src/testcases/org/apache/poi/poifs/filesystem/TestEmptyDocument.java

/* ====================================================================
   Licensed to the Apache Software Foundation (ASF) under one or more
   contributor license agreements.  See the NOTICE file distributed with
   this work for additional information regarding copyright ownership.
   The ASF licenses this file to You under the Apache License, Version 2.0
   (the "License"); you may not use this file except in compliance with
   the License.  You may obtain a copy of the License at

       http://www.apache.org/licenses/LICENSE-2.0

   Unless required by applicable law or agreed to in writing, software
   distributed under the License is distributed on an "AS IS" BASIS,
   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   See the License for the specific language governing permissions and
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package org.apache.poi.poifs.filesystem;

import static org.junit.jupiter.api.Assertions.assertArrayEquals;
import static org.junit.jupiter.api.Assertions.assertDoesNotThrow;
import static org.junit.jupiter.api.Assertions.assertEquals;

import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.util.stream.Stream;

import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;
import org.apache.poi.util.IOUtils;
import org.junit.jupiter.api.Test;
import org.junit.jupiter.params.ParameterizedTest;
import org.junit.jupiter.params.provider.Arguments;
import org.junit.jupiter.params.provider.MethodSource;

final class TestEmptyDocument {
    private static final Logger LOG = LogManager.getLogger(TestEmptyDocument.class);

	private interface EmptyDoc {
    	void handle(DirectoryEntry dir) throws IOException;
	}

    public static Stream<Arguments> emptySupplier() {
    	return Stream.of(
    		Arguments.of("SingleEmptyDocument", (EmptyDoc)TestEmptyDocument::SingleEmptyDocument),
			Arguments.of("SingleEmptyDocumentEvent", (EmptyDoc)TestEmptyDocument::SingleEmptyDocumentEvent),
			Arguments.of("EmptyDocumentWithFriend", (EmptyDoc)TestEmptyDocument::EmptyDocumentWithFriend),
			Arguments.of("EmptyDocumentEventWithFriend", (EmptyDoc)TestEmptyDocument::EmptyDocumentEventWithFriend)
		);
	}

	private static void SingleEmptyDocument(DirectoryEntry dir) throws IOException {
		dir.createDocument("Foo", new ByteArrayInputStream(new byte[]{}));
	}

	private static void SingleEmptyDocumentEvent(DirectoryEntry dir) throws IOException {
		dir.createDocument("Foo", 0, event -> LOG.atWarn().log("written"));
	}

	private static void EmptyDocumentWithFriend(DirectoryEntry dir) throws IOException {
		dir.createDocument("Bar", new ByteArrayInputStream(new byte[]{0}));
		dir.createDocument("Foo", new ByteArrayInputStream(new byte[]{}));
	}

	private static void EmptyDocumentEventWithFriend(DirectoryEntry dir) throws IOException {
		dir.createDocument("Bar", 1, event -> {
			try {
				event.getStream().write(0);
			} catch (IOException exception) {
				throw new RuntimeException("exception on write: " + exception);
			}
		});
		dir.createDocument("Foo", 0, event -> {});
	}


	@ParameterizedTest(name = "{index} {0}")
	@MethodSource("emptySupplier")
	void testFoo(String testName, EmptyDoc emptyDoc) throws IOException {
		try (POIFSFileSystem fs = new POIFSFileSystem()) {
			DirectoryEntry dir = fs.getRoot();
			emptyDoc.handle(dir);

			ByteArrayOutputStream out = new ByteArrayOutputStream();
			fs.writeFilesystem(out);
			assertDoesNotThrow(() -> new POIFSFileSystem(new ByteArrayInputStream(out.toByteArray())));
		}
	}

    @Test
	void testEmptyDocumentBug11744() throws Exception {
		byte[] testData = { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 };

		ByteArrayOutputStream out = new ByteArrayOutputStream();
		try (POIFSFileSystem fs = new POIFSFileSystem()) {
			fs.createDocument(new ByteArrayInputStream(new byte[0]), "Empty");
			fs.createDocument(new ByteArrayInputStream(testData), "NotEmpty");
			fs.writeFilesystem(out);
		}

		// This line caused the error.
		try (POIFSFileSystem fs = new POIFSFileSystem(new ByteArrayInputStream(out.toByteArray()))) {
			DocumentEntry entry = (DocumentEntry) fs.getRoot().getEntry("Empty");
			assertEquals(0, entry.getSize(), "Expected zero size");
			byte[] actualReadbackData;
			actualReadbackData = IOUtils.toByteArray(new DocumentInputStream(entry));
			assertEquals(0, actualReadbackData.length, "Expected zero read from stream");

			entry = (DocumentEntry) fs.getRoot().getEntry("NotEmpty");
			actualReadbackData = IOUtils.toByteArray(new DocumentInputStream(entry));
			assertEquals(testData.length, entry.getSize(), "Expected size was wrong");
			assertArrayEquals(testData, actualReadbackData, "Expected same data read from stream");
		}
	}
}