2008-04-26 Tatsuhiro Tsujikawa <tujikawa at rednoah dot com>

	Added StringFormat class, which internally calls vasprintf.
	operator<< is defined for this class, so it can be used with iostream
	classes nicely. SimpleLogger and following functions are rewritten
	using StringFormat class.
	Besides, now Logger class's methods are non-const, many classes
	that has a const Logger* as a member variable are modified to remove
	const qualifier from the variable declaration.
	* src/HelpItemFactory.cc
	* src/Request.cc
	* src/SimpleLogger.cc
	* src/StringFormat.cc
	* src/StringFormat.h
	* src/Util.cc
	* src/option_processing.cc
	* src/version_usage.cc
	* test/StringFormatTest.cc
	* src/*.h: The classes that has const Logger* as a member variable.

53 files changed, 277 insertions, 140 deletions

diff --git a/src/AbstractBtMessage.h b/src/AbstractBtMessage.h
index 16dfc3c2..67858565 100644
--- a/src/AbstractBtMessage.h
+++ b/src/AbstractBtMessage.h
@@ -76,7 +76,7 @@ protected:
 
   std::deque<SharedHandle<BtEventListener> > listeners;
 
-  const Logger* logger;
+  Logger* logger;
 public:
   AbstractBtMessage();
 
diff --git a/src/AbstractDiskWriter.h b/src/AbstractDiskWriter.h
index 9f7704cc..5067bc62 100644
--- a/src/AbstractDiskWriter.h
+++ b/src/AbstractDiskWriter.h
@@ -46,7 +46,7 @@ class AbstractDiskWriter : public DiskWriter {
 protected:
   std::string filename;
   int fd;
-  const Logger* logger;
+  Logger* logger;
 
   void createFile(const std::string& filename, int addFlags = 0);
 
diff --git a/src/BtDependency.h b/src/BtDependency.h
index dcbfad51..7edc8c15 100644
--- a/src/BtDependency.h
+++ b/src/BtDependency.h
@@ -49,7 +49,7 @@ private:
   WeakHandle<RequestGroup> _dependant;
   SharedHandle<RequestGroup> _dependee;
   const Option* _option;
-  const Logger* _logger;
+  Logger* _logger;
 public:
   BtDependency(const WeakHandle<RequestGroup>& dependant,
 	       const SharedHandle<RequestGroup>& dependee,
diff --git a/src/BtLeecherStateChoke.h b/src/BtLeecherStateChoke.h
index d898775b..80070143 100644
--- a/src/BtLeecherStateChoke.h
+++ b/src/BtLeecherStateChoke.h
@@ -51,7 +51,7 @@ private:
 
   Time _lastRound;
 
-  const Logger* _logger;
+  Logger* _logger;
 
   void plannedOptimisticUnchoke(std::deque<Peer*>& peers);
 
diff --git a/src/BtSeederStateChoke.h b/src/BtSeederStateChoke.h
index 8255dcd8..79b06075 100644
--- a/src/BtSeederStateChoke.h
+++ b/src/BtSeederStateChoke.h
@@ -54,7 +54,7 @@ private:
 
   Time _lastRound;
 
-  const Logger* _logger;
+  Logger* _logger;
 
   void unchoke(std::deque<Peer*>& peers);
 public:
diff --git a/src/BtSetup.h b/src/BtSetup.h
index 3617e970..ed113438 100644
--- a/src/BtSetup.h
+++ b/src/BtSetup.h
@@ -48,7 +48,7 @@ class Command;
 
 class BtSetup {
 private:
-  const Logger* _logger;
+  Logger* _logger;
 public:
   BtSetup();
 
diff --git a/src/Command.h b/src/Command.h
index f2f24282..0aa77504 100644
--- a/src/Command.h
+++ b/src/Command.h
@@ -60,7 +60,7 @@ private:
   STATUS status;
 protected:
   int32_t cuid;
-  const Logger* logger;
+  Logger* logger;
 public:
   Command(int32_t cuid);
 
diff --git a/src/DHTAbstractTask.h b/src/DHTAbstractTask.h
index c0016a8e..82500763 100644
--- a/src/DHTAbstractTask.h
+++ b/src/DHTAbstractTask.h
@@ -54,7 +54,7 @@ class DHTAbstractTask:public DHTTask {
 protected:
   bool _finished;
   
-  const Logger* _logger;
+  Logger* _logger;
   
   SharedHandle<DHTNode> _localNode;
 
diff --git a/src/DHTBucket.h b/src/DHTBucket.h
index adbcee8f..c1b2252c 100644
--- a/src/DHTBucket.h
+++ b/src/DHTBucket.h
@@ -67,7 +67,7 @@ private:
 
   Time _lastUpdated;
 
-  const Logger* _logger;
+  Logger* _logger;
 public:
   DHTBucket(const SharedHandle<DHTNode>& localNode);
 
diff --git a/src/DHTConnectionImpl.h b/src/DHTConnectionImpl.h
index 7e3f94a5..8806d6cd 100644
--- a/src/DHTConnectionImpl.h
+++ b/src/DHTConnectionImpl.h
@@ -48,7 +48,7 @@ class DHTConnectionImpl:public DHTConnection {
 private:
   SharedHandle<SocketCore> _socket;
 
-  const Logger* _logger;
+  Logger* _logger;
 public:
   DHTConnectionImpl();
 
diff --git a/src/DHTMessageDispatcherImpl.h b/src/DHTMessageDispatcherImpl.h
index 9ef29398..d18d04a3 100644
--- a/src/DHTMessageDispatcherImpl.h
+++ b/src/DHTMessageDispatcherImpl.h
@@ -50,7 +50,7 @@ private:
 
   std::deque<SharedHandle<DHTMessageEntry> > _messageQueue;
 
