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filebackend: add idiom constant to FileBackend for null results

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Change-Id: I65f043e87d82192c13d3627fb45ef222f0290bf8
This commit is contained in:
Aaron Schulz 2019-08-29 01:14:24 -07:00
parent d7fbea76fd
commit 5719815f3b
5 changed files with 56 additions and 34 deletions
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8
includes/libs/filebackend/FSFileBackend.php
View file

@ -593,7 +593,7 @@ class FSFileBackend extends FileBackendStore {
} elseif ( !$hadError ) {
return false; // file does not exist
} else {
return null; // failure
return self::UNKNOWN; // failure
}
}
@ -610,7 +610,7 @@ class FSFileBackend extends FileBackendStore {
$exists = is_dir( $dir );
$hadError = $this->untrapWarnings();
return $hadError ? null : $exists;
return $hadError ? self::UNKNOWN : $exists;
}
/**
@ -632,7 +632,7 @@ class FSFileBackend extends FileBackendStore {
} elseif ( !is_readable( $dir ) ) {
$this->logger->warning( __METHOD__ . "() given directory is unreadable: '$dir'\n" );
return null; // bad permissions?
return self::UNKNOWN; // bad permissions?
}
return new FSFileBackendDirList( $dir, $params );
@ -657,7 +657,7 @@ class FSFileBackend extends FileBackendStore {
} elseif ( !is_readable( $dir ) ) {
$this->logger->warning( __METHOD__ . "() given directory is unreadable: '$dir'\n" );
return null; // bad permissions?
return self::UNKNOWN; // bad permissions?
}
return new FSFileBackendFileList( $dir, $params );

