1 files changed, 368 insertions, 378 deletions

diff --git a/builtin/am.c b/builtin/am.c
index b77bf11..5e643e2 100644
--- a/builtin/am.c
+++ b/builtin/am.c
@@ -4,8 +4,9 @@
  * Based on git-am.sh by Junio C Hamano.
  */
 #include "cache.h"
+#include "config.h"
 #include "builtin.h"
-#include "exec_cmd.h"
+#include "exec-cmd.h"
 #include "parse-options.h"
 #include "dir.h"
 #include "run-command.h"
@@ -28,6 +29,10 @@
 #include "rerere.h"
 #include "prompt.h"
 #include "mailinfo.h"
+#include "apply.h"
+#include "string-list.h"
+#include "packfile.h"
+#include "repository.h"
 
 /**
  * Returns 1 if the file is empty or does not exist, 0 otherwise.
@@ -108,7 +113,7 @@ struct am_state {
 	size_t msg_len;
 
 	/* when --rebasing, records the original commit the patch came from */
-	unsigned char orig_commit[GIT_SHA1_RAWSZ];
+	struct object_id orig_commit;
 
 	/* number of digits in patch filename */
 	int prec;
@@ -132,17 +137,15 @@ struct am_state {
 };
 
 /**
- * Initializes am_state with the default values. The state directory is set to
- * dir.
+ * Initializes am_state with the default values.
  */
-static void am_state_init(struct am_state *state, const char *dir)
+static void am_state_init(struct am_state *state)
 {
 	int gpgsign;
 
 	memset(state, 0, sizeof(*state));
 
-	assert(dir);
-	state->dir = xstrdup(dir);
+	state->dir = git_pathdup("rebase-apply");
 
 	state->prec = 4;
 
@@ -258,38 +261,29 @@ static int read_state_file(struct strbuf *sb, const struct am_state *state,
 }
 
 /**
- * Reads a KEY=VALUE shell variable assignment from `fp`, returning the VALUE
- * as a newly-allocated string. VALUE must be a quoted string, and the KEY must
- * match `key`. Returns NULL on failure.
- *
- * This is used by read_author_script() to read the GIT_AUTHOR_* variables from
- * the author-script.
+ * Take a series of KEY='VALUE' lines where VALUE part is
+ * sq-quoted, and append <KEY, VALUE> at the end of the string list
  */
-static char *read_shell_var(FILE *fp, const char *key)
+static int parse_key_value_squoted(char *buf, struct string_list *list)
 {
-	struct strbuf sb = STRBUF_INIT;
-	const char *str;
-
-	if (strbuf_getline_lf(&sb, fp))
-		goto fail;
-
-	if (!skip_prefix(sb.buf, key, &str))
-		goto fail;
-
-	if (!skip_prefix(str, "=", &str))
-		goto fail;
-
-	strbuf_remove(&sb, 0, str - sb.buf);
-
-	str = sq_dequote(sb.buf);
-	if (!str)
-		goto fail;
-
-	return strbuf_detach(&sb, NULL);
-
-fail:
-	strbuf_release(&sb);
-	return NULL;
+	while (*buf) {
+		struct string_list_item *item;
+		char *np;
+		char *cp = strchr(buf, '=');
+		if (!cp)
+			return -1;
+		np = strchrnul(cp, '\n');
+		*cp++ = '\0';
+		item = string_list_append(list, buf);
+
+		buf = np + (*np == '\n');
+		*np = '\0';
+		cp = sq_dequote(cp);
+		if (!cp)
+			return -1;
+		item->util = xstrdup(cp);
+	}
+	return 0;
 }
 
 /**
@@ -311,44 +305,39 @@ fail:
 static int read_author_script(struct am_state *state)
 {
 	const char *filename = am_path(state, "author-script");
-	FILE *fp;
+	struct strbuf buf = STRBUF_INIT;
+	struct string_list kv = STRING_LIST_INIT_DUP;
+	int retval = -1; /* assume failure */
+	int fd;
 
 	assert(!state->author_name);
 	assert(!state->author_email);
 	assert(!state->author_date);
 
-	fp = fopen(filename, "r");
-	if (!fp) {
+	fd = open(filename, O_RDONLY);
+	if (fd < 0) {
 		if (errno == ENOENT)
 			return 0;
 		die_errno(_("could not open '%s' for reading"), filename);
 	}
+	strbuf_read(&buf, fd, 0);
+	close(fd);
+	if (parse_key_value_squoted(buf.buf, &kv))
+		goto finish;
 
-	state->author_name = read_shell_var(fp, "GIT_AUTHOR_NAME");
-	if (!state->author_name) {
-		fclose(fp);
-		return -1;
-	}
-
-	state->author_email = read_shell_var(fp, "GIT_AUTHOR_EMAIL");
-	if (!state->author_email) {
-		fclose(fp);
-		return -1;
-	}
-
-	state->author_date = read_shell_var(fp, "GIT_AUTHOR_DATE");
-	if (!state->author_date) {
-		fclose(fp);
-		return -1;
-	}
-
-	if (fgetc(fp) != EOF) {
-		fclose(fp);
-		return -1;
-	}
-
-	fclose(fp);
-	return 0;
+	if (kv.nr != 3 ||
+	    strcmp(kv.items[0].string, "GIT_AUTHOR_NAME") ||
+	    strcmp(kv.items[1].string, "GIT_AUTHOR_EMAIL") ||
+	    strcmp(kv.items[2].string, "GIT_AUTHOR_DATE"))
+		goto finish;
+	state->author_name = kv.items[0].util;
+	state->author_email = kv.items[1].util;
+	state->author_date = kv.items[2].util;
+	retval = 0;
+finish:
+	string_list_clear(&kv, !!retval);
+	strbuf_release(&buf);
+	return retval;
 }
 
 /**
@@ -415,11 +404,11 @@ static void am_load(struct am_state *state)
 	struct strbuf sb = STRBUF_INIT;
 
 	if (read_state_file(&sb, state, "next", 1) < 0)
-		die("BUG: state file 'next' does not exist");
+		BUG("state file 'next' does not exist");
 	state->cur = strtol(sb.buf, NULL, 10);
 
 	if (read_state_file(&sb, state, "last", 1) < 0)
-		die("BUG: state file 'last' does not exist");
+		BUG("state file 'last' does not exist");
 	state->last = strtol(sb.buf, NULL, 10);
 
 	if (read_author_script(state) < 0)
@@ -428,8 +417,8 @@ static void am_load(struct am_state *state)
 	read_commit_msg(state);
 
 	if (read_state_file(&sb, state, "original-commit", 1) < 0)
-		hashclr(state->orig_commit);
-	else if (get_sha1_hex(sb.buf, state->orig_commit) < 0)
+		oidclr(&state->orig_commit);
+	else if (get_oid_hex(sb.buf, &state->orig_commit) < 0)
 		die(_("could not parse %s"), am_path(state, "original-commit"));
 
 	read_state_file(&sb, state, "threeway", 1);
@@ -444,6 +433,14 @@ static void am_load(struct am_state *state)
 	read_state_file(&sb, state, "utf8", 1);
 	state->utf8 = !strcmp(sb.buf, "t");
 
