git-commit-vandalism/attr.c
Jeff King 1afca44495 attr: don't confuse prefixes with leading directories
When we prepare the attribute stack for a lookup on a path,
we start with the cached stack from the previous lookup
(because it is common to do several lookups in the same
directory hierarchy). So the first thing we must do in
preparing the stack is to pop any entries that point to
directories we are no longer interested in.

For example, if our stack contains gitattributes for:

  foo/bar/baz
  foo/bar
  foo

but we want to do a lookup in "foo/bar/bleep", then we want
to pop the top element, but retain the others.

To do this we walk down the stack from the top, popping
elements that do not match our lookup directory. However,
the test do this simply checked strncmp, meaning we would
mistake "foo/bar/baz" as a leading directory of
"foo/bar/baz_plus". We must also check that the character
after our match is '/', meaning we matched the whole path
component.

There are two special cases to consider:

  1. The top of our attr stack has the empty path. So we
     must not check for '/', but rather special-case the
     empty path, which always matches.

  2. Typically when matching paths in this way, you would
     also need to check for a full string match (i.e., the
     character after is '\0'). We don't need to do so in
     this case, though, because our path string is actually
     just the directory component of the path to a file
     (i.e., we know that it terminates with "/", because the
     filename comes after that).

Helped-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2012-01-10 11:25:40 -08:00

