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PhabricatorMarkupEngine.php
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Tue, Nov 26, 20:55

PhabricatorMarkupEngine.php
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<?php
/**
* Manages markup engine selection, configuration, application, caching and
* pipelining.
*
* @{class:PhabricatorMarkupEngine} can be used to render objects which
* implement @{interface:PhabricatorMarkupInterface} in a batched, cache-aware
* way. For example, if you have a list of comments written in remarkup (and
* the objects implement the correct interface) you can render them by first
* building an engine and adding the fields with @{method:addObject}.
*
* $field = 'field:body'; // Field you want to render. Each object exposes
* // one or more fields of markup.
*
* $engine = new PhabricatorMarkupEngine();
* foreach ($comments as $comment) {
* $engine->addObject($comment, $field);
* }
*
* Now, call @{method:process} to perform the actual cache/rendering
* step. This is a heavyweight call which does batched data access and
* transforms the markup into output.
*
* $engine->process();
*
* Finally, do something with the results:
*
* $results = array();
* foreach ($comments as $comment) {
* $results[] = $engine->getOutput($comment, $field);
* }
*
* If you have a single object to render, you can use the convenience method
* @{method:renderOneObject}.
*
* @task markup Markup Pipeline
* @task engine Engine Construction
*/
final class PhabricatorMarkupEngine {
private $objects = array();
private $viewer;
private $version = 3;
/* -( Markup Pipeline )---------------------------------------------------- */
/**
* Convenience method for pushing a single object through the markup
* pipeline.
*
* @param PhabricatorMarkupInterface The object to render.
* @param string The field to render.
* @param PhabricatorUser User viewing the markup.
* @return string Marked up output.
* @task markup
*/
public static function renderOneObject(
PhabricatorMarkupInterface $object,
$field,
PhabricatorUser $viewer) {
return id(new PhabricatorMarkupEngine())
->setViewer($viewer)
->addObject($object, $field)
->process()
->getOutput($object, $field);
}
/**
* Queue an object for markup generation when @{method:process} is
* called. You can retrieve the output later with @{method:getOutput}.
*
* @param PhabricatorMarkupInterface The object to render.
* @param string The field to render.
* @return this
* @task markup
*/
public function addObject(PhabricatorMarkupInterface $object, $field) {
$key = $this->getMarkupFieldKey($object, $field);
$this->objects[$key] = array(
'object' => $object,
'field' => $field,
);
return $this;
}
/**
* Process objects queued with @{method:addObject}. You can then retrieve
* the output with @{method:getOutput}.
*
* @return this
* @task markup
*/
public function process() {
$keys = array();
foreach ($this->objects as $key => $info) {
if (!isset($info['markup'])) {
$keys[] = $key;
}
}
if (!$keys) {
return;
}
$objects = array_select_keys($this->objects, $keys);
// Build all the markup engines. We need an engine for each field whether
// we have a cache or not, since we still need to postprocess the cache.
$engines = array();
foreach ($objects as $key => $info) {
$engines[$key] = $info['object']->newMarkupEngine($info['field']);
$engines[$key]->setConfig('viewer', $this->viewer);
}
// Load or build the preprocessor caches.
$blocks = $this->loadPreprocessorCaches($engines, $objects);
// Finalize the output.
foreach ($objects as $key => $info) {
$data = $blocks[$key]->getCacheData();
$engine = $engines[$key];
$field = $info['field'];
$object = $info['object'];
$output = $engine->postprocessText($data);
$output = $object->didMarkupText($field, $output, $engine);
$this->objects[$key]['output'] = $output;
}
return $this;
}
/**
* Get the output of markup processing for a field queued with
* @{method:addObject}. Before you can call this method, you must call
* @{method:process}.
*
* @param PhabricatorMarkupInterface The object to retrieve.
* @param string The field to retrieve.
* @return string Processed output.
* @task markup
*/
public function getOutput(PhabricatorMarkupInterface $object, $field) {
$key = $this->getMarkupFieldKey($object, $field);
if (empty($this->objects[$key])) {
throw new Exception(
"Call addObject() before getOutput() (key = '{$key}').");
}
if (!isset($this->objects[$key]['output'])) {
throw new Exception(
"Call process() before getOutput().");
}
return $this->objects[$key]['output'];
}
/**
* @task markup
*/
private function getMarkupFieldKey(
PhabricatorMarkupInterface $object,
$field) {
return $object->getMarkupFieldKey($field).'@'.$this->version;
}
/**
* @task markup
*/
private function loadPreprocessorCaches(array $engines, array $objects) {
$blocks = array();
$use_cache = array();
foreach ($objects as $key => $info) {
if ($info['object']->shouldUseMarkupCache($info['field'])) {
$use_cache[$key] = true;
}
}
if ($use_cache) {
try {
$blocks = id(new PhabricatorMarkupCache())->loadAllWhere(
'cacheKey IN (%Ls)',
array_keys($use_cache));
$blocks = mpull($blocks, null, 'getCacheKey');
} catch (Exception $ex) {
phlog($ex);
}
}
foreach ($objects as $key => $info) {
if (isset($blocks[$key])) {
// If we already have a preprocessing cache, we don't need to rebuild
// it.
continue;
}
$text = $info['object']->getMarkupText($info['field']);
$data = $engines[$key]->preprocessText($text);
// NOTE: This is just debugging information to help sort out cache issues.
