JBR-9779 Refactor: extract common logic for getting nio path in FileInputStream, RandomAccessFile, and FileOutputStream

Author: vladimirlagunov

src/java.base/share/classes/java/io/FileInputStream.java

@@ -28,7 +28,6 @@
 import java.nio.ByteBuffer;
 import java.nio.channels.FileChannel;
 import java.nio.file.Files;
-import java.nio.file.InvalidPathException;
 import java.nio.file.Path;
 import java.nio.file.StandardOpenOption;
 import java.util.Arrays;
@@ -158,25 +157,11 @@ public FileInputStream(File file) throws FileNotFoundException {
 
         try (var guard = IoOverNio.RecursionGuard.create(FileInputStream.class)) {
             IoOverNio.blackhole(guard);
-            java.nio.file.FileSystem nioFs = IoOverNioFileSystem.acquireNioFs(path);
-            Path nioPath = null;
-            if (nioFs != null && path != null) {
-                try {
-                    nioPath = nioFs.getPath(path);
-                    isRegularFile = Files.isRegularFile(nioPath);
-                } catch (InvalidPathException _) {
-                    // Nothing.
-                }
-            }
-
-            // Two significant differences between the legacy java.io and java.nio.files:
-            // * java.nio.file allows to open directories as streams, java.io.FileInputStream doesn't.
-            // * java.nio.file doesn't work well with pseudo devices, i.e., `seek()` fails, while java.io works well.
-            useNio = nioPath != null && isRegularFile == Boolean.TRUE;
-
+            Path nioPath = IoOverNioFileSystem.getNioPath(file, true);
+            useNio = nioPath != null;
             if (useNio) {
                 var bundle = IoOverNioFileSystem.initializeStreamUsingNio(
-                        this, nioFs, file, nioPath, Set.of(StandardOpenOption.READ), channelCleanable);
+                        this, nioPath.getFileSystem(), file, nioPath, Set.of(StandardOpenOption.READ), channelCleanable);
                 channel = bundle.channel();
                 fd = bundle.fd();
                 externalChannelHolder = bundle.externalChannelHolder();

src/java.base/share/classes/java/io/FileOutputStream.java

@@ -227,11 +227,10 @@ public FileOutputStream(File file, boolean append)
 
         try (var guard = IoOverNio.RecursionGuard.create(FileOutputStream.class)) {
             IoOverNio.blackhole(guard);
-            java.nio.file.FileSystem nioFs = IoOverNioFileSystem.acquireNioFs(path);
-            useNio = path != null && nioFs != null;
+            Path nioPath = IoOverNioFileSystem.getNioPath(file, false);
+            useNio = nioPath != null;
             if (useNio) {
-                Path nioPath = nioFs.getPath(path);
-
+                java.nio.file.FileSystem nioFs = nioPath.getFileSystem();
                 // java.io backend doesn't open DOS hidden files for writing, but java.nio.file opens.
                 // This code mimics the old behavior.
                 if (nioFs.getSeparator().equals("\\")) {

src/java.base/share/classes/java/io/IoOverNioFileSystem.java

@@ -41,6 +41,7 @@
 import java.nio.file.Files;
 import java.nio.file.InvalidPathException;
 import java.nio.file.LinkOption;
+import java.nio.file.NoSuchFileException;
 import java.nio.file.OpenOption;
 import java.nio.file.Path;
 import java.nio.file.StandardCopyOption;
@@ -123,6 +124,40 @@ static FileNotFoundException convertNioToIoExceptionInStreams(IOException source
         return result;
     }
 
+    static Path getNioPath(File file, boolean mustBeRegularFile) {
+        String path = file.getPath();
+        java.nio.file.FileSystem nioFs = IoOverNioFileSystem.acquireNioFs(path);
+        if (nioFs == null) {
+            return null;
+        }
+
+        Path nioPath;
+        try {
+            nioPath = nioFs.getPath(path);
+        } catch (InvalidPathException _) {
+            return null;
+        }
+
+        if (!mustBeRegularFile) {
+            return nioPath;
+        }
+
+        // Two significant differences between the legacy java.io and java.nio.files:
+        // * java.nio.file allows to open directories as streams, java.io.FileInputStream doesn't.
+        // * java.nio.file doesn't work well with pseudo devices, i.e., `seek()` fails, while java.io works well.
+        try {
+            if (Files.readAttributes(nioPath, BasicFileAttributes.class, LinkOption.NOFOLLOW_LINKS).isRegularFile()) {
+                return nioPath;
+            }
+        } catch (NoSuchFileException _) {
+            return nioPath;
+        } catch (IOException _) {
+            // Ignored.
+        }
+
+        return null;
+    }
+
     private static boolean setPermission0(java.nio.file.FileSystem nioFs, File f, int access, boolean enable, boolean owneronly) {
         if (f.getPath().isEmpty()) {
             if (nioFs.getSeparator().equals("\\")) {

src/java.base/share/classes/java/io/RandomAccessFile.java

@@ -27,16 +27,11 @@
 
 import java.nio.ByteBuffer;
 import java.nio.channels.FileChannel;
+import java.nio.file.Path;
+
 import java.nio.channels.NonWritableChannelException;
-import java.nio.file.FileSystem;
-import java.nio.file.Files;
-import java.nio.file.InvalidPathException;
-import java.nio.file.LinkOption;
-import java.nio.file.NoSuchFileException;
 import java.nio.file.OpenOption;
-import java.nio.file.Path;
 import java.nio.file.StandardOpenOption;
-import java.nio.file.attribute.BasicFileAttributes;
 import java.util.Arrays;
 import java.util.HashSet;
 
@@ -281,35 +276,11 @@ else if (mode.startsWith("rw")) {
 
         try (var guard = IoOverNio.RecursionGuard.create(RandomAccessFile.class)) {
             IoOverNio.blackhole(guard);
-            FileSystem nioFs = IoOverNioFileSystem.acquireNioFs(path);
-            Path nioPath = null;
-            if (nioFs != null) {
-                try {
-                    nioPath = nioFs.getPath(path);
-                } catch (InvalidPathException _) {
-                    // Nothing.
-                }
-            }
-
-            // Two significant differences between the legacy java.io and java.nio.files:
-            // * java.nio.file allows to open directories as streams, java.io.FileInputStream doesn't.
-            // * java.nio.file doesn't work well with pseudo devices, i.e., `seek()` fails, while java.io works well.
-            boolean isRegularFile;
-            try {
-                isRegularFile = nioPath != null &&
-                        Files.readAttributes(nioPath, BasicFileAttributes.class, LinkOption.NOFOLLOW_LINKS).isRegularFile();
-            }
-            catch (NoSuchFileException _) {
-                isRegularFile = true;
-            }
-            catch (IOException _) {
-                isRegularFile = false;
-            }
-
-            useNio = nioPath != null && isRegularFile;
+            Path nioPath = IoOverNioFileSystem.getNioPath(file, true);
+            useNio = nioPath != null;
             if (useNio) {
                 var bundle = IoOverNioFileSystem.initializeStreamUsingNio(
-                        this, nioFs, file, nioPath, optionsForChannel(imode), channelCleanable);
+                        this, nioPath.getFileSystem(), file, nioPath, optionsForChannel(imode), channelCleanable);
                 channel = bundle.channel();
                 fd = bundle.fd();
                 externalChannelHolder = bundle.externalChannelHolder();