X-Git-Url: https://gitweb.michael.orlitzky.com/?a=blobdiff_plain;f=src%2Fsvgtiny_css.c;h=246309867a691f87b51e9143f17652c2350848f0;hb=4b509c8176d14bed97304aa2bf268bc759cfe09f;hp=8abaa03de863e308de1c09e3ea0d60ba3682326e;hpb=8a193eb5807addc9e89b5804360d1cdc72cb1889;p=libsvgtiny.git diff --git a/src/svgtiny_css.c b/src/svgtiny_css.c index 8abaa03..2463098 100644 --- a/src/svgtiny_css.c +++ b/src/svgtiny_css.c @@ -1,4 +1,5 @@ #include +#include /* strncasecmp */ #include "svgtiny.h" #include "svgtiny_internal.h" @@ -7,6 +8,37 @@ static css_error node_name(void *pw, void *node, css_qname *qname); static css_error node_classes(void *pw, void *node, lwc_string ***classes, uint32_t *n_classes); static css_error node_id(void *pw, void *node, lwc_string **id); +static css_error named_parent_node(void *pw, void *node, + const css_qname *qname, void **parent); +static css_error named_sibling_node(void *pw, void *node, + const css_qname *qname, void **sibling); +static css_error named_generic_sibling_node(void *pw, void *node, + const css_qname *qname, void **sibling); +static css_error parent_node(void *pw, void *node, void **parent); +static css_error sibling_node(void *pw, void *node, void **sibling); +static css_error node_has_name(void *pw, void *node, + const css_qname *qname, bool *match); +static css_error node_has_class(void *pw, void *node, + lwc_string *name, bool *match); +static css_error node_has_id(void *pw, void *node, + lwc_string *name, bool *match); +static css_error node_has_attribute(void *pw, void *node, + const css_qname *qname, bool *match); +static css_error node_has_attribute_equal(void *pw, void *node, + const css_qname *qname, lwc_string *value, + bool *match); +static css_error node_has_attribute_dashmatch(void *pw, void *node, + const css_qname *qname, lwc_string *value, + bool *match); +static css_error node_has_attribute_includes(void *pw, void *node, + const css_qname *qname, lwc_string *word, + bool *match); +static css_error node_has_attribute_prefix(void *pw, void *node, + const css_qname *qname, lwc_string *prefix, + bool *match); +static css_error node_has_attribute_suffix(void *pw, void *node, + const css_qname *qname, lwc_string *suffix, + bool *match); /** @@ -180,3 +212,884 @@ css_error node_id(void *pw, void *node, lwc_string **id) dom_string_unref(attr); return CSS_OK; } + + + +/** + * Find the first parent of the given element having the given name + * + * \param pw Pointer to the current SVG parser state + * \param node Libdom SVG node + * \param qname Name of the parent node to search for + * \param parent Address at which to store the parent node pointer + * + * \return Always returns CSS_OK + * + * \post If a suitable element is found, a pointer to it will be + * stored at the address pointed to by \a parent; otherwise, + * NULL will be stored at the address pointed to by \a parent + */ +css_error named_parent_node(void *pw, void *node, + const css_qname *qname, void **parent) +{ + UNUSED(pw); + /* dom_element_named_parent_node() was invented to implement + * this select handler so there isn't much for us to do except + * call it. It's OK if node isn't an element, libdom checks + * for it. */ + dom_element_named_parent_node((dom_element *)node, + qname->name, + (struct dom_element **)parent); + + /* Implementation detail: dom_element_named_parent_node() + * increments the reference count of the parent element before + * returning it to us. According to docs/RefCnt in the libdom + * repository, this will prevent the parent element from being + * destroyed if it is pruned from the DOM. That sounds good, + * since we don't want to be using a pointer to an object that + * has been destroyed... but we also have no way of later + * decrementing the reference count ourselves, and don't want + * to make the returned node eternal. Decrementing the + * reference counter now allows it to be destroyed when the + * DOM no longer needs it, and so long as no other parts of + * libsvgtiny are messing with the DOM during parsing, that + * shouldn't (ha ha) cause any problems. */ + dom_node_unref(*parent); + + return CSS_OK; +} + + +/** + * Find the "next-sibling" of the given element having the given name + * + * This search corresponds to the "+ foo" combinator in CSS and will + * find only "foo" element nodes that immediately precede the given + * node under the same parent in the DOM. In CSS the tree is viewed + * top-down and in libdom it is viewed from the bottom-up; as a result + * "next" and "previous" are sometimes backwards. This is case-sensitive. + * + * \param pw Pointer to the current SVG parser state + * \param node Libdom SVG node + * \param qname Name of the sibling node to search for + * \param sibling Address at which to store the sibling node pointer + * + * \return Always returns CSS_OK + * + * \post If a suitable element is found, a pointer to it will be + * stored at the address pointed to by \a sibling; otherwise, + * NULL will be stored at the address pointed to by \a sibling + */ +css_error named_sibling_node(void *pw, void *node, + const css_qname *qname, void **sibling) +{ + UNUSED(pw); + dom_node *n = node; /* the current node */ + dom_node *prev; /* the previous node */ + dom_exception err; + dom_node_type type; + dom_string *name; + + *sibling = NULL; /* default to nothing found */ + + /* Begin the search; the first iteration we do outside of the + * loop. Implementation detil: dom_node_get_previous_sibling() + * increments the reference counter on the returned node. A + * comment within named_parent_node() explains why we + * decrement it ASAP. */ + err = dom_node_get_previous_sibling(n, &n); + if (err != DOM_NO_ERR) { + return CSS_OK; + } + + while (n != NULL) { + /* We're looking for the first ELEMENT sibling */ + err = dom_node_get_node_type(n, &type); + if (err != DOM_NO_ERR) { + dom_node_unref(n); + return CSS_OK; + } + + if (type == DOM_ELEMENT_NODE) { + /* We found an element node, does it have the + * right name? */ + err = dom_node_get_node_name(n, &name); + if (err != DOM_NO_ERR) { + dom_node_unref(n); + return CSS_OK; + } + + if (dom_string_lwc_isequal(name, + qname->name)) { + /* The name is right, return it */ + *sibling = n; + } + + /* There's only one next-sibling element node + * and we've already found it, so if its name + * wasn't right, we return the default value + * of NULL below */ + dom_string_unref(name); + dom_node_unref(n); + return CSS_OK; + } + + /* Not an element node, so we move on the the previous + * previous sibling */ + err = dom_node_get_previous_sibling(n, &prev); + if (err != DOM_NO_ERR) { + dom_node_unref(n); + return CSS_OK; + } + + dom_node_unref(n); + n = prev; + } + + return CSS_OK; +} + + +/** + * Find the first "subsequent-sibling" of the given element having the + * given name + * + * This search corresponds to the "~ foo" combinator in CSS and will + * find only "foo" element nodes that precede the given node (under + * the same parent) in the DOM. In CSS the tree is viewed top-down and + * in libdom it is viewed from the bottom-up; as a result "next" and + * "previous" are sometimes backwards. This is case-sensitive. + * + * \param pw Pointer to the current SVG parser state + * \param node Libdom SVG node + * \param qname Name of the sibling node to search for + * \param sibling Address at which to store the sibling node pointer + * + * \return Always returns CSS_OK + * + * \post If a suitable element is found, a pointer to it will be + * stored at the address pointed to by \a sibling; otherwise, + * NULL will be stored at the address pointed to by \a sibling + */ +css_error named_generic_sibling_node(void *pw, void *node, + const css_qname *qname, void **sibling) +{ + UNUSED(pw); + dom_node *n = node; /* the current node */ + dom_node *prev; /* the previous node */ + dom_exception err; + dom_node_type type; + dom_string *name; + + + *sibling = NULL; /* default to nothing found */ + + /* Begin the search; the first iteration we do outside of the + * loop. Implementation detil: dom_node_get_previous_sibling() + * increments the reference counter on the returned node. A + * comment within