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-rw-r--r--blame.c2915
1 files changed, 2915 insertions, 0 deletions
diff --git a/blame.c b/blame.c
new file mode 100644
index 0000000..8bfeaa1
--- /dev/null
+++ b/blame.c
@@ -0,0 +1,2915 @@
+#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"
+#include "bloom.h"
+#include "commit-graph.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 short mode;
+
+ if (!get_tree_entry(r, 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 (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;
+
+ repo_read_index(r);
+ 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",
+ WANT_BLANK_IDENT, 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);
+ repo_read_index(r);
+
+ 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);
+}
+
+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;
+}
+
+static int find_line_starts(int **line_starts, const char *buf,
+ unsigned long len)
+{
+ 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(*line_starts, num + 1);
+ lineno = *line_starts;
+
+ for (p = buf; p < end; p = get_next_line(p, end))
+ *lineno++ = p - buf;
+
+ *lineno = len;
+
+ return num;
+}
+
+struct fingerprint_entry;
+
+/* A fingerprint is intended to loosely represent a string, such that two
+ * fingerprints can be quickly compared to give an indication of the similarity
+ * of the strings that they represent.
+ *
+ * A fingerprint is represented as a multiset of the lower-cased byte pairs in
+ * the string that it represents. Whitespace is added at each end of the
+ * string. Whitespace pairs are ignored. Whitespace is converted to '\0'.
+ * For example, the string "Darth Radar" will be converted to the following
+ * fingerprint:
+ * {"\0d", "da", "da", "ar", "ar", "rt", "th", "h\0", "\0r", "ra", "ad", "r\0"}
+ *
+ * The similarity between two fingerprints is the size of the intersection of
+ * their multisets, including repeated elements. See fingerprint_similarity for
+ * examples.
+ *
+ * For ease of implementation, the fingerprint is implemented as a map
+ * of byte pairs to the count of that byte pair in the string, instead of
+ * allowing repeated elements in a set.
+ */
+struct fingerprint {
+ struct hashmap map;
+ /* As we know the maximum number of entries in advance, it's
+ * convenient to store the entries in a single array instead of having
+ * the hashmap manage the memory.
+ */
+ struct fingerprint_entry *entries;
+};
+
+/* A byte pair in a fingerprint. Stores the number of times the byte pair
+ * occurs in the string that the fingerprint represents.
+ */
+struct fingerprint_entry {
+ /* The hashmap entry - the hash represents the byte pair in its
+ * entirety so we don't need to store the byte pair separately.
+ */
+ struct hashmap_entry entry;
+ /* The number of times the byte pair occurs in the string that the
+ * fingerprint represents.
+ */
+ int count;
+};
+
+/* See `struct fingerprint` for an explanation of what a fingerprint is.
+ * \param result the fingerprint of the string is stored here. This must be
+ * freed later using free_fingerprint.
+ * \param line_begin the start of the string
+ * \param line_end the end of the string
+ */
+static void get_fingerprint(struct fingerprint *result,
+ const char *line_begin,
+ const char *line_end)
+{
+ unsigned int hash, c0 = 0, c1;
+ const char *p;
+ int max_map_entry_count = 1 + line_end - line_begin;
+ struct fingerprint_entry *entry = xcalloc(max_map_entry_count,
+ sizeof(struct fingerprint_entry));
+ struct fingerprint_entry *found_entry;
+
+ hashmap_init(&result->map, NULL, NULL, max_map_entry_count);
+ result->entries = entry;
+ for (p = line_begin; p <= line_end; ++p, c0 = c1) {
+ /* Always terminate the string with whitespace.
+ * Normalise whitespace to 0, and normalise letters to
+ * lower case. This won't work for multibyte characters but at
+ * worst will match some unrelated characters.
+ */
+ if ((p == line_end) || isspace(*p))
+ c1 = 0;
+ else
+ c1 = tolower(*p);
+ hash = c0 | (c1 << 8);
+ /* Ignore whitespace pairs */
+ if (hash == 0)
+ continue;
+ hashmap_entry_init(&entry->entry, hash);
+
+ found_entry = hashmap_get_entry(&result->map, entry,
+ /* member name */ entry, NULL);
+ if (found_entry) {
+ found_entry->count += 1;
+ } else {
+ entry->count = 1;
+ hashmap_add(&result->map, &entry->entry);
+ ++entry;
+ }
+ }
+}
+
+static void free_fingerprint(struct fingerprint *f)
+{
+ hashmap_clear(&f->map);
+ free(f->entries);
+}
+
+/* Calculates the similarity between two fingerprints as the size of the
+ * intersection of their multisets, including repeated elements. See
+ * `struct fingerprint` for an explanation of the fingerprint representation.
+ * The similarity between "cat mat" and "father rather" is 2 because "at" is
+ * present twice in both strings while the similarity between "tim" and "mit"
+ * is 0.
+ */
+static int fingerprint_similarity(struct fingerprint *a, struct fingerprint *b)
+{
+ int intersection = 0;
+ struct hashmap_iter iter;
+ const struct fingerprint_entry *entry_a, *entry_b;
+
+ hashmap_for_each_entry(&b->map, &iter, entry_b,
+ entry /* member name */) {
+ entry_a = hashmap_get_entry(&a->map, entry_b, entry, NULL);
+ if (entry_a) {
+ intersection += entry_a->count < entry_b->count ?
