git-pickaxe: retire pickaxe

Just make it take over blame's place.  Documentation and command
have all stopped mentioning "git-pickaxe".  The built-in synonym
is left in the command table, so you can still say "git pickaxe",
but it probably is a good idea to retire it as well.

Signed-off-by: Junio C Hamano <junkio@cox.net>

1 files changed, 1889 insertions, 0 deletions

diff --git a/builtin-blame.c b/builtin-blame.c
new file mode 100644
index 0000000000..16660221c3
--- /dev/null
+++ b/builtin-blame.c
@@ -0,0 +1,1889 @@
+/*
+ * Pickaxe
+ *
+ * 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 "xdiff-interface.h"
+
+#include <time.h>
+#include <sys/time.h>
+#include <regex.h>
+
+static char blame_usage[] =
+"git-blame [-c] [-l] [-t] [-f] [-n] [-p] [-L n,m] [-S <revs-file>] [-M] [-C] [-C] [commit] [--] file\n"
+"  -c, --compatibility Use the same output mode as git-annotate (Default: off)\n"
+"  -l, --long          Show long commit SHA1 (Default: off)\n"
+"  -t, --time          Show raw timestamp (Default: off)\n"
+"  -f, --show-name     Show original filename (Default: auto)\n"
+"  -n, --show-number   Show original linenumber (Default: off)\n"
+"  -p, --porcelain     Show in a format designed for machine consumption\n"
+"  -L n,m              Process only line range n,m, counting from 1\n"
+"  -M, -C              Find line movements within and across files\n"
+"  -S revs-file        Use revisions from revs-file instead of calling git-rev-list\n";
+
+static int longest_file;
+static int longest_author;
+static int max_orig_digits;
+static int max_digits;
+static int max_score_digits;
+
+#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
+
+/*
+ * 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 commit *commit;
+	mmfile_t file;
+	unsigned char blob_sha1[20];
+	char path[FLEX_ARRAY];
+};
+
+static char *fill_origin_blob(struct origin *o, mmfile_t *file)
+{
+	if (!o->file.ptr) {
+		char type[10];
+		num_read_blob++;
+		file->ptr = read_sha1_file(o->blob_sha1, type,
+					   (unsigned long *)(&(file->size)));
+		o->file = *file;
+	}
+	else
+		*file = o->file;
+	return file->ptr;
+}
+
+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->file.ptr)
+			free(o->file.ptr);
+		memset(o, 0, sizeof(*o));
+		free(o);
+	}
+}
+
+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;
+
+	/* 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;
+};
+
+struct scoreboard {
+	/* the final commit (i.e. where we started digging from) */
+	struct commit *final;
+
+	const char *path;
+
+	/* the contents in the final; pointed into by buf pointers of
+	 * blame_entries
+	 */
+	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 int cmp_suspect(struct origin *a, struct origin *b)
+{
+	int cmp = hashcmp(a->commit->object.sha1, b->commit->object.sha1);
+	if (cmp)
+		return cmp;
+	return strcmp(a->path, b->path);
+}
+
+#define cmp_suspect(a, b) ( ((a)==(b)) ? 0 : cmp_suspect(a,b) )
+
+static void sanity_check_refcnt(struct scoreboard *);
+
+static void coalesce(struct scoreboard *sb)
+{
+	struct blame_entry *ent, *next;
+
+	for (ent = sb->ent; ent && (next = ent->next); ent = next) {
+		if (!cmp_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);
+}
+
+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;
+}
+
+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);
+}
+
+static int fill_blob_sha1(struct origin *origin)
+{
+	unsigned mode;
+	char type[10];
+
+	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, type, NULL) ||
+	    strcmp(type, blob_type))
+		goto error_out;
+	return 0;
+ error_out:
+	hashclr(origin->blob_sha1);
+	return -1;
+}
+
+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) {
+		/* This is a freestanding copy of origin and not
+		 * refcounted.
+		 */
+		struct origin *cached = parent->util;
+		if (!strcmp(cached->path, origin->path)) {
+			porigin = get_origin(sb, parent, cached->path);
+			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_opts.recursive = 1;
+	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");
+	diff_tree_sha1(parent->tree->object.sha1,
+		       origin->commit->tree->object.sha1,
+		       "", &diff_opts);
+	diffcore_std(&diff_opts);
+
+	/* It is either one entry that says "modified", or "created",
+	 * or nothing.
