use exceptions for error signaling in writeStream

this remove the ambiguity when writing zero length files

Signed-off-by: Robin Appelman <robin@icewind.nl>

Author: icewind1991

lib/private/Files/Storage/Common.php

@@ -53,6 +53,7 @@
 use OC\Files\Storage\Wrapper\Wrapper;
 use OCP\Files\EmptyFileNameException;
 use OCP\Files\FileNameTooLongException;
+use OCP\Files\GenericFileException;
 use OCP\Files\InvalidCharacterInPathException;
 use OCP\Files\InvalidDirectoryException;
 use OCP\Files\InvalidPathException;
@@ -620,10 +621,14 @@ public function copyFromStorage(IStorage $sourceStorage, $sourceInternalPath, $t
 			}
 		} else {
 			$source = $sourceStorage->fopen($sourceInternalPath, 'r');
+			$result = false;
 			if ($source) {
-				$result = $this->writeStream($targetInternalPath, $source) > 0;
-			} else {
-				$result = false;
+				try {
+					$this->writeStream($targetInternalPath, $source);
+					$result = true;
+				} catch (\Exception $e) {
+					\OC::$server->getLogger()->logException($e, ['level' => ILogger::WARN, 'message' => 'Failed to copy stream to storage']);
+				}
 			}
 
 			if ($result and $preserveMtime) {
@@ -855,10 +860,13 @@ public function needsPartFile() {
 	public function writeStream(string $path, $stream, int $size = null): int {
 		$target = $this->fopen($path, 'w');
 		if (!$target) {
-			return 0;
+			throw new GenericFileException("Failed to open $path for writing");
 		}
 		try {
 			[$count, $result] = \OC_Helper::streamCopy($stream, $target);
+			if (!$result) {
+				throw new GenericFileException("Failed to copy stream");
+			}
 		} finally {
 			fclose($target);
 			fclose($stream);

lib/private/Files/Storage/Local.php

@@ -44,6 +44,7 @@
 use OC\Files\Storage\Wrapper\Jail;
 use OCP\Constants;
 use OCP\Files\ForbiddenException;
+use OCP\Files\GenericFileException;
 use OCP\Files\Storage\IStorage;
 use OCP\ILogger;
 
@@ -553,6 +554,11 @@ public function moveFromStorage(IStorage $sourceStorage, $sourceInternalPath, $t
 	}
 
 	public function writeStream(string $path, $stream, int $size = null): int {
-		return (int)file_put_contents($this->getSourcePath($path), $stream);
+		$result = file_put_contents($this->getSourcePath($path), $stream);
+		if ($result === false) {
+			throw new GenericFileException("Failed write steam to $path");
+		} else {
+			return $result;
+		}
 	}
 }