refactor: Reduce number of LoadChainstate return values

1 files changed, 12 insertions, 37 deletions

diff --git a/src/node/chainstate.h b/src/node/chainstate.h
index 4851ef1ae6..649cfb2526 100644
--- a/src/node/chainstate.h
+++ b/src/node/chainstate.h
@@ -31,18 +31,14 @@ struct ChainstateLoadOptions {
     std::function<void()> coins_error_cb;
 };
 
-enum class ChainstateLoadingError {
-    ERROR_LOADING_BLOCK_DB,
-    ERROR_BAD_GENESIS_BLOCK,
-    ERROR_PRUNED_NEEDS_REINDEX,
-    ERROR_LOAD_GENESIS_BLOCK_FAILED,
-    ERROR_CHAINSTATE_UPGRADE_FAILED,
-    ERROR_REPLAYBLOCKS_FAILED,
-    ERROR_LOADCHAINTIP_FAILED,
-    ERROR_GENERIC_BLOCKDB_OPEN_FAILED,
-    ERROR_BLOCKS_WITNESS_INSUFFICIENTLY_VALIDATED,
-    SHUTDOWN_PROBED,
-};
+//! Chainstate load status. Simple applications can just check for the success
+//! case, and treat other cases as errors. More complex applications may want to
+//! try reindexing in the generic failure case, and pass an interrupt callback
+//! and exit cleanly in the interrupted case.
+enum class ChainstateLoadStatus { SUCCESS, FAILURE, FAILURE_INCOMPATIBLE_DB, INTERRUPTED };
+
+//! Chainstate load status code and optional error string.
+using ChainstateLoadResult = std::tuple<ChainstateLoadStatus, bilingual_str>;
 
 /** This sequence can have 4 types of outcomes:
  *
@@ -55,32 +51,11 @@ enum class ChainstateLoadingError {
  *  4. Hard failure
  *    - a failure that definitively cannot be recovered from with a reindex
  *
- *  Currently, LoadChainstate returns a std::optional<ChainstateLoadingError>
- *  which:
- *
- *  - if has_value()
- *      - Either "Soft failure", "Hard failure", or "Shutdown requested",
- *        differentiable by the specific enumerator.
- *
- *        Note that a return value of SHUTDOWN_PROBED means ONLY that "during
- *        this sequence, when we explicitly checked shutdown_requested() at
- *        arbitrary points, one of those calls returned true". Therefore, a
- *        return value other than SHUTDOWN_PROBED does not guarantee that
- *        shutdown hasn't been called indirectly.
- *  - else
- *      - Success!
+ *  LoadChainstate returns a (status code, error string) tuple.
  */
-std::optional<ChainstateLoadingError> LoadChainstate(ChainstateManager& chainman, const CacheSizes& cache_sizes,
-                                                     const ChainstateLoadOptions& options);
-
-enum class ChainstateLoadVerifyError {
-    ERROR_BLOCK_FROM_FUTURE,
-    ERROR_CORRUPTED_BLOCK_DB,
-    ERROR_GENERIC_FAILURE,
-};
-
-std::optional<ChainstateLoadVerifyError> VerifyLoadedChainstate(ChainstateManager& chainman,
-                                                                const ChainstateLoadOptions& options);
+ChainstateLoadResult LoadChainstate(ChainstateManager& chainman, const CacheSizes& cache_sizes,
+                                    const ChainstateLoadOptions& options);
+ChainstateLoadResult VerifyLoadedChainstate(ChainstateManager& chainman, const ChainstateLoadOptions& options);
 } // namespace node
 
 #endif // BITCOIN_NODE_CHAINSTATE_H