Move Lock to private namespace, add interface. Update PHPDoc.

1 files changed, 6 insertions, 253 deletions

diff --git a/lib/public/files/lock.php b/lib/public/files/lock.php
index 196134724d3..34d307e8939 100644
--- a/lib/public/files/lock.php
+++ b/lib/public/files/lock.php
@@ -18,169 +18,20 @@
 
 namespace OCP\Files;
 
-use OCP\Config;
-use OC\Files\Filesystem;
-
 /**
  * Class Lock
  * @package OC\Files
  */
-class Lock {
+interface Lock {
 	const READ = 1;
 	const WRITE = 2;
 
-	/** @var int $retries Number of lock retries to attempt */
-	public static $retries = 40;
-
-	/** @var int $retryInterval Milliseconds between retries */
-	public static $retryInterval = 50;
-
-	/** @var string $path Filename of the file as represented in storage */
-	protected $path;
-
-	/** @var array $stack A stack of lock data */
-	protected $stack = array();
-
-	/** @var resource $handle A file handle used to maintain a lock  */
-	protected $handle;
-
-	/** @var string $lockFile Filename of the lock file */
-	protected $lockFile;
-
-	/** @var resource $lockFileHandle The file handle used to maintain a lock on the lock file */
-	protected $lockFileHandle;
-
 	/**
 	 * Constructor for the lock instance
 	 * @param string $path Absolute pathname for a local file on which to obtain a lock
 	 */
-	public function __construct($path) {
-		$this->path = Filesystem::normalizePath($path);
-	}
-
-	protected function obtainReadLock($existingHandle = null) {
-		\OC_Log::write('lock', sprintf('INFO: Read lock requested for %s', $this->path), \OC_Log::DEBUG);
-		$timeout = Lock::$retries;
-
-		// Re-use an existing handle or get a new one
-		if(empty($existingHandle)) {
-			$handle = fopen($this->path, 'r');
-		}
-		else {
-			$handle = $existingHandle;
-		}
-
-		do {
-			if($this->isLockFileLocked($this->getLockFile($this->path))) {
-				\OC_Log::write('lock', sprintf('INFO: Read lock has locked lock file %s for %s', $this->getLockFile($this->path), $this->path), \OC_Log::DEBUG);
-				do {
-					usleep(Lock::$retryInterval);
-					$timeout--;
-				} while($this->isLockFileLocked($this->getLockFile($this->path)) && $timeout > 0);
-				\OC_Log::write('lock', sprintf('INFO: Lock file %s has become unlocked for %s', $this->getLockFile($this->path), $this->path), \OC_Log::DEBUG);
-			}
-		} while ((!$lockReturn = flock($handle, LOCK_SH | LOCK_NB, $wouldBlock)) && $timeout > 0);
-		if ($wouldBlock == true || $lockReturn == false || $timeout <= 0) {
-			\OC_Log::write('lock', sprintf('FAIL: Failed to acquire read lock for %s', $this->path), \OC_Log::DEBUG);
-			return false;
-		}
-		$this->handle = $handle;
-		\OC_Log::write('lock', sprintf('PASS: Acquired read lock for %s', $this->path), \OC_Log::DEBUG);
-		return true;
-	}
-
-	protected function obtainWriteLock($existingHandle = null) {
-		\OC_Log::write('lock', sprintf('INFO: Write lock requested for %s', $this->path), \OC_Log::DEBUG);
-
-		// Re-use an existing handle or get a new one
-		if (empty($existingHandle)) {
-			$handle = fopen($this->path, 'c');
-		}
-		else {
-			$handle = $existingHandle;
-		}
-
-		// If the file doesn't exist, but we can create a lock for it
-		if (!file_exists($this->path) && $this->lockLockFile($this->path)) {
-			$lockReturn = flock($handle, LOCK_EX | LOCK_NB, $wouldBlock);
