Source for file SafeStream.php

Documentation is available at SafeStream.php

1: <?php
2:
3: /**
4: * Nette Framework
5: *
6: * Copyright (c) 2004, 2009 David Grudl (http://davidgrudl.com)
7: *
8: * This source file is subject to the "Nette license" that is bundled
9: * with this package in the file license.txt.
10: *
11: * For more information please see https://nette.org
12: *
13: * @copyright Copyright (c) 2004, 2009 David Grudl
14: * @license https://nette.org/license Nette license
15: * @link https://nette.org
16: * @category Nette
17: * @package Nette\IO
18: * @version $Id$
19: */
20:
21:
22:
23: /**
24: * Thread safe / atomic file manipulation. Stream safe://
25: *
26: * <code>
27: * file_put_contents('safe://myfile.txt', $content);
28: *
29: * $content = file_get_contents('safe://myfile.txt');
30: *
31: * unlink('safe://myfile.txt');
32: * </code>
33: *
34: *
35: * @author David Grudl
36: * @copyright Copyright (c) 2004, 2009 David Grudl
37: * @package Nette\IO
38: */
39: final class SafeStream
40: {
41: /**
42: * Name of stream protocol - safe://
43: */
44: const PROTOCOL = 'safe';
45:
46: /**
47: * Current file handle.
48: */
49: private $handle;
50:
51: /**
52: * Renaming of temporary file.
53: */
54: private $filePath;
55: private $tempFile;
56:
57: /**
58: * Starting position in file (for appending).
59: */
60: private $startPos = 0;
61:
62: /**
63: * Write-error detected?
64: */
65: private $writeError = FALSE;
66:
67:
68:
69: /**
70: * Registers protocol 'safe://'.
71: *
72: * @return bool
73: */
74: public static function register()
75: {
76: return stream_wrapper_register(self::PROTOCOL, __CLASS__);
77: }
78:
79:
80:
81: /**
82: * Opens file.
83: *
84: * @param string file name with stream protocol
85: * @param string mode - see fopen()
86: * @param int STREAM_USE_PATH, STREAM_REPORT_ERRORS
87: * @param string full path
88: * @return bool TRUE on success or FALSE on failure
89: */
90: public function stream_open($path, $mode, $options, &$opened_path)
91: {
92: $path = substr($path, strlen(self::PROTOCOL)+3); // trim protocol safe://
93:
94: $flag = trim($mode, 'rwax+'); // text | binary mode
95: $mode = trim($mode, 'tb'); // mode
96: $use_path = (bool) (STREAM_USE_PATH & $options); // use include_path?
97:
98: $append = FALSE;
99:
100: switch ($mode) {
101: case 'r':
102: case 'r+':
103: // enter critical section: open and lock EXISTING file for reading/writing
104: $handle = @fopen($path, $mode.$flag, $use_path); // intentionally @
105: if (!$handle) return FALSE;
106: if (flock($handle, $mode == 'r' ? LOCK_SH : LOCK_EX)) {
107: $this->handle = $handle;
108: return TRUE;
109: }
110: fclose($handle);
111: return FALSE;
112:
113: case 'a':
114: case 'a+': $append = TRUE;
115: case 'w':
116: case 'w+':
117: // try enter critical section: open and lock EXISTING file for rewriting
118: $handle = @fopen($path, 'r+'.$flag, $use_path); // intentionally @
119:
120: if ($handle) {
121: if (flock($handle, LOCK_EX)) {
122: if ($append) {
123: fseek($handle, 0, SEEK_END);
124: $this->startPos = ftell($handle);
125: } else {
126: ftruncate($handle, 0);
127: }
128: $this->handle = $handle;
129: return TRUE;
130: }
131: fclose($handle);
132: }
133: // file doesn't exists, continue...
134: $mode{0} = 'x'; // x || x+
135:
136: case 'x':
137: case 'x+':
138: if (file_exists($path)) return FALSE;
139:
140: // create temporary file in the same directory
141: $tmp = '~~' . time() . '.tmp';
142:
143: // enter critical section: create temporary file
144: $handle = @fopen($path . $tmp, $mode . $flag, $use_path); // intentionally @
