From 5cdc743d491a04ee0446bd757cedb4c7b6bc585f Mon Sep 17 00:00:00 2001
From: Carlo Zancanaro <carlo@pc-4w14-0.cs.usyd.edu.au>
Date: Mon, 9 Jul 2012 17:09:49 +1000
Subject: Cleaning up a bit of code around the place.

 - Especially making logging a bit nicer.
---
 impl/Log.hpp | 71 +++++++++++++++++++++++++++++++++++-------------------------
 1 file changed, 42 insertions(+), 29 deletions(-)

(limited to 'impl/Log.hpp')

diff --git a/impl/Log.hpp b/impl/Log.hpp
index 1e340c7..0f12fec 100644
--- a/impl/Log.hpp
+++ b/impl/Log.hpp
@@ -1,50 +1,63 @@
 #ifndef LOG_HPP
 #define LOG_HPP
 
+// could not be hackier, but C++ is annoying
+#define protected public
+#include <streambuf>
+#undef protected
+
 #include <string>
-#include <ostream>
+#include <iostream>
 #include <map>
 
 namespace log {
 
-  struct Logger {
-    Logger(std::ostream& stream, const std::string& name)
-      : _stream(stream),
-        _name(name),
-        _enabled(false) {}
+  struct LoggerBuffer : public std::streambuf {
+    LoggerBuffer(std::streambuf* buffer, const std::string& name)
+      : _buffer(buffer),
+        _prefix(name + " :- "),
+        _prefix_next(true) { }
+
+    int_type overflow(int_type c=EOF) {
+      if (_prefix_next) {
+        _buffer->sputn(_prefix.c_str(), _prefix.length());
+        _prefix_next = false;
+      }
+      if (c == '\n') {
+        _prefix_next = true;
+      }
+      return _buffer->overflow(c);
+    }
+  private:
+    std::streambuf* _buffer;
+    std::string _prefix;
+    bool _prefix_next;
+  };
+
+  struct Logger : public std::ostream {
+    Logger(std::streambuf* buffer, const std::string& name)
+      : std::ostream(NULL),
+        _buffer(buffer, name) { }
 
     bool enabled() const {
-      return _enabled;
+      return rdbuf() != NULL;
     }
 
     bool enabled(bool v) {
-      bool ret = _enabled;
-      _enabled = v;
+      bool ret = enabled();
+      rdbuf(v ? &_buffer : NULL);
       return ret;
     }
 
-    template<typename T>
-    friend Logger& operator<<(Logger&, const T&);
-    
-    private:
-    std::ostream& _stream;
-    std::string _name;
-    bool _enabled;
+  private:
+    LoggerBuffer _buffer;
   };
 
-  template<typename T>
-  Logger& operator<<(Logger& logger, const T& obj) {
-    if (logger._enabled) {
-      logger._stream << logger._name << " :- " << obj << std::endl;
-    }
-    return logger;
-  }
-
-  Logger info(std::cout, "info");
-  Logger trace(std::cerr, "trace");
-  Logger strategy(std::cerr, "strategy");
-  Logger fixpoint(std::cerr, "fixpoint");
-  Logger debug(std::cerr, "debug");
+  Logger info(std::cout.rdbuf(), "info");
+  Logger trace(std::cerr.rdbuf(), "trace");
+  Logger strategy(std::cerr.rdbuf(), "strategy");
+  Logger fixpoint(std::cerr.rdbuf(), "fixpoint");
+  Logger debug(std::cerr.rdbuf(), "debug");
 
 }
 
-- 
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