From 12335d09c40f26aea948822d299b6f0cc4045650 Mon Sep 17 00:00:00 2001
From: Chalith Desaman <desaman.chalith@gmail.com>
Date: Mon, 30 Nov 2020 22:21:56 +0530
Subject: [PATCH] Skip ledger truncation when full history is enabled (#177)

* Skip ledger truncation when full history is enabled.
* Skip clearing ledger if full history is enabled.
---
 src/ledger.cpp | 32 +++++++++++++++++++-------------
 src/ledger.hpp |  2 +-
 2 files changed, 20 insertions(+), 14 deletions(-)

diff --git a/src/ledger.cpp b/src/ledger.cpp
index 4fabec10..3436a781 100644
--- a/src/ledger.cpp
+++ b/src/ledger.cpp
@@ -197,6 +197,7 @@ namespace ledger
 
                 if (!sync_ctx.target_lcl.empty())
                 {
+                    // If target lcl is genesis lcl, Clear the ledger history and reset target sequence number.
                     if (sync_ctx.target_lcl == GENESIS_LEDGER)
                     {
                         LOG_INFO << "lcl sync: Target is GENESIS. Clearing our history.";
@@ -205,9 +206,10 @@ namespace ledger
                         sync_ctx.target_lcl_seq_no = 0;
                         sync_ctx.is_syncing = false;
                     }
-                    // Check the target lcl seq no. to see whether it's too far ahead. That means no one probably has our
+                    // If full history mode is not enabled check the target lcl seq no
+                    // to see whether it's too far ahead. That means no one probably has our
                     // lcl in their ledgers. So we should clear our entire ledger history before requesting from peers.
-                    else if (current_lcl != GENESIS_LEDGER && sync_ctx.target_lcl_seq_no > (ctx.get_seq_no() + MAX_LEDGER_SEQUENCE))
+                    else if (!conf::cfg.fullhistory && current_lcl != GENESIS_LEDGER && sync_ctx.target_lcl_seq_no > (ctx.get_seq_no() + MAX_LEDGER_SEQUENCE))
                     {
                         LOG_INFO << "lcl sync: Target " << sync_ctx.target_lcl.substr(0, 15) << " is too far ahead. Clearing our history.";
                         clear_ledger();
@@ -354,20 +356,24 @@ namespace ledger
      */
     void remove_old_ledgers(const uint64_t led_seq_no)
     {
-        std::map<uint64_t, const std::string>::iterator itr;
-
-        for (itr = ctx.cache.begin();
-             itr != ctx.cache.lower_bound(led_seq_no + 1);
-             itr++)
+        // Remove old ledgers if full history mode is not enabled.
+        if (!conf::cfg.fullhistory)
         {
-            const std::string file_path = conf::ctx.hist_dir + "/" + itr->second + ".lcl";
+            std::map<uint64_t, const std::string>::iterator itr;
 
-            if (util::is_file_exists(file_path))
-                util::remove_file(file_path);
+            for (itr = ctx.cache.begin();
+                 itr != ctx.cache.lower_bound(led_seq_no + 1);
+                 itr++)
+            {
+                const std::string file_path = conf::ctx.hist_dir + "/" + itr->second + ".lcl";
+
+                if (util::is_file_exists(file_path))
+                    util::remove_file(file_path);
+            }
+
+            if (!ctx.cache.empty())
+                ctx.cache.erase(ctx.cache.begin(), ctx.cache.lower_bound(led_seq_no + 1));
         }
-
-        if (!ctx.cache.empty())
-            ctx.cache.erase(ctx.cache.begin(), ctx.cache.lower_bound(led_seq_no + 1));
     }
 
     /**
diff --git a/src/ledger.hpp b/src/ledger.hpp
index b6b7449a..afdc65fc 100644
--- a/src/ledger.hpp
+++ b/src/ledger.hpp
@@ -38,7 +38,7 @@ namespace ledger
         // Map of closed ledgers (lcl string) with sequence number as map key.
         // Contains closed ledgers from oldest to latest - MAX_LEDGER_SEQUENCE.
         // This is loaded when node started and updated throughout consensus.
-        // Deletes ledgers that falls behind MAX_LEDGER_SEQUENCE range.
+        // If full history mode is not enabled, deletes ledgers that falls behind MAX_LEDGER_SEQUENCE range.
         std::map<uint64_t, const std::string> cache;
 
         std::mutex ledger_mutex;