X-Git-Url: http://gitweb.michael.orlitzky.com/?a=blobdiff_plain;f=src%2Fsvgtiny_css.c;h=fec0ed4a4596006148585662913b64bbf7a0a965;hb=a90ff2fb192c68d1a380b59b55b394cee57c7ee1;hp=80d4de1ef327f5fadeb3fef6d3b24c4ac81323b5;hpb=d89d98c07001fc6fc54b1bd9be7eaa3ca64b6294;p=libsvgtiny.git

diff --git a/src/svgtiny_css.c b/src/svgtiny_css.c
index 80d4de1..fec0ed4 100644
--- a/src/svgtiny_css.c
+++ b/src/svgtiny_css.c
@@ -43,6 +43,10 @@ static css_error node_has_attribute_substring(void *pw, void *node,
 		const css_qname *qname, lwc_string *substring,
 		bool *match);
 static css_error node_is_root(void *pw, void *node, bool *match);
+static css_error node_count_siblings(void *pw, void *node,
+		bool same_name, bool after, int32_t *count);
+static css_error node_is_empty(void *pw, void *node, bool *is_empty);
+static css_error node_is_link(void *pw, void *node, bool *is_link);
 
 
 /**
@@ -1232,3 +1236,249 @@ css_error node_is_root(void *pw, void *node, bool *match)
 	*match = true;
 	return CSS_OK;
 }
+
+
+/**
+ * Used internally in node_count_siblings() to "count" the given
+ * sibling node. It factors out the node type and name checks.
+ */
+static int node_count_siblings_check(dom_node *dnode,
+		bool check_name,
+		dom_string *name)
+{
+	int ret;
+	dom_node_type type;
+	dom_exception exc;
+	dom_string *dnode_name;
+
+	/* We flip this to 1 if/when we count this node */
+	ret = 0;
+
+	if (dnode == NULL) {
+		return ret;
+	}
+
+	exc = dom_node_get_node_type(dnode, &type);
+	if ((exc != DOM_NO_ERR) || (type != DOM_ELEMENT_NODE)) {
+		/* We only count element siblings */
+		return ret;
+	}
+
+	/* ... with the right name */
+	if (check_name) {
+		dnode_name = NULL;
+		exc = dom_node_get_node_name(dnode, &dnode_name);
+
+		if ((exc == DOM_NO_ERR) && (dnode_name != NULL)) {
+			if (dom_string_isequal(name,
+					dnode_name)) {
+					ret = 1;
+			}
+			dom_string_unref(dnode_name);
+		}
+	}
+	else {
+		ret = 1;
+	}
+
+	return ret;
+}
+
+/**
+ * Count the given node's sibling elements
+ *
+ * This counts the given node's sibling elements in one direction,
+ * either forwards or backwards, in the DOM. Keep in mind that the
+ * libdom tree is upside-down compared to the CSS one; so "next" and
+ * "previous" are actually reversed; the default is to count preceding
+ * libdom siblings which correspond to subsequent CSS siblings.
+ *
+ * This operation is central to the CSS :first-child, :nth-child, and
+ * :last-child (et cetera) pseudo-selectors.
+ *
+ * If same_name is true, then only nodes having the same
+ * (case-sensitive) name as the given node are counted.
+ *
+ * \param pw          Pointer to the current SVG parser state
+ * \param node        Libdom SVG node whose siblings we're counting
+ * \param same_name   Whether or not to count only siblings having
+ *                    the same name as the given node
+ * \param after       Count subsequent siblings rather than precedent
+ *                    ones (the default)
+ * \param count       Pointer to the return value, the number of sibling
+ *                    elements
+ *
+ * \return CSS_OK on success, or CSS_NOMEM if anything goes wrong
+ */
+css_error node_count_siblings(void *pw, void *node,
+		bool same_name, bool after, int32_t *count)
+{
+	UNUSED(pw);
+	dom_exception exc;
+	dom_node *dnode; /* node, but with the right type */
+	dom_string *dnode_name;
+	dom_node *next; /* "next" sibling (depends on direction) */
+
+	/* Pointer to the "next sibling" function */
+	dom_exception (*next_func)(dom_node *, dom_node **);
+
+	*count = 0;
+
+	dnode_name = NULL;
+	dnode = (dom_node *)node;
+	if (same_name) {
+		exc = dom_node_get_node_name(dnode, &dnode_name);
+		if ((exc != DOM_NO_ERR) || (dnode_name == NULL)) {
+			return CSS_NOMEM;
+		}
+	}
+
+	/* Increment the reference counter for dnode for as long as
+	 * we retain a reference to it. */
+	dnode = dom_node_ref(dnode);
+
+	next_func = dom_node_get_previous_sibling;
+	if (after) {
+		next_func = dom_node_get_next_sibling;
+	}
+
+	do {
+		exc = next_func(dnode, &next);
+		if (exc != DOM_NO_ERR) {
+			break;
+		}
+
+		/* If next_func worked, we're about to swap "next"
+		 * with "dnode" meaning that we will no longer retain
+		 * a reference to the current dnode. */
+		dom_node_unref(dnode);
+		dnode = next;
+
+		*count += node_count_siblings_check(dnode,
+					same_name,
+					dnode_name);
+	} while (dnode != NULL);
+
+	if (dnode_name != NULL) {
+		dom_string_unref(dnode_name);
+	}
+
+	return CSS_OK;
+}
+
+
+/**
+ * Determine whether or not the given element is empty
+ *
+ * An element is "nonempty" if it has a child that is either an
+ * element node or a text node.
