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/*
* This file is part of LibCSS
* Licensed under the MIT License,
* http://www.opensource.org/licenses/mit-license.php
*
* Copyright 2018 Michael Drake <tlsa@netsurf-browser.org>
*/
#ifndef css_select_mq_h_
#define css_select_mq_h_
static inline bool mq_match_feature_range_length_op1(
css_mq_feature_op op,
const css_mq_value *value,
const css_media_length *client_len)
{
if (value->type != CSS_MQ_VALUE_TYPE_DIM) {
return false;
}
/* TODO: convert to same units */
if (value->data.dim.unit != client_len->unit) {
return false;
}
switch (op) {
case CSS_MQ_FEATURE_OP_BOOL:
return false;
case CSS_MQ_FEATURE_OP_LT:
return value->data.dim.len < client_len->value;
case CSS_MQ_FEATURE_OP_LTE:
return value->data.dim.len <= client_len->value;
case CSS_MQ_FEATURE_OP_EQ:
return value->data.dim.len == client_len->value;
case CSS_MQ_FEATURE_OP_GTE:
return value->data.dim.len >= client_len->value;
case CSS_MQ_FEATURE_OP_GT:
return value->data.dim.len > client_len->value;
default:
return false;
}
}
static inline bool mq_match_feature_range_length_op2(
css_mq_feature_op op,
const css_mq_value *value,
const css_media_length *client_len)
{
if (op == CSS_MQ_FEATURE_OP_UNUSED) {
return true;
}
if (value->type != CSS_MQ_VALUE_TYPE_DIM) {
return false;
}
/* TODO: convert to same units */
if (value->data.dim.unit != client_len->unit) {
return false;
}
switch (op) {
case CSS_MQ_FEATURE_OP_LT:
return client_len->value < value->data.dim.len;
case CSS_MQ_FEATURE_OP_LTE:
return client_len->value <= value->data.dim.len;
case CSS_MQ_FEATURE_OP_EQ:
return client_len->value == value->data.dim.len;
case CSS_MQ_FEATURE_OP_GTE:
return client_len->value >= value->data.dim.len;
case CSS_MQ_FEATURE_OP_GT:
return client_len->value > value->data.dim.len;
default:
return false;
}
}
/**
* Match media query features.
*
* \param[in] feat Condition to match.
* \param[in] media Current media spec, to check against feat.
* \return true if condition matches, otherwise false.
*/
static inline bool mq_match_feature(
const css_mq_feature *feat,
const css_media *media)
{
/* TODO: Use interned string for comparison. */
if (strcmp(lwc_string_data(feat->name), "width") == 0) {
if (!mq_match_feature_range_length_op1(
feat->op, &feat->value, &media->width)) {
return false;
}
return mq_match_feature_range_length_op2(
feat->op2, &feat->value2, &media->width);
} else if (strcmp(lwc_string_data(feat->name), "height") == 0) {
if (!mq_match_feature_range_length_op1(
feat->op, &feat->value, &media->height)) {
return false;
}
return mq_match_feature_range_length_op2(
feat->op2, &feat->value2, &media->height);
}
/* TODO: Look at other feature names. */
return false;
}
/**
* Match media query conditions.
*
* \param[in] cond Condition to match.
* \param[in] media Current media spec, to check against cond.
* \return true if condition matches, otherwise false.
*/
static inline bool mq_match_condition(
const css_mq_cond *cond,
const css_media *media)
{
bool matched = !cond->op;
for (uint32_t i = 0; i < cond->parts->nparts; i++) {
bool part_matched;
if (cond->parts->parts[i]->type == CSS_MQ_FEATURE) {
part_matched = mq_match_feature(
cond->parts->parts[i]->data.feat,
media);
} else {
assert(cond->parts->parts[i]->type == CSS_MQ_COND);
part_matched = mq_match_condition(
cond->parts->parts[i]->data.cond,
media);
}
if (cond->op) {
/* OR */
matched |= part_matched;
if (matched) {
break; /* Short-circuit */
}
} else {
/* AND */
matched &= part_matched;
if (!matched) {
break; /* Short-circuit */
}
}
}
return matched != cond->negate;
}
/**
* Test whether media query list matches current media.
*
* If anything in the list matches, the list matches. If none match
* it doesn't match.
*
* \param[in] m Media query list.
* \param[in] media Current media spec, to check against m.
* \return true if media query list matches media
*/
static inline bool mq__list_match(
const css_mq_query *m,
const css_media *media)
{
for (; m != NULL; m = m->next) {
/* Check type */
if (!!(m->type & media->type) != m->negate_type) {
if (m->cond == NULL ||
mq_match_condition(m->cond, media)) {
/* We have a match, no need to look further. */
return true;
}
}
}
return false;
}
/**
* Test whether the rule applies for current media.
*
* \param rule Rule to test
* \param media Current media spec
* \return true iff chain's rule applies for media
*/
static inline bool mq_rule_good_for_media(const css_rule *rule, const css_media *media)
{
bool applies = true;
const css_rule *ancestor = rule;
while (ancestor != NULL) {
const css_rule_media *m = (const css_rule_media *) ancestor;
if (ancestor->type == CSS_RULE_MEDIA) {
applies = mq__list_match(m->media, media);
if (applies == false) {
break;
}
}
if (ancestor->ptype != CSS_RULE_PARENT_STYLESHEET) {
ancestor = ancestor->parent;
} else {
ancestor = NULL;
}
}
return applies;
}
#endif
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