Remove the score except it of the Header and the Block

Author: SeungMin Lee

core/src/block.rs

@@ -143,7 +143,6 @@ impl<'x> OpenBlock<'x> {
         r.block.header.set_extra_data(extra_data);
         r.block.header.note_dirty();
 
-        engine.machine().populate_from_parent(&mut r.block.header, parent);
         engine.populate_from_parent(&mut r.block.header, parent);
 
         Ok(r)
@@ -208,7 +207,6 @@ impl<'x> OpenBlock<'x> {
 
     /// Populate self from a header.
     fn populate_from(&mut self, header: &Header) {
-        self.block.header.set_score(*header.score());
         self.block.header.set_timestamp(header.timestamp());
         self.block.header.set_author(*header.author());
         self.block.header.set_extra_data(header.extra_data().clone());

core/src/blockchain/blockchain.rs

@@ -210,6 +210,13 @@ impl BlockChain {
         }
     }
 
+    /// Compare the number and the view of current block with these of best block
+    fn is_new_header_eligible_to_be_best(&self, new_header: &HeaderView<'_>) -> bool {
+        let details_of_best_block = self.best_proposal_block_detail();
+
+        (new_header.number(), details_of_best_block.view) > (details_of_best_block.number, new_header.view())
+    }
+
     /// Calculate how best block is changed
     fn best_block_changed(&self, new_block: &BlockView<'_>, engine: &dyn CodeChainEngine) -> BestBlockChanged {
         let new_header = new_block.header_view();
@@ -218,7 +225,7 @@ impl BlockChain {
         let grandparent_hash_of_new_block = parent_details_of_new_block.parent;
         let prev_best_hash = self.best_block_hash();
 
-        if parent_details_of_new_block.total_score + new_header.score() > self.best_proposal_block_detail().total_score
+        if self.is_new_header_eligible_to_be_best(&new_header)
             && engine.can_change_canon_chain(parent_hash_of_new_block, grandparent_hash_of_new_block, prev_best_hash)
         {
             cinfo!(

core/src/blockchain/extras.rs

@@ -17,7 +17,7 @@
 use crate::db::Key;
 use crate::types::TransactionId;
 use ctypes::{BlockHash, BlockNumber, Tracker, TxHash};
-use primitives::{H256, H264, U256};
+use primitives::{H256, H264};
 use std::ops::{Add, AddAssign, Deref, Sub, SubAssign};
 
 /// Represents index of extra data in database
@@ -93,10 +93,10 @@ impl Key<TransactionAddresses> for Tracker {
 /// Familial details concerning a block
 #[derive(Debug, Clone, RlpEncodable, RlpDecodable)]
 pub struct BlockDetails {
+    /// Block view
+    pub view: u64,
     /// Block number
     pub number: BlockNumber,
-    /// Total score of the block and all its parents
-    pub total_score: U256,
     /// Parent block hash
     pub parent: BlockHash,
 }

core/src/blockchain/headerchain.rs

@@ -72,7 +72,7 @@ impl HeaderChain {
 
                 let details = BlockDetails {
                     number: genesis.number(),
-                    total_score: genesis.score(),
+                    view: genesis.view(),
                     parent: genesis.parent_hash(),
                 };
 
@@ -134,7 +134,7 @@ impl HeaderChain {
         let mut new_details = HashMap::new();
         new_details.insert(hash, BlockDetails {
             number: header.number(),
-            total_score: 0.into(),
+            view: header.view(),
             parent: header.parent_hash(),
         });
 
@@ -252,12 +252,11 @@ impl HeaderChain {
     /// Uses the given parent details or attempts to load them from the database.
     fn new_detail_entries(&self, header: &HeaderView<'_>) -> HashMap<BlockHash, BlockDetails> {
         let parent_hash = header.parent_hash();
-        let parent_details = self.block_details(&parent_hash).expect("Invalid parent hash");
 
