From 990af745e22a7c5095bc4691574c3dbba44bc501 Mon Sep 17 00:00:00 2001
From: Xavier Deguillard <xavierd@fb.com>
Date: Wed, 3 Feb 2021 16:43:32 -0800
Subject: [PATCH] config: add a per-repo mount protocol

Summary:
On macOS, EdenFS will soon be exposed as an NFS server. To ease the transition,
let's have a per-mount config to decide whether this repository should be
mounted via FUSE or NFS

Reviewed By: genevievehelsel

Differential Revision: D26139992

fbshipit-source-id: d28b0e2327c1101f3555ab0bbc9a5b03d82fd7ff
---
 eden/fs/config/CheckoutConfig.cpp | 20 ++++++++++++++++++++
 eden/fs/config/CheckoutConfig.h   | 14 ++++++++++++++
 2 files changed, 34 insertions(+)

diff --git a/eden/fs/config/CheckoutConfig.cpp b/eden/fs/config/CheckoutConfig.cpp
index a91389503a..f83d3b9813 100644
--- a/eden/fs/config/CheckoutConfig.cpp
+++ b/eden/fs/config/CheckoutConfig.cpp
@@ -30,10 +30,24 @@ constexpr folly::StringPiece kRepoSection{"repository"};
 constexpr folly::StringPiece kRepoSourceKey{"path"};
 constexpr folly::StringPiece kRepoTypeKey{"type"};
 constexpr folly::StringPiece kRepoCaseSensitiveKey{"case-sensitive"};
+constexpr folly::StringPiece kMountProtocol{"protocol"};
 #ifdef _WIN32
 constexpr folly::StringPiece kRepoGuid{"guid"};
 #endif
 
+#ifdef _WIN32
+constexpr folly::StringPiece kMountProtocolPrjfs{"prjfs"};
+#else
+constexpr folly::StringPiece kMountProtocolFuse{"fuse"};
+#endif
+constexpr folly::StringPiece kMountProtocolNFS{"nfs"};
+
+#ifdef _WIN32
+constexpr folly::StringPiece kMountProtocolDefault{kMountProtocolPrjfs};
+#else
+constexpr folly::StringPiece kMountProtocolDefault{kMountProtocolFuse};
+#endif
+
 // Files of interest in the client directory.
 const facebook::eden::RelativePathPiece kSnapshotFile{"SNAPSHOT"};
 const facebook::eden::RelativePathPiece kOverlayDir{"local"};
@@ -175,6 +189,12 @@ std::unique_ptr<CheckoutConfig> CheckoutConfig::loadFromClientDirectory(
   config->repoType_ = *repository->get_as<std::string>(kRepoTypeKey.str());
   config->repoSource_ = *repository->get_as<std::string>(kRepoSourceKey.str());
 
+  auto mountProtocol = repository->get_as<std::string>(kMountProtocol.str())
+                           .value_or(kMountProtocolDefault);
+  config->mountProtocol_ = mountProtocol == kMountProtocolNFS
+      ? MountProtocol::NFS
+      : (folly::kIsWindows ? MountProtocol::PRJFS : MountProtocol::FUSE);
+
   // Read optional case-sensitivity.
   auto caseSensitive = repository->get_as<bool>(kRepoCaseSensitiveKey.str());
   config->caseSensitive_ =
diff --git a/eden/fs/config/CheckoutConfig.h b/eden/fs/config/CheckoutConfig.h
index 4e135ebf10..c30d87baa4 100644
--- a/eden/fs/config/CheckoutConfig.h
+++ b/eden/fs/config/CheckoutConfig.h
@@ -20,6 +20,12 @@
 namespace facebook {
 namespace eden {
 
+enum class MountProtocol {
+  FUSE,
+  PRJFS,
+  NFS,
+};
+
 /**
  * CheckoutConfig contains the configuration state for a single Eden checkout.
  *
@@ -83,6 +89,13 @@ class CheckoutConfig {
     return repoType_;
   }
 
+  /**
+   * Get the channel type that this mount should be using.
+   */
+  MountProtocol getMountProtocol() const {
+    return mountProtocol_;
+  }
+
   /**
    * Get the repository source.
    *
@@ -115,6 +128,7 @@ class CheckoutConfig {
   const AbsolutePath mountPath_;
   std::string repoType_;
   std::string repoSource_;
+  MountProtocol mountProtocol_;
   bool caseSensitive_{!folly::kIsWindows};
 #ifdef _WIN32
   Guid repoGuid_;