Automated rollback of commit 82e68b75304438c96ff878a0c2b8d18b42002486.

Fixes #4322, #4306.

*** Reason for rollback ***

Introduces a deadlock (see https://github.com/bazelbuild/bazel/issues/4322)

*** Original change description ***

Make FileSystem operate on LocalPath instead of Path.

PiperOrigin-RevId: 179549866

1 files changed, 40 insertions, 11 deletions

diff --git a/src/main/java/com/google/devtools/build/lib/windows/WindowsFileSystem.java b/src/main/java/com/google/devtools/build/lib/windows/WindowsFileSystem.java
index c98a6c1f15..af97e27d3d 100644
--- a/src/main/java/com/google/devtools/build/lib/windows/WindowsFileSystem.java
+++ b/src/main/java/com/google/devtools/build/lib/windows/WindowsFileSystem.java
@@ -21,7 +21,6 @@ import com.google.devtools.build.lib.concurrent.ThreadSafety.ThreadSafe;
 import com.google.devtools.build.lib.vfs.FileStatus;
 import com.google.devtools.build.lib.vfs.FileSystem;
 import com.google.devtools.build.lib.vfs.JavaIoFileSystem;
-import com.google.devtools.build.lib.vfs.LocalPath;
 import com.google.devtools.build.lib.vfs.Path;
 import com.google.devtools.build.lib.vfs.Path.PathFactory;
 import com.google.devtools.build.lib.vfs.PathFragment;
@@ -33,11 +32,41 @@ import java.nio.file.Files;
 import java.nio.file.LinkOption;
 import java.nio.file.attribute.DosFileAttributes;
 import java.util.Arrays;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+import javax.annotation.Nullable;
 
 /** File system implementation for Windows. */
 @ThreadSafe
 public class WindowsFileSystem extends JavaIoFileSystem {
 
+  // Properties of 8dot3 (DOS-style) short file names:
+  // - they are at most 11 characters long
+  // - they have a prefix (before "~") that is {1..6} characters long, may contain numbers, letters,
+  //   "_", even "~", and maybe even more
+  // - they have a "~" after the prefix
+  // - have {1..6} numbers after "~" (according to [1] this is only one digit, but MSDN doesn't
+  //   clarify this), the combined length up till this point is at most 8
+  // - they have an optional "." afterwards, and another {0..3} more characters
+  // - just because a path looks like a short name it isn't necessarily one; the user may create
+  //   such names and they'd resolve to themselves
+  // [1] https://en.wikipedia.org/wiki/8.3_filename#VFAT_and_Computer-generated_8.3_filenames
+  //     bullet point (3) (on 2016-12-05)
+  @VisibleForTesting
+  static final Predicate<String> SHORT_NAME_MATCHER =
+      new Predicate<String>() {
+        private final Pattern pattern = Pattern.compile("^(.{1,6})~([0-9]{1,6})(\\..{0,3}){0,1}");
+
+        @Override
+        public boolean apply(@Nullable String input) {
+          Matcher m = pattern.matcher(input);
+          return input.length() <= 12
+              && m.matches()
+              && m.groupCount() >= 2
+              && (m.group(1).length() + m.group(2).length()) < 8; // the "~" makes it at most 8
+        }
+      };
+
   /** Resolves DOS-style, shortened path names, returning the last segment's long form. */
   private static final Function<String, String> WINDOWS_SHORT_PATH_RESOLVER =
       path -> {
@@ -85,7 +114,7 @@ public class WindowsFileSystem extends JavaIoFileSystem {
       }
 
       String resolvedChild = child;
-      if (parent != null && !parent.isRootDirectory() && WindowsShortPath.isShortPath(child)) {
+      if (parent != null && !parent.isRootDirectory() && SHORT_NAME_MATCHER.apply(child)) {
         String pathString = parent.getPathString();
         if (!pathString.endsWith("/")) {
           pathString += "/";
@@ -257,18 +286,18 @@ public class WindowsFileSystem extends JavaIoFileSystem {
   }
 
   @Override
-  public String getFileSystemType(LocalPath path) {
+  public String getFileSystemType(Path path) {
     // TODO(laszlocsomor): implement this properly, i.e. actually query this information from
     // somewhere (java.nio.Filesystem? System.getProperty? implement JNI method and use WinAPI?).
     return "ntfs";
   }
 
   @Override
-  protected void createSymbolicLink(LocalPath linkPath, String targetFragment) throws IOException {
-    LocalPath targetPath = LocalPath.create(targetFragment);
-    if (!targetPath.isAbsolute()) {
-      targetPath = linkPath.getParentDirectory().getRelative(targetPath);
-    }
+  protected void createSymbolicLink(Path linkPath, PathFragment targetFragment) throws IOException {
+    Path targetPath =
+        targetFragment.isAbsolute()
+            ? getPath(targetFragment)
+            : linkPath.getParentDirectory().getRelative(targetFragment);
     try {
       java.nio.file.Path link = getIoFile(linkPath).toPath();
       java.nio.file.Path target = getIoFile(targetPath).toPath();
@@ -288,7 +317,7 @@ public class WindowsFileSystem extends JavaIoFileSystem {
   }
 
   @Override
-  public boolean supportsSymbolicLinksNatively(LocalPath path) {
+  public boolean supportsSymbolicLinksNatively(Path path) {
     return false;
   }
 
@@ -314,7 +343,7 @@ public class WindowsFileSystem extends JavaIoFileSystem {
   }
 
   @Override
-  protected FileStatus stat(LocalPath path, boolean followSymlinks) throws IOException {
+  protected FileStatus stat(Path path, boolean followSymlinks) throws IOException {
     File file = getIoFile(path);
     final DosFileAttributes attributes;
     try {
@@ -373,7 +402,7 @@ public class WindowsFileSystem extends JavaIoFileSystem {
   }
 
   @Override
-  protected boolean isDirectory(LocalPath path, boolean followSymlinks) {
+  protected boolean isDirectory(Path path, boolean followSymlinks) {
     if (!followSymlinks) {
       try {
         if (isJunction(getIoFile(path))) {