1 files changed, 447 insertions, 0 deletions
diff --git a/builtin/update-ref.c b/builtin/update-ref.c
new file mode 100644
index 0000000..2d8f7f0
--- /dev/null
+++ b/builtin/update-ref.c
@@ -0,0 +1,447 @@
+#include "cache.h"
+#include "config.h"
+#include "refs.h"
+#include "builtin.h"
+#include "parse-options.h"
+#include "quote.h"
+#include "argv-array.h"
+
+static const char * const git_update_ref_usage[] = {
+	N_("git update-ref [<options>] -d <refname> [<old-val>]"),
+	N_("git update-ref [<options>]    <refname> <new-val> [<old-val>]"),
+	N_("git update-ref [<options>] --stdin [-z]"),
+	NULL
+};
+
+static char line_termination = '\n';
+static unsigned int update_flags;
+static unsigned int default_flags;
+static unsigned create_reflog_flag;
+static const char *msg;
+
+/*
+ * Parse one whitespace- or NUL-terminated, possibly C-quoted argument
+ * and append the result to arg.  Return a pointer to the terminator.
+ * Die if there is an error in how the argument is C-quoted.  This
+ * function is only used if not -z.
+ */
+static const char *parse_arg(const char *next, struct strbuf *arg)
+{
+	if (*next == '"') {
+		const char *orig = next;
+
+		if (unquote_c_style(arg, next, &next))
+			die("badly quoted argument: %s", orig);
+		if (*next && !isspace(*next))
+			die("unexpected character after quoted argument: %s", orig);
+	} else {
+		while (*next && !isspace(*next))
+			strbuf_addch(arg, *next++);
+	}
+
+	return next;
+}
+
+/*
+ * Parse the reference name immediately after "command SP".  If not
+ * -z, then handle C-quoting.  Return a pointer to a newly allocated
+ * string containing the name of the reference, or NULL if there was
+ * an error.  Update *next to point at the character that terminates
+ * the argument.  Die if C-quoting is malformed or the reference name
+ * is invalid.
+ */
+static char *parse_refname(struct strbuf *input, const char **next)
+{
+	struct strbuf ref = STRBUF_INIT;
+
+	if (line_termination) {
+		/* Without -z, use the next argument */
+		*next = parse_arg(*next, &ref);
+	} else {
+		/* With -z, use everything up to the next NUL */
+		strbuf_addstr(&ref, *next);
+		*next += ref.len;
+	}
+
+	if (!ref.len) {
+		strbuf_release(&ref);
+		return NULL;
+	}
+
+	if (check_refname_format(ref.buf, REFNAME_ALLOW_ONELEVEL))
+		die("invalid ref format: %s", ref.buf);
+
+	return strbuf_detach(&ref, NULL);
+}
+
+/*
+ * The value being parsed is <oldvalue> (as opposed to <newvalue>; the
+ * difference affects which error messages are generated):
+ */
+#define PARSE_SHA1_OLD 0x01
+
+/*
+ * For backwards compatibility, accept an empty string for update's
+ * <newvalue> in binary mode to be equivalent to specifying zeros.
+ */
+#define PARSE_SHA1_ALLOW_EMPTY 0x02
+
+/*
+ * Parse an argument separator followed by the next argument, if any.
+ * If there is an argument, convert it to a SHA-1, write it to sha1,
+ * set *next to point at the character terminating the argument, and
+ * return 0.  If there is no argument at all (not even the empty
+ * string), return 1 and leave *next unchanged.  If the value is
+ * provided but cannot be converted to a SHA-1, die.  flags can
+ * include PARSE_SHA1_OLD and/or PARSE_SHA1_ALLOW_EMPTY.
+ */
+static int parse_next_oid(struct strbuf *input, const char **next,
+			  struct object_id *oid,
+			  const char *command, const char *refname,
+			  int flags)
+{
+	struct strbuf arg = STRBUF_INIT;
+	int ret = 0;
+
+	if (*next == input->buf + input->len)
+		goto eof;
+
+	if (line_termination) {
+		/* Without -z, consume SP and use next argument */
+		if (!**next || **next == line_termination)
+			return 1;
+		if (**next != ' ')
+			die("%s %s: expected SP but got: %s",
+			    command, refname, *next);
+		(*next)++;
+		*next = parse_arg(*next, &arg);
+		if (arg.len) {
+			if (get_oid(arg.buf, oid))
+				goto invalid;
+		} else {
+			/* Without -z, an empty value means all zeros: */
+			oidclr(oid);
+		}
+	} else {
+		/* With -z, read the next NUL-terminated line */
+		if (**next)
+			die("%s %s: expected NUL but got: %s",
+			    command, refname, *next);
+		(*next)++;
+		if (*next == input->buf + input->len)
+			goto eof;
+		strbuf_addstr(&arg, *next);
+		*next += arg.len;
+
+		if (arg.len) {
+			if (get_oid(arg.buf, oid))
+				goto invalid;
+		} else if (flags & PARSE_SHA1_ALLOW_EMPTY) {
+			/* With -z, treat an empty value as all zeros: */
+			warning("%s %s: missing <newvalue>, treating as zero",
+				command, refname);
+			oidclr(oid);
+		} else {
+			/*
+			 * With -z, an empty non-required value means
+			 * unspecified:
+			 */
+			ret = 1;
+		}
+	}
+
+	strbuf_release(&arg);
+
+	return ret;
+
+ invalid:
+	die(flags & PARSE_SHA1_OLD ?
