src/svgtiny_css.c

   1 #include <libcss/libcss.h>
   2
   3 #include "svgtiny.h"
   4 #include "svgtiny_internal.h"
   5
   6 static css_error node_name(void *pw, void *node, css_qname *qname);
   7 static css_error node_classes(void *pw, void *node,
   8                 lwc_string ***classes, uint32_t *n_classes);
   9 static css_error node_id(void *pw, void *node, lwc_string **id);
  10
  11
  12 /**
  13  * Resolve a relative URL to an absolute one by doing nothing. This is
  14  * the simplest possible implementation of a URL resolver, needed for
  15  * parsing CSS.
  16  */
  17 css_error svgtiny_resolve_url(void *pw,
  18                 const char *base, lwc_string *rel, lwc_string **abs)
  19 {
  20         UNUSED(pw);
  21         UNUSED(base);
  22
  23         /* Copy the relative URL to the absolute one (the return
  24            value) */
  25         *abs = lwc_string_ref(rel);
  26         return CSS_OK;
  27 }
  28
  29 /**
  30  * Create a stylesheet with the default set of params.
  31  *
  32  * \param sheet A stylesheet pointer, passed in by reference, that
  33  * we use to store the newly-created stylesheet.
  34  * \param inline_style True if this stylesheet represents an inline
  35  * style, and false otherwise.
  36  *
  37  * \return The return value from css_stylesheet_create() is returned.
  38  */
  39 css_error svgtiny_create_stylesheet(css_stylesheet **sheet,
  40                 bool inline_style)
  41 {
  42         css_stylesheet_params params;
  43
  44         params.params_version = CSS_STYLESHEET_PARAMS_VERSION_1;
  45         params.level = CSS_LEVEL_DEFAULT;
  46         params.charset = NULL;
  47         params.url = "";
  48         params.title = NULL;
  49         params.allow_quirks = false;
  50         params.inline_style = inline_style;
  51         params.resolve = svgtiny_resolve_url;
  52         params.resolve_pw = NULL;
  53         params.import = NULL;
  54         params.import_pw = NULL;
  55         params.color = NULL;
  56         params.color_pw = NULL;
  57         params.font = NULL;
  58         params.font_pw = NULL;
  59
  60         return css_stylesheet_create(&params, sheet);
  61 }
  62
  63
  64 /**************************/
  65 /* libcss select handlers */
  66 /**************************/
  67 /*
  68  * From here on we implement the "select handler "API defined in
  69  * libcss's include/libcss/select.h and discussed briefly in its
  70  * docs/API document.
  71  */
  72
  73
  74 /**
  75  * Retrieve the given node's name
  76  *
  77  * \param pw     Pointer to the current SVG parser state
  78  * \param node   Libdom SVG node
  79  * \param qname  Address at which to store the node name
  80  *
  81  * \return CSS_OK on success, or CSS_NOMEM if anything goes wrong
  82  */
  83 css_error node_name(void *pw, void *node, css_qname *qname)
  84 {
  85         dom_string *name;
  86         dom_exception err;
  87         struct svgtiny_parse_state *state;
  88
  89         err = dom_node_get_node_name((dom_node *)node, &name);
  90         if (err != DOM_NO_ERR) {
  91                 return CSS_NOMEM;
  92         }
  93
  94         state = (struct svgtiny_parse_state *)pw;
  95         qname->ns = lwc_string_ref(state->interned_svg_xmlns);
  96
  97         err = dom_string_intern(name, &qname->name);
  98         if (err != DOM_NO_ERR) {
  99                 dom_string_unref(name);
 100                 return CSS_NOMEM;
 101         }
 102
 103         dom_string_unref(name);
 104
 105         return CSS_OK;
 106 }
 107
 108
 109 /**
 110  * Retrieve the given node's classes
 111  *
 112  * \param pw         Pointer to the current SVG parser state
 113  * \param node       Libdom SVG node
 114  * \param classes    Address at which to store the class name array
 115  * \param n_classes  Address at which to store the length of the class
 116  *                   name array
 117  *
 118  * \return CSS_OK on success, or CSS_NOMEM if anything goes wrong
 119  *
 120  * \note CSS_NOMEM is not possible in practice as of libdom-0.4.1,
 121  *       because the underlying libdom function never fails
 122  */
 123 css_error node_classes(void *pw, void *node,
 124                 lwc_string ***classes, uint32_t *n_classes)
 125 {
 126         UNUSED(pw);
 127         dom_exception err;
 128
 129         err = dom_element_get_classes((dom_node *)node, classes, n_classes);
 130
 131         /* The implementation does not do it, but the documentation
 132            for dom_element_get_classes() says that a DOM_NO_MEM_ERR is
 133            possible here, so we handle it to be on the safe side. */
 134         if (err != DOM_NO_ERR) {
 135                 return CSS_NOMEM;
 136         }
 137
 138         return CSS_OK;
 139 }
 140
 141
 142 /**
 143  * Retrieve the given node's id
 144  *
 145  * \param pw    Pointer to the current SVG parser state
 146  * \param node  Libdom SVG node
 147  * \param id    Address at which to store the id
 148  *
 149  * \return      CSS_OK on success, or CSS_NOMEM if anything goes wrong
 150  */
 151 css_error node_id(void *pw, void *node, lwc_string **id)
 152 {
 153         dom_string *attr;
 154         dom_exception err;
 155         struct svgtiny_parse_state *state;
 156
 157         /* Begin with the assumption that this node has no id */
 158         *id = NULL;
 159
 160         state = (struct svgtiny_parse_state *)pw;
 161         err = dom_element_get_attribute((dom_node *)node,
 162                                         state->interned_id, &attr);
 163         if (err != DOM_NO_ERR) {
 164                 return CSS_NOMEM;
 165         }
 166         else if (attr == NULL) {
 167                 /* The node has no id attribute and our return value
 168                    is already set to NULL so we're done */
 169                 return CSS_OK;
 170         }
 171
 172         /* If we found an id attribute (a dom_string), intern it into
 173            an lwc_string that we can return, and then cleanup the
 174            dom_string. */
 175         err = dom_string_intern(attr, id);
 176         if (err != DOM_NO_ERR) {
 177                 dom_string_unref(attr);
 178                 return CSS_NOMEM;
 179         }
 180         dom_string_unref(attr);
 181         return CSS_OK;
 182 }