+ entry_a->count : entry_b->count;
+ }
+ }
+ return intersection;
+}
+
+/* Subtracts byte-pair elements in B from A, modifying A in place.
+ */
+static void fingerprint_subtract(struct fingerprint *a, struct fingerprint *b)
+{
+ struct hashmap_iter iter;
+ struct fingerprint_entry *entry_a;
+ const struct fingerprint_entry *entry_b;
+
+ hashmap_iter_init(&b->map, &iter);
+
+ hashmap_for_each_entry(&b->map, &iter, entry_b,
+ entry /* member name */) {
+ entry_a = hashmap_get_entry(&a->map, entry_b, entry, NULL);
+ if (entry_a) {
+ if (entry_a->count <= entry_b->count)
+ hashmap_remove(&a->map, &entry_b->entry, NULL);
+ else
+ entry_a->count -= entry_b->count;
+ }
+ }
+}
+
+/* Calculate fingerprints for a series of lines.
+ * Puts the fingerprints in the fingerprints array, which must have been
+ * preallocated to allow storing line_count elements.
+ */
+static void get_line_fingerprints(struct fingerprint *fingerprints,
+ const char *content, const int *line_starts,
+ long first_line, long line_count)
+{
+ int i;
+ const char *linestart, *lineend;
+
+ line_starts += first_line;
+ for (i = 0; i < line_count; ++i) {
+ linestart = content + line_starts[i];
+ lineend = content + line_starts[i + 1];
+ get_fingerprint(fingerprints + i, linestart, lineend);
+ }
+}
+
+static void free_line_fingerprints(struct fingerprint *fingerprints,
+ int nr_fingerprints)
+{
+ int i;
+
+ for (i = 0; i < nr_fingerprints; i++)
+ free_fingerprint(&fingerprints[i]);
+}
+
+/* This contains the data necessary to linearly map a line number in one half
+ * of a diff chunk to the line in the other half of the diff chunk that is
+ * closest in terms of its position as a fraction of the length of the chunk.
+ */
+struct line_number_mapping {
+ int destination_start, destination_length,
+ source_start, source_length;
+};
+
+/* Given a line number in one range, offset and scale it to map it onto the
+ * other range.
+ * Essentially this mapping is a simple linear equation but the calculation is
+ * more complicated to allow performing it with integer operations.
+ * Another complication is that if a line could map onto many lines in the
+ * destination range then we want to choose the line at the center of those
+ * possibilities.
+ * Example: if the chunk is 2 lines long in A and 10 lines long in B then the
+ * first 5 lines in B will map onto the first line in the A chunk, while the
+ * last 5 lines will all map onto the second line in the A chunk.
+ * Example: if the chunk is 10 lines long in A and 2 lines long in B then line
+ * 0 in B will map onto line 2 in A, and line 1 in B will map onto line 7 in A.
+ */
+static int map_line_number(int line_number,
+ const struct line_number_mapping *mapping)
+{
+ return ((line_number - mapping->source_start) * 2 + 1) *
+ mapping->destination_length /
+ (mapping->source_length * 2) +
+ mapping->destination_start;
+}
+
+/* Get a pointer to the element storing the similarity between a line in A
+ * and a line in B.
+ *
+ * The similarities are stored in a 2-dimensional array. Each "row" in the
+ * array contains the similarities for a line in B. The similarities stored in
+ * a row are the similarities between the line in B and the nearby lines in A.
+ * To keep the length of each row the same, it is padded out with values of -1
+ * where the search range extends beyond the lines in A.
+ * For example, if max_search_distance_a is 2 and the two sides of a diff chunk
+ * look like this:
+ * a | m
+ * b | n
+ * c | o
+ * d | p
+ * e | q
+ * Then the similarity array will contain:
+ * [-1, -1, am, bm, cm,
+ * -1, an, bn, cn, dn,
+ * ao, bo, co, do, eo,
+ * bp, cp, dp, ep, -1,
+ * cq, dq, eq, -1, -1]
+ * Where similarities are denoted either by -1 for invalid, or the
+ * concatenation of the two lines in the diff being compared.
+ *
+ * \param similarities array of similarities between lines in A and B
+ * \param line_a the index of the line in A, in the same frame of reference as
+ * closest_line_a.
+ * \param local_line_b the index of the line in B, relative to the first line
+ * in B that similarities represents.
+ * \param closest_line_a the index of the line in A that is deemed to be
+ * closest to local_line_b. This must be in the same
+ * frame of reference as line_a. This value defines
+ * where similarities is centered for the line in B.
+ * \param max_search_distance_a maximum distance in lines from the closest line
+ * in A for other lines in A for which
+ * similarities may be calculated.
+ */
+static int *get_similarity(int *similarities,
+ int line_a, int local_line_b,
+ int closest_line_a, int max_search_distance_a)
+{
+ assert(abs(line_a - closest_line_a) <=
+ max_search_distance_a);
+ return similarities + line_a - closest_line_a +
+ max_search_distance_a +
+ local_line_b * (max_search_distance_a * 2 + 1);
+}
+
+#define CERTAIN_NOTHING_MATCHES -2
+#define CERTAINTY_NOT_CALCULATED -1
+
+/* Given a line in B, first calculate its similarities with nearby lines in A
+ * if not already calculated, then identify the most similar and second most
+ * similar lines. The "certainty" is calculated based on those two
+ * similarities.