named_parent_node() explains why we + * decrement it ASAP. */ + err = dom_node_get_previous_sibling(n, &n); + if (err != DOM_NO_ERR) { + return CSS_OK; + } + + while (n != NULL) { + err = dom_node_get_node_type(n, &type); + if (err != DOM_NO_ERR) { + dom_node_unref(n); + return CSS_OK; + } + + if (type == DOM_ELEMENT_NODE) { + /* We only want ELEMENT nodes */ + err = dom_node_get_node_name(n, &name); + if (err != DOM_NO_ERR) { + dom_node_unref(n); + return CSS_OK; + } + + if (dom_string_lwc_isequal(name, + qname->name)) { + /* Found one. Save it and stop the search */ + dom_string_unref(name); + dom_node_unref(n); + *sibling = n; + return CSS_OK; + } + + dom_string_unref(name); + } + + /* This sibling wasn't an element with the desired + name, so move on to the previous sibling */ + err = dom_node_get_previous_sibling(n, &prev); + if (err != DOM_NO_ERR) { + dom_node_unref(n); + return CSS_OK; + } + + dom_node_unref(n); + n = prev; + } + + return CSS_OK; +} + + +/** + * Return a pointer to the given node's parent + * + * \param pw Pointer to the current SVG parser state + * \param node Libdom SVG node + * \param parent Address at which to store the node's parent pointer + * + * \return Always returns CSS_OK + */ +css_error parent_node(void *pw, void *node, void **parent) +{ + UNUSED(pw); + /* Libdom basically implements this for us */ + dom_element_parent_node(node, (struct dom_element **)parent); + + /* See the comment in named_parent_node() for why we decrement + * this reference counter here. */ + dom_node_unref(*parent); + + return CSS_OK; +} + + +/** + * Find the "next-sibling" of the given element + * + * This search corresponds "+ *" in CSS and will find the first + * element node that immediately precedes the given node under the + * same parent in the DOM. In CSS the tree is viewed top-down and in + * libdom it is viewed from the bottom-up; as a result "next" and + * "previous" are sometimes backwards. + * + * \param pw Pointer to the current SVG parser state + * \param node Libdom SVG node + * \param sibling Address at which to store the sibling node pointer + * + * \return Always returns CSS_OK + * + * \post If a suitable element is found, a pointer to it will be + * stored at the address pointed to by \a sibling; otherwise, + * NULL will be stored at the address pointed to by \a sibling + */ +css_error sibling_node(void *pw, void *node, void **sibling) +{ + UNUSED(pw); + dom_node *n = node; /* the current node */ + dom_node *prev; /* the previous node */ + dom_exception err; + dom_node_type type; + + *sibling = NULL; /* default to nothing found */ + + /* Begin the search; the first iteration we do outside of the + * loop. Implementation detil: dom_node_get_previous_sibling() + * increments the reference counter on the returned node. A + * comment within named_parent_node() explains why we + * decrement it ASAP. */ + err = dom_node_get_previous_sibling(n, &n); + if (err != DOM_NO_ERR) { + return CSS_OK; + } + + while (n != NULL) { + err = dom_node_get_node_type(n, &type); + if (err != DOM_NO_ERR) { + dom_node_unref(n); + return CSS_OK; + } + + if (type == DOM_ELEMENT_NODE) { + /* We found a sibling node that is also an + element and that's all we wanted. */ + *sibling = n; + dom_node_unref(n); + return CSS_OK; + } + + /* This sibling node was not an element; move on to + the previous sibling */ + err = dom_node_get_previous_sibling(n, &prev); + if (err != DOM_NO_ERR) { + dom_node_unref(n); + return CSS_OK; + } + + dom_node_unref(n); + n = prev; + } + + return CSS_OK; +} + + +/** + * Test the given node for the given name + * + * This will return true (via the "match" pointer) if the libdom node + * has the given name or if that name is the universal selector; + * otherwise it returns false. The comparison is case-sensitive. It + * corresponds to a rule like "body { ... }" in CSS. + * + * \param pw Pointer to the current SVG parser state + * \param node Libdom SVG node to test + * \param qname Name to check for + * \param match Pointer to the test result + * + * \return Always returns