<?php
/**
 * @defgroup Profiler Profiler
 *
 * @file
 * @ingroup Profiler
 * This file is only included if profiling is enabled
 */

/** backward compatibility */
$wgProfiling = true;

/**
 * Begin profiling of a function
 * @param $functionname name of the function we will profile
 */
function wfProfileIn( $functionname ) {
	global $wgProfiler;
	$wgProfiler->profileIn( $functionname );
}

/**
 * Stop profiling of a function
 * @param $functionname name of the function we have profiled
 */
function wfProfileOut( $functionname = 'missing' ) {
	global $wgProfiler;
	$wgProfiler->profileOut( $functionname );
}

/**
 * Returns a profiling output to be stored in debug file
 *
 * @param $start Float
 * @param $elapsed Float: time elapsed since the beginning of the request
 */
function wfGetProfilingOutput( $start, $elapsed ) {
	global $wgProfiler;
	return $wgProfiler->getOutput( $start, $elapsed );
}

/**
 * Close opened profiling sections
 */
function wfProfileClose() {
	global $wgProfiler;
	$wgProfiler->close();
}

if (!function_exists('memory_get_usage')) {
	# Old PHP or --enable-memory-limit not compiled in
	function memory_get_usage() {
		return 0;
	}
}

/**
 * @ingroup Profiler
 * @todo document
 */
class Profiler {
	var $mStack = array (), $mWorkStack = array (), $mCollated = array ();
	var $mCalls = array (), $mTotals = array ();

	function __construct() {
		// Push an entry for the pre-profile setup time onto the stack
		global $wgRequestTime;
		if ( !empty( $wgRequestTime ) ) {
			$this->mWorkStack[] = array( '-total', 0, $wgRequestTime, 0 );
			$this->mStack[] = array( '-setup', 1, $wgRequestTime, 0, microtime(true), 0 );
		} else {
			$this->profileIn( '-total' );
		}
	}

	/**
	 * Called by wfProfieIn()
	 * @param $functionname string
	 */
	function profileIn( $functionname ) {
		global $wgDebugFunctionEntry, $wgProfiling;
		if( !$wgProfiling ) return;
		if( $wgDebugFunctionEntry ){
			$this->debug( str_repeat( ' ', count( $this->mWorkStack ) ) . 'Entering ' . $functionname . "\n" );
		}

		$this->mWorkStack[] = array( $functionname, count( $this->mWorkStack ), $this->getTime(), memory_get_usage() );
	}

	/**
	 * Called by wfProfieOut()
	 * @param $functionname string
	 */
	function profileOut($functionname) {
		global $wgDebugFunctionEntry, $wgProfiling;
		if( !$wgProfiling ) return;
		$memory = memory_get_usage();
		$time = $this->getTime();

		if( $wgDebugFunctionEntry ){
			$this->debug( str_repeat( ' ', count( $this->mWorkStack ) - 1 ) . 'Exiting ' . $functionname . "\n" );
		}

		$bit = array_pop($this->mWorkStack);

		if (!$bit) {
			$this->debug("Profiling error, !\$bit: $functionname\n");
		} else {
			//if( $wgDebugProfiling ){
				if( $functionname == 'close' ){
					$message = "Profile section ended by close(): {$bit[0]}";
					$this->debug( "$message\n" );
					$this->mStack[] = array( $message, 0, '0 0', 0, '0 0', 0 );
				}
				elseif( $bit[0] != $functionname ){
					$message = "Profiling error: in({$bit[0]}), out($functionname)";
					$this->debug( "$message\n" );
					$this->mStack[] = array( $message, 0, '0 0', 0, '0 0', 0 );
				}
			//}
			$bit[] = $time;
			$bit[] = $memory;
			$this->mStack[] = $bit;
		}
	}

	/**
	 * called by wfProfileClose()
	 */
	function close() {
		global $wgProfiling;

		# Avoid infinite loop
		if( !$wgProfiling )
			return;

		while( count( $this->mWorkStack ) ){
			$this->profileOut( 'close' );
		}
	}

	/**
	 * called by wfGetProfilingOutput()
	 */
	function getOutput() {
		global $wgDebugFunctionEntry, $wgProfileCallTree;
		$wgDebugFunctionEntry = false;

		if( !count( $this->mStack ) && !count( $this->mCollated ) ){
			return "No profiling output\n";
		}
		$this->close();

		if( $wgProfileCallTree ) {
			global $wgProfileToDatabase;
			# XXX: We must call $this->getFunctionReport() to log to the DB
			if( $wgProfileToDatabase ) {
				$this->getFunctionReport();
			}
			return $this->getCallTree();
		} else {
			return $this->getFunctionReport();
		}
	}

