Legoktm has uploaded a new change for review.

  https://gerrit.wikimedia.org/r/313646

Change subject: Add wikimedia/wait-condition-loop v1.0.1
......................................................................

Add wikimedia/wait-condition-loop v1.0.1

Bug: T146256
Change-Id: Ia84774d83da79fea1e167fe065c69549981f753b
---
M composer.json
M composer.lock
M composer/autoload_classmap.php
M composer/installed.json
A wikimedia/wait-condition-loop/COPYING
A wikimedia/wait-condition-loop/README.md
A wikimedia/wait-condition-loop/src/WaitConditionLoop.php
7 files changed, 678 insertions(+), 2 deletions(-)


  git pull ssh://gerrit.wikimedia.org:29418/mediawiki/vendor 
refs/changes/46/313646/1

diff --git a/composer.json b/composer.json
index 62a5d31..34f1ffa 100644
--- a/composer.json
+++ b/composer.json
@@ -45,6 +45,7 @@
                "wikimedia/scoped-callback": "1.0.0",
                "wikimedia/textcat": "1.1.3",
                "wikimedia/utfnormal": "1.0.3",
+               "wikimedia/wait-condition-loop": "1.0.1",
                "wikimedia/wrappedstring": "2.2.0",
                "zordius/lightncandy": "0.23"
        }
diff --git a/composer.lock b/composer.lock
index fc3258b..05d57b9 100644
--- a/composer.lock
+++ b/composer.lock
@@ -4,8 +4,8 @@
         "Read more about it at 
https://getcomposer.org/doc/01-basic-usage.md#composer-lock-the-lock-file";,
         "This file is @generated automatically"
     ],
-    "hash": "8c8277395b9ae35379e68a698fd79f14",
-    "content-hash": "6a30e5373c319d134704ebae9e2c7236",
+    "hash": "eb48dbe45827add41f49b7253513f912",
+    "content-hash": "d685c97157a41f98d586a2fd7df50044",
     "packages": [
         {
             "name": "composer/semver",
@@ -1770,6 +1770,48 @@
             "time": "2015-08-29 14:13:27"
         },
         {
+            "name": "wikimedia/wait-condition-loop",
+            "version": "v1.0.1",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/wikimedia/WaitConditionLoop.git";,
+                "reference": "0321b8ca6a0f701f96e04e5e8e6d3e244ab05338"
+            },
+            "dist": {
+                "type": "zip",
+                "url": 
"https://api.github.com/repos/wikimedia/WaitConditionLoop/zipball/0321b8ca6a0f701f96e04e5e8e6d3e244ab05338";,
+                "reference": "0321b8ca6a0f701f96e04e5e8e6d3e244ab05338",
+                "shasum": ""
+            },
+            "require": {
+                "php": ">=5.5.9"
+            },
+            "require-dev": {
+                "jakub-onderka/php-parallel-lint": "0.9.2",
+                "mediawiki/mediawiki-codesniffer": "0.7.2",
+                "phpunit/phpunit": "4.8.24"
+            },
+            "type": "library",
+            "autoload": {
+                "classmap": [
+                    "src/"
+                ]
+            },
+            "notification-url": "https://packagist.org/downloads/";,
+            "license": [
+                "GPL-2.0+"
+            ],
+            "authors": [
+                {
+                    "name": "Aaron Schulz",
+                    "email": "[email protected]"
+                }
+            ],
+            "description": "Wait loop that reaches a condition or times out",
+            "homepage": "https://www.mediawiki.org/wiki/WaitConditionLoop";,
+            "time": "2016-10-01 06:58:30"
+        },
+        {
             "name": "wikimedia/wrappedstring",
             "version": "v2.2.0",
             "source": {
diff --git a/composer/autoload_classmap.php b/composer/autoload_classmap.php
index b834147..c279cff 100644
--- a/composer/autoload_classmap.php
+++ b/composer/autoload_classmap.php
@@ -632,6 +632,7 @@
     'Wikimedia\\Composer\\Merge\\StabilityFlags' => $vendorDir . 
'/wikimedia/composer-merge-plugin/src/Merge/StabilityFlags.php',
     'Wikimedia\\PhpSessionSerializer' => $vendorDir . 
'/wikimedia/php-session-serializer/src/Wikimedia/PhpSessionSerializer.php',
     'Wikimedia\\ScopedCallback' => $vendorDir . 
'/wikimedia/scoped-callback/src/ScopedCallback.php',
+    'Wikimedia\\WaitConditionLoop' => $vendorDir . 
'/wikimedia/wait-condition-loop/src/WaitConditionLoop.php',
     'WrappedString\\WrappedString' => $vendorDir . 
'/wikimedia/wrappedstring/src/WrappedString.php',
     'WrappedString\\WrappedStringList' => $vendorDir . 
'/wikimedia/wrappedstring/src/WrappedStringList.php',
     'lessc' => $vendorDir . '/oyejorge/less.php/lessc.inc.php',
