src/document/css/apply.c

   1 /** CSS style applier
   2  * @file
   3  *
   4  * @todo TODO: A way to disable CSS completely, PLUS a way to stop
   5  * various property groups from taking effect. (Ie. way to turn out
   6  * effect of 'display: none' or aligning or colors but keeping all the
   7  * others.) --pasky */
   8
   9 #ifdef HAVE_CONFIG_H
  10 #include "config.h"
  11 #endif
  12
  13 #include <stdlib.h>
  14 #include <string.h>
  15
  16 #include "elinks.h"
  17
  18 #include "document/css/apply.h"
  19 #include "document/css/css.h"
  20 #include "document/css/parser.h"
  21 #include "document/css/property.h"
  22 #include "document/css/scanner.h"
  23 #include "document/css/stylesheet.h"
  24 #include "document/format.h"
  25 #include "document/html/parser/parse.h"
  26 #include "document/options.h"
  27 #include "util/align.h"
  28 #include "util/color.h"
  29 #include "util/lists.h"
  30 #include "util/error.h"
  31 #include "util/memory.h"
  32 #include "util/string.h"
  33
  34 /* XXX: Some strange dependency makes it necessary to this include last. */
  35 #include "document/html/internal.h"
  36
  37
  38 typedef void (*css_applier_T)(struct html_context *html_context,
  39                               struct html_element *element,
  40                               struct css_property *prop);
  41
  42 static void
  43 css_apply_color(struct html_context *html_context, struct html_element *element,
  44                 struct css_property *prop)
  45 {
  46         assert(prop->value_type == CSS_VT_COLOR);
  47
  48         if (use_document_fg_colors(html_context->options))
  49                 element->attr.style.color.foreground = prop->value.color;
  50 }
  51
  52 static void
  53 css_apply_background_color(struct html_context *html_context,
  54                            struct html_element *element,
  55                            struct css_property *prop)
  56 {
  57         assert(prop->value_type == CSS_VT_COLOR);
  58
  59         if (use_document_bg_colors(html_context->options))
  60                 element->attr.style.color.background = prop->value.color;
  61 }
  62
  63 static void
  64 css_apply_display(struct html_context *html_context, struct html_element *element,
  65                   struct css_property *prop)
  66 {
  67         assert(prop->value_type == CSS_VT_DISPLAY);
  68
  69         switch (prop->value.display) {
  70                 case CSS_DISP_INLINE:
  71                         element->linebreak = 0;
  72                         break;
  73                 case CSS_DISP_BLOCK:
  74                         /* 1 or 2, that is the question. I went for 2 since it
  75                          * gives a more "blocky" feel and it's more common.
  76                          * YMMV. */
  77                         element->linebreak = 2;
  78                         break;
  79                 case CSS_DISP_NONE:
  80                         if (!html_context->options->css_ignore_display_none)
  81                                 element->invisible = 2;
  82                         break;
  83                 default:
  84                         INTERNAL("Bad prop->value.display %d", prop->value.display);
  85                         break;
  86         }
  87 }
  88
  89 static void
  90 css_apply_font_attribute(struct html_context *html_context,
  91                          struct html_element *element, struct css_property *prop)
  92 {
  93         assert(prop->value_type == CSS_VT_FONT_ATTRIBUTE);
  94         element->attr.style.attr |= prop->value.font_attribute.add;
  95         element->attr.style.attr &= ~prop->value.font_attribute.rem;
  96 }
  97
  98 static void
  99 css_apply_list_style(struct html_context *html_context,
 100                      struct html_element *element, struct css_property *prop)
 101 {
 102         assert(prop->value_type == CSS_VT_LIST_STYLE);
 103
 104         element->parattr.list_number = (prop->value.list_style > CSS_LIST_ORDINAL);
 105         switch (prop->value.list_style) {
 106         case CSS_LIST_NONE: element->parattr.flags = P_NO_BULLET; break;
 107         case CSS_LIST_DISC: element->parattr.flags = P_DISC; break;
 108         case CSS_LIST_CIRCLE: element->parattr.flags = P_O; break;
 109         case CSS_LIST_SQUARE: element->parattr.flags = P_SQUARE; break;
 110         case CSS_LIST_DECIMAL: element->parattr.flags = P_NUMBER; break;
 111         case CSS_LIST_DECIMAL_LEADING_ZERO: element->parattr.flags = P_NUMBER; break;
 112         case CSS_LIST_LOWER_ROMAN: element->parattr.flags = P_roman; break;
 113         case CSS_LIST_UPPER_ROMAN: element->parattr.flags = P_ROMAN; break;
 114         case CSS_LIST_LOWER_ALPHA: element->parattr.flags = P_alpha; break;
 115         case CSS_LIST_UPPER_ALPHA: element->parattr.flags = P_ALPHA; break;
 116         case CSS_LIST_LOWER_GREEK: element->parattr.flags = P_roman; break;
 117         case CSS_LIST_LOWER_LATIN: element->parattr.flags = P_alpha; break;
 118         case CSS_LIST_UPPER_LATIN: element->parattr.flags = P_ALPHA; break;
 119         case CSS_LIST_HEBREW: element->parattr.flags = P_NUMBER; break;
 120         case CSS_LIST_ARMENIAN: element->parattr.flags = P_NUMBER; break;
