filebackend: Added supported for retrieving file metadata/headers

* This can be useful for carrying over metadata when copying files around
* Also fixed a bug in sanitizeHdrs() for Swift (broken content-disposition)

Change-Id: I4534e9acac2b306086797b3677f85c05b98e39fc

1 files changed, 45 insertions, 0 deletions

diff --git a/includes/filebackend/FileBackend.php b/includes/filebackend/FileBackend.php
index bb21f1b5e492..f5d63b9df78e 100644
--- a/includes/filebackend/FileBackend.php
+++ b/includes/filebackend/FileBackend.php
@@ -104,6 +104,10 @@ abstract class FileBackend {
 	/** @var FileJournal */
 	protected $fileJournal;
 
+	/** Flags for supported features */
+	const ATTR_HEADERS  = 1;
+	const ATTR_METADATA = 2;
+
 	/**
 	 * Create a new backend instance from configuration.
 	 * This should only be called from within FileBackendGroup.
@@ -201,6 +205,27 @@ abstract class FileBackend {
 	}
 
 	/**
+	 * Get the a bitfield of extra features supported by the backend medium
+	 *
+	 * @return integer Bitfield of FileBackend::ATTR_* flags
+	 * @since 1.23
+	 */
+	public function getFeatures() {
+		return 0;
+	}
+
+	/**
+	 * Check if the backend medium supports a field of extra features
+	 *
+	 * @return integer Bitfield of FileBackend::ATTR_* flags
+	 * @return bool
+	 * @since 1.23
+	 */
+	final public function hasFeatures( $bitfield ) {
+		return ( $this->getFeatures() & $bitfield ) === $bitfield;
+	}
+
+	/**
 	 * This is the main entry point into the backend for write operations.
 	 * Callers supply an ordered list of operations to perform as a transaction.
 	 * Files will be locked, the stat cache cleared, and then the operations attempted.
@@ -902,6 +927,26 @@ abstract class FileBackend {
 	abstract public function getFileContentsMulti( array $params );
 
 	/**
+	 * Get metadata about a file at a storage path in the backend.
+	 * If the file does not exist, then this returns false.
+	 * Otherwise, the result is an associative array that includes:
+	 *   - headers  : map of HTTP headers used for GET/HEAD requests (name => value)
+	 *   - metadata : map of file metadata (name => value)
+	 * Metadata keys and headers names will be returned in all lower-case.
+	 * Additional values may be included for internal use only.
+	 *
+	 * Use FileBackend::hasFeatures() to check how well this is supported.
+	 *
+	 * @param array $params
+	 * $params include:
+	 *   - src    : source storage path
+	 *   - latest : use the latest available data
+	 * @return Array|bool Returns false on failure
+	 * @since 1.23
+	 */
+	abstract public function getFileXAttributes( array $params );
+
+	/**
 	 * Get the size (bytes) of a file at a storage path in the backend.
 	 *
 	 * @param array $params Parameters include: