git/attr.c
Jeff King 96ffc06f72 convert trivial cases to FLEX_ARRAY macros
Using FLEX_ARRAY macros reduces the amount of manual
computation size we have to do. It also ensures we don't
overflow size_t, and it makes sure we write the same number
of bytes that we allocated.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-02-22 14:51:09 -08:00

826 lines
20 KiB
C

/*
* Handle git attributes. See gitattributes(5) for a description of
* the file syntax, and Documentation/technical/api-gitattributes.txt
* for a description of the API.
*
* One basic design decision here is that we are not going to support
* an insanely large number of attributes.
*/
#define NO_THE_INDEX_COMPATIBILITY_MACROS
#include "cache.h"
#include "exec_cmd.h"
#include "attr.h"
#include "dir.h"
#include "utf8.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
/* 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;
int maybe_macro;
int maybe_real;
char name[FLEX_ARRAY];
};
static int attr_nr;
static int cannot_trust_maybe_real;
static struct git_attr_check *check_all_attr;
static struct git_attr *(git_attr_hash[HASHSIZE]);
char *git_attr_name(struct git_attr *attr)
{
return attr->name;
}
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 must consist of
* characters from [-A-Za-z0-9_.].
*/
if (namelen <= 0 || *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;
FLEX_ALLOC_MEM(a, name, name, len);
a->h = hval;
a->next = git_attr_hash[pos];
a->attr_nr = attr_nr++;
a->maybe_macro = 0;
a->maybe_real = 0;
git_attr_hash[pos] = a;
REALLOC_ARRAY(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));
}
/* What does a matched pattern decide? */
struct attr_state {
struct git_attr *attr;
const char *setto;
};
struct pattern {
const char *pattern;
int patternlen;
int nowildcardlen;
int flags; /* EXC_FLAG_* */
};
/*
* One rule, as from a .gitattributes file.
*
* If is_macro is true, then u.attr is a pointer to the git_attr being
* defined.
*
* If is_macro is false, then u.pattern points at the filename pattern
* to which the rule applies. (The memory pointed to is part of the
* memory block allocated for the match_attr instance.)
*
* In either case, num_attr is the number of attributes affected by
* this rule, and state is an array listing them. The attributes are
* listed as they appear in the file (macros unexpanded).
*/
struct match_attr {
union {
struct pattern pat;
struct git_attr *attr;
} u;
char is_macro;
unsigned num_attr;
struct attr_state state[FLEX_ARRAY];
};
static const char blank[] = " \t\r\n";
/*
* Parse a whitespace-delimited attribute state (i.e., "attr",
* "-attr", "!attr", or "attr=value") from the string starting at src.
* If e is not NULL, write the results to *e. Return a pointer to the
* remainder of the string (with leading whitespace removed), or NULL
* if there was an error.
*/
static const char *parse_attr(const char *src, int lineno, const char *cp,
struct attr_state *e)
{
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 (!e) {
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 {
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);
}
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, i;
const char *cp, *name, *states;
struct match_attr *res = NULL;
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 &&
starts_with(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;
states = name + namelen;
states += strspn(states, blank);
/* First pass to count the attr_states */
for (cp = states, num_attr = 0; *cp; num_attr++) {
cp = parse_attr(src, lineno, cp, NULL);
if (!cp)
return NULL;
}
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);
res->u.attr->maybe_macro = 1;
} else {
char *p = (char *)&(res->state[num_attr]);
memcpy(p, name, namelen);
res->u.pat.pattern = p;
parse_exclude_pattern(&res->u.pat.pattern,
&res->u.pat.patternlen,
&res->u.pat.flags,
&res->u.pat.nowildcardlen);
if (res->u.pat.flags & EXC_FLAG_NEGATIVE) {
warning(_("Negative patterns are ignored in git attributes\n"
"Use '\\!' for literal leading exclamation."));
return NULL;
}
}
res->is_macro = is_macro;
res->num_attr = num_attr;
/* Second pass to fill the attr_states */
for (cp = states, i = 0; *cp; i++) {
cp = parse_attr(src, lineno, cp, &(res->state[i]));
if (!is_macro)
res->state[i].attr->maybe_real = 1;
if (res->state[i].attr->maybe_macro)
cannot_trust_maybe_real = 1;
}
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 is_excluded() does in dir.c to deal with
* .gitignore
*/
static struct attr_stack {
struct attr_stack *prev;
char *origin;
size_t originlen;
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->attrs);
free(e);
}
static const char *builtin_attr[] = {
"[attr]binary -diff -merge -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;
ALLOC_GROW(res->attrs, res->num_matches + 1, 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) {
if (errno != ENOENT && errno != ENOTDIR)
warn_on_inaccessible(path);
return NULL;
}
res = xcalloc(1, sizeof(*res));
while (fgets(buf, sizeof(buf), fp)) {
char *bufp = buf;
if (!lineno)
skip_utf8_bom(&bufp, strlen(bufp));
handle_attr_line(res, bufp, path, ++lineno, macro_ok);
}
fclose(fp);
return res;
}
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_blob_data_from_index(use_index ? use_index : &the_index, path, NULL);
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 GIT_PATH_FUNC(git_path_info_attributes, INFOATTRIBUTES_FILE)
static void bootstrap_attr_stack(void)
{
struct attr_stack *elem;
if (attr_stack)
return;
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;
}
}
if (!git_attributes_file)
git_attributes_file = xdg_config_home("attributes");
if (git_attributes_file) {
elem = read_attr_from_file(git_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 = xstrdup("");
elem->originlen = 0;
elem->prev = attr_stack;
attr_stack = elem;
debug_push(elem);
}
elem = read_attr_from_file(git_path_info_attributes(), 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;
const char *cp;
/*
* 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.