+ *
+ * \param start_a the index of the first line of the chunk in A
+ * \param length_a the length in lines of the chunk in A
+ * \param local_line_b the index of the line in B, relative to the first line
+ * in the chunk.
+ * \param fingerprints_a array of fingerprints for the chunk in A
+ * \param fingerprints_b array of fingerprints for the chunk in B
+ * \param similarities 2-dimensional array of similarities between lines in A
+ * and B. See get_similarity() for more details.
+ * \param certainties array of values indicating how strongly a line in B is
+ * matched with some line in A.
+ * \param second_best_result array of absolute indices in A for the second
+ * closest match of a line in B.
+ * \param result array of absolute indices in A for the closest match of a line
+ * in B.
+ * \param max_search_distance_a maximum distance in lines from the closest line
+ * in A for other lines in A for which
+ * similarities may be calculated.
+ * \param map_line_number_in_b_to_a parameter to map_line_number().
+ */
+static void find_best_line_matches(
+ int start_a,
+ int length_a,
+ int start_b,
+ int local_line_b,
+ struct fingerprint *fingerprints_a,
+ struct fingerprint *fingerprints_b,
+ int *similarities,
+ int *certainties,
+ int *second_best_result,
+ int *result,
+ const int max_search_distance_a,
+ const struct line_number_mapping *map_line_number_in_b_to_a)
+{
+
+ int i, search_start, search_end, closest_local_line_a, *similarity,
+ best_similarity = 0, second_best_similarity = 0,
+ best_similarity_index = 0, second_best_similarity_index = 0;
+
+ /* certainty has already been calculated so no need to redo the work */
+ if (certainties[local_line_b] != CERTAINTY_NOT_CALCULATED)
+ return;
+
+ closest_local_line_a = map_line_number(
+ local_line_b + start_b, map_line_number_in_b_to_a) - start_a;
+
+ search_start = closest_local_line_a - max_search_distance_a;
+ if (search_start < 0)
+ search_start = 0;
+
+ search_end = closest_local_line_a + max_search_distance_a + 1;
+ if (search_end > length_a)
+ search_end = length_a;
+
+ for (i = search_start; i < search_end; ++i) {
+ similarity = get_similarity(similarities,
+ i, local_line_b,
+ closest_local_line_a,
+ max_search_distance_a);
+ if (*similarity == -1) {
+ /* This value will never exceed 10 but assert just in
+ * case
+ */
+ assert(abs(i - closest_local_line_a) < 1000);
+ /* scale the similarity by (1000 - distance from
+ * closest line) to act as a tie break between lines
+ * that otherwise are equally similar.
+ */
+ *similarity = fingerprint_similarity(
+ fingerprints_b + local_line_b,
+ fingerprints_a + i) *
+ (1000 - abs(i - closest_local_line_a));
+ }
+ if (*similarity > best_similarity) {
+ second_best_similarity = best_similarity;
+ second_best_similarity_index = best_similarity_index;
+ best_similarity = *similarity;
+ best_similarity_index = i;
+ } else if (*similarity > second_best_similarity) {
+ second_best_similarity = *similarity;
+ second_best_similarity_index = i;
+ }
+ }
+
+ if (best_similarity == 0) {
+ /* this line definitely doesn't match with anything. Mark it
+ * with this special value so it doesn't get invalidated and
+ * won't be recalculated.
+ */
+ certainties[local_line_b] = CERTAIN_NOTHING_MATCHES;
+ result[local_line_b] = -1;
+ } else {
+ /* Calculate the certainty with which this line matches.
+ * If the line matches well with two lines then that reduces
+ * the certainty. However we still want to prioritise matching
+ * a line that matches very well with two lines over matching a
+ * line that matches poorly with one line, hence doubling
+ * best_similarity.
+ * This means that if we have
+ * line X that matches only one line with a score of 3,
+ * line Y that matches two lines equally with a score of 5,
+ * and line Z that matches only one line with a score or 2,
+ * then the lines in order of certainty are X, Y, Z.
+ */
+ certainties[local_line_b] = best_similarity * 2 -
+ second_best_similarity;
+
+ /* We keep both the best and second best results to allow us to
+ * check at a later stage of the matching process whether the
+ * result needs to be invalidated.
+ */
+ result[local_line_b] = start_a + best_similarity_index;
+ second_best_result[local_line_b] =
+ start_a + second_best_similarity_index;
+ }
+}
+
+/*
+ * This finds the line that we can match with the most confidence, and
+ * uses it as a partition. It then calls itself on the lines on either side of
+ * that partition. In this way we avoid lines appearing out of order, and
+ * retain a sensible line ordering.
+ * \param start_a index of the first line in A with which lines in B may be
+ * compared.
+ * \param start_b index of the first line in B for which matching should be
+ * done.
+ * \param length_a number of lines in A with which lines in B may be compared.
+ * \param length_b number of lines in B for which matching should be done.
+ * \param fingerprints_a mutable array of fingerprints in A. The first element
+ * corresponds to the line at start_a.
