refactor: index, decouple 'Init' from 'Start'

So indexes can be initialized without spawning
the sync thread.

This makes asynchronous indexes startup
possible in the following commits.

1 files changed, 8 insertions, 6 deletions

diff --git a/src/index/base.h b/src/index/base.h
index 8affee90f8..8b986fe8c4 100644
--- a/src/index/base.h
+++ b/src/index/base.h
@@ -54,6 +54,8 @@ protected:
     };
 
 private:
+    /// Whether the index has been initialized or not.
+    std::atomic<bool> m_init{false};
     /// Whether the index is in sync with the main chain. The flag is flipped
     /// from false to true once, after which point this starts processing
     /// ValidationInterface notifications to stay in sync.
@@ -69,9 +71,6 @@ private:
     std::thread m_thread_sync;
     CThreadInterrupt m_interrupt;
 
-    /// Read best block locator and check that data needed to sync has not been pruned.
-    bool Init();
-
     /// Sync the index with the block index starting from the current best block.
     /// Intended to be run in its own thread, m_thread_sync, and can be
     /// interrupted with m_interrupt. Once the index gets in sync, the m_synced
@@ -142,9 +141,12 @@ public:
 
     void Interrupt();
 
-    /// Start initializes the sync state and registers the instance as a
-    /// ValidationInterface so that it stays in sync with blockchain updates.
-    [[nodiscard]] bool Start();
+    /// Initializes the sync state and registers the instance to the
+    /// validation interface so that it stays in sync with blockchain updates.
+    [[nodiscard]] bool Init();
+
+    /// Starts the initial sync process.
+    [[nodiscard]] bool StartBackgroundSync();
 
     /// Stops the instance from staying in sync with blockchain updates.
     void Stop();