diff --git a/headers/os/package/PackageInfoSet.h b/headers/os/package/PackageInfoSet.h
index f2545ff73e..35fbbdc2be 100644
--- a/headers/os/package/PackageInfoSet.h
+++ b/headers/os/package/PackageInfoSet.h
@@ -21,16 +21,20 @@ public:
 
 public:
 								BPackageInfoSet();
+								BPackageInfoSet(const BPackageInfoSet& other);
 	virtual						~BPackageInfoSet();
 
-			status_t			Init();
-
 			status_t			AddInfo(const BPackageInfo& info);
 			void				MakeEmpty();
 
 			uint32				CountInfos() const;
 			Iterator			GetIterator() const;
 
+			BPackageInfoSet&	operator=(const BPackageInfoSet& other);
+
+private:
+			bool				_CopyOnWrite();
+
 private:
 			struct PackageInfo;
 			struct PackageInfoHashDefinition;
@@ -46,7 +50,7 @@ private:
 class BPackageInfoSet::Iterator {
 public:
 								Iterator();
-								Iterator(const BPackageInfoSet* set);
+								Iterator(const PackageMap* map);
 
 			bool				HasNext() const;
 			const BPackageInfo*	Next();
@@ -55,7 +59,7 @@ private:
 			friend class BRepositoryCache;
 
 private:
-			const BPackageInfoSet* fSet;
+			const PackageMap*	fMap;
 			PackageInfo*		fNextInfo;
 };
 
diff --git a/src/kits/package/PackageInfoSet.cpp b/src/kits/package/PackageInfoSet.cpp
index 315cedcd92..997e1dced5 100644
--- a/src/kits/package/PackageInfoSet.cpp
+++ b/src/kits/package/PackageInfoSet.cpp
@@ -12,6 +12,10 @@
 
 #include <new>
 
+#include <Referenceable.h>
+
+#include <AutoDeleter.h>
+
 #include <util/OpenHashTable.h>
 
 #include <package/PackageInfo.h>
@@ -33,6 +37,16 @@ struct BPackageInfoSet::PackageInfo : public BPackageInfo {
 		listNext(NULL)
 	{
 	}
+
+	void DeleteList()
+	{
+		PackageInfo* info = this;
+		while (info != NULL) {
+			PackageInfo* next = info->listNext;
+			delete info;
+			info = next;
+		}
+	}
 };
 
 
@@ -68,8 +82,8 @@ struct BPackageInfoSet::PackageInfoHashDefinition {
 // #pragma mark - PackageMap
 
 
-struct BPackageInfoSet::PackageMap
-	: public BOpenHashTable<PackageInfoHashDefinition> {
+struct BPackageInfoSet::PackageMap : public BReferenceable,
+	public BOpenHashTable<PackageInfoHashDefinition> {
 
 	PackageMap()
 		:
@@ -79,12 +93,34 @@ struct BPackageInfoSet::PackageMap
 
 	~PackageMap()
 	{
-		PackageInfo* info = Clear(true);
-		while (info != NULL) {
-			PackageInfo* next = info->hashNext;
-			delete info;
-			info = next;
+		DeleteAllPackageInfos();
+	}
+
+	static PackageMap* Create()
+	{
+		PackageMap* map = new(std::nothrow) PackageMap;
+		if (map == NULL || map->Init() != B_OK) {
+			delete map;
+			return NULL;
 		}
+
+		return map;
+	}
+
+	PackageMap* Clone() const
+	{
+		PackageMap* newMap = Create();
+		if (newMap == NULL)
+			return NULL;
+		ObjectDeleter<PackageMap> newMapDeleter(newMap);
+
+		for (BPackageInfoSet::Iterator it(this); it.HasNext();) {
+			const BPackageInfo* info = it.Next();
+			if (newMap->AddNewPackageInfo(*info) != B_OK)
+				return NULL;
+		}
+
+		return newMapDeleter.Detach();
 	}
 
 	void AddPackageInfo(PackageInfo* info)
@@ -98,6 +134,32 @@ struct BPackageInfoSet::PackageMap
 		fCount++;
 	}
 
+	status_t AddNewPackageInfo(const BPackageInfo& oldInfo)
+	{
+		PackageInfo* info = new(std::nothrow) PackageInfo(oldInfo);
+		if (info == NULL)
+			return B_NO_MEMORY;
+		ObjectDeleter<PackageInfo> infoDeleter(info);
+	
+		status_t error = info->InitCheck();
+		if (error != B_OK)
+			return error;
+	
+		AddPackageInfo(infoDeleter.Detach());
+	
+		return B_OK;
+	}
+
+	void DeleteAllPackageInfos()
+	{
+		PackageInfo* info = Clear(true);
+		while (info != NULL) {
+			PackageInfo* next = info->hashNext;
+			info->DeleteList();
+			info = next;
+		}
+	}
+
 	uint32 CountPackageInfos() const
 	{
 		return fCount;
@@ -113,19 +175,20 @@ private:
 
 BPackageInfoSet::Iterator::Iterator()
 	:
-	fSet(NULL),
+	fMap(NULL),
 	fNextInfo(NULL)
 {
 }
 