145: if ($handle) {
146: if (flock($handle, LOCK_EX)) {
147: $this->handle = $handle;
148: if (!@rename($path . $tmp, $path)) { // intentionally @
149: // rename later - for windows
150: $this->tempFile = realpath($path . $tmp);
151: $this->filePath = substr($this->tempFile, 0, -strlen($tmp));
152: }
153: return TRUE;
154: }
155: fclose($handle);
156: unlink($path . $tmp);
157: }
158: return FALSE;
159:
160: default:
161: trigger_error("Unsupported mode $mode", E_USER_WARNING);
162: return FALSE;
163: } // switch
164:
165: } // stream_open
166:
167:
168:
169: /**
170: * Closes file.
171: *
172: * @return void
173: */
174: public function stream_close()
175: {
176: if ($this->writeError) {
177: ftruncate($this->handle, $this->startPos);
178: }
179:
180: fclose($this->handle);
181:
182: // are we working with temporary file?
183: if ($this->tempFile) {
184: // try to rename temp file, otherwise delete temp file
185: if (!@rename($this->tempFile, $this->filePath)) { // intentionally @
186: unlink($this->tempFile);
187: }
188: }
189: }
190:
191:
192:
193: /**
194: * Reads up to length bytes from the file.
195: *
196: * @param int length
197: * @return string
198: */
199: public function stream_read($length)
200: {
201: return fread($this->handle, $length);
202: }
203:
204:
205:
206: /**
207: * Writes the string to the file.
208: *
209: * @param string data to write
210: * @return int number of bytes that were successfully stored
211: */
212: public function stream_write($data)
213: {
214: $len = strlen($data);
215: $res = fwrite($this->handle, $data, $len);
216:
217: if ($res !== $len) { // disk full?
218: $this->writeError = TRUE;
219: }
220:
221: return $res;
222: }
223:
224:
225:
226: /**
227: * Returns the position of the file.
228: *
229: * @return int
230: */
231: public function stream_tell()
232: {
233: return ftell($this->handle);
234: }
235:
236:
237:
238: /**
239: * Returns TRUE if the file pointer is at end-of-file.
240: *
241: * @return bool
242: */
243: public function stream_eof()
244: {
245: return feof($this->handle);
246: }
247:
248:
249:
250: /**
251: * Sets the file position indicator for the file.
252: *
253: * @param int position
254: * @param int see fseek()
255: * @return int Return TRUE on success
256: */
257: public function stream_seek($offset, $whence)
258: {
259: return fseek($this->handle, $offset, $whence) === 0; // ???
260: }
261:
262:
263:
264: /**
265: * Gets information about a file referenced by $this->handle.
266: *
267: * @return array
268: */
269: public function stream_stat()
270: {
271: return fstat($this->handle);
272: }
273:
274:
275:
276: /**
277: * Gets information about a file referenced by filename.
278: *
279: * @param string file name
280: * @param int STREAM_URL_STAT_LINK, STREAM_URL_STAT_QUIET
281: * @return array
282: */
283: public function url_stat($path, $flags)
284: {
285: // This is not thread safe
286: $path = substr($path, strlen(self::PROTOCOL)+3);
287: return ($flags & STREAM_URL_STAT_LINK) ? @lstat($path) : @stat($path); // intentionally @
288: }
289:
290:
291:
292: /**
293: * Deletes a file.
294: * On Windows unlink is not allowed till file is opened
295: *
296: * @param string file name with stream protocol
297: * @return bool TRUE on success or FALSE on failure
298: */
299: public function unlink($path)
300: {
301: $path = substr($path, strlen(self::PROTOCOL)+3);
302: return unlink($path);
303: }
304:
305: }

Source for file SafeStream.php

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