diff --git a/composer/installed.json b/composer/installed.json
index a05c19e..d565246 100644
--- a/composer/installed.json
+++ b/composer/installed.json
@@ -1923,5 +1923,49 @@
         ],
         "description": "Class for asserting that a callback happens when a 
dummy object leaves scope",
         "homepage": "https://www.mediawiki.org/wiki/ScopedCallback";
+    },
+    {
+        "name": "wikimedia/wait-condition-loop",
+        "version": "v1.0.1",
+        "version_normalized": "1.0.1.0",
+        "source": {
+            "type": "git",
+            "url": "https://github.com/wikimedia/WaitConditionLoop.git";,
+            "reference": "0321b8ca6a0f701f96e04e5e8e6d3e244ab05338"
+        },
+        "dist": {
+            "type": "zip",
+            "url": 
"https://api.github.com/repos/wikimedia/WaitConditionLoop/zipball/0321b8ca6a0f701f96e04e5e8e6d3e244ab05338";,
+            "reference": "0321b8ca6a0f701f96e04e5e8e6d3e244ab05338",
+            "shasum": ""
+        },
+        "require": {
+            "php": ">=5.5.9"
+        },
+        "require-dev": {
+            "jakub-onderka/php-parallel-lint": "0.9.2",
+            "mediawiki/mediawiki-codesniffer": "0.7.2",
+            "phpunit/phpunit": "4.8.24"
+        },
+        "time": "2016-10-01 06:58:30",
+        "type": "library",
+        "installation-source": "dist",
+        "autoload": {
+            "classmap": [
+                "src/"
+            ]
+        },
+        "notification-url": "https://packagist.org/downloads/";,
+        "license": [
+            "GPL-2.0+"
+        ],
+        "authors": [
+            {
+                "name": "Aaron Schulz",
+                "email": "[email protected]"
+            }
+        ],
+        "description": "Wait loop that reaches a condition or times out",
+        "homepage": "https://www.mediawiki.org/wiki/WaitConditionLoop";
     }
 ]
diff --git a/wikimedia/wait-condition-loop/COPYING 
b/wikimedia/wait-condition-loop/COPYING
new file mode 100644
index 0000000..d159169
--- /dev/null
+++ b/wikimedia/wait-condition-loop/COPYING
@@ -0,0 +1,339 @@
+                    GNU GENERAL PUBLIC LICENSE
+                       Version 2, June 1991
+
+ Copyright (C) 1989, 1991 Free Software Foundation, Inc.,
+ 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ Everyone is permitted to copy and distribute verbatim copies
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+
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diff --git a/wikimedia/wait-condition-loop/README.md 
b/wikimedia/wait-condition-loop/README.md
new file mode 100644
index 0000000..0c05686
--- /dev/null
+++ b/wikimedia/wait-condition-loop/README.md
@@ -0,0 +1,60 @@
+[![Latest Stable 
Version]](https://packagist.org/packages/wikimedia/wait-condition-loop) 
[![License]](https://packagist.org/packages/wikimedia/wait-condition-loop)
+
+Wait Condition Loop for PHP
+===========================
+
+This class is used for waiting on a condition to be reached, with the ability
+to specify a timeout. The condition is considered reached when the condition 
callback
+returns CONDITION_REACHED or true. CONDITION_ABORTED can also be used to stop 
the loop.
+
+Additionally, "work" callbacks can be injected to prepare useful work instead 
of simply
+having the current thread sleep or block on I/O. The loop will run one of 
these callbacks
+on each iteration of checking the condition callback, as long as there are any 
left to run.
+
+The loop class will automatically either retry the condition or usleep() 
before retrying it,
+depending on CPU usage. Low CPU usage and significant real-time passage is 
used to detect
+whether the condition callback appears to use blocking I/O. Use of usleep() 
will not occur
+until all of the "work" callbacks have run. This means that the condition 
callback can
+either be an "instant" CPU-bound check or a blocking I/O call with a small 
timeout. Both
+cases should automatically work without CPU intensive spin loops.
+
+Additional documentation about the library can be found on
+[MediaWiki.org](https://www.mediawiki.org/wiki/WaitConditionLoop).
+
+
+Usage
+-----
+       // Pre-compute some value that will be needed later
+       $result = null;
+       $workCallback = function () use ( &$result ) {
+               $result = ( $result !== null ) ? $result : $this->doWork();
+
+               return $result
+       }
+
