[PATCHv3] pathspec: allow escaped query values
- From
Stefan Beller <sbeller@google.com>
- Date
- Jun 2, 2016, 23:14 UTC
- Message-ID
- <20160602231413.9028-1-sbeller@google.com>
In our own .gitattributes file we have attributes such as:
*.[ch] whitespace=indent,trail,space
When querying for attributes we want to be able to ask for the exact value, i.e.
git ls-files :(attr:whitespace=indent,trail,space)
should work, but the commas are used in the attr magic to introduce the next attr, such that this query currently fails with
fatal: Invalid pathspec magic 'trail' in ':(attr:whitespace=indent,trail,space)'
This change allows escaping characters by a backslash, such that the query
git ls-files :(attr:whitespace=indent\,trail\,space)
will match all path that have the value "indent,trail,space" for the whitespace attribute. To accomplish this, we need to modify two places. First `eat_long_magic` needs to not stop early upon seeing a comma or closing paren that is escaped. As a second step we need to remove any escaping from the attr value.
Helped-by: Junio C Hamano <gitster@pobox.com> Signed-off-by: Stefan Beller <sbeller@google.com> ---
> That would be true _only_ when "find next escape and copy up to that > byte" aka "scanning once with optimized strchr(), and copying once > with optimized memmove()" is faster than "scanning once and copying" > loop.
Oh right. that would work for larger strings that don't fit into a cache very well, but in our expected case this will do.
> I was merely reacting to your use of memmove() in a very different > loop, where if you unescape "a\b\c\defghijk", your memmove() would > move "efghijk" many times.
Right, at the time of writing I didn't like it, but was ok with it as we only have a few escapes.
> Also the handling of the terminating NUL may need to be > updated.
I don't think so.
> That is why I did not say "replace yours with this", but > merely "along the lines of this" ;-)
This is pretty much your code modulo nits (xmalloz, semicolons) now, and I am convinced it works by the test.
However if we add a value restriction here, we need to be as strict in the .gitattributes parsing as well and put a warning there (similar to invalid_attr_name_message) I would think.
Thanks, Stefan
pathspec.c | 52 +++++++++++++++++++++++++++++++++++++---- t/t6134-pathspec-with-labels.sh | 10 ++++++++ 2 files changed, 58 insertions(+), 4 deletions(-)
diff --git a/pathspec.c b/pathspec.c index 326863a..fe53ddf 100644 --- a/pathspec.c +++ b/pathspec.c @@ -89,6 +89,51 @@ static void prefix_short_magic(struct strbuf *sb, int prefixlen, strbuf_addf(sb, ",prefix:%d)", prefixlen); } +static size_t strcspn_escaped(const char *s, const char *stop) +{ + const char *i; + + for (i = s; *i; i++) { + /* skip the escaped character */ + if (i[0] == '\\' && i[1]) { + i++; + continue; + } + + if (strchr(stop, *i)) + break; + } + return i - s; +} + +static inline int invalid_value_char(const char ch) +{ + if (isalnum(ch) || strchr(",-_", ch)) + return 0; + return -1; +} + +static char *attr_value_unescape(const char *value) +{ + const char *src; + char *dst, *ret; + + ret = xmallocz(strlen(value)); + for (src = value, dst = ret; *src; src++, dst++) { + if (*src == '\\') { + if (!src[1]) + die(_("Escape character '\\' not allowed as " + "last character in attr value")); + src++; + } + if (*src && invalid_value_char(*src)) + die("cannot use '%c' for value matching", *src); + *dst = *src; + } + *dst = '\0'; + return ret; +} + static void parse_pathspec_attr_match(struct pathspec_item *item, const char *value) { struct string_list_item *si; @@ -131,10 +176,9 @@ static void parse_pathspec_attr_match(struct pathspec_item *item, const char *va if (attr[attr_len] != '=') am->match_mode = MATCH_SET; else { + const char *v = &attr[attr_len + 1]; am->match_mode = MATCH_VALUE; - am->value = xstrdup(&attr[attr_len + 1]); - if (strchr(am->value, '\\')) - die(_("attr spec values must not contain backslashes")); + am->value = attr_value_unescape(v); } break; } @@ -166,7 +210,7 @@ static void eat_long_magic(struct pathspec_item *item, const char *elt, for (copyfrom = elt + 2; *copyfrom && *copyfrom != ')'; copyfrom = nextat) { - size_t len = strcspn(copyfrom, ",)"); + size_t len = strcspn_escaped(copyfrom, ",)"); if (copyfrom[len] == ',') nextat = copyfrom + len + 1; else diff --git a/t/t6134-pathspec-with-labels.sh b/t/t6134-pathspec-with-labels.sh index a5c9632..f1e355f 100755 --- a/t/t6134-pathspec-with-labels.sh +++ b/t/t6134-pathspec-with-labels.sh @@ -163,4 +163,14 @@ test_expect_success 'abort on asking for wrong magic' ' test_must_fail git ls-files . ":(attr:!label=foo)" ' +test_expect_success 'check attribute list' ' + cat <<-EOF >>.gitattributes && + * whitespace=indent,trail,space + EOF + cat .gitattributes && + git ls-files ":(attr:whitespace=indent\,trail\,space)" >actual && + git ls-files >expect && + test_cmp expect actual +' + test_done
-- 2.8.2.126.g9068a9d.dirty