); + file->size = file_size; + + if (!file->ptr) + die("Cannot read blob %s for path %s", + oid_to_hex(&o->blob_oid), + o->path); + o->file = *file; + } + else + *file = o->file; +} + +static void drop_origin_blob(struct blame_origin *o) +{ + FREE_AND_NULL(o->file.ptr); +} + +/* + * Any merge of blames happens on lists of blames that arrived via + * different parents in a single suspect. In this case, we want to + * sort according to the suspect line numbers as opposed to the final + * image line numbers. The function body is somewhat longish because + * it avoids unnecessary writes. + */ + +static struct blame_entry *blame_merge(struct blame_entry *list1, + struct blame_entry *list2) +{ + struct blame_entry *p1 = list1, *p2 = list2, + **tail = &list1; + + if (!p1) + return p2; + if (!p2) + return p1; + + if (p1->s_lno <= p2->s_lno) { + do { + tail = &p1->next; + if ((p1 = *tail) == NULL) { + *tail = p2; + return list1; + } + } while (p1->s_lno <= p2->s_lno); + } + for (;;) { + *tail = p2; + do { + tail = &p2->next; + if ((p2 = *tail) == NULL) { + *tail = p1; + return list1; + } + } while (p1->s_lno > p2->s_lno); + *tail = p1; + do { + tail = &p1->next; + if ((p1 = *tail) == NULL) { + *tail = p2; + return list1; + } + } while (p1->s_lno <= p2->s_lno); + } +} + +static void *get_next_blame(const void *p) +{ + return ((struct blame_entry *)p)->next; +} + +static void set_next_blame(void *p1, void *p2) +{ + ((struct blame_entry *)p1)->next = p2; +} + +/* + * Final image line numbers are all different, so we don't need a + * three-way comparison here. + */ + +static int compare_blame_final(const void *p1, const void *p2) +{ + return ((struct blame_entry *)p1)->lno > ((struct blame_entry *)p2)->lno + ? 1 : -1; +} + +static int compare_blame_suspect(const void *p1, const void *p2) +{ + const struct blame_entry *s1 = p1, *s2 = p2; + /* + * to allow for collating suspects, we sort according to the + * respective pointer value as the primary sorting criterion. + * The actual relation is pretty unimportant as long as it + * establishes a total order. Comparing as integers gives us + * that. + */ + if (s1->suspect != s2->suspect) + return (intptr_t)s1->suspect > (intptr_t)s2->suspect ? 1 : -1; + if (s1->s_lno == s2->s_lno) + return 0; + return s1->s_lno > s2->s_lno ? 1 : -1; +} + +void blame_sort_final(struct blame_scoreboard *sb) +{ + sb->ent = llist_mergesort(sb->ent, get_next_blame, set_next_blame, + compare_blame_final); +} + +static int compare_commits_by_reverse_commit_date(const void *a, + const void *b, + void *c) +{ + return -compare_commits_by_commit_date(a, b, c); +} + +/* + * For debugging -- origin is refcounted, and this asserts that + * we do not underflow. + */ +static void sanity_check_refcnt(struct blame_scoreboard *sb) +{ + int baa = 0; + struct blame_entry *ent; + + for (ent = sb->ent; ent; ent = ent->next) { + /* Nobody should have zero or negative refcnt */ + if (ent->suspect->refcnt <= 0) { + fprintf(stderr, "%s in %s has negative refcnt %d\n", + ent->suspect->path, + oid_to_hex(&ent->suspect->commit->object.oid), + ent->suspect->refcnt); + baa = 1; + } + } + if (baa) + sb->on_sanity_fail(sb, baa); +} + +/* + * If two blame entries that are next to each other came from + * contiguous lines in the same origin (i.e. <commit, path> pair), + * merge them together. + */ +void blame_coalesce(struct blame_scoreboard *sb) +{ + struct blame_entry *ent, *next; + + for (ent = sb->ent; ent && (next = ent->next); ent = next) { + if (ent->suspect == next->suspect && + ent->s_lno + ent->num_lines == next->s_lno) { + ent->num_lines += next->num_lines; + ent->next = next->next; + blame_origin_decref(next->suspect); + free(next); + ent->score = 0; + next = ent; /* again */ + } + } + + if (sb->debug) /* sanity */ + sanity_check_refcnt(sb); +} + +/* + * Merge the given sorted list of blames into a preexisting origin. + * If there were no previous blames to that commit, it is entered into + * the commit priority queue of the score board. + */ + +static void queue_blames(struct blame_scoreboard *sb, struct blame_origin *porigin, + struct blame_entry *sorted) +{ + if (porigin->suspects) + porigin->suspects = blame_merge(porigin->suspects, sorted); + else { + struct blame_origin *o; + for (o = get_blame_suspects(porigin->commit); o; o = o->next) { + if (o->suspects) { + porigin->suspects = sorted; + return; + } + } + porigin->suspects = sorted; + prio_queue_put(&sb->commits, porigin->commit); + } +} + +/* + * Fill the blob_sha1 field of an origin if it hasn't, so that later + * call to fill_origin_blob() can use it to locate the data. blob_sha1 + * for an origin is also used to pass the blame for the entire file to + * the parent to detect the case where a child's blob is identical to + * that of its parent's. + * + * This also fills origin->mode for corresponding tree path. + */ +static int fill_blob_sha1_and_mode(struct repository *r, + struct blame_origin *origin) +{ + if (!is_null_oid(&origin->blob_oid)) + return 0; + if (get_tree_entry(&origin->commit->object.oid, origin->path, &origin->blob_oid, &origin->mode)) + goto error_out; + if (oid_object_info(r, &origin->blob_oid, NULL) != OBJ_BLOB) + goto error_out; + return 0; + error_out: + oidclr(&origin->blob_oid); + origin->mode = S_IFINVALID; + return -1; +} + +/* + * We have an origin -- check if the same path exists in the + * parent and