+	    "%s %s: invalid <oldvalue>: %s" :
+	    "%s %s: invalid <newvalue>: %s",
+	    command, refname, arg.buf);
+
+ eof:
+	die(flags & PARSE_SHA1_OLD ?
+	    "%s %s: unexpected end of input when reading <oldvalue>" :
+	    "%s %s: unexpected end of input when reading <newvalue>",
+	    command, refname);
+}
+
+
+/*
+ * The following five parse_cmd_*() functions parse the corresponding
+ * command.  In each case, next points at the character following the
+ * command name and the following space.  They each return a pointer
+ * to the character terminating the command, and die with an
+ * explanatory message if there are any parsing problems.  All of
+ * these functions handle either text or binary format input,
+ * depending on how line_termination is set.
+ */
+
+static const char *parse_cmd_update(struct ref_transaction *transaction,
+				    struct strbuf *input, const char *next)
+{
+	struct strbuf err = STRBUF_INIT;
+	char *refname;
+	struct object_id new_oid, old_oid;
+	int have_old;
+
+	refname = parse_refname(input, &next);
+	if (!refname)
+		die("update: missing <ref>");
+
+	if (parse_next_oid(input, &next, &new_oid, "update", refname,
+			   PARSE_SHA1_ALLOW_EMPTY))
+		die("update %s: missing <newvalue>", refname);
+
+	have_old = !parse_next_oid(input, &next, &old_oid, "update", refname,
+				   PARSE_SHA1_OLD);
+
+	if (*next != line_termination)
+		die("update %s: extra input: %s", refname, next);
+
+	if (ref_transaction_update(transaction, refname,
+				   &new_oid, have_old ? &old_oid : NULL,
+				   update_flags | create_reflog_flag,
+				   msg, &err))
+		die("%s", err.buf);
+
+	update_flags = default_flags;
+	free(refname);
+	strbuf_release(&err);
+
+	return next;
+}
+
+static const char *parse_cmd_create(struct ref_transaction *transaction,
+				    struct strbuf *input, const char *next)
+{
+	struct strbuf err = STRBUF_INIT;
+	char *refname;
+	struct object_id new_oid;
+
+	refname = parse_refname(input, &next);
+	if (!refname)
+		die("create: missing <ref>");
+
+	if (parse_next_oid(input, &next, &new_oid, "create", refname, 0))
+		die("create %s: missing <newvalue>", refname);
+
+	if (is_null_oid(&new_oid))
+		die("create %s: zero <newvalue>", refname);
+
+	if (*next != line_termination)
+		die("create %s: extra input: %s", refname, next);
+
+	if (ref_transaction_create(transaction, refname, &new_oid,
+				   update_flags | create_reflog_flag,
+				   msg, &err))
+		die("%s", err.buf);
+
+	update_flags = default_flags;
+	free(refname);
+	strbuf_release(&err);
+
+	return next;
+}
+
+static const char *parse_cmd_delete(struct ref_transaction *transaction,
+				    struct strbuf *input, const char *next)
+{
+	struct strbuf err = STRBUF_INIT;
+	char *refname;
+	struct object_id old_oid;
+	int have_old;
+
+	refname = parse_refname(input, &next);
+	if (!refname)
+		die("delete: missing <ref>");
+
+	if (parse_next_oid(input, &next, &old_oid, "delete", refname,
+			   PARSE_SHA1_OLD)) {
+		have_old = 0;
+	} else {
+		if (is_null_oid(&old_oid))
+			die("delete %s: zero <oldvalue>", refname);
+		have_old = 1;
+	}
+
+	if (*next != line_termination)
+		die("delete %s: extra input: %s", refname, next);
+
+	if (ref_transaction_delete(transaction, refname,
+				   have_old ? &old_oid : NULL,
+				   update_flags, msg, &err))
+		die("%s", err.buf);
+
+	update_flags = default_flags;
+	free(refname);
+	strbuf_release(&err);
+
+	return next;
+}
+
+static const char *parse_cmd_verify(struct ref_transaction *transaction,
+				    struct strbuf *input, const char *next)
+{
+	struct strbuf err = STRBUF_INIT;
+	char *refname;
+	struct object_id old_oid;
+
+	refname = parse_refname(input, &next);
+	if (!refname)
+		die("verify: missing <ref>");
+
+	if (parse_next_oid(input, &next, &old_oid, "verify", refname,
+			   PARSE_SHA1_OLD))
+		oidclr(&old_oid);
+
+	if (*next != line_termination)
+		die("verify %s: extra input: %s", refname, next);
+
+	if (ref_transaction_verify(transaction, refname, &old_oid,
+				   update_flags, &err))
+		die("%s", err.buf);
+
+	update_flags = default_flags;
+	free(refname);
