Implement safety checks in SoT migration tool

Summary:
Now we check for:
- If the repo is enabled in config?
- If the repo is unlocked in the config for writing?
- If the repo is unlocked in the DB for writing?

I will also add a check for validating hooks are enabled for the repo in a follow up diff.

Reviewed By: markbt

Differential Revision: D63893886

fbshipit-source-id: 5b27189af92ecfc03619ee191740aea0ea820a7c

eden/mononoke/metaconfig/types/src/lib.rs

@@ -508,6 +508,16 @@ pub enum RepoReadOnly {
     ReadWrite,
 }
 
+impl RepoReadOnly {
+    /// Returns true if the repo is read-only
+    pub fn is_read_only(&self) -> bool {
+        match self {
+            RepoReadOnly::ReadOnly(_) => true,
+            RepoReadOnly::ReadWrite => false,
+        }
+    }
+}
+
 /// Configuration of warming up the Mononoke cache. This warmup happens on startup
 #[derive(Debug, Clone, Eq, PartialEq)]
 pub struct CacheWarmupParams {

eden/mononoke/repo_attributes/repo_lock/src/lib.rs

@@ -28,6 +28,16 @@ pub enum RepoLockState {
     Unlocked,
 }
 
+impl RepoLockState {
+    /// Returns true if the repo is locked, false otherwise.
+    pub fn is_locked(&self) -> bool {
+        match self {
+            RepoLockState::Locked(_) => true,
+            RepoLockState::Unlocked => false,
+        }
+    }
+}
+
 #[facet::facet]
 #[async_trait]
 pub trait RepoLock: Send + Sync {