Add a persistent screen showing basic node metrics

The screen is implemented using ANSI Escape sequences.

Closes #1331

src/metrics.cpp

@@ -0,0 +1,104 @@
+// Copyright (c) 2016 The Zcash developers
+// Distributed under the MIT software license, see the accompanying
+// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+#include "metrics.h"
+
+#include "chainparams.h"
+#include "util.h"
+#include "utiltime.h"
+
+#include <boost/thread.hpp>
+
+AtomicCounter transactionsValidated;
+AtomicCounter ehSolverRuns;
+AtomicCounter minedBlocks;
+
+void ThreadShowMetricsScreen()
+{
+    // Make this thread recognisable as the metrics screen thread
+    RenameThread("zcash-metrics-screen");
+
+    // Clear screen
+    std::cout << "\e[2J";
+
+    // Print art
+    std::cout << METRICS_ART << std::endl;
+    std::cout << std::endl;
+
+    // Thank you text
+    std::cout << OFFSET << "Thank you for running a Zcash node!" << std::endl;
+    std::cout << OFFSET << "By running this node, you're contributing to the social good :)" << std::endl;
+    std::cout << std::endl;
+
+    // Miner status
+    bool mining = GetBoolArg("-gen", false);
+    if (mining) {
+        int nThreads = GetArg("-genproclimit", 1);
+        if (nThreads < 0) {
+            // In regtest threads defaults to 1
+            if (Params().DefaultMinerThreads())
+                nThreads = Params().DefaultMinerThreads();
+            else
+                nThreads = boost::thread::hardware_concurrency();
+        }
+        std::cout << OFFSET << "You are running " << nThreads << " mining threads." << std::endl;
+    } else {
+        std::cout << OFFSET << "You are currently not mining." << std::endl;
+        std::cout << OFFSET << "To enable mining, add 'gen=1' to your zcash.conf and restart." << std::endl;
+    }
+    std::cout << std::endl;
+
+    // Count uptime
+    int64_t nStart = GetTime();
+
+    while (true) {
+        int lines = 4;
+
+        // Erase below current position
+        std::cout << "\e[J";
+
+        // Calculate uptime
+        int64_t uptime = GetTime() - nStart;
+        int days = uptime / (24 * 60 * 60);
+        int hours = (uptime - (days * 24 * 60 * 60)) / (60 * 60);
+        int minutes = (uptime - (((days * 24) + hours) * 60 * 60)) / 60;
+        int seconds = uptime - (((((days * 24) + hours) * 60) + minutes) * 60);
+
+        // Display uptime
+        std::cout << OFFSET << "Since starting this node ";
+        if (days > 0) {
+            std::cout << days << " days, ";
+        }
+        if (hours > 0) {
+            std::cout << hours << " hours, ";
+        }
+        if (minutes > 0) {
+            std::cout << minutes << " minutes, ";
+        }
+        std::cout << seconds << " seconds ago:" << std::endl;
+
+        std::cout << OFFSET << "- You have validated " << transactionsValidated.get() << " transactions." << std::endl;
+
+        if (mining) {
+            std::cout << OFFSET << "- You have completed " << ehSolverRuns.get() << " Equihash solver runs." << std::endl;
+            lines++;
+
+            int mined = minedBlocks.get();
+            if (mined > 0) {
+                std::cout << OFFSET << "- You have mined " << mined << " blocks!" << std::endl;
+                lines++;
+            }
+        }
+
+        // Explain how to exit
+        std::cout << std::endl;
+        std::cout << "[Hit Ctrl+C to exit] [Set 'showmetrics=0' to hide]" << std::endl;;
+
+        boost::this_thread::interruption_point();
+        MilliSleep(1000);
+
+        // Return to the top of the updating section
+        std::cout << "\e[" << lines << "A";
+    }
+}