750 lines
17 KiB
C

#define NO_THE_INDEX_COMPATIBILITY_MACROS
#include "cache.h"
#include "exec_cmd.h"
#include "attr.h"
const char git_attr__true[] = "(builtin)true";
const char git_attr__false[] = "\0(builtin)false";
static const char git_attr__unknown[] = "(builtin)unknown";
#define ATTR__TRUE git_attr__true
#define ATTR__FALSE git_attr__false
#define ATTR__UNSET NULL
#define ATTR__UNKNOWN git_attr__unknown
static const char *attributes_file;
/*
* The basic design decision here is that we are not going to have
* insanely large number of attributes.
*
* This is a randomly chosen prime.
*/
#define HASHSIZE 257
#ifndef DEBUG_ATTR
#define DEBUG_ATTR 0
#endif
struct git_attr {
struct git_attr *next;
unsigned h;
int attr_nr;
char name[FLEX_ARRAY];
};
static int attr_nr;
static struct git_attr_check *check_all_attr;
static struct git_attr *(git_attr_hash[HASHSIZE]);
static unsigned hash_name(const char *name, int namelen)
{
unsigned val = 0, c;
while (namelen--) {
c = *name++;
val = ((val << 7) | (val >> 22)) ^ c;
}
return val;
}
static int invalid_attr_name(const char *name, int namelen)
{
/*
* Attribute name cannot begin with '-' and from
* [-A-Za-z0-9_.]. We'd specifically exclude '=' for now,
* as we might later want to allow non-binary value for
* attributes, e.g. "*.svg merge=special-merge-program-for-svg"
*/
if (*name == '-')
return -1;
while (namelen--) {
char ch = *name++;
if (! (ch == '-' || ch == '.' || ch == '_' ||
('0' <= ch && ch <= '9') ||
('a' <= ch && ch <= 'z') ||
('A' <= ch && ch <= 'Z')) )
return -1;
}
return 0;
}
static struct git_attr *git_attr_internal(const char *name, int len)
{
unsigned hval = hash_name(name, len);
unsigned pos = hval % HASHSIZE;
struct git_attr *a;
for (a = git_attr_hash[pos]; a; a = a->next) {
if (a->h == hval &&
!memcmp(a->name, name, len) && !a->name[len])
return a;
}
if (invalid_attr_name(name, len))
return NULL;
a = xmalloc(sizeof(*a) + len + 1);
memcpy(a->name, name, len);
a->name[len] = 0;
a->h = hval;
a->next = git_attr_hash[pos];
a->attr_nr = attr_nr++;
git_attr_hash[pos] = a;
check_all_attr = xrealloc(check_all_attr,
sizeof(*check_all_attr) * attr_nr);
check_all_attr[a->attr_nr].attr = a;
check_all_attr[a->attr_nr].value = ATTR__UNKNOWN;
return a;
}
struct git_attr *git_attr(const char *name)
{
return git_attr_internal(name, strlen(name));
}
/*
* .gitattributes file is one line per record, each of which is
*
* (1) glob pattern.
* (2) whitespace
* (3) whitespace separated list of attribute names, each of which
* could be prefixed with '-' to mean "set to false", '!' to mean
* "unset".
*/
/* What does a matched pattern decide? */
struct attr_state {
struct git_attr *attr;
const char *setto;
};
struct match_attr {
union {
char *pattern;
struct git_attr *attr;
} u;
char is_macro;
unsigned num_attr;
struct attr_state state[FLEX_ARRAY];
};
static const char blank[] = " \t\r\n";
static const char *parse_attr(const char *src, int lineno, const char *cp,
int *num_attr, struct match_attr *res)
{
const char *ep, *equals;
int len;
ep = cp + strcspn(cp, blank);
equals = strchr(cp, '=');
if (equals && ep < equals)
equals = NULL;
if (equals)
len = equals - cp;
else
len = ep - cp;
if (!res) {
if (*cp == '-' || *cp == '!') {
cp++;
len--;
}
if (invalid_attr_name(cp, len)) {
fprintf(stderr,
"%.*s is not a valid attribute name: %s:%d\n",
len, cp, src, lineno);
return NULL;
}
} else {
struct attr_state *e;
e = &(res->state[*num_attr]);
if (*cp == '-' || *cp == '!') {
e->setto = (*cp == '-') ? ATTR__FALSE : ATTR__UNSET;
cp++;
len--;
}
else if (!equals)
e->setto = ATTR__TRUE;
else {
e->setto = xmemdupz(equals + 1, ep - equals - 1);
}
e->attr = git_attr_internal(cp, len);
}
(*num_attr)++;
return ep + strspn(ep, blank);
}
static struct match_attr *parse_attr_line(const char *line, const char *src,
int lineno, int macro_ok)
{
int namelen;
int num_attr;
const char *cp, *name;
struct match_attr *res = NULL;
int pass;
int is_macro;
cp = line + strspn(line, blank);
if (!*cp || *cp == '#')
return NULL;
name = cp;
namelen = strcspn(name, blank);
if (strlen(ATTRIBUTE_MACRO_PREFIX) < namelen &&
!prefixcmp(name, ATTRIBUTE_MACRO_PREFIX)) {