CSS_OK + */ +css_error node_has_name(void *pw, void *node, + const css_qname *qname, bool *match) +{ + struct svgtiny_parse_state *state; + dom_string *name; + dom_exception err; + + /* Start by checking to see if qname is the universal selector */ + state = (struct svgtiny_parse_state *)pw; + if (lwc_string_isequal(qname->name, + state->interned_universal, match) == lwc_error_ok) { + if (*match) { + /* It's the universal selector. In NetSurf, all node + * names match the universal selector, and nothing in + * the libcss documentation suggests another approach, + * so we follow NetSurf here. */ + return CSS_OK; + } + } + + err = dom_node_get_node_name((dom_node *)node, &name); + if (err != DOM_NO_ERR) { + return CSS_OK; + } + + /* Unlike with HTML, SVG element names are case-sensitive */ + *match = dom_string_lwc_isequal(name, qname->name); + dom_string_unref(name); + + return CSS_OK; +} + + +/** + * Test the given node for the given class + * + * This will return true (via the "match" pointer) if the libdom node + * has the given class. The comparison is case-sensitive. It + * corresponds to node.class in CSS. + * + * \param pw Pointer to the current SVG parser state + * \param node Libdom SVG node to test + * \param name Class name to check for + * \param match Pointer to the test result + * + * \return Always returns CSS_OK + */ +css_error node_has_class(void *pw, void *node, + lwc_string *name, bool *match) +{ + UNUSED(pw); + /* libdom implements this for us and apparently it cannot fail */ + dom_element_has_class((dom_node *)node, name, match); + return CSS_OK; +} + + +/** + * Test the given node for the given id + * + * This will return true (via the "match" pointer) if the libdom node + * has the given id. The comparison is case-sensitive. It corresponds + * to node#id in CSS. + * + * \param pw Pointer to the current SVG parser state + * \param node Libdom SVG node to test + * \param name Id to check for + * \param match Pointer to the test result + * + * \return Always returns CSS_OK + */ +css_error node_has_id(void *pw, void *node, + lwc_string *name, bool *match) +{ + dom_string *attr; + dom_exception err; + struct svgtiny_parse_state *state; + + attr = NULL; /* a priori the "id" attribute may not exist */ + *match = false; /* default to no match */ + + state = (struct svgtiny_parse_state *)pw; + err = dom_element_get_attribute((dom_node *)node, + state->interned_id, &attr); + if (err != DOM_NO_ERR || attr == NULL) { + return CSS_OK; + } + + *match = dom_string_lwc_isequal(attr, name); + dom_string_unref(attr); + + return CSS_OK; +} + + +/** + * Test the given node for the given attribute + * + * This will return true (via the "match" pointer) if the libdom node + * has an attribute with the given name. The comparison is + * case-sensitive. It corresponds to node[attr] in CSS. + * + * \param pw Pointer to the current SVG parser state + * \param node Libdom SVG node to test + * \param qname Attribute name to check for + * \param match Pointer to the test result + * + * \return Returns CSS_OK if successful and CSS_NOMEM if anything + * goes wrong + */ +css_error node_has_attribute(void *pw, void *node, + const css_qname *qname, bool *match) +{ + UNUSED(pw); + dom_string *name; + dom_exception err; + + /* intern the attribute name as a dom_string so we can + * delegate to dom_element_has_attribute() */ + err = dom_string_create_interned( + (const uint8_t *) lwc_string_data(qname->name), + lwc_string_length(qname->name), + &name); + if (err != DOM_NO_ERR) { + return CSS_NOMEM; + } + + err = dom_element_has_attribute((dom_node *)node, name, match); + if (err != DOM_NO_ERR) { + dom_string_unref(name); + return CSS_OK; + } + + dom_string_unref(name); + return CSS_OK; +} + + +/** + * Test the given node for an attribute with a specific value + * + * This will return true (via the "match" pointer) if the libdom node + * has an attribute with the given name and value. The comparison is + * case-sensitive. It corresponds to node[attr=value] in CSS. + * + * \param pw Pointer to the current SVG