src/document/css/css.c

   1 /** CSS module management
   2  * @file */
   3
   4 #ifdef HAVE_CONFIG_H
   5 #include "config.h"
   6 #endif
   7
   8 #include <stdlib.h>
   9
  10 #include "elinks.h"
  11
  12 #include "cache/cache.h"
  13 #include "config/home.h"
  14 #include "config/options.h"
  15 #include "document/css/css.h"
  16 #include "document/css/parser.h"
  17 #include "document/css/stylesheet.h"
  18 #include "encoding/encoding.h"
  19 #include "intl/gettext/libintl.h"
  20 #include "main/module.h"
  21 #include "network/connection.h"
  22 #include "protocol/uri.h"
  23 #include "session/session.h"
  24 #include "util/error.h"
  25 #include "util/memory.h"
  26 #include "viewer/text/draw.h"
  27
  28
  29 union option_info css_options_info[] = {
  30         INIT_OPT_TREE("document", N_("Cascading Style Sheets"),
  31                 "css", OPT_SORT,
  32                 N_("Options concerning how to use CSS for styling "
  33                 "documents.")),
  34
  35         INIT_OPT_BOOL("document.css", N_("Enable CSS"),
  36                 "enable", 0, 1,
  37                 N_("Enable adding of CSS style info to documents.")),
  38
  39         INIT_OPT_BOOL("document.css", N_("Ignore \"display: none\""),
  40                 "ignore_display_none", 0, 1,
  41                 N_("When enabled, elements are rendered, even when their "
  42                 "display property has the value \"none\". Because ELinks's "
  43                 "CSS support is still very incomplete, this setting can "
  44                 "improve the way that some documents are rendered.")),
  45
  46         INIT_OPT_BOOL("document.css", N_("Import external style sheets"),
  47                 "import", 0, 1,
  48                 N_("When enabled any external style sheets that are imported "
  49                 "from either CSS itself using the @import keyword or from the "
  50                 "HTML using <link> tags in the document header will also be "
  51                 "downloaded.")),
  52
  53         INIT_OPT_STRING("document.css", N_("Default style sheet"),
  54                 "stylesheet", 0, "",
  55                 N_("The path to the file containing the default user defined "
  56                 "Cascading Style Sheet. It can be used to control the basic "
  57                 "layout of HTML documents. The path is assumed to be relative "
  58                 "to ELinks' home directory.\n"
  59                 "\n"
  60                 "Leave as \"\" to use built-in document styling.")),
  61
  62         INIT_OPT_STRING("document.css", N_("Media types"),
  63                 "media", 0, "tty",
  64                 N_("CSS media types that ELinks claims to support, separated "
  65                 "with commas. The \"all\" type is implied. Currently, only "
  66                 "ASCII characters work reliably here.  See CSS2 section 7: "
  67                 "http://www.w3.org/TR/1998/REC-CSS2-19980512/media.html")),
  68
  69         NULL_OPTION_INFO,
  70 };
  71
  72
  73 /** Check whether ELinks claims to support a specific CSS media type.
  74  *
  75  * @param optstr
  76  *   Null-terminated value of the document.css.media option.
  77  * @param token
  78  *   A name parsed from a CSS file or from an HTML media attribute.
  79  *   Need not be null-terminated.
  80  * @param token_length
  81  *   Length of @a token, in bytes.
  82  *
  83  * Both strings should be in the ASCII charset.
  84  *
  85  * @return nonzero if the media type is supported, 0 if not.  */
  86 int
  87 supports_css_media_type(const unsigned char *optstr,
  88                         const unsigned char *token, size_t token_length)
  89 {
  90         /* Split @optstr into comma-delimited strings, strip leading
  91          * and trailing spaces from each, and compare them to the
  92          * token.  */
  93         while (*optstr != '\0') {
  94                 const unsigned char *beg, *end;
  95
  96                 while (*optstr == ' ')
  97                         ++optstr;
  98
  99                 beg = optstr;
 100                 optstr += strcspn(optstr, ",");
 101                 end = optstr;
 102                 while (end > beg && end[-1] == ' ')
 103                         --end;
 104
 105                 /* W3C REC-html401-19991224 section 6.13:
 106                  *   "3. A case-sensitive match is then made with
 107                  *    the set of media types defined above."
 108                  * W3C REC-html401-19991224 section 14.2.3:
 109                  *   "media = media-descriptors [CI]"
 110                  *   where CI stands for case-insensitive.