if (!macro_ok) {
fprintf(stderr, "%s not allowed: %s:%d\n",
name, src, lineno);
return NULL;
}
is_macro = 1;
name += strlen(ATTRIBUTE_MACRO_PREFIX);
name += strspn(name, blank);
namelen = strcspn(name, blank);
if (invalid_attr_name(name, namelen)) {
fprintf(stderr,
"%.*s is not a valid attribute name: %s:%d\n",
namelen, name, src, lineno);
return NULL;
}
}
else
is_macro = 0;
for (pass = 0; pass < 2; pass++) {
/* pass 0 counts and allocates, pass 1 fills */
num_attr = 0;
cp = name + namelen;
cp = cp + strspn(cp, blank);
while (*cp) {
cp = parse_attr(src, lineno, cp, &num_attr, res);
if (!cp)
return NULL;
}
if (pass)
break;
res = xcalloc(1,
sizeof(*res) +
sizeof(struct attr_state) * num_attr +
(is_macro ? 0 : namelen + 1));
if (is_macro)
res->u.attr = git_attr_internal(name, namelen);
else {
res->u.pattern = (char *)&(res->state[num_attr]);
memcpy(res->u.pattern, name, namelen);
res->u.pattern[namelen] = 0;
}
res->is_macro = is_macro;
res->num_attr = num_attr;
}
return res;
}
/*
* Like info/exclude and .gitignore, the attribute information can
* come from many places.
*
* (1) .gitattribute file of the same directory;
* (2) .gitattribute file of the parent directory if (1) does not have
* any match; this goes recursively upwards, just like .gitignore.
* (3) $GIT_DIR/info/attributes, which overrides both of the above.
*
* In the same file, later entries override the earlier match, so in the
* global list, we would have entries from info/attributes the earliest
* (reading the file from top to bottom), .gitattribute of the root
* directory (again, reading the file from top to bottom) down to the
* current directory, and then scan the list backwards to find the first match.
* This is exactly the same as what excluded() does in dir.c to deal with
* .gitignore
*/
static struct attr_stack {
struct attr_stack *prev;
char *origin;
unsigned num_matches;
unsigned alloc;
struct match_attr **attrs;
} *attr_stack;
static void free_attr_elem(struct attr_stack *e)
{
int i;
free(e->origin);
for (i = 0; i < e->num_matches; i++) {
struct match_attr *a = e->attrs[i];
int j;
for (j = 0; j < a->num_attr; j++) {
const char *setto = a->state[j].setto;
if (setto == ATTR__TRUE ||
setto == ATTR__FALSE ||
setto == ATTR__UNSET ||
setto == ATTR__UNKNOWN)
;
else
free((char *) setto);
}
free(a);
}
free(e);
}
static const char *builtin_attr[] = {
"[attr]binary -diff -text",
NULL,
};
static void handle_attr_line(struct attr_stack *res,
const char *line,
const char *src,
int lineno,
int macro_ok)
{
struct match_attr *a;
a = parse_attr_line(line, src, lineno, macro_ok);
if (!a)
return;
if (res->alloc <= res->num_matches) {
res->alloc = alloc_nr(res->num_matches);
res->attrs = xrealloc(res->attrs,
sizeof(struct match_attr *) *
res->alloc);
}
res->attrs[res->num_matches++] = a;
}
static struct attr_stack *read_attr_from_array(const char **list)
{
struct attr_stack *res;
const char *line;
int lineno = 0;
res = xcalloc(1, sizeof(*res));
while ((line = *(list++)) != NULL)
handle_attr_line(res, line, "[builtin]", ++lineno, 1);
return res;
}
static enum git_attr_direction direction;
static struct index_state *use_index;
static struct attr_stack *read_attr_from_file(const char *path, int macro_ok)
{
FILE *fp = fopen(path, "r");
struct attr_stack *res;
char buf[2048];
int lineno = 0;
if (!fp)
return NULL;
res = xcalloc(1, sizeof(*res));
while (fgets(buf, sizeof(buf), fp))
handle_attr_line(res, buf, path, ++lineno, macro_ok);
fclose(fp);
return res;
}
static void *read_index_data(const char *path)
{
int pos, len;
unsigned long sz;
enum object_type type;
void *data;
struct index_state *istate = use_index ? use_index : &the_index;
len = strlen(path);
pos = index_name_pos(istate, path, len);
if (pos < 0) {
/*
* We might be in the middle of a merge, in which
* case we would read stage #2 (ours).
*/
int i;
for (i = -pos - 1;
(pos < 0 && i < istate->cache_nr &&
!strcmp(istate->cache[i]->name, path));
i++)
if (ce_stage(istate->cache[i]) == 2)
pos = i;
}
if (pos < 0)
return NULL;
data = read_sha1_file(istate->cache[pos]->sha1, &type, &sz);
if (!data || type != OBJ_BLOB) {
free(data);
return NULL;
}
return data;
