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update-ref.c: extract a new function, parse_next_sha1()
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Replace three functions, update_store_new_sha1(),
update_store_old_sha1(), and parse_next_arg(), with a single function,
parse_next_sha1().  The new function takes care of a whole argument,
including checking whether it is there, converting it to an SHA-1, and
emitting errors on EOF or for invalid values.  The return value
indicates whether the argument was present or absent, which requires
a bit of intelligence because absent values are represented
differently depending on whether "-z" was used.

The new interface means that the calling functions, parse_cmd_*(),
don't have to interpret the result differently based on the
line_termination mode that is in effect.  It also means that
parse_cmd_create() can distinguish unambiguously between an empty new
value and a zeros new value, which fixes a failure in t1400.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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Michael Haggerty authored and Junio C Hamano committed Apr 7, 2014
1 parent 191f241 commit 3afcc46
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Showing 2 changed files with 99 additions and 63 deletions.
160 changes: 98 additions & 62 deletions builtin/update-ref.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -35,27 +35,6 @@ static struct ref_update *update_alloc(void)
return update;
}

static void update_store_new_sha1(const char *command,
struct ref_update *update,
const char *newvalue)
{
if (*newvalue && get_sha1(newvalue, update->new_sha1))
die("%s %s: invalid <newvalue>: %s",
command, update->ref_name, newvalue);
}

static void update_store_old_sha1(const char *command,
struct ref_update *update,
const char *oldvalue)
{
if (*oldvalue && get_sha1(oldvalue, update->old_sha1))
die("%s %s: invalid <oldvalue>: %s",
command, update->ref_name, oldvalue);

/* We have an old value if non-empty, or if empty without -z */
update->have_old = *oldvalue || line_termination;
}

/*
* Parse one whitespace- or NUL-terminated, possibly C-quoted argument
* and append the result to arg. Return a pointer to the terminator.
Expand Down Expand Up @@ -112,35 +91,94 @@ static char *parse_refname(struct strbuf *input, const char **next)
}

/*
* Parse a SP/NUL separator followed by the next SP- or NUL-terminated
* argument, if any. If there is an argument, write it to arg, set
* *next to point at the character terminating the argument, and
* 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 a non-zero result and leave *next unchanged.
* 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_arg(struct strbuf *input, const char **next,
struct strbuf *arg)
static int parse_next_sha1(struct strbuf *input, const char **next,
unsigned char *sha1,
const char *command, const char *refname,
int flags)
{
strbuf_reset(arg);
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;
return 1;
if (**next != ' ')
die("expected SP but got: %s", *next);
die("%s %s: expected SP but got: %s",
command, refname, *next);
(*next)++;
*next = parse_arg(*next, arg);
*next = parse_arg(*next, &arg);
if (arg.len) {
if (get_sha1(arg.buf, sha1))
goto invalid;
} else {
/* Without -z, an empty value means all zeros: */
hashclr(sha1);
}
} else {
/* With -z, read the next NUL-terminated line */
if (**next)
die("expected NUL but got: %s", *next);
die("%s %s: expected NUL but got: %s",
command, refname, *next);
(*next)++;
if (*next == input->buf + input->len)
return -1;
strbuf_addstr(arg, *next);
*next += arg->len;
goto eof;
strbuf_addstr(&arg, *next);
*next += arg.len;

if (arg.len) {
if (get_sha1(arg.buf, sha1))
goto invalid;
} else if (flags & PARSE_SHA1_ALLOW_EMPTY) {
/* With -z, treat an empty value as all zeros: */
hashclr(sha1);
} else {
/*
* With -z, an empty non-required value means
* unspecified:
*/
ret = 1;
}
}
return 0;

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 missing <oldvalue>" :
"%s %s missing <newvalue>",
command, refname);
}