+	 */
+	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 if (diff_queued_diff.nr != 1)
+		die("internal error in blame::find_origin");
+	else {
+		struct diff_filepair *p = diff_queued_diff.queue[0];
+		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);
+	if (porigin) {
+		struct origin *cached;
+		cached = make_origin(porigin->commit, porigin->path);
+		hashcpy(cached->blob_sha1, porigin->blob_sha1);
+		parent->util = cached;
+	}
+	return porigin;
+}
+
+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_opts.recursive = 1;
+	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");
+	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);
+	return porigin;
+}
+
+struct chunk {
+	/* line number in postimage; up to but not including this
+	 * line is the same as preimage
+	 */
+	int same;
+
+	/* preimage line number after this chunk */
+	int p_next;
+
+	/* postimage line number after this chunk */
+	int t_next;
+};
+
+struct patch {
+	struct chunk *chunks;
+	int num;
+};
+
+struct blame_diff_state {
+	struct xdiff_emit_state xm;
+	struct patch *ret;
+	unsigned hunk_post_context;
+	unsigned hunk_in_pre_context : 1;
+};
+
+static void process_u_diff(void *state_, char *line, unsigned long len)
+{
+	struct blame_diff_state *state = state_;
+	struct chunk *chunk;
+	int off1, off2, len1, len2, num;
+
+	num = state->ret->num;
+	if (len < 4 || line[0] != '@' || line[1] != '@') {
+		if (state->hunk_in_pre_context && line[0] == ' ')
+			state->ret->chunks[num - 1].same++;
+		else {
+			state->hunk_in_pre_context = 0;
+			if (line[0] == ' ')
+				state->hunk_post_context++;
+			else
+				state->hunk_post_context = 0;
+		}
+		return;
+	}
+
+	if (num && state->hunk_post_context) {
+		chunk = &state->ret->chunks[num - 1];
+		chunk->p_next -= state->hunk_post_context;
+		chunk->t_next -= state->hunk_post_context;
+	}
+	state->ret->num = ++num;
+	state->ret->chunks = xrealloc(state->ret->chunks,
+				      sizeof(struct chunk) * num);
+	chunk = &state->ret->chunks[num - 1];
+	if (parse_hunk_header(line, len, &off1, &len1, &off2, &len2)) {
+		state->ret->num--;
+		return;
+	}
+
+	/* Line numbers in patch output are one based. */
+	off1--;
+	off2--;
+
+	chunk->same = len2 ? off2 : (off2 + 1);
+
+	chunk->p_next = off1 + (len1 ? len1 : 1);
+	chunk->t_next = chunk->same + len2;
+	state->hunk_in_pre_context = 1;
+	state->hunk_post_context = 0;
+}
+
+static struct patch *compare_buffer(mmfile_t *file_p, mmfile_t *file_o,
+				    int context)
+{
+	struct blame_diff_state state;
+	xpparam_t xpp;
+	xdemitconf_t xecfg;
+	xdemitcb_t ecb;
+
+	xpp.flags = XDF_NEED_MINIMAL;
+	xecfg.ctxlen = context;
+	xecfg.flags = 0;
+	ecb.outf = xdiff_outf;
+	ecb.priv = &state;
+	memset(&state, 0, sizeof(state));
+	state.xm.consume = process_u_diff;
+	state.ret = xmalloc(sizeof(struct patch));
+	state.ret->chunks = NULL;
+	state.ret->num = 0;
+
+	xdl_diff(file_p, file_o, &xpp, &xecfg, &ecb);
+
+	if (state.ret->num) {
+		struct chunk *chunk;
+		chunk = &state.ret->chunks[state.ret->num - 1];
+		chunk->p_next -= state.hunk_post_context;
+		chunk->t_next -= state.hunk_post_context;
+	}
+	return state.ret;
+}
+
+static struct patch *get_patch(struct origin *parent, struct origin *origin)
+{
+	mmfile_t file_p, file_o;
+	struct patch *patch;
+
+	fill_origin_blob(parent, &file_p);
+	fill_origin_blob(origin, &file_o);
+	if (!file_p.ptr || !file_o.ptr)
+		return NULL;
+	patch = compare_buffer(&file_p, &file_o, 0);
+	num_get_patch++;
+	return patch;
+}
+
+static void free_patch(struct patch *p)
+{
+	free(p->chunks);
+	free(p);
+}
+
+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;
+}
+
+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];
+}
+
+static void split_overlap(struct blame_entry *split,
+			  struct blame_entry *e,
+			  int tlno, int plno, int same,
+			  struct origin *parent)
+{
+	/* 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 ----->
+	 *                   <------>
+	 *                   <------------>
+	 *             <------------>
+	 *             <------------------>
+	 *
+	 * Potentially we need to split e into three parts; before
+	 * this chunk, the chunk to be blamed for parent, and after
+	 * that portion.
+	 */
+	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 (split[1].num_lines < 1)
+		return;
+	split[1].suspect = origin_incref(parent);
+}
+
+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) {
+		/* we need to split e into two and add another for parent */
+		dup_entry(e, &split[0]);
+
+		new_entry = xmalloc(sizeof(*new_entry));
+		memcpy(new_entry, &(split[2]), sizeof(struct blame_entry));
+		add_blame_entry(sb, new_entry);
+
+		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)
+		/* parent covers the entire area */
+		dup_entry(e, &split[1]);
+	else if (split[0].suspect) {
+		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 {
+		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");
+		}
+	}
+}
+
+static void decref_split(struct blame_entry *split)
+{
+	int i;
+
+	for (i = 0; i < 3; i++)
+		origin_decref(split[i].suspect);
+}
+
+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);
+}
+
+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 || cmp_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;
+}
+
+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 || cmp_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);
+	}
+}
+
+static int pass_blame_to_parent(struct scoreboard *sb,
+				struct origin *target,
+				struct origin *parent)
+{
+	int i, last_in_target, plno, tlno;
+	struct patch *patch;
+
+	last_in_target = find_last_in_target(sb, target);
+	if (last_in_target < 0)
+		return 1; /* nothing remains for this target */
+
+	patch = get_patch(parent, target);
+	plno = tlno = 0;
+	for (i = 0; i < patch->num; i++) {
+		struct chunk *chunk = &patch->chunks[i];
+
+		blame_chunk(sb, tlno, plno, chunk->same, target, parent);
+		plno = chunk->p_next;
+		tlno = chunk->t_next;
+	}
+	/* rest (i.e. anything above tlno) are the same as parent */
+	blame_chunk(sb, tlno, plno, last_in_target, target, parent);
+
+	free_patch(patch);
+	return 0;
+}
+
+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;
+}
+
+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]));
+}
+
+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 patch *patch;
+	int i, plno, tlno;
+
+	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;
+
+	patch = compare_buffer(file_p, &file_o, 1);
+
+	memset(split, 0, sizeof(struct blame_entry [3]));
+	plno = tlno = 0;
+	for (i = 0; i < patch->num; i++) {
+		struct chunk *chunk = &patch->chunks[i];
+
+		/* tlno to chunk->same are the same as ent */
+		if (ent->num_lines <= tlno)
+			break;
+		if (tlno < chunk->same) {
+			struct blame_entry this[3];
+			split_overlap(this, ent,
+				      tlno + ent->s_lno, plno,
+				      chunk->same + ent->s_lno,
+				      parent);
+			copy_split_if_better(sb, split, this);
+			decref_split(this);
+		}
+		plno = chunk->p_next;
+		tlno = chunk->t_next;
+	}
+	free_patch(patch);
+}
+
+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 || cmp_suspect(e->suspect, target))
+				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];
+};
+
+static struct blame_list *setup_blame_list(struct scoreboard *sb,
+					   struct origin *target,
+					   int *num_ents_p)
+{
+	struct blame_entry *e;
+	int num_ents, i;
+	struct blame_list *blame_list = NULL;
+
+	/* Count the number of entries the target is suspected for,
+	 * and prepare a list of entry and the best split.
