Redid the readRandomRecords function in DBRecordArray class, plus other small fixes and changes

The previous implementation was confusing and hard to understand, IMHO,
and needlessly complex. I also think this new approach should be faster
in practice due to collating the calls to the DB better and due to use
of MultiGet.

Also in this commit: Added ability for bench/test threads to use the
Log(), and other small fixes and nits.

Author: cculianu

src/App.cpp

@@ -672,6 +672,7 @@ void App::parseArgs()
             // custom hack used only for test/bench mode to enable/disable debug output in test mode from CLI args
             static std::once_flag once;
             std::call_once(once, [&] {
+                logger()->setDirectMode(true); // ensures any benches or tests that spawn threads that use Log(), etc, will lead to printed output
                 if (auto found = parser.optionNames(); const auto dbgct = (found.count("d") + found.count("debug"))) {
                     if (dbgct) options->verboseDebug = true;
                     if (dbgct > 1) options->verboseTrace = true;
@@ -717,11 +718,11 @@ void App::parseArgs()
             }
         }
         if (setCtr)
-            std::exit(0);
+            std::exit(EXIT_SUCCESS);
     } catch (const std::exception & e) {
         // bench or test execution failed with an exception
         Error(Log::Color::Magenta) << "Caught exception: " << e.what();
-        std::exit(1);
+        std::exit(EXIT_FAILURE);
     }
 
     const auto checkSupportsSsl = [] {

src/Logger.cpp

@@ -50,7 +50,7 @@ namespace {
 
 Logger::Logger(QObject *parent) : QObject(parent)
 {
-    connect(this, &Logger::log, this, [this](int level, const QString &line){
+    connGotLine = connect(this, &Logger::log, this, [this](int level, const QString &line){
         // we do it in a closure because in this c'tor gotLine isn't defined yet (pure virtual)
         gotLine(level, line);
     });
@@ -83,6 +83,19 @@ bool ConsoleLogger::calcIsATty(bool stdOut)
     return false;
 }
 
+bool ConsoleLogger::setDirectMode(bool b) /* override */
+{
+    if (b != isDirectMode()) {
+        disconnect(connGotLine);
+        connGotLine = connect(this, &Logger::log, this, [this](int level, const QString &line) { gotLine(level, line); },
+                              b ? Qt::DirectConnection : Qt::AutoConnection);
+        directMode = b;
+    }
+    return true;
+}
+
+bool ConsoleLogger::isDirectMode() const /* override */ { return directMode; }
+
 void ConsoleLogger::gotLine(int level, const QString &l)
 {
     auto * const strm = stdOut ? stdout : stderr;

src/Logger.h

@@ -36,11 +36,18 @@ class Logger : public QObject
     /// returns true if the logger is logging to a tty (and thus supports ANSI color codes, etc)
     virtual bool isaTTY() const { return false; }
 
+    /// Set "direct" mode on or off. Default is for it to be off. In direct mode the log() signal is connected
+    /// via Qt::DirectConnection to gotLine(). Returns false on error, true on success.
+    virtual bool setDirectMode(bool) { return false; }
+    virtual bool isDirectMode() const { return false;}
+
 signals:
     void log(int level, const QString & line); ///< call this or emit it to log a line
 
 protected:
     virtual void gotLine(int level, const QString &) = 0;
+
+    QMetaObject::Connection connGotLine;
 };
 
 class ConsoleLogger : public Logger
@@ -50,13 +57,17 @@ class ConsoleLogger : public Logger
 
     bool isaTTY() const override { return isATty; }
 
+    bool setDirectMode(bool) override;
+    bool isDirectMode() const override;
+
 protected:
     void gotLine(int level, const QString &) override;
 
 private:
     const bool stdOut;
     const bool isATty;
     static bool calcIsATty(bool stdOut);
+    bool directMode = false;
 };
 
 /// On Windows this just prints to stdout. On Unix, calls syslog()
@@ -67,6 +78,8 @@ class SysLogger : public ConsoleLogger
     SysLogger(QObject *parent = nullptr);
     bool isaTTY() const override { return !opened && ConsoleLogger::isaTTY(); }
 
+    bool setDirectMode(bool) override { return false; }
+
 protected:
     void gotLine(int level, const QString &) override;