8293122: (fs) Use file cloning in macOS version of Files::copy method

Reviewed-by: alanb

Author: Brian Burkhalter

src/java.base/macosx/classes/sun/nio/fs/BsdFileSystem.java

@@ -33,8 +33,13 @@
 import java.util.Collections;
 import java.util.HashSet;
 import java.util.Set;
+import sun.nio.ch.IOStatus;
 import sun.security.action.GetPropertyAction;
 
+import static sun.nio.fs.UnixConstants.*;
+import static sun.nio.fs.UnixNativeDispatcher.chown;
+import static sun.nio.fs.UnixNativeDispatcher.unlink;
+
 /**
  * Bsd implementation of FileSystem
  */
@@ -71,13 +76,84 @@ public Set<String> supportedFileAttributeViews() {
         return SupportedFileFileAttributeViewsHolder.supportedFileAttributeViews;
     }
 
+    /**
+     * Clones the file whose path name is {@code src} to that whose path
+     * name is {@code dst} using the {@code clonefile} system call.
+     *
+     * @param src the path of the source file
+     * @param dst the path of the destination file (clone)
+     * @param followLinks whether to follow links
+     *
+     * @return 0 on success, or IOStatus.UNSUPPORTED_CASE if the call
+     *         does not work with the given parameters
+     */
+    private int clone(UnixPath src, UnixPath dst, boolean followLinks)
+        throws IOException
+    {
+        int flags = followLinks ? 0 : CLONE_NOFOLLOW;
+        try {
+            BsdNativeDispatcher.clonefile(src, dst, flags);
+        } catch (UnixException x) {
+            switch (x.errno()) {
+                case ENOTSUP: // cloning not supported by filesystem
+                case EXDEV:   // src and dst on different filesystems
+                case ENOTDIR: // problematic path parameter(s)
+                    return IOStatus.UNSUPPORTED_CASE;
+                default:
+                    x.rethrowAsIOException(src, dst);
+                    return IOStatus.THROWN;
+            }
+        }
+
+        return 0;
+    }
+
     @Override
     protected int directCopy(int dst, int src, long addressToPollForCancel)
         throws UnixException
     {
         return directCopy0(dst, src, addressToPollForCancel);
     }
 
+    @Override
+    protected void copyFile(UnixPath source,
+                            UnixFileAttributes attrs,
+                            UnixPath target,
+                            Flags flags,
+                            long addressToPollForCancel)
+        throws IOException
+    {
+        // Attempt to clone the source unless cancellation is not possible,
+        // or attributes are not to be copied
+        if (addressToPollForCancel == 0 && flags.copyPosixAttributes) {
+            try {
+                int res = clone(source, target, flags.followLinks);
+
+                if (res == 0) {
+                    // copy owner (not done by clonefile)
+                    try {
+                        chown(target, attrs.uid(), attrs.gid());
+                    } catch (UnixException x) {
+                        if (flags.failIfUnableToCopyPosix)
+                            x.rethrowAsIOException(target);
+                    }
+                    return;
+                }
+            } catch (IOException e) {
+                // clone or chown failed so roll back
+                try {
+                    unlink(target);
+                } catch (UnixException ignore) { }
+
+                throw e;
+            }
+
+            // fall through to superclass method
+       }
+
+        super.copyFile(source, attrs, target, flags, addressToPollForCancel);
+    }
+
     @Override
     void copyNonPosixAttributes(int ofd, int nfd) {
         UnixUserDefinedFileAttributeView.copyExtendedAttributes(ofd, nfd);

src/java.base/macosx/classes/sun/nio/fs/BsdNativeDispatcher.java

@@ -61,6 +61,26 @@ static byte[] getmntonname(UnixPath path) throws UnixException {
     }
     static native byte[] getmntonname0(long pathAddress) throws UnixException;
 
