Fixed quota stream's fseek method

- Added missing return statement
- Added missing support for SEEK_END
- Fixes #5524

lib/private/files/stream/quota.php

@@ -66,12 +66,22 @@ class Quota {
 	}
 
 	public function stream_seek($offset, $whence = SEEK_SET) {
-		if ($whence === SEEK_SET) {
+		if ($whence === SEEK_END){
+			// go to the end to find out last position's offset
+			$oldOffset = $this->stream_tell();
+			if (fseek($this->source, 0, $whence) !== 0){
+				return false;
+			}
+			$whence = SEEK_SET;
+			$offset = $this->stream_tell() + $offset;
+			$this->limit += $oldOffset - $offset;
+		}
+		else if ($whence === SEEK_SET) {
 			$this->limit += $this->stream_tell() - $offset;
 		} else {
 			$this->limit -= $offset;
 		}
-		fseek($this->source, $offset, $whence);
+		return !fseek($this->source, $offset, $whence);
 	}
 
 	public function stream_tell() {

tests/lib/files/stream/quota.php

@@ -75,4 +75,76 @@ class Quota extends \PHPUnit_Framework_TestCase {
 		rewind($stream);
 		$this->assertEquals('qwerty', fread($stream, 100));
 	}
+
+	public function testFseekReturnsSuccess() {
+		$stream = $this->getStream('w+', 100);
+		fwrite($stream, '0123456789');
+		$this->assertEquals(0, fseek($stream, 3, SEEK_SET));
+		$this->assertEquals(0, fseek($stream, -1, SEEK_CUR));
+		$this->assertEquals(0, fseek($stream, -4, SEEK_END));
+	}
+
+	public function testWriteAfterSeekEndWithEnoughSpace() {
+		$stream = $this->getStream('w+', 100);
+		fwrite($stream, '0123456789');
+		fseek($stream, -3, SEEK_END);
+		$this->assertEquals(11, fwrite($stream, 'abcdefghijk'));
+		rewind($stream);
+		$this->assertEquals('0123456abcdefghijk', fread($stream, 100));
+	}
+
+	public function testWriteAfterSeekEndWithNotEnoughSpace() {
+		$stream = $this->getStream('w+', 13);
+		fwrite($stream, '0123456789');
+		// seek forward first to potentially week out
+		// potential limit calculation errors
+		fseek($stream, 4, SEEK_SET);
+		// seek to the end
+		fseek($stream, -3, SEEK_END);
+		$this->assertEquals(6, fwrite($stream, 'abcdefghijk'));
+		rewind($stream);
+		$this->assertEquals('0123456abcdef', fread($stream, 100));
+	}
+
+	public function testWriteAfterSeekSetWithEnoughSpace() {
+		$stream = $this->getStream('w+', 100);
+		fwrite($stream, '0123456789');
+		fseek($stream, 7, SEEK_SET);
+		$this->assertEquals(11, fwrite($stream, 'abcdefghijk'));
+		rewind($stream);
+		$this->assertEquals('0123456abcdefghijk', fread($stream, 100));
+	}
+
+	public function testWriteAfterSeekSetWithNotEnoughSpace() {
+		$stream = $this->getStream('w+', 13);
+		fwrite($stream, '0123456789');
+		fseek($stream, 7, SEEK_SET);
+		$this->assertEquals(6, fwrite($stream, 'abcdefghijk'));
+		rewind($stream);
+		$this->assertEquals('0123456abcdef', fread($stream, 100));
+	}
+
+	public function testWriteAfterSeekCurWithEnoughSpace() {
+		$stream = $this->getStream('w+', 100);
+		fwrite($stream, '0123456789');
+		rewind($stream);
+		fseek($stream, 3, SEEK_CUR);
+		fseek($stream, 5, SEEK_CUR);
+		fseek($stream, -1, SEEK_CUR);
+		$this->assertEquals(11, fwrite($stream, 'abcdefghijk'));
+		rewind($stream);
+		$this->assertEquals('0123456abcdefghijk', fread($stream, 100));
+	}
+
+	public function testWriteAfterSeekCurWithNotEnoughSpace() {
+		$stream = $this->getStream('w+', 13);
+		fwrite($stream, '0123456789');
+		rewind($stream);
+		fseek($stream, 3, SEEK_CUR);
+		fseek($stream, 5, SEEK_CUR);
+		fseek($stream, -1, SEEK_CUR);
+		$this->assertEquals(6, fwrite($stream, 'abcdefghijk'));
+		rewind($stream);
+		$this->assertEquals('0123456abcdef', fread($stream, 100));
+	}
 }