-			if ($lockReturn == false || $wouldBlock == true) {
-				\OC_Log::write('lock', sprintf('FAIL: Write lock failed, unable to exclusively lock new file %s', $this->path), \OC_Log::DEBUG);
-				return false;
-			}
-			$this->handle = $handle;
-			return true;
-		}
-
-
-		// Since this file does exist, wait for locks to release to get an exclusive lock
-		$timeout = Lock::$retries;
-		$haveBlock = false;
-		while ((!$lockReturn = flock($handle, LOCK_EX | LOCK_NB, $wouldBlock)) && $timeout > 0) {
-			// We don't have a lock on the original file, try to get a lock on its lock file
-			if ($haveBlock || $haveBlock = $this->lockLockFile($this->lockFile)) {
-				usleep(Lock::$retryInterval);
-			}
-			else {
-				\OC_Log::write('lock', sprintf('FAIL: Write lock failed, unable to lock original %s or lock file', $this->path), \OC_Log::DEBUG);
-				return false;
-			}
-			$timeout--;
-		}
-		if ($wouldBlock == true || $lockReturn == false) {
-			\OC_Log::write('lock', sprintf('FAIL: Write lock failed due to timeout on %s', $this->path), \OC_Log::DEBUG);
-			return false;
-		}
-		\OC_Log::write('lock', sprintf('PASS: Write lock succeeded on %s', $this->path), \OC_Log::DEBUG);
-
-		return true;
-	}
-
-	/**
-	 * Create a lock file and lock it
-	 * Sets $this->lockFile to the specified lock file, indicating that the lock file is IN USE for this lock instance
-	 * Also sets $this->lockFileHandle to a file handle of the lock file
-	 * @param string $filename The name of the file to lock
-	 * @return bool False if lock can't be acquired, true if it can.
-	 */
-	protected function lockLockFile ( $filename ) {
-		$lockFile = $this->getLockFile($filename);
-		\OC_Log::write('lock', sprintf('INFO: Locking lock file %s for %s', $lockFile, $filename), \OC_Log::DEBUG);
-
-		// If we already manage the lockfile, success
-		if(!empty($this->lockFile)) {
-			\OC_Log::write('lock', sprintf('PASS: Lock file %s was locked by this request for %s', $lockFile, $filename), \OC_Log::DEBUG);
-			return true;
-		}
-
-		// Check if the lockfile exists, and if not, try to create it
-		\OC_Log::write('lock', sprintf('INFO: Does lock file %s already exist?  %s', $lockFile, file_exists($lockFile) ? 'yes' : 'no'), \OC_Log::DEBUG);
-		$handle = fopen($lockFile, 'c');
-		if(!$handle) {
-			\OC_Log::write('lock', sprintf('FAIL: Could not create lock file %s', $lockFile), \OC_Log::DEBUG);
-			return false;
-		}
-
-		// Attempt to acquire lock on lock file
-		$wouldBlock = false;
-		$timeout = self::$retries;
-		// Wait for lock over timeout
-		while((!$lockReturn = flock($handle, LOCK_EX | LOCK_NB, $wouldBlock)) && $timeout > 0) {
-			\OC_Log::write('lock', sprintf('FAIL: Could not acquire lock on lock file %s, %s timeout increments remain.', $lockFile, $timeout), \OC_Log::DEBUG);
-			usleep(self::$retryInterval);
-			$timeout--;
-		}
-		if ($wouldBlock == true || $lockReturn == false) {
-			\OC_Log::write('lock', sprintf('FAIL: Could not acquire lock on lock file %s', $lockFile), \OC_Log::DEBUG);
-			return false;
-		}
-		fwrite($handle, $filename);
-		\OC_Log::write('lock', sprintf('PASS: Wrote filename to lock lock file %s', $lockFile), \OC_Log::DEBUG);
-
-		$this->lockFile = $lockFile;
-		$this->lockFileHandle = $handle;
+	public function __construct($path);
 
