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Use counter to prevent race conditions in UvDriver

Fixes #16.
This commit is contained in:
Niklas Keller 2017-06-18 21:03:44 +02:00
parent 75d2a77951
commit f21ff58272

View File

@ -18,6 +18,9 @@ class UvDriver implements Driver {
/** @var string Loop onReadable watcher. */
private $busy;
/** @var int Number of pending operations for disabling / enabling the busy watcher. */
private $pendingOperations = 0;
/**
* @param \Amp\Loop\UvDriver $driver
*/
@ -25,7 +28,8 @@ class UvDriver implements Driver {
$this->driver = $driver;
$this->loop = $driver->getHandle();
// dummy handle to be able to tell the loop that there is work being done and it shouldn't abort if there are no other watchers at a given moment
// dummy handle to be able to tell the loop that there is work being done and it shouldn't abort if there are no
// other watchers at a given moment
$this->busy = $driver->repeat(PHP_INT_MAX, function () { });
$driver->unreference($this->busy);
}
@ -37,14 +41,12 @@ class UvDriver implements Driver {
$flags = $this->parseMode($mode);
$chmod = ($flags & \UV::O_CREAT) ? 0644 : 0;
$this->driver->reference($this->busy);
$deferred = new Deferred;
$openArr = [$mode, $path, $deferred];
\uv_fs_open($this->loop, $path, $flags, $chmod, function ($fh) use ($openArr) {
if ($fh) {
$this->onOpenHandle($fh, $openArr);
} else {
$this->driver->unreference($this->busy);
list(, $path, $deferred) = $openArr;
$deferred->fail(new FilesystemException(
"Failed opening file handle to $path"
@ -52,7 +54,10 @@ class UvDriver implements Driver {
}
});
return $deferred->promise();
$promise = $deferred->promise();
$this->watchOperation($promise);
return $promise;
}
private function parseMode(string $mode): int {
@ -79,7 +84,6 @@ class UvDriver implements Driver {
list($mode) = $openArr;
if ($mode[0] === "w") {
\uv_fs_ftruncate($this->loop, $fh, $length = 0, function ($fh) use ($openArr) {
$this->driver->unreference($this->busy);
if ($fh) {
$this->finalizeHandle($fh, $size = 0, $openArr);
} else {
@ -91,7 +95,6 @@ class UvDriver implements Driver {
});
} else {
\uv_fs_fstat($this->loop, $fh, function ($fh, $stat) use ($openArr) {
$this->driver->unreference($this->busy);
if ($fh) {
StatCache::set($openArr[1], $stat);
$this->finalizeHandle($fh, $stat["size"], $openArr);
@ -119,7 +122,6 @@ class UvDriver implements Driver {
return new Success($stat);
}
$this->driver->reference($this->busy);
$deferred = new Deferred;
\uv_fs_stat($this->loop, $path, function ($fh, $stat) use ($deferred, $path) {
if (empty($fh)) {
@ -127,11 +129,13 @@ class UvDriver implements Driver {
} else {
StatCache::set($path, $stat);
}
$this->driver->unreference($this->busy);
$deferred->resolve($stat);
});
return $deferred->promise();
$promise = $deferred->promise();
$this->watchOperation($promise);
return $promise;
}
/**
@ -258,96 +262,101 @@ class UvDriver implements Driver {
* {@inheritdoc}
*/
public function lstat(string $path): Promise {
$this->driver->reference($this->busy);
$deferred = new Deferred;
\uv_fs_lstat($this->loop, $path, function ($fh, $stat) use ($deferred) {
if (empty($fh)) {
$stat = null;
}
$this->driver->unreference($this->busy);
$deferred->resolve($stat);
});
return $deferred->promise();
$promise = $deferred->promise();
$this->watchOperation($promise);
return $promise;
}
/**
* {@inheritdoc}
*/
public function symlink(string $target, string $link): Promise {
$this->driver->reference($this->busy);
$deferred = new Deferred;
\uv_fs_symlink($this->loop, $target, $link, \UV::S_IRWXU | \UV::S_IRUSR, function ($fh) use ($deferred) {
$this->driver->unreference($this->busy);
$deferred->resolve((bool) $fh);
});
return $deferred->promise();
$promise = $deferred->promise();
$this->watchOperation($promise);
return $promise;
}
/**
* {@inheritdoc}
*/
public function link(string $target, string $link): Promise {
$this->driver->reference($this->busy);
