From 2e0e6a00133c17a4d403c8ae403365ab71db0d11 Mon Sep 17 00:00:00 2001
From: Aaron Schulz <aschulz@wikimedia.org>
Date: Tue, 20 Nov 2012 20:58:47 -0800
Subject: [PATCH] [FileBackend] Added back ability to delete file HTTP headers.

* This partially reverts b80bd6159bdf946c1d4fa1e143fea221937d848a.
* Clarified 'headers' parameter documentation a bit.
* Added the "describe" function wrappers that the other ops have.

Change-Id: I7142fd4d973f5f3407d244a4cae793934083bc26
---
 includes/filebackend/FileBackend.php          | 35 +++++++++++++++++++
 includes/filebackend/FileBackendStore.php     |  3 +-
 .../includes/filebackend/FileBackendTest.php  |  2 +-
 3 files changed, 37 insertions(+), 3 deletions(-)

diff --git a/includes/filebackend/FileBackend.php b/includes/filebackend/FileBackend.php
index ef49fe5442..6ea042c84b 100644
--- a/includes/filebackend/FileBackend.php
+++ b/includes/filebackend/FileBackend.php
@@ -267,6 +267,9 @@ abstract class FileBackend {
 	 *   - headers             : If supplied, the backend will return these headers when
 	 *                           GETs/HEADs of the destination file are made. Header values
 	 *                           should be smaller than 256 bytes, often options or numbers.
+	 *                           Existing headers will remain, but these will replace any
+	 *                           conflicting previous headers, and headers will be removed
+	 *                           if they are set to an empty string.
 	 *                           Backends that don't support metadata ignore this. (since 1.21)
 	 *
 	 * $opts is an associative of boolean flags, including:
@@ -407,6 +410,21 @@ abstract class FileBackend {
 		return $this->doOperation( array( 'op' => 'delete' ) + $params, $opts );
 	}
 
+	/**
+	 * Performs a single describe operation.
+	 * This sets $params['op'] to 'describe' and passes it to doOperation().
+	 *
+	 * @see FileBackend::doOperation()
+	 *
+	 * @param $params Array Operation parameters
+	 * @param $opts Array Operation options
+	 * @return Status
+	 * @since 1.21
+	 */
+	final public function describe( array $params, array $opts = array() ) {
+		return $this->doOperation( array( 'op' => 'describe' ) + $params, $opts );
+	}
+
 	/**
 	 * Perform a set of independent file operations on some files.
 	 *
@@ -503,6 +521,9 @@ abstract class FileBackend {
 	 *   - headers             : If supplied, the backend will return these headers when
 	 *                           GETs/HEADs of the destination file are made. Header values
 	 *                           should be smaller than 256 bytes, often options or numbers.
+	 *                           Existing headers will remain, but these will replace any
+	 *                           conflicting previous headers, and headers will be removed
+	 *                           if they are set to an empty string.
 	 *                           Backends that don't support metadata ignore this. (since 1.21)
 	 *
 	 * $opts is an associative of boolean flags, including:
@@ -619,6 +640,20 @@ abstract class FileBackend {
 		return $this->doQuickOperation( array( 'op' => 'delete' ) + $params );
 	}
 
+	/**
+	 * Performs a single quick describe operation.
+	 * This sets $params['op'] to 'describe' and passes it to doQuickOperation().
+	 *
+	 * @see FileBackend::doQuickOperation()
+	 *
+	 * @param $params Array Operation parameters
+	 * @return Status
+	 * @since 1.21
+	 */
+	final public function quickDescribe( array $params ) {
+		return $this->doQuickOperation( array( 'op' => 'describe' ) + $params );
+	}
+
 	/**
 	 * Concatenate a list of storage files into a single file system file.
 	 * The target path should refer to a file that is already locked or
diff --git a/includes/filebackend/FileBackendStore.php b/includes/filebackend/FileBackendStore.php
index 9bbcc0a375..475ac7decb 100644
--- a/includes/filebackend/FileBackendStore.php
+++ b/includes/filebackend/FileBackendStore.php
@@ -1269,8 +1269,7 @@ abstract class FileBackendStore extends FileBackend {
 					trigger_error( "Header '$name: $value' is too long." );
 					unset( $op['headers'][$name] );
 				} elseif ( !strlen( $value ) ) {
-					trigger_error( "Header value for '$name' is empty." );
-					unset( $op['headers'][$name] ); // ignore
+					$op['headers'][$name] = ''; // null/false => ""
 				}
 			}
 		}
diff --git a/tests/phpunit/includes/filebackend/FileBackendTest.php b/tests/phpunit/includes/filebackend/FileBackendTest.php
index 5369112964..7beb4feeab 100644
--- a/tests/phpunit/includes/filebackend/FileBackendTest.php
+++ b/tests/phpunit/includes/filebackend/FileBackendTest.php
@@ -635,7 +635,7 @@ class FileBackendTest extends MediaWikiTestCase {
 		$source = self::baseStorePath() . '/unittest-cont1/e/myfacefile.txt';
 
 		$op = array( 'op' => 'describe', 'src' => $source,
-			'headers' => array( 'X-Content-Length' => '91.3' ),
+			'headers' => array( 'X-Content-Length' => '91.3', 'Content-Old-Header' => '' ),
 			'disposition' => 'inline' );
 		$cases[] = array(
 			$op, // operation
-- 
2.20.1