// If one machine is misconfigured and poisoning caches you can use this
// field to hunt it down.
$metadata = array(
'host' => php_uname('n'),
);
$blocks[$key] = id(new PhabricatorMarkupCache())
->setCacheKey($key)
->setCacheData($data)
->setMetadata($metadata);
if (isset($use_cache[$key])) {
// This is just filling a cache and always safe, even on a read pathway.
$unguarded = AphrontWriteGuard::beginScopedUnguardedWrites();
$blocks[$key]->replace();
unset($unguarded);
}
}
return $blocks;
}
/**
* Set the viewing user. Used to implement object permissions.
*
* @param PhabricatorUser The viewing user.
* @return this
* @task markup
*/
public function setViewer(PhabricatorUser $viewer) {
$this->viewer = $viewer;
return $this;
}
/* -( Engine Construction )------------------------------------------------ */
/**
* @task engine
*/
public static function newManiphestMarkupEngine() {
return self::newMarkupEngine(array(
));
}
/**
* @task engine
*/
public static function newPhrictionMarkupEngine() {
return self::newMarkupEngine(array(
'header.generate-toc' => true,
));
}
/**
* @task engine
*/
public static function newPhameMarkupEngine() {
return self::newMarkupEngine(array(
'macros' => false,
));
}
/**
* @task engine
*/
public static function newFeedMarkupEngine() {
return self::newMarkupEngine(
array(
'macros' => false,
'youtube' => false,
));
}
/**
* @task engine
*/
public static function newDifferentialMarkupEngine(array $options = array()) {
return self::newMarkupEngine(array(
'custom-inline' => PhabricatorEnv::getEnvConfig(
'differential.custom-remarkup-rules'),
'custom-block' => PhabricatorEnv::getEnvConfig(
'differential.custom-remarkup-block-rules'),
'differential.diff' => idx($options, 'differential.diff'),
));
}
/**
* @task engine
*/
public static function newDiffusionMarkupEngine(array $options = array()) {
return self::newMarkupEngine(array(
));
}
/**
* @task engine
*/
public static function newProfileMarkupEngine() {
return self::newMarkupEngine(array(
));
}
/**
* @task engine
*/
public static function newSlowvoteMarkupEngine() {
return self::newMarkupEngine(array(
));
}
public static function newPonderMarkupEngine(array $options = array()) {
return self::newMarkupEngine($options);
}
/**
* @task engine
*/
private static function getMarkupEngineDefaultConfiguration() {
return array(
'pygments' => PhabricatorEnv::getEnvConfig('pygments.enabled'),
'youtube' => PhabricatorEnv::getEnvConfig(
'remarkup.enable-embedded-youtube'),
'custom-inline' => array(),
'custom-block' => array(),
'differential.diff' => null,
'header.generate-toc' => false,
'macros' => true,
'uri.allowed-protocols' => PhabricatorEnv::getEnvConfig(
'uri.allowed-protocols'),
'syntax-highlighter.engine' => PhabricatorEnv::getEnvConfig(
'syntax-highlighter.engine'),
);
}
/**
* @task engine
*/
public static function newMarkupEngine(array $options) {
$options += self::getMarkupEngineDefaultConfiguration();
$engine = new PhutilRemarkupEngine();
$engine->setConfig('preserve-linebreaks', true);
$engine->setConfig('pygments.enabled', $options['pygments']);
$engine->setConfig(
'uri.allowed-protocols',
$options['uri.allowed-protocols']);
$engine->setConfig('differential.diff', $options['differential.diff']);
$engine->setConfig('header.generate-toc', $options['header.generate-toc']);
$engine->setConfig(
'syntax-highlighter.engine',
$options['syntax-highlighter.engine']);
$rules = array();
$rules[] = new PhutilRemarkupRuleEscapeRemarkup();
$rules[] = new PhutilRemarkupRuleMonospace();
$custom_rule_classes = $options['custom-inline'];
if ($custom_rule_classes) {
foreach ($custom_rule_classes as $custom_rule_class) {
$rules[] = newv($custom_rule_class, array());
}
}
$rules[] = new PhutilRemarkupRuleDocumentLink();
if ($options['youtube']) {
$rules[] = new PhabricatorRemarkupRuleYoutube();
}
$rules[] = new PhutilRemarkupRuleHyperlink();
$rules[] = new PhabricatorRemarkupRulePhriction();
$rules[] = new PhabricatorRemarkupRuleDifferentialHandle();
if (PhabricatorEnv::getEnvConfig('maniphest.enabled')) {
$rules[] = new PhabricatorRemarkupRuleManiphestHandle();
}
$rules[] = new PhabricatorRemarkupRuleEmbedFile();
