Extract NIO to IO exception conversion into a helper method

Author: fmeum

src/main/java/com/google/devtools/build/lib/vfs/FileSystem.java

@@ -30,7 +30,13 @@
 import java.io.InputStreamReader;
 import java.io.OutputStream;
 import java.nio.channels.SeekableByteChannel;
+import java.nio.file.AccessDeniedException;
+import java.nio.file.DirectoryNotEmptyException;
 import java.nio.file.FileAlreadyExistsException;
+import java.nio.file.FileSystemException;
+import java.nio.file.NoSuchFileException;
+import java.nio.file.NotDirectoryException;
+import java.nio.file.NotLinkException;
 import java.security.SecureRandom;
 import java.util.Collection;
 import java.util.Iterator;
@@ -45,6 +51,15 @@ public abstract class FileSystem {
   // canonicalizing a path before it gives up and throws a FileSymlinkLoopException.
   public static final int MAX_SYMLINKS = 32;
 
+  // Standard error message suffixes to be used for consistency across different FileSystem
+  // implementations.
+  protected static final String ERR_DIRECTORY_NOT_EMPTY = " (Directory not empty)";
+  protected static final String ERR_FILE_EXISTS = " (File exists)";
+  protected static final String ERR_IS_DIRECTORY = " (Is a directory)";
+  protected static final String ERR_NOT_A_DIRECTORY = " (Not a directory)";
+  protected static final String ERR_NO_SUCH_FILE_OR_DIR = " (No such file or directory)";
+  protected static final String ERR_PERMISSION_DENIED = " (Permission denied)";
+
   private final DigestHashFunction digestFunction;
 
   public FileSystem(DigestHashFunction digestFunction) {
@@ -797,6 +812,55 @@ public java.nio.file.Path getNioPath(PathFragment path) {
         "getNioPath() not supported for " + getClass().getName());
   }
 
+  /**
+   * Translates common java.nio.file IOExceptions into the equivalent java.io IOExceptions with
+   * consistent error messages.
+   */
+  protected static IOException translateNioToIoException(PathFragment path, IOException e) {
+    if (!(e instanceof FileSystemException fileSystemException)) {
+      return e;
+    }
+    String prefix = "";
+    if (fileSystemException.getFile() != null) {
+      prefix = fileSystemException.getFile();
+    }
+    if (fileSystemException.getOtherFile() != null) {
+      prefix += " -> " + fileSystemException.getOtherFile();
+    }
+    return switch (e) {
+      case AccessDeniedException unused -> {
+        FileAccessException newException = new FileAccessException(prefix + ERR_PERMISSION_DENIED);
+        newException.initCause(e);
+        yield newException;
+      }
+      case DirectoryNotEmptyException unused ->
+          new IOException(prefix + ERR_DIRECTORY_NOT_EMPTY, e);
+      case FileAlreadyExistsException unused -> new IOException(prefix + ERR_FILE_EXISTS, e);
+      case NoSuchFileException unused -> {
+        FileNotFoundException newException =
+            new FileNotFoundException(prefix + ERR_NO_SUCH_FILE_OR_DIR);
+        newException.initCause(e);
+        yield newException;
+      }
+      case NotDirectoryException unused -> new IOException(prefix + ERR_NOT_A_DIRECTORY, e);
+      case NotLinkException unused -> new NotASymlinkException(path, e);
+      // Rewrite exception messages to be identical to the ones produced by the native Unix
+      // filesystem implementation. Bazel forces the root locale for the JVM, so the error messages
+      // should be stable. Some of the exceptions caught above can also appear as untyped
+      // FileSystemExceptions, so we need to catch those as well.
+      case FileSystemException unused
+          when fileSystemException.getReason().equals("Is a directory") ->
+          new IOException(prefix + ERR_IS_DIRECTORY, e);
+      case FileSystemException unused
+          when fileSystemException.getReason().equals("Not a directory") ->
+          new IOException(prefix + ERR_NOT_A_DIRECTORY, e);
+      case FileSystemException unused
+          when fileSystemException.getReason().equals("Directory not empty") ->
+          new IOException(prefix + ERR_DIRECTORY_NOT_EMPTY, e);
+      default -> fileSystemException;
+    };
+  }
+
   /**
    * Returns the path of a new temporary directory with the given prefix created under the given
    * parent path, but <b>not</b> necessarily with secure permissions.