-  const Logger* _logger;
+  Logger* _logger;
 
   void sendMessage(const SharedHandle<DHTMessageEntry>& msg);
 public:
diff --git a/src/DHTMessageFactoryImpl.h b/src/DHTMessageFactoryImpl.h
index dcffcdd1..5f0fc248 100644
--- a/src/DHTMessageFactoryImpl.h
+++ b/src/DHTMessageFactoryImpl.h
@@ -63,7 +63,7 @@ private:
 
   WeakHandle<DHTTokenTracker> _tokenTracker;
 
-  const Logger* _logger;
+  Logger* _logger;
   
   // search node in routingTable. If it is not found, create new one.
   SharedHandle<DHTNode> getRemoteNode(const unsigned char* id, const std::string& ipaddr, uint16_t port) const;
diff --git a/src/DHTMessageReceiver.h b/src/DHTMessageReceiver.h
index f77f3f09..20b2143e 100644
--- a/src/DHTMessageReceiver.h
+++ b/src/DHTMessageReceiver.h
@@ -58,7 +58,7 @@ private:
 
   SharedHandle<DHTRoutingTable> _routingTable;
 
-  const Logger* _logger;
+  Logger* _logger;
 
   SharedHandle<DHTMessage>
   handleUnknownMessage(const unsigned char* data, size_t length,
diff --git a/src/DHTMessageTracker.h b/src/DHTMessageTracker.h
index 9c92b78e..890bcd5c 100644
--- a/src/DHTMessageTracker.h
+++ b/src/DHTMessageTracker.h
@@ -59,7 +59,7 @@ private:
 
   SharedHandle<DHTMessageFactory> _factory;
 
-  const Logger* _logger;
+  Logger* _logger;
 public:
   DHTMessageTracker();
 
diff --git a/src/DHTPeerAnnounceStorage.h b/src/DHTPeerAnnounceStorage.h
index 27e63eb4..1e085ca3 100644
--- a/src/DHTPeerAnnounceStorage.h
+++ b/src/DHTPeerAnnounceStorage.h
@@ -58,7 +58,7 @@ private:
 
   SharedHandle<DHTTaskFactory> _taskFactory;
 
-  const Logger* _logger;
+  Logger* _logger;
 public:
   DHTPeerAnnounceStorage();
 
diff --git a/src/DHTRoutingTable.h b/src/DHTRoutingTable.h
index 89640ae6..21721f98 100644
--- a/src/DHTRoutingTable.h
+++ b/src/DHTRoutingTable.h
@@ -61,7 +61,7 @@ private:
 
   SharedHandle<DHTTaskFactory> _taskFactory;
 
-  const Logger* _logger;
+  Logger* _logger;
 
   bool addNode(const SharedHandle<DHTNode>& node, bool good);
 public:
diff --git a/src/DHTSetup.h b/src/DHTSetup.h
index be001877..27a5c6a2 100644
--- a/src/DHTSetup.h
+++ b/src/DHTSetup.h
@@ -48,7 +48,7 @@ class DHTSetup {
 private:
   static size_t _initialized;
 
-  const Logger* _logger;
+  Logger* _logger;
 
 public:
   DHTSetup();
diff --git a/src/DHTTaskFactoryImpl.h b/src/DHTTaskFactoryImpl.h
index f8ab278e..d35e5323 100644
--- a/src/DHTTaskFactoryImpl.h
+++ b/src/DHTTaskFactoryImpl.h
@@ -59,7 +59,7 @@ private:
   
   WeakHandle<DHTTaskQueue> _taskQueue;
 
-  const Logger* _logger;
+  Logger* _logger;
 
   void setCommonProperty(const SharedHandle<DHTAbstractTask>& task);
 public:
diff --git a/src/DefaultBtContext.h b/src/DefaultBtContext.h
index 060e9f6d..b752b4d8 100644
--- a/src/DefaultBtContext.h
+++ b/src/DefaultBtContext.h
@@ -69,7 +69,7 @@ private:
 
   RequestGroup* _ownerRequestGroup;
 
-  const Logger* _logger;
+  Logger* _logger;
 
   void clear();
   void extractPieceHash(const unsigned char* hashData,
diff --git a/src/DefaultBtInteractive.h b/src/DefaultBtInteractive.h
index 625fbaa2..0e8a1425 100644
--- a/src/DefaultBtInteractive.h
+++ b/src/DefaultBtInteractive.h
@@ -98,7 +98,7 @@ private:
 
   WeakHandle<DHTNode> _localNode;
 
-  const Logger* logger;
+  Logger* logger;
   size_t allowedFastSetSize;
   Time haveCheckPoint;
   Time keepAliveCheckPoint;
diff --git a/src/DefaultBtMessageDispatcher.h b/src/DefaultBtMessageDispatcher.h
index c4fc9bad..0d63e48c 100644
--- a/src/DefaultBtMessageDispatcher.h
+++ b/src/DefaultBtMessageDispatcher.h
@@ -61,7 +61,7 @@ private:
   SharedHandle<Peer> peer;
   unsigned int maxUploadSpeedLimit;
   time_t requestTimeout;
-  const Logger* logger;
+  Logger* logger;
 public:
   DefaultBtMessageDispatcher();
 
diff --git a/src/DefaultBtMessageReceiver.h b/src/DefaultBtMessageReceiver.h
index 6bbcc4ee..8344eb10 100644
--- a/src/DefaultBtMessageReceiver.h
+++ b/src/DefaultBtMessageReceiver.h
@@ -55,7 +55,7 @@ private:
   WeakHandle<PeerConnection> peerConnection;
   WeakHandle<BtMessageDispatcher> dispatcher;
   WeakHandle<BtMessageFactory> messageFactory;
-  const Logger* logger;
+  Logger* logger;
 
   void sendHandshake();
 public:
diff --git a/src/DefaultBtProgressInfoFile.h b/src/DefaultBtProgressInfoFile.h
index f52ff67e..be7566e3 100644
--- a/src/DefaultBtProgressInfoFile.h
+++ b/src/DefaultBtProgressInfoFile.h
@@ -49,7 +49,7 @@ private:
   SharedHandle<DownloadContext> _dctx;
   SharedHandle<PieceStorage> _pieceStorage;
   const Option* _option;
-  const Logger* _logger;
+  Logger* _logger;
   std::string _filename;
 
   bool isTorrentDownload();
diff --git a/src/DefaultExtensionMessageFactory.h b/src/DefaultExtensionMessageFactory.h
index 4465bf46..6bbc45ef 100644
--- a/src/DefaultExtensionMessageFactory.h
+++ b/src/DefaultExtensionMessageFactory.h
@@ -49,7 +49,7 @@ private:
 
