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libphutil/src/markup/engine/remarkup/blockrule/PhutilRemarkupListBlockRule.php
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PhutilRemarkupListBlockRule.php
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<?php
final class PhutilRemarkupListBlockRule extends PhutilRemarkupBlockRule {
/**
* This rule must apply before the Code block rule because it needs to
* win blocks which begin ` - Lorem ipsum`.
*/
public function getPriority() {
return 400;
}
public function getMatchingLineCount(array $lines, $cursor) {
$num_lines = 0;
$first_line = $cursor;
$is_one_line = false;
while (isset($lines[$cursor])) {
if (!$num_lines) {
if (preg_match(self::START_BLOCK_PATTERN, $lines[$cursor])) {
$num_lines++;
$cursor++;
$is_one_line = true;
continue;
}
} else {
if (preg_match(self::CONT_BLOCK_PATTERN, $lines[$cursor])) {
$num_lines++;
$cursor++;
$is_one_line = false;
continue;
}
// Allow lists to continue across multiple paragraphs, as long as lines
// are indented or a single empty line separates indented lines.
$this_empty = !strlen(trim($lines[$cursor]));
$this_indented = preg_match('/^ /', $lines[$cursor]);
$next_empty = true;
$next_indented = false;
if (isset($lines[$cursor + 1])) {
$next_empty = !strlen(trim($lines[$cursor + 1]));
$next_indented = preg_match('/^ /', $lines[$cursor + 1]);
}
if ($this_empty || $this_indented) {
if (($this_indented && !$this_empty) ||
($next_indented && !$next_empty)) {
$num_lines++;
$cursor++;
continue;
}
}
if ($this_empty) {
$num_lines++;
}
}
break;
}
// If this list only has one item in it, and the list marker is "#", and
// it's not the last line in the input, parse it as a header instead of a
// list. This produces better behavior for alternate Markdown headers.
if ($is_one_line) {
if (($first_line + $num_lines) < count($lines)) {
if (strncmp($lines[$first_line], '#', 1) === 0) {
return 0;
}
}
}
return $num_lines;
}
/**
* The maximum sub-list depth you can nest to. Avoids silliness and blowing
* the stack.
*/
const MAXIMUM_LIST_NESTING_DEPTH = 12;
const START_BLOCK_PATTERN = '@^\s*(?:[-*#]+|1[.)]|\[.?\])\s+@';
const CONT_BLOCK_PATTERN = '@^\s*(?:[-*#]+|[0-9]+[.)]|\[.?\])\s+@';
const STRIP_BLOCK_PATTERN = '@^\s*(?:[-*#]+|[0-9]+[.)])\s*@';
public function markupText($text, $children) {
$items = array();
$lines = explode("\n", $text);
// We allow users to delimit lists using either differing indentation
// levels:
//
// - a
// - b
//
// ...or differing numbers of item-delimiter characters:
//
// - a
// -- b
//
// If they use the second style but block-indent the whole list, we'll
// get the depth counts wrong for the first item. To prevent this,
// un-indent every item by the minimum indentation level for the whole
// block before we begin parsing.
$regex = self::START_BLOCK_PATTERN;
$min_space = PHP_INT_MAX;
foreach ($lines as $ii => $line) {
$matches = null;
if (preg_match($regex, $line)) {
$regex = self::CONT_BLOCK_PATTERN;
if (preg_match('/^(\s+)/', $line, $matches)) {
$space = strlen($matches[1]);
} else {
$space = 0;
}
$min_space = min($min_space, $space);
}
}
$regex = self::START_BLOCK_PATTERN;
if ($min_space) {
foreach ($lines as $key => $line) {
if (preg_match($regex, $line)) {
$regex = self::CONT_BLOCK_PATTERN;
$lines[$key] = substr($line, $min_space);
}
}
}
// The input text may have linewraps in it, like this:
//
// - derp derp derp derp
// derp derp derp derp
// - blarp blarp blarp blarp
//
// Group text lines together into list items, stored in $items. So the
// result in the above case will be:
//
// array(
// array(
// "- derp derp derp derp",
// " derp derp derp derp",
// ),
// array(
// "- blarp blarp blarp blarp",
// ),
// );
$item = array();
$regex = self::START_BLOCK_PATTERN;
foreach ($lines as $line) {
if (preg_match($regex, $line)) {
$regex = self::CONT_BLOCK_PATTERN;
if ($item) {
$items[] = $item;
$item = array();
}
}
$item[] = $line;
}
if ($item) {
$items[] = $item;
}
// Process each item to normalize the text, remove line wrapping, and
// determine its depth (indentation level) and style (ordered vs unordered).