+	strbuf_release(&err);
+
+	return next;
+}
+
+static const char *parse_cmd_option(struct strbuf *input, const char *next)
+{
+	const char *rest;
+	if (skip_prefix(next, "no-deref", &rest) && *rest == line_termination)
+		update_flags |= REF_NO_DEREF;
+	else
+		die("option unknown: %s", next);
+	return rest;
+}
+
+static void update_refs_stdin(struct ref_transaction *transaction)
+{
+	struct strbuf input = STRBUF_INIT;
+	const char *next;
+
+	if (strbuf_read(&input, 0, 1000) < 0)
+		die_errno("could not read from stdin");
+	next = input.buf;
+	/* Read each line dispatch its command */
+	while (next < input.buf + input.len) {
+		if (*next == line_termination)
+			die("empty command in input");
+		else if (isspace(*next))
+			die("whitespace before command: %s", next);
+		else if (skip_prefix(next, "update ", &next))
+			next = parse_cmd_update(transaction, &input, next);
+		else if (skip_prefix(next, "create ", &next))
+			next = parse_cmd_create(transaction, &input, next);
+		else if (skip_prefix(next, "delete ", &next))
+			next = parse_cmd_delete(transaction, &input, next);
+		else if (skip_prefix(next, "verify ", &next))
+			next = parse_cmd_verify(transaction, &input, next);
+		else if (skip_prefix(next, "option ", &next))
+			next = parse_cmd_option(&input, next);
+		else
+			die("unknown command: %s", next);
+
+		next++;
+	}
+
+	strbuf_release(&input);
+}
+
+int cmd_update_ref(int argc, const char **argv, const char *prefix)
+{
+	const char *refname, *oldval;
+	struct object_id oid, oldoid;
+	int delete = 0, no_deref = 0, read_stdin = 0, end_null = 0;
+	int create_reflog = 0;
+	struct option options[] = {
+		OPT_STRING( 'm', NULL, &msg, N_("reason"), N_("reason of the update")),
+		OPT_BOOL('d', NULL, &delete, N_("delete the reference")),
+		OPT_BOOL( 0 , "no-deref", &no_deref,
+					N_("update <refname> not the one it points to")),
+		OPT_BOOL('z', NULL, &end_null, N_("stdin has NUL-terminated arguments")),
+		OPT_BOOL( 0 , "stdin", &read_stdin, N_("read updates from stdin")),
+		OPT_BOOL( 0 , "create-reflog", &create_reflog, N_("create a reflog")),
+		OPT_END(),
+	};
+
+	git_config(git_default_config, NULL);
+	argc = parse_options(argc, argv, prefix, options, git_update_ref_usage,
+			     0);
+	if (msg && !*msg)
+		die("Refusing to perform update with empty message.");
+
+	create_reflog_flag = create_reflog ? REF_FORCE_CREATE_REFLOG : 0;
+
+	if (no_deref) {
+		default_flags = REF_NO_DEREF;
+		update_flags = default_flags;
+	}
+
+	if (read_stdin) {
+		struct strbuf err = STRBUF_INIT;
+		struct ref_transaction *transaction;
+
+		transaction = ref_transaction_begin(&err);
+		if (!transaction)
+			die("%s", err.buf);
+		if (delete || argc > 0)
+			usage_with_options(git_update_ref_usage, options);
+		if (end_null)
+			line_termination = '\0';
+		update_refs_stdin(transaction);
+		if (ref_transaction_commit(transaction, &err))
+			die("%s", err.buf);
+		ref_transaction_free(transaction);
+		strbuf_release(&err);
+		return 0;
+	}
+
+	if (end_null)
+		usage_with_options(git_update_ref_usage, options);
+
+	if (delete) {
+		if (argc < 1 || argc > 2)
+			usage_with_options(git_update_ref_usage, options);
+		refname = argv[0];
+		oldval = argv[1];
+	} else {
+		const char *value;
+		if (argc < 2 || argc > 3)
+			usage_with_options(git_update_ref_usage, options);
+		refname = argv[0];
+		value = argv[1];
+		oldval = argv[2];
+		if (get_oid(value, &oid))
+			die("%s: not a valid SHA1", value);
+	}
+
+	if (oldval) {
+		if (!*oldval)
+			/*
+			 * The empty string implies that the reference
+			 * must not already exist:
+			 */
+			oidclr(&oldoid);
+		else if (get_oid(oldval, &oldoid))
+			die("%s: not a valid old SHA1", oldval);
+	}
+
+	if (delete)
+		/*
+		 * For purposes of backwards compatibility, we treat
+		 * NULL_SHA1 as "don't care" here:
+		 */
+		return delete_ref(msg, refname,
+				  (oldval && !is_null_oid(&oldoid)) ? &oldoid : NULL,
+				  default_flags);
+	else
+		return update_ref(msg, refname, &oid, oldval ? &oldoid : NULL,
+				  default_flags | create_reflog_flag,
+				  UPDATE_REFS_DIE_ON_ERR);
+}