   SharedHandle<Peer> _peer;
 
-  const Logger* _logger;
+  Logger* _logger;
 
 public:
   DefaultExtensionMessageFactory();
diff --git a/src/DiskAdaptor.h b/src/DiskAdaptor.h
index 7b5c036b..df4acf1e 100644
--- a/src/DiskAdaptor.h
+++ b/src/DiskAdaptor.h
@@ -49,7 +49,7 @@ class DiskAdaptor:public BinaryStream {
 protected:
   std::string storeDir;
   std::deque<SharedHandle<FileEntry> > fileEntries;
-  const Logger* logger;
+  Logger* logger;
 public:
   DiskAdaptor();
   virtual ~DiskAdaptor();
diff --git a/src/DownloadEngine.h b/src/DownloadEngine.h
index 039a1246..6aa519b2 100644
--- a/src/DownloadEngine.h
+++ b/src/DownloadEngine.h
@@ -99,7 +99,7 @@ private:
   fd_set wfdset;
   int fdmax;
 
-  const Logger* logger;
+  Logger* logger;
   
   SharedHandle<StatCalc> _statCalc;
 
diff --git a/src/DownloadEngineFactory.h b/src/DownloadEngineFactory.h
index 662830a6..a381e4e9 100644
--- a/src/DownloadEngineFactory.h
+++ b/src/DownloadEngineFactory.h
@@ -48,7 +48,7 @@ class DownloadEngine;
 
 class DownloadEngineFactory {
 private:
-  const Logger* _logger;
+  Logger* _logger;
 public:
   DownloadEngineFactory();
 
diff --git a/src/DownloadHandler.h b/src/DownloadHandler.h
index c12a0a17..9c6681e3 100644
--- a/src/DownloadHandler.h
+++ b/src/DownloadHandler.h
@@ -51,7 +51,7 @@ class DownloadHandler
 protected:
   SharedHandle<RequestGroupCriteria> _criteria;
 
-  const Logger* _logger;
+  Logger* _logger;
 public:
   DownloadHandler();
 
diff --git a/src/FtpConnection.h b/src/FtpConnection.h
index bc0b597b..2f1f7709 100644
--- a/src/FtpConnection.h
+++ b/src/FtpConnection.h
@@ -54,7 +54,7 @@ private:
   SharedHandle<SocketCore> socket;
   SharedHandle<Request> req;
   const Option* option;
-  const Logger* logger;
+  Logger* logger;
 
   std::string strbuf;
 
diff --git a/src/HandshakeExtensionMessage.h b/src/HandshakeExtensionMessage.h
index 201891a0..ca33fc9e 100644
--- a/src/HandshakeExtensionMessage.h
+++ b/src/HandshakeExtensionMessage.h
@@ -59,7 +59,7 @@ private:
 
   SharedHandle<Peer> _peer;
 
-  const Logger* _logger;
+  Logger* _logger;
 
 public:
   HandshakeExtensionMessage();
diff --git a/src/HelpItemFactory.cc b/src/HelpItemFactory.cc
index bd5e9a11..5c9eccd2 100644
--- a/src/HelpItemFactory.cc
+++ b/src/HelpItemFactory.cc
@@ -40,6 +40,7 @@
 #include "a2io.h"
 #include "help_tags.h"
 #include "Option.h"
+#include "StringFormat.h"
 
 namespace aria2 {
 
@@ -459,9 +460,8 @@ TagContainerHandle HelpItemFactory::createHelpItems(const Option* op)
   }
   {
     HelpItemHandle item(new HelpItem("help", TEXT_HELP, TAG_BASIC));
-    char buf[64];
-    snprintf(buf, sizeof(buf), "%s,%s,%s,%s,%s,%s,all", TAG_BASIC, TAG_ADVANCED, TAG_HTTP, TAG_FTP, TAG_METALINK, TAG_BITTORRENT);
-    item->setAvailableValues(buf);
+    item->setAvailableValues
+      (StringFormat("%s,%s,%s,%s,%s,%s,all", TAG_BASIC, TAG_ADVANCED, TAG_HTTP, TAG_FTP, TAG_METALINK, TAG_BITTORRENT).toString());
     item->addTag(TAG_BASIC);
     tc->addItem(item);
   }
diff --git a/src/HttpConnection.h b/src/HttpConnection.h
index 21684fd2..3a6a21c3 100644
--- a/src/HttpConnection.h
+++ b/src/HttpConnection.h
@@ -72,7 +72,7 @@ private:
   int32_t cuid;
   SharedHandle<SocketCore> socket;
   const Option* option;
-  const Logger* logger;
+  Logger* logger;
 
   HttpRequestEntries outstandingHttpRequests;
 
diff --git a/src/HttpResponse.h b/src/HttpResponse.h
index 7ec54db9..04ea1153 100644
--- a/src/HttpResponse.h
+++ b/src/HttpResponse.h
@@ -51,7 +51,7 @@ private:
   int32_t cuid;
   SharedHandle<HttpRequest> httpRequest;
   SharedHandle<HttpHeader> httpHeader;
-  const Logger* logger;
+  Logger* logger;
 public:
   HttpResponse();
   
diff --git a/src/IteratableChecksumValidator.h b/src/IteratableChecksumValidator.h
index 5150e6a0..2a8997a8 100644
--- a/src/IteratableChecksumValidator.h
+++ b/src/IteratableChecksumValidator.h
@@ -55,7 +55,7 @@ private:
 
   SharedHandle<MessageDigestContext> _ctx;
 
