ManagesTransactions::performRollBack()   A
last analyzed

Complexity

Conditions 3
Paths 3

Size

Total Lines 10
Code Lines 6

Duplication

Lines 0
Ratio 0 %

Importance

Changes 0
Metric Value
dl 0
loc 10
rs 9.4285
c 0
b 0
f 0
cc 3
eloc 6
nc 3
nop 1
1
<?php
2
namespace Childish\connection\traits;
3
4
use Closure;
5
use Exception;
6
use Throwable;
7
use Childish\support\Tools;
8
9
/**
10
 * ManagesTransactions
11
 *
12
 * @author    Pu ShaoWei <[email protected]>
13
 * @date      2017/12/7
14
 * @version   1.0
15
 */
16
trait ManagesTransactions
17
{
18
    /**
19
     * Execute a Closure within a transaction.
20
     *
21
     * @param  \Closure  $callback
22
     * @param  int  $attempts
23
     * @return mixed
24
     *
25
     * @throws \Exception|\Throwable
26
     */
27
    public function transaction(Closure $callback, $attempts = 1)
28
    {
29
        for ($currentAttempt = 1; $currentAttempt <= $attempts; $currentAttempt++) {
30
            $this->beginTransaction();
31
32
            // We'll simply execute the given callback within a try / catch block and if we
33
            // catch any exception we can rollback this transaction so that none of this
34
            // gets actually persisted to a database or stored in a permanent fashion.
35
            try {
36
                return $this->higherOrderTap($callback($this), function ($result) {
0 ignored issues
show
Bug introduced by
It seems like higherOrderTap() must be provided by classes using this trait. How about adding it as abstract method to this trait?

This check looks for methods that are used by a trait but not required by it.

To illustrate, let’s look at the following code example

trait Idable {
    public function equalIds(Idable $other) {
        return $this->getId() === $other->getId();
    }
}

The trait Idable provides a method equalsId that in turn relies on the method getId(). If this method does not exist on a class mixing in this trait, the method will fail.

Adding the getId() as an abstract method to the trait will make sure it is available.

Loading history...
Unused Code introduced by
The parameter $result is not used and could be removed.

This check looks from parameters that have been defined for a function or method, but which are not used in the method body.

Loading history...
37
                    $this->commit();
38
                });
39
            }
40
41
                // If we catch an exception we'll rollback this transaction and try again if we
42
                // are not out of attempts. If we are out of attempts we will just throw the
43
                // exception back out and let the developer handle an uncaught exceptions.
44
            catch (Exception $e) {
45
                $this->handleTransactionException(
46
                    $e, $currentAttempt, $attempts
47
                );
48
            } catch (Throwable $e) {
49
                $this->rollBack();
50
51
                throw $e;
52
            }
53
        }
54
    }
55
56
    /**
57
     * Handle an exception encountered when running a transacted statement.
58
     *
59
     * @param  \Exception  $e
60
     * @param  int  $currentAttempt
61
     * @param  int  $maxAttempts
62
     * @return void
63
     *
64
     * @throws \Exception
65
     */
66
    protected function handleTransactionException($e, $currentAttempt, $maxAttempts)
67
    {
68
        // On a deadlock, MySQL rolls back the entire transaction so we can't just
69
        // retry the query. We have to throw this exception all the way out and
70
        // let the developer handle it in another way. We will decrement too.
71
        if ($this->causedByDeadlock($e) &&
72
            $this->transactions > 1) {
73
            --$this->transactions;
0 ignored issues
show
Bug introduced by
The property transactions does not exist. Did you maybe forget to declare it?

In PHP it is possible to write to properties without declaring them. For example, the following is perfectly valid PHP code:

class MyClass { }

$x = new MyClass();
$x->foo = true;

Generally, it is a good practice to explictly declare properties to avoid accidental typos and provide IDE auto-completion:

class MyClass {
    public $foo;
}

$x = new MyClass();
$x->foo = true;
Loading history...
74
75
            throw $e;
76
        }
77
78
        // If there was an exception we will rollback this transaction and then we
79
        // can check if we have exceeded the maximum attempt count for this and
80
        // if we haven't we will return and try this query again in our loop.
81
        $this->rollBack();
82
83
        if ($this->causedByDeadlock($e) &&
84
            $currentAttempt < $maxAttempts) {
85
            return;
86
        }
87
88
        throw $e;
89
    }
90
91
    /**
92
     * Start a new database transaction.
93
     *
94
     * @return void
95
     * @throws \Exception
96
     */
97
    public function beginTransaction()
98
    {
99
        $this->createTransaction();
100
        ++$this->transactions;
101
    }
102
103
    /**
104
     * Create a transaction within the database.
105
     *
106
     * @return void
107
     */
108
    protected function createTransaction()
109
    {
110
        if ($this->transactions == 0) {
111
            try {
112
                $this->getPdo()->beginTransaction();
0 ignored issues
show
Bug introduced by
It seems like getPdo() must be provided by classes using this trait. How about adding it as abstract method to this trait?

