Implement Open/Close Zip File

resources/bundles/org.eclipse.core.filesystem/META-INF/MANIFEST.MF

@@ -2,7 +2,7 @@ Manifest-Version: 1.0
 Bundle-ManifestVersion: 2
 Bundle-Name: %pluginName
 Bundle-SymbolicName: org.eclipse.core.filesystem; singleton:=true
-Bundle-Version: 1.10.400.qualifier
+Bundle-Version: 1.11.0.qualifier
 Bundle-Localization: plugin
 Require-Bundle: org.eclipse.equinox.common;bundle-version="[3.18.0,4.0.0)",
  org.eclipse.equinox.registry;bundle-version="[3.2.0,4.0.0)",

resources/bundles/org.eclipse.core.filesystem/plugin.xml

@@ -16,4 +16,11 @@
          <run class="org.eclipse.core.internal.filesystem.NullFileSystem"/>
       </filesystem>
    </extension>
+   <extension
+         id="org.eclipse.core.filesystem.zip"
+         point="org.eclipse.core.filesystem.filesystems">
+      <filesystem scheme="zip">
+         <run class="org.eclipse.core.internal.filesystem.zip.ZipFileSystem"/>
+      </filesystem>
+   </extension>
 </plugin>

resources/bundles/org.eclipse.core.filesystem/src/org/eclipse/core/filesystem/ZipFileUtil.java

@@ -0,0 +1,73 @@
+package org.eclipse.core.filesystem;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.net.URI;
+import java.nio.ByteBuffer;
+import java.nio.ByteOrder;
+import java.util.HashSet;
+import java.util.Set;
+import org.eclipse.core.internal.filesystem.zip.ZipFileStore;
+import org.eclipse.core.runtime.CoreException;
+
+/**
+ * Utility class to determine if a file is an archive based on file header information.
+ * This class checks for known file signatures to identify if a given file is a ZIP archive
+ * or a format based on ZIP, such as EPUB, JAR, ODF, and OOXML.
+ *
+ * @since 1.11
+ */
+public class ZipFileUtil {
+
+    private static final Set<Integer> ARCHIVE_FILE_SIGNATURES = new HashSet<>();
+
+    static {
+		// Initializes known archive file signatures from Wikipedia's list of file signatures
+		// (https://en.wikipedia.org/wiki/List_of_file_signatures)
+        ARCHIVE_FILE_SIGNATURES.add(0x504B0304); // Standard ZIP file
+		ARCHIVE_FILE_SIGNATURES.add(0x504B0506); // Empty archive
+		ARCHIVE_FILE_SIGNATURES.add(0x504B0708); // Spanned archive
+    }
+
+	/**
+	 * Determines if the given {@link IFileStore} represents an open ZIP file.
+	 * This can be used to check if operations on a ZIP file should be allowed or handled differently.
+	 *
+	 * @param store The file store to check.
+	 * @return true if the store is an instance of {@link ZipFileStore}, false otherwise.
+	 */
+	public static boolean isInsideOpenZipFile(IFileStore store) {
+		return store instanceof ZipFileStore;
+	}
+
+	public static boolean isInsideOpenZipFile(URI locationURI) {
+		IFileStore store;
+		try {
+			store = EFS.getStore(locationURI);
+		} catch (CoreException e) {
+			return false;
+		}
+		return isInsideOpenZipFile(store);
+	}
+
+	/**
+	 * Checks if the provided {@link InputStream} represents a ZIP archive
+	 * by reading its first four bytes and comparing them against known ZIP file signatures.
+	 * This method throws {@link IOException} if the file signature does not match any known ZIP archive signatures.
+	 *
+	 * @param fis The {@link InputStream} of the file to check.
+	 * @throws IOException If the file signature does not match known ZIP archive signatures
+	 *                     or an I/O error occurs during reading from the stream.
+	 */
+	public static void checkFileForZipHeader(InputStream fis) throws IOException {
+		byte[] bytes = new byte[4];
+		if (fis.read(bytes) == bytes.length) {
+			ByteBuffer buffer = ByteBuffer.wrap(bytes).order(ByteOrder.BIG_ENDIAN);
+			int header = buffer.getInt();
+
+			if (!ARCHIVE_FILE_SIGNATURES.contains(header)) {
+				throw new IOException("Invalid archive file signature."); //$NON-NLS-1$
+			}
+		}
+	}
+}