128 lines
3.6 KiB
PHP
128 lines
3.6 KiB
PHP
<?php
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namespace SilverStripe\ORM\Connect;
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/**
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* TransactionManager decorator that adds virtual nesting support.
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* Because this is managed in PHP and not the database, it has the following limitations:
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* - Committing a nested transaction won't change anything until the parent transaction is committed
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* - Rolling back a nested transaction means that the parent transaction must be rolled backed
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*
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* DBAL describes this behaviour nicely in their docs: https://www.doctrine-project.org/projects/doctrine-dbal/en/2.8/reference/transactions.html#transaction-nesting
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*/
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class NestedTransactionManager implements TransactionManager
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{
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/**
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* @var int
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*/
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protected $transactionNesting = 0;
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/**
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* @var TransactionManager
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*/
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protected $child;
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/**
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* Set to true if all transactions must roll back to the parent
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* @var boolean
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*/
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protected $mustRollback = false;
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/**
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* Create a NestedTransactionManager
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* @param TransactionManager $child The transaction manager that will handle the topmost transaction
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*/
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public function __construct(TransactionManager $child)
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{
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$this->child = $child;
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}
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/**
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* Start a transaction
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* @throws DatabaseException on failure
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* @return bool True on success
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*/
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public function transactionStart($transactionMode = false, $sessionCharacteristics = false)
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{
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if ($this->transactionNesting <= 0) {
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$this->transactionNesting = 1;
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$this->child->transactionStart($transactionMode, $sessionCharacteristics);
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} else {
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if ($this->child->supportsSavepoints()) {
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$this->child->transactionSavepoint("nesting" . $this->transactionNesting);
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}
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$this->transactionNesting++;
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}
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}
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public function transactionEnd($chain = false)
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{
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if ($this->mustRollback) {
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throw new DatabaseException("Child transaction was rolled back, so parent can't be committed");
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}
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if ($this->transactionNesting < 1) {
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throw new DatabaseException("Not within a transaction, so can't commit");
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}
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$this->transactionNesting--;
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if ($this->transactionNesting === 0) {
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$this->child->transactionEnd();
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}
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if ($chain) {
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return $this->transactionStart();
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}
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}
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public function transactionRollback($savepoint = null)
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{
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if ($this->transactionNesting < 1) {
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throw new DatabaseException("Not within a transaction, so can't roll back");
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}
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if ($savepoint) {
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return $this->child->transactionRollback($savepoint);
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}
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$this->transactionNesting--;
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if ($this->transactionNesting === 0) {
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$this->child->transactionRollback();
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$this->mustRollback = false;
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} else {
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if ($this->child->supportsSavepoints()) {
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$this->child->transactionRollback("nesting" . $this->transactionNesting);
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$this->mustRollback = false;
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// Without savepoints, parent transactions must roll back if a child one has
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} else {
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$this->mustRollback = true;
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}
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}
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}
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/**
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* Return the depth of the transaction.
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*
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* @return int
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*/
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public function transactionDepth()
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{
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return $this->transactionNesting;
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}
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public function transactionSavepoint($savepoint)
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{
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return $this->child->transactionSavepoint($savepoint);
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}
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public function supportsSavepoints()
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{
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return $this->child->supportsSavepoints();
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}
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}
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