56
includes/libs/filebackend/FileBackend.php
View file

@ -131,6 +131,9 @@ abstract class FileBackend implements LoggerAwareInterface {
const ATTR_METADATA = 2; // files can be stored with metadata key/values
const ATTR_UNICODE_PATHS = 4; // files can have Unicode paths (not just ASCII)
/** @var null Idiom for "could not determine due to I/O errors" */
const UNKNOWN = null;
/**
* Create a new backend instance from configuration.
* This should only be called from within FileBackendGroup.
@ -209,7 +212,8 @@ abstract class FileBackend implements LoggerAwareInterface {
}
/**
* Get the unique backend name.
* Get the unique backend name
*
* We may have multiple different backends of the same type.
* For example, we can have two Swift backends using different proxies.
*
@ -231,6 +235,7 @@ abstract class FileBackend implements LoggerAwareInterface {
/**
* Alias to getDomainId()
*
* @return string
* @since 1.20
* @deprecated Since 1.34 Use getDomainId()
@ -1164,21 +1169,34 @@ abstract class FileBackend implements LoggerAwareInterface {
abstract public function getFileHttpUrl( array $params );
/**
* Check if a directory exists at a given storage path.
* Backends using key/value stores will check if the path is a
* virtual directory, meaning there are files under the given directory.
* Check if a directory exists at a given storage path
*
* For backends using key/value stores, a directory is said to exist whenever
* there exist any files with paths using the given directory path as a prefix
* followed by a forward slash. For example, if there is a file called
* "mwstore://backend/container/dir/path.svg" then directories are said to exist
* at "mwstore://backend/container" and "mwstore://backend/container/dir". These
* can be thought of as "virtual" directories.
*
* Backends that directly use a filesystem layer might enumerate empty directories.
* The clean() method should always be used when files are deleted or moved if this
* is a concern. This is a trade-off to avoid write amplication/contention on file
* changes or read amplification when calling this method.
*
* Storage backends with eventual consistency might return stale data.
*
* @see FileBackend::clean()
*
* @param array $params Parameters include:
* - dir : storage directory
* @return bool|null Returns null on failure
* @return bool|null Whether a directory exists or null on failure
* @since 1.20
*/
abstract public function directoryExists( array $params );
/**
* Get an iterator to list *all* directories under a storage directory.
* Get an iterator to list *all* directories under a storage directory
*
* If the directory is of the form "mwstore://backend/container",
* then all directories in the container will be listed.
* If the directory is of form "mwstore://backend/container/dir",
@ -1189,10 +1207,12 @@ abstract class FileBackend implements LoggerAwareInterface {
*
* Failures during iteration can result in FileBackendError exceptions (since 1.22).
*
* @see FileBackend::directoryExists()
*
* @param array $params Parameters include:
* - dir : storage directory
* - topOnly : only return direct child dirs of the directory
* @return Traversable|array|null Returns null on failure
* @return Traversable|array|null Directory list enumerator null on failure
* @since 1.20
*/
abstract public function getDirectoryList( array $params );
@ -1205,9 +1225,11 @@ abstract class FileBackend implements LoggerAwareInterface {
*
* Failures during iteration can result in FileBackendError exceptions (since 1.22).
*
* @see FileBackend::directoryExists()
*
* @param array $params Parameters include:
* - dir : storage directory
* @return Traversable|array|null Returns null on failure
* @return Traversable|array|null Directory list enumerator or null on failure
* @since 1.20
*/
final public function getTopDirectoryList( array $params ) {
@ -1215,12 +1237,12 @@ abstract class FileBackend implements LoggerAwareInterface {
}
/**
* Get an iterator to list *all* stored files under a storage directory.
* If the directory is of the form "mwstore://backend/container",
* then all files in the container will be listed.
* If the directory is of form "mwstore://backend/container/dir",
* then all files under that directory will be listed.
* Results will be storage paths relative to the given directory.
* Get an iterator to list *all* stored files under a storage directory
*
* If the directory is of the form "mwstore://backend/container", then all
* files in the container will be listed. If the directory is of form
* "mwstore://backend/container/dir", then all files under that directory will
* be listed. Results will be storage paths relative to the given directory.
*
* Storage backends with eventual consistency might return stale data.
*
@ -1230,7 +1252,7 @@ abstract class FileBackend implements LoggerAwareInterface {
* - dir : storage directory
* - topOnly : only return direct child files of the directory (since 1.20)
* - adviseStat : set to true if stat requests will be made on the files (since 1.22)
* @return Traversable|array|null Returns null on failure
* @return Traversable|array|null File list enumerator or null on failure
*/
abstract public function getFileList( array $params );
@ -1245,7 +1267,7 @@ abstract class FileBackend implements LoggerAwareInterface {
* @param array $params Parameters include:
* - dir : storage directory
* - adviseStat : set to true if stat requests will be made on the files (since 1.22)
* @return Traversable|array|null Returns null on failure
* @return Traversable|array|null File list enumerator or null on failure
* @since 1.20
*/
final public function getTopFileList( array $params ) {
@ -1283,7 +1305,7 @@ abstract class FileBackend implements LoggerAwareInterface {
* @param array $params Parameters include:
* - srcs : list of source storage paths
* - latest : use the latest available data
* @return bool All requests proceeded without I/O errors (since 1.24)
* @return bool Whether all requests proceeded without I/O errors (since 1.24)
* @since 1.23
*/
abstract public function preloadFileStat( array $params );

