src/svgtiny_parse.c: add svgtiny_parse_style_inline() function

This function parses the contents of an inline style="..." attribute
into a libcss stylesheet, or NULL if anything went wrong.

We use the new function in svgtiny_parse_paint_attributes() to parse
an inline sheet... and then (for now) do nothing with it. We are able
to parse the inline style="..." attributes right now but more
scaffolding is needed before we can utilize css_select_style().

diff --git a/src/svgtiny_parse.c b/src/svgtiny_parse.c
index af7b2287d43452ecc85c9c5c479bda1243e297ac..566a8c03affffbeef399701cbece87f76c32facf 100644 (file)
--- a/src/svgtiny_parse.c
+++ b/src/svgtiny_parse.c
@@ -10,6 +10,7 @@
 #include <float.h>
 #include <string.h>
 
+#include <libcss/libcss.h>
 
 #include "svgtiny.h"
 #include "svgtiny_internal.h"
@@ -1489,6 +1490,38 @@ svgtiny_parse_viewbox(const char *text,
 }
 
 
+/**
+ * Parse the contents of an inline style and return (a pointer to) the
+ * corresponding stylesheet for use with css_select_style(). Returns
+ * NULL if anything goes wrong.
+ */
+static css_stylesheet *svgtiny_parse_style_inline(const uint8_t *data,
+               size_t len)
+{
+       css_stylesheet *sheet;
+       css_error code;
+
+       code = svgtiny_create_stylesheet(&sheet, true);
+       if (code != CSS_OK) {
+               return NULL;
+       }
+
+       code = css_stylesheet_append_data(sheet, data, len);
+       if (code != CSS_OK && code != CSS_NEEDDATA) {
+               css_stylesheet_destroy(sheet);
+               return NULL;
+       }
+
+       code = css_stylesheet_data_done(sheet);
+       if (code != CSS_OK) {
+               css_stylesheet_destroy(sheet);
+               return NULL;
+       }
+
+       return sheet;
+}
+
+
 /**
  * parse an inline style
  */
@@ -1503,6 +1536,13 @@ svgtiny_parse_inline_style(dom_element *node,
        dom_string *attr;
        dom_exception exc;
 
+       /* We store the result of svgtiny_parse_style_inline() in
+        * inline_sheet, and that function returns NULL on error; in
+        * particular you do not need to css_stylesheet_destroy() the
+        * result if it is NULL. We initialize inline_sheet to NULL to
+        * retain the same semantics. */
+       css_stylesheet *inline_sheet = NULL;
+
        /* style attribute */
        exc = dom_element_get_attribute(node, state->interned_style, &attr);
        if (exc != DOM_NO_ERR) {
@@ -1512,6 +1552,14 @@ svgtiny_parse_inline_style(dom_element *node,
                /* no style attribute */
                return svgtiny_OK;
        }
+       /* First parse the style attribute into a libcss stylesheet
+          in case any of its properties are known to libcss. */
+       inline_sheet = svgtiny_parse_style_inline(
+                                         (uint8_t *)dom_string_data(attr),
+                                         dom_string_byte_length(attr));
+
+       /* Parse any other properties "by hand" until they can
+          be supported in libcss. */
        cursor = dom_string_data(attr);
        textend = cursor + dom_string_byte_length(attr);
 
@@ -1529,6 +1577,11 @@ svgtiny_parse_inline_style(dom_element *node,
                cursor++; /* skip semicolon */
        }
        dom_string_unref(attr);
+
+       if (inline_sheet != NULL) {
+               css_stylesheet_destroy(inline_sheet);
+       }
+
        return svgtiny_OK;
 }