Result::all() - Code Metrics - Inspection of "introduce support for Indexers" - mindplay-dk/sql - Measure and Improve Code Quality continuously with Scrutinizer

Completed

Pull Request — master (#34)

by Rasmus

created 2017-02-23 13:55 UTC

Result::all() B

↳ Parent: Result

Complexity

Conditions	4
Paths	4

Size

Total Lines	23
Code Lines	9

Duplication

Lines	0
Ratio	0 %

Code Coverage

Tests	8
CRAP Score	4.0218

Importance

Changes

Metric	Value
dl	0
loc	23
ccs	8
cts	9
cp	0.8889
rs	8.7972
c	0
b	0
f	0
cc	4
eloc	9
nc	4
nop	0
crap	4.0218

<?php

namespace mindplay\sql\framework;

use Iterator;
use IteratorAggregate;
use RuntimeException;

/**
 * This class represents the result of fetching a `PreparedStatement`, e.g. the results of
 * a `SELECT` SQL query, and with Mappers being applied on-the-fly, in batches.
 *
 * It implements `IteratorAggregate`, allowing you to execute the query and iterate
 * over the result set with a `foreach` statement.
 */
class Result implements IteratorAggregate
{
    /**
     * @var PreparedStatement
     */
    private $statement;

    /**
     * @var int
     */
    private $batch_size;

    /**
     * @var Mapper[] list of Mappers to apply when fetching results
     */
    private $mappers;

    /**
     * @var Indexer|null
     */
    private $indexer = null;

    /**
     * @param PreparedStatement $statement  prepared statement
     * @param int               $batch_size batch-size (when fetching large result sets)
     * @param Mapper[]          $mappers    list of Mappers to apply while fetching results
     * @param Indexer|null      $indexer    optional Indexer (used to customize Generator keys)
     */
    public function __construct(PreparedStatement $statement, $batch_size, array $mappers, Indexer $indexer = null)
    {
        $this->statement = $statement;
        $this->batch_size = $batch_size;
        $this->mappers = $mappers;
        $this->indexer = $indexer;
    }

    /**
     * @return mixed|null first record of the record-set (or NULL, if the record-set is empty)
     */
    public function firstRow()
    {
        foreach ($this->createIterator(1) as $record) {
            return $record; // break from loop immediately after fetching the first record
        }

        return null;
    }

    /**
     * @return mixed|null first column value of the first record of the record-set (or NULL, if the record-set is empty)
     */
    public function firstCol()
    {
        foreach ($this->createIterator(1) as $record) {
            $keys = array_keys($record);

            return $record[$keys[0]]; // break from loop immediately after fetching the first record
        }

        return null;
    }

    /**
     * @return array all the records of the record-set
     *
     * @throws RuntimeException if the result-set contains overlapping keys (generated by an Indexer)
     */
    public function all()
    {
        if ($this->indexer === null) {
            return iterator_to_array($this->getIterator()); // performance optimization: no index-check required
        }

        // NOTE: an Indexer can generate duplicate keys, for example if a foreign key
        //       is used in a query that returns multiple records with the same key.
        //
        //       validate the result and throw an exception if we find a duplicate:

        $result = [];

        foreach ($this->getIterator() as $key => $record) {
            if (isset($result[$key])) {
                throw new RuntimeException("duplicate key: {$key}");
            }

            $result[$key] = $record;
        }

        return $result;
    }
    
    /**
     * Execute this Statement and return a Generator, so you can iterate over the results.
     *
     * This method implements `IteratorAggregate`, permitting you to iterate directly over
     * the resulting records (or objects) without explicitly having to call this method.
     *
     * @return Iterator
     */
    public function getIterator()
    {
        return $this->createIterator($this->batch_size);
    }

    /**
     * Create an Iterator with a given batch-size.
     *
     * @param int $batch_size batch-size when processing the result set
     *
     * @return Iterator
     */
    private function createIterator($batch_size)
    {
        $fetching = true;

        do {
            // fetch a batch of records:

            $batch = [];

            do {
                $record = $this->statement->fetch();

                if ($record) {

                    $batch[] = $record;
                } else {
                    if (count($batch) === 0) {
                        return; // last batch of records fetched
                    }

                    $fetching = false; // last record of batch fetched
                }
            } while ($fetching && (count($batch) < $batch_size));

            // apply Mappers to current batch of records:

            $num_records = count($batch);

            foreach ($this->mappers as $index => $mapper) {
                $batch = $mapper->map($batch);

                if (count($batch) !== $num_records) {
                    $count = count($batch);

                    throw new RuntimeException("Mapper #{$index} returned {$count} records, expected: {$num_records}");
                }
            }

            // return each record from the current batch:

            if ($this->indexer) {
                foreach ($batch as $record) {
                    $index = $this->indexer->index($record);

                    yield $index => $record;
                }
            } else {
                foreach ($batch as $record) {
                    yield $record;
                }
            }
        } while ($fetching);
    }
}


