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#include <stdio.h>
#include <stdlib.h>
#include <stdbool.h>
#include <string.h>
#include <assert.h>
#include "filter.h"
struct filter_rule parse_exclude_rule(const char *rule) {
const size_t len = strlen(rule);
const bool open_left = rule[0] == '*';
if (open_left) {
if (len < 4 || memcmp(rule, "**/", 3) != 0) {
fprintf(stderr, "Error: A filter rule starting with '*' must start with '**/'.\n");
exit(1);
}
} else {
if (rule[0] != '/') {
fprintf(stderr, "Error: A filter rule with a non-wildcard left-hand side must start with '/'.\n");
exit(1);
}
}
const bool open_right = len > 0 && rule[len - 1] == '*';
if (open_right) {
if (len < 4 || memcmp(rule + len - 3, "/**", 3) != 0) {
fprintf(stderr, "Error: A filter rule ending with '*' must end with '/**'.\n");
exit(1);
}
}
const size_t str_start = open_left ? 3 : 1;
const size_t str_len = len - str_start - (open_right ? 3 : 0);
for (size_t i = 0; i < str_len; i++) {
if (rule[str_start + i] == '*') {
fprintf(stderr, "Error: Wildcards in the middle of a pattern unsupported.\n");
exit(1);
}
}
char *str = malloc(str_len + 1);
memcpy(str, rule + str_start, str_len);
str[str_len] = '\0';
return (struct filter_rule){
.ftype = FILTER_EXCLUDE,
.ptype = open_left && open_right ? PATTERN_INFIX
: open_left ? PATTERN_SUFFIX
: open_right ? PATTERN_PREFIX
: PATTERN_EQUAL,
.str = str,
.len = str_len,
};
}
bool filter_rule_allows(const struct filter_rule rule, const char *path) {
assert(rule.ftype == FILTER_EXCLUDE);
switch (rule.ptype) {
case PATTERN_EQUAL:
if (strcmp(path, rule.str) == 0) return false;
break;
case PATTERN_PREFIX:
if (strncmp(path, rule.str, rule.len) == 0 &&
(path[rule.len] == '/' || path[rule.len] == '\0'))
return false;
break;
case PATTERN_SUFFIX: {
const size_t pathlen = strlen(path);
if (pathlen >= rule.len &&
memcmp(path + pathlen - rule.len, rule.str, rule.len) == 0 &&
(pathlen == rule.len || path[pathlen - rule.len - 1] == '/'))
return false;
break;
}
case PATTERN_INFIX: {
const size_t pathlen = strlen(path);
if (strncmp(path, rule.str, rule.len) == 0 &&
(path[rule.len] == '\0' || path[rule.len] == '/')) return false;
for (size_t i = 0; i < pathlen; i++) {
if (path[i] == '/') {
if (strncmp(path + i+1, rule.str, rule.len) == 0 &&
(path[i+1 + rule.len] == '\0' || path[i+1 + rule.len] == '/')) return false;
}
}
break;
}
}
return true;
}
void filter_rule_debugdump(FILE *stream, const struct filter_rule rule) {
const char *ftype_str;
switch (rule.ftype) {
case FILTER_EXCLUDE: ftype_str = "exclude"; break;
default: ftype_str = "?unknown_ftype"; break;
}
const char *ptype_str;
switch (rule.ptype) {
case PATTERN_EQUAL: ptype_str = "equal"; break;
case PATTERN_PREFIX: ptype_str = "prefix"; break;
case PATTERN_SUFFIX: ptype_str = "suffix"; break;
case PATTERN_INFIX: ptype_str = "infix"; break;
default: ptype_str = "?unknown_ptype"; break;
}
fprintf(stream, "%s %s <%s>\n", ftype_str, ptype_str, rule.str);
}
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