$deferred = new Deferred;
\uv_fs_link($this->loop, $target, $link, \UV::S_IRWXU | \UV::S_IRUSR, function ($fh) use ($deferred) {
$this->driver->unreference($this->busy);
$deferred->resolve((bool) $fh);
});
return $deferred->promise();
$promise = $deferred->promise();
$this->watchOperation($promise);
return $promise;
}
/**
* {@inheritdoc}
*/
public function readlink(string $path): Promise {
$this->driver->reference($this->busy);
$deferred = new Deferred;
\uv_fs_readlink($this->loop, $path, function ($fh) use ($deferred) {
$this->driver->unreference($this->busy);
$deferred->resolve((bool) $fh);
});
return $deferred->promise();
$promise = $deferred->promise();
$this->watchOperation($promise);
return $promise;
}
/**
* {@inheritdoc}
*/
public function rename(string $from, string $to): Promise {
$this->driver->reference($this->busy);
$deferred = new Deferred;
\uv_fs_rename($this->loop, $from, $to, function ($fh) use ($deferred, $from) {
$this->driver->unreference($this->busy);
StatCache::clear($from);
$deferred->resolve((bool) $fh);
});
return $deferred->promise();
$promise = $deferred->promise();
$this->watchOperation($promise);
return $promise;
}
/**
* {@inheritdoc}
*/
public function unlink(string $path): Promise {
$this->driver->reference($this->busy);
$deferred = new Deferred;
\uv_fs_unlink($this->loop, $path, function ($fh) use ($deferred, $path) {
$this->driver->unreference($this->busy);
StatCache::clear($path);
$deferred->resolve((bool) $fh);
});
return $deferred->promise();
$promise = $deferred->promise();
$this->watchOperation($promise);
return $promise;
}
/**
* {@inheritdoc}
*/
public function mkdir(string $path, int $mode = 0644, bool $recursive = false): Promise {
$this->driver->reference($this->busy);
$deferred = new Deferred;
if ($recursive) {
@ -362,7 +371,6 @@ class UvDriver implements Driver {
if (empty($arrayPath)) {
\uv_fs_mkdir($this->loop, $tmpPath, $mode, function ($fh) use ($deferred) {
$this->driver->unreference($this->busy);
$deferred->resolve((bool) $fh);
});
} else {
@ -381,37 +389,38 @@ class UvDriver implements Driver {
$callback();
} else {
\uv_fs_mkdir($this->loop, $path, $mode, function ($fh) use ($deferred) {
$this->driver->unreference($this->busy);
$deferred->resolve((bool) $fh);
});
}
return $deferred->promise();
$promise = $deferred->promise();
$this->watchOperation($promise);
return $promise;
}
/**
* {@inheritdoc}
*/
public function rmdir(string $path): Promise {
$this->driver->reference($this->busy);
$deferred = new Deferred;
\uv_fs_rmdir($this->loop, $path, function ($fh) use ($deferred, $path) {
$this->driver->unreference($this->busy);
StatCache::clear($path);
$deferred->resolve((bool) $fh);
});
return $deferred->promise();
$promise = $deferred->promise();
$this->watchOperation($promise);
return $promise;
}
/**
* {@inheritdoc}
*/
public function scandir(string $path): Promise {
$this->driver->reference($this->busy);
$deferred = new Deferred;
uv_fs_readdir($this->loop, $path, 0, function ($fh, $data) use ($deferred, $path) {
$this->driver->unreference($this->busy);
if (empty($fh)) {
$deferred->fail(new FilesystemException(
"Failed reading contents from {$path}"
@ -421,21 +430,25 @@ class UvDriver implements Driver {
}
});
return $deferred->promise();
$promise = $deferred->promise();
$this->watchOperation($promise);
return $promise;
}
/**
* {@inheritdoc}
*/
public function chmod(string $path, int $mode): Promise {
$this->driver->reference($this->busy);
$deferred = new Deferred;
\uv_fs_chmod($this->loop, $path, $mode, function ($fh) use ($deferred) {
$this->driver->unreference($this->busy);
$deferred->resolve((bool) $fh);
});
return $deferred->promise();
$promise = $deferred->promise();
$this->watchOperation($promise);
return $promise;
}
/**
@ -443,59 +456,60 @@ class UvDriver implements Driver {
*/
public function chown(string $path, int $uid, int $gid): Promise {
