Make it able to inject non-remote file into RemoteInMemoryFileSystem.

In following CLs, we want to implement 'copy' semantic for `ctx.actions.symlink` in RemoteInMemoryFileSystem, i.e. instead of creating a symlink in `#createSymbolicLink`, we want to copy the target metadata to the link path.

There are cases where the target metadata is not a remote metadata, e.g. symlink to source, symlink to output of local action, etc. So we need to support inject non-remote metadata into RemoteInMemoryFileSystem.

PiperOrigin-RevId: 536994360
Change-Id: I1696db007304d638903b7250b8478491aef76795

src/main/java/com/google/devtools/build/lib/remote/RemoteActionFileSystem.java

@@ -130,7 +130,9 @@ void injectRemoteFile(PathFragment path, byte[] digest, long size, long expireAt
     if (!isOutput(path)) {
       return;
     }
-    remoteOutputTree.injectRemoteFile(path, digest, size, expireAtEpochMilli);
+    var metadata =
+        RemoteFileArtifactValue.create(digest, size, /* locationIndex= */ 1, expireAtEpochMilli);
+    remoteOutputTree.injectFile(path, metadata);
   }
 
   void flush() throws IOException, InterruptedException {
@@ -574,11 +576,10 @@ private FileArtifactValue getMetadataByExecPath(PathFragment execPath) {
       return m;
     }
 
-    RemoteFileInfo remoteFile =
-        remoteOutputTree.getRemoteFileInfo(
-            execRoot.getRelative(execPath), /* followSymlinks= */ true);
-    if (remoteFile != null) {
-      return remoteFile.getMetadata();
+    var stat =
+        remoteOutputTree.statNullable(execRoot.getRelative(execPath), /* followSymlinks= */ true);
+    if (stat instanceof FileStatusWithMetadata) {
+      return ((FileStatusWithMetadata) stat).getMetadata();
     }
 
     return null;
@@ -783,44 +784,38 @@ protected synchronized OutputStream getOutputStream(PathFragment path, boolean a
 
     @Override
     protected FileInfo newFile(Clock clock, PathFragment path) {
-      return new RemoteFileInfo(clock);
+      return new RemoteInMemoryFileInfo(clock);
     }
 
-    void injectRemoteFile(PathFragment path, byte[] digest, long size, long expireAtEpochMilli)
-        throws IOException {
+    protected void injectFile(PathFragment path, FileArtifactValue metadata) throws IOException {
       createDirectoryAndParents(path.getParentDirectory());
       InMemoryContentInfo node = getOrCreateWritableInode(path);
       // If a node was already existed and is not a remote file node (i.e. directory or symlink node
       // ), throw an error.
-      if (!(node instanceof RemoteFileInfo)) {
+      if (!(node instanceof RemoteInMemoryFileInfo)) {
         throw new IOException("Could not inject into " + node);
       }
 
-      RemoteFileInfo remoteFileInfo = (RemoteFileInfo) node;
-
-      var metadata =
-          RemoteFileArtifactValue.create(digest, size, /* locationIndex= */ 1, expireAtEpochMilli);
-      remoteFileInfo.set(metadata);
+      RemoteInMemoryFileInfo remoteInMemoryFileInfo = (RemoteInMemoryFileInfo) node;
+      remoteInMemoryFileInfo.set(metadata);
     }
 
+    // Override for access within this class
     @Nullable
-    RemoteFileInfo getRemoteFileInfo(PathFragment path, boolean followSymlinks) {
-      InMemoryContentInfo node = inodeStatErrno(path, followSymlinks).inode();
-      if (!(node instanceof RemoteFileInfo)) {
-        return null;
-      }
-      return (RemoteFileInfo) node;
+    @Override
+    protected FileStatus statNullable(PathFragment path, boolean followSymlinks) {
+      return super.statNullable(path, followSymlinks);
     }
   }
 
-  static class RemoteFileInfo extends FileInfo implements FileStatusWithMetadata {
-    private RemoteFileArtifactValue metadata;
+  static class RemoteInMemoryFileInfo extends FileInfo implements FileStatusWithMetadata {
+    private FileArtifactValue metadata;
 
-    RemoteFileInfo(Clock clock) {
+    RemoteInMemoryFileInfo(Clock clock) {
       super(clock);
     }
 
-    private void set(RemoteFileArtifactValue metadata) {
+    private void set(FileArtifactValue metadata) {
       this.metadata = metadata;
     }
 
@@ -854,12 +849,8 @@ public long getSize() {
       return metadata.getSize();
     }
 
-    public long getExpireAtEpochMilli() {
-      return metadata.getExpireAtEpochMilli();
-    }
-
     @Override
-    public RemoteFileArtifactValue getMetadata() {
+    public FileArtifactValue getMetadata() {
       return metadata;
     }
   }