+	if (file_exists(am_path(state, "rerere-autoupdate"))) {
+		read_state_file(&sb, state, "rerere-autoupdate", 1);
+		state->allow_rerere_autoupdate = strcmp(sb.buf, "t") ?
+			RERERE_NOAUTOUPDATE : RERERE_AUTOUPDATE;
+	} else {
+		state->allow_rerere_autoupdate = 0;
+	}
+
 	read_state_file(&sb, state, "keep", 1);
 	if (!strcmp(sb.buf, "t"))
 		state->keep = KEEP_TRUE;
@@ -497,8 +494,7 @@ static int run_applypatch_msg_hook(struct am_state *state)
 	ret = run_hook_le(NULL, "applypatch-msg", am_path(state, "final-commit"), NULL);
 
 	if (!ret) {
-		free(state->msg);
-		state->msg = NULL;
+		FREE_AND_NULL(state->msg);
 		if (read_commit_msg(state) < 0)
 			die(_("'%s' was deleted by the applypatch-msg hook"),
 				am_path(state, "final-commit"));
@@ -555,14 +551,14 @@ static int copy_notes_for_rebase(const struct am_state *state)
 	fp = xfopen(am_path(state, "rewritten"), "r");
 
 	while (!strbuf_getline_lf(&sb, fp)) {
-		unsigned char from_obj[GIT_SHA1_RAWSZ], to_obj[GIT_SHA1_RAWSZ];
+		struct object_id from_obj, to_obj;
 
 		if (sb.len != GIT_SHA1_HEXSZ * 2 + 1) {
 			ret = error(invalid_line, sb.buf);
 			goto finish;
 		}
 
-		if (get_sha1_hex(sb.buf, from_obj)) {
+		if (get_oid_hex(sb.buf, &from_obj)) {
 			ret = error(invalid_line, sb.buf);
 			goto finish;
 		}
@@ -572,14 +568,14 @@ static int copy_notes_for_rebase(const struct am_state *state)
 			goto finish;
 		}
 
-		if (get_sha1_hex(sb.buf + GIT_SHA1_HEXSZ + 1, to_obj)) {
+		if (get_oid_hex(sb.buf + GIT_SHA1_HEXSZ + 1, &to_obj)) {
 			ret = error(invalid_line, sb.buf);
 			goto finish;
 		}
 
-		if (copy_note_for_rewrite(c, from_obj, to_obj))
+		if (copy_note_for_rewrite(c, &from_obj, &to_obj))
 			ret = error(_("Failed to copy notes from '%s' to '%s'"),
-					sha1_to_hex(from_obj), sha1_to_hex(to_obj));
+					oid_to_hex(&from_obj), oid_to_hex(&to_obj));
 	}
 
 finish:
@@ -676,9 +672,7 @@ static int detect_patch_format(const char **paths)
 		goto done;
 	}
 
-	strbuf_reset(&l2);
 	strbuf_getline(&l2, fp);
-	strbuf_reset(&l3);
 	strbuf_getline(&l3, fp);
 
 	/*
@@ -701,6 +695,8 @@ static int detect_patch_format(const char **paths)
 done:
 	fclose(fp);
 	strbuf_release(&l1);
+	strbuf_release(&l2);
+	strbuf_release(&l3);
 	return ret;
 }
 
@@ -713,6 +709,7 @@ static int split_mail_mbox(struct am_state *state, const char **paths,
 {
 	struct child_process cp = CHILD_PROCESS_INIT;
 	struct strbuf last = STRBUF_INIT;
+	int ret;
 
 	cp.git_cmd = 1;
 	argv_array_push(&cp.args, "mailsplit");
@@ -726,13 +723,16 @@ static int split_mail_mbox(struct am_state *state, const char **paths,
 	argv_array_push(&cp.args, "--");
 	argv_array_pushv(&cp.args, paths);
 
-	if (capture_command(&cp, &last, 8))
-		return -1;
+	ret = capture_command(&cp, &last, 8);
+	if (ret)
+		goto exit;
 
 	state->cur = 1;
 	state->last = strtol(last.buf, NULL, 10);
 
-	return 0;
+exit:
+	strbuf_release(&last);
+	return ret ? -1 : 0;
 }
 
 /**
@@ -774,14 +774,18 @@ static int split_mail_conv(mail_conv_fn fn, struct am_state *state,
 		mail = mkpath("%s/%0*d", state->dir, state->prec, i + 1);
 
 		out = fopen(mail, "w");
-		if (!out)
+		if (!out) {
+			if (in != stdin)
+				fclose(in);
 			return error_errno(_("could not open '%s' for writing"),
 					   mail);
+		}
 
 		ret = fn(out, in, keep_cr);
 
 		fclose(out);
-		fclose(in);
+		if (in != stdin)
+			fclose(in);
 
 		if (ret)
 			return error(_("could not parse patch '%s'"), *paths);
@@ -882,6 +886,7 @@ static int split_mail_stgit_series(struct am_state *state, const char **paths,
 static int hg_patch_to_mail(FILE *out, FILE *in, int keep_cr)
 {
 	struct strbuf sb = STRBUF_INIT;
+	int rc = 0;
 
 	while (!strbuf_getline_lf(&sb, in)) {
 		const char *str;
@@ -889,25 +894,33 @@ static int hg_patch_to_mail(FILE *out, FILE *in, int keep_cr)
 		if (skip_prefix(sb.buf, "# User ", &str))
 			fprintf(out, "From: %s\n", str);
 		else if (skip_prefix(sb.buf, "# Date ", &str)) {
-			unsigned long timestamp;
+			timestamp_t timestamp;
 			long tz, tz2;
 			char *end;
 
 			errno = 0;
-			timestamp = strtoul(str, &end, 10);
-			if (errno)
-				return error(_("invalid timestamp"));
+			timestamp = parse_timestamp(str, &end, 10);
+			if (errno) {
+				rc = error(_("invalid timestamp"));
+				goto exit;
+			}
 
-			if (!skip_prefix(end, " ", &str))
-				return error(_("invalid Date line"));
+			if (!skip_prefix(end, " ", &str)) {
+				rc = error(_("invalid Date line"));
+				goto exit;
+			}
 
 			errno = 0;
 			tz = strtol(str, &end, 10);
-			if (errno)
-				return error(_("invalid timezone offset"));
+			if (errno) {
+				rc = error(_("invalid timezone offset"));
+				goto exit;
+			}
 
-			if (*end)
-				return error(_("invalid Date line"));
+			if (*end) {
+				rc = error(_("invalid Date line"));
+				goto exit;
+			}
 
 			/*
 			 * mercurial's timezone is in seconds west of UTC,
@@ -932,9 +945,9 @@ static int hg_patch_to_mail(FILE *out, FILE *in, int keep_cr)
 		fwrite(sb.buf, 1, sb.len, out);
 		strbuf_reset(&sb);
 	}
-
+exit:
 	strbuf_release(&sb);
-	return 0;
+	return rc;
 }
 
 /**
@@ -974,7 +987,7 @@ static int split_mail(struct am_state *state, enum patch_format patch_format,
 	case PATCH_FORMAT_MBOXRD:
 		return split_mail_mbox(state, paths, keep_cr, 1);
 	default:
-		die("BUG: invalid patch_format");
+		BUG("invalid patch_format");
 	}
 	return -1;
 }
@@ -985,7 +998,7 @@ static int split_mail(struct am_state *state, enum patch_format patch_format,
 static void am_setup(struct am_state *state, enum patch_format patch_format,
 			const char **paths, int keep_cr)
 {
-	unsigned char curr_head[GIT_SHA1_RAWSZ];
+	struct object_id curr_head;
 	const char *str;
 	struct strbuf sb = STRBUF_INIT;
 