1		<?php
2
3		namespace mindplay\sql\framework;
4
5		use Iterator;
6		use IteratorAggregate;
7		use RuntimeException;
8
9		/**
10		* This class represents the result of fetching a `PreparedStatement`, e.g. the results of
11		* a `SELECT` SQL query, and with Mappers being applied on-the-fly, in batches.
12		*
13		* It implements `IteratorAggregate`, allowing you to execute the query and iterate
14		* over the result set with a `foreach` statement.
15		*/
16		class Result implements IteratorAggregate
17		{
18		/**
19		* @var PreparedStatement
20		*/
21		private $statement;
22
23		/**
24		* @var int
25		*/
26		private $batch_size;
27
28		/**
29		* @var Mapper[] list of Mappers to apply when fetching results
30		*/
31		private $mappers;
32
33		/**
34		* @var Indexer\|null
35		*/
36		private $indexer = null;
37
38		/**
39		* @param PreparedStatement $statement prepared statement
40		* @param int $batch_size batch-size (when fetching large result sets)
41		* @param Mapper[] $mappers list of Mappers to apply while fetching results
42		* @param Indexer\|null $indexer optional Indexer (used to customize Generator keys)
43		*/
44	1	public function __construct(PreparedStatement $statement, $batch_size, array $mappers, Indexer $indexer = null)
45		{
46	1	$this->statement = $statement;
47	1	$this->batch_size = $batch_size;
48	1	$this->mappers = $mappers;
49	1	$this->indexer = $indexer;
50	1	}
51
52		/**
53		* @return mixed\|null first record of the record-set (or NULL, if the record-set is empty)
54		*/
55	1	public function firstRow()
56		{
57	1	foreach ($this->createIterator(1) as $record) {
58	1	return $record; // break from loop immediately after fetching the first record
59		}
60
61		return null;
62		}
63
64		/**
65		* @return mixed\|null first column value of the first record of the record-set (or NULL, if the record-set is empty)
66		*/
67	1	public function firstCol()
68		{
69	1	foreach ($this->createIterator(1) as $record) {
70	1	$keys = array_keys($record);
71
72	1	return $record[$keys[0]]; // break from loop immediately after fetching the first record
73		}
74
75		return null;
76		}
77
78		/**
79		* @return array all the records of the record-set
80		*
81		* @throws RuntimeException if the result-set contains overlapping keys (generated by an Indexer)
82		*/
83	1	public function all()
84		{
85	1	if ($this->indexer === null) {
86	1	return iterator_to_array($this->getIterator()); // performance optimization: no index-check required
87		}
88
89		// NOTE: an Indexer can generate duplicate keys, for example if a foreign key
90		// is used in a query that returns multiple records with the same key.
91		//
92		// validate the result and throw an exception if we find a duplicate:
93
94	1	$result = [];
95
96	1	foreach ($this->getIterator() as $key => $record) {
97	1	if (isset($result[$key])) {
98		throw new RuntimeException("duplicate key: {$key}");
99		}
100
101	1	$result[$key] = $record;
102		}
103
104	1	return $result;
105		}
106
107		/**
108		* Execute this Statement and return a Generator, so you can iterate over the results.
109		*
110		* This method implements `IteratorAggregate`, permitting you to iterate directly over
111		* the resulting records (or objects) without explicitly having to call this method.
112		*
113		* @return Iterator
114		*/
115	1	public function getIterator()
116		{
117	1	return $this->createIterator($this->batch_size);
118		}
119
120		/**
121		* Create an Iterator with a given batch-size.
122		*
123		* @param int $batch_size batch-size when processing the result set
124		*
125		* @return Iterator
126		*/
127	1	private function createIterator($batch_size)
128		{
129	1	$fetching = true;
130
131		do {
132		// fetch a batch of records:
133
134	1	$batch = [];
135
136		do {
137	1	$record = $this->statement->fetch();
138
139	1	if ($record) {
		0 ignored issues – show Bug Best Practice introduced 2016-04-29 10:35 UTC by Report Bug Copy Issue Report The expression `$record` of type `array` is implicitly converted to a boolean; are you sure this is intended? If so, consider using `! empty($expr)` instead to make it clear that you intend to check for an array without elements. This check marks implicit conversions of arrays to boolean values in a comparison. While in PHP an empty array is considered to be equal (but not identical) to false, this is not always apparent. Consider making the comparison explicit by using `empty(..)` or `! empty(...)` instead. Loading history...
140	1	$batch[] = $record;
141		} else {
142	1	if (count($batch) === 0) {
143	1	return; // last batch of records fetched
144		}
145
146	1	$fetching = false; // last record of batch fetched
147		}
148	1	} while ($fetching && (count($batch) < $batch_size));
149
150		// apply Mappers to current batch of records:
151
152	1	$num_records = count($batch);
153
154	1	foreach ($this->mappers as $index => $mapper) {
155	1	$batch = $mapper->map($batch);
156
157	1	if (count($batch) !== $num_records) {
158		$count = count($batch);
159
160	1	throw new RuntimeException("Mapper #{$index} returned {$count} records, expected: {$num_records}");
161		}
162		}
163
164		// return each record from the current batch:
165
166	1	if ($this->indexer) {
167	1	foreach ($batch as $record) {
168	1	$index = $this->indexer->index($record);
169
170	1	yield $index => $record;
171		}
172		} else {
173	1	foreach ($batch as $record) {
174	1	yield $record;
175		}
176		}
177	1	} while ($fetching);
178	1	}
179		}
180

mindplay-dk / sql

Pull Request — master (#34)

Result::all() B

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