New logging system.

First step: implementing the architecture. To get back the scope
logging messages, add this line somewhere:
'lg::set_log_domain_severity("general", 2);'.

src/log.cpp

@@ -11,8 +11,97 @@
    See the COPYING file for more details.
 */
 
+#include "SDL.h"
+
 #include "log.hpp"
 
+#include <algorithm>
+#include <cassert>
+#include <iostream>
 #include <sstream>
+#include <vector>
 
-int scope_logger::indent = 0;
+namespace {
+
+struct logd {
+	char const *name_;
+	int severity_;
+};
+
+class null_streambuf : public std::streambuf
+{
+	virtual int overflow(int c) { return std::char_traits< char >::not_eof(c); }
+public:
+	null_streambuf() {}
+};
+
+} // anonymous namespace
+
+static std::vector< logd > log_domains;
+static std::ostream null_ostream(new null_streambuf);
+static int indent = 0;
+
+namespace lg {
+
+logger err("error", 0), warn("warning", 1), info("info", 2);
+log_domain general("general");
+
+log_domain::log_domain(char const *name) : domain_(log_domains.size())
+{
+	logd d = { name, 0 };
+	log_domains.push_back(d);
+}
+
+bool set_log_domain_severity(std::string const &name, int severity)
+{
+	std::vector< logd >::iterator
+		it = log_domains.begin(),
+		it_end = log_domains.end();
+	if (name == "all") {
+		for(; it != it_end; ++it)
+			it->severity_ = severity;
+	} else {
+		for(; it != it_end; ++it)
+			if (name == it->name_) break;
+		if (it == it_end)
+			return false;
+		it->severity_ = severity;
+	}
+	return true;
+}
+
+std::ostream &logger::operator()(log_domain const &domain, bool show_names)
+{
+	logd const &d = log_domains[domain.domain_];
+	if (severity_ > d.severity_)
+		return null_ostream;
+	else {
+		if (show_names)
+			std::cerr << name_ << " " << d.name_ << ": ";
+		return std::cerr;
+	}
+};
+
+scope_logger::scope_logger(log_domain const &domain, const std::string& str)
+	: ticks_(SDL_GetTicks()), str_(str), output_(info(domain, false))
+{
+	do_indent();
+	output_ << "BEGIN: " << str_ << "\n";
+	++indent;
+}
+
+scope_logger::~scope_logger()
+{
+	const int ticks = SDL_GetTicks() - ticks_;
+	--indent;
+	do_indent();
+	output_ << "END: " << str_ << " (took " << ticks << "ms)\n";
+}
+
+void scope_logger::do_indent()
+{
+	for(int i = 0; i != indent; ++i)
+		output_ << "  ";
+}
+
+} // namespace lg

src/log.hpp

@@ -13,56 +13,47 @@
 #ifndef LOG_HPP_INCLUDED
 #define LOG_HPP_INCLUDED
 
-#define LOG_DATA
-
-#ifdef LOG_DATA
-
-#include <iostream>
+#include <iosfwd>
 #include <string>
 
-#include "SDL.h"
+namespace lg {
 
-struct scope_logger
-{
-	scope_logger(const std::string& str) : ticks_(SDL_GetTicks()), str_(str) {
-		do_indent();
-		std::cerr << "BEGIN: " << str_ << "\n";
-		do_indent();
-		++indent;
-	}
+class logger;
 
-	~scope_logger() {
-		const int ticks = SDL_GetTicks() - ticks_;
-		--indent;
-		do_indent();
-		do_indent();
-		std::cerr << "END: " << str_ << " (took " << ticks << "ms)\n";
-	}
-
-	void do_indent()
-	{
-		for(int i = 0; i != indent; ++i)
-			std::cerr << "  ";
-	}
-
-private:
-	int ticks_;
-	std::string str_;
-	static int indent;
+class log_domain {
+	int domain_;
+public:
+	log_domain(char const *name);
+	friend class logger;
 };
 
-#define log_data0(a) std::cerr << a << "\n";
-#define log_data1(a,b) std::cerr << a << " info: " << b << "\n";
-#define log_data2(a,b,c) std::cerr << a << " info: " << b << ", " << c << "\n";
+bool set_log_domain_severity(std::string const &name, int severity);
 
-#define log_scope(a) scope_logger scope_logging_object__(a);
+class logger {
+	char const *name_;
+	int severity_;
+public:
+	logger(char const *name, int severity): name_(name), severity_(severity) {}
+	std::ostream &operator()(log_domain const &domain, bool show_names = true);
+};
 
-#else
-#define log_data0(a)
-#define log_data1(a,b)
-#define log_data2(a,b,c)
+extern logger err, warn, info;
+extern log_domain general;
 
-#define log_scope(a)
-#endif
+class scope_logger
+{
+	int ticks_;
+	std::string str_;
+	std::ostream &output_;
+public:
+	scope_logger(log_domain const &domain, std::string const &str);
+	~scope_logger();
+	void do_indent();
+};
+
+} // namespace lg
+
+#define log_scope(a) lg::scope_logger scope_logging_object__(lg::general, a);
+#define log_scope2(a,b) lg::scope_logger scope_logging_object__(lg::a, b);
 
 #endif