@@ -999,6 +1012,7 @@ static void am_setup(struct am_state *state, enum patch_format patch_format,
 
 	if (mkdir(state->dir, 0777) < 0 && errno != EEXIST)
 		die_errno(_("failed to create directory '%s'"), state->dir);
+	delete_ref(NULL, "REBASE_HEAD", NULL, REF_NO_DEREF);
 
 	if (split_mail(state, patch_format, paths, keep_cr) < 0) {
 		am_destroy(state);
@@ -1013,6 +1027,10 @@ static void am_setup(struct am_state *state, enum patch_format patch_format,
 	write_state_bool(state, "sign", state->signoff);
 	write_state_bool(state, "utf8", state->utf8);
 
+	if (state->allow_rerere_autoupdate)
+		write_state_bool(state, "rerere-autoupdate",
+			 state->allow_rerere_autoupdate == RERERE_AUTOUPDATE);
+
 	switch (state->keep) {
 	case KEEP_FALSE:
 		str = "f";
@@ -1024,7 +1042,7 @@ static void am_setup(struct am_state *state, enum patch_format patch_format,
 		str = "b";
 		break;
 	default:
-		die("BUG: invalid value for state->keep");
+		BUG("invalid value for state->keep");
 	}
 
 	write_state_text(state, "keep", str);
@@ -1041,11 +1059,11 @@ static void am_setup(struct am_state *state, enum patch_format patch_format,
 		str = "t";
 		break;
 	default:
-		die("BUG: invalid value for state->scissors");
+		BUG("invalid value for state->scissors");
 	}
 	write_state_text(state, "scissors", str);
 
-	sq_quote_argv(&sb, state->git_apply_opts.argv, 0);
+	sq_quote_argv(&sb, state->git_apply_opts.argv);
 	write_state_text(state, "apply-opt", sb.buf);
 
 	if (state->rebasing)
@@ -1053,15 +1071,15 @@ static void am_setup(struct am_state *state, enum patch_format patch_format,
 	else
 		write_state_text(state, "applying", "");
 
-	if (!get_sha1("HEAD", curr_head)) {
-		write_state_text(state, "abort-safety", sha1_to_hex(curr_head));
+	if (!get_oid("HEAD", &curr_head)) {
+		write_state_text(state, "abort-safety", oid_to_hex(&curr_head));
 		if (!state->rebasing)
-			update_ref("am", "ORIG_HEAD", curr_head, NULL, 0,
-					UPDATE_REFS_DIE_ON_ERR);
+			update_ref("am", "ORIG_HEAD", &curr_head, NULL, 0,
+				   UPDATE_REFS_DIE_ON_ERR);
 	} else {
 		write_state_text(state, "abort-safety", "");
 		if (!state->rebasing)
-			delete_ref("ORIG_HEAD", NULL, 0);
+			delete_ref(NULL, "ORIG_HEAD", NULL, 0);
 	}
 
 	/*
@@ -1081,29 +1099,23 @@ static void am_setup(struct am_state *state, enum patch_format patch_format,
  */
 static void am_next(struct am_state *state)
 {
-	unsigned char head[GIT_SHA1_RAWSZ];
-
-	free(state->author_name);
-	state->author_name = NULL;
-
-	free(state->author_email);
-	state->author_email = NULL;
-
-	free(state->author_date);
-	state->author_date = NULL;
+	struct object_id head;
 
-	free(state->msg);
-	state->msg = NULL;
+	FREE_AND_NULL(state->author_name);
+	FREE_AND_NULL(state->author_email);
+	FREE_AND_NULL(state->author_date);
+	FREE_AND_NULL(state->msg);
 	state->msg_len = 0;
 
 	unlink(am_path(state, "author-script"));
 	unlink(am_path(state, "final-commit"));
 
-	hashclr(state->orig_commit);
+	oidclr(&state->orig_commit);
 	unlink(am_path(state, "original-commit"));
+	delete_ref(NULL, "REBASE_HEAD", NULL, REF_NO_DEREF);
 
-	if (!get_sha1("HEAD", head))
-		write_state_text(state, "abort-safety", sha1_to_hex(head));
+	if (!get_oid("HEAD", &head))
+		write_state_text(state, "abort-safety", oid_to_hex(&head));
 	else
 		write_state_text(state, "abort-safety", "");
 
@@ -1129,52 +1141,15 @@ static const char *msgnum(const struct am_state *state)
  */
 static void refresh_and_write_cache(void)
 {
-	struct lock_file *lock_file = xcalloc(1, sizeof(struct lock_file));
+	struct lock_file lock_file = LOCK_INIT;
 
-	hold_locked_index(lock_file, 1);
+	hold_locked_index(&lock_file, LOCK_DIE_ON_ERROR);
 	refresh_cache(REFRESH_QUIET);
-	if (write_locked_index(&the_index, lock_file, COMMIT_LOCK))
+	if (write_locked_index(&the_index, &lock_file, COMMIT_LOCK))
 		die(_("unable to write index file"));
 }
 
 /**
- * Returns 1 if the index differs from HEAD, 0 otherwise. When on an unborn
- * branch, returns 1 if there are entries in the index, 0 otherwise. If an
- * strbuf is provided, the space-separated list of files that differ will be
- * appended to it.
- */
-static int index_has_changes(struct strbuf *sb)
-{
-	unsigned char head[GIT_SHA1_RAWSZ];
-	int i;
-
-	if (!get_sha1_tree("HEAD", head)) {
-		struct diff_options opt;
-
-		diff_setup(&opt);
-		DIFF_OPT_SET(&opt, EXIT_WITH_STATUS);
-		if (!sb)
-			DIFF_OPT_SET(&opt, QUICK);
-		do_diff_cache(head, &opt);
-		diffcore_std(&opt);
-		for (i = 0; sb && i < diff_queued_diff.nr; i++) {
-			if (i)
-				strbuf_addch(sb, ' ');
-			strbuf_addstr(sb, diff_queued_diff.queue[i]->two->path);
-		}
-		diff_flush(&opt);
-		return DIFF_OPT_TST(&opt, HAS_CHANGES) != 0;
-	} else {
-		for (i = 0; sb && i < active_nr; i++) {
-			if (i)
-				strbuf_addch(sb, ' ');
-			strbuf_addstr(sb, active_cache[i]->name);
-		}
-		return !!active_nr;
-	}
-}
-
-/**
  * Dies with a user-friendly message on how to proceed after resolving the
  * problem. This message can be overridden with state->resolvemsg.
  */
@@ -1193,33 +1168,6 @@ static void NORETURN die_user_resolve(const struct am_state *state)
 	exit(128);
 }
 
-static void am_signoff(struct strbuf *sb)
-{
-	char *cp;
-	struct strbuf mine = STRBUF_INIT;
-
-	/* Does it end with our own sign-off? */
-	strbuf_addf(&mine, "\n%s%s\n",
-		    sign_off_header,
-		    fmt_name(getenv("GIT_COMMITTER_NAME"),
-			     getenv("GIT_COMMITTER_EMAIL")));
-	if (mine.len < sb->len &&
-	    !strcmp(mine.buf, sb->buf + sb->len - mine.len))
-		goto exit; /* no need to duplicate */
-
-	/* Does it have any Signed-off-by: in the text */
-	for (cp = sb->buf;
-	     cp && *cp && (cp = strstr(cp, sign_off_header)) != NULL;
-	     cp = strchr(cp, '\n')) {
-		if (sb->buf == cp || cp[-1] == '\n')
-			break;
-	}
-
-	strbuf_addstr(sb, mine.buf + !!cp);
-exit:
-	strbuf_release(&mine);
-}
-
 /**
  * Appends signoff to the "msg" field of the am_state.
  */
@@ -1228,7 +1176,7 @@ static void am_append_signoff(struct am_state *state)
 	struct strbuf sb = STRBUF_INIT;
 
 	strbuf_attach(&sb, state->msg, state->msg_len, state->msg_len);
-	am_signoff(&sb);
+	append_signoff(&sb, 0, 0);
 	state->msg = strbuf_detach(&sb, &state->msg_len);
 }
 
