Initial import of svn+ssh:://svn.icir.org/bro/trunk/bro as of r7088

src/IOSource.h

@@ -0,0 +1,105 @@
+// $Id: IOSource.h 6888 2009-08-20 18:23:11Z vern $
+//
+// Interface for classes providing/consuming data during Bro's main loop.
+
+#ifndef iosource_h
+#define iosource_h
+
+#include <list>
+#include "Timer.h"
+
+using namespace std;
+
+class IOSource {
+public:
+	IOSource()	{ idle = closed = false; }
+	virtual ~IOSource()	{}
+
+	// Returns true if source has nothing ready to process.
+	bool IsIdle() const	{ return idle; }
+
+	// Returns true if more data is to be expected in the future.
+	// Otherwise, source may be removed.
+	bool IsOpen() const	{ return ! closed; }
+
+	// Returns select'able fds (leaves args untouched if we don't have
+	// selectable fds).
+	virtual void GetFds(int* read, int* write, int* except) = 0;
+
+	// The following two methods are only called when either IsIdle()
+	// returns false or select() on one of the fds indicates that there's
+	// data to process.
+
+	// Returns timestamp (in global network time) associated with next
+	// data item.  If the source wants the data item to be processed
+	// with a local network time, it sets the argument accordingly.
+	virtual double NextTimestamp(double* network_time) = 0;
+
+	// Processes and consumes next data item.
+	virtual void Process() = 0;
+
+	// Returns tag of timer manager associated with last processed
+	// data item, nil for global timer manager.
+	virtual TimerMgr::Tag* GetCurrentTag()	{ return 0; }
+
+	// Returns a descriptual tag for debugging.
+	virtual const char* Tag() = 0;
+
+protected:
+	// Derived classed are to set this to true if they have gone dry
+	// temporarily.
+	bool idle;
+
+	// Derived classed are to set this to true if they have gone dry
+	// permanently.
+	bool closed;
+};
+
+class IOSourceRegistry {
+public:
+	IOSourceRegistry()	{ call_count = 0; dont_counts = 0; }
+	~IOSourceRegistry();
+
+	// If dont_count is true, this source does not contribute to the
+	// number of IOSources returned by Size().  The effect is that
+	// if all sources but the non-counting ones have gone dry,
+	// processing will shut down.
+	void Register(IOSource* src, bool dont_count = false);
+
+	// This may block for some time.
+	IOSource* FindSoonest(double* ts);
+
+	int Size() const	{ return sources.size() - dont_counts; }
+
+	// Terminate IOSource processing immediately by removing all
+	// sources (and therefore returning a Size() of zero).
+	void Terminate()	{ RemoveAll(); }
+
+protected:
+	// When looking for a source with something to process,
+	// every SELECT_FREQUENCY calls we will go ahead and
+	// block on a select().
+	static const int SELECT_FREQUENCY = 25;
+
+	// Microseconds to wait in an empty select if no source is ready.
+	static const int SELECT_TIMEOUT = 50;
+
+	void RemoveAll();
+
+	unsigned int call_count;
+	int dont_counts;
+
+	struct Source {
+		IOSource* src;
+		int fd_read;
+		int fd_write;
+		int fd_except;
+	};
+
+	typedef list<Source*> SourceList;
+	SourceList sources;
+};
+
+extern IOSourceRegistry io_sources;
+
+#endif