From 32f61016d368401890443efc861fff0032ac6c42 Mon Sep 17 00:00:00 2001
From: Michael <heluecht@pirati.ca>
Date: Sun, 4 Jun 2017 07:26:21 +0000
Subject: [PATCH] Overhauled "lock" functionality

---
 include/dbstructure.php |  2 +-
 include/lock.php        | 80 -----------------------------------------
 src/Util/Lock.php       | 62 ++++++++++++++++++++++++++++++++
 3 files changed, 63 insertions(+), 81 deletions(-)
 delete mode 100644 include/lock.php
 create mode 100644 src/Util/Lock.php

diff --git a/include/dbstructure.php b/include/dbstructure.php
index 441e7be7f7..1801288a45 100644
--- a/include/dbstructure.php
+++ b/include/dbstructure.php
@@ -1205,7 +1205,7 @@ function db_definition() {
 					"id" => array("type" => "int(11)", "not null" => "1", "extra" => "auto_increment", "primary" => "1"),
 					"name" => array("type" => "varchar(128)", "not null" => "1", "default" => ""),
 					"locked" => array("type" => "tinyint(1)", "not null" => "1", "default" => "0"),
-					"created" => array("type" => "datetime", "default" => NULL_DATE),
+					"pid" => array("type" => "int(10) unsigned", "not null" => "1", "default" => "0"),
 					),
 			"indexes" => array(
 					"PRIMARY" => array("id"),
diff --git a/include/lock.php b/include/lock.php
deleted file mode 100644
index 64f6319ef1..0000000000
--- a/include/lock.php
+++ /dev/null
@@ -1,80 +0,0 @@
-<?php
-
-// Provide some ability to lock a PHP function so that multiple processes
-// can't run the function concurrently
-if (! function_exists('lock_function')) {
-function lock_function($fn_name, $block = true, $wait_sec = 2, $timeout = 30) {
-	if ( $wait_sec == 0 )
-		$wait_sec = 2;	// don't let the user pick a value that's likely to crash the system
-
-	$got_lock = false;
-	$start = time();
-
-	do {
-		q("LOCK TABLE `locks` WRITE");
-		$r = q("SELECT `locked`, `created` FROM `locks` WHERE `name` = '%s' LIMIT 1",
-			dbesc($fn_name)
-		);
-
-		if ((dbm::is_result($r)) AND (!$r[0]['locked'] OR (strtotime($r[0]['created']) < time() - 3600))) {
-			q("UPDATE `locks` SET `locked` = 1, `created` = '%s' WHERE `name` = '%s'",
-				dbesc(datetime_convert()),
-				dbesc($fn_name)
-			);
-			$got_lock = true;
-		}
-		elseif (! dbm::is_result($r)) {
-			/// @TODO the Boolean value for count($r) should be equivalent to the Boolean value of $r
-			q("INSERT INTO `locks` (`name`, `created`, `locked`) VALUES ('%s', '%s', 1)",
-				dbesc($fn_name),
-				dbesc(datetime_convert())
-			);
-			$got_lock = true;
-		}
-
-		q("UNLOCK TABLES");
-
-		if (($block) && (! $got_lock))
-			sleep($wait_sec);
-
-	} while (($block) && (! $got_lock) && ((time() - $start) < $timeout));
-
-	logger('lock_function: function ' . $fn_name . ' with blocking = ' . $block . ' got_lock = ' . $got_lock . ' time = ' . (time() - $start), LOGGER_DEBUG);
-
-	return $got_lock;
-}}
-
-
-if (! function_exists('block_on_function_lock')) {
-function block_on_function_lock($fn_name, $wait_sec = 2, $timeout = 30) {
-	if ( $wait_sec == 0 )
-		$wait_sec = 2;	// don't let the user pick a value that's likely to crash the system
-
-	$start = time();
-
-	do {
-		$r = q("SELECT locked FROM locks WHERE name = '%s' LIMIT 1",
-			dbesc($fn_name)
-		);
-
-		if (dbm::is_result($r) && $r[0]['locked']) {
-			sleep($wait_sec);
-		}
-
-	} while (dbm::is_result($r) && $r[0]['locked'] && ((time() - $start) < $timeout));
-
-	return;
-}}
-
-
-if (! function_exists('unlock_function')) {
-function unlock_function($fn_name) {
-	$r = q("UPDATE `locks` SET `locked` = 0, `created` = '%s' WHERE `name` = '%s'",
-			dbesc(NULL_DATE),
-			dbesc($fn_name)
-	     );
-
-	logger('unlock_function: released lock for function ' . $fn_name, LOGGER_DEBUG);
-
-	return;
-}}
diff --git a/src/Util/Lock.php b/src/Util/Lock.php
new file mode 100644
index 0000000000..03e8545adf
--- /dev/null
+++ b/src/Util/Lock.php
@@ -0,0 +1,62 @@
+<?php
+
+namespace Friendica\Util;
+
+/**
+ * @file src/Util/Lock.php
+ * @brief Functions for preventing parallel execution of functions
+ *
+ */
+
+use dba;
+use dbm;
+
+/**
+ * @brief This class contain Functions for preventing parallel execution of functions
+ */
+class Lock {
+
+
+// Provide some ability to lock a PHP function so that multiple processes
+// can't run the function concurrently
+
+	public static function set($fn_name, $wait_sec = 2, $timeout = 30) {
+		if ($wait_sec == 0) {
+			$wait_sec = 2;
+		}
+
+		$got_lock = false;
+		$start = time();
+
+		do {
+			dba:p("LOCK TABLE `locks` WRITE");
+			$lock = dba::select('locks', array('locked'), array('name' => $fn_name), array('limit' => 1));
+
+			if ((dbm::is_result($lock)) AND !$lock['locked']) {
+				dba::update('locks', array('locked' => true), array('name' => $fn_name));
+				$got_lock = true;
+			} elseif (!dbm::is_result($lock)) {
+				dbm::insert('locks', array('name' => $fn_name, 'locked' => true));
+				$got_lock = true;
+			}
+
+			dbm::p("UNLOCK TABLES");
+
+			if (!$got_lock) {
+				sleep($wait_sec);
+			}
+		} while (!$got_lock AND ((time() - $start) < $timeout));
+
+		logger('lock_function: function ' . $fn_name . ' with blocking = ' . $block . ' got_lock = ' . $got_lock . ' time = ' . (time() - $start), LOGGER_DEBUG);
+
+		return $got_lock;
+	}
+
+	public static function remove($fn_name) {
+		dba::update('locks', array('locked' => false), array('name' => $fn_name));
+
+		logger('unlock_function: released lock for function ' . $fn_name, LOGGER_DEBUG);
+
+		return;
+	}
+}