         // create current block details.
         let details = BlockDetails {
             number: header.number(),
-            total_score: parent_details.total_score + header.score(),
+            view: header.view(),
             parent: parent_hash,
         };
 
@@ -267,14 +266,22 @@ impl HeaderChain {
         block_details
     }
 
+    /// Compare the number and the view of current block with these of best block
+    fn is_new_header_eligible_to_be_best(&self, new_header: &HeaderView<'_>) -> bool {
+        let best_proposal_block_hash = self.best_header_hash();
+        let best_proposal_block_detail =
+            self.block_details(&best_proposal_block_hash).expect("Best proposal block always exists");
+
+        (new_header.number(), best_proposal_block_detail.view) > (best_proposal_block_detail.number, new_header.view())
+    }
+
     /// Calculate how best block is changed
     fn best_header_changed(&self, new_header: &HeaderView<'_>, engine: &dyn CodeChainEngine) -> BestHeaderChanged {
         let parent_hash_of_new_header = new_header.parent_hash();
         let parent_details_of_new_header = self.block_details(&parent_hash_of_new_header).expect("Invalid parent hash");
         let grandparent_hash_of_new_header = parent_details_of_new_header.parent;
         let prev_best_hash = self.best_header_hash();
-        let is_new_best = parent_details_of_new_header.total_score + new_header.score()
-            > self.best_proposal_header_detail().total_score
+        let is_new_best = self.is_new_header_eligible_to_be_best(new_header)
             && engine.can_change_canon_chain(parent_hash_of_new_header, grandparent_hash_of_new_header, prev_best_hash);
 
         if is_new_best {
@@ -364,10 +371,6 @@ impl HeaderChain {
     pub fn best_proposal_header(&self) -> encoded::Header {
         self.block_header_data(&self.best_proposal_header_hash()).expect("Highest header always exists")
     }
-
-    pub fn best_proposal_header_detail(&self) -> BlockDetails {
-        self.block_details(&self.best_proposal_header_hash()).expect("Best Proposal header always exists")
-    }
 }
 
 /// Interface for querying blocks by hash and by number.

core/src/codechain_machine.rs

@@ -78,12 +78,6 @@ impl CodeChainMachine {
         Ok(())
     }
 
-    /// Populate a header's fields based on its parent's header.
-    /// Usually implements the chain scoring rule based on weight.
-    pub fn populate_from_parent(&self, header: &mut Header, parent: &Header) {
-        header.set_score(*parent.score());
-    }
-
     pub fn min_cost(params: &CommonParams, action: &Action) -> u64 {
         match action {
             Action::Pay {

core/src/encoded.rs

@@ -29,7 +29,7 @@ use crate::views;
 use ccrypto::blake256;
 use ckey::Address;
 use ctypes::{BlockHash, BlockNumber, Header as FullHeader, TxHash};
-use primitives::{H256, U256};
+use primitives::H256;
 use rlp::Rlp;
 
 /// Owning header view.
@@ -99,11 +99,6 @@ impl Header {
         self.view().next_validator_set_hash()
     }
 
-    /// Score of this block
-    pub fn score(&self) -> U256 {
-        self.view().score()
-    }
-
     /// Number of this block.
     pub fn number(&self) -> BlockNumber {
         self.view().number()
@@ -258,11 +253,6 @@ impl Block {
         self.header_view().transactions_root()
     }
 
-    /// Score of this block
-    pub fn score(&self) -> U256 {
-        self.header_view().score()
-    }
-
     /// Number of this block.
     pub fn number(&self) -> BlockNumber {
         self.header_view().number()

core/src/scheme/genesis.rs

@@ -19,14 +19,12 @@ use ccrypto::BLAKE_NULL_RLP;
 use cjson;
 use ckey::{Address, PlatformAddress};
 use ctypes::BlockHash;
-use primitives::{Bytes, H256, U256};
+use primitives::{Bytes, H256};
 
