fluentform / app / Services / Spout / Reader / XLSX / Helper / SharedStringsCaching / FileBasedStrategy.php

FileBasedStrategy.php in Fluent Forms – Customizable Contact Forms, Survey, Quiz, & Conversational Form Builder 6.2.5, at app/Services/Spout/Reader/XLSX/Helper/SharedStringsCaching/FileBasedStrategy.php

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1	<?php
2
3	namespace Box\Spout\Reader\XLSX\Helper\SharedStringsCaching;
4
5	use Box\Spout\Common\Helper\FileSystemHelper;
6	use Box\Spout\Common\Helper\GlobalFunctionsHelper;
7	use Box\Spout\Reader\Exception\SharedStringNotFoundException;
8
9	/**
10	* Class FileBasedStrategy
11	*
12	* This class implements the file-based caching strategy for shared strings.
13	* Shared strings are stored in small files (with a max number of strings per file).
14	* This strategy is slower than an in-memory strategy but is used to avoid out of memory crashes.
15	*
16	* @package Box\Spout\Reader\XLSX\Helper\SharedStringsCaching
17	*/
18	class FileBasedStrategy implements CachingStrategyInterface
19	{
20	/** Value to use to escape the line feed character ("\n") */
21	const ESCAPED_LINE_FEED_CHARACTER = '_x000A_';
22
23	/** @var \Box\Spout\Common\Helper\GlobalFunctionsHelper Helper to work with global functions */
24	protected $globalFunctionsHelper;
25
26	/** @var \Box\Spout\Common\Helper\FileSystemHelper Helper to perform file system operations */
27	protected $fileSystemHelper;
28
29	/** @var string Temporary folder where the temporary files will be created */
30	protected $tempFolder;
31
32	/**
33	* @var int Maximum number of strings that can be stored in one temp file
34	* @see CachingStrategyFactory::MAX_NUM_STRINGS_PER_TEMP_FILE
35	*/
36	protected $maxNumStringsPerTempFile;
37
38	/** @var resource Pointer to the last temp file a shared string was written to */
39	protected $tempFilePointer;
40
41	/**
42	* @var string Path of the temporary file whose contents is currently stored in memory
43	* @see CachingStrategyFactory::MAX_NUM_STRINGS_PER_TEMP_FILE
44	*/
45	protected $inMemoryTempFilePath;
46
47	/**
48	* @var array Contents of the temporary file that was last read
49	* @see CachingStrategyFactory::MAX_NUM_STRINGS_PER_TEMP_FILE
50	*/
51	protected $inMemoryTempFileContents;
52
53	/**
54	* @param string\|null $tempFolder Temporary folder where the temporary files to store shared strings will be stored
55	* @param int $maxNumStringsPerTempFile Maximum number of strings that can be stored in one temp file
56	*/
57	public function __construct($tempFolder, $maxNumStringsPerTempFile)
58	{
59	$rootTempFolder = ($tempFolder) ?: sys_get_temp_dir();
60	$this->fileSystemHelper = new FileSystemHelper($rootTempFolder);
61	$this->tempFolder = $this->fileSystemHelper->createFolder($rootTempFolder, uniqid('sharedstrings'));
62
63	$this->maxNumStringsPerTempFile = $maxNumStringsPerTempFile;
64
65	$this->globalFunctionsHelper = new GlobalFunctionsHelper();
66	$this->tempFilePointer = null;
67	}
68
69	/**
70	* Adds the given string to the cache.