return an origin structure to represent it. + */ +static struct blame_origin *find_origin(struct repository *r, + struct commit *parent, + struct blame_origin *origin) +{ + struct blame_origin *porigin; + struct diff_options diff_opts; + const char *paths[2]; + + /* First check any existing origins */ + for (porigin = get_blame_suspects(parent); porigin; porigin = porigin->next) + if (!strcmp(porigin->path, origin->path)) { + /* + * The same path between origin and its parent + * without renaming -- the most common case. + */ + return blame_origin_incref (porigin); + } + + /* See if the origin->path is different between parent + * and origin first. Most of the time they are the + * same and diff-tree is fairly efficient about this. + */ + repo_diff_setup(r, &diff_opts); + diff_opts.flags.recursive = 1; + diff_opts.detect_rename = 0; + diff_opts.output_format = DIFF_FORMAT_NO_OUTPUT; + paths[0] = origin->path; + paths[1] = NULL; + + parse_pathspec(&diff_opts.pathspec, + PATHSPEC_ALL_MAGIC & ~PATHSPEC_LITERAL, + PATHSPEC_LITERAL_PATH, "", paths); + diff_setup_done(&diff_opts); + + if (is_null_oid(&origin->commit->object.oid)) + do_diff_cache(get_commit_tree_oid(parent), &diff_opts); + else + diff_tree_oid(get_commit_tree_oid(parent), + get_commit_tree_oid(origin->commit), + "", &diff_opts); + diffcore_std(&diff_opts); + + if (!diff_queued_diff.nr) { + /* The path is the same as parent */ + porigin = get_origin(parent, origin->path); + oidcpy(&porigin->blob_oid, &origin->blob_oid); + porigin->mode = origin->mode; + } else { + /* + * Since origin->path is a pathspec, if the parent + * commit had it as a directory, we will see a whole + * bunch of deletion of files in the directory that we + * do not care about. + */ + int i; + struct diff_filepair *p = NULL; + for (i = 0; i < diff_queued_diff.nr; i++) { + const char *name; + p = diff_queued_diff.queue[i]; + name = p->one->path ? p->one->path : p->two->path; + if (!strcmp(name, origin->path)) + break; + } + if (!p) + die("internal error in blame::find_origin"); + switch (p->status) { + default: + die("internal error in blame::find_origin (%c)", + p->status); + case 'M': + porigin = get_origin(parent, origin->path); + oidcpy(&porigin->blob_oid, &p->one->oid); + porigin->mode = p->one->mode; + break; + case 'A': + case 'T': + /* Did not exist in parent, or type changed */ + break; + } + } + diff_flush(&diff_opts); + clear_pathspec(&diff_opts.pathspec); + return porigin; +} + +/* + * We have an origin -- find the path that corresponds to it in its + * parent and return an origin structure to represent it. + */ +static struct blame_origin *find_rename(struct repository *r, + struct commit *parent, + struct blame_origin *origin) +{ + struct blame_origin *porigin = NULL; + struct diff_options diff_opts; + int i; + + repo_diff_setup(r, &diff_opts); + diff_opts.flags.recursive = 1; + diff_opts.detect_rename = DIFF_DETECT_RENAME; + diff_opts.output_format = DIFF_FORMAT_NO_OUTPUT; + diff_opts.single_follow = origin->path; + diff_setup_done(&diff_opts); + + if (is_null_oid(&origin->commit->object.oid)) + do_diff_cache(get_commit_tree_oid(parent), &diff_opts); + else + diff_tree_oid(get_commit_tree_oid(parent), + get_commit_tree_oid(origin->commit), + "", &diff_opts); + diffcore_std(&diff_opts); + + for (i = 0; i < diff_queued_diff.nr; i++) { + struct diff_filepair *p = diff_queued_diff.queue[i]; + if ((p->status == 'R' || p->status == 'C') && + !strcmp(p->two->path, origin->path)) { + porigin = get_origin(parent, p->one->path); + oidcpy(&porigin->blob_oid, &p->one->oid); + porigin->mode = p->one->mode; + break; + } + } + diff_flush(&diff_opts); + clear_pathspec(&diff_opts.pathspec); + return porigin; +} + +/* + * Append a new blame entry to a given output queue. + */ +static void add_blame_entry(struct blame_entry ***queue, + const struct blame_entry *src) +{ + struct blame_entry *e = xmalloc(sizeof(*e)); + memcpy(e, src, sizeof(*e)); + blame_origin_incref(e->suspect); + + e->next = **queue; + **queue = e; + *queue = &e->next; +} + +/* + * src typically is on-stack; we want to copy the information in it to + * a malloced blame_entry that gets added to the given queue. The + * origin of dst loses a refcnt. + */ +static void dup_entry(struct blame_entry ***queue, + struct blame_entry *dst, struct blame_entry *src) +{ + blame_origin_incref(src->suspect); + blame_origin_decref(dst->suspect); + memcpy(dst, src, sizeof(*src)); + dst->next = **queue; + **queue = dst; + *queue = &dst->next; +} + +const char *blame_nth_line(struct blame_scoreboard *sb, long lno) +{ + return sb->final_buf + sb->lineno[lno]; +} + +/* + * It is known that lines between tlno to same came from parent, and e + * has an overlap with that range. it also is known that parent's + * line plno corresponds to e's line tlno. + * + * <---- e -----> + * <------> + * <------------> + * <------------> + * <------------------> + * + * Split e into potentially three parts; before this chunk, the chunk + * to be blamed for the parent, and after that portion. + */ +static void split_overlap(struct blame_entry *split, + struct blame_entry *e, + int tlno, int plno, int same, + struct blame_origin *parent) +{ + int chunk_end_lno; + memset(split, 0, sizeof(struct blame_entry [3])); + + if (e->s_lno < tlno) { + /* there is a pre-chunk part not blamed on parent */ + split[0].suspect = blame_origin_incref(e->suspect); + split[0].lno = e->lno; + split[0].s_lno = e->s_lno; + split[0].num_lines = tlno - e->s_lno; + split[1].lno = e->lno + tlno - e->s_lno; + split[1].s_lno = plno; + } + else { + split[1].lno = e->lno; + split[1].s_lno = plno + (e->s_lno - tlno); + } + + if (same < e->s_lno + e->num_lines) { + /* there is a post-chunk part not blamed on parent */ + split[2].suspect = blame_origin_incref(e->suspect); + split[2].lno = e->lno + (same - e->s_lno); + split[2].s_lno = e->s_lno + (same - e->s_lno); + split[2].num_lines = e->s_lno + e->num_lines - same; + chunk_end_lno = split[2].lno; + } + else + chunk_end_lno = e->lno + e->num_lines; + split[1].num_lines = chunk_end_lno - split[1].lno; + + /* + * if it turns out there is nothing to blame the parent for, + * forget about the splitting. !split[1].suspect signals this. + */ + if (split[1].num_lines < 1) + return; + split[1].suspect = blame_origin_incref(parent); +} + +/* + * split_overlap() divided an existing blame e into up to three parts + * in split. Any assigned blame is moved to queue to + * reflect the split. + */ +static void split_blame(struct blame_entry ***blamed, + struct blame_entry ***unblamed, + struct blame_entry *split, + struct blame_entry *e) +{ + if (split[0].suspect && split[2].suspect) { + /* The first part (reuse storage for the existing entry e) */ + dup_entry(unblamed, e, &split[0]); + + /* The last part -- me */ + add_blame_entry(unblamed, &split[2]); + + /* ... and the middle part -- parent */ + add_blame_entry(blamed, &split[1]); + } + else if (!split[0].suspect && !split[2].suspect) + /* + * The parent covers the entire area; reuse storage for + * e and replace it with the parent. + */ + dup_entry(blamed, e, &split[1]); + else if (split[0].suspect) { + /* me and then parent */ + dup_entry(unblamed, e, &split[0]); + add_blame_entry(blamed, &split[1]); + } + else { + /* parent and then me */ + dup_entry(blamed, e, &split[1]); + add_blame_entry(unblamed, &split[2]); + } +} + +/* + * After splitting the blame, the origins used by the + * on-stack blame_entry should lose one refcnt each. + */ +static void decref_split(struct blame_entry *split) +{ + int i; + + for (i = 0; i < 3; i++) + blame_origin_decref(split[i].suspect); +} + +/* + * reverse_blame reverses the list given in head, appending tail. + * That allows us to build lists in reverse order, then reverse them + * afterwards. This can be faster than building the list in proper + * order right away. The reason is that building in proper order + * requires writing a link in the _previous_ element, while building + * in reverse order just requires placing the list head into the + * _current_ element. + */ + +static struct blame_entry *reverse_blame(struct blame_entry *head, + struct blame_entry *tail) +{ + while (head) { + struct blame_entry *next = head->next; + head->next = tail; + tail = head; + head = next; + } + return tail; +} + +/* + * Process one hunk from the patch between the current suspect for + * blame_entry e and its parent. This first blames any unfinished + * entries before the chunk (which is where target and parent start + * differing) on the parent, and then splits blame entries at the + * start and at the end of the difference region. Since use of -M and + * -C options may lead to overlapping/duplicate source line number + * ranges, all we can rely on from sorting/merging is the order of the + * first suspect line number. + */ +static void blame_chunk(struct blame_entry ***dstq, struct blame_entry ***srcq, + int tlno, int offset, int same, + struct blame_origin *parent) +{ + struct blame_entry *e = **srcq; + struct blame_entry *samep = NULL, *diffp = NULL; + + while (e && e->s_lno < tlno) { + struct blame_entry *next = e->next; + /* + * current record starts before differing portion. If + * it reaches into it, we need to split it up and + * examine the second part separately. + */ + if (e->s_lno + e->num_lines > tlno) { + /* Move second half to a new record */ + int len = tlno - e->s_lno; + struct blame_entry *n = xcalloc(1, sizeof (struct blame_entry)); + n->suspect = e->suspect; + n->lno = e->lno + len; + n->s_lno = e->s_lno + len; + n->num_lines = e->num_lines - len; + e->num_lines = len; + e->score = 0; + /* Push new record to diffp */ + n->next = diffp; + diffp = n; + } else + blame_origin_decref(e->suspect); + /* Pass blame for everything before the differing + * chunk to the parent */ + e->suspect = blame_origin_incref(parent); + e->s_lno += offset; + e->next = samep; + samep = e; + e = next; + } + /* + * As we don't know how much of a common stretch after this + * diff will occur, the currently blamed parts are all that we + * can assign to the parent for now. + */ + + if (samep) { + **dstq = reverse_blame(samep, **dstq); + *dstq = &samep->next; + } + /* + * Prepend the split off portions: everything after e starts + * after the blameable portion. + */ + e = reverse_blame(diffp, e); + + /* + * Now retain records on the target while parts are different + * from the parent. + */ + samep = NULL; + diffp = NULL; + while (e && e->s_lno < same) { + struct blame_entry *next = e->next; + + /* + * If current record extends into sameness, need to split. + */ + if (e->s_lno + e->num_lines > same) { + /* + * Move second half to a new record to be + * processed by later chunks + */ + int len = same - e->s_lno; + struct blame_entry *n = xcalloc(1, sizeof (struct blame_entry)); + n->suspect = blame_origin_incref(e->suspect); + n->lno = e->lno + len; + n->s_lno = e->s_lno + len; + n->num_lines = e->num_lines - len; + e->num_lines = len; + e->score = 0; + /* Push new record to samep */ + n->next = samep; + samep = n; + } + e->next = diffp; + diffp = e; + e = next; + } + **srcq = reverse_blame(diffp, reverse_blame(samep, e)); + /* Move across elements that are in the unblamable portion */ + if (diffp) + *srcq = &diffp->next; +} + +struct blame_chunk_cb_data { + struct blame_origin *parent; + long offset; + struct blame_entry **dstq; + struct blame_entry **srcq; +}; + +/* diff chunks are from parent to target */ +static int blame_chunk_cb(long start_a, long count_a, + long start_b, long count_b, void *data) +{ + struct blame_chunk_cb_data *d = data; + if (start_a - start_b != d->offset) + die("internal error in blame::blame_chunk_cb"); + blame_chunk(&d->dstq, &d->srcq, start_b, start_a - start_b, + start_b + count_b, d->parent); + d->offset = start_a + count_a - (start_b + count_b); + return 0; +} + +/* + * We are looking at the origin 'target' and aiming to pass blame + * for the lines it is suspected to its parent. Run diff to find + * which lines came from parent and pass blame for them. + */ +static void pass_blame_to_parent(struct blame_scoreboard *sb, + struct blame_origin *target, + struct blame_origin *parent) +{ + mmfile_t file_p, file_o; + struct blame_chunk_cb_data d; + struct blame_entry *newdest = NULL; + + if (!target->suspects) + return; /* nothing remains for this target */ + + d.parent = parent; + d.offset = 0; + d.dstq = &newdest; d.srcq = &target->suspects; + + fill_origin_blob(&sb->revs->diffopt, parent, &file_p, &sb->num_read_blob); + fill_origin_blob(&sb->revs->diffopt, target, &file_o, &sb->num_read_blob); + sb->num_get_patch++; + + if (diff_hunks(&file_p, &file_o, blame_chunk_cb, &d, sb->xdl_opts)) + die("unable to generate diff (%s -> %s)", + oid_to_hex(&parent->commit->object.oid), + oid_to_hex(&target->commit->object.oid)); + /* The rest are the same as the parent */ + blame_chunk(&d.dstq, &d.srcq, INT_MAX, d.offset, INT_MAX, parent); + *d.dstq = NULL; + queue_blames(sb, parent, newdest); + + return; +} + +/* + * The lines in blame_entry after splitting blames many times can become + * very small and trivial, and at some point it becomes pointless to + * blame the parents. E.g. "\t\t}\n\t}\n\n" appears everywhere in any + * ordinary C program, and it is not worth to say it was copied from + * totally unrelated file in the parent. + * + * Compute how trivial the lines in the blame_entry are. + */ +unsigned blame_entry_score(struct blame_scoreboard *sb, struct blame_entry *e) +{ + unsigned score; + const char *cp, *ep; + + if (e->score) + return e->score; + + score = 1; + cp = blame_nth_line(sb, e->lno); + ep = blame_nth_line(sb, e->lno + e->num_lines); + while (cp < ep) { + unsigned ch = *((unsigned char *)cp); + if (isalnum(ch)) + score++; + cp++; + } + e->score = score; + return score; +} + +/* + * best_so_far[] and potential[] are both a split of an existing blame_entry + * that passes blame to the parent. Maintain best_so_far the best split so + * far, by comparing potential and best_so_far and copying potential into + * bst_so_far as needed. + */ +static void copy_split_if_better(struct blame_scoreboard *sb, + struct blame_entry *best_so_far, + struct blame_entry *potential) +{ + int i; + + if (!potential[1].suspect) + return; + if (best_so_far[1].suspect) { + if (blame_entry_score(sb, &potential[1]) < + blame_entry_score(sb, &best_so_far[1])) + return; + } + + for (i = 0; i < 3; i++) + blame_origin_incref(potential[i].suspect); + decref_split(best_so_far); + memcpy(best_so_far, potential, sizeof(struct blame_entry[3])); +} + +/* + * We are looking at a part of the final image represented by + * ent (tlno and same are offset by ent->s_lno). + * tlno is where we are looking at in the final image. + * up to (but not including) same match preimage. + * plno is where we are looking at in the preimage. + * + * <-------------- final image ----------------------> + * <------ent------> + * ^tlno ^same + * <---------preimage-----> + * ^plno + * + * All line numbers are 0-based. + */ +static void handle_split(struct blame_scoreboard *sb, + struct blame_entry *ent, + int tlno, int plno, int same, + struct blame_origin *parent, + struct blame_entry *split) +{ + if (ent->num_lines <= tlno) + return; + if (tlno < same) { + struct blame_entry potential[3]; + tlno += ent->s_lno; + same += ent->s_lno; + split_overlap(potential, ent, tlno, plno, same, parent); + copy_split_if_better(sb, split, potential); + decref_split(potential); + } +} + +struct handle_split_cb_data { + struct blame_scoreboard *sb; + struct blame_entry *ent; + struct blame_origin *parent; + struct blame_entry *split; + long plno; + long tlno; +}; + +static int handle_split_cb(long start_a, long count_a, + long start_b, long count_b, void *data) +{ + struct handle_split_cb_data *d = data; + handle_split(d->sb, d->ent, d->tlno, d->plno, start_b, d->parent, + d->split); + d->plno = start_a + count_a; + d->tlno = start_b + count_b; + return 0; +} + +/* + * Find the lines from parent that are the same as ent so that + * we can pass blames to it. file_p has the blob contents for + * the parent. + */ +static void find_copy_in_blob(struct