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-rw-r--r--attr.c380
1 files changed, 380 insertions, 0 deletions
diff --git a/attr.c b/attr.c
new file mode 100644
index 0000000..7435d92
--- /dev/null
+++ b/attr.c
@@ -0,0 +1,380 @@
+#include "cache.h"
+#include "attr.h"
+
+/*
+ * 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;
+ char name[FLEX_ARRAY];
+};
+
+static struct git_attr *(git_attr_hash[HASHSIZE]);
+
+static unsigned hash_name(const char *name, int namelen)
+{
+ unsigned val = 0;
+ unsigned char c;
+
+ while (namelen--) {
+ c = *name++;
+ val = ((val << 7) | (val >> 22)) ^ c;
+ }
+ return val;
+}
+
+struct git_attr *git_attr(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;
+ }
+
+ a = xmalloc(sizeof(*a) + len + 1);
+ memcpy(a->name, name, len);
+ a->name[len] = 0;
+ a->h = hval;
+ a->next = git_attr_hash[pos];
+ git_attr_hash[pos] = a;
+ return a;
+}
+
+/*
+ * .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 "not set".
+ */
+
+struct attr_state {
+ int unset;
+ struct git_attr *attr;
+};
+
+struct match_attr {
+ char *pattern;
+ unsigned num_attr;
+ struct attr_state state[FLEX_ARRAY];
+};
+
+static const char blank[] = " \t\r\n";
+
+static struct match_attr *parse_attr_line(const char *line)
+{
+ int namelen;
+ int num_attr;
+ const char *cp, *name;
+ struct match_attr *res = res;
+ int pass;
+
+ cp = line + strspn(line, blank);
+ if (!*cp || *cp == '#')
+ return NULL;
+ name = cp;
+ namelen = strcspn(name, blank);
+
+ 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) {
+ const char *ep;
+ ep = cp + strcspn(cp, blank);
+ if (pass) {
+ struct attr_state *e;
+
+ e = &(res->state[num_attr]);
+ if (*cp == '!') {
+ e->unset = 1;
+ cp++;
+ }
+ e->attr = git_attr(cp, ep - cp);
+ }
+ num_attr++;
+ cp = ep + strspn(ep, blank);
+ }
+ if (pass)
+ break;
+ res = xcalloc(1,
+ sizeof(*res) +
+ sizeof(struct attr_state) * num_attr +
+ namelen + 1);
+ res->pattern = (char*)&(res->state[num_attr]);
+ memcpy(res->pattern, name, namelen);
+ res->pattern[namelen] = 0;
+ 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) perhaps $GIT_DIR/info/attributes, as the final fallback.
+ *
+ * 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;
+ 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++)
+ free(e->attrs[i]);
+ free(e);
+}
+
+static const char *builtin_attr[] = {
+ NULL,
+};
+
+static struct attr_stack *read_attr_from_array(const char **list)
+{
+ struct attr_stack *res;
+ const char *line;
+
+ res = xcalloc(1, sizeof(*res));
+ while ((line = *(list++)) != NULL) {
+ struct match_attr *a = parse_attr_line(line);
+ if (!a)
+ continue;
+ res->attrs = xrealloc(res->attrs, res->num_matches + 1);
+ res->attrs[res->num_matches++] = a;
+ }
+ return res;
+}
+
+static struct attr_stack *read_attr_from_file(const char *path)
+{
+ FILE *fp;
+ struct attr_stack *res;
+ char buf[2048];
+
+ res = xcalloc(1, sizeof(*res));
+ fp = fopen(path, "r");
+ if (!fp)
+ return res;
+
+ while (fgets(buf, sizeof(buf), fp)) {
+ struct match_attr *a = parse_attr_line(buf);
+ if (!a)
+ continue;
+ res->attrs = xrealloc(res->attrs, res->num_matches + 1);
+ res->attrs[res->num_matches++] = a;
+ }
+ fclose(fp);
+ 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 : "()");
+}
+#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)
+#endif
+
+static void prepare_attr_stack(const char *path, int dirlen)
+{
+ struct attr_stack *elem, *info;
+ int len;
+ char pathbuf[PATH_MAX];
+
+ /*
+ * At the bottom of the attribute stack is the built-in
+ * set of attribute definitions. 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) {
+ elem = read_attr_from_array(builtin_attr);
+ elem->origin = NULL;
+ elem->prev = attr_stack;
+ attr_stack = elem;
+
+ elem = read_attr_from_file(GITATTRIBUTES_FILE);
+ elem->origin = strdup("");
+ elem->prev = attr_stack;
+ attr_stack = elem;
+ debug_push(elem);
+
+ elem = read_attr_from_file(git_path(INFOATTRIBUTES_FILE));
+ elem->origin = NULL;
+ elem->prev = attr_stack;
+ attr_stack = elem;
+ }
+
+ /*
+ * 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))
+ break;
+
+ debug_pop(elem);
+ attr_stack = elem->prev;
+ free_attr_elem(elem);
+ }
+
+ /*
+ * Read from parent directories and push them down
+ */
+ while (1) {
+ char *cp;
+
+ len = strlen(attr_stack->origin);
+ if (dirlen <= len)
+ break;
+ memcpy(pathbuf, path, dirlen);
+ memcpy(pathbuf + dirlen, "/", 2);
+ cp = strchr(pathbuf + len + 1, '/');
+ strcpy(cp + 1, GITATTRIBUTES_FILE);
+ elem = read_attr_from_file(pathbuf);
+ *cp = '\0';
+ elem->origin = strdup(pathbuf);
+ elem->prev = attr_stack;
+ attr_stack = elem;
+ debug_push(elem);
+ }
+
+ /*
+ * 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 - 1] != '/') ||
+ strncmp(pathname, base, baselen))
+ return 0;
+ return fnmatch(pattern, pathname + baselen, FNM_PATHNAME) == 0;
+}
+
+/*
+ * I do not like this at all. Only because we allow individual
+ * attribute to be set or unset incrementally by individual
+ * lines in .gitattribute files, we need to do this triple
+ * loop which looks quite wasteful.
+ */
+static int fill(const char *path, int pathlen,
+ struct attr_stack *stk, struct git_attr_check *check,
+ int num, int rem)
+{
+ int i, j, k;
+ 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 (path_matches(path, pathlen,
+ a->pattern, base, strlen(base))) {
+ for (j = 0; j < a->num_attr; j++) {
+ struct git_attr *attr = a->state[j].attr;
+ int set = !a->state[j].unset;
+ for (k = 0; k < num; k++) {
+ if (0 <= check[k].isset ||
+ check[k].attr != attr)
+ continue;
+ check[k].isset = set;
+ 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;
+
+ for (i = 0; i < num; i++)
+ check[i].isset = -1;
+
+ pathlen = strlen(path);
+ cp = strrchr(path, '/');
+ if (!cp)
+ dirlen = 0;
+ else
+ dirlen = cp - path;
+ prepare_attr_stack(path, dirlen);
+ rem = num;
+ for (stk = attr_stack; 0 < rem && stk; stk = stk->prev)
+ rem = fill(path, pathlen, stk, check, num, rem);
+ return 0;
+}
generated by cgit v0.10.2-6-g49f6 at 2024-04-19 22:33:15 (GMT)