-  const Logger* _logger;
+  Logger* _logger;
 
   unsigned char* _buffer;
 
diff --git a/src/IteratableChunkChecksumValidator.h b/src/IteratableChunkChecksumValidator.h
index 6d5e3e75..8517c378 100644
--- a/src/IteratableChunkChecksumValidator.h
+++ b/src/IteratableChunkChecksumValidator.h
@@ -52,7 +52,7 @@ private:
   SharedHandle<PieceStorage> _pieceStorage;
   BitfieldMan* _bitfield;
   size_t _currentIndex;
-  const Logger* _logger;
+  Logger* _logger;
   SharedHandle<MessageDigestContext> _ctx;
   unsigned char* _buffer;
 
diff --git a/src/Logger.h b/src/Logger.h
index 319ad84f..64a0e978 100644
--- a/src/Logger.h
+++ b/src/Logger.h
@@ -44,16 +44,16 @@ class Exception;
 class Logger {
 public:
   virtual ~Logger() {}
-  virtual void debug(const char* msg, ...) const = 0;
-  virtual void debug(const char* msg, Exception* ex, ...) const = 0;
-  virtual void info(const char* msg, ...) const = 0;
-  virtual void info(const char* msg, Exception* ex, ...) const = 0;
-  virtual void notice(const char* msg, ...) const = 0;
-  virtual void notice(const char* msg, Exception* ex, ...) const = 0;
-  virtual void warn(const char* msg, ...) const = 0;
-  virtual void warn(const char* msg, Exception* ex, ...) const = 0;
-  virtual void error(const char*  msg, ...) const = 0;
-  virtual void error(const char* msg, Exception* ex, ...) const = 0;
+  virtual void debug(const char* msg, ...) = 0;
+  virtual void debug(const char* msg, Exception* ex, ...) = 0;
+  virtual void info(const char* msg, ...) = 0;
+  virtual void info(const char* msg, Exception* ex, ...) = 0;
+  virtual void notice(const char* msg, ...) = 0;
+  virtual void notice(const char* msg, Exception* ex, ...) = 0;
+  virtual void warn(const char* msg, ...) = 0;
+  virtual void warn(const char* msg, Exception* ex, ...) = 0;
+  virtual void error(const char*  msg, ...) = 0;
+  virtual void error(const char* msg, Exception* ex, ...) = 0;
 
   enum LEVEL {
     DEBUG  = 1 << 0,
diff --git a/src/MSEHandshake.h b/src/MSEHandshake.h
index bb192a43..8dc43eff 100644
--- a/src/MSEHandshake.h
+++ b/src/MSEHandshake.h
@@ -78,7 +78,7 @@ private:
   int32_t _cuid;
   SharedHandle<SocketCore> _socket;
   const Option* _option;
-  const Logger* _logger;
+  Logger* _logger;
 
   unsigned char _rbuf[MAX_BUFFER_LENGTH];
   size_t _rbufLength;
diff --git a/src/Makefile.am b/src/Makefile.am
index 708f4457..e0126f56 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -182,7 +182,8 @@ SRCS =  Socket.h\
 	prefs.h\
 	usage_text.h\
 	ProtocolDetector.cc ProtocolDetector.h\
-	NullStatCalc.h
+	NullStatCalc.h\
+	StringFormat.cc StringFormat.h
 
 if ENABLE_MESSAGE_DIGEST
 SRCS += IteratableChunkChecksumValidator.cc IteratableChunkChecksumValidator.h\
diff --git a/src/Makefile.in b/src/Makefile.in
index 1748ebe0..3dd96acc 100644
--- a/src/Makefile.in
+++ b/src/Makefile.in
@@ -404,7 +404,8 @@ am__libaria2c_a_SOURCES_DIST = Socket.h SocketCore.cc SocketCore.h \
 	TrueRequestGroupCriteria.h a2algo.h a2functional.h a2io.h \
 	a2netcompat.h a2time.h array_fun.h help_tags.h prefs.h \
 	usage_text.h ProtocolDetector.cc ProtocolDetector.h \
-	NullStatCalc.h IteratableChunkChecksumValidator.cc \
+	NullStatCalc.h StringFormat.cc StringFormat.h \
+	IteratableChunkChecksumValidator.cc \
 	IteratableChunkChecksumValidator.h \
 	IteratableChecksumValidator.cc IteratableChecksumValidator.h \
 	CheckIntegrityCommand.cc CheckIntegrityCommand.h \
@@ -780,11 +781,11 @@ am__objects_14 = SocketCore.$(OBJEXT) Command.$(OBJEXT) \
 	HelpItem.$(OBJEXT) TaggedItem.$(OBJEXT) TagContainer.$(OBJEXT) \
 	HelpItemFactory.$(OBJEXT) SingleFileDownloadContext.$(OBJEXT) \
 	TimedHaltCommand.$(OBJEXT) ProtocolDetector.$(OBJEXT) \
-	$(am__objects_1) $(am__objects_2) $(am__objects_3) \
-	$(am__objects_4) $(am__objects_5) $(am__objects_6) \
-	$(am__objects_7) $(am__objects_8) $(am__objects_9) \
-	$(am__objects_10) $(am__objects_11) $(am__objects_12) \
-	$(am__objects_13)
+	StringFormat.$(OBJEXT) $(am__objects_1) $(am__objects_2) \
+	$(am__objects_3) $(am__objects_4) $(am__objects_5) \
+	$(am__objects_6) $(am__objects_7) $(am__objects_8) \
+	$(am__objects_9) $(am__objects_10) $(am__objects_11) \
+	$(am__objects_12) $(am__objects_13)
 am_libaria2c_a_OBJECTS = $(am__objects_14)
 libaria2c_a_OBJECTS = $(am_libaria2c_a_OBJECTS)
 am__installdirs = "$(DESTDIR)$(bindir)"
@@ -1119,11 +1120,11 @@ SRCS = Socket.h SocketCore.cc SocketCore.h BinaryStream.h Command.cc \
 	TrueRequestGroupCriteria.h a2algo.h a2functional.h a2io.h \
 	a2netcompat.h a2time.h array_fun.h help_tags.h prefs.h \
 	usage_text.h ProtocolDetector.cc ProtocolDetector.h \
-	NullStatCalc.h $(am__append_1) $(am__append_2) $(am__append_3) \
-	$(am__append_4) $(am__append_5) $(am__append_6) \
-	$(am__append_7) $(am__append_8) $(am__append_9) \
-	$(am__append_10) $(am__append_11) $(am__append_12) \
-	$(am__append_13)
+	NullStatCalc.h StringFormat.cc StringFormat.h $(am__append_1) \
+	$(am__append_2) $(am__append_3) $(am__append_4) \
+	$(am__append_5) $(am__append_6) $(am__append_7) \
+	$(am__append_8) $(am__append_9) $(am__append_10) \
+	$(am__append_11) $(am__append_12) $(am__append_13)
 noinst_LIBRARIES = libaria2c.a
 libaria2c_a_SOURCES = $(SRCS)
 aria2c_LDADD = libaria2c.a @LIBINTL@ @ALLOCA@ @LIBGNUTLS_LIBS@\
@@ -1459,6 +1460,7 @@ distclean-compile:
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/SpeedCalc.Po@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/StreamCheckIntegrityEntry.Po@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/StreamFileAllocationEntry.Po@am__quote@
+@AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/StringFormat.Po@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/TagContainer.Po@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/TaggedItem.Po@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/TimeA2.Po@am__quote@
diff --git a/src/Metalink2RequestGroup.h b/src/Metalink2RequestGroup.h
index 8c1d0075..fd591678 100644
--- a/src/Metalink2RequestGroup.h
+++ b/src/Metalink2RequestGroup.h
@@ -52,7 +52,7 @@ class Metalink2RequestGroup {
 private:
   const Option* _option;
 