*/
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. Break out of the loop when we see
* the root one (whose origin is an empty string "") or the builtin
* one (whose origin is NULL) without popping it.
*/
while (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) {
/*
* bootstrap_attr_stack() should have added, and the
* above loop should have stopped before popping, the
* root element whose attr_stack->origin is set to an
* empty string.
*/
struct strbuf pathbuf = STRBUF_INIT;
assert(attr_stack->origin);
while (1) {
len = strlen(attr_stack->origin);
if (dirlen <= len)
break;
cp = memchr(path + len + 1, '/', dirlen - len - 1);
if (!cp)
cp = path + dirlen;
strbuf_add(&pathbuf, path, cp - path);
strbuf_addch(&pathbuf, '/');
strbuf_addstr(&pathbuf, GITATTRIBUTES_FILE);
elem = read_attr(pathbuf.buf, 0);
strbuf_setlen(&pathbuf, cp - path);
elem->origin = strbuf_detach(&pathbuf, &elem->originlen);
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,
int basename_offset,
const struct pattern *pat,
const char *base, int baselen)
{
const char *pattern = pat->pattern;
int prefix = pat->nowildcardlen;
int isdir = (pathlen && pathname[pathlen - 1] == '/');
if ((pat->flags & EXC_FLAG_MUSTBEDIR) && !isdir)
return 0;
if (pat->flags & EXC_FLAG_NODIR) {
return match_basename(pathname + basename_offset,
pathlen - basename_offset - isdir,
pattern, prefix,
pat->patternlen, pat->flags);
}
return match_pathname(pathname, pathlen - isdir,
base, baselen,
pattern, prefix, pat->patternlen, pat->flags);
}
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.pat.pattern,
attr, v);
*n = v;
rem--;
rem = macroexpand_one(attr->attr_nr, rem);
}
}
return rem;
}
static int fill(const char *path, int pathlen, int basename_offset,
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, basename_offset,
&a->u.pat, base, stk->originlen))
rem = fill_one("fill", a, rem);
}
return rem;
}
static int macroexpand_one(int nr, int rem)
{
struct attr_stack *stk;
struct match_attr *a = NULL;
int i;
if (check_all_attr[nr].value != ATTR__TRUE ||
!check_all_attr[nr].attr->maybe_macro)
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 == nr)
a = ma;
}
if (a)
rem = fill_one("expand", a, rem);
return rem;
}
/*
* Collect attributes for path into the array pointed to by
* check_all_attr. If num is non-zero, only attributes in check[] are
* collected. Otherwise all attributes are collected.
*/
static void collect_some_attrs(const char *path, int num,
struct git_attr_check *check)
{
struct attr_stack *stk;
int i, pathlen, rem, dirlen;
const char *cp, *last_slash = NULL;
int basename_offset;
for (cp = path; *cp; cp++) {
if (*cp == '/' && cp[1])
last_slash = cp;
}
pathlen = cp - path;
if (last_slash) {
basename_offset = last_slash + 1 - path;
dirlen = last_slash - path;
} else {
basename_offset = 0;
dirlen = 0;
}
prepare_attr_stack(path, dirlen);
for (i = 0; i < attr_nr; i++)
check_all_attr[i].value = ATTR__UNKNOWN;
if (num && !cannot_trust_maybe_real) {
rem = 0;
for (i = 0; i < num; i++) {
if (!check[i].attr->maybe_real) {
struct git_attr_check *c;
c = check_all_attr + check[i].attr->attr_nr;
c->value = ATTR__UNSET;
rem++;
}
}
if (rem == num)
return;
}
rem = attr_nr;
for (stk = attr_stack; 0 < rem && stk; stk = stk->prev)
rem = fill(path, pathlen, basename_offset, stk, rem);
}
int git_check_attr(const char *path, int num, struct git_attr_check *check)
{
int i;
collect_some_attrs(path, num, check);
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;
}
int git_all_attrs(const char *path, int *num, struct git_attr_check **check)
{
int i, count, j;
collect_some_attrs(path, 0, NULL);
/* Count the number of attributes that are set. */
count = 0;
for (i = 0; i < attr_nr; i++) {
const char *value = check_all_attr[i].value;
if (value != ATTR__UNSET && value != ATTR__UNKNOWN)
++count;
}
*num = count;
ALLOC_ARRAY(*check, count);
j = 0;
for (i = 0; i < attr_nr; i++) {
const char *value = check_all_attr[i].value;
if (value != ATTR__UNSET && value != ATTR__UNKNOWN) {
(*check)[j].attr = check_all_attr[i].attr;
(*check)[j].value = value;
++j;
}
}
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;
}