From fcb5613755b08fcb7ae73a3826b1cdce40e2747f Mon Sep 17 00:00:00 2001
From: Marcos Magueta <maguetamarcos@gmail.com>
Date: Sun, 27 Oct 2024 01:53:18 -0300
Subject: State of the world with Merkle Tree composition of files (#2)

* file state hash calculation with history on replace and insert

* add state transitions with linear hashing

* add test

* format dune files

* nix format

* delete shared flake

* disable fmt check on flake

* add nix formatter to flake shell
---
 shared/librelational_engine/library.cpp | 47 +++++++++++++++++++++++++++++++--
 1 file changed, 45 insertions(+), 2 deletions(-)

(limited to 'shared/librelational_engine/library.cpp')

diff --git a/shared/librelational_engine/library.cpp b/shared/librelational_engine/library.cpp
index 8048486..cab8f93 100644
--- a/shared/librelational_engine/library.cpp
+++ b/shared/librelational_engine/library.cpp
@@ -2,8 +2,51 @@
 #include <merklecpp.h>
 #include <openssl/sha.h>
 #include <iomanip>
+#include <fstream>
+#include <iterator>
+
+#include <sys/stat.h>
+
+std::vector<uint8_t> read_tree(const char* tree_path) {
+    std::ifstream file(tree_path, std::ios::binary);
+    file.unsetf(std::ios::skipws);
+    file.seekg(0, std::ios::end);
+    const std::streampos file_size = file.tellg();
+    file.seekg(0, std::ios::beg);
+    std::vector<uint8_t> v;
+    v.reserve(file_size);
+    v.insert(v.begin(), std::istream_iterator<uint8_t>(file), std::istream_iterator<uint8_t>());
+    return v;
+}
+
+void write_tree(const char* tree_path, const std::vector<uint8_t>& serialized_tree) {
+    std::ofstream out(tree_path, std::ios::out | std::ios::binary);
+    out.write(reinterpret_cast<const char*>(serialized_tree.data()), serialized_tree.size());
+    out.close();
+}
+
 extern "C" {
 #include "library.h"
+    extern void register_to_merkle(const char* tree_path, const char* computed_hash) {
+        struct stat st;
+        if (stat(tree_path, &st) == 0) {
+            const std::vector<uint8_t> tree_bytes = read_tree(tree_path);
+            merkle::Tree tree;
+            tree.deserialise(tree_bytes);
+            const merkle::Tree::Hash hash(computed_hash);
+            tree.insert(hash);
+            std::vector<uint8_t> target;
+            tree.serialise(target);
+            write_tree(tree_path, target);
+        } else {
+            merkle::Tree::Hash hash(computed_hash);
+            merkle::Tree tree;
+            tree.insert(hash);
+            std::vector<uint8_t> target;
+            tree.serialise(target);
+            write_tree(tree_path, target);
+        }
+    }
     extern void merkle_generate_root(char** hashes, const int n, char* root) {
         merkle::Tree tree;
         for (int i = 0; i < n; i++){
@@ -23,8 +66,8 @@ extern "C" {
             ss << std::hex << std::setw(2) << std::setfill('0') << static_cast<int>(hash[i]);
 
         std::memcpy(computed_hash, ss.str().c_str(), HASH_SIZE);
-        std::cout << "⚙️ COMPUTED HASH: " << computed_hash << std::endl;
+        // std::cout << "⚙️ COMPUTED HASH: " << computed_hash << std::endl;
     }
 
     extern int trash() { return 100; }
-}
\ No newline at end of file
+}
-- 
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