std::thread changed to boost::thread and the emission refactored

README.md

@@ -212,8 +212,8 @@ disabled. To enable it use `--enable-emission-monitor` flag, e.g.,
 xmrblocks --enable-emission-monitor 
 ```
 
-This flag will enable emission monitoring thread. When first started, the thread
- will scan entire blockchain, and calculate the emission based on each block.
+This flag will enable emission monitoring thread. When started, the thread
+ will initially scan the entire blockchain, and calculate the cumulative emission based on each block.
 Since it is a separate thread, the explorer will work as usual during this time. 
 Every 10000 blocks, the thread will save current emission in a file, by default, 
  in `~/.bitmonero/lmdb/emission_amount.txt`. This file is used so that we don't
@@ -221,15 +221,16 @@ Every 10000 blocks, the thread will save current emission in a file, by default,
  explorer restarts, the thread will first check if `~/.bitmonero/lmdb/emission_amount.txt`
  is present, read its values, and continue from there if possible. Subsequently, only the initial
  use of the tread is time consuming. Once the thread scans the entire blockchain, it updates
- the emission with new blocks as they come.
+ the emission amount using new blocks as they come.
  
  When the emission monitor is enabled, information about current emission of coinbase and fees is 
- displied on the front page, e.g., :
+ displayed on the front page, e.g., :
  
 ```
 Monero emission (fees) is 14485540.430 (52545.373) as of 1313448 block
 ```
  
+To disable the monitor, simply restart the explorer without `--enable-emission-monitor` flag. 
     
 ## Enable SSL (https)
 

main.cpp

@@ -17,7 +17,8 @@ namespace myxmr
 {
 struct jsonresponse: crow::response
 {
-    jsonresponse(const nlohmann::json& _body) : crow::response {_body.dump()}
+    jsonresponse(const nlohmann::json& _body)
+            : crow::response {_body.dump()}
     {
         add_header("Access-Control-Allow-Origin", "*");
         add_header("Access-Control-Allow-Headers", "Content-Type");
@@ -26,21 +27,9 @@ struct jsonresponse: crow::response
 };
 }
 
-class ExitHandler
+int
+main(int ac, const char* av[])
 {
-public:
-    void exit() { exitHandler(0); }
-    static void exitHandler(int) { s_shouldExit = true; }
-    bool shouldExit() const { return s_shouldExit; }
-
-private:
-    static bool s_shouldExit;
-};
-
-bool ExitHandler::s_shouldExit = false;
-
-int main(int ac, const char* av[]) {
-
     // get command line options
     xmreg::CmdLineOptions opts {ac, av};
 
@@ -185,12 +174,8 @@ int main(int ac, const char* av[]) {
                 = testnet;
         xmreg::CurrentBlockchainStatus::deamon_url
                 = deamon_url;
-
-        if (!xmreg::CurrentBlockchainStatus::init_monero_blockchain())
-        {
-            cerr << "Error accessing blockchain from CurrentBlockchainStatus." << endl;
-            return EXIT_FAILURE;
-        }
+        xmreg::CurrentBlockchainStatus::set_blockchain_variables(
+                &mcore, core_storage);
 
         // launch the status monitoring thread so that it keeps track of blockchain
         // info, e.g., current height. Information from this thread is used
@@ -551,5 +536,16 @@ int main(int ac, const char* av[]) {
     }
 
 
+    if (enable_emission_monitor == true)
+    {
+        // finish Emission monitoring thread in a cotrolled manner.
