Fix connection issues and add enhancement to the Dashboard (#130)

* Fix connection errors when doing DNS lookup
* Fix connection handling when an error occurs
* Add remote logging feature
* Add algo variant to dashboard

src/log/RemoteLog.cpp

@@ -0,0 +1,93 @@
+/* XMRig
+ * Copyright 2018-     BenDr0id <ben@graef.in>
+ *
+ *   This program is free software: you can redistribute it and/or modify
+ *   it under the terms of the GNU General Public License as published by
+ *   the Free Software Foundation, either version 3 of the License, or
+ *   (at your option) any later version.
+ *
+ *   This program is distributed in the hope that it will be useful,
+ *   but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ *   GNU General Public License for more details.
+ *
+ *   You should have received a copy of the GNU General Public License
+ *   along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+
+#include <sstream>
+#include <regex>
+#include "log/RemoteLog.h"
+
+RemoteLog* RemoteLog::m_self = nullptr;
+
+RemoteLog::RemoteLog(size_t maxRows)
+    : maxRows_(maxRows)
+{
+    m_self = this;
+}
+
+RemoteLog::~RemoteLog()
+{
+    m_self = nullptr;
+}
+
+void RemoteLog::message(int level, const char* fmt, va_list args)
+{
+    time_t now = time(nullptr);
+    tm stime;
+
+#   ifdef _WIN32
+    localtime_s(&stime, &now);
+#   else
+    localtime_r(&now, &stime);
+#   endif
+
+    char *buf = new char[512];
+    int size = snprintf(buf, 23, "[%d-%02d-%02d %02d:%02d:%02d] ",
+                        stime.tm_year + 1900,
+                        stime.tm_mon + 1,
+                        stime.tm_mday,
+                        stime.tm_hour,
+                        stime.tm_min,
+                        stime.tm_sec);
+
+    size = vsnprintf(buf + size, 512 - size - 1, fmt, args) + size;
+    buf[size] = '\n';
+
+    if (rows_.size() == maxRows_) {
+        rows_.pop_front();
+    }
+
+    std::string row = std::regex_replace(std::string(buf, size+1), std::regex("\x1B\\[[0-9;]*[a-zA-Z]"), "");
+
+    rows_.push_back(row);
+}
+
+
+void RemoteLog::text(const char* fmt, va_list args)
+{
+    message(0, fmt, args);
+}
+
+void RemoteLog::flushRows()
+{
+    if (m_self) {
+        m_self->rows_.clear();
+    }
+}
+
+
+std::string RemoteLog::getRows()
+{
+    std::stringstream data;
+
+    if (m_self) {
+        for (std::list<std::string>::iterator it = m_self->rows_.begin(); it != m_self->rows_.end(); it++) {
+            data << it->c_str();
+        }
+    }
+
+    return data.str();
+}