src/main/java/com/google/devtools/build/lib/vfs/JavaIoFileSystem.java

@@ -24,12 +24,9 @@
 import java.io.File;
 import java.io.FileNotFoundException;
 import java.io.IOException;
-import java.nio.file.AccessDeniedException;
-import java.nio.file.FileSystemException;
 import java.nio.file.Files;
 import java.nio.file.InvalidPathException;
 import java.nio.file.LinkOption;
-import java.nio.file.NoSuchFileException;
 import java.nio.file.Paths;
 import java.nio.file.StandardCopyOption;
 import java.nio.file.attribute.BasicFileAttributes;
@@ -54,12 +51,6 @@ public class JavaIoFileSystem extends AbstractFileSystem {
 
   private final Clock clock;
 
-  protected static final String ERR_IS_DIRECTORY = " (Is a directory)";
-  protected static final String ERR_DIRECTORY_NOT_EMPTY = " (Directory not empty)";
-  protected static final String ERR_FILE_EXISTS = " (File exists)";
-  protected static final String ERR_NO_SUCH_FILE_OR_DIR = " (No such file or directory)";
-  protected static final String ERR_NOT_A_DIRECTORY = " (Not a directory)";
-
   public JavaIoFileSystem(DigestHashFunction hashFunction) {
     super(hashFunction);
     this.clock = new JavaClock();
@@ -289,12 +280,8 @@ public void createSymbolicLink(
       Files.createSymbolicLink(
           nioPath,
           Paths.get(StringEncoding.internalToPlatform(targetFragment.getSafePathString())));
-    } catch (java.nio.file.FileAlreadyExistsException e) {
-      throw new IOException(linkPath + ERR_FILE_EXISTS, e);
-    } catch (java.nio.file.AccessDeniedException e) {
-      throw new IOException(linkPath + ERR_PERMISSION_DENIED, e);
-    } catch (java.nio.file.NoSuchFileException e) {
-      throw new FileNotFoundException(linkPath + ERR_NO_SUCH_FILE_OR_DIR);
+    } catch (IOException e) {
+      throw translateNioToIoException(linkPath, e);
     }
   }
 
@@ -305,10 +292,8 @@ public PathFragment readSymbolicLink(PathFragment path) throws IOException {
     try {
       String link = Files.readSymbolicLink(nioPath).toString();
       return PathFragment.create(StringEncoding.platformToInternal(link));
-    } catch (java.nio.file.NotLinkException e) {
-      throw new NotASymlinkException(path, e);
-    } catch (java.nio.file.NoSuchFileException e) {
-      throw new FileNotFoundException(path + ERR_NO_SUCH_FILE_OR_DIR);
+    } catch (IOException e) {
+      throw translateNioToIoException(path, e);
     } finally {
       profiler.logSimpleTask(startTime, ProfilerTask.VFS_READLINK, path.getPathString());
     }
@@ -318,32 +303,11 @@ public PathFragment readSymbolicLink(PathFragment path) throws IOException {
   public void renameTo(PathFragment sourcePath, PathFragment targetPath) throws IOException {
     java.nio.file.Path source = getNioPath(sourcePath);
     java.nio.file.Path target = getNioPath(targetPath);
-    // Replace NIO exceptions with the types used by the native Unix filesystem implementation where
-    // necessary.
     try {
       Files.move(
           source, target, StandardCopyOption.ATOMIC_MOVE, StandardCopyOption.REPLACE_EXISTING);
-    } catch (NoSuchFileException originalException) {
-      FileNotFoundException newException =
-          new FileNotFoundException(originalException.getMessage() + ERR_NO_SUCH_FILE_OR_DIR);
-      newException.initCause(originalException);
-      throw newException;
-    } catch (AccessDeniedException originalException) {
-      FileAccessException newException =
-          new FileAccessException(originalException.getMessage() + ERR_PERMISSION_DENIED);
-      newException.initCause(originalException);
-      throw newException;
-    } catch (FileSystemException e) {
-      // Rewrite exception messages to be identical to the ones produced by the native Unix
-      // filesystem implementation. Bazel forces the root locale for the JVM, so the error messages
-      // should be stable.
-      String filesPart = sourcePath + " -> " + targetPath;
-      throw switch (e.getReason()) {
-        case "Directory not empty" -> new IOException(filesPart + ERR_DIRECTORY_NOT_EMPTY, e);
-        case "Not a directory" -> new IOException(filesPart + ERR_NOT_A_DIRECTORY, e);
-        case "Is a directory" -> new IOException(filesPart + ERR_IS_DIRECTORY, e);
-        default -> e;
-      };
+    } catch (IOException e) {
+      throw translateNioToIoException(sourcePath, e);
     }
   }