	/**
	 * returns a tree of function call instead of a list of functions
	 */
	function getCallTree() {
		return implode( '', array_map( array( &$this, 'getCallTreeLine' ), $this->remapCallTree( $this->mStack ) ) );
	}

	/**
	 * Recursive function the format the current profiling array into a tree
	 *
	 * @param $stack profiling array
	 */
	function remapCallTree( $stack ) {
		if( count( $stack ) < 2 ){
			return $stack;
		}
		$outputs = array ();
		for( $max = count( $stack ) - 1; $max > 0; ){
			/* Find all items under this entry */
			$level = $stack[$max][1];
			$working = array ();
			for( $i = $max -1; $i >= 0; $i-- ){
				if( $stack[$i][1] > $level ){
					$working[] = $stack[$i];
				} else {
					break;
				}
			}
			$working = $this->remapCallTree( array_reverse( $working ) );
			$output = array();
			foreach( $working as $item ){
				array_push( $output, $item );
			}
			array_unshift( $output, $stack[$max] );
			$max = $i;

			array_unshift( $outputs, $output );
		}
		$final = array();
		foreach( $outputs as $output ){
			foreach( $output as $item ){
				$final[] = $item;
			}
		}
		return $final;
	}

	/**
	 * Callback to get a formatted line for the call tree
	 */
	function getCallTreeLine( $entry ) {
		list( $fname, $level, $start, /* $x */, $end)  = $entry;
		$delta = $end - $start;
		$space = str_repeat(' ', $level);
		# The ugly double sprintf is to work around a PHP bug,
		# which has been fixed in recent releases.
		return sprintf( "%10s %s %s\n", trim( sprintf( "%7.3f", $delta * 1000.0 ) ), $space, $fname );
	}

	function getTime() {
		return microtime(true);
		#return $this->getUserTime();
	}

	function getUserTime() {
		$ru = getrusage();
		return $ru['ru_utime.tv_sec'].' '.$ru['ru_utime.tv_usec'] / 1e6;
	}

	/**
	 * Returns a list of profiled functions.
	 * Also log it into the database if $wgProfileToDatabase is set to true.
	 */
	function getFunctionReport() {
		global $wgProfileToDatabase;

		$width = 140;
		$nameWidth = $width - 65;
		$format =      "%-{$nameWidth}s %6d %13.3f %13.3f %13.3f%% %9d  (%13.3f -%13.3f) [%d]\n";
		$titleFormat = "%-{$nameWidth}s %6s %13s %13s %13s %9s\n";
		$prof = "\nProfiling data\n";
		$prof .= sprintf( $titleFormat, 'Name', 'Calls', 'Total', 'Each', '%', 'Mem' );
		$this->mCollated = array ();
		$this->mCalls = array ();
		$this->mMemory = array ();

		# Estimate profiling overhead
		$profileCount = count($this->mStack);
		wfProfileIn( '-overhead-total' );
		for( $i = 0; $i < $profileCount; $i ++ ){
			wfProfileIn( '-overhead-internal' );
			wfProfileOut( '-overhead-internal' );
		}
		wfProfileOut( '-overhead-total' );

		# First, subtract the overhead!
		$overheadTotal = $overheadMemory = $overheadInternal = array();
		foreach( $this->mStack as $entry ){
			$fname = $entry[0];
			$start = $entry[2];
			$end = $entry[4];
			$elapsed = $end - $start;
			$memory = $entry[5] - $entry[3];

			if( $fname == '-overhead-total' ){
				$overheadTotal[] = $elapsed;
				$overheadMemory[] = $memory;
			}
			elseif( $fname == '-overhead-internal' ){
				$overheadInternal[] = $elapsed;
			}
		}
		$overheadTotal = array_sum( $overheadTotal ) / count( $overheadInternal );
		$overheadMemory = array_sum( $overheadMemory ) / count( $overheadInternal );
		$overheadInternal = array_sum( $overheadInternal ) / count( $overheadInternal );

		# Collate
		foreach( $this->mStack as $index => $entry ){
			$fname = $entry[0];
			$start = $entry[2];
			$end = $entry[4];
			$elapsed = $end - $start;

			$memory = $entry[5] - $entry[3];
			$subcalls = $this->calltreeCount( $this->mStack, $index );

			if( !preg_match( '/^-overhead/', $fname ) ){
				# Adjust for profiling overhead (except special values with elapsed=0
				if( $elapsed ) {
					$elapsed -= $overheadInternal;
					$elapsed -= ($subcalls * $overheadTotal);
					$memory -= ($subcalls * $overheadMemory);
				}
			}

			if( !array_key_exists( $fname, $this->mCollated ) ){
				$this->mCollated[$fname] = 0;
				$this->mCalls[$fname] = 0;
				$this->mMemory[$fname] = 0;
				$this->mMin[$fname] = 1 << 24;
				$this->mMax[$fname] = 0;
				$this->mOverhead[$fname] = 0;
			}

