Bloom Filter, first version

libwhisper/BloomFilter.cpp

@@ -27,11 +27,11 @@ using namespace dev::shh;
 
 bool BloomFilter::matches(AbridgedTopic const& _t) const
 {
-	static unsigned const c_PerfectMatch = ~unsigned(0);
+	static unsigned const c_match = ~unsigned(0);
 	unsigned topic = AbridgedTopic::Arith(_t).convert_to<unsigned>();
 	unsigned matchingBits = m_filter & topic;
 	matchingBits |= ~topic;
-	return (c_PerfectMatch == matchingBits);
+	return (c_match == matchingBits);
 }
 
 void SharedBloomFilter::add(AbridgedTopic const& _t)
@@ -46,7 +46,8 @@ void SharedBloomFilter::add(AbridgedTopic const& _t)
 				m_refCounter[i]++;
 			//else: overflow
 
-	// in order to encounter overflow, you have to set 65536 filters simultaneously.
+	// in order to encounter overflow, you have to set at least 65536 filters simultaneously.
+	// even then, the problem will only arise after at least 65536 filters will be be removed.
 	// we assume, it will never happen.
 }
 

libwhisper/BloomFilter.h

@@ -36,7 +36,12 @@ public:
 	BloomFilter(unsigned _i): m_filter(_i) {}
 	BloomFilter(AbridgedTopic const& _t): m_filter(AbridgedTopic::Arith(_t).convert_to<unsigned>()) {}
 
+	unsigned getUnsigned() const { return m_filter; }
+	AbridgedTopic getAbridgedTopic() const { return AbridgedTopic(m_filter); }
+
 	bool matches(AbridgedTopic const& _t) const;
+	virtual void add(Topic const& _t) { add(abridge(_t)); }
+	virtual void add(Topics const& _topics) { for (Topic t : _topics) add(abridge(t)); }
 	virtual void add(AbridgedTopic const& _t) { m_filter |= AbridgedTopic::Arith(_t).convert_to<unsigned>(); }
 	virtual void remove(AbridgedTopic const&) {} // not implemented in this class, use derived class instead.
 

libwhisper/Common.cpp

@@ -20,9 +20,9 @@
  */
 
 #include "Common.h"
-
 #include <libdevcore/SHA3.h>
 #include "Message.h"
+
 using namespace std;
 using namespace dev;
 using namespace dev::p2p;
@@ -84,6 +84,26 @@ bool TopicFilter::matches(Envelope const& _e) const
 	return false;
 }
 
+TopicFilter::TopicFilter(RLP const& _r)
+{
+	for (RLP i: _r)
+	{
+		m_topicMasks.push_back(TopicMask());
+		for (RLP j: i)
+			m_topicMasks.back().push_back(j.toPair<FixedHash<4>, FixedHash<4>>());
+	}
+}
+
+AbridgedTopic TopicFilter::exportBloomFilter() const
+{
+	AbridgedTopic ret;
+	for (TopicMask const& t: m_topicMasks)
+		for (auto i: t)
+			ret |= i.first;		
+		
+	return ret;
+}
+
 TopicMask BuildTopicMask::toTopicMask() const
 {
 	TopicMask ret;

libwhisper/Common.h

@@ -48,7 +48,6 @@ using h256Set = dev::h256Set;
 class WhisperHost;
 class WhisperPeer;
 class Whisper;
-
 class Envelope;
 
 enum WhisperPacket
@@ -91,7 +90,7 @@ protected:
 	h256s m_parts;
 };
 
-using TopicMask = std::vector<std::pair<AbridgedTopic, AbridgedTopic>>;
+using TopicMask = std::vector<std::pair<AbridgedTopic, AbridgedTopic>>; // where pair::first is the actual abridged topic hash, pair::second is a constant (probably redundunt)
 using TopicMasks = std::vector<TopicMask>;
 
 class TopicFilter
@@ -101,20 +100,12 @@ public:
 	TopicFilter(Topics const& _m) { m_topicMasks.push_back(TopicMask()); for (auto const& h: _m) m_topicMasks.back().push_back(std::make_pair(abridge(h), h ? ~AbridgedTopic() : AbridgedTopic())); }
 	TopicFilter(TopicMask const& _m): m_topicMasks(1, _m) {}
 	TopicFilter(TopicMasks const& _m): m_topicMasks(_m) {}
-	TopicFilter(RLP const& _r)//: m_topicMasks(_r.toVector<std::vector<>>())
-	{
-		for (RLP i: _r)
-		{
-			m_topicMasks.push_back(TopicMask());
-			for (RLP j: i)
-				m_topicMasks.back().push_back(j.toPair<FixedHash<4>, FixedHash<4>>());
-		}
-	}
+	TopicFilter(RLP const& _r);
 
 	void streamRLP(RLPStream& _s) const { _s << m_topicMasks; }
 	h256 sha3() const;
-
 	bool matches(Envelope const& _m) const;
+	AbridgedTopic exportBloomFilter() const;
 
 private:
 	TopicMasks m_topicMasks;

libwhisper/WhisperHost.cpp

@@ -113,6 +113,7 @@ unsigned WhisperHost::installWatch(shh::Topics const& _t)
 	if (!m_filters.count(h))
 		m_filters.insert(make_pair(h, f));
 
+	m_bloom.add(f.filter.exportBloomFilter());
 	return installWatchOnId(h);
 }
 
@@ -151,9 +152,12 @@ void WhisperHost::uninstallWatch(unsigned _i)
 
 	auto fit = m_filters.find(id);
 	if (fit != m_filters.end())
+	{
+		m_bloom.remove(fit->second.filter.exportBloomFilter());
 		if (!--fit->second.refCount)
 			m_filters.erase(fit);
 	}
+}
 
 void WhisperHost::doWork()
 {

libwhisper/WhisperHost.h

@@ -34,6 +34,7 @@
 #include "Common.h"
 #include "WhisperPeer.h"
 #include "Interface.h"
+#include "BloomFilter.h"
 
 namespace dev
 {
@@ -60,7 +61,7 @@ public:
 	virtual void uninstallWatch(unsigned _watchId) override;
 	virtual h256s peekWatch(unsigned _watchId) const override { dev::Guard l(m_filterLock); try { return m_watches.at(_watchId).changes; } catch (...) { return h256s(); } }
 	virtual h256s checkWatch(unsigned _watchId) override { cleanup(); dev::Guard l(m_filterLock); h256s ret; try { ret = m_watches.at(_watchId).changes; m_watches.at(_watchId).changes.clear(); } catch (...) {} return ret; }
-	virtual h256s watchMessages(unsigned _watchId) override;
+	virtual h256s watchMessages(unsigned _watchId) override; /// returns IDs of messages, which match specific watch criteria
 
 	virtual Envelope envelope(h256 _m) const override { try { dev::ReadGuard l(x_messages); return m_messages.at(_m); } catch (...) { return Envelope(); } }
 
@@ -86,6 +87,7 @@ private:
 	mutable dev::Mutex m_filterLock;
 	std::map<h256, InstalledFilter> m_filters;
 	std::map<unsigned, ClientWatch> m_watches;
+	SharedBloomFilter m_bloom;
 };
 
 }

test/libwhisper/bloomFilter.cpp

@@ -44,6 +44,14 @@ BOOST_AUTO_TEST_CASE(match)
 	unsigned b00110110 = 0x36;
 	unsigned b00110111 = 0x37;
 
+	AbridgedTopic x(b00111000);
+	SharedBloomFilter f1(b00111000);
+	SharedBloomFilter f2(x);
+	BOOST_REQUIRE_EQUAL(x, f1.getAbridgedTopic());
+	BOOST_REQUIRE_EQUAL(x, f2.getAbridgedTopic());
+	BOOST_REQUIRE_EQUAL(b00111000, f1.getUnsigned());
+	BOOST_REQUIRE_EQUAL(b00111000, f2.getUnsigned());
+
 	BOOST_REQUIRE(!f.matches(AbridgedTopic(b00000001)));
 	f.add(AbridgedTopic(b00000001));
 	BOOST_REQUIRE(!f.matches(AbridgedTopic(b00010000)));