-  const Logger* _logger;
+  Logger* _logger;
 
   std::deque<SharedHandle<RequestGroup> >
   createRequestGroup(std::deque<SharedHandle<MetalinkEntry> > entries);
diff --git a/src/MultiUrlRequestInfo.h b/src/MultiUrlRequestInfo.h
index a66dc9bb..ccf37346 100644
--- a/src/MultiUrlRequestInfo.h
+++ b/src/MultiUrlRequestInfo.h
@@ -57,7 +57,7 @@ private:
 
   std::ostream& _summaryOut;
 
-  const Logger* _logger;
+  Logger* _logger;
 
   void printMessageForContinue();
 
diff --git a/src/PeerConnection.h b/src/PeerConnection.h
index 57e97c9f..cccf13c5 100644
--- a/src/PeerConnection.h
+++ b/src/PeerConnection.h
@@ -56,7 +56,7 @@ private:
   int32_t cuid;
   SharedHandle<SocketCore> socket;
   const Option* option;
-  const Logger* logger;
+  Logger* logger;
 
   unsigned char resbuf[MAX_PAYLOAD_LEN];
   size_t resbufLength;
diff --git a/src/Request.cc b/src/Request.cc
index 545dc600..e06f1981 100644
--- a/src/Request.cc
+++ b/src/Request.cc
@@ -38,6 +38,7 @@
 #include "CookieBoxFactory.h"
 #include "CookieBox.h"
 #include "RecoverableException.h"
+#include "StringFormat.h"
 #include <utility>
 
 namespace aria2 {
@@ -180,10 +181,7 @@ std::string Request::urlencode(const std::string& src) const
 	  result.replace(index, 1, "%25");
 	}
       } else {
-	char temp[4];
-	sprintf(temp, "%%%02x", c);
-	temp[3] = '\0';
-	result.replace(index, 1, temp);
+	result.replace(index, 1, StringFormat("%%%02x", c).toString());
       }
     }
   }
diff --git a/src/RequestGroup.h b/src/RequestGroup.h
index b6958ebd..657eb2c9 100644
--- a/src/RequestGroup.h
+++ b/src/RequestGroup.h
@@ -112,7 +112,7 @@ private:
 
   const Option* _option;
 
-  const Logger* _logger;
+  Logger* _logger;
 
   void validateFilename(const std::string& expectedFilename,
 			const std::string& actualFilename) const;
diff --git a/src/RequestGroupMan.h b/src/RequestGroupMan.h
index b70d46fb..65f56705 100644
--- a/src/RequestGroupMan.h
+++ b/src/RequestGroupMan.h
@@ -55,7 +55,7 @@ private:
   std::deque<SharedHandle<RequestGroup> > _requestGroups;
   std::deque<SharedHandle<RequestGroup> > _reservedGroups;
   std::deque<SharedHandle<DownloadResult> > _downloadResults;
-  const Logger* _logger;
+  Logger* _logger;
   unsigned int _maxSimultaneousDownloads;
   int32_t _gidCounter;
 
diff --git a/src/SegmentMan.h b/src/SegmentMan.h
index 8807ee48..2519cf55 100644
--- a/src/SegmentMan.h
+++ b/src/SegmentMan.h
@@ -69,7 +69,7 @@ class SegmentMan {
 private:
   const Option* _option;
 
-  const Logger* logger;
+  Logger* logger;
 
   SharedHandle<DownloadContext> _downloadContext;
 
diff --git a/src/SimpleLogger.cc b/src/SimpleLogger.cc
index e6425e63..2dc5ab1d 100644
--- a/src/SimpleLogger.cc
+++ b/src/SimpleLogger.cc
@@ -38,8 +38,11 @@
 #include "message.h"
 #include "a2io.h"
 #include "a2time.h"
+#include "StringFormat.h"
 #include <cerrno>
 #include <cstring>
+#include <iostream>
+#include <cstdlib>
 
 namespace aria2 {
 
@@ -63,22 +66,22 @@ va_start(ap, EX);\
 writeFile(Logger::LEVEL, MSG, ap, EX);\
 va_end(ap);
 