//
// We preserve consecutive linebreaks and interpret them as paragraph
// breaks.
//
// Given the above example, the processed array will look like:
//
// array(
// array(
// 'text' => 'derp derp derp derp derp derp derp derp',
// 'depth' => 0,
// 'style' => '-',
// ),
// array(
// 'text' => 'blarp blarp blarp blarp',
// 'depth' => 0,
// 'style' => '-',
// ),
// );
$has_marks = false;
foreach ($items as $key => $item) {
// Trim space around newlines, to strip trailing whitespace and formatting
// indentation.
$item = preg_replace('/ *(\n+) */', '\1', implode("\n", $item));
// Replace single newlines with a space. Preserve multiple newlines as
// paragraph breaks.
$item = preg_replace('/(?<!\n)\n(?!\n)/', ' ', $item);
$item = rtrim($item);
if (!strlen($item)) {
unset($items[$key]);
continue;
}
$matches = null;
if (preg_match('/^\s*([-*#]{2,})/', $item, $matches)) {
// Alternate-style indents; use number of list item symbols.
$depth = strlen($matches[1]) - 1;
} else if (preg_match('/^(\s+)/', $item, $matches)) {
// Markdown-style indents; use indent depth.
$depth = strlen($matches[1]);
} else {
$depth = 0;
}
if (preg_match('/^\s*(?:#|[0-9])/', $item)) {
$style = '#';
} else {
$style = '-';
}
// Strip leading indicators off the item.
$text = preg_replace(self::STRIP_BLOCK_PATTERN, '', $item);
// Look for "[]", "[ ]", "[*]", "[x]", etc., which we render as a
// checkbox.
$mark = null;
$matches = null;
if (preg_match('/^\s*\[(.?)\]\s*/', $text, $matches)) {
if (strlen(trim($matches[1]))) {
$mark = true;
} else {
$mark = false;
}
$has_marks = true;
$text = substr($text, strlen($matches[0]));
}
$items[$key] = array(
'text' => $text,
'depth' => $depth,
'style' => $style,
'mark' => $mark,
);
}
$items = array_values($items);
// Users can create a sub-list by indenting any deeper amount than the
// previous list, so these are both valid:
//
// - a
// - b
//
// - a
// - b
//
// In the former case, we'll have depths (0, 2). In the latter case, depths
// (0, 4). We don't actually care about how many spaces there are, only
// how many list indentation levels (that is, we want to map both of
// those cases to (0, 1), indicating "outermost list" and "first sublist").
//
// This is made more complicated because lists at two different indentation
// levels might be at the same list level:
//
// - a
// - b
// - c
// - d
//
// Here, 'b' and 'd' are at the same list level (2) but different indent
// levels (2, 4).
//
// Users can also create "staircases" like this:
//
// - a
// - b
// # c
//
// While this is silly, we'd like to render it as faithfully as possible.
//
// In order to do this, we convert the list of nodes into a tree,
// normalizing indentation levels and inserting dummy nodes as necessary to
// make the tree well-formed. See additional notes at buildTree().
//
// In the case above, the result is a tree like this:
//
// - <null>
// - <null>
// - a
// - b
// # c
$l = 0;
$r = count($items);
$tree = $this->buildTree($items, $l, $r, $cur_level = 0);
// We may need to open a list on a <null> node, but they do not have
// list style information yet. We need to propagate list style information
// backward through the tree. In the above example, the tree now looks
// like this:
//
// - <null (style=#)>
// - <null (style=-)>
// - a
// - b
// # c
$this->adjustTreeStyleInformation($tree);
// Finally, we have enough information to render the tree.
$out = $this->renderTree($tree, 0, $has_marks);
if ($this->getEngine()->isTextMode()) {
$out = implode('', $out);
$out = rtrim($out, "\n");
$out = preg_replace('/ +$/m', '', $out);
return $out;
}
return phutil_implode_html('', $out);
}
/**
* See additional notes in @{method:markupText}.
*/
private function buildTree(array $items, $l, $r, $cur_level) {
if ($l == $r) {
return array();
}
if ($cur_level > self::MAXIMUM_LIST_NESTING_DEPTH) {
// This algorithm is recursive and we don't need you blowing the stack
// with your oh-so-clever 50,000-item-deep list. Cap indentation levels
// at a reasonable number and just shove everything deeper up to this
// level.
