speedup checking value in db

Author: pashinov

Cargo.lock

@@ -136,6 +136,7 @@ tycho-util = { path = "./util", version = "0.2.8" }
 
 [patch.crates-io]
 everscale-types = { git = "https://github.com/broxus/everscale-types.git", rev = "048b934f6fcc4e5d3c1199af08ab6d20aa4f9471" }
+weedb = { git = "https://github.com/broxus/weedb.git", rev = "af2bbc262b6ea9282cd9d29ec5062db040ea40e5" }
 
 [workspace.lints.rust]
 future_incompatible = "warn"

Cargo.toml

@@ -482,6 +482,10 @@ impl StoreContext {
                 }
             }
 
+            if !self.db.cells.key_may_exist(key) {
+                break 'value (0, false);
+            }
+
             match self.db.cells.get(key).map_err(CellStorageError::Internal)? {
                 Some(value) => {
                     let (rc, value) = refcount::decode_value_with_rc(value.as_ref());