diff options
Diffstat (limited to 'attr.c')
| -rw-r--r-- | attr.c | 823 |
1 files changed, 823 insertions, 0 deletions
diff --git a/attr.c b/attr.c new file mode 100644 index 0000000000..1f9eebd2dd --- /dev/null +++ b/attr.c @@ -0,0 +1,823 @@ +/* + * 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" + +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; + + 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++; + 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)) + handle_attr_line(res, buf, 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 void bootstrap_attr_stack(void) +{ + struct attr_stack *elem; + char *xdg_attributes_file; + + 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) { + home_config_paths(NULL, &xdg_attributes_file, "attributes"); + git_attributes_file = xdg_attributes_file; + } + 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(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; + 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; + *check = xmalloc(sizeof(**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; +} |