+ * \param fingerprints_b array of fingerprints in B. The first element
+ * corresponds to the line at start_b.
+ * \param similarities 2-dimensional array of similarities between lines in A
+ * and B. See get_similarity() for more details.
+ * \param certainties array of values indicating how strongly a line in B is
+ * matched with some line in A.
+ * \param second_best_result array of absolute indices in A for the second
+ * closest match of a line in B.
+ * \param result array of absolute indices in A for the closest match of a line
+ * in B.
+ * \param max_search_distance_a maximum distance in lines from the closest line
+ * in A for other lines in A for which
+ * similarities may be calculated.
+ * \param max_search_distance_b an upper bound on the greatest possible
+ * distance between lines in B such that they will
+ * both be compared with the same line in A
+ * according to max_search_distance_a.
+ * \param map_line_number_in_b_to_a parameter to map_line_number().
+ */
+static void fuzzy_find_matching_lines_recurse(
+ int start_a, int start_b,
+ int length_a, int length_b,
+ struct fingerprint *fingerprints_a,
+ struct fingerprint *fingerprints_b,
+ int *similarities,
+ int *certainties,
+ int *second_best_result,
+ int *result,
+ int max_search_distance_a,
+ int max_search_distance_b,
+ const struct line_number_mapping *map_line_number_in_b_to_a)
+{
+ int i, invalidate_min, invalidate_max, offset_b,
+ second_half_start_a, second_half_start_b,
+ second_half_length_a, second_half_length_b,
+ most_certain_line_a, most_certain_local_line_b = -1,
+ most_certain_line_certainty = -1,
+ closest_local_line_a;
+
+ for (i = 0; i < length_b; ++i) {
+ find_best_line_matches(start_a,
+ length_a,
+ start_b,
+ i,
+ fingerprints_a,
+ fingerprints_b,
+ similarities,
+ certainties,
+ second_best_result,
+ result,
+ max_search_distance_a,
+ map_line_number_in_b_to_a);
+
+ if (certainties[i] > most_certain_line_certainty) {
+ most_certain_line_certainty = certainties[i];
+ most_certain_local_line_b = i;
+ }
+ }
+
+ /* No matches. */
+ if (most_certain_local_line_b == -1)
+ return;
+
+ most_certain_line_a = result[most_certain_local_line_b];
+
+ /*
+ * Subtract the most certain line's fingerprint in B from the matched
+ * fingerprint in A. This means that other lines in B can't also match
+ * the same parts of the line in A.
+ */
+ fingerprint_subtract(fingerprints_a + most_certain_line_a - start_a,
+ fingerprints_b + most_certain_local_line_b);
+
+ /* Invalidate results that may be affected by the choice of most
+ * certain line.
+ */
+ invalidate_min = most_certain_local_line_b - max_search_distance_b;
+ invalidate_max = most_certain_local_line_b + max_search_distance_b + 1;
+ if (invalidate_min < 0)
+ invalidate_min = 0;
+ if (invalidate_max > length_b)
+ invalidate_max = length_b;
+
+ /* As the fingerprint in A has changed, discard previously calculated
+ * similarity values with that fingerprint.
+ */
+ for (i = invalidate_min; i < invalidate_max; ++i) {
+ closest_local_line_a = map_line_number(
+ i + start_b, map_line_number_in_b_to_a) - start_a;
+
+ /* Check that the lines in A and B are close enough that there
+ * is a similarity value for them.
+ */
+ if (abs(most_certain_line_a - start_a - closest_local_line_a) >
+ max_search_distance_a) {
+ continue;
+ }
+
+ *get_similarity(similarities, most_certain_line_a - start_a,
+ i, closest_local_line_a,
+ max_search_distance_a) = -1;
+ }
+
+ /* More invalidating of results that may be affected by the choice of
+ * most certain line.
+ * Discard the matches for lines in B that are currently matched with a
+ * line in A such that their ordering contradicts the ordering imposed
+ * by the choice of most certain line.
+ */
+ for (i = most_certain_local_line_b - 1; i >= invalidate_min; --i) {
+ /* In this loop we discard results for lines in B that are
+ * before most-certain-line-B but are matched with a line in A
+ * that is after most-certain-line-A.
+ */
+ if (certainties[i] >= 0 &&
+ (result[i] >= most_certain_line_a ||
+ second_best_result[i] >= most_certain_line_a)) {
+ certainties[i] = CERTAINTY_NOT_CALCULATED;
+ }
+ }
+ for (i = most_certain_local_line_b + 1; i < invalidate_max; ++i) {
+ /* In this loop we discard results for lines in B that are
+ * after most-certain-line-B but are matched with a line in A
+ * that is before most-certain-line-A.
+ */
+ if (certainties[i] >= 0 &&
+ (result[i] <= most_certain_line_a ||
+ second_best_result[i] <= most_certain_line_a)) {
+ certainties[i] = CERTAINTY_NOT_CALCULATED;
+ }
+ }
+
+ /* Repeat the matching process for lines before the most certain line.