blame_scoreboard *sb, + struct blame_entry *ent, + struct blame_origin *parent, + struct blame_entry *split, + mmfile_t *file_p) +{ + const char *cp; + mmfile_t file_o; + struct handle_split_cb_data d; + + memset(&d, 0, sizeof(d)); + d.sb = sb; d.ent = ent; d.parent = parent; d.split = split; + /* + * Prepare mmfile that contains only the lines in ent. + */ + cp = blame_nth_line(sb, ent->lno); + file_o.ptr = (char *) cp; + file_o.size = blame_nth_line(sb, ent->lno + ent->num_lines) - cp; + + /* + * file_o is a part of final image we are annotating. + * file_p partially may match that image. + */ + memset(split, 0, sizeof(struct blame_entry [3])); + if (diff_hunks(file_p, &file_o, handle_split_cb, &d, sb->xdl_opts)) + die("unable to generate diff (%s)", + oid_to_hex(&parent->commit->object.oid)); + /* remainder, if any, all match the preimage */ + handle_split(sb, ent, d.tlno, d.plno, ent->num_lines, parent, split); +} + +/* Move all blame entries from list *source that have a score smaller + * than score_min to the front of list *small. + * Returns a pointer to the link pointing to the old head of the small list. + */ + +static struct blame_entry **filter_small(struct blame_scoreboard *sb, + struct blame_entry **small, + struct blame_entry **source, + unsigned score_min) +{ + struct blame_entry *p = *source; + struct blame_entry *oldsmall = *small; + while (p) { + if (blame_entry_score(sb, p) <= score_min) { + *small = p; + small = &p->next; + p = *small; + } else { + *source = p; + source = &p->next; + p = *source; + } + } + *small = oldsmall; + *source = NULL; + return small; +} + +/* + * See if lines currently target is suspected for can be attributed to + * parent. + */ +static void find_move_in_parent(struct blame_scoreboard *sb, + struct blame_entry ***blamed, + struct blame_entry **toosmall, + struct blame_origin *target, + struct blame_origin *parent) +{ + struct blame_entry *e, split[3]; + struct blame_entry *unblamed = target->suspects; + struct blame_entry *leftover = NULL; + mmfile_t file_p; + + if (!unblamed) + return; /* nothing remains for this target */ + + fill_origin_blob(&sb->revs->diffopt, parent, &file_p, &sb->num_read_blob); + if (!file_p.ptr) + return; + + /* At each iteration, unblamed has a NULL-terminated list of + * entries that have not yet been tested for blame. leftover + * contains the reversed list of entries that have been tested + * without being assignable to the parent. + */ + do { + struct blame_entry **unblamedtail = &unblamed; + struct blame_entry *next; + for (e = unblamed; e; e = next) { + next = e->next; + find_copy_in_blob(sb, e, parent, split, &file_p); + if (split[1].suspect && + sb->move_score < blame_entry_score(sb, &split[1])) { + split_blame(blamed, &unblamedtail, split, e); + } else { + e->next = leftover; + leftover = e; + } + decref_split(split); + } + *unblamedtail = NULL; + toosmall = filter_small(sb, toosmall, &unblamed, sb->move_score); + } while (unblamed); + target->suspects = reverse_blame(leftover, NULL); +} + +struct blame_list { + struct blame_entry *ent; + struct blame_entry split[3]; +}; + +/* + * Count the number of entries the target is suspected for, + * and prepare a list of entry and the best split. + */ +static struct blame_list *setup_blame_list(struct blame_entry *unblamed, + int *num_ents_p) +{ + struct blame_entry *e; + int num_ents, i; + struct blame_list *blame_list = NULL; + + for (e = unblamed, num_ents = 0; e; e = e->next) + num_ents++; + if (num_ents) { + blame_list = xcalloc(num_ents, sizeof(struct blame_list)); + for (e = unblamed, i = 0; e; e = e->next) + blame_list[i++].ent = e; + } + *num_ents_p = num_ents; + return blame_list; +} + +/* + * For lines target is suspected for, see if we can find code movement + * across file boundary from the parent commit. porigin is the path + * in the parent we already tried. + */ +static void find_copy_in_parent(struct blame_scoreboard *sb, + struct blame_entry ***blamed, + struct blame_entry **toosmall, + struct blame_origin *target, + struct commit *parent, + struct blame_origin *porigin, + int opt) +{ + struct diff_options diff_opts; + int i, j; + struct blame_list *blame_list; + int num_ents; + struct blame_entry *unblamed = target->suspects; + struct blame_entry *leftover = NULL; + + if (!unblamed) + return; /* nothing remains for this target */ + + repo_diff_setup(sb->repo, &diff_opts); + diff_opts.flags.recursive = 1; + diff_opts.output_format = DIFF_FORMAT_NO_OUTPUT; + + diff_setup_done(&diff_opts); + + /* Try "find copies harder" on new path if requested; + * we do not want to use diffcore_rename() actually to + * match things up; find_copies_harder is set only to + * force diff_tree_oid() to feed all filepairs to diff_queue, + * and this code needs to be after diff_setup_done(), which + * usually makes find-copies-harder imply copy detection. + */ + if ((opt & PICKAXE_BLAME_COPY_HARDEST) + || ((opt & PICKAXE_BLAME_COPY_HARDER) + && (!porigin || strcmp(target->path, porigin->path)))) + diff_opts.flags.find_copies_harder = 1; + + if (is_null_oid(&target->commit->object.oid)) + do_diff_cache(get_commit_tree_oid(parent), &diff_opts); + else + diff_tree_oid(get_commit_tree_oid(parent), + get_commit_tree_oid(target->commit), + "", &diff_opts); + + if (!diff_opts.flags.find_copies_harder) + diffcore_std(&diff_opts); + + do { + struct blame_entry **unblamedtail = &unblamed; + blame_list = setup_blame_list(unblamed, &num_ents); + + for (i = 0; i < diff_queued_diff.nr; i++) { + struct diff_filepair *p = diff_queued_diff.queue[i]; + struct blame_origin *norigin; + mmfile_t file_p; + struct blame_entry potential[3]; + + if (!DIFF_FILE_VALID(p->one)) + continue; /* does not exist in parent */ + if (S_ISGITLINK(p->one->mode)) + continue; /* ignore git links */ + if (porigin && !strcmp(p->one->path, porigin->path)) + /* find_move already dealt with this path */ + continue; + + norigin = get_origin(parent, p->one->path); + oidcpy(&norigin->blob_oid, &p->one->oid); + norigin->mode = p->one->mode; + fill_origin_blob(&sb->revs->diffopt, norigin, &file_p, &sb->num_read_blob); + if (!file_p.ptr) + continue; + + for (j = 0; j < num_ents; j++) { + find_copy_in_blob(sb, blame_list[j].ent, + norigin, potential, &file_p); + copy_split_if_better(sb, blame_list[j].split, + potential); + decref_split(potential); + } + blame_origin_decref(norigin); + } + + for (j = 0; j < num_ents; j++) { + struct blame_entry *split = blame_list[j].split; + if (split[1].suspect && + sb->copy_score < blame_entry_score(sb, &split[1])) { + split_blame(blamed, &unblamedtail, split, + blame_list[j].ent); + } else { + blame_list[j].ent->next = leftover; + leftover = blame_list[j].ent; + } + decref_split(split); + } + free(blame_list); + *unblamedtail = NULL; + toosmall = filter_small(sb, toosmall, &unblamed, sb->copy_score); + } while (unblamed); + target->suspects = reverse_blame(leftover, NULL); + diff_flush(&diff_opts); + clear_pathspec(&diff_opts.pathspec); +} + +/* + * The blobs of origin and porigin exactly match, so everything + * origin is suspected for can be blamed on the parent. + */ +static void pass_whole_blame(struct blame_scoreboard *sb, + struct blame_origin *origin, struct blame_origin *porigin) +{ + struct blame_entry *e, *suspects; + + if (!porigin->file.ptr && origin->file.ptr) { + /* Steal its file */ + porigin->file = origin->file; + origin->file.ptr = NULL; + } + suspects = origin->suspects; + origin->suspects = NULL; + for (e = suspects; e; e = e->next) { + blame_origin_incref(porigin); + blame_origin_decref(e->suspect); + e->suspect = porigin; + } + queue_blames(sb, porigin, suspects); +} + +/* + * We pass blame from the current commit to its parents. We keep saying + * "parent" (and "porigin"), but what we mean is to find scapegoat to + * exonerate ourselves. + */ +static struct commit_list *first_scapegoat(struct rev_info *revs, struct commit *commit, + int reverse) +{ + if (!reverse) { + if (revs->first_parent_only && + commit->parents && + commit->parents->next) { + free_commit_list(commit->parents->next); + commit->parents->next = NULL; + } + return commit->parents; + } + return lookup_decoration(&revs->children, &commit->object); +} + +static int num_scapegoats(struct rev_info *revs, struct commit *commit, int reverse) +{ + struct commit_list *l = first_scapegoat(revs, commit, reverse); + return commit_list_count(l); +} + +/* Distribute collected unsorted blames to the respected sorted lists + * in the various origins. + */ +static void distribute_blame(struct blame_scoreboard *sb, struct blame_entry *blamed) +{ + blamed = llist_mergesort(blamed, get_next_blame, set_next_blame, + compare_blame_suspect); + while (blamed) + { + struct blame_origin *porigin = blamed->suspect; + struct blame_entry *suspects = NULL; + do { + struct blame_entry *next = blamed->next; + blamed->next = suspects; + suspects = blamed; + blamed = next; + } while (blamed && blamed->suspect == porigin); + suspects = reverse_blame(suspects, NULL); + queue_blames(sb, porigin, suspects); + } +} + +#define MAXSG 16 + +static void pass_blame(struct blame_scoreboard *sb, struct blame_origin *origin, int opt) +{ + struct rev_info *revs = sb->revs; + int i, pass, num_sg; + struct commit *commit = origin->commit; + struct commit_list *sg; + struct blame_origin *sg_buf[MAXSG]; + struct blame_origin *porigin, **sg_origin = sg_buf; + struct blame_entry *toosmall = NULL; + struct blame_entry *blames, **blametail = &blames; + + num_sg = num_scapegoats(revs, commit, sb->reverse); + if (!num_sg) + goto finish; + else if (num_sg < ARRAY_SIZE(sg_buf)) + memset(sg_buf, 0, sizeof(sg_buf)); + else + sg_origin = xcalloc(num_sg, sizeof(*sg_origin)); + + /* + * The first pass looks for unrenamed path to optimize for + * common cases, then we look for renames in the second pass. + */ + for (pass = 0; pass < 2 - sb->no_whole_file_rename; pass++) { + struct blame_origin *(*find)(struct repository *, struct commit *, struct blame_origin *); + find = pass ? find_rename : find_origin; + + for (i = 0, sg = first_scapegoat(revs, commit, sb->reverse); + i < num_sg && sg; + sg = sg->next, i++) { + struct commit *p = sg->item; + int j, same; + + if (sg_origin[i]) + continue; + if (parse_commit(p)) + continue; + porigin = find(sb->repo, p, origin); + if (!porigin) + continue; + if (oideq(&porigin->blob_oid, &origin->blob_oid)) { + pass_whole_blame(sb, origin, porigin); + blame_origin_decref(porigin); + goto finish; + } + for (j = same = 0; j < i; j++) + if (sg_origin[j] && + oideq(&sg_origin[j]->blob_oid, &porigin->blob_oid)) { + same = 1; + break; + } + if (!same) + sg_origin[i] = porigin; + else + blame_origin_decref(porigin); + } + } + + sb->num_commits++; + for (i = 0, sg = first_scapegoat(revs, commit, sb->reverse); + i < num_sg && sg; + sg = sg->next, i++) { + struct blame_origin *porigin = sg_origin[i]; + if (!porigin) + continue; + if (!origin->previous) { + blame_origin_incref(porigin); + origin->previous = porigin; + } + pass_blame_to_parent(sb, origin, porigin); + if (!origin->suspects) + goto finish; + } + + /* + * Optionally find moves in parents' files. + */ + if (opt & PICKAXE_BLAME_MOVE) { + filter_small(sb, &toosmall, &origin->suspects, sb->move_score); + if (origin->suspects) { + for (i = 0, sg = first_scapegoat(revs, commit, sb->reverse); + i < num_sg && sg; + sg = sg->next, i++) { + struct blame_origin *porigin = sg_origin[i]; + if (!porigin) + continue; + find_move_in_parent(sb, &blametail, &toosmall, origin, porigin); + if (!origin->suspects) + break; + } + } + } + + /* + * Optionally find copies from parents' files. + */ + if (opt & PICKAXE_BLAME_COPY) { + if (sb->copy_score > sb->move_score) + filter_small(sb, &toosmall, &origin->suspects, sb->copy_score); + else if (sb->copy_score < sb->move_score) { + origin->suspects = blame_merge(origin->suspects, toosmall); + toosmall = NULL; + filter_small(sb, &toosmall, &origin->suspects, sb->copy_score); + } + if (!origin->suspects) + goto finish; + + for (i = 0, sg = first_scapegoat(revs, commit, sb->reverse); + i < num_sg && sg; + sg = sg->next, i++) { + struct blame_origin *porigin = sg_origin[i]; + find_copy_in_parent(sb, &blametail, &toosmall, + origin, sg->item, porigin, opt); + if (!origin->suspects) + goto finish; + } + } + +finish: + *blametail = NULL; + distribute_blame(sb, blames); + /* + * prepend toosmall to origin->suspects + * + * There is no point in sorting: this ends up on a big + * unsorted list in the caller anyway. + */ + if (toosmall) { + struct blame_entry **tail = &toosmall; + while (*tail) + tail = &(*tail)->next; + *tail = origin->suspects; + origin->suspects = toosmall; + } + for (i = 0; i < num_sg; i++) { + if (sg_origin[i]) { + drop_origin_blob(sg_origin[i]); + blame_origin_decref(sg_origin[i]); + } + } + drop_origin_blob(origin); + if (sg_buf != sg_origin) + free(sg_origin); +} + +/* + * The main loop -- while we have blobs with lines whose true origin + * is still unknown, pick one blob, and allow its lines to pass blames + * to its parents. */ +void assign_blame(struct blame_scoreboard *sb, int opt) +{ + struct rev_info *revs = sb->revs; + struct commit *commit = prio_queue_get(&sb->commits); + + while (commit) { + struct blame_entry *ent; + struct blame_origin *suspect = get_blame_suspects(commit); + + /* find one suspect to break down */ + while (suspect && !suspect->suspects) + suspect = suspect->next; + + if (!suspect) { + commit = prio_queue_get(&sb->commits); + continue; + } + + assert(commit == suspect->commit); + + /* + * We will use this suspect later in the loop, + * so hold onto it in the meantime. + */ + blame_origin_incref(suspect); + parse_commit(commit); + if (sb->reverse || + (!(commit->object.flags & UNINTERESTING) && + !(revs->max_age != -1 && commit->date < revs->max_age))) + pass_blame(sb, suspect, opt); + else { + commit->object.flags |= UNINTERESTING; + if (commit->object.parsed) + mark_parents_uninteresting(commit); + } + /* treat root commit as boundary */ + if (!commit->parents && !sb->show_root) + commit->object.flags |= UNINTERESTING; + + /* Take responsibility for the remaining entries */ + ent = suspect->suspects; + if (ent) { + suspect->guilty = 1; + for (;;) { + struct blame_entry *next = ent->next; + if (sb->found_guilty_entry) + sb->found_guilty_entry(ent, sb->found_guilty_entry_data); + if (next) { + ent = next; + continue; + } + ent->next = sb->ent; + sb->ent = suspect->suspects; + suspect->suspects = NULL; + break; + } + } + blame_origin_decref(suspect); + + if (sb->debug) /* sanity */ + sanity_check_refcnt(sb); + } +} + +static const char *get_next_line(const char *start, const char *end) +{ + const char *nl = memchr(start, '\n', end - start); + return nl ? nl + 1 : end; +} + +/* + * To allow quick access to the contents of nth line in the + * final image, prepare an index in the scoreboard. + */ +static int prepare_lines(struct blame_scoreboard *sb) +{ + const char *buf = sb->final_buf; + unsigned long len = sb->final_buf_size; + const char *end = buf + len; + const char *p; + int *lineno; + int num = 0; + + for (p = buf; p < end; p = get_next_line(p, end)) + num++; + + ALLOC_ARRAY(sb->lineno, num + 1); + lineno = sb->lineno; + + for (p = buf; p < end; p = get_next_line(p, end)) + *lineno++ = p - buf; + + *lineno = len; + + sb->num_lines = num; + return sb->num_lines; +} + +static struct commit *find_single_final(struct rev_info *revs, + const char **name_p) +{ + int i; + struct commit *found = NULL; + const char *name = NULL; + + for (i = 0; i < revs->pending.nr; i++) { + struct object *obj = revs->pending.objects[i].item; + if (obj->flags & UNINTERESTING) + continue; + obj = deref_tag(revs->repo, obj, NULL, 0); + if (obj->type != OBJ_COMMIT) + die("Non commit %s?", revs->pending.objects[i].name); + if (found) + die("More than one commit to dig from %s and %s?", + revs->pending.objects[i].name, name); + found = (struct commit *)obj; + name = revs->pending.objects[i].name; + } + if (name_p) + *name_p = xstrdup_or_null(name); + return found; +} + +static struct commit *dwim_reverse_initial(struct rev_info *revs, + const char **name_p) +{ + /* + * DWIM "git blame --reverse ONE -- PATH" as + * "git blame --reverse ONE..HEAD -- PATH" but only do so + * when it makes sense. + */ + struct object *obj; + struct commit *head_commit; + struct object_id head_oid; + + if (revs->pending.nr != 1) + return NULL; + + /* Is that sole rev a committish? */ + obj = revs->pending.objects[0].item; + obj = deref_tag(revs->repo, obj, NULL, 0); + if (obj->type != OBJ_COMMIT) + return NULL; + + /* Do we have HEAD? */ + if (!resolve_ref_unsafe("HEAD", RESOLVE_REF_READING, &head_oid, NULL)) + return NULL; + head_commit = lookup_commit_reference_gently(revs->repo, + &head_oid, 1); + if (!head_commit) + return NULL; + + /* Turn "ONE" into "ONE..HEAD" then */ + obj->flags |= UNINTERESTING; + add_pending_object(revs, &head_commit->object, "HEAD"); + + if (name_p) + *name_p = revs->pending.objects[0].name; + return (struct commit *)obj; +} + +static struct commit *find_single_initial(struct rev_info *revs, + const char **name_p) +{ + int i; + struct commit *found = NULL; + const char *name = NULL; + + /* + * There must be one and only one negative commit, and it must be + * the boundary. + */ + for (i = 0; i < revs->pending.nr; i++) { + struct object *obj = revs->pending.objects[i].item; + if (!(obj->flags & UNINTERESTING)) + continue; + obj = deref_tag(revs->repo, obj, NULL, 0); + if (obj->type != OBJ_COMMIT) + die("Non commit %s?", revs->pending.objects[i].name); + if (found) + die("More than one commit to dig up from, %s and %s?", + revs->pending.objects[i].name, name); + found = (struct commit *) obj; + name = revs->pending.objects[i].name; + } + + if (!name) + found = dwim_reverse_initial(revs, &name); + if (!name) + die("No commit to dig up from?"); + + if (name_p) + *name_p = xstrdup(name); + return found; +} + +void init_scoreboard(struct blame_scoreboard *sb) +{ + memset(sb, 0, sizeof(struct blame_scoreboard)); + sb->move_score = BLAME_DEFAULT_MOVE_SCORE; + sb->copy_score = BLAME_DEFAULT_COPY_SCORE; +} + +void setup_scoreboard(struct blame_scoreboard *sb, + const char *path, + struct blame_origin **orig) +{ + const char *final_commit_name = NULL; + struct blame_origin *o; + struct commit *final_commit = NULL; + enum object_type type; + + init_blame_suspects(&blame_suspects); + + if (sb->reverse && sb->contents_from) + die(_("--contents and --reverse do not blend well.")); + + if (!sb->repo) + BUG("repo is NULL"); + + if (!sb->reverse) { + sb->final = find_single_final(sb->revs, &final_commit_name); + sb->commits.compare = compare_commits_by_commit_date; + } else { + sb->final = find_single_initial(sb->revs, &final_commit_name); + sb->commits.compare = compare_commits_by_reverse_commit_date; + } + + if (sb->final && sb->contents_from) + die(_("cannot use --contents with final commit object name")); + + if (sb->reverse && sb->revs->first_parent_only) + sb->revs->children.name = NULL; + + if (!sb->final) { + /* + * "--not A B -- path" without anything positive; + * do not default to HEAD, but use the working tree + * or "--contents". + */ + setup_work_tree(); + sb->final = fake_working_tree_commit(sb->repo, + &sb->revs->diffopt, + path, sb->contents_from); + add_pending_object(sb->revs, &(sb->final->object), ":"); + } + + if (sb->reverse && sb->revs->first_parent_only) { + final_commit = find_single_final(sb->revs, NULL); + if (!final_commit) + die(_("--reverse and --first-parent together require specified latest commit")); + } + + /* + * If we have bottom, this will mark the ancestors of the + * bottom commits we would reach while traversing as + * uninteresting. + */ + if (prepare_revision_walk(sb->revs)) + die(_("revision walk setup failed")); + + if (sb->reverse && sb->revs->first_parent_only) { + struct commit *c = final_commit; + + sb->revs->children.name = "children"; + while (c->parents && + !oideq(&c->object.oid, &sb->final->object.oid)) { + struct commit_list *l = xcalloc(1, sizeof(*l)); + + l->item = c; + if (add_decoration(&sb->revs->children, + &c->parents->item->object, l)) + BUG("not unique item in first-parent chain"); + c = c->parents->item; + } + + if (!oideq(&c->object.oid, &sb->final->object.oid)) + die(_("--reverse --first-parent together require range along first-parent chain")); + } + + if (is_null_oid(&sb->final->object.oid)) { + o = get_blame_suspects(sb->final); + sb->final_buf = xmemdupz(o->file.ptr, o->file.size); + sb->final_buf_size = o->file.size; + } + else { + o = get_origin(sb->final, path); + if (fill_blob_sha1_and_mode(sb->repo, o)) + die(_("no such path %s in %s"), path, final_commit_name); + + if (sb->revs->diffopt.flags.allow_textconv && + textconv_object(sb->repo, path, o->mode, &o->blob_oid, 1, (char **) &sb->final_buf, + &sb->final_buf_size)) + ; + else + sb->final_buf = read_object_file(&o->blob_oid, &type, + &sb->final_buf_size); + + if (!sb->final_buf) + die(_("cannot read blob %s for path %s"), + oid_to_hex(&o->blob_oid), + path); + } + sb->num_read_blob++; + prepare_lines(sb); + + if (orig) + *orig = o; + + free((char *)final_commit_name); +} + + + +struct blame_entry *blame_entry_prepend(struct blame_entry *head, + long start, long end, + struct blame_origin *o) +{ + struct blame_entry *new_head = xcalloc(1, sizeof(struct blame_entry)); + new_head->lno = start; + new_head->num_lines = end - start; + new_head->suspect = o; + new_head->s_lno = start; + new_head->next = head; + blame_origin_incref(o); + return new_head; +} |