<?php
/**
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 * http://www.gnu.org/copyleft/gpl.html
 *
 * @file
 */

/**
 * Profiler wrapper for XHProf extension.
 *
 * @code
 * $wgProfiler['class'] = 'ProfilerXhprof';
 * $wgProfiler['flags'] = XHPROF_FLAGS_NO_BUILTINS;
 * $wgProfiler['output'] = 'text';
 * $wgProfiler['visible'] = true;
 * @endcode
 *
 * @code
 * $wgProfiler['class'] = 'ProfilerXhprof';
 * $wgProfiler['flags'] = XHPROF_FLAGS_CPU | XHPROF_FLAGS_MEMORY | XHPROF_FLAGS_NO_BUILTINS;
 * $wgProfiler['output'] = 'udp';
 * @endcode
 *
 * ProfilerXhprof profiles all functions using the XHProf PHP extenstion.
 * For PHP5 users, this extension can be installed via PECL or your operating
 * system's package manager. XHProf support is built into HHVM.
 *
 * To restrict the functions for which profiling data is collected, you can
 * use either a whitelist ($wgProfiler['include']) or a blacklist
 * ($wgProfiler['exclude']) containing an array of function names.
 * Shell-style patterns are also accepted.
 *
 * It is also possible to use the Tideways PHP extension, which is mostly
 * a drop-in replacement for Xhprof. Just change the XHPROF_FLAGS_* constants
 * to TIDEWAYS_FLAGS_*.
 *
 * @author Bryan Davis <bd808@wikimedia.org>
 * @copyright © 2014 Bryan Davis and Wikimedia Foundation.
 * @ingroup Profiler
 * @see Xhprof
 * @see https://php.net/xhprof
 * @see https://github.com/facebook/hhvm/blob/master/hphp/doc/profiling.md
 * @see https://github.com/tideways/php-profiler-extension
 */
class ProfilerXhprof extends Profiler {
	/**
	 * @var XhprofData|null $xhprofData
	 */
	protected $xhprofData;

	/**
	 * Profiler for explicit, arbitrary, frame labels
	 * @var SectionProfiler
	 */
	protected $sprofiler;

	/**
	 * @param array $params
	 * @see Xhprof::__construct()
	 */
	public function __construct( array $params = [] ) {
		parent::__construct( $params );

		$flags = isset( $params['flags'] ) ? $params['flags'] : 0;
		$options = isset( $params['exclude'] )
			? [ 'ignored_functions' => $params['exclude'] ] : [];
		Xhprof::enable( $flags, $options );
		$this->sprofiler = new SectionProfiler();
	}

	/**
	 * @return XhprofData
	 */
	public function getXhprofData() {
		if ( !$this->xhprofData ) {
			$this->xhprofData = new XhprofData( Xhprof::disable(), $this->params );
		}
		return $this->xhprofData;
	}

	public function scopedProfileIn( $section ) {
		$key = 'section.' . ltrim( $section, '.' );
		return $this->sprofiler->scopedProfileIn( $key );
	}

	/**
	 * No-op for xhprof profiling.
	 */
	public function close() {
	}

	/**
	 * Check if a function or section should be excluded from the output.
	 *
	 * @param string $name Function or section name.
	 * @return bool
	 */
	private function shouldExclude( $name ) {
		if ( $name === '-total' ) {
			return true;
		}
		if ( !empty( $this->params['include'] ) ) {
			foreach ( $this->params['include'] as $pattern ) {
				if ( fnmatch( $pattern, $name, FNM_NOESCAPE ) ) {
					return false;
				}
			}
			return true;
		}
		if ( !empty( $this->params['exclude'] ) ) {
			foreach ( $this->params['exclude'] as $pattern ) {
				if ( fnmatch( $pattern, $name, FNM_NOESCAPE ) ) {
					return true;
				}
			}
		}
		return false;
	}

	public function getFunctionStats() {
		$metrics = $this->getXhprofData()->getCompleteMetrics();
		$profile = [];

		$main = null; // units in ms
		foreach ( $metrics as $fname => $stats ) {
			if ( $this->shouldExclude( $fname ) ) {
				continue;
			}
			// Convert elapsed times from μs to ms to match interface
			$entry = [
				'name' => $fname,
				'calls' => $stats['ct'],
				'real' => $stats['wt']['total'] / 1000,
				'%real' => $stats['wt']['percent'],
				'cpu' => isset( $stats['cpu'] ) ? $stats['cpu']['total'] / 1000 : 0,
				'%cpu' => isset( $stats['cpu'] ) ? $stats['cpu']['percent'] : 0,
				'memory' => isset( $stats['mu'] ) ? $stats['mu']['total'] : 0,
				'%memory' => isset( $stats['mu'] ) ? $stats['mu']['percent'] : 0,
				'min_real' => $stats['wt']['min'] / 1000,
				'max_real' => $stats['wt']['max'] / 1000
			];
			$profile[] = $entry;
			if ( $fname === 'main()' ) {
				$main = $entry;
			}
		}

		// Merge in all of the custom profile sections
		foreach ( $this->sprofiler->getFunctionStats() as $stats ) {
			if ( $this->shouldExclude( $stats['name'] ) ) {
				continue;
			}

			// @note: getFunctionStats() values already in ms
			$stats['%real'] = $main['real'] ? $stats['real'] / $main['real'] * 100 : 0;
			$stats['%cpu'] = $main['cpu'] ? $stats['cpu'] / $main['cpu'] * 100 : 0;
			$stats['%memory'] = $main['memory'] ? $stats['memory'] / $main['memory'] * 100 : 0;
			$profile[] = $stats; // assume no section names collide with $metrics
		}

		return $profile;
	}

	/**
	 * Returns a profiling output to be stored in debug file
	 *
	 * @return string
	 */
	public function getOutput() {
		return $this->getFunctionReport();
	}

	/**
	 * Get a report of profiled functions sorted by inclusive wall clock time
	 * in descending order.
	 *
	 * Each line of the report includes this data:
	 * - Function name
	 * - Number of times function was called
	 * - Total wall clock time spent in function in microseconds
	 * - Minimum wall clock time spent in function in microseconds
	 * - Average wall clock time spent in function in microseconds
	 * - Maximum wall clock time spent in function in microseconds
	 * - Percentage of total wall clock time spent in function
	 * - Total delta of memory usage from start to end of function in bytes
	 *
	 * @return string
	 */
	protected function getFunctionReport() {
		$data = $this->getFunctionStats();
		usort( $data, function( $a, $b ) {
			if ( $a['real'] === $b['real'] ) {
				return 0;
			}
			return ( $a['real'] > $b['real'] ) ? -1 : 1; // descending
		} );

		$width = 140;
		$nameWidth = $width - 65;
		$format = "%-{$nameWidth}s %6d %9d %9d %9d %9d %7.3f%% %9d";
		$out = [];
		$out[] = sprintf( "%-{$nameWidth}s %6s %9s %9s %9s %9s %7s %9s",
			'Name', 'Calls', 'Total', 'Min', 'Each', 'Max', '%', 'Mem'
		);
		foreach ( $data as $stats ) {
			$out[] = sprintf( $format,
				$stats['name'],
				$stats['calls'],
				$stats['real'] * 1000,
				$stats['min_real'] * 1000,
				$stats['real'] / $stats['calls'] * 1000,
				$stats['max_real'] * 1000,
				$stats['%real'],
				$stats['memory']
			);
		}
		return implode( "\n", $out );
	}

	/**
	 * Retrieve raw data from xhprof
	 * @return array
	 */
	public function getRawData() {
		return $this->getXhprofData()->getRawData();
	}
}
