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MDL-44874 core: Move uuid generation to setuplib

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This commit is contained in:
Andrew Nicols 2015-03-25 10:55:03 +08:00
parent 20d38830ae
commit ad3532dea1
2 changed files with 47 additions and 33 deletions
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34
lib/classes/lock/db_record_lock_factory.php
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@ -103,41 +103,9 @@ class db_record_lock_factory implements lock_factory {
* to duplicates in a clustered environment (especially on VMs due to poor time precision). * to duplicates in a clustered environment (especially on VMs due to poor time precision).
*/ */
protected function generate_unique_token() { protected function generate_unique_token() {
$uuid = ''; return generate_uuid();
if (function_exists("uuid_create")) {
$context = null;
uuid_create($context);
uuid_make($context, UUID_MAKE_V4);
uuid_export($context, UUID_FMT_STR, $uuid);
} else {
// Fallback uuid generation based on:
// "http://www.php.net/manual/en/function.uniqid.php#94959".
$uuid = sprintf('%04x%04x-%04x-%04x-%04x-%04x%04x%04x',
// 32 bits for "time_low".
mt_rand(0, 0xffff), mt_rand(0, 0xffff),
// 16 bits for "time_mid".
mt_rand(0, 0xffff),
// 16 bits for "time_hi_and_version",
// four most significant bits holds version number 4.
mt_rand(0, 0x0fff) | 0x4000,
// 16 bits, 8 bits for "clk_seq_hi_res",
// 8 bits for "clk_seq_low",
// two most significant bits holds zero and one for variant DCE1.1.
mt_rand(0, 0x3fff) | 0x8000,
// 48 bits for "node".
mt_rand(0, 0xffff), mt_rand(0, 0xffff), mt_rand(0, 0xffff));
}
return trim($uuid);
} }
/** /**
* Create and get a lock * Create and get a lock
* @param string $resource - The identifier for the lock. Should use frankenstyle prefix. * @param string $resource - The identifier for the lock. Should use frankenstyle prefix.

46
lib/setuplib.php
View file

@ -575,6 +575,52 @@ function get_exception_info($ex) {
return $info; return $info;
} }
/**
* Generate a uuid.
*
* Unique is hard. Very hard. Attempt to use the PECL UUID functions if available, and if not then revert to
* constructing the uuid using mt_rand.
*
* It is important that this token is not solely based on time as this could lead
* to duplicates in a clustered environment (especially on VMs due to poor time precision).
*
* @return string The uuid.
*/
function generate_uuid() {
$uuid = '';
if (function_exists("uuid_create")) {
$context = null;
uuid_create($context);
uuid_make($context, UUID_MAKE_V4);
uuid_export($context, UUID_FMT_STR, $uuid);
} else {
// Fallback uuid generation based on:
// "http://www.php.net/manual/en/function.uniqid.php#94959".
$uuid = sprintf('%04x%04x-%04x-%04x-%04x-%04x%04x%04x',
// 32 bits for "time_low".
mt_rand(0, 0xffff), mt_rand(0, 0xffff),
// 16 bits for "time_mid".
mt_rand(0, 0xffff),
// 16 bits for "time_hi_and_version",
// four most significant bits holds version number 4.
mt_rand(0, 0x0fff) | 0x4000,
// 16 bits, 8 bits for "clk_seq_hi_res",
// 8 bits for "clk_seq_low",
// two most significant bits holds zero and one for variant DCE1.1.
mt_rand(0, 0x3fff) | 0x8000,
// 48 bits for "node".
mt_rand(0, 0xffff), mt_rand(0, 0xffff), mt_rand(0, 0xffff));
}
return trim($uuid);
}
/** /**
* Returns the Moodle Docs URL in the users language for a given 'More help' link. * Returns the Moodle Docs URL in the users language for a given 'More help' link.
* *