@@ -1269,7 +1217,7 @@ static int parse_mail(struct am_state *state, const char *mail)
 		mi.keep_non_patch_brackets_in_subject = 1;
 		break;
 	default:
-		die("BUG: invalid value for state->keep");
+		BUG("invalid value for state->keep");
 	}
 
 	if (state->message_id)
@@ -1285,21 +1233,21 @@ static int parse_mail(struct am_state *state, const char *mail)
 		mi.use_scissors = 1;
 		break;
 	default:
-		die("BUG: invalid value for state->scissors");
+		BUG("invalid value for state->scissors");
 	}
 
-	mi.input = fopen(mail, "r");
-	if (!mi.input)
-		die("could not open input");
-	mi.output = fopen(am_path(state, "info"), "w");
-	if (!mi.output)
-		die("could not open output 'info'");
+	mi.input = xfopen(mail, "r");
+	mi.output = xfopen(am_path(state, "info"), "w");
 	if (mailinfo(&mi, am_path(state, "msg"), am_path(state, "patch")))
 		die("could not parse patch");
 
 	fclose(mi.input);
 	fclose(mi.output);
 
+	if (mi.format_flowed)
+		warning(_("Patch sent with format=flowed; "
+			  "space at the end of lines might be lost."));
+
 	/* Extract message and author information */
 	fp = xfopen(am_path(state, "info"), "r");
 	while (!strbuf_getline_lf(&sb, fp)) {
@@ -1325,7 +1273,7 @@ static int parse_mail(struct am_state *state, const char *mail)
 	}
 
 	if (is_empty_file(am_path(state, "patch"))) {
-		printf_ln(_("Patch is empty. Was it split wrong?"));
+		printf_ln(_("Patch is empty."));
 		die_user_resolve(state);
 	}
 
@@ -1333,9 +1281,6 @@ static int parse_mail(struct am_state *state, const char *mail)
 	strbuf_addbuf(&msg, &mi.log_message);
 	strbuf_stripspace(&msg, 0);
 
-	if (state->signoff)
-		am_signoff(&msg);
-
 	assert(!state->author_name);
 	state->author_name = strbuf_detach(&author_name, NULL);
 
@@ -1362,24 +1307,21 @@ finish:
  * Sets commit_id to the commit hash where the mail was generated from.
  * Returns 0 on success, -1 on failure.
  */
-static int get_mail_commit_sha1(unsigned char *commit_id, const char *mail)
+static int get_mail_commit_oid(struct object_id *commit_id, const char *mail)
 {
 	struct strbuf sb = STRBUF_INIT;
 	FILE *fp = xfopen(mail, "r");
 	const char *x;
+	int ret = 0;
 
-	if (strbuf_getline_lf(&sb, fp))
-		return -1;
-
-	if (!skip_prefix(sb.buf, "From ", &x))
-		return -1;
-
-	if (get_sha1_hex(x, commit_id) < 0)
-		return -1;
+	if (strbuf_getline_lf(&sb, fp) ||
+	    !skip_prefix(sb.buf, "From ", &x) ||
+	    get_oid_hex(x, commit_id) < 0)
+		ret = -1;
 
 	strbuf_release(&sb);
 	fclose(fp);
-	return 0;
+	return ret;
 }
 
 /**
@@ -1388,40 +1330,33 @@ static int get_mail_commit_sha1(unsigned char *commit_id, const char *mail)
  */
 static void get_commit_info(struct am_state *state, struct commit *commit)
 {
-	const char *buffer, *ident_line, *author_date, *msg;
+	const char *buffer, *ident_line, *msg;
 	size_t ident_len;
-	struct ident_split ident_split;
-	struct strbuf sb = STRBUF_INIT;
+	struct ident_split id;
 
 	buffer = logmsg_reencode(commit, NULL, get_commit_output_encoding());
 
 	ident_line = find_commit_header(buffer, "author", &ident_len);
 
-	if (split_ident_line(&ident_split, ident_line, ident_len) < 0) {
-		strbuf_add(&sb, ident_line, ident_len);
-		die(_("invalid ident line: %s"), sb.buf);
-	}
+	if (split_ident_line(&id, ident_line, ident_len) < 0)
+		die(_("invalid ident line: %.*s"), (int)ident_len, ident_line);
 
 	assert(!state->author_name);
-	if (ident_split.name_begin) {
-		strbuf_add(&sb, ident_split.name_begin,
-			ident_split.name_end - ident_split.name_begin);
-		state->author_name = strbuf_detach(&sb, NULL);
-	} else
+	if (id.name_begin)
+		state->author_name =
+			xmemdupz(id.name_begin, id.name_end - id.name_begin);
+	else
 		state->author_name = xstrdup("");
 
 	assert(!state->author_email);
-	if (ident_split.mail_begin) {
-		strbuf_add(&sb, ident_split.mail_begin,
-			ident_split.mail_end - ident_split.mail_begin);
-		state->author_email = strbuf_detach(&sb, NULL);
-	} else
+	if (id.mail_begin)
+		state->author_email =
+			xmemdupz(id.mail_begin, id.mail_end - id.mail_begin);
+	else
 		state->author_email = xstrdup("");
 
-	author_date = show_ident_date(&ident_split, DATE_MODE(NORMAL));
-	strbuf_addstr(&sb, author_date);
 	assert(!state->author_date);
-	state->author_date = strbuf_detach(&sb, NULL);
+	state->author_date = xstrdup(show_ident_date(&id, DATE_MODE(NORMAL)));
 
 	assert(!state->msg);
 	msg = strstr(buffer, "\n\n");
@@ -1429,6 +1364,7 @@ static void get_commit_info(struct am_state *state, struct commit *commit)
 		die(_("unable to parse commit %s"), oid_to_hex(&commit->object.oid));
 	state->msg = xstrdup(msg + 2);
 	state->msg_len = strlen(state->msg);
+	unuse_commit_buffer(commit, buffer);
 }
 
 /**
@@ -1447,8 +1383,8 @@ static void write_commit_patch(const struct am_state *state, struct commit *comm
 	rev_info.show_root_diff = 1;
 	rev_info.diffopt.output_format = DIFF_FORMAT_PATCH;
 	rev_info.no_commit_id = 1;
-	DIFF_OPT_SET(&rev_info.diffopt, BINARY);
-	DIFF_OPT_SET(&rev_info.diffopt, FULL_INDEX);
+	rev_info.diffopt.flags.binary = 1;
+	rev_info.diffopt.flags.full_index = 1;
 	rev_info.diffopt.use_color = 0;
 	rev_info.diffopt.file = fp;
 	rev_info.diffopt.close_file = 1;
@@ -1464,14 +1400,15 @@ static void write_commit_patch(const struct am_state *state, struct commit *comm
 static void write_index_patch(const struct am_state *state)
 {
 	struct tree *tree;
-	unsigned char head[GIT_SHA1_RAWSZ];
+	struct object_id head;
 	struct rev_info rev_info;
 	FILE *fp;
 
