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Diffstat (limited to 'builtin/blame.c')
| -rw-r--r-- | builtin/blame.c | 2477 |
1 files changed, 2477 insertions, 0 deletions
diff --git a/builtin/blame.c b/builtin/blame.c new file mode 100644 index 0000000000..8506286dd2 --- /dev/null +++ b/builtin/blame.c @@ -0,0 +1,2477 @@ +/* + * Blame + * + * Copyright (c) 2006, Junio C Hamano + */ + +#include "cache.h" +#include "builtin.h" +#include "blob.h" +#include "commit.h" +#include "tag.h" +#include "tree-walk.h" +#include "diff.h" +#include "diffcore.h" +#include "revision.h" +#include "quote.h" +#include "xdiff-interface.h" +#include "cache-tree.h" +#include "string-list.h" +#include "mailmap.h" +#include "parse-options.h" +#include "utf8.h" + +static char blame_usage[] = "git blame [options] [rev-opts] [rev] [--] file"; + +static const char *blame_opt_usage[] = { + blame_usage, + "", + "[rev-opts] are documented in git-rev-list(1)", + NULL +}; + +static int longest_file; +static int longest_author; +static int max_orig_digits; +static int max_digits; +static int max_score_digits; +static int show_root; +static int reverse; +static int blank_boundary; +static int incremental; +static int xdl_opts; + +static enum date_mode blame_date_mode = DATE_ISO8601; +static size_t blame_date_width; + +static struct string_list mailmap; + +#ifndef DEBUG +#define DEBUG 0 +#endif + +/* stats */ +static int num_read_blob; +static int num_get_patch; +static int num_commits; + +#define PICKAXE_BLAME_MOVE 01 +#define PICKAXE_BLAME_COPY 02 +#define PICKAXE_BLAME_COPY_HARDER 04 +#define PICKAXE_BLAME_COPY_HARDEST 010 + +/* + * blame for a blame_entry with score lower than these thresholds + * is not passed to the parent using move/copy logic. + */ +static unsigned blame_move_score; +static unsigned blame_copy_score; +#define BLAME_DEFAULT_MOVE_SCORE 20 +#define BLAME_DEFAULT_COPY_SCORE 40 + +/* bits #0..7 in revision.h, #8..11 used for merge_bases() in commit.c */ +#define METAINFO_SHOWN (1u<<12) +#define MORE_THAN_ONE_PATH (1u<<13) + +/* + * One blob in a commit that is being suspected + */ +struct origin { + int refcnt; + struct origin *previous; + struct commit *commit; + mmfile_t file; + unsigned char blob_sha1[20]; + char path[FLEX_ARRAY]; +}; + +/* + * Given an origin, prepare mmfile_t structure to be used by the + * diff machinery + */ +static void fill_origin_blob(struct origin *o, mmfile_t *file) +{ + if (!o->file.ptr) { + enum object_type type; + num_read_blob++; + file->ptr = read_sha1_file(o->blob_sha1, &type, + (unsigned long *)(&(file->size))); + if (!file->ptr) + die("Cannot read blob %s for path %s", + sha1_to_hex(o->blob_sha1), + o->path); + o->file = *file; + } + else + *file = o->file; +} + +/* + * Origin is refcounted and usually we keep the blob contents to be + * reused. + */ +static inline struct origin *origin_incref(struct origin *o) +{ + if (o) + o->refcnt++; + return o; +} + +static void origin_decref(struct origin *o) +{ + if (o && --o->refcnt <= 0) { + if (o->previous) + origin_decref(o->previous); + free(o->file.ptr); + free(o); + } +} + +static void drop_origin_blob(struct origin *o) +{ + if (o->file.ptr) { + free(o->file.ptr); + o->file.ptr = NULL; + } +} + +/* + * Each group of lines is described by a blame_entry; it can be split + * as we pass blame to the parents. They form a linked list in the + * scoreboard structure, sorted by the target line number. + */ +struct blame_entry { + struct blame_entry *prev; + struct blame_entry *next; + + /* the first line of this group in the final image; + * internally all line numbers are 0 based. + */ + int lno; + + /* how many lines this group has */ + int num_lines; + + /* the commit that introduced this group into the final image */ + struct origin *suspect; + + /* true if the suspect is truly guilty; false while we have not + * checked if the group came from one of its parents. + */ + char guilty; + + /* true if the entry has been scanned for copies in the current parent + */ + char scanned; + + /* the line number of the first line of this group in the + * suspect's file; internally all line numbers are 0 