$nodes = array();
for ($ii = $l; $ii < $r; $ii++) {
$nodes[] = array(
'level' => $cur_level,
'items' => array(),
) + $items[$ii];
}
return $nodes;
}
$min = $l;
for ($ii = $r - 1; $ii >= $l; $ii--) {
if ($items[$ii]['depth'] <= $items[$min]['depth']) {
$min = $ii;
}
}
$min_depth = $items[$min]['depth'];
$nodes = array();
if ($min != $l) {
$nodes[] = array(
'text' => null,
'level' => $cur_level,
'style' => null,
'mark' => null,
'items' => $this->buildTree($items, $l, $min, $cur_level + 1),
);
}
$last = $min;
for ($ii = $last + 1; $ii < $r; $ii++) {
if ($items[$ii]['depth'] == $min_depth) {
$nodes[] = array(
'level' => $cur_level,
'items' => $this->buildTree($items, $last + 1, $ii, $cur_level + 1),
) + $items[$last];
$last = $ii;
}
}
$nodes[] = array(
'level' => $cur_level,
'items' => $this->buildTree($items, $last + 1, $r, $cur_level + 1),
) + $items[$last];
return $nodes;
}
/**
* See additional notes in @{method:markupText}.
*/
private function adjustTreeStyleInformation(array &$tree) {
// The effect here is just to walk backward through the nodes at this level
// and apply the first style in the list to any empty nodes we inserted
// before it. As we go, also recurse down the tree.
$style = '-';
for ($ii = count($tree) - 1; $ii >= 0; $ii--) {
if ($tree[$ii]['style'] !== null) {
// This is the earliest node we've seen with style, so set the
// style to its style.
$style = $tree[$ii]['style'];
} else {
// This node has no style, so apply the current style.
$tree[$ii]['style'] = $style;
}
if ($tree[$ii]['items']) {
$this->adjustTreeStyleInformation($tree[$ii]['items']);
}
}
}
/**
* See additional notes in @{method:markupText}.
*/
private function renderTree(array $tree, $level, $has_marks) {
$style = idx(head($tree), 'style');
$out = array();
if (!$this->getEngine()->isTextMode()) {
switch ($style) {
case '#':
$tag = 'ol';
break;
case '-':
$tag = 'ul';
break;
}
if ($has_marks) {
$out[] = hsprintf(
'<%s class="remarkup-list remarkup-list-with-checkmarks">',
$tag);
} else {
$out[] = hsprintf(
'<%s class="remarkup-list">',
$tag);
}
$out[] = "\n";
}
$number = 1;
foreach ($tree as $item) {
if ($this->getEngine()->isTextMode()) {
if ($item['text'] === null) {
// Don't render anything.
} else {
$indent = str_repeat(' ', 2 * $level);
$out[] = $indent;
if ($item['mark'] !== null) {
if ($item['mark']) {
$out[] = '[X] ';
} else {
$out[] = '[ ] ';
}
} else {
switch ($style) {
case '#':
$out[] = $number.'. ';
$number++;
break;
case '-':
$out[] = '- ';
break;
}
}
$parts = preg_split('/\n{2,}/', $item['text']);
foreach ($parts as $key => $part) {
if ($key != 0) {
$out[] = "\n\n ".$indent;
}
$out[] = $this->applyRules($part);
}
$out[] = "\n";
}
} else {
if ($item['text'] === null) {
$out[] = hsprintf('<li class="remarkup-list-item phantom-item">');
} else {
if ($item['mark'] !== null) {
if ($item['mark'] == true) {
$out[] = hsprintf(
'<li class="remarkup-list-item remarkup-checked-item">');
} else {
$out[] = hsprintf(
'<li class="remarkup-list-item remarkup-unchecked-item">');
}
$out[] = phutil_tag(
'input',
array(
'type' => 'checkbox',
'checked' => ($item['mark'] ? 'checked' : null),
'disabled' => 'disabled',
));
$out[] = ' ';
} else {
$out[] = hsprintf('<li class="remarkup-list-item">');
}
$parts = preg_split('/\n{2,}/', $item['text']);
foreach ($parts as $key => $part) {
if ($key != 0) {
$out[] = array(
"\n",
phutil_tag('br'),
phutil_tag('br'),
"\n",
);
}
$out[] = $this->applyRules($part);
}
}
}
if ($item['items']) {
$subitems = $this->renderTree($item['items'], $level + 1, $has_marks);
foreach ($subitems as $i) {
$out[] = $i;
}
}
if (!$this->getEngine()->isTextMode()) {
$out[] = hsprintf("</li>\n");
}
}
if (!$this->getEngine()->isTextMode()) {
switch ($style) {
case '#':
$out[] = hsprintf('</ol>');
break;
case '-':
$out[] = hsprintf('</ul>');
break;
}
}
return $out;
}
}
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