-	if (!get_sha1_tree("HEAD", head))
-		tree = lookup_tree(head);
+	if (!get_oid_tree("HEAD", &head))
+		tree = lookup_tree(the_repository, &head);
 	else
-		tree = lookup_tree(EMPTY_TREE_SHA1_BIN);
+		tree = lookup_tree(the_repository,
+				   the_repository->hash_algo->empty_tree);
 
 	fp = xfopen(am_path(state, "patch"), "w");
 	init_revisions(&rev_info, NULL);
@@ -1499,19 +1436,21 @@ static void write_index_patch(const struct am_state *state)
 static int parse_mail_rebase(struct am_state *state, const char *mail)
 {
 	struct commit *commit;
-	unsigned char commit_sha1[GIT_SHA1_RAWSZ];
+	struct object_id commit_oid;
 
-	if (get_mail_commit_sha1(commit_sha1, mail) < 0)
+	if (get_mail_commit_oid(&commit_oid, mail) < 0)
 		die(_("could not parse %s"), mail);
 
-	commit = lookup_commit_or_die(commit_sha1, mail);
+	commit = lookup_commit_or_die(&commit_oid, mail);
 
 	get_commit_info(state, commit);
 
 	write_commit_patch(state, commit);
 
-	hashcpy(state->orig_commit, commit_sha1);
-	write_state_text(state, "original-commit", sha1_to_hex(commit_sha1));
+	oidcpy(&state->orig_commit, &commit_oid);
+	write_state_text(state, "original-commit", oid_to_hex(&commit_oid));
+	update_ref("am", "REBASE_HEAD", &commit_oid,
+		   NULL, REF_NO_DEREF, UPDATE_REFS_DIE_ON_ERR);
 
 	return 0;
 }
@@ -1522,39 +1461,58 @@ static int parse_mail_rebase(struct am_state *state, const char *mail)
  */
 static int run_apply(const struct am_state *state, const char *index_file)
 {
-	struct child_process cp = CHILD_PROCESS_INIT;
+	struct argv_array apply_paths = ARGV_ARRAY_INIT;
+	struct argv_array apply_opts = ARGV_ARRAY_INIT;
+	struct apply_state apply_state;
+	int res, opts_left;
+	int force_apply = 0;
+	int options = 0;
 
-	cp.git_cmd = 1;
+	if (init_apply_state(&apply_state, the_repository, NULL))
+		BUG("init_apply_state() failed");
 
-	if (index_file)
-		argv_array_pushf(&cp.env_array, "GIT_INDEX_FILE=%s", index_file);
+	argv_array_push(&apply_opts, "apply");
+	argv_array_pushv(&apply_opts, state->git_apply_opts.argv);
+
+	opts_left = apply_parse_options(apply_opts.argc, apply_opts.argv,
+					&apply_state, &force_apply, &options,
+					NULL);
+
+	if (opts_left != 0)
+		die("unknown option passed through to git apply");
+
+	if (index_file) {
+		apply_state.index_file = index_file;
+		apply_state.cached = 1;
+	} else
+		apply_state.check_index = 1;
 
 	/*
 	 * If we are allowed to fall back on 3-way merge, don't give false
 	 * errors during the initial attempt.
 	 */
-	if (state->threeway && !index_file) {
-		cp.no_stdout = 1;
-		cp.no_stderr = 1;
-	}
+	if (state->threeway && !index_file)
+		apply_state.apply_verbosity = verbosity_silent;
 
-	argv_array_push(&cp.args, "apply");
+	if (check_apply_state(&apply_state, force_apply))
+		BUG("check_apply_state() failed");
 
-	argv_array_pushv(&cp.args, state->git_apply_opts.argv);
+	argv_array_push(&apply_paths, am_path(state, "patch"));
 
-	if (index_file)
-		argv_array_push(&cp.args, "--cached");
-	else
-		argv_array_push(&cp.args, "--index");
+	res = apply_all_patches(&apply_state, apply_paths.argc, apply_paths.argv, options);
 
-	argv_array_push(&cp.args, am_path(state, "patch"));
+	argv_array_clear(&apply_paths);
+	argv_array_clear(&apply_opts);
+	clear_apply_state(&apply_state);
 
-	if (run_command(&cp))
-		return -1;
+	if (res)
+		return res;
 
-	/* Reload index as git-apply will have modified it. */
-	discard_cache();
-	read_cache_from(index_file ? index_file : get_index_file());
+	if (index_file) {
+		/* Reload index as apply_all_patches() will have modified it. */
+		discard_cache();
+		read_cache_from(index_file);
+	}
 
 	return 0;
 }
@@ -1579,47 +1537,18 @@ static int build_fake_ancestor(const struct am_state *state, const char *index_f
 }
 
 /**
- * Do the three-way merge using fake ancestor, their tree constructed
- * from the fake ancestor and the postimage of the patch, and our
- * state.
- */
-static int run_fallback_merge_recursive(const struct am_state *state,
-					unsigned char *orig_tree,
-					unsigned char *our_tree,
-					unsigned char *their_tree)
-{
-	struct child_process cp = CHILD_PROCESS_INIT;
-	int status;
-
-	cp.git_cmd = 1;
-
-	argv_array_pushf(&cp.env_array, "GITHEAD_%s=%.*s",
-			 sha1_to_hex(their_tree), linelen(state->msg), state->msg);
-	if (state->quiet)
-		argv_array_push(&cp.env_array, "GIT_MERGE_VERBOSITY=0");
-
-	argv_array_push(&cp.args, "merge-recursive");
-	argv_array_push(&cp.args, sha1_to_hex(orig_tree));
-	argv_array_push(&cp.args, "--");
-	argv_array_push(&cp.args, sha1_to_hex(our_tree));
-	argv_array_push(&cp.args, sha1_to_hex(their_tree));
-
-	status = run_command(&cp) ? (-1) : 0;
-	discard_cache();
-	read_cache();
-	return status;
-}
-
-/**
  * Attempt a threeway merge, using index_path as the temporary index.
  */
 static int fall_back_threeway(const struct am_state *state, const char *index_path)
 {
-	unsigned char orig_tree[GIT_SHA1_RAWSZ], their_tree[GIT_SHA1_RAWSZ],
-		      our_tree[GIT_SHA1_RAWSZ];
+	struct object_id orig_tree, their_tree, our_tree;
+	const struct object_id *bases[1] = { &orig_tree };
+	struct merge_options o;
+	struct commit *result;
+	char *their_tree_name;
 
-	if (get_sha1("HEAD", our_tree) < 0)
-		hashcpy(our_tree, EMPTY_TREE_SHA1_BIN);
+	if (get_oid("HEAD", &our_tree) < 0)
+		oidcpy(&our_tree, the_hash_algo->empty_tree);
 
 	if (build_fake_ancestor(state, index_path))
 		return error("could not build fake ancestor");
@@ -1627,7 +1556,7 @@ static int fall_back_threeway(const struct am_state *state, const char *index_pa
 	discard_cache();
 	read_cache_from(index_path);
 