Expand All @@ -156,8 +194,6 @@ static int parse_next_arg(struct strbuf *input, const char **next,

static const char *parse_cmd_update(struct strbuf *input, const char *next)
{
struct strbuf newvalue = STRBUF_INIT;
struct strbuf oldvalue = STRBUF_INIT;
struct ref_update *update;

update = update_alloc();
Expand All @@ -166,24 +202,23 @@ static const char *parse_cmd_update(struct strbuf *input, const char *next)
if (!update->ref_name)
die("update line missing <ref>");

if (!parse_next_arg(input, &next, &newvalue))
update_store_new_sha1("update", update, newvalue.buf);
else
if (parse_next_sha1(input, &next, update->new_sha1,
"update", update->ref_name,
PARSE_SHA1_ALLOW_EMPTY))
die("update %s missing <newvalue>", update->ref_name);

if (!parse_next_arg(input, &next, &oldvalue)) {
update_store_old_sha1("update", update, oldvalue.buf);
if (*next != line_termination)
die("update %s has extra input: %s", update->ref_name, next);
} else if (!line_termination)
die("update %s missing <oldvalue>", update->ref_name);
update->have_old = !parse_next_sha1(input, &next, update->old_sha1,
"update", update->ref_name,
PARSE_SHA1_OLD);

if (*next != line_termination)
die("update %s has extra input: %s", update->ref_name, next);

return next;
}

static const char *parse_cmd_create(struct strbuf *input, const char *next)
{
struct strbuf newvalue = STRBUF_INIT;
struct ref_update *update;

update = update_alloc();
Expand All @@ -192,9 +227,8 @@ static const char *parse_cmd_create(struct strbuf *input, const char *next)
if (!update->ref_name)
die("create line missing <ref>");

if (!parse_next_arg(input, &next, &newvalue))
update_store_new_sha1("create", update, newvalue.buf);
else
if (parse_next_sha1(input, &next, update->new_sha1,
"create", update->ref_name, 0))
die("create %s missing <newvalue>", update->ref_name);

if (is_null_sha1(update->new_sha1))
Expand All @@ -208,7 +242,6 @@ static const char *parse_cmd_create(struct strbuf *input, const char *next)

static const char *parse_cmd_delete(struct strbuf *input, const char *next)
{
struct strbuf oldvalue = STRBUF_INIT;
struct ref_update *update;

update = update_alloc();
Expand All @@ -217,12 +250,14 @@ static const char *parse_cmd_delete(struct strbuf *input, const char *next)
if (!update->ref_name)
die("delete line missing <ref>");

if (!parse_next_arg(input, &next, &oldvalue)) {
update_store_old_sha1("delete", update, oldvalue.buf);
if (update->have_old && is_null_sha1(update->old_sha1))
if (parse_next_sha1(input, &next, update->old_sha1,
"delete", update->ref_name, PARSE_SHA1_OLD)) {
update->have_old = 0;
} else {
if (is_null_sha1(update->old_sha1))
die("delete %s given zero <oldvalue>", update->ref_name);
} else if (!line_termination)
die("delete %s missing <oldvalue>", update->ref_name);
update->have_old = 1;
}

if (*next != line_termination)
die("delete %s has extra input: %s", update->ref_name, next);
Expand All @@ -232,7 +267,6 @@ static const char *parse_cmd_delete(struct strbuf *input, const char *next)

static const char *parse_cmd_verify(struct strbuf *input, const char *next)
{
struct strbuf value = STRBUF_INIT;
struct ref_update *update;

update = update_alloc();
Expand All @@ -241,11 +275,13 @@ static const char *parse_cmd_verify(struct strbuf *input, const char *next)
if (!update->ref_name)
die("verify line missing <ref>");

if (!parse_next_arg(input, &next, &value)) {
update_store_old_sha1("verify", update, value.buf);
if (parse_next_sha1(input, &next, update->old_sha1,
"verify", update->ref_name, PARSE_SHA1_OLD)) {
update->have_old = 0;
} else {
hashcpy(update->new_sha1, update->old_sha1);
} else if (!line_termination)
die("verify %s missing <oldvalue>", update->ref_name);
update->have_old = 1;
}

if (*next != line_termination)
die("verify %s has extra input: %s", update->ref_name, next);
Expand Down
2 changes: 1 addition & 1 deletion t/t1400-update-ref.sh
View file
Original file line number Diff line number Diff line change
Expand Up @@ -858,7 +858,7 @@ test_expect_success 'stdin -z create ref fails with bad new value' '
test_must_fail git rev-parse --verify -q $c
'

test_expect_failure 'stdin -z create ref fails with empty new value' '
test_expect_success 'stdin -z create ref fails with empty new value' '
printf $F "create $c" "" >stdin &&
test_must_fail git update-ref -z --stdin <stdin 2>err &&
grep "fatal: create $c missing <newvalue>" err &&
Expand Down

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