From 72ed186f46a31ec29bb255bfcadfbfd036cce791 Mon Sep 17 00:00:00 2001
From: Nick Johnson <arachnid@notdot.net>
Date: Mon, 20 Nov 2017 16:18:50 +0100
Subject: [PATCH] eth, internal: Implement getModifiedAccountsBy(Hash|Number)
 using trie diffs (#15512)

* eth, internal: Implement  using trie diffs

* eth, internal: Changes in response to review

* eth: More fixes to getModifiedAccountsBy*

* eth: minor polishes on error capitalization
---
 eth/api.go                  | 83 +++++++++++++++++++++++++++++++++++++
 internal/web3ext/web3ext.go | 12 ++++++
 2 files changed, 95 insertions(+)

diff --git a/eth/api.go b/eth/api.go
index e91f51bb99..12448a6a11 100644
--- a/eth/api.go
+++ b/eth/api.go
@@ -636,3 +636,86 @@ func storageRangeAt(st state.Trie, start []byte, maxResult int) StorageRangeResu
 	}
 	return result
 }
+
+// GetModifiedAccountsByumber returns all accounts that have changed between the
+// two blocks specified. A change is defined as a difference in nonce, balance,
+// code hash, or storage hash.
+//
+// With one parameter, returns the list of accounts modified in the specified block.
+func (api *PrivateDebugAPI) GetModifiedAccountsByNumber(startNum uint64, endNum *uint64) ([]common.Address, error) {
+	var startBlock, endBlock *types.Block
+
+	startBlock = api.eth.blockchain.GetBlockByNumber(startNum)
+	if startBlock == nil {
+		return nil, fmt.Errorf("start block %x not found", startNum)
+	}
+
+	if endNum == nil {
+		endBlock = startBlock
+		startBlock = api.eth.blockchain.GetBlockByHash(startBlock.ParentHash())
+		if startBlock == nil {
+			return nil, fmt.Errorf("block %x has no parent", endBlock.Number())
+		}
+	} else {
+		endBlock = api.eth.blockchain.GetBlockByNumber(*endNum)
+		if endBlock == nil {
+			return nil, fmt.Errorf("end block %d not found", *endNum)
+		}
+	}
+	return api.getModifiedAccounts(startBlock, endBlock)
+}
+
+// GetModifiedAccountsByHash returns all accounts that have changed between the
+// two blocks specified. A change is defined as a difference in nonce, balance,
+// code hash, or storage hash.
+//
+// With one parameter, returns the list of accounts modified in the specified block.
+func (api *PrivateDebugAPI) GetModifiedAccountsByHash(startHash common.Hash, endHash *common.Hash) ([]common.Address, error) {
+	var startBlock, endBlock *types.Block
+	startBlock = api.eth.blockchain.GetBlockByHash(startHash)
+	if startBlock == nil {
+		return nil, fmt.Errorf("start block %x not found", startHash)
+	}
+
+	if endHash == nil {
+		endBlock = startBlock
+		startBlock = api.eth.blockchain.GetBlockByHash(startBlock.ParentHash())
+		if startBlock == nil {
+			return nil, fmt.Errorf("block %x has no parent", endBlock.Number())
+		}
+	} else {
+		endBlock = api.eth.blockchain.GetBlockByHash(*endHash)
+		if endBlock == nil {
+			return nil, fmt.Errorf("end block %x not found", *endHash)
+		}
+	}
+	return api.getModifiedAccounts(startBlock, endBlock)
+}
+
+func (api *PrivateDebugAPI) getModifiedAccounts(startBlock, endBlock *types.Block) ([]common.Address, error) {
+	if startBlock.Number().Uint64() >= endBlock.Number().Uint64() {
+		return nil, fmt.Errorf("start block height (%d) must be less than end block height (%d)", startBlock.Number().Uint64(), endBlock.Number().Uint64())
+	}
+
+	oldTrie, err := trie.NewSecure(startBlock.Root(), api.eth.chainDb, 0)
+	if err != nil {
+		return nil, err
+	}
+	newTrie, err := trie.NewSecure(endBlock.Root(), api.eth.chainDb, 0)
+	if err != nil {
+		return nil, err
+	}
+
+	diff, _ := trie.NewDifferenceIterator(oldTrie.NodeIterator([]byte{}), newTrie.NodeIterator([]byte{}))
+	iter := trie.NewIterator(diff)
+
+	var dirty []common.Address
+	for iter.Next() {
+		key := newTrie.GetKey(iter.Key)
+		if key == nil {
+			return nil, fmt.Errorf("no preimage found for hash %x", iter.Key)
+		}
+		dirty = append(dirty, common.BytesToAddress(key))
+	}
+	return dirty, nil
+}
diff --git a/internal/web3ext/web3ext.go b/internal/web3ext/web3ext.go
index 1ae6e2d738..ef0d2b4e6e 100644
--- a/internal/web3ext/web3ext.go
+++ b/internal/web3ext/web3ext.go
@@ -354,6 +354,18 @@ web3._extend({
 			call: 'debug_storageRangeAt',
 			params: 5,
 		}),
+		new web3._extend.Method({
+			name: 'getModifiedAccountsByNumber',
+			call: 'debug_getModifiedAccountsByNumber',
+			params: 2,
+			inputFormatter: [null, null],
+		}),
+		new web3._extend.Method({
+			name: 'getModifiedAccountsByHash',
+			call: 'debug_getModifiedAccountsByHash',
+			params: 2,
+			inputFormatter:[null, null],
+		}),
 	],
 	properties: []
 });