| 145 | } |
| 146 | |
| 147 | string CleanPath(StringPiece unclean_path) { |
| 148 | string path(unclean_path); |
| 149 | const char* src = path.c_str(); |
| 150 | string::iterator dst = path.begin(); |
| 151 | |
| 152 | // Check for absolute path and determine initial backtrack limit. |
| 153 | const bool is_absolute_path = *src == '/'; |
| 154 | if (is_absolute_path) { |
| 155 | *dst++ = *src++; |
| 156 | while (*src == '/') ++src; |
| 157 | } |
| 158 | string::const_iterator backtrack_limit = dst; |
| 159 | |
| 160 | // Process all parts |
| 161 | while (*src) { |
| 162 | bool parsed = false; |
| 163 | |
| 164 | if (src[0] == '.') { |
| 165 | // 1dot ".<whateverisnext>", check for END or SEP. |
| 166 | if (src[1] == '/' || !src[1]) { |
| 167 | if (*++src) { |
| 168 | ++src; |
| 169 | } |
| 170 | parsed = true; |
| 171 | } else if (src[1] == '.' && (src[2] == '/' || !src[2])) { |
| 172 | // 2dot END or SEP (".." | "../<whateverisnext>"). |
| 173 | src += 2; |
| 174 | if (dst != backtrack_limit) { |
| 175 | // We can backtrack the previous part |
| 176 | for (--dst; dst != backtrack_limit && dst[-1] != '/'; --dst) { |
| 177 | // Empty. |
| 178 | } |
| 179 | } else if (!is_absolute_path) { |
| 180 | // Failed to backtrack and we can't skip it either. Rewind and copy. |
| 181 | src -= 2; |
| 182 | *dst++ = *src++; |
| 183 | *dst++ = *src++; |
| 184 | if (*src) { |
| 185 | *dst++ = *src; |
| 186 | } |
| 187 | // We can never backtrack over a copied "../" part so set new limit. |
| 188 | backtrack_limit = dst; |
| 189 | } |
| 190 | if (*src) { |
| 191 | ++src; |
| 192 | } |
| 193 | parsed = true; |
| 194 | } |
| 195 | } |
| 196 | |
| 197 | // If not parsed, copy entire part until the next SEP or EOS. |
| 198 | if (!parsed) { |
| 199 | while (*src && *src != '/') { |
| 200 | *dst++ = *src++; |
| 201 | } |
| 202 | if (*src) { |
| 203 | *dst++ = *src++; |
| 204 | } |