+ */
+ if (most_certain_local_line_b > 0) {
+ fuzzy_find_matching_lines_recurse(
+ start_a, start_b,
+ most_certain_line_a + 1 - start_a,
+ most_certain_local_line_b,
+ fingerprints_a, fingerprints_b, similarities,
+ certainties, second_best_result, result,
+ max_search_distance_a,
+ max_search_distance_b,
+ map_line_number_in_b_to_a);
+ }
+ /* Repeat the matching process for lines after the most certain line.
+ */
+ if (most_certain_local_line_b + 1 < length_b) {
+ second_half_start_a = most_certain_line_a;
+ offset_b = most_certain_local_line_b + 1;
+ second_half_start_b = start_b + offset_b;
+ second_half_length_a =
+ length_a + start_a - second_half_start_a;
+ second_half_length_b =
+ length_b + start_b - second_half_start_b;
+ fuzzy_find_matching_lines_recurse(
+ second_half_start_a, second_half_start_b,
+ second_half_length_a, second_half_length_b,
+ fingerprints_a + second_half_start_a - start_a,
+ fingerprints_b + offset_b,
+ similarities +
+ offset_b * (max_search_distance_a * 2 + 1),
+ certainties + offset_b,
+ second_best_result + offset_b, result + offset_b,
+ max_search_distance_a,
+ max_search_distance_b,
+ map_line_number_in_b_to_a);
+ }
+}
+
+/* Find the lines in the parent line range that most closely match the lines in
+ * the target line range. This is accomplished by matching fingerprints in each
+ * blame_origin, and choosing the best matches that preserve the line ordering.
+ * See struct fingerprint for details of fingerprint matching, and
+ * fuzzy_find_matching_lines_recurse for details of preserving line ordering.
+ *
+ * The performance is believed to be O(n log n) in the typical case and O(n^2)
+ * in a pathological case, where n is the number of lines in the target range.
+ */
+static int *fuzzy_find_matching_lines(struct blame_origin *parent,
+ struct blame_origin *target,
+ int tlno, int parent_slno, int same,
+ int parent_len)
+{
+ /* We use the terminology "A" for the left hand side of the diff AKA
+ * parent, and "B" for the right hand side of the diff AKA target. */
+ int start_a = parent_slno;
+ int length_a = parent_len;
+ int start_b = tlno;
+ int length_b = same - tlno;
+
+ struct line_number_mapping map_line_number_in_b_to_a = {
+ start_a, length_a, start_b, length_b
+ };
+
+ struct fingerprint *fingerprints_a = parent->fingerprints;
+ struct fingerprint *fingerprints_b = target->fingerprints;
+
+ int i, *result, *second_best_result,
+ *certainties, *similarities, similarity_count;
+
+ /*
+ * max_search_distance_a means that given a line in B, compare it to
+ * the line in A that is closest to its position, and the lines in A
+ * that are no greater than max_search_distance_a lines away from the
+ * closest line in A.
+ *
+ * max_search_distance_b is an upper bound on the greatest possible
+ * distance between lines in B such that they will both be compared
+ * with the same line in A according to max_search_distance_a.
+ */
+ int max_search_distance_a = 10, max_search_distance_b;
+
+ if (length_a <= 0)
+ return NULL;
+
+ if (max_search_distance_a >= length_a)
+ max_search_distance_a = length_a ? length_a - 1 : 0;
+
+ max_search_distance_b = ((2 * max_search_distance_a + 1) * length_b
+ - 1) / length_a;
+
+ CALLOC_ARRAY(result, length_b);
+ CALLOC_ARRAY(second_best_result, length_b);
+ CALLOC_ARRAY(certainties, length_b);
+
+ /* See get_similarity() for details of similarities. */
+ similarity_count = length_b * (max_search_distance_a * 2 + 1);
+ CALLOC_ARRAY(similarities, similarity_count);
+
+ for (i = 0; i < length_b; ++i) {
+ result[i] = -1;
+ second_best_result[i] = -1;
+ certainties[i] = CERTAINTY_NOT_CALCULATED;
+ }
+
+ for (i = 0; i < similarity_count; ++i)
+ similarities[i] = -1;
+
+ fuzzy_find_matching_lines_recurse(start_a, start_b,
+ length_a, length_b,
+ fingerprints_a + start_a,
+ fingerprints_b + start_b,
+ similarities,
+ certainties,
+ second_best_result,
+ result,
+ max_search_distance_a,
+ max_search_distance_b,
+ &map_line_number_in_b_to_a);
+
+ free(similarities);
+ free(certainties);
+ free(second_best_result);
+
+ return result;
+}
+
+static void fill_origin_fingerprints(struct blame_origin *o)
+{
+ int *line_starts;
+
+ if (o->fingerprints)
+ return;
+ o->num_lines = find_line_starts(&line_starts, o->file.ptr,
+ o->file.size);
+ CALLOC_ARRAY(o->fingerprints, o->num_lines);
+ get_line_fingerprints(o->fingerprints, o->file.ptr, line_starts,
+ 0, o->num_lines);
+ free(line_starts);
+}
+
+static void drop_origin_fingerprints(struct blame_origin *o)
+{
+ if (o->fingerprints) {
+ free_line_fingerprints(o->fingerprints, o->num_lines);
+ o->num_lines = 0;
+ FREE_AND_NULL(o->fingerprints);
+ }
+}
+
+/*
+ * 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, int fill_fingerprints)
+{
+ 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;
+ if (fill_fingerprints)
+ fill_origin_fingerprints(o);
+}
+
+static void drop_origin_blob(struct blame_origin *o)
+{
+ FREE_AND_NULL(o->file.ptr);
+ drop_origin_fingerprints(o);
+}
+
+/*
+ * 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)) {
+ *tail = p2;
+ return list1;
+ }
+ } while (p1->s_lno <= p2->s_lno);
+ }
+ for (;;) {
+ *tail = p2;
+ do {
+ tail = &p2->next;
+ if (!(p2 = *tail)) {
+ *tail = p1;
+ return list1;
+ }
+ } while (p1->s_lno > p2->s_lno);
+ *tail = p1;
+ do {
+ tail = &p1->next;
+ if (!(p1 = *tail)) {
+ *tail = p2;
+ return list1;
+ }
+ } while (p1->s_lno <= p2->s_lno);
+ }
+}
+
+DEFINE_LIST_SORT(static, sort_blame_entries, struct blame_entry, next);
+
+/*
+ * Final image line numbers are all different, so we don't need a
+ * three-way comparison here.