This check looks for methods that are used by a trait but not required by it.

To illustrate, let’s look at the following code example

trait Idable {
    public function equalIds(Idable $other) {
        return $this->getId() === $other->getId();
    }
}

The trait Idable provides a method equalsId that in turn relies on the method getId(). If this method does not exist on a class mixing in this trait, the method will fail.

Adding the getId() as an abstract method to the trait will make sure it is available.

Loading history...
113
            } catch (Exception $e) {
114
                $this->handleBeginTransactionException($e);
115
            }
116
        } elseif ($this->transactions >= 1 && $this->queryGrammar->supportsSavepoints()) {
0 ignored issues
show
Bug introduced by
The property queryGrammar does not exist. Did you maybe forget to declare it?

In PHP it is possible to write to properties without declaring them. For example, the following is perfectly valid PHP code:

class MyClass { }

$x = new MyClass();
$x->foo = true;

Generally, it is a good practice to explictly declare properties to avoid accidental typos and provide IDE auto-completion:

class MyClass {
    public $foo;
}

$x = new MyClass();
$x->foo = true;
Loading history...
117
            $this->createSavepoint();
118
        }
119
    }
120
121
    /**
122
     * Create a save point within the database.
123
     *
124
     * @return void
125
     */
126
    protected function createSavepoint()
127
    {
128
        $this->getPdo()->exec(
0 ignored issues
show
Bug introduced by
It seems like getPdo() must be provided by classes using this trait. How about adding it as abstract method to this trait?

This check looks for methods that are used by a trait but not required by it.

To illustrate, let’s look at the following code example

trait Idable {
    public function equalIds(Idable $other) {
        return $this->getId() === $other->getId();
    }
}

The trait Idable provides a method equalsId that in turn relies on the method getId(). If this method does not exist on a class mixing in this trait, the method will fail.

Adding the getId() as an abstract method to the trait will make sure it is available.

Loading history...
129
            $this->queryGrammar->compileSavepoint('trans'.($this->transactions + 1))
130
        );
131
    }
132
133
    /**
134
     * Handle an exception from a transaction beginning.
135
     *
136
     * @param  \Exception  $e
137
     * @return void
138
     *
139
     * @throws \Exception
140
     */
141
    protected function handleBeginTransactionException($e)
142
    {
143
        if ($this->causedByLostConnection($e)) {
0 ignored issues
show
Bug introduced by
It seems like causedByLostConnection() must be provided by classes using this trait. How about adding it as abstract method to this trait?

This check looks for methods that are used by a trait but not required by it.

To illustrate, let’s look at the following code example

trait Idable {
    public function equalIds(Idable $other) {
        return $this->getId() === $other->getId();
    }
}

The trait Idable provides a method equalsId that in turn relies on the method getId(). If this method does not exist on a class mixing in this trait, the method will fail.

Adding the getId() as an abstract method to the trait will make sure it is available.

Loading history...
144
            $this->reconnect();
0 ignored issues
show
Bug introduced by
It seems like reconnect() must be provided by classes using this trait. How about adding it as abstract method to this trait?

This check looks for methods that are used by a trait but not required by it.

To illustrate, let’s look at the following code example

trait Idable {
    public function equalIds(Idable $other) {
        return $this->getId() === $other->getId();
    }
}

The trait Idable provides a method equalsId that in turn relies on the method getId(). If this method does not exist on a class mixing in this trait, the method will fail.

Adding the getId() as an abstract method to the trait will make sure it is available.

Loading history...
145
146
            $this->pdo->beginTransaction();
0 ignored issues
show
Bug introduced by
The property pdo does not exist. Did you maybe forget to declare it?