}
static struct attr_stack *read_attr_from_index(const char *path, int macro_ok)
{
struct attr_stack *res;
char *buf, *sp;
int lineno = 0;
buf = read_index_data(path);
if (!buf)
return NULL;
res = xcalloc(1, sizeof(*res));
for (sp = buf; *sp; ) {
char *ep;
int more;
for (ep = sp; *ep && *ep != '\n'; ep++)
;
more = (*ep == '\n');
*ep = '\0';
handle_attr_line(res, sp, path, ++lineno, macro_ok);
sp = ep + more;
}
free(buf);
return res;
}
static struct attr_stack *read_attr(const char *path, int macro_ok)
{
struct attr_stack *res;
if (direction == GIT_ATTR_CHECKOUT) {
res = read_attr_from_index(path, macro_ok);
if (!res)
res = read_attr_from_file(path, macro_ok);
}
else if (direction == GIT_ATTR_CHECKIN) {
res = read_attr_from_file(path, macro_ok);
if (!res)
/*
* There is no checked out .gitattributes file there, but
* we might have it in the index. We allow operation in a
* sparsely checked out work tree, so read from it.
*/
res = read_attr_from_index(path, macro_ok);
}
else
res = read_attr_from_index(path, macro_ok);
if (!res)
res = xcalloc(1, sizeof(*res));
return res;
}
#if DEBUG_ATTR
static void debug_info(const char *what, struct attr_stack *elem)
{
fprintf(stderr, "%s: %s\n", what, elem->origin ? elem->origin : "()");
}
static void debug_set(const char *what, const char *match, struct git_attr *attr, const void *v)
{
const char *value = v;
if (ATTR_TRUE(value))
value = "set";
else if (ATTR_FALSE(value))
value = "unset";
else if (ATTR_UNSET(value))
value = "unspecified";
fprintf(stderr, "%s: %s => %s (%s)\n",
what, attr->name, (char *) value, match);
}
#define debug_push(a) debug_info("push", (a))
#define debug_pop(a) debug_info("pop", (a))
#else
#define debug_push(a) do { ; } while (0)
#define debug_pop(a) do { ; } while (0)
#define debug_set(a,b,c,d) do { ; } while (0)
#endif
static void drop_attr_stack(void)
{
while (attr_stack) {
struct attr_stack *elem = attr_stack;
attr_stack = elem->prev;
free_attr_elem(elem);
}
}
static const char *git_etc_gitattributes(void)
{
static const char *system_wide;
if (!system_wide)
system_wide = system_path(ETC_GITATTRIBUTES);
return system_wide;
}
static int git_attr_system(void)
{
return !git_env_bool("GIT_ATTR_NOSYSTEM", 0);
}
static int git_attr_config(const char *var, const char *value, void *dummy)
{
if (!strcmp(var, "core.attributesfile"))
return git_config_pathname(&attributes_file, var, value);
return 0;
}
static void bootstrap_attr_stack(void)
{
if (!attr_stack) {
struct attr_stack *elem;
elem = read_attr_from_array(builtin_attr);
elem->origin = NULL;
elem->prev = attr_stack;
attr_stack = elem;
if (git_attr_system()) {
elem = read_attr_from_file(git_etc_gitattributes(), 1);
if (elem) {
elem->origin = NULL;
elem->prev = attr_stack;
attr_stack = elem;
}
}
git_config(git_attr_config, NULL);
if (attributes_file) {
elem = read_attr_from_file(attributes_file, 1);
if (elem) {
elem->origin = NULL;
elem->prev = attr_stack;
attr_stack = elem;
}
}
if (!is_bare_repository() || direction == GIT_ATTR_INDEX) {
elem = read_attr(GITATTRIBUTES_FILE, 1);
elem->origin = strdup("");
elem->prev = attr_stack;
attr_stack = elem;
debug_push(elem);
}
elem = read_attr_from_file(git_path(INFOATTRIBUTES_FILE), 1);
if (!elem)
elem = xcalloc(1, sizeof(*elem));
elem->origin = NULL;
elem->prev = attr_stack;
attr_stack = elem;
}
}
static void prepare_attr_stack(const char *path, int dirlen)
{
struct attr_stack *elem, *info;
int len;
struct strbuf pathbuf;
strbuf_init(&pathbuf, dirlen+2+strlen(GITATTRIBUTES_FILE));
/*
* At the bottom of the attribute stack is the built-in
* set of attribute definitions, followed by the contents
* of $(prefix)/etc/gitattributes and a file specified by
* core.attributesfile. Then, contents from
* .gitattribute files from directories closer to the
* root to the ones in deeper directories are pushed
* to the stack. Finally, at the very top of the stack
* we always keep the contents of $GIT_DIR/info/attributes.
*
* When checking, we use entries from near the top of the
* stack, preferring $GIT_DIR/info/attributes, then
* .gitattributes in deeper directories to shallower ones,
* and finally use the built-in set as the default.