-	if (write_index_as_tree(orig_tree, &the_index, index_path, 0, NULL))
+	if (write_index_as_tree(&orig_tree, &the_index, index_path, 0, NULL))
 		return error(_("Repository lacks necessary blobs to fall back on 3-way merge."));
 
 	say(state, stdout, _("Using index info to reconstruct a base tree..."));
@@ -1643,7 +1572,7 @@ static int fall_back_threeway(const struct am_state *state, const char *index_pa
 		init_revisions(&rev_info, NULL);
 		rev_info.diffopt.output_format = DIFF_FORMAT_NAME_STATUS;
 		diff_opt_parse(&rev_info.diffopt, &diff_filter_str, 1, rev_info.prefix);
-		add_pending_sha1(&rev_info, "HEAD", our_tree, 0);
+		add_pending_oid(&rev_info, "HEAD", &our_tree, 0);
 		diff_setup_done(&rev_info.diffopt);
 		run_diff_index(&rev_info, 1);
 	}
@@ -1652,7 +1581,7 @@ static int fall_back_threeway(const struct am_state *state, const char *index_pa
 		return error(_("Did you hand edit your patch?\n"
 				"It does not apply to blobs recorded in its index."));
 
-	if (write_index_as_tree(their_tree, &the_index, index_path, 0, NULL))
+	if (write_index_as_tree(&their_tree, &the_index, index_path, 0, NULL))
 		return error("could not write tree");
 
 	say(state, stdout, _("Falling back to patching base and 3-way merge..."));
@@ -1668,11 +1597,23 @@ static int fall_back_threeway(const struct am_state *state, const char *index_pa
 	 * changes.
 	 */
 
-	if (run_fallback_merge_recursive(state, orig_tree, our_tree, their_tree)) {
+	init_merge_options(&o);
+
+	o.branch1 = "HEAD";
+	their_tree_name = xstrfmt("%.*s", linelen(state->msg), state->msg);
+	o.branch2 = their_tree_name;
+	o.detect_directory_renames = 0;
+
+	if (state->quiet)
+		o.verbosity = 0;
+
+	if (merge_recursive_generic(&o, &our_tree, &their_tree, 1, bases, &result)) {
 		rerere(state->allow_rerere_autoupdate);
+		free(their_tree_name);
 		return error(_("Failed to merge in the changes."));
 	}
 
+	free(their_tree_name);
 	return 0;
 }
 
@@ -1683,9 +1624,8 @@ static int fall_back_threeway(const struct am_state *state, const char *index_pa
  */
 static void do_commit(const struct am_state *state)
 {
-	unsigned char tree[GIT_SHA1_RAWSZ], parent[GIT_SHA1_RAWSZ],
-		      commit[GIT_SHA1_RAWSZ];
-	unsigned char *ptr;
+	struct object_id tree, parent, commit;
+	const struct object_id *old_oid;
 	struct commit_list *parents = NULL;
 	const char *reflog_msg, *author;
 	struct strbuf sb = STRBUF_INIT;
@@ -1693,14 +1633,15 @@ static void do_commit(const struct am_state *state)
 	if (run_hook_le(NULL, "pre-applypatch", NULL))
 		exit(1);
 
-	if (write_cache_as_tree(tree, 0, NULL))
+	if (write_cache_as_tree(&tree, 0, NULL))
 		die(_("git write-tree failed to write a tree"));
 
-	if (!get_sha1_commit("HEAD", parent)) {
-		ptr = parent;
-		commit_list_insert(lookup_commit(parent), &parents);
+	if (!get_oid_commit("HEAD", &parent)) {
+		old_oid = &parent;
+		commit_list_insert(lookup_commit(the_repository, &parent),
+				   &parents);
 	} else {
-		ptr = NULL;
+		old_oid = NULL;
 		say(state, stderr, _("applying to an empty history"));
 	}
 
@@ -1712,8 +1653,8 @@ static void do_commit(const struct am_state *state)
 		setenv("GIT_COMMITTER_DATE",
 			state->ignore_date ? "" : state->author_date, 1);
 
-	if (commit_tree(state->msg, state->msg_len, tree, parents, commit,
-				author, state->sign_commit))
+	if (commit_tree(state->msg, state->msg_len, &tree, parents, &commit,
+			author, state->sign_commit))
 		die(_("failed to write commit object"));
 
 	reflog_msg = getenv("GIT_REFLOG_ACTION");
@@ -1723,14 +1664,15 @@ static void do_commit(const struct am_state *state)
 	strbuf_addf(&sb, "%s: %.*s", reflog_msg, linelen(state->msg),
 			state->msg);
 
-	update_ref(sb.buf, "HEAD", commit, ptr, 0, UPDATE_REFS_DIE_ON_ERR);
+	update_ref(sb.buf, "HEAD", &commit, old_oid, 0,
+		   UPDATE_REFS_DIE_ON_ERR);
 
 	if (state->rebasing) {
 		FILE *fp = xfopen(am_path(state, "rewritten"), "a");
 
-		assert(!is_null_sha1(state->orig_commit));
-		fprintf(fp, "%s ", sha1_to_hex(state->orig_commit));
-		fprintf(fp, "%s\n", sha1_to_hex(commit));
+		assert(!is_null_oid(&state->orig_commit));
+		fprintf(fp, "%s ", oid_to_hex(&state->orig_commit));
+		fprintf(fp, "%s\n", oid_to_hex(&commit));
 		fclose(fp);
 	}
 
@@ -1829,7 +1771,7 @@ static void am_run(struct am_state *state, int resume)
 
 	refresh_and_write_cache();
 
-	if (index_has_changes(&sb)) {
+	if (index_has_changes(&the_index, NULL, &sb)) {
 		write_state_bool(state, "dirtyindex", 1);
 		die(_("Dirty index: cannot apply patches (dirty: %s)"), sb.buf);
 	}
@@ -1840,6 +1782,8 @@ static void am_run(struct am_state *state, int resume)
 		const char *mail = am_path(state, msgnum(state));
 		int apply_status;
 
+		reset_ident_date();
+
 		if (!file_exists(mail))
 			goto next;
 
@@ -1856,6 +1800,9 @@ static void am_run(struct am_state *state, int resume)
 			if (skip)
 				goto next; /* mail should be skipped */
 
+			if (state->signoff)
+				am_append_signoff(state);
+
 			write_author_script(state);
 			write_commit_msg(state);
 		}
@@ -1881,23 +1828,19 @@ static void am_run(struct am_state *state, int resume)
 			 * Applying the patch to an earlier tree and merging
 			 * the result may have produced the same tree as ours.
 			 */
-			if (!apply_status && !index_has_changes(NULL)) {
+			if (!apply_status &&
+			    !index_has_changes(&the_index, NULL, NULL)) {
 				say(state, stdout, _("No changes -- Patch already applied."));
 				goto next;
 			}
 		}
 
 		if (apply_status) {
-			int advice_amworkdir = 1;
-
 			printf_ln(_("Patch failed at %s %.*s"), msgnum(state),
 				linelen(state->msg), state->msg);
 
-			git_config_get_bool("advice.amworkdir", &advice_amworkdir);
-
 			if (advice_amworkdir)
-				printf_ln(_("The copy of the patch that failed is found in: %s"),
-						am_path(state, "patch"));
+				advise(_("Use 'git am --show-current-patch' to see the failed patch"));
 
 			die_user_resolve(state);
 		}
@@ -1924,7 +1867,7 @@ next:
 	 */
 	if (!state->rebasing) {
 		am_destroy(state);
-		close_all_packs();
+		close_all_packs(the_repository->objects);
 		run_command_v_opt(argv_gc_auto, RUN_GIT_CMD);
 	}
 }
@@ -1940,7 +1883,7 @@ static void am_resolve(struct am_state *state)
 
 	say(state, stdout, _("Applying: %.*s"), linelen(state->msg), state->msg);
 