+	 */
+	for (e = sb->ent, num_ents = 0; e; e = e->next)
+		if (!e->guilty && !cmp_suspect(e->suspect, target))
+			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->guilty && !cmp_suspect(e->suspect, target))
+				blame_list[i++].ent = e;
+	}
+	*num_ents_p = num_ents;
+	return blame_list;
+}
+
+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, &num_ents);
+	if (!blame_list)
+		return 1; /* nothing remains for this target */
+
+	diff_setup(&diff_opts);
+	diff_opts.recursive = 1;
+	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_HARDER) &&
+	    (!porigin || strcmp(target->path, porigin->path)))
+		diff_opts.find_copies_harder = 1;
+
+	diff_tree_sha1(parent->tree->object.sha1,
+		       target->commit->tree->object.sha1,
+		       "", &diff_opts);
+
+	if (!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 (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;
+			}
+			decref_split(split);
+		}
+		free(blame_list);
+
+		if (!made_progress)
+			break;
+		blame_list = setup_blame_list(sb, target, &num_ents);
+		if (!blame_list) {
+			retval = 1;
+			break;
+		}
+	}
+	diff_flush(&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 (cmp_suspect(e->suspect, origin))
+			continue;
+		origin_incref(porigin);
+		origin_decref(e->suspect);
+		e->suspect = porigin;
+	}
+}
+
+#define MAXPARENT 16
+
+static void pass_blame(struct scoreboard *sb, struct origin *origin, int opt)
+{
+	int i, pass;
+	struct commit *commit = origin->commit;
+	struct commit_list *parent;
+	struct origin *parent_origin[MAXPARENT], *porigin;
+
+	memset(parent_origin, 0, sizeof(parent_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, parent = commit->parents;
+		     i < MAXPARENT && parent;
+		     parent = parent->next, i++) {
+			struct commit *p = parent->item;
+			int j, same;
+
+			if (parent_origin[i])
+				continue;
+			if (parse_commit(p))
+				continue;
+			porigin = find(sb, p, origin);
+			if (!porigin)
+				continue;
+			if (!hashcmp(porigin->blob_sha1, origin->blob_sha1)) {
+				pass_whole_blame(sb, origin, porigin);
+				origin_decref(porigin);
+				goto finish;
+			}
+			for (j = same = 0; j < i; j++)
+				if (parent_origin[j] &&
+				    !hashcmp(parent_origin[j]->blob_sha1,
+					     porigin->blob_sha1)) {
+					same = 1;
+					break;
+				}
+			if (!same)
+				parent_origin[i] = porigin;
+			else
+				origin_decref(porigin);
+		}
+	}
+
+	num_commits++;
+	for (i = 0, parent = commit->parents;
+	     i < MAXPARENT && parent;
+	     parent = parent->next, i++) {
+		struct origin *porigin = parent_origin[i];
+		if (!porigin)
+			continue;
+		if (pass_blame_to_parent(sb, origin, porigin))
+			goto finish;
+	}
+
+	/*
+	 * Optionally run "miff" to find moves in parents' files here.
+	 */
+	if (opt & PICKAXE_BLAME_MOVE)
+		for (i = 0, parent = commit->parents;
+		     i < MAXPARENT && parent;
+		     parent = parent->next, i++) {
+			struct origin *porigin = parent_origin[i];
+			if (!porigin)
+				continue;
+			if (find_move_in_parent(sb, origin, porigin))
+				goto finish;
+		}
+
+	/*
+	 * Optionally run "ciff" to find copies from parents' files here.