+    /**
+     * int clonefile(const char * src, const char * dst, int flags);
+     */
+    static int clonefile(UnixPath src, UnixPath dst, int flags)
+        throws UnixException
+    {
+        try (NativeBuffer srcBuffer = copyToNativeBuffer(src);
+            NativeBuffer dstBuffer = copyToNativeBuffer(dst)) {
+            long comp = Blocker.begin();
+            try {
+                return clonefile0(srcBuffer.address(), dstBuffer.address(),
+                                  flags);
+            } finally {
+                Blocker.end(comp);
+            }
+        }
+    }
+    private static native int clonefile0(long srcAddress, long dstAddress,
+                                         int flags);
+
     /**
      * setattrlist(const char* path, struct attrlist* attrList, void* attrBuf,
      *             size_t attrBufSize, unsigned long options)

src/java.base/macosx/native/libnio/fs/BsdNativeDispatcher.c

@@ -42,6 +42,8 @@
 
 #include <stdlib.h>
 #include <string.h>
+#include <sys/attr.h>
+#include <sys/clonefile.h>
 
 static jfieldID entry_name;
 static jfieldID entry_dir;
@@ -225,6 +227,22 @@ Java_sun_nio_fs_BsdNativeDispatcher_getmntonname0(JNIEnv *env, jclass this,
     return mntonname;
 }
 
+JNIEXPORT jint JNICALL
+Java_sun_nio_fs_BsdNativeDispatcher_clonefile0(JNIEnv* env, jclass this,
+    jlong srcAddress, jlong dstAddress, jint flags)
+{
+    const char* src = (const char*)jlong_to_ptr(srcAddress);
+    const char* dst = (const char*)jlong_to_ptr(dstAddress);
+
+    int ret = clonefile(src, dst, flags);
+    if (ret != 0) {
+        throwUnixException(env, errno);
+        return ret;
+    }
+
+    return 0;
+}
+
 JNIEXPORT void JNICALL
 Java_sun_nio_fs_BsdNativeDispatcher_setattrlist0(JNIEnv* env, jclass this,
     jlong pathAddress, int commonattr, jlong modTime, jlong accTime,

src/java.base/unix/classes/sun/nio/fs/UnixConstants.java.template

@@ -32,6 +32,7 @@
 #include <sys/stat.h>
 #ifdef _ALLBSD_SOURCE
 #include <sys/attr.h>
+#include <sys/clonefile.h>
 #endif
 
 /* To be able to name the Java constants the same as the C constants without
@@ -133,6 +134,10 @@ class UnixConstants {
     static final int PREFIX_ERANGE = ERANGE;
     static final int PREFIX_EMFILE = EMFILE;
 
+#ifdef _ALLBSD_SOURCE
+    static final int PREFIX_ENOTSUP = ENOTSUP;
+#endif
+
     // flags used with openat/unlinkat/etc.
 #if defined(AT_SYMLINK_NOFOLLOW) && defined(AT_REMOVEDIR)
     static final int PREFIX_AT_SYMLINK_NOFOLLOW = AT_SYMLINK_NOFOLLOW;
@@ -144,6 +149,10 @@ class UnixConstants {
 #endif
 
 #ifdef _ALLBSD_SOURCE
+    // flags used with clonefile
+    static final int PREFIX_CLONE_NOFOLLOW = CLONE_NOFOLLOW;
+    static final int PREFIX_CLONE_NOOWNERCOPY = CLONE_NOOWNERCOPY;
+
     // flags used with setattrlist
     static final int PREFIX_ATTR_CMN_CRTIME = ATTR_CMN_CRTIME;
     static final int PREFIX_ATTR_CMN_MODTIME = ATTR_CMN_MODTIME;

src/java.base/unix/classes/sun/nio/fs/UnixFileSystem.java

@@ -428,7 +428,7 @@ private static int temporaryBufferSize(UnixPath source, UnixPath target) {
     }
 
     // The flags that control how a file is copied or moved
-    private static class Flags {
+    protected static class Flags {
         boolean replaceExisting;
         boolean atomicMove;
         boolean followLinks;