-	if (!index_has_changes(NULL)) {
+	if (!index_has_changes(&the_index, NULL, NULL)) {
 		printf_ln(_("No changes - did you forget to use 'git add'?\n"
 			"If there is nothing left to stage, chances are that something else\n"
 			"already introduced the same changes; you might want to skip this patch."));
@@ -1949,7 +1892,8 @@ static void am_resolve(struct am_state *state)
 
 	if (unmerged_cache()) {
 		printf_ln(_("You still have unmerged paths in your index.\n"
-			"Did you forget to use 'git add'?"));
+			"You should 'git add' each file with resolved conflicts to mark them as such.\n"
+			"You might run `git rm` on a file to accept \"deleted by them\" for it."));
 		die_user_resolve(state);
 	}
 
@@ -1976,15 +1920,14 @@ next:
  */
 static int fast_forward_to(struct tree *head, struct tree *remote, int reset)
 {
-	struct lock_file *lock_file;
+	struct lock_file lock_file = LOCK_INIT;
 	struct unpack_trees_options opts;
 	struct tree_desc t[2];
 
 	if (parse_tree(head) || parse_tree(remote))
 		return -1;
 
-	lock_file = xcalloc(1, sizeof(struct lock_file));
-	hold_locked_index(lock_file, 1);
+	hold_locked_index(&lock_file, LOCK_DIE_ON_ERROR);
 
 	refresh_cache(REFRESH_QUIET);
 
@@ -2000,11 +1943,11 @@ static int fast_forward_to(struct tree *head, struct tree *remote, int reset)
 	init_tree_desc(&t[1], remote->buffer, remote->size);
 
 	if (unpack_trees(2, t, &opts)) {
-		rollback_lock_file(lock_file);
+		rollback_lock_file(&lock_file);
 		return -1;
 	}
 
-	if (write_locked_index(&the_index, lock_file, COMMIT_LOCK))
+	if (write_locked_index(&the_index, &lock_file, COMMIT_LOCK))
 		die(_("unable to write new index file"));
 
 	return 0;
@@ -2016,15 +1959,14 @@ static int fast_forward_to(struct tree *head, struct tree *remote, int reset)
  */
 static int merge_tree(struct tree *tree)
 {
-	struct lock_file *lock_file;
+	struct lock_file lock_file = LOCK_INIT;
 	struct unpack_trees_options opts;
 	struct tree_desc t[1];
 
 	if (parse_tree(tree))
 		return -1;
 
-	lock_file = xcalloc(1, sizeof(struct lock_file));
-	hold_locked_index(lock_file, 1);
+	hold_locked_index(&lock_file, LOCK_DIE_ON_ERROR);
 
 	memset(&opts, 0, sizeof(opts));
 	opts.head_idx = 1;
@@ -2035,11 +1977,11 @@ static int merge_tree(struct tree *tree)
 	init_tree_desc(&t[0], tree->buffer, tree->size);
 
 	if (unpack_trees(1, t, &opts)) {
-		rollback_lock_file(lock_file);
+		rollback_lock_file(&lock_file);
 		return -1;
 	}
 
-	if (write_locked_index(&the_index, lock_file, COMMIT_LOCK))
+	if (write_locked_index(&the_index, &lock_file, COMMIT_LOCK))
 		die(_("unable to write new index file"));
 
 	return 0;
@@ -2049,30 +1991,30 @@ static int merge_tree(struct tree *tree)
  * Clean the index without touching entries that are not modified between
  * `head` and `remote`.
  */
-static int clean_index(const unsigned char *head, const unsigned char *remote)
+static int clean_index(const struct object_id *head, const struct object_id *remote)
 {
 	struct tree *head_tree, *remote_tree, *index_tree;
-	unsigned char index[GIT_SHA1_RAWSZ];
+	struct object_id index;
 
 	head_tree = parse_tree_indirect(head);
 	if (!head_tree)
-		return error(_("Could not parse object '%s'."), sha1_to_hex(head));
+		return error(_("Could not parse object '%s'."), oid_to_hex(head));
 
 	remote_tree = parse_tree_indirect(remote);
 	if (!remote_tree)
-		return error(_("Could not parse object '%s'."), sha1_to_hex(remote));
+		return error(_("Could not parse object '%s'."), oid_to_hex(remote));
 
 	read_cache_unmerged();
 
 	if (fast_forward_to(head_tree, head_tree, 1))
 		return -1;
 
-	if (write_cache_as_tree(index, 0, NULL))
+	if (write_cache_as_tree(&index, 0, NULL))
 		return -1;
 
-	index_tree = parse_tree_indirect(index);
+	index_tree = parse_tree_indirect(&index);
 	if (!index_tree)
-		return error(_("Could not parse object '%s'."), sha1_to_hex(index));
+		return error(_("Could not parse object '%s'."), oid_to_hex(&index));
 
 	if (fast_forward_to(index_tree, remote_tree, 0))
 		return -1;
@@ -2100,14 +2042,14 @@ static void am_rerere_clear(void)
  */
 static void am_skip(struct am_state *state)
 {
-	unsigned char head[GIT_SHA1_RAWSZ];
+	struct object_id head;
 
 	am_rerere_clear();
 
-	if (get_sha1("HEAD", head))
-		hashcpy(head, EMPTY_TREE_SHA1_BIN);
+	if (get_oid("HEAD", &head))
+		oidcpy(&head, the_hash_algo->empty_tree);
 
-	if (clean_index(head, head))
+	if (clean_index(&head, &head))
 		die(_("failed to clean index"));
 
 	am_next(state);
@@ -2125,24 +2067,25 @@ static void am_skip(struct am_state *state)
 static int safe_to_abort(const struct am_state *state)
 {
 	struct strbuf sb = STRBUF_INIT;
-	unsigned char abort_safety[GIT_SHA1_RAWSZ], head[GIT_SHA1_RAWSZ];
+	struct object_id abort_safety, head;
 
 	if (file_exists(am_path(state, "dirtyindex")))
 		return 0;
 
 	if (read_state_file(&sb, state, "abort-safety", 1) > 0) {
-		if (get_sha1_hex(sb.buf, abort_safety))
-			die(_("could not parse %s"), am_path(state, "abort_safety"));
+		if (get_oid_hex(sb.buf, &abort_safety))
+			die(_("could not parse %s"), am_path(state, "abort-safety"));
 	} else
-		hashclr(abort_safety);
+		oidclr(&abort_safety);
+	strbuf_release(&sb);
 
-	if (get_sha1("HEAD", head))
-		hashclr(head);
+	if (get_oid("HEAD", &head))
+		oidclr(&head);
 
-	if (!hashcmp(head, abort_safety))
+	if (oideq(&head, &abort_safety))
 		return 1;
 
-	error(_("You seem to have moved HEAD since the last 'am' failure.\n"
+	warning(_("You seem to have moved HEAD since the last 'am' failure.\n"
 		"Not rewinding to ORIG_HEAD"));
 
 	return 0;
@@ -2153,7 +2096,7 @@ static int safe_to_abort(const struct am_state *state)
  */
 static void am_abort(struct am_state *state)
 {
-	unsigned char curr_head[GIT_SHA1_RAWSZ], orig_head[GIT_SHA1_RAWSZ];
+	struct object_id curr_head, orig_head;
 	int has_curr_head, has_orig_head;
 	char *curr_branch;
 