			$this->mCollated[$fname] += $elapsed;
			$this->mCalls[$fname]++;
			$this->mMemory[$fname] += $memory;
			$this->mMin[$fname] = min($this->mMin[$fname], $elapsed);
			$this->mMax[$fname] = max($this->mMax[$fname], $elapsed);
			$this->mOverhead[$fname] += $subcalls;
		}

		$total = @$this->mCollated['-total'];
		$this->mCalls['-overhead-total'] = $profileCount;

		# Output
		arsort( $this->mCollated, SORT_NUMERIC );
		foreach( $this->mCollated as $fname => $elapsed ){
			$calls = $this->mCalls[$fname];
			$percent = $total ? 100. * $elapsed / $total : 0;
			$memory = $this->mMemory[$fname];
			$prof .= sprintf($format, substr($fname, 0, $nameWidth), $calls, (float) ($elapsed * 1000), (float) ($elapsed * 1000) / $calls, $percent, $memory, ($this->mMin[$fname] * 1000.0), ($this->mMax[$fname] * 1000.0), $this->mOverhead[$fname]);
			# Log to the DB
			if( $wgProfileToDatabase ) {
				self::logToDB($fname, (float) ($elapsed * 1000), $calls, (float) ($memory) );
			}
		}
		$prof .= "\nTotal: $total\n\n";

		return $prof;
	}

	/**
	 * Counts the number of profiled function calls sitting under
	 * the given point in the call graph. Not the most efficient algo.
	 *
	 * @param $stack Array:
	 * @param $start Integer:
	 * @return Integer
	 * @private
	 */
	function calltreeCount($stack, $start) {
		$level = $stack[$start][1];
		$count = 0;
		for ($i = $start -1; $i >= 0 && $stack[$i][1] > $level; $i --) {
			$count ++;
		}
		return $count;
	}

	/**
	 * Log a function into the database.
	 *
	 * @param $name string: function name
	 * @param $timeSum float
	 * @param $eventCount int: number of times that function was called
	 */
	static function logToDB( $name, $timeSum, $eventCount, $memorySum ){
		# Do not log anything if database is readonly (bug 5375)
		if( wfReadOnly() ) { return; }

		global $wgProfilePerHost;

		$dbw = wfGetDB( DB_MASTER );
		if( !is_object( $dbw ) )
			return false;
		$errorState = $dbw->ignoreErrors( true );

		$name = substr($name, 0, 255);

		if( $wgProfilePerHost ){
			$pfhost = wfHostname();
		} else {
			$pfhost = '';
		}
		
		// Kludge
		$timeSum = ($timeSum >= 0) ? $timeSum : 0;
		$memorySum = ($memorySum >= 0) ? $memorySum : 0;

		$dbw->update( 'profiling',
			array(
				"pf_count=pf_count+{$eventCount}",
				"pf_time=pf_time+{$timeSum}",
				"pf_memory=pf_memory+{$memorySum}",
			),
			array(
				'pf_name' => $name,
				'pf_server' => $pfhost,
			),
			__METHOD__ );
				

		$rc = $dbw->affectedRows();
		if ($rc == 0) {
			$dbw->insert('profiling', array ('pf_name' => $name, 'pf_count' => $eventCount,
				'pf_time' => $timeSum, 'pf_memory' => $memorySum, 'pf_server' => $pfhost ), 
				__METHOD__, array ('IGNORE'));
		}
		// When we upgrade to mysql 4.1, the insert+update
		// can be merged into just a insert with this construct added:
		//     "ON DUPLICATE KEY UPDATE ".
		//     "pf_count=pf_count + VALUES(pf_count), ".
		//     "pf_time=pf_time + VALUES(pf_time)";
		$dbw->ignoreErrors( $errorState );
	}

	/**
	 * Get the function name of the current profiling section
	 */
	function getCurrentSection() {
		$elt = end( $this->mWorkStack );
		return $elt[0];
	}

	/**
	 * Get function caller
	 * @param $level int
	 */
	static function getCaller( $level ) {
		$backtrace = wfDebugBacktrace();
		if ( isset( $backtrace[$level] ) ) {
			if ( isset( $backtrace[$level]['class'] ) ) {
				$caller = $backtrace[$level]['class'] . '::' . $backtrace[$level]['function'];
			} else {
				$caller = $backtrace[$level]['function'];
			}
		} else {
			$caller = 'unknown';
		}
		return $caller;
	}

	/**
	 * Add an entry in the debug log file
	 * @param $s string to output
	 */
	function debug( $s ) {
		if( function_exists( 'wfDebug' ) ) {
			wfDebug( $s );
		}
	}
}