parser state + * \param node Libdom SVG node to test + * \param qname Attribute name to check for + * \param value Attribute value to check for + * \param match Pointer to the test result + * + * \return Returns CSS_OK if successful and CSS_NOMEM if we cannot + * intern the attribute name (which usually indicates memory + * exhaustion) + */ +css_error node_has_attribute_equal(void *pw, void *node, + const css_qname *qname, lwc_string *value, + bool *match) +{ + /* Implementation note: NetSurf always returns "no match" when + * the value is empty (length zero). We allow it, because why + * not? */ + + UNUSED(pw); + dom_string *name; + dom_string *attr_val; + dom_exception err; + + /* Intern the attribute name as a dom_string so we can + * use dom_element_get_attribute() */ + err = dom_string_create_interned( + (const uint8_t *) lwc_string_data(qname->name), + lwc_string_length(qname->name), + &name); + if (err != DOM_NO_ERR) { + return CSS_NOMEM; + } + + err = dom_element_get_attribute((dom_node *)node, name, &attr_val); + if ((err != DOM_NO_ERR) || (attr_val == NULL)) { + /* There was an error getting the attribute's value or + * the attribute doesn't exist. So, no match? */ + dom_string_unref(name); + *match = false; + return CSS_OK; + } + + /* Otherwise, we have the attribute value from the given node + * and all we need to do is compare. */ + dom_string_unref(name); + *match = dom_string_lwc_isequal(attr_val, value); + dom_string_unref(attr_val); + + return CSS_OK; +} + + +/** + * Test the given node for an attribute with a specific value, + * possibly followed by a single hyphen + * + * This will return true (via the "match" pointer) if the libdom node + * has an attribute with the given name and value or with the given + * name and a value that is followed by exactly one hyphen. The + * comparison is case-sensitive. This corresponds to [attr|=value] + * in CSS. + * + * \param pw Pointer to the current SVG parser state + * \param node Libdom SVG node to test + * \param qname Attribute name to check for + * \param value Attribute value to check for + * \param match Pointer to the test result + * + * \return Returns CSS_OK if successful and CSS_NOMEM if we cannot + * intern the attribute name (which usually indicates memory + * exhaustion) + */ +css_error node_has_attribute_dashmatch(void *pw, void *node, + const css_qname *qname, lwc_string *value, + bool *match) +{ + /* Implementation note: NetSurf always returns "no match" when + * the value is empty (length zero). We allow it, because why + * not? */ + + UNUSED(pw); + dom_string *name; + dom_string *attr_val; + dom_exception err; + + const char *vdata; /* to hold the data underlying "value" */ + size_t vdata_len; + const char *avdata; /* to hold the found attribute value data */ + size_t avdata_len; + + /* Intern the attribute name as a dom_string so we can + * use dom_element_get_attribute() */ + err = dom_string_create_interned( + (const uint8_t *) lwc_string_data(qname->name), + lwc_string_length(qname->name), + &name); + if (err != DOM_NO_ERR) { + return CSS_NOMEM; + } + + err = dom_element_get_attribute((dom_node *)node, name, &attr_val); + if ((err != DOM_NO_ERR) || (attr_val == NULL)) { + /* There was an error getting the attribute's value or + * the attribute doesn't exist. So, no match? */ + dom_string_unref(name); + *match = false; + return CSS_OK; + } + + /* Otherwise, we have the attribute value from the given node + * and all we need to do is compare. */ + dom_string_unref(name); + *match = dom_string_lwc_isequal(attr_val, value); + if (*match) { + /* Exact match, we're done */ + dom_string_unref(attr_val); + return CSS_OK; + } + + /* No exact match, try it with a hyphen on the end */ + vdata = lwc_string_data(value); /* needle */ + vdata_len = lwc_string_length(value); + avdata = dom_string_data(attr_val); /* haystack */ + avdata_len = dom_string_byte_length(attr_val); + dom_string_unref(attr_val); + + if (avdata_len > vdata_len && avdata[vdata_len] == '-') { + if (strncasecmp(avdata, vdata, vdata_len) == 0) { + /* If there's