@@ -2164,28 +2107,56 @@ static void am_abort(struct am_state *state)
 
 	am_rerere_clear();
 
-	curr_branch = resolve_refdup("HEAD", 0, curr_head, NULL);
-	has_curr_head = !is_null_sha1(curr_head);
+	curr_branch = resolve_refdup("HEAD", 0, &curr_head, NULL);
+	has_curr_head = curr_branch && !is_null_oid(&curr_head);
 	if (!has_curr_head)
-		hashcpy(curr_head, EMPTY_TREE_SHA1_BIN);
+		oidcpy(&curr_head, the_hash_algo->empty_tree);
 
-	has_orig_head = !get_sha1("ORIG_HEAD", orig_head);
+	has_orig_head = !get_oid("ORIG_HEAD", &orig_head);
 	if (!has_orig_head)
-		hashcpy(orig_head, EMPTY_TREE_SHA1_BIN);
+		oidcpy(&orig_head, the_hash_algo->empty_tree);
 
-	clean_index(curr_head, orig_head);
+	clean_index(&curr_head, &orig_head);
 
 	if (has_orig_head)
-		update_ref("am --abort", "HEAD", orig_head,
-				has_curr_head ? curr_head : NULL, 0,
-				UPDATE_REFS_DIE_ON_ERR);
+		update_ref("am --abort", "HEAD", &orig_head,
+			   has_curr_head ? &curr_head : NULL, 0,
+			   UPDATE_REFS_DIE_ON_ERR);
 	else if (curr_branch)
-		delete_ref(curr_branch, NULL, REF_NODEREF);
+		delete_ref(NULL, curr_branch, NULL, REF_NO_DEREF);
 
 	free(curr_branch);
 	am_destroy(state);
 }
 
+static int show_patch(struct am_state *state)
+{
+	struct strbuf sb = STRBUF_INIT;
+	const char *patch_path;
+	int len;
+
+	if (!is_null_oid(&state->orig_commit)) {
+		const char *av[4] = { "show", NULL, "--", NULL };
+		char *new_oid_str;
+		int ret;
+
+		av[1] = new_oid_str = xstrdup(oid_to_hex(&state->orig_commit));
+		ret = run_command_v_opt(av, RUN_GIT_CMD);
+		free(new_oid_str);
+		return ret;
+	}
+
+	patch_path = am_path(state, msgnum(state));
+	len = strbuf_read_file(&sb, patch_path, 0);
+	if (len < 0)
+		die_errno(_("failed to read '%s'"), patch_path);
+
+	setup_pager();
+	write_in_full(1, sb.buf, sb.len);
+	strbuf_release(&sb);
+	return 0;
+}
+
 /**
  * parse_options() callback that validates and sets opt->value to the
  * PATCH_FORMAT_* enum value corresponding to `arg`.
@@ -2214,7 +2185,9 @@ enum resume_mode {
 	RESUME_APPLY,
 	RESUME_RESOLVED,
 	RESUME_SKIP,
-	RESUME_ABORT
+	RESUME_ABORT,
+	RESUME_QUIT,
+	RESUME_SHOW_PATCH
 };
 
 static int git_am_config(const char *k, const char *v, void *cb)
@@ -2236,9 +2209,10 @@ int cmd_am(int argc, const char **argv, const char *prefix)
 	int patch_format = PATCH_FORMAT_UNKNOWN;
 	enum resume_mode resume = RESUME_FALSE;
 	int in_progress;
+	int ret = 0;
 
 	const char * const usage[] = {
-		N_("git am [<options>] [(<mbox>|<Maildir>)...]"),
+		N_("git am [<options>] [(<mbox> | <Maildir>)...]"),
 		N_("git am [<options>] (--continue | --skip | --abort)"),
 		NULL
 	};
@@ -2262,12 +2236,12 @@ int cmd_am(int argc, const char **argv, const char *prefix)
 			N_("pass -b flag to git-mailinfo"), KEEP_NON_PATCH),
 		OPT_BOOL('m', "message-id", &state.message_id,
 			N_("pass -m flag to git-mailinfo")),
-		{ OPTION_SET_INT, 0, "keep-cr", &keep_cr, NULL,
-		  N_("pass --keep-cr flag to git-mailsplit for mbox format"),
-		  PARSE_OPT_NOARG | PARSE_OPT_NONEG, NULL, 1},
-		{ OPTION_SET_INT, 0, "no-keep-cr", &keep_cr, NULL,
-		  N_("do not pass --keep-cr flag to git-mailsplit independent of am.keepcr"),
-		  PARSE_OPT_NOARG | PARSE_OPT_NONEG, NULL, 0},
+		OPT_SET_INT_F(0, "keep-cr", &keep_cr,
+			N_("pass --keep-cr flag to git-mailsplit for mbox format"),
+			1, PARSE_OPT_NONEG),
+		OPT_SET_INT_F(0, "no-keep-cr", &keep_cr,
+			N_("do not pass --keep-cr flag to git-mailsplit independent of am.keepcr"),
+			0, PARSE_OPT_NONEG),
 		OPT_BOOL('c', "scissors", &state.scissors,
 			N_("strip everything before a scissors line")),
 		OPT_PASSTHRU_ARGV(0, "whitespace", &state.git_apply_opts, N_("action"),
@@ -2314,6 +2288,12 @@ int cmd_am(int argc, const char **argv, const char *prefix)
 		OPT_CMDMODE(0, "abort", &resume,
 			N_("restore the original branch and abort the patching operation."),
 			RESUME_ABORT),
+		OPT_CMDMODE(0, "quit", &resume,
+			N_("abort the patching operation but keep HEAD where it is."),
+			RESUME_QUIT),
+		OPT_CMDMODE(0, "show-current-patch", &resume,
+			N_("show the patch being applied."),
+			RESUME_SHOW_PATCH),
 		OPT_BOOL(0, "committer-date-is-author-date",
 			&state.committer_date_is_author_date,
 			N_("lie about committer date")),
@@ -2328,9 +2308,12 @@ int cmd_am(int argc, const char **argv, const char *prefix)
 		OPT_END()
 	};
 
+	if (argc == 2 && !strcmp(argv[1], "-h"))
+		usage_with_options(usage, options);
+
 	git_config(git_am_config, NULL);
 
-	am_state_init(&state, git_path("rebase-apply"));
+	am_state_init(&state);
 
 	in_progress = am_in_progress(&state);
 	if (in_progress)
@@ -2379,7 +2362,7 @@ int cmd_am(int argc, const char **argv, const char *prefix)
 		 * stray directories.
 		 */
 		if (file_exists(state.dir) && !state.rebasing) {
-			if (resume == RESUME_ABORT) {
+			if (resume == RESUME_ABORT || resume == RESUME_QUIT) {
 				am_destroy(&state);
 				am_state_release(&state);
 				return 0;
@@ -2421,11 +2404,18 @@ int cmd_am(int argc, const char **argv, const char *prefix)
 	case RESUME_ABORT:
 		am_abort(&state);
 		break;
+	case RESUME_QUIT:
+		am_rerere_clear();
+		am_destroy(&state);
+		break;
+	case RESUME_SHOW_PATCH:
+		ret = show_patch(&state);
+		break;
 	default:
-		die("BUG: invalid resume value");
+		BUG("invalid resume value");
 	}
 
 	am_state_release(&state);
 
-	return 0;
+	return ret;
 }