$rules[] = new PhabricatorRemarkupRuleDifferential();
$rules[] = new PhabricatorRemarkupRuleDiffusion();
if (PhabricatorEnv::getEnvConfig('maniphest.enabled')) {
$rules[] = new PhabricatorRemarkupRuleManiphest();
}
$rules[] = new PhabricatorRemarkupRulePaste();
$rules[] = new PhabricatorRemarkupRuleCountdown();
$rules[] = new PonderRuleQuestion();
if ($options['macros']) {
$rules[] = new PhabricatorRemarkupRuleImageMacro();
$rules[] = new PhabricatorRemarkupRuleMeme();
}
$rules[] = new PhabricatorRemarkupRuleMention();
$rules[] = new PhutilRemarkupRuleBold();
$rules[] = new PhutilRemarkupRuleItalic();
$rules[] = new PhutilRemarkupRuleDel();
$blocks = array();
$blocks[] = new PhutilRemarkupEngineRemarkupQuotesBlockRule();
$blocks[] = new PhutilRemarkupEngineRemarkupLiteralBlockRule();
$blocks[] = new PhutilRemarkupEngineRemarkupHeaderBlockRule();
$blocks[] = new PhutilRemarkupEngineRemarkupListBlockRule();
$blocks[] = new PhutilRemarkupEngineRemarkupCodeBlockRule();
$blocks[] = new PhutilRemarkupEngineRemarkupNoteBlockRule();
$blocks[] = new PhutilRemarkupEngineRemarkupTableBlockRule();
$blocks[] = new PhutilRemarkupEngineRemarkupSimpleTableBlockRule();
$blocks[] = new PhutilRemarkupEngineRemarkupDefaultBlockRule();
$custom_block_rule_classes = $options['custom-block'];
if ($custom_block_rule_classes) {
foreach ($custom_block_rule_classes as $custom_block_rule_class) {
$blocks[] = newv($custom_block_rule_class, array());
}
}
foreach ($blocks as $block) {
if ($block instanceof PhutilRemarkupEngineRemarkupLiteralBlockRule) {
$literal_rules = array();
$literal_rules[] = new PhutilRemarkupRuleLinebreaks();
$block->setMarkupRules($literal_rules);
} else if (
!($block instanceof PhutilRemarkupEngineRemarkupCodeBlockRule)) {
$block->setMarkupRules($rules);
}
}
$engine->setBlockRules($blocks);
return $engine;
}
public static function extractPHIDsFromMentions(array $content_blocks) {
$mentions = array();
$engine = self::newDifferentialMarkupEngine();
foreach ($content_blocks as $content_block) {
$engine->markupText($content_block);
$phids = $engine->getTextMetadata(
PhabricatorRemarkupRuleMention::KEY_MENTIONED,
array());
$mentions += $phids;
}
return $mentions;
}
public static function extractFilePHIDsFromEmbeddedFiles(
array $content_blocks) {
$files = array();
$engine = self::newDifferentialMarkupEngine();
foreach ($content_blocks as $content_block) {
$engine->markupText($content_block);
$ids = $engine->getTextMetadata(
PhabricatorRemarkupRuleEmbedFile::KEY_EMBED_FILE_PHIDS,
array());
$files += $ids;
}
return $files;
}
/**
* Produce a corpus summary, in a way that shortens the underlying text
* without truncating it somewhere awkward.
*
* TODO: We could do a better job of this.
*
* @param string Remarkup corpus to summarize.
* @return string Summarized corpus.
*/
public static function summarize($corpus) {
// Major goals here are:
// - Don't split in the middle of a character (utf-8).
// - Don't split in the middle of, e.g., **bold** text, since
// we end up with hanging '**' in the summary.
// - Try not to pick an image macro, header, embedded file, etc.
// - Hopefully don't return too much text. We don't explicitly limit
// this right now.
$blocks = preg_split("/\n *\n\s*/", trim($corpus));
$best = null;
foreach ($blocks as $block) {
// This is a test for normal spaces in the block, i.e. a heuristic to
// distinguish standard paragraphs from things like image macros. It may
// not work well for non-latin text. We prefer to summarize with a
// paragraph of normal words over an image macro, if possible.
$has_space = preg_match('/\w\s\w/', $block);
// This is a test to find embedded images and headers. We prefer to
// summarize with a normal paragraph over a header or an embedded object,
// if possible.
$has_embed = preg_match('/^[{=]/', $block);
if ($has_space && !$has_embed) {
// This seems like a good summary, so return it.
return $block;
}
if (!$best) {
// This is the first block we found; if everything is garbage just
// use the first block.
$best = $block;
}
}
return $best;
}
}

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