10
includes/libs/filebackend/FileBackendStore.php
View file

@ -604,7 +604,7 @@ abstract class FileBackendStore extends FileBackend {
$ps = $this->scopedProfileSection( __METHOD__ . "-{$this->name}" );
$stat = $this->getFileStat( $params );
return ( $stat === null ) ? null : (bool)$stat; // null => failure
return ( $stat === self::UNKNOWN ) ? self::UNKNOWN : (bool)$stat;
}
final public function getFileTimestamp( array $params ) {
@ -637,7 +637,7 @@ abstract class FileBackendStore extends FileBackend {
// cache entries from mass object listings that do not include the SHA-1. In that
// case, loading the persistent stat cache will likely yield the SHA-1.
if (
$stat === null ||
$stat === self::UNKNOWN ||
( $requireSHA1 && is_array( $stat ) && !isset( $stat['sha1'] ) )
) {
$this->primeFileCache( [ $path ] ); // check persistent cache
@ -936,7 +936,7 @@ abstract class FileBackendStore extends FileBackend {
$res = true;
break; // found one!
} elseif ( $exists === null ) { // error?
$res = null; // if we don't find anything, it is indeterminate
$res = self::UNKNOWN; // if we don't find anything, it is indeterminate
}
}
@ -957,7 +957,7 @@ abstract class FileBackendStore extends FileBackend {
final public function getDirectoryList( array $params ) {
list( $fullCont, $dir, $shard ) = $this->resolveStoragePath( $params['dir'] );
if ( $dir === null ) { // invalid storage path
return null;
return self::UNKNOWN;
}
if ( $shard !== null ) {
// File listing is confined to a single container/shard
@ -987,7 +987,7 @@ abstract class FileBackendStore extends FileBackend {
final public function getFileList( array $params ) {
list( $fullCont, $dir, $shard ) = $this->resolveStoragePath( $params['dir'] );
if ( $dir === null ) { // invalid storage path
return null;
return self::UNKNOWN;
}
if ( $shard !== null ) {
// File listing is confined to a single container/shard

2
includes/libs/filebackend/MemoryFileBackend.php
View file

@ -148,7 +148,7 @@ class MemoryFileBackend extends FileBackendStore {
protected function doGetFileStat( array $params ) {
$src = $this->resolveHashKey( $params['src'] );
if ( $src === null ) {
return null;
return false; // invalid path
}
if ( isset( $this->files[$src] ) ) {

14
includes/libs/filebackend/SwiftFileBackend.php
View file

@ -593,7 +593,7 @@ class SwiftFileBackend extends FileBackendStore {
$stat = $this->getContainerStat( $fullCont );
if ( is_array( $stat ) ) {
return $status; // already there
} elseif ( $stat === null ) {
} elseif ( $stat === self::UNKNOWN ) {
$status->fatal( 'backend-fail-internal', $this->name );
$this->logger->error( __METHOD__ . ': cannot get container stat' );
@ -832,7 +832,7 @@ class SwiftFileBackend extends FileBackendStore {
return ( count( $status->value ) ) > 0;
}
return null; // error
return self::UNKNOWN; // error
}
/**
@ -1401,7 +1401,7 @@ class SwiftFileBackend extends FileBackendStore {
if ( !$this->containerStatCache->hasField( $container, 'stat' ) ) {
$auth = $this->getAuthentication();
if ( !$auth ) {
return null;
return self::UNKNOWN;
}
list( $rcode, $rdesc, $rhdrs, $rbody, $rerr ) = $this->http->run( [
@ -1427,7 +1427,7 @@ class SwiftFileBackend extends FileBackendStore {
$this->onError( null, __METHOD__,
[ 'cont' => $container ], $rerr, $rcode, $rdesc );
return null;
return self::UNKNOWN;
}
}
@ -1599,7 +1599,7 @@ class SwiftFileBackend extends FileBackendStore {
$stats[$path] = false;
continue; // invalid storage path
} elseif ( !$auth ) {
$stats[$path] = null;
$stats[$path] = self::UNKNOWN;
continue;
}
@ -1609,7 +1609,7 @@ class SwiftFileBackend extends FileBackendStore {
$stats[$path] = false;
continue; // ok, nothing to do
} elseif ( !is_array( $cstat ) ) {
$stats[$path] = null;
$stats[$path] = self::UNKNOWN;
continue;
}
@ -1642,7 +1642,7 @@ class SwiftFileBackend extends FileBackendStore {
} elseif ( $rcode === 404 ) {
$stat = false;
} else {
$stat = null;
$stat = self::UNKNOWN;
$this->onError( null, __METHOD__, $params, $rerr, $rcode, $rdesc );
}
$stats[$path] = $stat;