// @TODO Return a failure in windows environments
$this->driver->reference($this->busy);
$deferred = new Deferred;
\uv_fs_chown($this->loop, $path, $uid, $gid, function ($fh) use ($deferred) {
$this->driver->unreference($this->busy);
$deferred->resolve((bool) $fh);
});
return $deferred->promise();
$promise = $deferred->promise();
$this->watchOperation($promise);
return $promise;
}
/**
* {@inheritdoc}
*/
public function touch(string $path): Promise {
$this->driver->reference($this->busy);
$atime = $mtime = time();
$deferred = new Deferred;
\uv_fs_utime($this->loop, $path, $mtime, $atime, function () use ($deferred) {
// The uv_fs_utime() callback does not receive any args at this time
$this->driver->unreference($this->busy);
$deferred->resolve(true);
});
return $deferred->promise();
$promise = $deferred->promise();
$this->watchOperation($promise);
return $promise;
}
/**
* {@inheritdoc}
*/
public function get(string $path): Promise {
return new Coroutine($this->doGet($path));
$promise = new Coroutine($this->doGet($path));
$this->watchOperation($promise);
return $promise;
}
private function doGet($path): \Generator {
$this->driver->reference($this->busy);
$promise = $this->doFsOpen($path, $flags = \UV::O_RDONLY, $mode = 0);
if (!$fh = yield $promise) {
$this->driver->unreference($this->busy);
throw new FilesystemException(
"Failed opening file handle: {$path}"
);
}
$deferred = new Deferred;
$stat = (yield $this->doFsStat($fh));
if (empty($stat)) {
$this->driver->unreference($this->busy);
$deferred->fail(new FilesystemException(
"stat operation failed on open file handle"
));
} elseif (!$stat["isfile"]) {
\uv_fs_close($this->loop, $fh, function () use ($deferred) {
$this->driver->unreference($this->busy);
$deferred->fail(new FilesystemException(
"cannot buffer contents: path is not a file"
));
@ -504,20 +518,18 @@ class UvDriver implements Driver {
$buffer = (yield $this->doFsRead($fh, $offset = 0, $stat["size"]));
if ($buffer === false) {
\uv_fs_close($this->loop, $fh, function () use ($deferred) {
$this->driver->unreference($this->busy);
$deferred->fail(new FilesystemException(
"read operation failed on open file handle"
));
});
} else {
\uv_fs_close($this->loop, $fh, function () use ($deferred, $buffer) {
$this->driver->unreference($this->busy);
$deferred->resolve($buffer);
});
}
}
return yield $deferred->promise();
return $deferred->promise();
}
private function doFsOpen($path, $flags, $mode) {
@ -557,16 +569,16 @@ class UvDriver implements Driver {
* {@inheritdoc}
*/
public function put(string $path, string $contents): Promise {
return new Coroutine($this->doPut($path, $contents));
$promise = new Coroutine($this->doPut($path, $contents));
$this->watchOperation($promise);
return $promise;
}
private function doPut($path, $contents): \Generator {
$flags = \UV::O_WRONLY | \UV::O_CREAT;
$mode = \UV::S_IRWXU | \UV::S_IRUSR;
$this->driver->reference($this->busy);
$promise = $this->doFsOpen($path, $flags, $mode);
if (!$fh = yield $promise) {
$this->driver->unreference($this->busy);
throw new FilesystemException(
"Failed opening write file handle"
);
@ -576,7 +588,6 @@ class UvDriver implements Driver {
$len = strlen($contents);
\uv_fs_write($this->loop, $fh, $contents, $offset = 0, function ($fh, $result) use ($deferred, $len) {
\uv_fs_close($this->loop, $fh, function () use ($deferred, $result, $len) {
$this->driver->unreference($this->busy);
if ($result < 0) {
$deferred->fail(new FilesystemException(
\uv_strerror($result)
@ -587,6 +598,22 @@ class UvDriver implements Driver {
});
});
return yield $deferred->promise();
return $deferred->promise();
}
private function watchOperation(Promise $promise) {
$this->pendingOperations++;
if ($this->pendingOperations === 1) {
$this->driver->reference($this->busy);
}
$promise->onResolve(function () {
$this->pendingOperations--;
if ($this->pendingOperations === 0) {
$this->driver->unreference($this->busy);
}
});
}
}