*/
if (!attr_stack)
bootstrap_attr_stack();
/*
* Pop the "info" one that is always at the top of the stack.
*/
info = attr_stack;
attr_stack = info->prev;
/*
* Pop the ones from directories that are not the prefix of
* the path we are checking.
*/
while (attr_stack && attr_stack->origin) {
int namelen = strlen(attr_stack->origin);
elem = attr_stack;
if (namelen <= dirlen &&
!strncmp(elem->origin, path, namelen) &&
(!namelen || path[namelen] == '/'))
break;
debug_pop(elem);
attr_stack = elem->prev;
free_attr_elem(elem);
}
/*
* Read from parent directories and push them down
*/
if (!is_bare_repository() || direction == GIT_ATTR_INDEX) {
while (1) {
char *cp;
len = strlen(attr_stack->origin);
if (dirlen <= len)
break;
strbuf_reset(&pathbuf);
strbuf_add(&pathbuf, path, dirlen);
strbuf_addch(&pathbuf, '/');
cp = strchr(pathbuf.buf + len + 1, '/');
strcpy(cp + 1, GITATTRIBUTES_FILE);
elem = read_attr(pathbuf.buf, 0);
*cp = '\0';
elem->origin = strdup(pathbuf.buf);
elem->prev = attr_stack;
attr_stack = elem;
debug_push(elem);
}
}
strbuf_release(&pathbuf);
/*
* Finally push the "info" one at the top of the stack.
*/
info->prev = attr_stack;
attr_stack = info;
}
static int path_matches(const char *pathname, int pathlen,
const char *pattern,
const char *base, int baselen)
{
if (!strchr(pattern, '/')) {
/* match basename */
const char *basename = strrchr(pathname, '/');
basename = basename ? basename + 1 : pathname;
return (fnmatch(pattern, basename, 0) == 0);
}
/*
* match with FNM_PATHNAME; the pattern has base implicitly
* in front of it.
*/
if (*pattern == '/')
pattern++;
if (pathlen < baselen ||
(baselen && pathname[baselen] != '/') ||
strncmp(pathname, base, baselen))
return 0;
if (baselen != 0)
baselen++;
return fnmatch(pattern, pathname + baselen, FNM_PATHNAME) == 0;
}
static int macroexpand_one(int attr_nr, int rem);
static int fill_one(const char *what, struct match_attr *a, int rem)
{
struct git_attr_check *check = check_all_attr;
int i;
for (i = a->num_attr - 1; 0 < rem && 0 <= i; i--) {
struct git_attr *attr = a->state[i].attr;
const char **n = &(check[attr->attr_nr].value);
const char *v = a->state[i].setto;
if (*n == ATTR__UNKNOWN) {
debug_set(what,
a->is_macro ? a->u.attr->name : a->u.pattern,
attr, v);
*n = v;
rem--;
rem = macroexpand_one(attr->attr_nr, rem);
}
}
return rem;
}
static int fill(const char *path, int pathlen, struct attr_stack *stk, int rem)
{
int i;
const char *base = stk->origin ? stk->origin : "";
for (i = stk->num_matches - 1; 0 < rem && 0 <= i; i--) {
struct match_attr *a = stk->attrs[i];
if (a->is_macro)
continue;
if (path_matches(path, pathlen,
a->u.pattern, base, strlen(base)))
rem = fill_one("fill", a, rem);
}
return rem;
}
static int macroexpand_one(int attr_nr, int rem)
{
struct attr_stack *stk;
struct match_attr *a = NULL;
int i;
if (check_all_attr[attr_nr].value != ATTR__TRUE)
return rem;
for (stk = attr_stack; !a && stk; stk = stk->prev)
for (i = stk->num_matches - 1; !a && 0 <= i; i--) {
struct match_attr *ma = stk->attrs[i];
if (!ma->is_macro)
continue;
if (ma->u.attr->attr_nr == attr_nr)
a = ma;
}
if (a)
rem = fill_one("expand", a, rem);
return rem;
}
int git_checkattr(const char *path, int num, struct git_attr_check *check)
{
struct attr_stack *stk;
const char *cp;
int dirlen, pathlen, i, rem;
bootstrap_attr_stack();
for (i = 0; i < attr_nr; i++)
check_all_attr[i].value = ATTR__UNKNOWN;
pathlen = strlen(path);
cp = strrchr(path, '/');
if (!cp)
dirlen = 0;
else
dirlen = cp - path;
prepare_attr_stack(path, dirlen);
rem = attr_nr;
for (stk = attr_stack; 0 < rem && stk; stk = stk->prev)
rem = fill(path, pathlen, stk, rem);
for (i = 0; i < num; i++) {
const char *value = check_all_attr[check[i].attr->attr_nr].value;
if (value == ATTR__UNKNOWN)
value = ATTR__UNSET;
check[i].value = value;
}
return 0;
}
void git_attr_set_direction(enum git_attr_direction new, struct index_state *istate)
{
enum git_attr_direction old = direction;
if (is_bare_repository() && new != GIT_ATTR_INDEX)
die("BUG: non-INDEX attr direction in a bare repo");
direction = new;
if (new != old)
drop_attr_stack();
use_index = istate;
}