based. + */ + int s_lno; + + /* how significant this entry is -- cached to avoid + * scanning the lines over and over. + */ + unsigned score; +}; + +/* + * The current state of the blame assignment. + */ +struct scoreboard { + /* the final commit (i.e. where we started digging from) */ + struct commit *final; + struct rev_info *revs; + const char *path; + + /* + * The contents in the final image. + * Used by many functions to obtain contents of the nth line, + * indexed with scoreboard.lineno[blame_entry.lno]. + */ + const char *final_buf; + unsigned long final_buf_size; + + /* linked list of blames */ + struct blame_entry *ent; + + /* look-up a line in the final buffer */ + int num_lines; + int *lineno; +}; + +static inline int same_suspect(struct origin *a, struct origin *b) +{ + if (a == b) + return 1; + if (a->commit != b->commit) + return 0; + return !strcmp(a->path, b->path); +} + +static void sanity_check_refcnt(struct scoreboard *); + +/* + * 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. + */ +static void coalesce(struct scoreboard *sb) +{ + struct blame_entry *ent, *next; + + for (ent = sb->ent; ent && (next = ent->next); ent = next) { + if (same_suspect(ent->suspect, next->suspect) && + ent->guilty == next->guilty && + ent->s_lno + ent->num_lines == next->s_lno) { + ent->num_lines += next->num_lines; + ent->next = next->next; + if (ent->next) + ent->next->prev = ent; + origin_decref(next->suspect); + free(next); + ent->score = 0; + next = ent; /* again */ + } + } + + if (DEBUG) /* sanity */ + sanity_check_refcnt(sb); +} + +/* + * 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 origin *make_origin(struct commit *commit, const char *path) +{ + struct origin *o; + o = xcalloc(1, sizeof(*o) + strlen(path) + 1); + o->commit = commit; + o->refcnt = 1; + strcpy(o->path, path); + return o; +} + +/* + * Locate an existing origin or create a new one. + */ +static struct origin *get_origin(struct scoreboard *sb, + struct commit *commit, + const char *path) +{ + struct blame_entry *e; + + for (e = sb->ent; e; e = e->next) { + if (e->suspect->commit == commit && + !strcmp(e->suspect->path, path)) + return origin_incref(e->suspect); + } + return make_origin(commit, path); +} + +/* + * 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. + */ +static int fill_blob_sha1(struct origin *origin) +{ + unsigned mode; + + if (!is_null_sha1(origin->blob_sha1)) + return 0; + if (get_tree_entry(origin->commit->object.sha1, + origin->path, + origin->blob_sha1, &mode)) + goto error_out; + if (sha1_object_info(origin->blob_sha1, NULL) != OBJ_BLOB) + goto error_out; + return 0; + error_out: + hashclr(origin->blob_sha1); + 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 origin *find_origin(struct scoreboard *sb, + struct commit *parent, + struct origin *origin) +{ + struct origin *porigin = NULL; + struct diff_options diff_opts; + const char *paths[2]; + + if (parent->util) { + /* + * Each commit object can cache one origin in that + * commit. This is a freestanding copy of origin and + * not refcounted. + */ + struct origin *cached = parent->util; + if (!strcmp(cached->path, origin->path)) { + /* + * The same path between origin and its parent + * without renaming -- the most common case. + */ + porigin = get_origin(sb, parent, cached->path); + + /* + * If the origin was newly created (i.e. get_origin + * would call make_origin if none is found in the + * scoreboard), it does not know the blob_sha1, + * so copy it. Otherwise porigin was in the + * scoreboard and already knows blob_sha1. + */ + if (porigin->refcnt == 1) + hashcpy(porigin->blob_sha1, cached->blob_sha1); + return porigin; + } + /* otherwise it was not very useful; free it */ + free(parent->util); + parent->util = NULL; + } + + /* 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. + */ + diff_setup(&diff_opts); + DIFF_OPT_SET(&diff_opts, RECURSIVE); + diff_opts.detect_rename = 0; + diff_opts.output_format = DIFF_FORMAT_NO_OUTPUT; + paths[0] = origin->path; + paths[1] = NULL; + + diff_tree_setup_paths(paths, &diff_opts); + if (diff_setup_done(&diff_opts) < 0) + die("diff-setup"); + + if (is_null_sha1(origin->commit->object.sha1)) + do_diff_cache(parent->tree->object.sha1, &diff_opts); + else + diff_tree_sha1(parent->tree->object.sha1, + origin->commit->tree->object.sha1, + "", &diff_opts); + diffcore_std(&diff_opts); + + if (!diff_queued_diff.nr) { + /* The path is the same as parent */ + porigin = get_origin(sb, parent, origin->path); + hashcpy(porigin->blob_sha1, origin->blob_sha1); + } 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(sb, parent, origin->path); + hashcpy(porigin->blob_sha1, p->one->sha1); + break; + case 'A': + case 'T': + /* Did not exist in parent, or type changed */ + break; + } + } + diff_flush(&diff_opts); + diff_tree_release_paths(&diff_opts); + if (porigin) { + /* + * Create a freestanding copy that is not part of + * the refcounted origin found in the scoreboard, and + * cache it in the commit. + */ + struct origin *cached; + + cached = make_origin(porigin->commit, porigin->path); + hashcpy(cached->blob_sha1, porigin->blob_sha1); + parent->util = cached; + } + 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 origin *find_rename(struct scoreboard *sb, + struct commit *parent, + struct origin *origin) +{ + struct origin *porigin = NULL; + struct diff_options diff_opts; + int i; + const char *paths[2]; + + diff_setup(&diff_opts); + DIFF_OPT_SET(&diff_opts, RECURSIVE); + diff_opts.detect_rename = DIFF_DETECT_RENAME; + diff_opts.output_format = DIFF_FORMAT_NO_OUTPUT; + diff_opts.single_follow = origin->path; + paths[0] = NULL; + diff_tree_setup_paths(paths, &diff_opts); + if (diff_setup_done(&diff_opts) < 0) + die("diff-setup"); + + if (is_null_sha1(origin->commit->object.sha1)) + do_diff_cache(parent->tree->object.sha1, &diff_opts); + else + diff_tree_sha1(parent->tree->object.sha1, + origin->commit->tree->object.sha1, + "", &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(sb, parent, p->one->path); + hashcpy(porigin->blob_sha1, p->one->sha1); + break; + } + } + diff_flush(&diff_opts); + diff_tree_release_paths(&diff_opts); + return porigin; +} + +/* + * Link in a new blame entry to the scoreboard. Entries that cover the + * same line range have been removed from the scoreboard previously. + */ +static void add_blame_entry(struct scoreboard *sb, struct blame_entry *e) +{ + struct blame_entry *ent, *prev = NULL; + + origin_incref(e->suspect); + + for (ent = sb->ent; ent && ent->lno < e->lno; ent = ent->next) + prev = ent; + + /* prev, if not NULL, is the last one that is below e */ + e->prev = prev; + if (prev) { + e->next = prev->next; + prev->next = e; + } + else { + e->next = sb->ent; + sb->ent = e; + } + if (e->next) + e->next->prev = e; +} + +/* + * src typically is on-stack; we want to copy the information in it to + * a malloced blame_entry that is already on the linked list of the + * scoreboard. The origin of dst loses a refcnt while the origin of src + * gains one. + */ +static void dup_entry(struct blame_entry *dst, struct blame_entry *src) +{ + struct blame_entry *p, *n; + + p = dst->prev; + n = dst->next; + origin_incref(src->suspect); + origin_decref(dst->suspect); + memcpy(dst, src, sizeof(*src)); + dst->prev = p; + dst->next = n; + dst->score = 0; +} + +static const char *nth_line(struct scoreboard *sb, int 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 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 = 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 = 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 = origin_incref(parent); +} + +/* + * split_overlap() divided an existing blame e into up to three parts + * in split. Adjust the linked list of blames in the scoreboard to + * reflect the split. + */ +static void split_blame(struct scoreboard *sb, + struct blame_entry *split, + struct blame_entry *e) +{ + struct blame_entry *new_entry; + + if (split[0].suspect && split[2].suspect) { + /* The first part (reuse storage for the existing entry e) */ + dup_entry(e, &split[0]); + + /* The last part -- me */ + new_entry = xmalloc(sizeof(*new_entry)); + memcpy(new_entry, &(split[2]), sizeof(struct blame_entry)); + add_blame_entry(sb, new_entry); + + /* ... and the middle part -- parent */ + new_entry = xmalloc(sizeof(*new_entry)); + memcpy(new_entry, &(split[1]), sizeof(struct blame_entry)); + add_blame_entry(sb, new_entry); + } + 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(e, &split[1]); + else if (split[0].suspect) { + /* me and then parent */ + dup_entry(e, &split[0]); + + new_entry = xmalloc(sizeof(*new_entry)); + memcpy(new_entry, &(split[1]), sizeof(struct blame_entry)); + add_blame_entry(sb, new_entry); + } + else { + /* parent and then me */ + dup_entry(e, &split[1]); + + new_entry = xmalloc(sizeof(*new_entry)); + memcpy(new_entry, &(split[2]), sizeof(struct blame_entry)); + add_blame_entry(sb, new_entry); + } + + if (DEBUG) { /* sanity */ + struct blame_entry *ent; + int lno = sb->ent->lno, corrupt = 0; + + for (ent = sb->ent; ent; ent = ent->next) { + if (lno != ent->lno) + corrupt = 1; + if (ent->s_lno < 0) + corrupt = 1; + lno += ent->num_lines; + } + if (corrupt) { + lno = sb->ent->lno; + for (ent = sb->ent; ent; ent = ent->next) { + printf("L %8d l %8d n %8d\n", + lno, ent->lno, ent->num_lines); + lno = ent->lno + ent->num_lines; + } + die("oops"); + } + } +} + +/* + * 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++) + origin_decref(split[i].suspect); +} + +/* + * Helper for blame_chunk(). blame_entry e is known to overlap with + * the patch hunk; split it and pass blame to the parent. + */ +static void blame_overlap(struct scoreboard *sb, struct blame_entry *e, + int tlno, int plno, int same, + struct origin *parent) +{ + struct blame_entry split[3]; + + split_overlap(split, e, tlno, plno, same, parent); + if (split[1].suspect) + split_blame(sb, split, e); + decref_split(split); +} + +/* + * Find the line number of the last line the target is suspected for. + */ +static int find_last_in_target(struct scoreboard *sb, struct origin *target) +{ + struct blame_entry *e; + int last_in_target = -1; + + for (e = sb->ent; e; e = e->next) { + if (e->guilty || !same_suspect(e->suspect, target)) + continue; + if (last_in_target < e->s_lno + e->num_lines) + last_in_target = e->s_lno + e->num_lines; + } + return last_in_target; +} + +/* + * Process one hunk from the patch between the current suspect for + * blame_entry e and its parent. Find and split the overlap, and + * pass blame to the overlapping part to the parent. + */ +static void blame_chunk(struct scoreboard *sb, + int tlno, int plno, int same, + struct origin *target, struct origin *parent) +{ + struct blame_entry *e; + + for (e = sb->ent; e; e = e->next) { + if (e->guilty || !same_suspect(e->suspect, target)) + continue; + if (same <= e->s_lno) + continue; + if (tlno < e->s_lno + e->num_lines) + blame_overlap(sb, e, tlno, plno, same, parent); + } +} + +struct blame_chunk_cb_data { + struct scoreboard *sb; + struct origin *target; + struct origin *parent; + long plno; + long tlno; +}; + +static void blame_chunk_cb(void *data, long same, long p_next, long t_next) +{ + struct blame_chunk_cb_data *d = data; + blame_chunk(d->sb, d->tlno, d->plno, same, d->target, d->parent); + d->plno = p_next; + d->tlno = t_next; +} + +/* + * 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 int pass_blame_to_parent(struct scoreboard *sb, + struct origin *target, + struct origin *parent) +{ + int last_in_target; + mmfile_t file_p, file_o; + struct blame_chunk_cb_data d = { sb, target, parent, 0, 0 }; + xpparam_t xpp; + xdemitconf_t xecfg; + + last_in_target = find_last_in_target(sb, target); + if (last_in_target < 0) + return 1; /* nothing remains for this target */ + + fill_origin_blob(parent, &file_p); + fill_origin_blob(target, &file_o); + num_get_patch++; + + memset(&xpp, 0, sizeof(xpp)); + xpp.flags = xdl_opts; + memset(&xecfg, 0, sizeof(xecfg)); + xecfg.ctxlen = 0; + xdi_diff_hunks(&file_p, &file_o, blame_chunk_cb, &d, &xpp, &xecfg); + /* The rest (i.e. anything after tlno) are the same as the parent */ + blame_chunk(sb, d.tlno, d.plno, last_in_target, target, parent); + + return 0; +} + +/* + * 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. + */ +static unsigned ent_score(struct scoreboard *sb, struct blame_entry *e) +{ + unsigned score; + const char *cp, *ep; + + if (e->score) + return e->score; + + score = 1; + cp = nth_line(sb, e->lno); + ep = 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 this[] 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 this and best_so_far and copying this into + * bst_so_far as needed. + */ +static void copy_split_if_better(struct scoreboard *sb, + struct blame_entry *best_so_far, + struct blame_entry *this) +{ + int i; + + if (!this[1].suspect) + return; + if (best_so_far[1].suspect) { + if (ent_score(sb, &this[1]) < ent_score(sb, &best_so_far[1])) + return; + } + + for (i = 0; i < 3; i++) + origin_incref(this[i].suspect); + decref_split(best_so_far); + memcpy(best_so_far, this, 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 scoreboard *sb, + struct blame_entry *ent, + int tlno, int plno, int same, + struct origin *parent, + struct blame_entry *split) +{ + if (ent->num_lines <= tlno) + return; + if (tlno < same) { + struct blame_entry this[3]; + tlno += ent->s_lno; + same += ent->s_lno; + split_overlap(this, ent, tlno, plno, same, parent); + copy_split_if_better(sb, split, this); + decref_split(this); + } +} + +struct handle_split_cb_data { + struct scoreboard *sb; + struct blame_entry *ent; + struct origin *parent; + struct blame_entry *split; + long plno; + long tlno; +}; + +static void handle_split_cb(void *data, long same, long p_next, long t_next) +{ + struct handle_split_cb_data *d = data; + handle_split(d->sb, d->ent, d->tlno, d->plno, same, d->parent, d->split); + d->plno = p_next; + d->tlno = t_next; +} + +/* + * 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 scoreboard *sb, + struct blame_entry *ent, + struct origin *parent, + struct blame_entry *split, + mmfile_t *file_p) +{ + const char *cp; + int cnt; + mmfile_t file_o; + struct handle_split_cb_data d = { sb, ent, parent, split, 0, 0 }; + xpparam_t xpp; + xdemitconf_t xecfg; + + /* + * Prepare mmfile that contains only the lines in ent. + */ + cp = nth_line(sb, ent->lno); + file_o.ptr = (char *) cp; + cnt = ent->num_lines; + + while (cnt && cp < sb->final_buf + sb->final_buf_size) { + if (*cp++ == '\n') + cnt--; + } + file_o.size = cp - file_o.ptr; + + /* + * file_o is a part of final image we are annotating. + * file_p partially may match that image. + */ + memset(&xpp, 0, sizeof(xpp)); + xpp.flags = xdl_opts; + memset(&xecfg, 0, sizeof(xecfg)); + xecfg.ctxlen = 1; + memset(split, 0, sizeof(struct blame_entry [3])); + xdi_diff_hunks(file_p, &file_o, handle_split_cb, &d, &xpp, &xecfg); + /* remainder, if any, all match the preimage */ + handle_split(sb, ent, d.tlno, d.plno, ent->num_lines, parent, split); +} + +/* + * See if lines currently target is suspected for can be attributed to + * parent. + */ +static int find_move_in_parent(struct scoreboard *sb, + struct origin *target, + struct origin *parent) +{ + int last_in_target, made_progress; + struct blame_entry *e, split[3]; + mmfile_t file_p; + + last_in_target = find_last_in_target(sb, target); + if (last_in_target < 0) + return 1; /* nothing remains for this target */ + + fill_origin_blob(parent, &file_p); + if (!file_p.ptr) + return 0; + + made_progress = 1; + while (made_progress) { + made_progress = 0; + for (e = sb->ent; e; e = e->next) { + if (e->guilty || !same_suspect(e->suspect, target) || + ent_score(sb, e) < blame_move_score) + continue; + find_copy_in_blob(sb, e, parent, split, &file_p); + if (split[1].suspect && + blame_move_score < ent_score(sb, &split[1])) { + split_blame(sb, split, e); + made_progress = 1; + } + decref_split(split); + } + } + return 0; +} + +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 scoreboard *sb, + struct origin *target, + int min_score, + int *num_ents_p) +{ + struct blame_entry *e; + int num_ents, i; + struct blame_list *blame_list = NULL; + + for (e = sb->ent, num_ents = 0; e; e = e->next) + if (!e->scanned && !e->guilty && + same_suspect(e->suspect, target) && + min_score < ent_score(sb, e)) + num_ents++; + if (num_ents) { + blame_list = xcalloc(num_ents, sizeof(struct blame_list)); + for (e = sb->ent, i = 0; e; e = e->next) + if (!e->scanned && !e->guilty && + same_suspect(e->suspect, target) && + min_score < ent_score(sb, e)) + blame_list[i++].ent = e; + } + *num_ents_p = num_ents; + return blame_list; +} + +/* + * Reset the scanned status on all entries. + */ +static void reset_scanned_flag(struct scoreboard *sb) +{ + struct blame_entry *e; + for (e = sb->ent; e; e = e->next) + e->scanned = 0; +} + +/* + * 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 int find_copy_in_parent(struct scoreboard *sb, + struct origin *target, + struct commit *parent, + struct origin *porigin, + int opt) +{ + struct diff_options diff_opts; + const char *paths[1]; + int i, j; + int retval; + struct blame_list *blame_list; + int num_ents; + + blame_list = setup_blame_list(sb, target, blame_copy_score, &num_ents); + if (!blame_list) + return 1; /* nothing remains for this target */ + + diff_setup(&diff_opts); + DIFF_OPT_SET(&diff_opts, RECURSIVE); + diff_opts.output_format = DIFF_FORMAT_NO_OUTPUT; + + paths[0] = NULL; + diff_tree_setup_paths(paths, &diff_opts); + if (diff_setup_done(&diff_opts) < 0) + die("diff-setup"); + + /* 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_sha1() 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_OPT_SET(&diff_opts, FIND_COPIES_HARDER); + + if (is_null_sha1(target->commit->object.sha1)) + do_diff_cache(parent->tree->object.sha1, &diff_opts); + else + diff_tree_sha1(parent->tree->object.sha1, + target->commit->tree->object.sha1, + "", &diff_opts); + + if (!DIFF_OPT_TST(&diff_opts, FIND_COPIES_HARDER)) + diffcore_std(&diff_opts); + + retval = 0; + while (1) { + int made_progress = 0; + + for (i = 0; i < diff_queued_diff.nr; i++) { + struct diff_filepair *p = diff_queued_diff.queue[i]; + struct origin *norigin; + mmfile_t file_p; + struct blame_entry this[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(sb, parent, p->one->path); + hashcpy(norigin->blob_sha1, p->one->sha1); + fill_origin_blob(norigin, &file_p); + if (!file_p.ptr) + continue; + + for (j = 0; j < num_ents; j++) { + find_copy_in_blob(sb, blame_list[j].ent, + norigin, this, &file_p); + copy_split_if_better(sb, blame_list[j].split, + this); + decref_split(this); + } + origin_decref(norigin); + } + + for (j = 0; j < num_ents; j++) { + struct blame_entry *split = blame_list[j].split; + if (split[1].suspect && + blame_copy_score < ent_score(sb, &split[1])) { + split_blame(sb, split, blame_list[j].ent); + made_progress = 1; + } + else + blame_list[j].ent->scanned = 1; + decref_split(split); + } + free(blame_list); + + if (!made_progress) + break; + blame_list = setup_blame_list(sb, target, blame_copy_score, &num_ents); + if (!blame_list) { + retval = 1; + break; + } + } + reset_scanned_flag(sb); + diff_flush(&diff_opts); + diff_tree_release_paths(&diff_opts); + return retval; +} + +/* + * 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 scoreboard *sb, + struct origin *origin, struct origin *porigin) +{ + struct blame_entry *e; + + if (!porigin->file.ptr && origin->file.ptr) { + /* Steal its file */ + porigin->file = origin->file; + origin->file.ptr = NULL; + } + for (e = sb->ent; e; e = e->next) { + if (!same_suspect(e->suspect, origin)) + continue; + origin_incref(porigin); + origin_decref(e->suspect); + e->suspect = porigin; + } +} + +/* + * 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) +{ + if (!reverse) + return commit->parents; + return lookup_decoration(&revs->children, &commit->object); +} + +static int num_scapegoats(struct rev_info *revs, struct commit *commit) +{ + int cnt; + struct commit_list *l = first_scapegoat(revs, commit); + for (cnt = 0; l; l = l->next) + cnt++; + return cnt; +} + +#define MAXSG 16 + +static void pass_blame(struct scoreboard *sb, struct 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 origin *sg_buf[MAXSG]; + struct origin *porigin, **sg_origin = sg_buf; + + num_sg = num_scapegoats(revs, commit); + 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; pass++) { + struct origin *(*find)(struct scoreboard *, + struct commit *, struct origin *); + find = pass ? find_rename : find_origin; + + for (i = 0, sg = first_scapegoat(revs, commit); + 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, p, origin); |