+       $loop = new WaitConditionLoop(
+               function () use ( ... ) {
+                       if ( ... ) {
+                               // Condition reached; stop loop
+                               return WaitConditionLoop::CONDITION_REACHED;
+                       }
+                       // Condition not reached; keep checking
+                       return WaitConditionLoop::CONDITION_CONTINUE;
+               },
+               3.0, // timeout in seconds
+               [ $workCallback ]
+       );
+       $status = $loop->invoke(); // CONDITION_* constant
+
+       // Call $workCallback as needed later
+
+Running tests
+-------------
+
+    composer install --prefer-dist
+    composer test
+
+
+---
+[Latest Stable Version]: 
https://poser.pugx.org/wikimedia/wait-condition-loop/v/stable.svg
+[License]: https://poser.pugx.org/wikimedia/wait-condition-loop/license.svg
diff --git a/wikimedia/wait-condition-loop/src/WaitConditionLoop.php 
b/wikimedia/wait-condition-loop/src/WaitConditionLoop.php
new file mode 100644
index 0000000..583ebb3
--- /dev/null
+++ b/wikimedia/wait-condition-loop/src/WaitConditionLoop.php
@@ -0,0 +1,189 @@
+<?php
+/**
+ * Wait loop that reaches a condition or times out.
+ *
+ * Copyright (C) 2016 Aaron Schulz <[email protected]>
+ *
+ * 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
+ * @author Aaron Schulz
+ */
+
+namespace Wikimedia;
+
+/**
+ * Wait loop that reaches a condition or times out
+ */
+class WaitConditionLoop {
+       /** @var callable */
+       private $condition;
+       /** @var callable[] */
+       private $busyCallbacks = [];
+       /** @var float Seconds */
+       private $timeout;
+       /** @var float Seconds */
+       private $lastWaitTime;
+       /** @var integer|null */
+       private $rusageMode;
+
+       const CONDITION_REACHED = 1;
+       const CONDITION_CONTINUE = 0; // evaluates as falsey
+       const CONDITION_FAILED = -1;
+       const CONDITION_TIMED_OUT = -2;
+       const CONDITION_ABORTED = -3;
+
+       /**
+        * @param callable $condition Callback that returns a 
WaitConditionLoop::CONDITION_ constant
+        * @param float $timeout Timeout in seconds
+        * @param array &$busyCallbacks List of callbacks to do useful work (by 
reference)
+        */
+       public function __construct( callable $condition, $timeout = 5.0, 
&$busyCallbacks = [] ) {
+               $this->condition = $condition;
+               $this->timeout = $timeout;
+               $this->busyCallbacks =& $busyCallbacks;
+
+               if ( defined( 'HHVM_VERSION' ) && PHP_OS === 'Linux' ) {
+                       $this->rusageMode = 2; // RUSAGE_THREAD
+               } elseif ( function_exists( 'getrusage' ) ) {
+                       $this->rusageMode = 0; // RUSAGE_SELF
+               }
+       }
+
+       /**
+        * Invoke the loop and continue until either:
+        *   - a) The condition callback returns neither CONDITION_CONTINUE nor 
false
+        *   - b) The timeout is reached
+        * This a condition callback can return true (stop) or false (continue) 
for convenience.
+        * In such cases, the halting result of "true" will be converted to 
CONDITION_REACHED.
+        *
+        * If $timeout is 0, then only the condition callback will be called 
(no busy callbacks),
+        * and this will immediately return CONDITION_FAILED if the condition 
was not met.
+        *
+        * Exceptions in callbacks will be caught and the callback will be 
swapped with
+        * one that simply rethrows that exception back to the caller when 
invoked.
+        *
+        * @return integer WaitConditionLoop::CONDITION_* constant
+        * @throws \Exception Any error from the condition callback
+        */
+       public function invoke() {
+               $elapsed = 0.0; // seconds
+               $sleepUs = 0; // microseconds to sleep each time
+               $lastCheck = false;
+               $finalResult = self::CONDITION_TIMED_OUT;
+               do {
+                       $checkStartTime = $this->getWallTime();
+                       // Check if the condition is met yet
+                       $realStart = $this->getWallTime();
+                       $cpuStart = $this->getCpuTime();
+                       $checkResult = call_user_func( $this->condition );
+                       $cpu = $this->getCpuTime() - $cpuStart;