+	 */
+	if (opt & PICKAXE_BLAME_COPY)
+		for (i = 0, parent = commit->parents;
+		     i < MAXPARENT && parent;
+		     parent = parent->next, i++) {
+			struct origin *porigin = parent_origin[i];
+			if (find_copy_in_parent(sb, origin, parent->item,
+						porigin, opt))
+				goto finish;
+		}
+
+ finish:
+	for (i = 0; i < MAXPARENT; i++)
+		origin_decref(parent_origin[i]);
+}
+
+static void assign_blame(struct scoreboard *sb, struct rev_info *revs, int opt)
+{
+	while (1) {
+		struct blame_entry *ent;
+		struct commit *commit;
+		struct origin *suspect = NULL;
+
+		/* find one suspect to break down */
+		for (ent = sb->ent; !suspect && ent; ent = ent->next)
+			if (!ent->guilty)
+				suspect = ent->suspect;
+		if (!suspect)
+			return; /* all done */
+
+		origin_incref(suspect);
+		commit = suspect->commit;
+		if (!commit->object.parsed)
+			parse_commit(commit);
+		if (!(commit->object.flags & UNINTERESTING) &&
+		    !(revs->max_age != -1 && commit->date  < revs->max_age))
+			pass_blame(sb, suspect, opt);
+
+		/* Take responsibility for the remaining entries */
+		for (ent = sb->ent; ent; ent = ent->next)
+			if (!cmp_suspect(ent->suspect, suspect))
+				ent->guilty = 1;
+		origin_decref(suspect);
+
+		if (DEBUG) /* sanity */
+			sanity_check_refcnt(sb);
+	}
+}
+
+static const char *format_time(unsigned long time, const char *tz_str,
+			       int show_raw_time)
+{
+	static char time_buf[128];
+	time_t t = time;
+	int minutes, tz;
+	struct tm *tm;
+
+	if (show_raw_time) {
+		sprintf(time_buf, "%lu %s", time, tz_str);
+		return time_buf;
+	}
+
+	tz = atoi(tz_str);
+	minutes = tz < 0 ? -tz : tz;
+	minutes = (minutes / 100)*60 + (minutes % 100);
+	minutes = tz < 0 ? -minutes : minutes;
+	t = time + minutes * 60;
+	tm = gmtime(&t);
+
+	strftime(time_buf, sizeof(time_buf), "%Y-%m-%d %H:%M:%S ", tm);
+	strcat(time_buf, tz_str);
+	return time_buf;
+}
+
+struct commit_info
+{
+	char *author;
+	char *author_mail;
+	unsigned long author_time;
+	char *author_tz;
+
+	/* filled only when asked for details */
+	char *committer;
+	char *committer_mail;
+	unsigned long committer_time;
+	char *committer_tz;
+
+	char *summary;
+};
+
+static void get_ac_line(const char *inbuf, const char *what,
+			int bufsz, char *person, char **mail,
+			unsigned long *time, char **tz)
+{
+	int len;
+	char *tmp, *endp;
+
+	tmp = strstr(inbuf, what);
+	if (!tmp)
+		goto error_out;
+	tmp += strlen(what);
+	endp = strchr(tmp, '\n');
+	if (!endp)
+		len = strlen(tmp);
+	else
+		len = endp - tmp;
+	if (bufsz <= len) {
+	error_out:
+		/* Ugh */
+		person = *mail = *tz = "(unknown)";
+		*time = 0;
+		return;
+	}
+	memcpy(person, tmp, len);
+
+	tmp = person;
+	tmp += len;
+	*tmp = 0;
+	while (*tmp != ' ')
+		tmp--;
+	*tz = tmp+1;
+
+	*tmp = 0;
+	while (*tmp != ' ')
+		tmp--;
+	*time = strtoul(tmp, NULL, 10);
+
+	*tmp = 0;
+	while (*tmp != ' ')
+		tmp--;
+	*mail = tmp + 1;
+	*tmp = 0;
+}
+
+static void get_commit_info(struct commit *commit,
+			    struct commit_info *ret,
+			    int detailed)
+{
+	int len;
+	char *tmp, *endp;
+	static char author_buf[1024];
+	static char committer_buf[1024];
+	static char summary_buf[1024];
+
+	/* We've operated without save_commit_buffer, so
+	 * we now need to populate them for output.
+	 */
+	if (!commit->buffer) {
+		char type[20];
+		unsigned long size;
+		commit->buffer =
+			read_sha1_file(commit->object.sha1, type, &size);
+	}
+	ret->author = author_buf;
+	get_ac_line(commit->buffer, "\nauthor ",
+		    sizeof(author_buf), author_buf, &ret->author_mail,
+		    &ret->author_time, &ret->author_tz);
+
+	if (!detailed)
+		return;
+
+	ret->committer = committer_buf;
+	get_ac_line(commit->buffer, "\ncommitter ",
+		    sizeof(committer_buf), committer_buf, &ret->committer_mail,
+		    &ret->committer_time, &ret->committer_tz);
+
+	ret->summary = summary_buf;
+	tmp = strstr(commit->buffer, "\n\n");
+	if (!tmp) {
+	error_out:
+		sprintf(summary_buf, "(%s)", sha1_to_hex(commit->object.sha1));
+		return;
+	}
+	tmp += 2;
+	endp = strchr(tmp, '\n');
+	if (!endp)
+		goto error_out;
+	len = endp - tmp;
+	if (len >= sizeof(summary_buf))
+		goto error_out;