 /// Genesis components.
 pub struct Genesis {
     /// Seal.
     pub seal: Seal,
-    /// Score.
-    pub score: U256,
     /// Author.
     pub author: Address,
     /// Timestamp.
@@ -47,7 +45,6 @@ impl From<cjson::scheme::Genesis> for Genesis {
     fn from(g: cjson::scheme::Genesis) -> Self {
         Genesis {
             seal: From::from(g.seal),
-            score: g.score.into(),
             author: g.author.map_or_else(Address::default, PlatformAddress::into_address),
             timestamp: g.timestamp.map_or(0, Into::into),
             parent_hash: g.parent_hash.map_or_else(H256::zero, Into::into).into(),

core/src/scheme/scheme.rs

@@ -30,7 +30,7 @@ use ctypes::errors::SyntaxError;
 use ctypes::{BlockHash, CommonParams, Header, ShardId};
 use merkle_trie::{TrieFactory, TrieMut};
 use parking_lot::RwLock;
-use primitives::{Bytes, H256, U256};
+use primitives::{Bytes, H256};
 use rlp::{Encodable, Rlp, RlpStream};
 use std::io::Read;
 use std::sync::Arc;
@@ -52,8 +52,6 @@ pub struct Scheme {
     pub parent_hash: BlockHash,
     /// The genesis block's author field.
     pub author: Address,
-    /// The genesis block's score field.
-    pub score: U256,
     /// The genesis block's timestamp field.
     pub timestamp: u64,
     /// Transactions root of the genesis block. Should be BLAKE_NULL_RLP.
@@ -267,7 +265,6 @@ impl Scheme {
         header.set_extra_data(blake256(&self.genesis_params().rlp_bytes()).to_vec());
         header.set_state_root(self.state_root());
         header.set_next_validator_set_hash(BLAKE_NULL_RLP /* This will be calculated from state after https://github.com/CodeChain-io/foundry/issues/142*/);
-        header.set_score(self.score);
         header.set_seal({
             let r = Rlp::new(&self.seal_rlp);
             r.iter().map(|f| f.as_raw().to_vec()).collect()
@@ -308,7 +305,6 @@ fn load_from(s: cjson::scheme::Scheme) -> Result<Scheme, Error> {
         parent_hash: g.parent_hash,
         transactions_root: g.transactions_root,
         author: g.author,
-        score: g.score,
         timestamp: g.timestamp,
         extra_data: g.extra_data,
         seal_rlp,

core/src/tests/helpers.rs

@@ -18,7 +18,7 @@ use crate::scheme::Scheme;
 use crate::transaction::SignedTransaction;
 use cstate::StateDB;
 use ctypes::{BlockHash, Header};
-use primitives::{Bytes, U256};
+use primitives::Bytes;
 use rlp::{self, RlpStream};
 
 pub fn create_test_block(header: &Header) -> Bytes {
@@ -48,7 +48,6 @@ pub fn get_good_dummy_block() -> Bytes {
 pub fn get_good_dummy_block_hash() -> (BlockHash, Bytes) {
     let mut block_header = Header::new();
     let test_scheme = Scheme::new_test();
-    block_header.set_score(U256::from(0x20000));
     block_header.set_timestamp(40);
     block_header.set_number(1);
     block_header.set_parent_hash(test_scheme.genesis_header().hash());

core/src/views/header.rs

@@ -112,4 +112,14 @@ impl<'a> HeaderView<'a> {
         let seal = self.seal();
         seal.into_iter().map(|s| rlp::Rlp::new(&s).data().map(|x| x.to_vec())).collect()
     }
+
+    /// Get view in the seal field of the header.
+    pub fn view(&self) -> u64 {
+        let seal = self.seal();
+        if let Some(rlp_view) = seal.get(1) {
+            Rlp::new(rlp_view.as_slice()).as_val().unwrap()
+        } else {
+            0
+        }
+    }
 }