-SimpleLogger::SimpleLogger(FILE* logfile):file(logfile), stdoutField(0) {}
+SimpleLogger::SimpleLogger():stdoutField(0) {}
 
 SimpleLogger::~SimpleLogger() {
   closeFile();
 }
 
 void SimpleLogger::openFile(const std::string& filename) {
-  file = fopen(filename.c_str(), "ab");
-  if(file == NULL) {
+  file.open(filename.c_str(), std::ios::app|std::ios::binary);
+  if(!file) {
     throw new DlAbortEx(EX_FILE_OPEN, filename.c_str(), strerror(errno));
   }
 }
 
 void SimpleLogger::closeFile() {
-  if(file != NULL) {
-    fclose(file);
+  if(file.is_open()) {
+    file.close();
   }
 }
 
@@ -90,13 +93,15 @@ void SimpleLogger::setStdout(Logger::LEVEL level, bool enabled) {
   }
 }
 
-void SimpleLogger::writeHeader(FILE* file,
-			       const std::string& date, const std::string& level) const
+void SimpleLogger::writeHeader(std::ostream& o, const std::string& date,
+			       const std::string& level)
 {
-  fprintf(file, "%s %s - ", date.c_str(), level.c_str());
+  o << StringFormat("%s %s - ", date.c_str(), level.c_str());
 }
 
-void SimpleLogger::writeLog(FILE* file, Logger::LEVEL level, const char* msg, va_list ap, Exception* e, bool printHeader) const
+void SimpleLogger::writeLog(std::ostream& o, Logger::LEVEL level,
+			    const char* msg, va_list ap, Exception* e,
+			    bool printHeader)
 {
   va_list apCopy;
   va_copy(apCopy, ap);
@@ -126,65 +131,74 @@ void SimpleLogger::writeLog(FILE* file, Logger::LEVEL level, const char* msg, va
 
   // TODO a quick hack not to print header in console
   if(printHeader) {
-    writeHeader(file, datestr, levelStr);
+    writeHeader(o, datestr, levelStr);
+  }
+  {
+    char* res;
+    if(vasprintf(&res, std::string(Util::replace(msg, "\r", "")+"\n").c_str(), apCopy) == -1) {
+      o << "SimpleLogger error, cannot allocate memory.\n";
+    } else {
+      o << res;
+      free(res);
+    }
   }
-  vfprintf(file, std::string(Util::replace(msg, "\r", "")+"\n").c_str(), apCopy);
   for(Exception* nestedEx = e; nestedEx; nestedEx = nestedEx->getCause()) {
     // TODO a quick hack not to print header in console
     if(printHeader) {
-      writeHeader(file, datestr, levelStr);
+      writeHeader(o, datestr, levelStr);
     }
-    fprintf(file, "exception: %s\n", Util::replace(nestedEx->getMsg(), "\r", "").c_str());
+    o << StringFormat("exception: %s\n", Util::replace(nestedEx->getMsg(), "\r", "").c_str());
   }
-  fflush(file);
+  o << std::flush;
   va_end(apCopy);
 }
 
-void SimpleLogger::writeFile(Logger::LEVEL level, const char* msg, va_list ap, Exception* e) const {
+void SimpleLogger::writeFile(Logger::LEVEL level, const char* msg, va_list ap, Exception* e)
+{
   writeLog(file, level, msg, ap, e);
   if(stdoutField&level) {
-    fprintf(stdout, "\n");
-    writeLog(stdout, level, msg, ap, e);
+    std::cout << "\n";
+    writeLog(std::cout, level, msg, ap, e);
   }
 }
 
-void SimpleLogger::debug(const char* msg, ...) const {
+void SimpleLogger::debug(const char* msg, ...) {
   WRITE_LOG(DEBUG, msg);
 }
 
-void SimpleLogger::debug(const char* msg, Exception* e, ...) const {
+void SimpleLogger::debug(const char* msg, Exception* e, ...) {
   WRITE_LOG_EX(DEBUG, msg, e);
 }
 
-void SimpleLogger::info(const char* msg, ...) const {
+void SimpleLogger::info(const char* msg, ...) {
   WRITE_LOG(INFO, msg);
 }
 
-void SimpleLogger::info(const char* msg, Exception* e, ...) const {
+void SimpleLogger::info(const char* msg, Exception* e, ...) {
   WRITE_LOG_EX(INFO, msg, e);
 }
 
-void SimpleLogger::notice(const char* msg, ...) const {
+void SimpleLogger::notice(const char* msg, ...) {
   WRITE_LOG(NOTICE, msg);
 }
 
-void SimpleLogger::notice(const char* msg, Exception* e, ...) const {
+void SimpleLogger::notice(const char* msg, Exception* e, ...) {
   WRITE_LOG_EX(INFO, msg, e);
 }
 
-void SimpleLogger::warn(const char* msg, ...) const {
+void SimpleLogger::warn(const char* msg, ...) {
   WRITE_LOG(WARN, msg);
 }
 
-void SimpleLogger::warn(const char* msg, Exception* e, ...) const {
+void SimpleLogger::warn(const char* msg, Exception* e, ...) {
   WRITE_LOG_EX(WARN, msg, e);
 }
 
-void SimpleLogger::error(const char* msg, ...) const {
+void SimpleLogger::error(const char* msg, ...) {
   WRITE_LOG(ERROR, msg);
 }
 
-void SimpleLogger::error(const char* msg, Exception* e, ...) const {
+void SimpleLogger::error(const char* msg, Exception* e, ...) {
   WRITE_LOG_EX(ERROR, msg, e);
 }
 
diff --git a/src/SimpleLogger.h b/src/SimpleLogger.h
index 616ee5e1..8d32c4e8 100644
--- a/src/SimpleLogger.h
+++ b/src/SimpleLogger.h
@@ -36,38 +36,39 @@
 #define _D_SIMPLE_LOGGER_H_
 