+                       $real = $this->getWallTime() - $realStart;
+                       // Exit if the condition is reached, an error occurs, 
or this is non-blocking
+                       if ( $this->timeout <= 0 ) {
+                               $finalResult = $checkResult ? 
self::CONDITION_REACHED : self::CONDITION_FAILED;
+                               break;
+                       } elseif ( (int)$checkResult !== 
self::CONDITION_CONTINUE ) {
+                               if ( is_int( $checkResult ) ) {
+                                       $finalResult = $checkResult;
+                               } else {
+                                       $finalResult = self::CONDITION_REACHED;
+                               }
+                               break;
+                       } elseif ( $lastCheck ) {
+                               break; // timeout reached
+                       }
+                       // Detect if condition callback seems to block or if 
justs burns CPU
+                       $conditionUsesInterrupts = ( $real > 0.100 && $cpu <= 
$real * .03 );
+                       if ( !$this->popAndRunBusyCallback() && 
!$conditionUsesInterrupts ) {
+                               // 10 queries = 10(10+100)/2 ms = 550ms, 14 
queries = 1050ms
+                               $sleepUs = min( $sleepUs + 10 * 1e3, 1e6 ); // 
stop incrementing at ~1s
+                               $this->usleep( $sleepUs );
+                       }
+                       $checkEndTime = $this->getWallTime();
+                       // The max() protects against the clock getting set back
+                       $elapsed += max( $checkEndTime - $checkStartTime, 0.010 
);
+                       // Do not let slow callbacks timeout without checking 
the condition one more time
+                       $lastCheck = ( $elapsed >= $this->timeout );
+               } while ( true );
+
+               $this->lastWaitTime = $elapsed;
+
+               return $finalResult;
+       }
+
+       /**
+        * @return float Seconds
+        */
+       public function getLastWaitTime() {
+               return $this->lastWaitTime;
+       }
+
+       /**
+        * @param integer $microseconds
+        */
+       protected function usleep( $microseconds ) {
+               usleep( $microseconds );
+       }
+
+       /**
+        * @return float
+        */
+       protected function getWallTime() {
+               return microtime( true );
+       }
+
+       /**
+        * @return float Returns 0.0 if not supported (Windows on PHP < 7)
+        */
+       protected function getCpuTime() {
+               if ( $this->rusageMode === null ) {
+                       return microtime( true ); // assume worst case (all 
time is CPU)
+               }
+
+               $ru = getrusage( $this->rusageMode );
+               $time = $ru['ru_utime.tv_sec'] + $ru['ru_utime.tv_usec'] / 1e6;
+               $time += $ru['ru_stime.tv_sec'] + $ru['ru_stime.tv_usec'] / 1e6;
+
+               return $time;
+       }
+
+       /**
+        * Run one of the callbacks that does work ahead of time for another 
caller
+        *
+        * @return bool Whether a callback was executed
+        */
+       private function popAndRunBusyCallback() {
+               if ( $this->busyCallbacks ) {
+                       reset( $this->busyCallbacks );
+                       $key = key( $this->busyCallbacks );
+                       /** @var callable $workCallback */
+                       $workCallback =& $this->busyCallbacks[$key];
+                       try {
+                               $workCallback();
+                       } catch ( \Exception $e ) {
+                               $workCallback = function () use ( $e ) {
+                                       throw $e;
+                               };
+                       }
+                       unset( $this->busyCallbacks[$key] ); // consume
+
+                       return true;
+               }
+
+               return false;
+       }
+}

-- 
To view, visit https://gerrit.wikimedia.org/r/313646
To unsubscribe, visit https://gerrit.wikimedia.org/r/settings

Gerrit-MessageType: newchange
Gerrit-Change-Id: Ia84774d83da79fea1e167fe065c69549981f753b
Gerrit-PatchSet: 1
Gerrit-Project: mediawiki/vendor
Gerrit-Branch: master
Gerrit-Owner: Legoktm <[email protected]>

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