Move is_eden_fs_mount to common/utils

Summary:
Moves is_eden_fs_mount out of watchman into eden/common/utils

This function checks if an entry in the mount table is an edenfs mount by seeing if it starts with `edenfs:`

The intention is to have a single source of determining what entries are eden mounts to prevent duplicated code

TARGETS changes by autodeps

Reviewed By: genevievehelsel

Differential Revision: D62528347

fbshipit-source-id: b1edf7e811334de815c5255e5d3dc9536d177fb8

eden/common/utils/FSDetect.h

@@ -0,0 +1,28 @@
+/*
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+#pragma once
+
+#include <string>
+
+#include <folly/Range.h>
+
+namespace facebook::eden {
+
+inline bool is_edenfs_fs_type(folly::StringPiece fs_type) {
+  return !fs_type.empty() &&
+      (fs_type == "edenfs" || fs_type.startsWith("edenfs:"));
+}
+
+inline bool is_edenfs_fs_mount(
+    folly::StringPiece line_entry,
+    const std::string& mountPoint) {
+  return is_edenfs_fs_type(line_entry) &&
+      line_entry.find(mountPoint) != std::string::npos;
+}
+
+} // namespace facebook::eden