 121         case CSS_LIST_GEORGIAN: element->parattr.flags = P_NUMBER; break;
 122         case CSS_LIST_CJK_IDEOGRAPHIC: element->parattr.flags = P_NUMBER; break;
 123         case CSS_LIST_HIRAGANA: element->parattr.flags = P_NUMBER; break;
 124         case CSS_LIST_KATAKANA: element->parattr.flags = P_NUMBER; break;
 125         case CSS_LIST_HIRAGANA_IROHA: element->parattr.flags = P_NUMBER; break;
 126         case CSS_LIST_KATAKANA_IROHA: element->parattr.flags = P_NUMBER; break;
 127         case CSS_LIST_ORDINAL: assert(0); break;
 128         }
 129 }
 130
 131 /** @bug FIXME: Because the current CSS doesn't provide reasonable
 132  * defaults for each HTML element this applier will cause bad
 133  * rendering of @<pre> tags. */
 134 static void
 135 css_apply_text_align(struct html_context *html_context,
 136                      struct html_element *element, struct css_property *prop)
 137 {
 138         assert(prop->value_type == CSS_VT_TEXT_ALIGN);
 139         element->parattr.align = prop->value.text_align;
 140 }
 141
 142 /*! XXX: Sort like the css_property_type */
 143 static const css_applier_T css_appliers[CSS_PT_LAST] = {
 144         /* CSS_PT_NONE */               NULL,
 145         /* CSS_PT_BACKGROUND */         css_apply_background_color,
 146         /* CSS_PT_BACKGROUND_COLOR */   css_apply_background_color,
 147         /* CSS_PT_COLOR */              css_apply_color,
 148         /* CSS_PT_DISPLAY */            css_apply_display,
 149         /* CSS_PT_FONT_STYLE */         css_apply_font_attribute,
 150         /* CSS_PT_FONT_WEIGHT */        css_apply_font_attribute,
 151         /* CSS_PT_LIST_STYLE */         css_apply_list_style,
 152         /* CSS_PT_TEXT_ALIGN */         css_apply_text_align,
 153         /* CSS_PT_TEXT_DECORATION */    css_apply_font_attribute,
 154         /* CSS_PT_WHITE_SPACE */        css_apply_font_attribute,
 155 };
 156
 157 /** This looks for a match in list of selectors. */
 158 static void
 159 examine_element(struct html_context *html_context, struct css_selector *base,
 160                 enum css_selector_type seltype, enum css_selector_relation rel,
 161                 struct css_selector_set *selectors,
 162                 struct html_element *element)
 163 {
 164         struct css_selector *selector;
 165
 166 #ifdef DEBUG_CSS
 167         /* Cannot use list_empty() inside the arglist of DBG() because
 168          * GCC 4.1 "warning: operation on `errfile' may be undefined"
 169          * breaks the build with -Werror.  */
 170         int dbg_has_leaves, dbg_has_properties;
 171
 172         DBG("examine_element(%p, %s, %d, %d, %p, %.*s);", html_context, base->name, seltype, rel, selectors, element->namelen, element->name);
 173 #define dbginfo(sel, type_, base) \
 174         dbg_has_leaves = !css_selector_set_empty(&sel->leaves), \
 175         dbg_has_properties = !list_empty(sel->properties), \
 176         DBG("Matched selector %s (rel %d type %d [m%d])! Children %p !!%d, props !!%d", sel->name, sel->relation, sel->type, sel->type == type_, &sel->leaves, dbg_has_leaves, dbg_has_properties)
 177 #else
 178 #define dbginfo(sel, type, base)
 179 #endif
 180
 181 #define process_found_selector(sel, type, base) \
 182         if (selector) { \
 183                 dbginfo(sel, type, base); \
 184                 merge_css_selectors(base, sel); \
 185                 /* Ancestor matches? */ \
 186                 if (sel->leaves.may_contain_rel_ancestor_or_parent \
 187                     && (LIST_OF(struct html_element) *) element->next \
 188                      != &html_context->stack) { \
 189                         struct html_element *ancestor; \
 190                         /* This is less effective than doing reverse iterations,
 191                          * first over sel->leaves and then over the HTML stack,
 192                          * which shines in the most common case where there are
 193                          * no CSR_ANCESTOR selector leaves. However we would
 194                          * have to duplicate the whole examine_element(), so if
 195                          * profiles won't show it really costs... */ \
 196                         for (ancestor = element->next; \
 197                              (LIST_OF(struct html_element) *) ancestor  \
 198                               != &html_context->stack;\
 199                              ancestor = ancestor->next) \
 200                                 examine_element(html_context, base, \
 201                                                 CST_ELEMENT, CSR_ANCESTOR, \
 202                                                 &sel->leaves, ancestor); \
 203                         examine_element(html_context, base, \
 204                                         CST_ELEMENT, CSR_PARENT, \
 205                                         &sel->leaves, element->next); \
 206                 } \
 207                 /* More specific matches? */ \
 208                 examine_element(html_context, base, type + 1, \
 209                                 CSR_SPECIFITY, \
 210                                 &sel->leaves, element); \
 211         }
 212