a hyphen in the right position, + * it suffices to compare the strings only up + * to the hyphen */ + *match = true; + } + } + + return CSS_OK; +} + + +/** + * Test the given node for an attribute whose value is a + * space-separated list of words, one of which is the given word + * + * This will return true (via the "match" pointer) if the libdom node + * has an attribute with the given name and whose value when + * considered as a space-separated list of words contains the given + * word. The comparison is case-sensitive. This corresponds to + * [attr~=value] in CSS. + * + * \param pw Pointer to the current SVG parser state + * \param node Libdom SVG node to test + * \param qname Attribute name to check for + * \param word Value word to check for + * \param match Pointer to the test result + * + * \return Returns CSS_OK if successful and CSS_NOMEM if we cannot + * intern the attribute name (which usually indicates memory + * exhaustion) + */ +css_error node_has_attribute_includes(void *pw, void *node, + const css_qname *qname, lwc_string *word, + bool *match) +{ + UNUSED(pw); + + dom_string *name; + dom_string *attr_val; + dom_exception err; + size_t wordlen; /* length of "word" */ + + /* pointers used to parse a space-separated list of words */ + const char *p; + const char *start; + const char *end; + + *match = false; /* default to no match */ + + wordlen = lwc_string_length(word); + if (wordlen == 0) { + /* In this case, the spec says that "if 'val' is the + * empty string, it will never represent anything." */ + return CSS_OK; + } + + /* Intern the attribute name as a dom_string so we can + * use dom_element_get_attribute() */ + err = dom_string_create_interned( + (const uint8_t *) lwc_string_data(qname->name), + lwc_string_length(qname->name), + &name); + if (err != DOM_NO_ERR) { + return CSS_NOMEM; + } + + err = dom_element_get_attribute((dom_node *)node, name, &attr_val); + if ((err != DOM_NO_ERR) || (attr_val == NULL)) { + /* There was an error getting the attribute's value or + * the attribute doesn't exist. So, no match? */ + dom_string_unref(name); + return CSS_OK; + } + + /* Parse the list comparing each word against "word" */ + start = dom_string_data(attr_val); + end = start + dom_string_byte_length(attr_val); + dom_string_unref(attr_val); + + for (p = start; p <= end; p++) { + /* Move forward until we find the end of the first word */ + if (*p == ' ' || *p == '\0') { + /* If the length of that word is the length of the + * word we're looking for, do the comparison. */ + if ((size_t) (p - start) == wordlen && + strncasecmp(start, + lwc_string_data(word), + wordlen) == 0) { + *match = true; + break; + } + /* No match? Set "start" to the beginning of + * the next word and loop. */ + start = p + 1; + } + } + + return CSS_OK; +} + + +/** + * Test the given node for an attribute whose value begins with the + * given prefix + * + * This will return true (via the "match" pointer) if the libdom node + * has an attribute with the given name and whose value begins with + * the given prefix string. The comparison is case-sensitive. This + * corresponds to [attr^=value] in CSS. + * + * \param pw Pointer to the current SVG parser state + * \param node Libdom SVG node to test + * \param qname Attribute name to check for + * \param prefix Value prefix to check for + * \param match Pointer to the test result + * + * \return Returns CSS_OK if successful and CSS_NOMEM if we cannot + * intern the attribute name (which usually indicates memory + * exhaustion) + */ +css_error node_has_attribute_prefix(void *pw, void *node, + const css_qname *qname, lwc_string *prefix, + bool *match) +{ + UNUSED(pw); + dom_string *name; + dom_string *attr_val; + dom_exception err; + const char *avdata; /* attribute value data */ + size_t avdata_len; /* length of that attribute value data */ + size_t prefixlen; /* length of "prefix" */ + + prefixlen = lwc_string_length(prefix); + if (prefixlen == 0) { + /* In this case, the spec says that "if 'val' is the + * empty string, it will never represent anything." */ + return