[Draft] naive attempt to move Linux native code to FFM API

resources/bundles/org.eclipse.core.filesystem/.classpath

@@ -1,7 +1,16 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <classpath>
-	<classpathentry kind="con" path="org.eclipse.jdt.launching.JRE_CONTAINER/org.eclipse.jdt.internal.debug.ui.launcher.StandardVMType/JavaSE-17"/>
+	<classpathentry kind="con" path="org.eclipse.jdt.launching.JRE_CONTAINER/org.eclipse.jdt.internal.debug.ui.launcher.StandardVMType/JavaSE-25">
+		<attributes>
+			<attribute name="module" value="true"/>
+		</attributes>
+	</classpathentry>
 	<classpathentry kind="con" path="org.eclipse.pde.core.requiredPlugins"/>
-	<classpathentry kind="src" path="src"/>
+	<classpathentry kind="src" output="bin" path="src"/>
+	<classpathentry kind="src" output="bin25" path="src25">
+		<attributes>
+			<attribute name="release" value="25"/>
+		</attributes>
+	</classpathentry>
 	<classpathentry kind="output" path="bin"/>
 </classpath>

resources/bundles/org.eclipse.core.filesystem/.gitignore

@@ -0,0 +1 @@
+/bin25/

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

@@ -8,11 +8,14 @@ Require-Bundle: org.eclipse.core.runtime;bundle-version="[3.29.0,4.0.0)"
 Export-Package: org.eclipse.core.filesystem;uses:="org.eclipse.core.runtime",
  org.eclipse.core.filesystem.provider;uses:="org.eclipse.core.filesystem,org.eclipse.core.runtime",
  org.eclipse.core.internal.filesystem;x-internal:=true,
+ org.eclipse.core.internal.filesystem.linux;x-internal:=true,
  org.eclipse.core.internal.filesystem.local;x-internal:=true,
  org.eclipse.core.internal.filesystem.local.unix;x-internal:=true
 Bundle-Vendor: %providerName
 Bundle-RequiredExecutionEnvironment: JavaSE-17
 Bundle-ActivationPolicy: lazy
 Automatic-Module-Name: org.eclipse.core.filesystem
+Require-Capability: osgi.ee;filter:="(&(osgi.ee=JavaSE)(version=17))"
+Multi-Release: true
 Import-Package: com.sun.jna;version="[5.14.0,6.0.0)",
  com.sun.jna.platform.win32;version="[5.14.0,6.0.0)"

resources/bundles/org.eclipse.core.filesystem/META-INF/versions/25/OSGI-INF/MANIFEST.MF

@@ -0,0 +1,2 @@
+Manifest-Version: 1.0
+Require-Capability: osgi.ee;filter:="(&(osgi.ee=JavaSE)(version=25))"

resources/bundles/org.eclipse.core.filesystem/build.properties

@@ -13,6 +13,8 @@
 ###############################################################################
 source.. = src/
 output.. = bin/
+source.META-INF/versions/25/ = src25/
+output.META-INF/versions/25/ = bin25/
 bin.includes = META-INF/,\
                .,\
                plugin.xml,\

resources/bundles/org.eclipse.core.filesystem/src25/org/eclipse/core/internal/filesystem/linux/LinuxFileFlags.java