+ */
+
+static int compare_blame_final(const struct blame_entry *e1,
+ const struct blame_entry *e2)
+{
+ return e1->lno > e2->lno ? 1 : -1;
+}
+
+static int compare_blame_suspect(const struct blame_entry *s1,
+ const struct blame_entry *s2)
+{
+ /*
+ * 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)
+{
+ sort_blame_entries(&sb->ent, 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->lno + ent->num_lines == next->lno &&
+ ent->ignored == next->ignored &&
+ ent->unblamable == next->unblamable) {
+ 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(r, &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;
+}
+
+struct blame_bloom_data {
+ /*
+ * Changed-path Bloom filter keys. These can help prevent
+ * computing diffs against first parents, but we need to
+ * expand the list as code is moved or files are renamed.
+ */
+ struct bloom_filter_settings *settings;
+ struct bloom_key **keys;
+ int nr;
+ int alloc;
+};
+
+static int bloom_count_queries = 0;
+static int bloom_count_no = 0;
+static int maybe_changed_path(struct repository *r,
+ struct blame_origin *origin,
+ struct blame_bloom_data *bd)
+{
+ int i;
+ struct bloom_filter *filter;
+
+ if (!bd)
+ return 1;
+
+ if (commit_graph_generation(origin->commit) == GENERATION_NUMBER_INFINITY)
+ return 1;
+
+ filter = get_bloom_filter(r, origin->commit);
+
+ if (!filter)
+ return 1;
+
+ bloom_count_queries++;
+ for (i = 0; i < bd->nr; i++) {
+ if (bloom_filter_contains(filter,
+ bd->keys[i],
+ bd->settings))
+ return 1;
+ }
+
+ bloom_count_no++;
+ return 0;
+}
+
+static void add_bloom_key(struct blame_bloom_data *bd,
+ const char *path)
+{
+ if (!bd)
+ return;
+
+ if (bd->nr >= bd->alloc) {
+ bd->alloc *= 2;
+ REALLOC_ARRAY(bd->keys, bd->alloc);
+ }
+
+ bd->keys[bd->nr] = xmalloc(sizeof(struct bloom_key));
+ fill_bloom_key(path, strlen(path), bd->keys[bd->nr], bd->settings);
+ bd->nr++;
+}
+
+/*
+ * 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_bloom_data *bd)
+{
+ 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 {
+ int compute_diff = 1;
+ if (origin->commit->parents &&
+ oideq(&parent->object.oid,
+ &origin->commit->parents->item->object.oid))
+ compute_diff = maybe_changed_path(r, origin, bd);
+
+ if (compute_diff)
+ 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);
+ 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_bloom_data *bd)
+{
+ 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)) {
+ add_bloom_key(bd, p->one->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);
+ 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;
+ int i;
+ memset(split, 0, sizeof(struct blame_entry [3]));
+
+ for (i = 0; i < 3; i++) {
+ split[i].ignored = e->ignored;
+ split[i].unblamable = e->unblamable;
+ }
+
+ 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;
+}
+
+/*
+ * Splits a blame entry into two entries at 'len' lines. The original 'e'
+ * consists of len lines, i.e. [e->lno, e->lno + len), and the second part,
+ * which is returned, consists of the remainder: [e->lno + len, e->lno +
+ * e->num_lines). The caller needs to sort out the reference counting for the
+ * new entry's suspect.