71	*
72	* @param string $sharedString The string to be added to the cache
73	* @param int $sharedStringIndex Index of the shared string in the sharedStrings.xml file
74	* @return void
75	*/
76	public function addStringForIndex($sharedString, $sharedStringIndex)
77	{
78	$tempFilePath = $this->getSharedStringTempFilePath($sharedStringIndex);
79
80	if (!$this->globalFunctionsHelper->file_exists($tempFilePath)) {
81	if ($this->tempFilePointer) {
82	$this->globalFunctionsHelper->fclose($this->tempFilePointer);
83	}
84	$this->tempFilePointer = $this->globalFunctionsHelper->fopen($tempFilePath, 'w');
85	}
86
87	// The shared string retrieval logic expects each cell data to be on one line only
88	// Encoding the line feed character allows to preserve this assumption
89	$lineFeedEncodedSharedString = $this->escapeLineFeed($sharedString);
90
91	$this->globalFunctionsHelper->fwrite($this->tempFilePointer, $lineFeedEncodedSharedString . PHP_EOL);
92	}
93
94	/**
95	* Returns the path for the temp file that should contain the string for the given index
96	*
97	* @param int $sharedStringIndex Index of the shared string in the sharedStrings.xml file
98	* @return string The temp file path for the given index
99	*/
100	protected function getSharedStringTempFilePath($sharedStringIndex)
101	{
102	$numTempFile = intval($sharedStringIndex / $this->maxNumStringsPerTempFile);
103	return $this->tempFolder . '/sharedstrings' . $numTempFile;
104	}
105
106	/**
107	* Closes the cache after the last shared string was added.
108	* This prevents any additional string from being added to the cache.
109	*
110	* @return void
111	*/
112	public function closeCache()
113	{
114	// close pointer to the last temp file that was written
115	if ($this->tempFilePointer) {
116	$this->globalFunctionsHelper->fclose($this->tempFilePointer);
117	}
118	}
119
120
121	/**
122	* Returns the string located at the given index from the cache.
123	*
124	* @param int $sharedStringIndex Index of the shared string in the sharedStrings.xml file
125	* @return string The shared string at the given index
126	* @throws \Box\Spout\Reader\Exception\SharedStringNotFoundException If no shared string found for the given index
127	*/
128	public function getStringAtIndex($sharedStringIndex)
129	{
130	$tempFilePath = $this->getSharedStringTempFilePath($sharedStringIndex);
131	$indexInFile = $sharedStringIndex % $this->maxNumStringsPerTempFile;
132
133	if (!$this->globalFunctionsHelper->file_exists($tempFilePath)) {
134	throw new SharedStringNotFoundException("Shared string temp file not found: $tempFilePath ; for index: $sharedStringIndex");
135	}
136
137	if ($this->inMemoryTempFilePath !== $tempFilePath) {
138	// free memory
139	unset($this->inMemoryTempFileContents);
140
141	$this->inMemoryTempFileContents = explode(PHP_EOL, $this->globalFunctionsHelper->file_get_contents($tempFilePath));
142	$this->inMemoryTempFilePath = $tempFilePath;
143	}
144
145	$sharedString = null;
146
147	// Using isset here because it is way faster than array_key_exists...
148	if (isset($this->inMemoryTempFileContents[$indexInFile])) {
149	$escapedSharedString = $this->inMemoryTempFileContents[$indexInFile];
150	$sharedString = $this->unescapeLineFeed($escapedSharedString);
151	}
152
153	if ($sharedString === null) {
154	throw new SharedStringNotFoundException("Shared string not found for index: $sharedStringIndex");
155	}
156
157	return rtrim($sharedString, PHP_EOL);
158	}
159
160	/**
161	* Escapes the line feed characters (\n)
162	*
163	* @param string $unescapedString
164	* @return string
165	*/
166	private function escapeLineFeed($unescapedString)
167	{
168	return str_replace("\n", self::ESCAPED_LINE_FEED_CHARACTER, $unescapedString);
169	}
170
171	/**
172	* Unescapes the line feed characters (\n)
173	*
174	* @param string $escapedString
175	* @return string
176	*/
177	private function unescapeLineFeed($escapedString)
178	{
179	return str_replace(self::ESCAPED_LINE_FEED_CHARACTER, "\n", $escapedString);
180	}
181
182	/**
183	* Destroys the cache, freeing memory and removing any created artifacts
184	*
185	* @return void
186	*/
187	public function clearCache()
188	{
189	if ($this->tempFolder) {
190	$this->fileSystemHelper->deleteFolderRecursively($this->tempFolder);
191	}
192	}
193	}
194