 213         if (seltype <= CST_ELEMENT && element->namelen) {
 214                 selector = find_css_selector(selectors, CST_ELEMENT, rel,
 215                                              "*", 1);
 216                 process_found_selector(selector, CST_ELEMENT, base);
 217
 218                 selector = find_css_selector(selectors, CST_ELEMENT, rel,
 219                                              element->name, element->namelen);
 220                 process_found_selector(selector, CST_ELEMENT, base);
 221         }
 222
 223         if (!element->options)
 224                 return;
 225
 226         /* TODO: More pseudo-classess. --pasky */
 227         if (element->pseudo_class & ELEMENT_LINK) {
 228                 selector = find_css_selector(selectors, CST_PSEUDO, rel, "link", -1);
 229                 process_found_selector(selector, CST_PSEUDO, base);
 230         }
 231         if (element->pseudo_class & ELEMENT_VISITED) {
 232                 selector = find_css_selector(selectors, CST_PSEUDO, rel, "visited", -1);
 233                 process_found_selector(selector, CST_PSEUDO, base);
 234         }
 235
 236         if (element->attr.class && seltype <= CST_CLASS) {
 237                 const unsigned char *class = element->attr.class;
 238
 239                 for (;;) {
 240                         const unsigned char *begin;
 241
 242                         while (*class == ' ') ++class;
 243                         if (*class == '\0') break;
 244                         begin = class;
 245                         while (*class != ' ' && *class != '\0') ++class;
 246
 247                         selector = find_css_selector(selectors, CST_CLASS, rel,
 248                                                      begin, class - begin);
 249                         process_found_selector(selector, CST_CLASS, base);
 250                 }
 251         }
 252
 253         if (element->attr.id && seltype <= CST_ID) {
 254                 selector = find_css_selector(selectors, CST_ID, rel, element->attr.id, -1);
 255                 process_found_selector(selector, CST_ID, base);
 256         }
 257
 258 #undef process_found_selector
 259 #undef dbginfo
 260 }
 261
 262 struct css_selector *
 263 get_css_selector_for_element(struct html_context *html_context,
 264                              struct html_element *element,
 265                              struct css_stylesheet *css,
 266                              LIST_OF(struct html_element) *html_stack)
 267 {
 268         unsigned char *code;
 269         struct css_selector *selector;
 270
 271         assert(element && element->options && css);
 272
 273         selector = init_css_selector(NULL, CST_ELEMENT, CSR_ROOT, NULL, 0);
 274         if (!selector)
 275                 return NULL;
 276
 277 #ifdef DEBUG_CSS
 278         DBG("Applying to element %.*s...", element->namelen, element->name);
 279 #endif
 280
 281         examine_element(html_context, selector, CST_ELEMENT, CSR_ROOT,
 282                         &css->selectors, element);
 283
 284 #ifdef DEBUG_CSS
 285         DBG("Element %.*s applied.", element->namelen, element->name);
 286 #endif
 287
 288         code = get_attr_val(element->options, "style", html_context->doc_cp);
 289         if (code) {
 290                 struct css_selector *stylesel;
 291                 struct scanner scanner;
 292
 293                 stylesel = init_css_selector(NULL, CST_ELEMENT, CSR_ROOT, NULL, 0);
 294
 295                 if (stylesel) {
 296                         init_scanner(&scanner, &css_scanner_info, code, NULL);
 297                         css_parse_properties(&stylesel->properties, &scanner);
 298                         merge_css_selectors(selector, stylesel);
 299                         done_css_selector(stylesel);
 300                 }
 301                 mem_free(code);
 302         }
 303
 304         return selector;
 305 }
 306
 307 void
 308 apply_css_selector_style(struct html_context *html_context,
 309                          struct html_element *element,
 310                          struct css_selector *selector)
 311 {
 312         struct css_property *property;
 313
 314         foreach (property, selector->properties) {
 315                 assert(property->type < CSS_PT_LAST);
 316                 /* We don't assert general prop->value_type here because I
 317                  * don't want hinder properties' ability to potentially make
 318                  * use of multiple value types. */
 319                 assert(css_appliers[property->type]);
 320                 css_appliers[property->type](html_context, element, property);
 321         }
 322 }
 323
 324 void
 325 css_apply(struct html_context *html_context, struct html_element *element,
 326           struct css_stylesheet *css, LIST_OF(struct html_element) *html_stack)
 327 {
 328         struct css_selector *selector;
 329
 330         selector = get_css_selector_for_element(html_context, element, css,
 331                                                 html_stack);
 332         if (!selector) return;
 333
 334         apply_css_selector_style(html_context, element, selector);
 335
 336         done_css_selector(selector);
 337 }