 #include "Logger.h"
-#include <cstdio>
 #include <cstdarg>
 #include <string>
+#include <fstream>
 
 namespace aria2 {
 
 class SimpleLogger:public Logger {
 private:
-  void writeFile(Logger::LEVEL level, const char* msg, va_list ap, Exception* e = 0) const;
-  void writeHeader(FILE* file,
-		   const std::string& date, const std::string& level) const;
-  void writeLog(FILE* file, Logger::LEVEL level,
+  void writeFile(Logger::LEVEL level, const char* msg, va_list ap, Exception* e = 0);
+  void writeHeader(std::ostream& out,
+		   const std::string& date, const std::string& level);
+  void writeLog(std::ostream& out, Logger::LEVEL level,
 		const char* msg, va_list ap,
-		Exception* e = 0, bool printHeader = true) const;
-  FILE* file;
+		Exception* e = 0, bool printHeader = true);
+
+  std::ofstream file;
   int stdoutField;
 public:
-  SimpleLogger(FILE* logfile = 0);
+  SimpleLogger();
   ~SimpleLogger();
 
   void openFile(const std::string& filename);
   void closeFile();
-  virtual void debug(const char* msg, ...) const;
-  virtual void debug(const char* msg, Exception* ex, ...) const;
-  virtual void info(const char* msg, ...) const;
-  virtual void info(const char* msg, Exception* ex, ...) const;
-  virtual void notice(const char* msg, ...) const;
-  virtual void notice(const char* msg, Exception* ex, ...) const;
-  virtual void warn(const char* msg, ...) const;
-  virtual void warn(const char* msg, Exception* ex, ...) const;
-  virtual void error(const char* msg, ...) const;
-  virtual void error(const char* msg, Exception* ex, ...) const;
+  virtual void debug(const char* msg, ...);
+  virtual void debug(const char* msg, Exception* ex, ...);
+  virtual void info(const char* msg, ...);
+  virtual void info(const char* msg, Exception* ex, ...);
+  virtual void notice(const char* msg, ...);
+  virtual void notice(const char* msg, Exception* ex, ...);
+  virtual void warn(const char* msg, ...);
+  virtual void warn(const char* msg, Exception* ex, ...);
+  virtual void error(const char* msg, ...);
+  virtual void error(const char* msg, Exception* ex, ...);
 
   void setStdout(Logger::LEVEL level, bool enabled);
 };
diff --git a/src/StringFormat.cc b/src/StringFormat.cc
new file mode 100644
index 00000000..2dadc0ac
--- /dev/null
+++ b/src/StringFormat.cc
@@ -0,0 +1,67 @@
+/* <!-- copyright */
+/*
+ * aria2 - The high speed download utility
+ *
+ * Copyright (C) 2006 Tatsuhiro Tsujikawa
+ *
+ * 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 2 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, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+ *
+ * In addition, as a special exception, the copyright holders give
+ * permission to link the code of portions of this program with the
+ * OpenSSL library under certain conditions as described in each
+ * individual source file, and distribute linked combinations
+ * including the two.
+ * You must obey the GNU General Public License in all respects
+ * for all of the code used other than OpenSSL.  If you modify
+ * file(s) with this exception, you may extend this exception to your
+ * version of the file(s), but you are not obligated to do so.  If you
+ * do not wish to do so, delete this exception statement from your
+ * version.  If you delete this exception statement from all source
+ * files in the program, then also delete it here.
+ */
+/* copyright --> */
+#include "StringFormat.h"
+#include <ostream>
+#include <cstring>
+#include <cstdio>
+#include <cstdarg>
+#include <cstdlib>
+
+namespace aria2 {
+
+StringFormat::StringFormat(const char* fmt, ...)
+{
+  va_list ap;
+  va_start(ap, fmt);
+  char* strp;
+  if(vasprintf(&strp, fmt, ap) != -1) {
+    _msg.assign(&strp[0], &strp[strlen(strp)]);
+    free(strp);
+  }
+  va_end(ap);
+}
+
+const std::string& StringFormat::toString() const
+{
+  return _msg;
+}
+
+std::ostream& operator<<(std::ostream& o, const StringFormat& fmt)
+{
+  o << fmt.toString();
+  return o;
+}
+
+} // namespace aria2
diff --git a/src/StringFormat.h b/src/StringFormat.h
new file mode 100644
index 00000000..f119863b
--- /dev/null
+++ b/src/StringFormat.h
@@ -0,0 +1,57 @@
+/* <!-- copyright */
+/*
+ * aria2 - The high speed download utility
+ *
+ * Copyright (C) 2006 Tatsuhiro Tsujikawa
+ *
+ * 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 2 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, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+ *
+ * In addition, as a special exception, the copyright holders give
+ * permission to link the code of portions of this program with the
+ * OpenSSL library under certain conditions as described in each
+ * individual source file, and distribute linked combinations
+ * including the two.
+ * You must obey the GNU General Public License in all respects
+ * for all of the code used other than OpenSSL.  If you modify
+ * file(s) with this exception, you may extend this exception to your
+ * version of the file(s), but you are not obligated to do so.  If you
+ * do not wish to do so, delete this exception statement from your
+ * version.  If you delete this exception statement from all source
+ * files in the program, then also delete it here.
+ */
+/* copyright --> */
+#ifndef _D_STRING_FORMAT_H_
+#define _D_STRING_FORMAT_H_
+
+#include <string>
+#include <iosfwd>
+#include <cstdarg>
+
+namespace aria2 {
+
+class StringFormat {
+private:
+  std::string _msg;
+public:
+  StringFormat(const char* fmt, ...);
+
+  const std::string& toString() const;
+};
+
+std::ostream& operator<<(std::ostream& o, const StringFormat& fmt);
+
+} // namespace aria2
+
+#endif // _D_STRING_FORMAT_H_
diff --git a/src/Util.cc b/src/Util.cc
index c137704a..25829b9e 100644
--- a/src/Util.cc
+++ b/src/Util.cc
@@ -42,6 +42,7 @@
 #include "DefaultDiskWriter.h"
 #include "FatalException.h"
 #include "FileEntry.h"
+#include "StringFormat.h"
 #include <signal.h>
 #include <cerrno>
 #include <cassert>
@@ -205,10 +206,7 @@ std::string Util::urlencode(const unsigned char* target, size_t len) {
   std::string dest;
   for(size_t i = 0; i < len; i++) {
     if(shouldUrlencode(target[i])) {
-      char temp[4];
-      sprintf(temp, "%%%02x", target[i]);
-      temp[sizeof(temp)-1] = '\0';
-      dest.append(temp);
+      dest.append(StringFormat("%%%02x", target[i]).toString());
     } else {
       dest += target[i];
     }
@@ -224,10 +222,7 @@ std::string Util::torrentUrlencode(const unsigned char* target, size_t len) {
        ('a' <= target[i] && target[i] <= 'z')) {
       dest += target[i];
     } else {
-      char temp[4];
-      sprintf(temp, "%%%02x", target[i]);
-      temp[sizeof(temp)-1] = '\0';
-      dest.append(temp);
+      dest.append(StringFormat("%%%02x", target[i]).toString());
     }
   }
   return dest;
diff --git a/src/option_processing.cc b/src/option_processing.cc
index 4a5b78a8..0f344bd6 100644
--- a/src/option_processing.cc
+++ b/src/option_processing.cc
@@ -44,6 +44,7 @@
 #include "a2io.h"
 #include "help_tags.h"
 #include "File.h"
+#include "StringFormat.h"
 #include <cstdlib>
 #include <fstream>
 #include <sstream>
@@ -523,8 +524,8 @@ Option* option_processing(int argc, char* const argv[])
 	  exit(EXIT_FAILURE);
 	}
       } else if(ucfname.size()) {
-	printf("Configuration file %s is not found.", cfname.c_str());
-	std::cout << "\n";
+	std::cout << StringFormat("Configuration file %s is not found.", cfname.c_str())
+		  << "\n";
       }
     }
     try {
diff --git a/src/version_usage.cc b/src/version_usage.cc
index 7add5a5c..65c645b3 100644
--- a/src/version_usage.cc
+++ b/src/version_usage.cc
@@ -44,6 +44,7 @@
 #include "HelpItemFactory.h"
 #include "help_tags.h"
 #include "prefs.h"
+#include "StringFormat.h"
 #include <iostream>
 #include <iterator>
 #include <algorithm>
@@ -89,34 +90,34 @@ void showVersion() {
 #ifdef ENABLE_MESSAGE_DIGEST
 	    << "message digest algorithms: " << MessageDigestContext::getSupportedAlgoString() << "\n"
 #endif // ENABLE_MESSAGE_DIGEST
-	    << "\n";
-  printf(_("Report bugs to %s"), "<tujikawa at users dot sourceforge dot net>");
-  std::cout << std::endl;
+	    << "\n"
+	    << StringFormat(_("Report bugs to %s"), "<tujikawa at users dot sourceforge dot net>")
+	    << std::endl;
 }
 