+	memcpy(summary_buf, tmp, len);
+	summary_buf[len] = 0;
+}
+
+#define OUTPUT_ANNOTATE_COMPAT	001
+#define OUTPUT_LONG_OBJECT_NAME	002
+#define OUTPUT_RAW_TIMESTAMP	004
+#define OUTPUT_PORCELAIN	010
+#define OUTPUT_SHOW_NAME	020
+#define OUTPUT_SHOW_NUMBER	040
+#define OUTPUT_SHOW_SCORE      0100
+
+static void emit_porcelain(struct scoreboard *sb, struct blame_entry *ent)
+{
+	int cnt;
+	const char *cp;
+	struct origin *suspect = ent->suspect;
+	char hex[41];
+
+	strcpy(hex, sha1_to_hex(suspect->commit->object.sha1));
+	printf("%s%c%d %d %d\n",
+	       hex,
+	       ent->guilty ? ' ' : '*', // purely for debugging
+	       ent->s_lno + 1,
+	       ent->lno + 1,
+	       ent->num_lines);
+	if (!(suspect->commit->object.flags & METAINFO_SHOWN)) {
+		struct commit_info ci;
+		suspect->commit->object.flags |= METAINFO_SHOWN;
+		get_commit_info(suspect->commit, &ci, 1);
+		printf("author %s\n", ci.author);
+		printf("author-mail %s\n", ci.author_mail);
+		printf("author-time %lu\n", ci.author_time);
+		printf("author-tz %s\n", ci.author_tz);
+		printf("committer %s\n", ci.committer);
+		printf("committer-mail %s\n", ci.committer_mail);
+		printf("committer-time %lu\n", ci.committer_time);
+		printf("committer-tz %s\n", ci.committer_tz);
+		printf("filename %s\n", suspect->path);
+		printf("summary %s\n", ci.summary);
+	}
+	else if (suspect->commit->object.flags & MORE_THAN_ONE_PATH)
+		printf("filename %s\n", suspect->path);
+
+	cp = nth_line(sb, ent->lno);
+	for (cnt = 0; cnt < ent->num_lines; cnt++) {
+		char ch;
+		if (cnt)
+			printf("%s %d %d\n", hex,
+			       ent->s_lno + 1 + cnt,
+			       ent->lno + 1 + cnt);
+		putchar('\t');
+		do {
+			ch = *cp++;
+			putchar(ch);
+		} while (ch != '\n' &&
+			 cp < sb->final_buf + sb->final_buf_size);
+	}
+}
+
+static void emit_other(struct scoreboard *sb, struct blame_entry *ent, int opt)
+{
+	int cnt;
+	const char *cp;
+	struct origin *suspect = ent->suspect;
+	struct commit_info ci;
+	char hex[41];
+	int show_raw_time = !!(opt & OUTPUT_RAW_TIMESTAMP);
+
+	get_commit_info(suspect->commit, &ci, 1);
+	strcpy(hex, sha1_to_hex(suspect->commit->object.sha1));
+
+	cp = nth_line(sb, ent->lno);
+	for (cnt = 0; cnt < ent->num_lines; cnt++) {
+		char ch;
+
+		printf("%.*s", (opt & OUTPUT_LONG_OBJECT_NAME) ? 40 : 8, hex);
+		if (opt & OUTPUT_ANNOTATE_COMPAT)
+			printf("\t(%10s\t%10s\t%d)", ci.author,
+			       format_time(ci.author_time, ci.author_tz,
+					   show_raw_time),
+			       ent->lno + 1 + cnt);
+		else {
+			if (opt & OUTPUT_SHOW_SCORE)
+				printf(" %*d %02d",
+				       max_score_digits, ent->score,
+				       ent->suspect->refcnt);
+			if (opt & OUTPUT_SHOW_NAME)
+				printf(" %-*.*s", longest_file, longest_file,
+				       suspect->path);
+			if (opt & OUTPUT_SHOW_NUMBER)
+				printf(" %*d", max_orig_digits,
+				       ent->s_lno + 1 + cnt);
+			printf(" (%-*.*s %10s %*d) ",
+			       longest_author, longest_author, ci.author,
+			       format_time(ci.author_time, ci.author_tz,
+					   show_raw_time),
+			       max_digits, ent->lno + 1 + cnt);
+		}
+		do {
+			ch = *cp++;
+			putchar(ch);
+		} while (ch != '\n' &&
+			 cp < sb->final_buf + sb->final_buf_size);
+	}
+}
+
+static void output(struct scoreboard *sb, int option)
+{
+	struct blame_entry *ent;
+
+	if (option & OUTPUT_PORCELAIN) {
+		for (ent = sb->ent; ent; ent = ent->next) {
+			struct blame_entry *oth;
+			struct origin *suspect = ent->suspect;
+			struct commit *commit = suspect->commit;
+			if (commit->object.flags & MORE_THAN_ONE_PATH)
+				continue;
+			for (oth = ent->next; oth; oth = oth->next) {
+				if ((oth->suspect->commit != commit) ||
+				    !strcmp(oth->suspect->path, suspect->path))
+					continue;
+				commit->object.flags |= MORE_THAN_ONE_PATH;
+				break;
+			}
+		}
+	}
+
+	for (ent = sb->ent; ent; ent = ent->next) {
+		if (option & OUTPUT_PORCELAIN)
+			emit_porcelain(sb, ent);
+		else {
+			emit_other(sb, ent, option);
+		}
+	}
+}
+
+static int prepare_lines(struct scoreboard *sb)
+{
+	const char *buf = sb->final_buf;
+	unsigned long len = sb->final_buf_size;
+	int num = 0, incomplete = 0, bol = 1;
+
+	if (len && buf[len-1] != '\n')