+ */
+static struct blame_entry *split_blame_at(struct blame_entry *e, int len,
+ struct blame_origin *new_suspect)
+{
+ struct blame_entry *n = xcalloc(1, sizeof(struct blame_entry));
+
+ n->suspect = new_suspect;
+ n->ignored = e->ignored;
+ n->unblamable = e->unblamable;
+ 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;
+ return n;
+}
+
+struct blame_line_tracker {
+ int is_parent;
+ int s_lno;
+};
+
+static int are_lines_adjacent(struct blame_line_tracker *first,
+ struct blame_line_tracker *second)
+{
+ return first->is_parent == second->is_parent &&
+ first->s_lno + 1 == second->s_lno;
+}
+
+static int scan_parent_range(struct fingerprint *p_fps,
+ struct fingerprint *t_fps, int t_idx,
+ int from, int nr_lines)
+{
+ int sim, p_idx;
+ #define FINGERPRINT_FILE_THRESHOLD 10
+ int best_sim_val = FINGERPRINT_FILE_THRESHOLD;
+ int best_sim_idx = -1;
+
+ for (p_idx = from; p_idx < from + nr_lines; p_idx++) {
+ sim = fingerprint_similarity(&t_fps[t_idx], &p_fps[p_idx]);
+ if (sim < best_sim_val)
+ continue;
+ /* Break ties with the closest-to-target line number */
+ if (sim == best_sim_val && best_sim_idx != -1 &&
+ abs(best_sim_idx - t_idx) < abs(p_idx - t_idx))
+ continue;
+ best_sim_val = sim;
+ best_sim_idx = p_idx;
+ }
+ return best_sim_idx;
+}
+
+/*
+ * The first pass checks the blame entry (from the target) against the parent's
+ * diff chunk. If that fails for a line, the second pass tries to match that
+ * line to any part of parent file. That catches cases where a change was
+ * broken into two chunks by 'context.'
+ */
+static void guess_line_blames(struct blame_origin *parent,
+ struct blame_origin *target,
+ int tlno, int offset, int same, int parent_len,
+ struct blame_line_tracker *line_blames)
+{
+ int i, best_idx, target_idx;
+ int parent_slno = tlno + offset;
+ int *fuzzy_matches;
+
+ fuzzy_matches = fuzzy_find_matching_lines(parent, target,
+ tlno, parent_slno, same,
+ parent_len);
+ for (i = 0; i < same - tlno; i++) {
+ target_idx = tlno + i;
+ if (fuzzy_matches && fuzzy_matches[i] >= 0) {
+ best_idx = fuzzy_matches[i];
+ } else {
+ best_idx = scan_parent_range(parent->fingerprints,
+ target->fingerprints,
+ target_idx, 0,
+ parent->num_lines);
+ }
+ if (best_idx >= 0) {
+ line_blames[i].is_parent = 1;
+ line_blames[i].s_lno = best_idx;
+ } else {
+ line_blames[i].is_parent = 0;
+ line_blames[i].s_lno = target_idx;
+ }
+ }
+ free(fuzzy_matches);
+}
+
+/*
+ * This decides which parts of a blame entry go to the parent (added to the
+ * ignoredp list) and which stay with the target (added to the diffp list). The
+ * actual decision was made in a separate heuristic function, and those answers
+ * for the lines in 'e' are in line_blames. This consumes e, essentially
+ * putting it on a list.
+ *
+ * Note that the blame entries on the ignoredp list are not necessarily sorted
+ * with respect to the parent's line numbers yet.
+ */
+static void ignore_blame_entry(struct blame_entry *e,
+ struct blame_origin *parent,
+ struct blame_entry **diffp,
+ struct blame_entry **ignoredp,
+ struct blame_line_tracker *line_blames)
+{
+ int entry_len, nr_lines, i;
+
+ /*
+ * We carve new entries off the front of e. Each entry comes from a
+ * contiguous chunk of lines: adjacent lines from the same origin
+ * (either the parent or the target).
+ */
+ entry_len = 1;
+ nr_lines = e->num_lines; /* e changes in the loop */
+ for (i = 0; i < nr_lines; i++) {
+ struct blame_entry *next = NULL;
+
+ /*
+ * We are often adjacent to the next line - only split the blame
+ * entry when we have to.
+ */
+ if (i + 1 < nr_lines) {
+ if (are_lines_adjacent(&line_blames[i],
+ &line_blames[i + 1])) {
+ entry_len++;
+ continue;
+ }
+ next = split_blame_at(e, entry_len,
+ blame_origin_incref(e->suspect));
+ }
+ if (line_blames[i].is_parent) {
+ e->ignored = 1;
+ blame_origin_decref(e->suspect);
+ e->suspect = blame_origin_incref(parent);
+ e->s_lno = line_blames[i - entry_len + 1].s_lno;
+ e->next = *ignoredp;
+ *ignoredp = e;
+ } else {
+ e->unblamable = 1;
+ /* e->s_lno is already in the target's address space. */
+ e->next = *diffp;
+ *diffp = e;
+ }
+ assert(e->num_lines == entry_len);
+ e = next;
+ entry_len = 1;
+ }
+ assert(!e);
+}
+
+/*
+ * 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.
+ *
+ * tlno: line number in the target where this chunk begins
+ * same: line number in the target where this chunk ends
+ * offset: add to tlno to get the chunk starting point in the parent
+ * parent_len: number of lines in the parent chunk
+ */
+static void blame_chunk(struct blame_entry ***dstq, struct blame_entry ***srcq,
+ int tlno, int offset, int same, int parent_len,
+ struct blame_origin *parent,
+ struct blame_origin *target, int ignore_diffs)
+{
+ struct blame_entry *e = **srcq;
+ struct blame_entry *samep = NULL, *diffp = NULL, *ignoredp = NULL;
+ struct blame_line_tracker *line_blames = 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 */
+ struct blame_entry *n;
+
+ n = split_blame_at(e, tlno - e->s_lno, e->suspect);
+ /* 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;
+
+ if (ignore_diffs && same - tlno > 0) {
+ CALLOC_ARRAY(line_blames, same - tlno);
+ guess_line_blames(parent, target, tlno, offset, same,
+ parent_len, line_blames);
+ }
+
+ 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
+ */
+ struct blame_entry *n;
+
+ n = split_blame_at(e, same - e->s_lno,
+ blame_origin_incref(e->suspect));
+ /* Push new record to samep */
+ n->next = samep;
+ samep = n;
+ }
+ if (ignore_diffs) {
+ ignore_blame_entry(e, parent, &diffp, &ignoredp,
+ line_blames + e->s_lno - tlno);
+ } else {
+ e->next = diffp;
+ diffp = e;
+ }
+ e = next;
+ }
+ free(line_blames);
+ if (ignoredp) {
+ /*
+ * Note ignoredp is not sorted yet, and thus neither is dstq.