-		return true;
-	}
 
 	/**
 	 * Add a lock of a specific type to the stack
@@ -188,50 +39,12 @@ class Lock {
 	 * @param null|resource $existingHandle An existing file handle from an fopen()
 	 * @throws LockNotAcquiredException
 	 */
-	public function addLock($lockType, $existingHandle = null) {
-		if(!isset($this->stack[$lockType])) {
-			switch($lockType) {
-				case Lock::READ:
-					$result = $this->obtainReadLock($existingHandle);
-					break;
-				case Lock::WRITE:
-					$result = $this->obtainWriteLock($existingHandle);
-					break;
-				default:
-					$result = false;
-					break;
-			}
-			if($result) {
-				$this->stack[$lockType] = 0;
-			}
-			else {
-				throw new LockNotAcquiredException($this->path, $lockType);
-			}
-		}
-
-		\OC_Log::write('lock', sprintf('INFO: Incrementing lock type %d count for %s', $lockType, $this->path), \OC_Log::DEBUG);
-		$this->stack[$lockType]++;
-
-	}
+	public function addLock($lockType, $existingHandle = null);
 
 	/**
 	 * Release locks on handles and files
 	 */
-	public function release($lockType) {
-		if(isset($this->stack[$lockType])) {
-			$this->stack[$lockType]--;
-			if($this->stack[$lockType] <= 0) {
-				unset($this->stack[$lockType]);
-			}
-		}
-
-		if(count($this->stack) == 0) {
-			// No more locks needed on this file, release the handle and/or lockfile
-			$this->releaseAll();
-		}
-
-		return true;
-	}
+	public function release($lockType);
 
 
 	/**
@@ -239,72 +52,12 @@ class Lock {
 	 * @param string $filename The filename of the file to create a lock file for
 	 * @return string The filename of the lock file
 	 */
-	public static function getLockFile($filename) {
-		static $locksDir = false;
-		if(!$locksDir) {
-			$dataDir = Config::getSystemValue('datadirectory');
-			$locksDir = $dataDir . '/.locks';
-			if(!file_exists($locksDir)) {
-				mkdir($locksDir);
-			}
-		}
-		$filename = Filesystem::normalizePath($filename);
-		return $locksDir . '/' . sha1($filename) . '.lock';
-	}
-
-	/**
-	 * Determine if a file has an associated and flocked lock file
-	 * @param string $lockFile The filename of the lock file to check
-	 * @return bool True if the lock file is flocked
-	 */
-	protected function isLockFileLocked($lockFile) {
-		if(file_exists($lockFile)) {
-			if($handle = fopen($lockFile, 'c')) {
-				if($lock = flock($handle, LOCK_EX | LOCK_NB)) {
-					// Got lock, not blocking, release and unlink
-					unlink($lockFile);
-					fclose($handle);
-					flock($lock, LOCK_UN);
-					return false;
-				}
-				else {
-					return true;
-				}
-			}
-			else {
-				return true;
-			}
-		}
-		return false;
-	}
+	public static function getLockFile($filename);
 
 	/**
 	 * Release all queued locks on the file
 	 * @return bool
 	 */
-	public function releaseAll() {
-		$this->stack = array();
-		\OC_Log::write('lock', sprintf('INFO: Releasing locks on %s', $this->path), \OC_Log::DEBUG);
-		if (!empty($this->handle) && is_resource($this->handle)) {
-			flock($this->handle, LOCK_UN);
-			\OC_Log::write('lock', sprintf('INFO: Released lock handle %s on %s', $this->handle, $this->path), \OC_Log::DEBUG);
-			$this->handle = null;
-		}
-		if (!empty($this->lockFile) && file_exists($this->lockFile)) {
-			unlink($this->lockFile);
-			\OC_Log::write('lock', sprintf('INFO: Released lock file %s on %s', $this->lockFile, $this->path), \OC_Log::DEBUG);
-			$this->lockFile = null;
-		}
-		\OC_Log::write('lock', sprintf('FREE: Released locks on %s', $this->path), \OC_Log::DEBUG);
-		return true;
-	}
-
-	public function __destruct() {
-		// Only releaseAll if we have locks to release
-		if(!empty($this->handle) || !empty($this->lockFile)) {
-			\OC_Log::write('lock', sprintf('INFO: Destroying locks on %s', $this->path), \OC_Log::DEBUG);
-			$this->releaseAll();
-		}
-	}
+	public function releaseAll();
 
 }
\ No newline at end of file