+		incomplete++; /* incomplete line at the end */
+	while (len--) {
+		if (bol) {
+			sb->lineno = xrealloc(sb->lineno,
+					      sizeof(int* ) * (num + 1));
+			sb->lineno[num] = buf - sb->final_buf;
+			bol = 0;
+		}
+		if (*buf++ == '\n') {
+			num++;
+			bol = 1;
+		}
+	}
+	sb->lineno = xrealloc(sb->lineno,
+			      sizeof(int* ) * (num + incomplete + 1));
+	sb->lineno[num + incomplete] = buf - sb->final_buf;
+	sb->num_lines = num + incomplete;
+	return sb->num_lines;
+}
+
+static int read_ancestry(const char *graft_file)
+{
+	FILE *fp = fopen(graft_file, "r");
+	char buf[1024];
+	if (!fp)
+		return -1;
+	while (fgets(buf, sizeof(buf), fp)) {
+		/* The format is just "Commit Parent1 Parent2 ...\n" */
+		int len = strlen(buf);
+		struct commit_graft *graft = read_graft_line(buf, len);
+		register_commit_graft(graft, 0);
+	}
+	fclose(fp);
+	return 0;
+}
+
+static int lineno_width(int lines)
+{
+        int i, width;
+
+        for (width = 1, i = 10; i <= lines + 1; width++)
+                i *= 10;
+        return width;
+}
+
+static void find_alignment(struct scoreboard *sb, int *option)
+{
+	int longest_src_lines = 0;
+	int longest_dst_lines = 0;
+	unsigned largest_score = 0;
+	struct blame_entry *e;
+
+	for (e = sb->ent; e; e = e->next) {
+		struct origin *suspect = e->suspect;
+		struct commit_info ci;
+		int num;
+
+		if (!(suspect->commit->object.flags & METAINFO_SHOWN)) {
+			suspect->commit->object.flags |= METAINFO_SHOWN;
+			get_commit_info(suspect->commit, &ci, 1);
+			if (strcmp(suspect->path, sb->path))
+				*option |= OUTPUT_SHOW_NAME;
+			num = strlen(suspect->path);
+			if (longest_file < num)
+				longest_file = num;
+			num = strlen(ci.author);
+			if (longest_author < num)
+				longest_author = num;
+		}
+		num = e->s_lno + e->num_lines;
+		if (longest_src_lines < num)
+			longest_src_lines = num;
+		num = e->lno + e->num_lines;
+		if (longest_dst_lines < num)
+			longest_dst_lines = num;
+		if (largest_score < ent_score(sb, e))
+			largest_score = ent_score(sb, e);
+	}
+	max_orig_digits = lineno_width(longest_src_lines);
+	max_digits = lineno_width(longest_dst_lines);
+	max_score_digits = lineno_width(largest_score);
+}
+
+static void sanity_check_refcnt(struct 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,
+				sha1_to_hex(ent->suspect->commit->object.sha1),
+				ent->suspect->refcnt);
+			baa = 1;
+		}
+	}
+	for (ent = sb->ent; ent; ent = ent->next) {
+		/* Mark the ones that haven't been checked */
+		if (0 < ent->suspect->refcnt)
+			ent->suspect->refcnt = -ent->suspect->refcnt;
+	}
+	for (ent = sb->ent; ent; ent = ent->next) {
+		/* then pick each and see if they have the the correct
+		 * refcnt.
+		 */
+		int found;
+		struct blame_entry *e;
+		struct origin *suspect = ent->suspect;
+
+		if (0 < suspect->refcnt)
+			continue;
+		suspect->refcnt = -suspect->refcnt; /* Unmark */
+		for (found = 0, e = sb->ent; e; e = e->next) {
+			if (e->suspect != suspect)
+				continue;
+			found++;
+		}
+		if (suspect->refcnt != found) {
+			fprintf(stderr, "%s in %s has refcnt %d, not %d\n",
+				ent->suspect->path,
+				sha1_to_hex(ent->suspect->commit->object.sha1),
+				ent->suspect->refcnt, found);
+			baa = 2;
+		}
+	}
+	if (baa) {
+		int opt = 0160;
+		find_alignment(sb, &opt);
+		output(sb, opt);
+		die("Baa %d!", baa);
+	}
+}
+
+static int has_path_in_work_tree(const char *path)
+{
+	struct stat st;
+	return !lstat(path, &st);
+}
+
+static unsigned parse_score(const char *arg)
+{
+	char *end;
+	unsigned long score = strtoul(arg, &end, 10);
+	if (*end)
+		return 0;
+	return score;
+}
+
+static const char *add_prefix(const char *prefix, const char *path)
+{
+	if (!prefix || !prefix[0])
+		return path;
+	return prefix_path(prefix, strlen(prefix), path);
+}
+
+static const char *parse_loc(const char *spec,
+			     struct scoreboard *sb, long lno,
+			     long begin, long *ret)
+{
+	char *term;
+	const char *line;
+	long num;
+	int reg_error;
+	regex_t regexp;
+	regmatch_t match[1];
+
+	/* Allow "-L <something>,+20" to mean starting at <something>
+	 * for 20 lines, or "-L <something>,-5" for 5 lines ending at
+	 * <something>.