+ * That list must be sorted before we queue_blames(). We defer
+ * sorting until after all diff hunks are processed, so that
+ * guess_line_blames() can pick *any* line in the parent. The
+ * slight drawback is that we end up sorting all blame entries
+ * passed to the parent, including those that are unrelated to
+ * changes made by the ignored commit.
+ */
+ **dstq = reverse_blame(ignoredp, **dstq);
+ *dstq = &ignoredp->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;
+ struct blame_origin *target;
+ long offset;
+ int ignore_diffs;
+ 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, count_a, d->parent, d->target,
+ d->ignore_diffs);
+ 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, int ignore_diffs)
+{
+ 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.target = target;
+ d.offset = 0;
+ d.ignore_diffs = ignore_diffs;
+ d.dstq = &newdest; d.srcq = &target->suspects;
+
+ fill_origin_blob(&sb->revs->diffopt, parent, &file_p,
+ &sb->num_read_blob, ignore_diffs);
+ fill_origin_blob(&sb->revs->diffopt, target, &file_o,
+ &sb->num_read_blob, ignore_diffs);
+ 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, 0,
+ parent, target, 0);
+ *d.dstq = NULL;
+ if (ignore_diffs)
+ sort_blame_entries(&newdest, compare_blame_suspect);
+ 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, 0);
+ 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) {
+ CALLOC_ARRAY(blame_list, num_ents);
+ 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, 0);
+ 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);
+}
+
+/*
+ * 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)
+{
+ sort_blame_entries(&blamed, 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
+
+typedef struct blame_origin *(*blame_find_alg)(struct repository *,
+ struct commit *,
+ struct blame_origin *,
+ struct blame_bloom_data *);
+
+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
+ CALLOC_ARRAY(sg_origin, num_sg);
+
+ /*
+ * 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++) {
+ blame_find_alg 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, sb->bloom_data);
+ 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, 0);
+ if (!origin->suspects)
+ goto finish;
+ }
+
+ /*
+ * Pass remaining suspects for ignored commits to their parents.
+ */
+ if (oidset_contains(&sb->ignore_list, &commit->object.oid)) {
+ 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;
+ pass_blame_to_parent(sb, origin, porigin, 1);
+ /*
+ * Preemptively drop porigin so we can refresh the
+ * fingerprints if we use the parent again, which can
+ * occur if you ignore back-to-back commits.
+ */
+ drop_origin_blob(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]) {
+ if (!sg_origin[i]->suspects)
+ 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(sb->revs, 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);
+ }
+}
+
+/*
+ * 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)
+{
+ sb->num_lines = find_line_starts(&sb->lineno, sb->final_buf,
+ sb->final_buf_size);
+ 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 || 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 || 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 || 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,
+ 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,
+ sb->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, sb->path);
+ if (fill_blob_sha1_and_mode(sb->repo, o))
+ die(_("no such path %s in %s"), sb->path, final_commit_name);
+
+ if (sb->revs->diffopt.flags.allow_textconv &&
+ textconv_object(sb->repo, sb->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),
+ sb->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;
+}
+
+void setup_blame_bloom_data(struct blame_scoreboard *sb)
+{
+ struct blame_bloom_data *bd;
+ struct bloom_filter_settings *bs;
+
+ if (!sb->repo->objects->commit_graph)
+ return;
+
+ bs = get_bloom_filter_settings(sb->repo);
+ if (!bs)
+ return;
+
+ bd = xmalloc(sizeof(struct blame_bloom_data));
+
+ bd->settings = bs;
+
+ bd->alloc = 4;
+ bd->nr = 0;
+ ALLOC_ARRAY(bd->keys, bd->alloc);
+
+ add_bloom_key(bd, sb->path);
+
+ sb->bloom_data = bd;
+}
+
+void cleanup_scoreboard(struct blame_scoreboard *sb)
+{
+ if (sb->bloom_data) {
+ int i;
+ for (i = 0; i < sb->bloom_data->nr; i++) {
+ free(sb->bloom_data->keys[i]->hashes);
+ free(sb->bloom_data->keys[i]);
+ }
+ free(sb->bloom_data->keys);
+ FREE_AND_NULL(sb->bloom_data);
+
+ trace2_data_intmax("blame", sb->repo,
+ "bloom/queries", bloom_count_queries);
+ trace2_data_intmax("blame", sb->repo,
+ "bloom/response-no", bloom_count_no);
+ }
+}