+ *
+ * \param pw          Pointer to the current SVG parser state
+ * \param node        Libdom SVG node to check for emptiness
+ * \param is_empty    Pointer to the return value
+ *
+ * \return CSS_OK on success, or CSS_NOMEM if anything goes wrong
+ */
+css_error node_is_empty(void *pw, void *node, bool *is_empty)
+{
+	UNUSED(pw);
+	dom_node *child; /* current child node pointer */
+	dom_node *next;  /* next child node pointer */
+	dom_node_type type; /* what type of node is "child" */
+	dom_exception err;
+
+	/* Assume that it's empty by default */
+	*is_empty = true;
+
+	/* Get the given node's first child. Implementation detail:
+	 * this increments the reference counter on the child node. */
+	err = dom_node_get_first_child((dom_node *)node, &child);
+	if (err != DOM_NO_ERR) {
+		return CSS_NOMEM;
+	}
+
+	/* And now loop through all children looking for a
+	 * text/element node. If we find one, the original
+	 * node is "nonempty" */
+	while (child != NULL) {
+		err = dom_node_get_node_type(child, &type);
+		if (err != DOM_NO_ERR) {
+			dom_node_unref(child);
+			return CSS_NOMEM;
+		}
+
+		if (type == DOM_ELEMENT_NODE || type == DOM_TEXT_NODE) {
+			*is_empty = false;
+			dom_node_unref(child);
+			return CSS_OK;
+		}
+
+		err = dom_node_get_next_sibling(child, &next);
+		if (err != DOM_NO_ERR) {
+			dom_node_unref(child);
+			return CSS_NOMEM;
+		}
+
+		/* If we're moving to the next node, we can release
+		 * the reference to the current one */
+		dom_node_unref(child);
+		child = next;
+	}
+
+	return CSS_OK;
+}
+
+
+/**
+ * Determine whether or not the given node is a link
+ *
+ * A node is a link if it is an element node whose name is "a" and if
+ * it has an "href" attribute (case-sensitive). This selector
+ * corresponds to node:link pseudo-class in CSS.
+ *
+ * This pseudo-class is a bit awkward because the two standards (HTML5
+ * and CSS) disagree on what it means, and because libsvgtiny does not
+ * have enough information to determine if a link has been "visited"
+ * yet -- that's a UI property. CSS says that :link is for unvisited
+ * links, which we can't determine. HTML5 says that each link must
+ * be either a :link or :visited. Since we can't decide either way,
+ * It seems less wrong to declare that all links are unvisited; i.e.
+ * that they match :link.
+ *
+ * \param pw          Pointer to the current SVG parser state
+ * \param node        Libdom SVG node to check
+ * \param is_link     Pointer to the boolean return value
+ *
+ * \return CSS_OK on success, or CSS_NOMEM if anything goes wrong
+ */
+css_error node_is_link(void *pw, void *node, bool *is_link)
+{
+	dom_exception exc;
+	dom_node *dnode; /* node, but with the right type */
+	dom_string *dnode_name;
+	bool has_href;
+	struct svgtiny_parse_state* state;
+
+	dnode = (dom_node *)node;
+	dnode_name = NULL;
+	has_href = false; /* assume no href attribute */
+	*is_link = false; /* assume that it's not a link */
+
+	exc = dom_node_get_node_name(dnode, &dnode_name);
+	if ((exc != DOM_NO_ERR) || (dnode_name == NULL)) {
+		return CSS_NOMEM;
+	}
+
+	state = (struct svgtiny_parse_state *)pw;
+	if (dom_string_isequal(dnode_name, state->interned_a)) {
+		exc = dom_element_has_attribute(node,
+					state->interned_href,
+					&has_href);
+		if (exc == DOM_NO_ERR && has_href) {
+			*is_link = true;
+		}
+	}
+
+	dom_string_unref(dnode_name);
+	return CSS_OK;
+}