+	 */
+	if (1 < begin && (spec[0] == '+' || spec[0] == '-')) {
+		num = strtol(spec + 1, &term, 10);
+		if (term != spec + 1) {
+			if (spec[0] == '-')
+				num = 0 - num;
+			if (0 < num)
+				*ret = begin + num - 2;
+			else if (!num)
+				*ret = begin;
+			else
+				*ret = begin + num;
+			return term;
+		}
+		return spec;
+	}
+	num = strtol(spec, &term, 10);
+	if (term != spec) {
+		*ret = num;
+		return term;
+	}
+	if (spec[0] != '/')
+		return spec;
+
+	/* it could be a regexp of form /.../ */
+	for (term = (char*) spec + 1; *term && *term != '/'; term++) {
+		if (*term == '\\')
+			term++;
+	}
+	if (*term != '/')
+		return spec;
+
+	/* try [spec+1 .. term-1] as regexp */
+	*term = 0;
+	begin--; /* input is in human terms */
+	line = nth_line(sb, begin);
+
+	if (!(reg_error = regcomp(&regexp, spec + 1, REG_NEWLINE)) &&
+	    !(reg_error = regexec(&regexp, line, 1, match, 0))) {
+		const char *cp = line + match[0].rm_so;
+		const char *nline;
+
+		while (begin++ < lno) {
+			nline = nth_line(sb, begin);
+			if (line <= cp && cp < nline)
+				break;
+			line = nline;
+		}
+		*ret = begin;
+		regfree(&regexp);
+		*term++ = '/';
+		return term;
+	}
+	else {
+		char errbuf[1024];
+		regerror(reg_error, &regexp, errbuf, 1024);
+		die("-L parameter '%s': %s", spec + 1, errbuf);
+	}
+}
+
+static void prepare_blame_range(struct scoreboard *sb,
+				const char *bottomtop,
+				long lno,
+				long *bottom, long *top)
+{
+	const char *term;
+
+	term = parse_loc(bottomtop, sb, lno, 1, bottom);
+	if (*term == ',') {
+		term = parse_loc(term + 1, sb, lno, *bottom + 1, top);
+		if (*term)
+			usage(blame_usage);
+	}
+	if (*term)
+		usage(blame_usage);
+}
+
+int cmd_blame(int argc, const char **argv, const char *prefix)
+{
+	struct rev_info revs;
+	const char *path;
+	struct scoreboard sb;
+	struct origin *o;
+	struct blame_entry *ent;
+	int i, seen_dashdash, unk, opt;
+	long bottom, top, lno;
+	int output_option = 0;
+	const char *revs_file = NULL;
+	const char *final_commit_name = NULL;
+	char type[10];
+	const char *bottomtop = NULL;
+
+	save_commit_buffer = 0;
+
+	opt = 0;
+	seen_dashdash = 0;
+	for (unk = i = 1; i < argc; i++) {
+		const char *arg = argv[i];
+		if (*arg != '-')
+			break;
+		else if (!strcmp("-c", arg))
+			output_option |= OUTPUT_ANNOTATE_COMPAT;
+		else if (!strcmp("-t", arg))
+			output_option |= OUTPUT_RAW_TIMESTAMP;
+		else if (!strcmp("-l", arg))
+			output_option |= OUTPUT_LONG_OBJECT_NAME;
+		else if (!strcmp("-S", arg) && ++i < argc)
+			revs_file = argv[i];
+		else if (!strncmp("-M", arg, 2)) {
+			opt |= PICKAXE_BLAME_MOVE;
+			blame_move_score = parse_score(arg+2);
+		}
+		else if (!strncmp("-C", arg, 2)) {
+			if (opt & PICKAXE_BLAME_COPY)
+				opt |= PICKAXE_BLAME_COPY_HARDER;
+			opt |= PICKAXE_BLAME_COPY | PICKAXE_BLAME_MOVE;
+			blame_copy_score = parse_score(arg+2);
+		}
+		else if (!strncmp("-L", arg, 2)) {
+			if (!arg[2]) {
+				if (++i >= argc)
+					usage(blame_usage);
+				arg = argv[i];
+			}
+			else
+				arg += 2;
+			if (bottomtop)
+				die("More than one '-L n,m' option given");
+			bottomtop = arg;
+		}
+		else if (!strcmp("--score-debug", arg))
+			output_option |= OUTPUT_SHOW_SCORE;
+		else if (!strcmp("-f", arg) ||
+			 !strcmp("--show-name", arg))
+			output_option |= OUTPUT_SHOW_NAME;
+		else if (!strcmp("-n", arg) ||
+			 !strcmp("--show-number", arg))
+			output_option |= OUTPUT_SHOW_NUMBER;
+		else if (!strcmp("-p", arg) ||
+			 !strcmp("--porcelain", arg))
+			output_option |= OUTPUT_PORCELAIN;
+		else if (!strcmp("--", arg)) {
+			seen_dashdash = 1;
+			i++;
+			break;
+		}
+		else
+			argv[unk++] = arg;
+	}
+
+	if (!blame_move_score)
+		blame_move_score = BLAME_DEFAULT_MOVE_SCORE;
+	if (!blame_copy_score)
+		blame_copy_score = BLAME_DEFAULT_COPY_SCORE;
+
+	/* We have collected options unknown to us in argv[1..unk]
+	 * which are to be passed to revision machinery if we are
+	 * going to do the "bottom" procesing.
+	 *
+	 * The remaining are:
+	 *
+	 * (1) if seen_dashdash, its either
+	 *     "-options -- <path>" or
+	 *     "-options -- <path> <rev>".
+	 *     but the latter is allowed only if there is no
+	 *     options that we passed to revision machinery.
+	 *
+	 * (2) otherwise, we may have "--" somewhere later and
+	 *     might be looking at the first one of multiple 'rev'
+	 *     parameters (e.g. " master ^next ^maint -- path").
+	 *     See if there is a dashdash first, and give the
+	 *     arguments before that to revision machinery.
+	 *     After that there must be one 'path'.
