git/builtin/update-ref.c
SZEDER Gábor aee9be2ebe update-ref --stdin: use skip_prefix()
Use skip_prefix() instead of starts_with() and strcmp() when parsing
'git update-ref's stdin to avoid a couple of magic numbers.

Signed-off-by: SZEDER Gábor <szeder.dev@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-06-04 12:26:01 +09:00

445 lines
12 KiB
C

#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 int update_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 = 0;
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 = 0;
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 = 0;
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 = 0;
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;
unsigned int flags = 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 (read_stdin) {
struct strbuf err = STRBUF_INIT;
struct ref_transaction *transaction;
transaction = ref_transaction_begin(&err);
if (!transaction)
die("%s", err.buf);
if (delete || no_deref || 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 (no_deref)
flags = REF_NO_DEREF;
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,
flags);
else
return update_ref(msg, refname, &oid, oldval ? &oldoid : NULL,
flags | create_reflog_flag,
UPDATE_REFS_DIE_ON_ERR);
}