CSS_OK; + } + + /* Intern the attribute name as a dom_string so we can + * use dom_element_get_attribute() */ + err = dom_string_create_interned( + (const uint8_t *) lwc_string_data(qname->name), + lwc_string_length(qname->name), + &name); + if (err != DOM_NO_ERR) { + return CSS_NOMEM; + } + + err = dom_element_get_attribute((dom_node *)node, name, &attr_val); + if ((err != DOM_NO_ERR) || (attr_val == NULL)) { + /* There was an error getting the attribute's value or + * the attribute doesn't exist. So, no match? */ + dom_string_unref(name); + *match = false; + return CSS_OK; + } + + /* Otherwise, we have the attribute value from the given node, + * and the first thing we want to do is check to see if the + * whole thing matches the prefix. */ + dom_string_unref(name); + *match = dom_string_lwc_isequal(attr_val, prefix); + + /* If not, check to see if an, uh, prefix matches the + * prefix */ + if (*match == false) { + avdata = dom_string_data(attr_val); + avdata_len = dom_string_byte_length(attr_val); + if ((avdata_len >= prefixlen) && + (strncasecmp(avdata, + lwc_string_data(prefix), + prefixlen) == 0)) { + /* Use strncasecmp to compare only the first + * "n" characters, where "n" is the length of + * the prefix. */ + *match = true; + } + } + + dom_string_unref(attr_val); + + return CSS_OK; +} + + +/** + * Test the given node for an attribute whose value end with the + * given suffix + * + * This will return true (via the "match" pointer) if the libdom node + * has an attribute with the given name and whose value ends with + * the given suffix string. The comparison is case-sensitive. This + * corresponds to [attr$=value] in CSS. + * + * \param pw Pointer to the current SVG parser state + * \param node Libdom SVG node to test + * \param qname Attribute name to check for + * \param suffix Value suffix to check for + * \param match Pointer to the test result + * + * \return Returns CSS_OK if successful and CSS_NOMEM if we cannot + * intern the attribute name (which usually indicates memory + * exhaustion) + */ +css_error node_has_attribute_suffix(void *pw, void *node, + const css_qname *qname, lwc_string *suffix, + bool *match) +{ + UNUSED(pw); + dom_string *name; + dom_string *attr_val; + dom_exception err; + const char *avdata; /* attribute value data */ + size_t avdata_len; /* length of that attribute value data */ + size_t suffixlen; /* length of "suffix" */ + + /* convenience pointer we'll use when matching the suffix */ + const char *suffix_start; + + suffixlen = lwc_string_length(suffix); + if (suffixlen == 0) { + /* In this case, the spec says that "if 'val' is the + * empty string, it will never represent anything." */ + return CSS_OK; + } + + /* Intern the attribute name as a dom_string so we can + * use dom_element_get_attribute() */ + err = dom_string_create_interned( + (const uint8_t *) lwc_string_data(qname->name), + lwc_string_length(qname->name), + &name); + if (err != DOM_NO_ERR) { + return CSS_NOMEM; + } + + err = dom_element_get_attribute((dom_node *)node, name, &attr_val); + if ((err != DOM_NO_ERR) || (attr_val == NULL)) { + /* There was an error getting the attribute's value or + * the attribute doesn't exist. So, no match? */ + dom_string_unref(name); + *match = false; + return CSS_OK; + } + + /* Otherwise, we have the attribute value from the given node, + * and the first thing we want to do is check to see if the + * whole thing matches the suffix. */ + dom_string_unref(name); + *match = dom_string_lwc_isequal(attr_val, suffix); + + /* If not, check to see if an, uh, suffix matches the + * suffix */ + if (*match == false) { + avdata = dom_string_data(attr_val); + avdata_len = dom_string_byte_length(attr_val); + + suffix_start = (char *)(avdata + avdata_len - suffixlen); + + if ((avdata_len >= suffixlen) && + (strncasecmp(suffix_start, + lwc_string_data(suffix), + suffixlen) == 0)) { + /* Use strncasecmp to compare only the last + * "n" characters, where "n" is the length of + * the suffix. */ + *match = true; + } + } + + dom_string_unref(attr_val); + + return CSS_OK; +}