 111                  * This mismatch has been reported to the
 112                  * www-html-editor@w3.org mailing list on 2000-11-16.
 113                  *
 114                  * W3C REC-CSS2-19980512 section 7.3:
 115                  *  "Media type names are case-insensitive."  */
 116                 if (!strlcasecmp(token, token_length, beg, end - beg))
 117                         return 1;
 118
 119                 while (*optstr == ',')
 120                         ++optstr;
 121         }
 122
 123         /* An explicit "all" is probably rarer than e.g. "tty".  */
 124         if (!strlcasecmp(token, token_length, "all", 3))
 125                 return 1;
 126
 127         return 0;
 128 }
 129
 130 void
 131 import_css(struct css_stylesheet *css, struct uri *uri)
 132 {
 133         /* Do we have it in the cache? (TODO: CSS cache) */
 134         struct cache_entry *cached;
 135         struct fragment *fragment;
 136
 137         if (!uri || css->import_level >= MAX_REDIRECTS)
 138                 return;
 139
 140         cached = get_redirected_cache_entry(uri);
 141         if (!cached) return;
 142
 143         fragment = get_cache_fragment(cached);
 144         if (fragment) {
 145                 unsigned char *end = fragment->data + fragment->length;
 146
 147                 css->import_level++;
 148                 css_parse_stylesheet(css, uri, fragment->data, end);
 149                 css->import_level--;
 150         }
 151 }
 152
 153
 154 static void
 155 import_css_file(struct css_stylesheet *css, struct uri *base_uri,
 156                 const unsigned char *url, int urllen)
 157 {
 158         struct string string, filename;
 159
 160         if (!*url
 161             || css->import_level >= MAX_REDIRECTS
 162             || !init_string(&filename))
 163                 return;
 164
 165         if (*url != '/' && elinks_home) {
 166                 add_to_string(&filename, elinks_home);
 167         }
 168
 169         add_bytes_to_string(&filename, url, urllen);
 170
 171         if (is_in_state(read_encoded_file(&filename, &string), S_OK)) {
 172                 unsigned char *end = string.source + string.length;
 173
 174                 css->import_level++;
 175                 css_parse_stylesheet(css, base_uri, string.source, end);
 176                 done_string(&string);
 177                 css->import_level--;
 178         }
 179
 180         done_string(&filename);
 181 }
 182
 183 struct css_stylesheet default_stylesheet = INIT_CSS_STYLESHEET(default_stylesheet, import_css_file);
 184
 185 static void
 186 import_default_css(void)
 187 {
 188         unsigned char *url = get_opt_str("document.css.stylesheet", NULL);
 189
 190         if (!css_selector_set_empty(&default_stylesheet.selectors))
 191                 done_css_stylesheet(&default_stylesheet);
 192
 193         if (!*url) return;
 194
 195         import_css_file(&default_stylesheet, NULL, url, strlen(url));
 196 }
 197
 198 static int
 199 change_hook_css(struct session *ses, struct option *current, struct option *changed)
 200 {
 201         int reload_css = 0;
 202
 203         if (!strcmp(changed->name, "stylesheet")) {
 204                 /** @todo TODO: We need to update all entries in
 205                  * format cache. --jonas */
 206                 import_default_css();
 207         }
 208
 209         if (!strcmp(changed->name, "media"))
 210                 reload_css = 1;
 211
 212         /* Instead of using the value of the @ses parameter, iterate
 213          * through the @sessions list.  The parameter may be NULL and
 214          * anyway we don't support session-specific options yet.  */
 215         foreach (ses, sessions) draw_formatted(ses, 1 + reload_css);
 216
 217         return 0;
 218 }
 219
 220 static void
 221 init_css(struct module *module)
 222 {
 223         static const struct change_hook_info css_change_hooks[] = {
 224                 { "document.css",               change_hook_css },
 225                 { NULL,                         NULL },
 226         };
 227
 228         register_change_hooks(css_change_hooks);
 229         import_default_css();
 230 }
 231
 232 void
 233 done_css(struct module *module)
 234 {
 235         done_css_stylesheet(&default_stylesheet);
 236 }
 237
 238
 239 struct module css_module = struct_module(
 240         /* name: */             N_("Cascading Style Sheets"),
 241         /* options: */          css_options_info,
 242         /* hooks: */            NULL,
 243         /* submodules: */       NULL,
 244         /* data: */             NULL,
 245         /* init: */             init_css,
 246         /* done: */             done_css
 247 );