 void showUsage(const std::string& category, const Option* option) {
-  printf(_("Usage: %s [options] URL ...\n"), PACKAGE_NAME);
+  std::cout << StringFormat(_("Usage: %s [options] URL ...\n"), PACKAGE_NAME)
 #ifdef ENABLE_BITTORRENT
-  printf(_("       %s [options] -T TORRENT_FILE URL ...\n"), PACKAGE_NAME);
+	    << StringFormat(_("       %s [options] -T TORRENT_FILE URL ...\n"), PACKAGE_NAME)
 #endif // ENABLE_BITTORRENT
 #ifdef ENABLE_METALINK
-  printf(_("       %s [options] -M METALINK_FILE\n"), PACKAGE_NAME);
+	    << StringFormat(_("       %s [options] -M METALINK_FILE\n"), PACKAGE_NAME)
 #endif // ENABLE_METALINK
-  std::cout << "\n";
+	    << "\n";
 
   SharedHandle<TagContainer> tc = HelpItemFactory::createHelpItems(option);
   std::deque<SharedHandle<TaggedItem> > items =
     category == V_ALL ? tc->getAllItems() : tc->search(category);
   if(items.size() > 0) {
     if(category == V_ALL) {
-      printf(_("Printing all options."));
+      std::cout << _("Printing all options.");
     } else {
-      printf(_("Printing options tagged with '%s'."), category.c_str());
+      std::cout << StringFormat(_("Printing options tagged with '%s'."), category.c_str());
       std::cout << "\n";
       SharedHandle<HelpItem> helpItem
 	(dynamic_pointer_cast<HelpItem>(tc->nameMatch("help")));
-      printf(_("See -h option to know other command-line options(%s)."),
-	     helpItem->getAvailableValues().c_str());
+      std::cout << StringFormat(_("See -h option to know other command-line options(%s)."),
+				helpItem->getAvailableValues().c_str());
     }
     std::cout << "\n"
 	      << _("Options:") << "\n";
@@ -126,13 +127,13 @@ void showUsage(const std::string& category, const Option* option) {
   } else {
     std::deque<SharedHandle<TaggedItem> > items = tc->nameMatchForward(category);
     if(items.size() > 0) {
-      printf(_("Printing options whose name starts with '%s'."), category.c_str());
-      std::cout << "\n"
+      std::cout << StringFormat(_("Printing options whose name starts with '%s'."), category.c_str())
+		<< "\n"
 		<< _("Options:") << "\n";
       std::copy(items.begin(), items.end(), std::ostream_iterator<SharedHandle<TaggedItem> >(std::cout, "\n"));
     } else {
-      printf(_("No help category or option name matching with '%s'."), category.c_str());
-      std::cout << "\n" << tc->nameMatch("help") << "\n";
+      std::cout << StringFormat(_("No help category or option name matching with '%s'."), category.c_str())
+		<< "\n" << tc->nameMatch("help") << "\n";
     }
   }
   if(category == TAG_BASIC) {