+	 *
+	 * (3) otherwise, its one of the three:
+	 *     "-options <path> <rev>"
+	 *     "-options <rev> <path>"
+	 *     "-options <path>"
+	 *     but again the first one is allowed only if
+	 *     there is no options that we passed to revision
+	 *     machinery.
+	 */
+
+	if (seen_dashdash) {
+		/* (1) */
+		if (argc <= i)
+			usage(blame_usage);
+		path = add_prefix(prefix, argv[i]);
+		if (i + 1 == argc - 1) {
+			if (unk != 1)
+				usage(blame_usage);
+			argv[unk++] = argv[i + 1];
+		}
+		else if (i + 1 != argc)
+			/* garbage at end */
+			usage(blame_usage);
+	}
+	else {
+		int j;
+		for (j = i; !seen_dashdash && j < argc; j++)
+			if (!strcmp(argv[j], "--"))
+				seen_dashdash = j;
+		if (seen_dashdash) {
+			if (seen_dashdash + 1 != argc - 1)
+				usage(blame_usage);
+			path = add_prefix(prefix, argv[seen_dashdash + 1]);
+			for (j = i; j < seen_dashdash; j++)
+				argv[unk++] = argv[j];
+		}
+		else {
+			/* (3) */
+			path = add_prefix(prefix, argv[i]);
+			if (i + 1 == argc - 1) {
+				final_commit_name = argv[i + 1];
+
+				/* if (unk == 1) we could be getting
+				 * old-style
+				 */
+				if (unk == 1 && !has_path_in_work_tree(path)) {
+					path = add_prefix(prefix, argv[i + 1]);
+					final_commit_name = argv[i];
+				}
+			}
+			else if (i != argc - 1)
+				usage(blame_usage); /* garbage at end */
+
+			if (!has_path_in_work_tree(path))
+				die("cannot stat path %s: %s",
+				    path, strerror(errno));
+		}
+	}
+
+	if (final_commit_name)
+		argv[unk++] = final_commit_name;
+
+	/* Now we got rev and path.  We do not want the path pruning
+	 * but we may want "bottom" processing.
+	 */
+	argv[unk] = NULL;
+
+	init_revisions(&revs, NULL);
+	setup_revisions(unk, argv, &revs, "HEAD");
+	memset(&sb, 0, sizeof(sb));
+
+	/* There must be one and only one positive commit in the
+	 * revs->pending array.
+	 */
+	for (i = 0; i < revs.pending.nr; i++) {
+		struct object *obj = revs.pending.objects[i].item;
+		if (obj->flags & UNINTERESTING)
+			continue;
+		while (obj->type == OBJ_TAG)
+			obj = deref_tag(obj, NULL, 0);
+		if (obj->type != OBJ_COMMIT)
+			die("Non commit %s?",
+			    revs.pending.objects[i].name);
+		if (sb.final)
+			die("More than one commit to dig from %s and %s?",
+			    revs.pending.objects[i].name,
+			    final_commit_name);
+		sb.final = (struct commit *) obj;
+		final_commit_name = revs.pending.objects[i].name;
+	}
+
+	if (!sb.final) {
+		/* "--not A B -- path" without anything positive */
+		unsigned char head_sha1[20];
+
+		final_commit_name = "HEAD";
+		if (get_sha1(final_commit_name, head_sha1))
+			die("No such ref: HEAD");
+		sb.final = lookup_commit_reference(head_sha1);
+		add_pending_object(&revs, &(sb.final->object), "HEAD");
+	}
+
+	/* If we have bottom, this will mark the ancestors of the
+	 * bottom commits we would reach while traversing as
+	 * uninteresting.
+	 */
+	prepare_revision_walk(&revs);
+
+	o = get_origin(&sb, sb.final, path);
+	if (fill_blob_sha1(o))
+		die("no such path %s in %s", path, final_commit_name);
+
+	sb.final_buf = read_sha1_file(o->blob_sha1, type, &sb.final_buf_size);
+	num_read_blob++;
+	lno = prepare_lines(&sb);
+
+	bottom = top = 0;
+	if (bottomtop)
+		prepare_blame_range(&sb, bottomtop, lno, &bottom, &top);
+	if (bottom && top && top < bottom) {
+		long tmp;
+		tmp = top; top = bottom; bottom = tmp;
+	}
+	if (bottom < 1)
+		bottom = 1;
+	if (top < 1)
+		top = lno;
+	bottom--;
+	if (lno < top)
+		die("file %s has only %lu lines", path, lno);
+
+	ent = xcalloc(1, sizeof(*ent));
+	ent->lno = bottom;
+	ent->num_lines = top - bottom;
+	ent->suspect = o;
+	ent->s_lno = bottom;
+
+	sb.ent = ent;
+	sb.path = path;
+
+	if (revs_file && read_ancestry(revs_file))
+		die("reading graft file %s failed: %s",
+		    revs_file, strerror(errno));
+
+	assign_blame(&sb, &revs, opt);
+
+	coalesce(&sb);
+
+	if (!(output_option & OUTPUT_PORCELAIN))
+		find_alignment(&sb, &output_option);
+
+	output(&sb, output_option);
+	free((void *)sb.final_buf);
+	for (ent = sb.ent; ent; ) {
+		struct blame_entry *e = ent->next;
+		free(ent);
+		ent = e;
+	}
+
+	if (DEBUG) {
+		printf("num read blob: %d\n", num_read_blob);
+		printf("num get patch: %d\n", num_get_patch);
+		printf("num commits: %d\n", num_commits);
+	}
+	return 0;
+}