Mark one-parameter constructors as explicit & use override where possible

This commit marks (hopefully) ever one-parameter constructor as explicit.

It also uses override in (hopefully) all circumstances where a virtual
method is overridden.

There are a very few other minor changes - most of them were necessary
to get everything to compile (like one additional constructor). In one
case I changed an implicit operation to an explicit string conversion -
I think the automatically chosen conversion was much more convoluted.

This took longer than I want to admit but not as long as I feared :)

src/logging/Component.h

@@ -37,7 +37,7 @@ public:
 	/**
 	 * Destructor.
 	 */
-	~Component();
+	~Component() override;
 
 	/**
 	 * Initialization function. This function has to be called before any

src/logging/Tag.h

@@ -98,14 +98,14 @@ protected:
 	 * @param subtype The sub type, which is left to an writer for
 	 * interpretation. By default it's set to zero.
 	 */
-	Tag(type_t type, subtype_t subtype = 0);
+	explicit Tag(type_t type, subtype_t subtype = 0);
 
 	/**
 	 * Constructor.
 	 *
 	 * @param val An enum value of script type \c Log::Writer.
 	 */
-	Tag(EnumVal* val) : ::Tag(val) {}
+	explicit Tag(EnumVal* val) : ::Tag(val) {}
 };
 
 }

src/logging/WriterBackend.h

@@ -47,7 +47,7 @@ public:
 	/**
 	 * Destructor.
 	 */
-	virtual ~WriterBackend();
+	~WriterBackend() override;
 
 	/**
 	 * A struct passing information to the writer at initialization time.

src/logging/writers/ascii/Ascii.h

@@ -14,8 +14,8 @@ namespace logging { namespace writer {
 
 class Ascii : public WriterBackend {
 public:
-	Ascii(WriterFrontend* frontend);
-	~Ascii();
+	explicit Ascii(WriterFrontend* frontend);
+	~Ascii() override;
 
 	static string LogExt();
 
@@ -23,19 +23,19 @@ public:
 		{ return new Ascii(frontend); }
 
 protected:
-	virtual bool DoInit(const WriterInfo& info, int num_fields,
-			    const threading::Field* const* fields);
-	virtual bool DoWrite(int num_fields, const threading::Field* const* fields,
-			     threading::Value** vals);
-	virtual bool DoSetBuf(bool enabled);
-	virtual bool DoRotate(const char* rotated_path, double open,
-			      double close, bool terminating);
-	virtual bool DoFlush(double network_time);
-	virtual bool DoFinish(double network_time);
-	virtual bool DoHeartbeat(double network_time, double current_time);
+	bool DoInit(const WriterInfo& info, int num_fields,
+			    const threading::Field* const* fields) override;
+	bool DoWrite(int num_fields, const threading::Field* const* fields,
+			     threading::Value** vals) override;
+	bool DoSetBuf(bool enabled) override;
+	bool DoRotate(const char* rotated_path, double open,
+			      double close, bool terminating) override;
+	bool DoFlush(double network_time) override;
+	bool DoFinish(double network_time) override;
+	bool DoHeartbeat(double network_time, double current_time) override;
 
 private:
-	bool IsSpecial(string path) 	{ return path.find("/dev/") == 0; }
+	bool IsSpecial(const string &path) 	{ return path.find("/dev/") == 0; }
 	bool WriteHeader(const string& path);
 	bool WriteHeaderField(const string& key, const string& value);
 	void CloseFile(double t);

src/logging/writers/none/None.h

@@ -11,24 +11,23 @@ namespace logging { namespace writer {
 
 class None : public WriterBackend {
 public:
-	None(WriterFrontend* frontend) : WriterBackend(frontend)	{}
-	~None()	{};
+	explicit None(WriterFrontend* frontend) : WriterBackend(frontend)	{}
+	~None() override {};
 
 	static WriterBackend* Instantiate(WriterFrontend* frontend)
 		{ return new None(frontend); }
 
 protected:
-	virtual bool DoInit(const WriterInfo& info, int num_fields,
-			    const threading::Field* const * fields);
-
-	virtual bool DoWrite(int num_fields, const threading::Field* const* fields,
-			     threading::Value** vals)	{ return true; }
-	virtual bool DoSetBuf(bool enabled)	{ return true; }
-	virtual bool DoRotate(const char* rotated_path, double open,
-			      double close, bool terminating);
-	virtual bool DoFlush(double network_time)	{ return true; }
-	virtual bool DoFinish(double network_time)	{ return true; }
-	virtual bool DoHeartbeat(double network_time, double current_time)	{ return true; }
+	bool DoInit(const WriterInfo& info, int num_fields,
+			    const threading::Field* const * fields) override;
+	bool DoWrite(int num_fields, const threading::Field* const* fields,
+			     threading::Value** vals) override { return true; }
+	bool DoSetBuf(bool enabled) override { return true; }
+	bool DoRotate(const char* rotated_path, double open,
+			      double close, bool terminating) override;
+	bool DoFlush(double network_time) override { return true; }
+	bool DoFinish(double network_time) override { return true; }
+	bool DoHeartbeat(double network_time, double current_time) override { return true; }
 };
 
 }

src/logging/writers/sqlite/Plugin.cc

@@ -10,7 +10,7 @@ namespace Bro_SQLiteWriter {
 
 class Plugin : public plugin::Plugin {
 public:
-	plugin::Configuration Configure()
+	plugin::Configuration Configure() override
 		{
 		AddComponent(new ::logging::Component("SQLite", ::logging::writer::SQLite::Instantiate));
 

src/logging/writers/sqlite/SQLite.h

@@ -15,23 +15,23 @@ namespace logging { namespace writer {
 
 class SQLite : public WriterBackend {
 public:
-	SQLite(WriterFrontend* frontend);
-	~SQLite();
+	explicit SQLite(WriterFrontend* frontend);
+	~SQLite() override;
 
 	static WriterBackend* Instantiate(WriterFrontend* frontend)
 		{ return new SQLite(frontend); }
 
 protected:
-	virtual bool DoInit(const WriterInfo& info, int arg_num_fields,
-			    const threading::Field* const* arg_fields);
-	virtual bool DoWrite(int num_fields, const threading::Field* const* fields,
-			     threading::Value** vals);
-	virtual bool DoSetBuf(bool enabled) { return true; }
-	virtual bool DoRotate(const char* rotated_path, double open,
-			      double close, bool terminating);
-	virtual bool DoFlush(double network_time)	{ return true; }
-	virtual bool DoFinish(double network_time)	{ return true; }
-	virtual bool DoHeartbeat(double network_time, double current_time)	{ return true; }
+	bool DoInit(const WriterInfo& info, int arg_num_fields,
+			    const threading::Field* const* arg_fields) override;
+	bool DoWrite(int num_fields, const threading::Field* const* fields,
+			     threading::Value** vals) override;
+	bool DoSetBuf(bool enabled) override { return true; }
+	bool DoRotate(const char* rotated_path, double open,
+			      double close, bool terminating) override;
+	bool DoFlush(double network_time) override { return true; }
+	bool DoFinish(double network_time) override { return true; }
+	bool DoHeartbeat(double network_time, double current_time) override { return true; }
 
 private:
 	bool checkError(int code);