@@ -0,0 +1,73 @@
+/*******************************************************************************
+ * Copyright (c) 2025 Eclipse contributors and others.
+ *
+ * This program and the accompanying materials
+ * are made available under the terms of the Eclipse Public License 2.0
+ * which accompanies this distribution, and is available at
+ * https://www.eclipse.org/legal/epl-2.0/
+ *
+ * SPDX-License-Identifier: EPL-2.0
+ *
+ * Contributors:
+ *     Eclipse contributors - initial API and implementation
+ *******************************************************************************/
+package org.eclipse.core.internal.filesystem.linux;
+
+/**
+ * Linux-specific file mode flags.
+ *
+ * <p>These are standard POSIX constants as defined in {@code <sys/stat.h>} and are
+ * identical across all Linux architectures. No Mac OS X specific flags
+ * (such as {@code UF_IMMUTABLE} or {@code SF_IMMUTABLE}) are present here since
+ * they are not supported on Linux.</p>
+ *
+ * @since 1.11.500
+ */
+public final class LinuxFileFlags {
+
+	/**
+	 * Maximum number of characters in a file path including the null terminator.
+	 */
+	public static final int PATH_MAX = 4096;
+
+	/** Bitmask for the file type bitfields in {@code st_mode}. */
+	public static final int S_IFMT  = 0xF000;
+
+	/** File type: symbolic link. */
+	public static final int S_IFLNK = 0xA000;
+
+	/** File type: directory. */
+	public static final int S_IFDIR = 0x4000;
+
+	/** Owner has read permission. */
+	public static final int S_IRUSR = 0x0100;
+
+	/** Owner has write permission. */
+	public static final int S_IWUSR = 0x0080;
+
+	/** Owner has execute permission. */
+	public static final int S_IXUSR = 0x0040;
+
+	/** Group has read permission. */
+	public static final int S_IRGRP = 0x0020;
+
+	/** Group has write permission. */
+	public static final int S_IWGRP = 0x0010;
+
+	/** Group has execute permission. */
+	public static final int S_IXGRP = 0x0008;
+
+	/** Others have read permission. */
+	public static final int S_IROTH = 0x0004;
+
+	/** Others have write permission. */
+	public static final int S_IWOTH = 0x0002;
+
+	/** Others have execute permission. */
+	public static final int S_IXOTH = 0x0001;
+
+	private LinuxFileFlags() {
+		// not instantiable
+	}
+
+}

resources/bundles/org.eclipse.core.filesystem/src25/org/eclipse/core/internal/filesystem/linux/LinuxFileHandler.java

@@ -0,0 +1,53 @@
+/*******************************************************************************
+ * Copyright (c) 2025 Eclipse contributors and others.
+ *
+ * This program and the accompanying materials
+ * are made available under the terms of the Eclipse Public License 2.0
+ * which accompanies this distribution, and is available at
+ * https://www.eclipse.org/legal/epl-2.0/
+ *
+ * SPDX-License-Identifier: EPL-2.0
+ *
+ * Contributors:
+ *     Eclipse contributors - initial API and implementation
+ *******************************************************************************/
+package org.eclipse.core.internal.filesystem.linux;
+
+import org.eclipse.core.filesystem.IFileInfo;
+import org.eclipse.core.filesystem.provider.FileInfo;
+import org.eclipse.core.internal.filesystem.local.NativeHandler;
+
+/**
+ * A {@link NativeHandler} for Linux that uses the Java 25 Foreign Function &
+ * Memory (FFM) API instead of JNI to access native file operations.
+ *
+ * <p>This handler delegates to {@link LinuxFileNatives}, which calls
+ * {@code statx(2)}, {@code chmod(2)} and {@code readlink(2)} directly via
+ * FFM downcall handles. No native shared library (.so) is required — the
+ * standard C library (libc) is used directly.</p>
+ *
+ * <p>Mac OS X specific code paths present in the old {@code UnixFileHandler}
+ * (chflags, UF_IMMUTABLE, SF_IMMUTABLE, CoreServices unicode conversion) are
+ * intentionally absent. This handler is exclusively for Linux.</p>
+ *
+ * @since 1.11.500
+ * @see LinuxFileNatives
+ */
+public class LinuxFileHandler extends NativeHandler {
+
+	@Override
+	public int getSupportedAttributes() {
+		return LinuxFileNatives.getSupportedAttributes();
+	}
+
+	@Override
+	public FileInfo fetchFileInfo(String fileName) {
+		return LinuxFileNatives.fetchFileInfo(fileName);
+	}
+
+	@Override
+	public boolean putFileInfo(String fileName, IFileInfo info, int options) {
+		return LinuxFileNatives.putFileInfo(fileName, info, options);
+	}
+
+}