+        xmreg::CurrentBlockchainStatus::m_thread.interrupt();
+        xmreg::CurrentBlockchainStatus::m_thread.join();
+
+        cout << "Emission monitoring thread joined." << endl;
+    }
+
+    cout << "The explorer is terminating." << endl;
+
     return EXIT_SUCCESS;
 }

src/CurrentBlockchainStatus.cpp

@@ -11,27 +11,12 @@ using namespace std;
 
 
 
-bool
-CurrentBlockchainStatus::init_monero_blockchain()
+void
+CurrentBlockchainStatus::set_blockchain_variables(MicroCore* _mcore,
+                                                  Blockchain* _core_storage)
 {
-    // set  monero log output level
-    uint32_t log_level = 0;
-    mlog_configure(mlog_get_default_log_path(""), true);
-
-    mcore = unique_ptr<xmreg::MicroCore>(new xmreg::MicroCore{});
-
-    // initialize the core using the blockchain path
-    if (!mcore->init(blockchain_path.string()))
-    {
-        cerr << "Error accessing blockchain." << endl;
-        return false;
-    }
-
-    // get the high level Blockchain object to interact
-    // with the blockchain lmdb database
-    core_storage = &(mcore->get_core());
-
-    return true;
+    mcore = _mcore;
+    core_storage =_core_storage;
 }
 
 
@@ -62,31 +47,50 @@ CurrentBlockchainStatus::start_monitor_blockchain_thread()
 
     if (!is_running)
     {
-        m_thread = std::thread{[]()
+        m_thread = boost::thread{[]()
            {
-               while (true)
+               try
                {
-                   Emission current_emission = total_emission_atomic;
-
-                   current_height = core_storage->get_current_blockchain_height();
-
-                   update_current_emission_amount();
-
-                   save_current_emission_amount();
-
-                   if (current_emission.blk_no < current_height - blockchain_chunk_size)
+                   while (true)
                    {
-                       std::this_thread::sleep_for(std::chrono::seconds(1));
-                   }
-                   else
-                   {
-                       std::this_thread::sleep_for(std::chrono::seconds(60));
-                   }
+                       Emission current_emission = total_emission_atomic;
+
+                       current_height = core_storage->get_current_blockchain_height();
+
+                       // scan 10000 blocks for emissiom or if we are at the top of
+                       // the blockchain, only few top blocks
+                       update_current_emission_amount();
+
+                       cout << "current emission: " << string(current_emission) << endl;
+
+                       save_current_emission_amount();
+
+                       if (current_emission.blk_no < current_height - blockchain_chunk_size)
+                       {
+                           // while we scan the blockchain from scrach, every 10000
+                           // blocks take 1 second break
+                           boost::this_thread::sleep_for(boost::chrono::seconds(1));
+                       }
+                       else
+                       {
+                           // when we reach top of the blockchain, update
+                           // the emission amount every minute.
+                           boost::this_thread::sleep_for(boost::chrono::seconds(60));
+                       }
+
+                   } // while (true)
                }
-           }};
+               catch (boost::thread_interrupted&)
+               {
+                   cout << "Emission monitoring thread interrupted." << endl;
+                   return;
+               }
+
+           }}; //  m_thread = boost::thread{[]()
 
         is_running = true;
-    }
+
+    } //  if (!is_running)
 }
 
 
@@ -117,8 +121,6 @@ CurrentBlockchainStatus::update_current_emission_amount()
     current_emission.blk_no    = emission_calculated.blk_no;
 
     total_emission_atomic = current_emission;
-
-    cout << "total emission: " << string(current_emission) << endl;
 }
 
 CurrentBlockchainStatus::Emission
@@ -311,11 +313,10 @@ atomic<uint64_t> CurrentBlockchainStatus::current_height {0};
 
 atomic<CurrentBlockchainStatus::Emission> CurrentBlockchainStatus::total_emission_atomic;
 
-std::thread      CurrentBlockchainStatus::m_thread;
+boost::thread      CurrentBlockchainStatus::m_thread;
 
 atomic<bool>     CurrentBlockchainStatus::is_running {false};
 
-cryptonote::Blockchain*       CurrentBlockchainStatus::core_storage;
-unique_ptr<xmreg::MicroCore>  CurrentBlockchainStatus::mcore;
-
+Blockchain*       CurrentBlockchainStatus::core_storage {nullptr};
+xmreg::MicroCore*  CurrentBlockchainStatus::mcore {nullptr};
 }

src/CurrentBlockchainStatus.h

@@ -72,20 +72,20 @@ struct CurrentBlockchainStatus
     static atomic<Emission> total_emission_atomic;
 
 
-    static std::thread m_thread;
+    static boost::thread m_thread;
 
     static atomic<bool> is_running;
 
     // make object for accessing the blockchain here
-    static unique_ptr<xmreg::MicroCore> mcore;
-
-    static cryptonote::Blockchain *core_storage;
+    static MicroCore* mcore;
+    static Blockchain* core_storage;
 
     static void
     start_monitor_blockchain_thread();
 
-    static bool
-    init_monero_blockchain();
+    static void
+    set_blockchain_variables(MicroCore* _mcore,
+                             Blockchain* _core_storage);
 
     static void
     update_current_emission_amount();

src/MicroCore.cpp

@@ -327,6 +327,7 @@ MicroCore::get_blk_timestamp(uint64_t blk_height)
  */
 MicroCore::~MicroCore()
 {
+    m_blockchain_storage.get_db().close();
     delete &m_blockchain_storage.get_db();
 }