In PHP it is possible to write to properties without declaring them. For example, the following is perfectly valid PHP code:

class MyClass { }

$x = new MyClass();
$x->foo = true;

Generally, it is a good practice to explictly declare properties to avoid accidental typos and provide IDE auto-completion:

class MyClass {
    public $foo;
}

$x = new MyClass();
$x->foo = true;
Loading history...
147
        } else {
148
            throw $e;
149
        }
150
    }
151
152
    /**
153
     * Commit the active database transaction.
154
     *
155
     * @return void
156
     */
157
    public function commit()
158
    {
159
        if ($this->transactions == 1) {
160
            $this->getPdo()->commit();
0 ignored issues
show
Bug introduced by
It seems like getPdo() must be provided by classes using this trait. How about adding it as abstract method to this trait?

This check looks for methods that are used by a trait but not required by it.

To illustrate, let’s look at the following code example

trait Idable {
    public function equalIds(Idable $other) {
        return $this->getId() === $other->getId();
    }
}

The trait Idable provides a method equalsId that in turn relies on the method getId(). If this method does not exist on a class mixing in this trait, the method will fail.

Adding the getId() as an abstract method to the trait will make sure it is available.

Loading history...
161
        }
162
163
        $this->transactions = max(0, $this->transactions - 1);
164
    }
165
166
    /**
167
     * Rollback the active database transaction.
168
     *
169
     * @param  int|null  $toLevel
170
     * @return void
171
     */
172
    public function rollBack($toLevel = null)
173
    {
174
        // We allow developers to rollback to a certain transaction level. We will verify
175
        // that this given transaction level is valid before attempting to rollback to
176
        // that level. If it's not we will just return out and not attempt anything.
177
        $toLevel = is_null($toLevel)
178
            ? $this->transactions - 1
179
            : $toLevel;
180
181
        if ($toLevel < 0 || $toLevel >= $this->transactions) {
182
            return;
183
        }
184
185
        // Next, we will actually perform this rollback within this database and fire the
186
        // rollback event. We will also set the current transaction level to the given
187
        // level that was passed into this method so it will be right from here out.
188
        $this->performRollBack($toLevel);
189
190
        $this->transactions = $toLevel;
191
    }
192
193
    /**
194
     * Perform a rollback within the database.
195
     *
196
     * @param  int  $toLevel
197
     * @return void
198
     */
199
    protected function performRollBack($toLevel)
200
    {
201
        if ($toLevel == 0) {
202
            $this->getPdo()->rollBack();
0 ignored issues
show
Bug introduced by
It seems like getPdo() must be provided by classes using this trait. How about adding it as abstract method to this trait?

This check looks for methods that are used by a trait but not required by it.

To illustrate, let’s look at the following code example

trait Idable {
    public function equalIds(Idable $other) {
        return $this->getId() === $other->getId();
    }
}

The trait Idable provides a method equalsId that in turn relies on the method getId(). If this method does not exist on a class mixing in this trait, the method will fail.

Adding the getId() as an abstract method to the trait will make sure it is available.

Loading history...
203
        } elseif ($this->queryGrammar->supportsSavepoints()) {
204
            $this->getPdo()->exec(
0 ignored issues
show
Bug introduced by
It seems like getPdo() must be provided by classes using this trait. How about adding it as abstract method to this trait?

This check looks for methods that are used by a trait but not required by it.

To illustrate, let’s look at the following code example

trait Idable {
    public function equalIds(Idable $other) {
        return $this->getId() === $other->getId();
    }
}

The trait Idable provides a method equalsId that in turn relies on the method getId(). If this method does not exist on a class mixing in this trait, the method will fail.

Adding the getId() as an abstract method to the trait will make sure it is available.

Loading history...
205
                $this->queryGrammar->compileSavepointRollBack('trans'.($toLevel + 1))
206
            );
207
        }
208
    }
209
210
    /**
211
     * Get the number of active transactions.
212
     *
213
     * @return int
214
     */
215
    public function transactionLevel()
216
    {
217
        return $this->transactions;
218
    }
219
220
    /**
221
     * Determine if the given exception was caused by a deadlock.
222
     *
223
     * @param  \Exception  $e
224
     * @return bool
225
     */
226
    protected function causedByDeadlock(Exception $e)
227
    {
228
        $message = $e->getMessage();
229
        return Tools::contains($message, [
230
            'Deadlock found when trying to get lock',
231
            'deadlock detected',
232
            'The database file is locked',
233
            'database is locked',
234
            'database table is locked',
235
            'A table in the database is locked',
236
            'has been chosen as the deadlock victim',
237
            'Lock wait timeout exceeded; try restarting transaction',
238
        ]);
239
    }
240
}
241