 
-BPackageInfoSet::Iterator::Iterator(const BPackageInfoSet* set)
+BPackageInfoSet::Iterator::Iterator(const PackageMap* map)
 	:
-	fSet(set),
-	fNextInfo(fSet->fPackageMap->GetIterator().Next())
+	fMap(map),
+	fNextInfo(map->GetIterator().Next())
 {
 }
 
+
 bool
 BPackageInfoSet::Iterator::HasNext() const
 {
@@ -145,7 +208,7 @@ BPackageInfoSet::Iterator::Next()
 		} else {
 			// get next in hash table
 			PackageMap::Iterator iterator
-				= fSet->fPackageMap->GetIterator(fNextInfo->Name());
+				= fMap->GetIterator(fNextInfo->Name());
 			iterator.Next();
 			fNextInfo = iterator.Next();
 		}
@@ -160,64 +223,52 @@ BPackageInfoSet::Iterator::Next()
 
 BPackageInfoSet::BPackageInfoSet()
 	:
-	fPackageMap(new(std::nothrow) PackageMap)
+	fPackageMap(NULL)
 {
 }
 
 
 BPackageInfoSet::~BPackageInfoSet()
 {
-	MakeEmpty();
-	delete fPackageMap;
+	if (fPackageMap != NULL)
+		fPackageMap->ReleaseReference();
+}
+
+
+BPackageInfoSet::BPackageInfoSet(const BPackageInfoSet& other)
+	:
+	fPackageMap(other.fPackageMap)
+{
+	if (fPackageMap != NULL)
+		fPackageMap->AcquireReference();
 }
 
 
 status_t
-BPackageInfoSet::Init()
+BPackageInfoSet::AddInfo(const BPackageInfo& info)
 {
-	return fPackageMap->Init();
-}
-
-
-status_t
-BPackageInfoSet::AddInfo(const BPackageInfo& _info)
-{
-	if (fPackageMap == NULL)
-		return B_NO_INIT;
-
-	PackageInfo* info = new(std::nothrow) PackageInfo(_info);
-	if (info == NULL)
+	if (!_CopyOnWrite())
 		return B_NO_MEMORY;
 
-	status_t error = info->InitCheck();
-	if (error != B_OK) {
-		delete info;
-		return error;
-	}
-
-	if (PackageInfo* oldInfo = fPackageMap->Lookup(info->Name())) {
-		// TODO: Check duplicates?
-		info->listNext = oldInfo->listNext;
-		oldInfo->listNext = info;
-	} else
-		fPackageMap->Insert(info);
-
-	return B_OK;
+	return fPackageMap->AddNewPackageInfo(info);
 }
 
 
 void
 BPackageInfoSet::MakeEmpty()
 {
-	if (fPackageMap == NULL)
+	if (fPackageMap == NULL || fPackageMap->CountPackageInfos() == 0)
 		return;
 
-	PackageInfo* info = fPackageMap->Clear(true);
-	while (info != NULL) {
-		PackageInfo* next = info->hashNext;
-		delete info;
-		info = next;
+	// If our map is shared, just set it to NULL.
+	if (fPackageMap->CountReferences() != 1) {
+		fPackageMap->ReleaseReference();
+		fPackageMap = NULL;
+		return;
 	}
+
+	// Our map is not shared -- make it empty.
+	fPackageMap->DeleteAllPackageInfos();
 }
 
 
@@ -234,7 +285,46 @@ BPackageInfoSet::CountInfos() const
 BPackageInfoSet::Iterator
 BPackageInfoSet::GetIterator() const
 {
-	return Iterator(this);
+	return Iterator(fPackageMap);
+}
+
+
+BPackageInfoSet&
+BPackageInfoSet::operator=(const BPackageInfoSet& other)
+{
+	if (other.fPackageMap == fPackageMap)
+		return *this;
+
+	if (fPackageMap != NULL)
+		fPackageMap->ReleaseReference();
+
+	fPackageMap = other.fPackageMap;
+
+	if (fPackageMap != NULL)
+		fPackageMap->AcquireReference();
+
+	return *this;
+}
+
+
+bool
+BPackageInfoSet::_CopyOnWrite()
+{
+	if (fPackageMap == NULL) {
+		fPackageMap = PackageMap::Create();
+		return fPackageMap != NULL;
+	}
+
+	if (fPackageMap->CountReferences() == 1)
+		return true;
+
+	PackageMap* newMap = fPackageMap->Clone();
+	if (newMap == NULL)
+		return false;
+
+	fPackageMap->ReleaseReference();
+	fPackageMap = newMap;
+	return true;
 }
 
 
diff --git a/src/kits/package/RepositoryCache.cpp b/src/kits/package/RepositoryCache.cpp
index d6f5b2759b..c62c204997 100644
--- a/src/kits/package/RepositoryCache.cpp
+++ b/src/kits/package/RepositoryCache.cpp
@@ -243,15 +243,11 @@ BRepositoryCache::SetTo(const BEntry& entry)
 	fPackages.MakeEmpty();
 	fEntry.Unset();
 
-	// init package info set
-	status_t result = fPackages.Init();
-	if (result != B_OK)
-		return result;
-
 	// get cache file path
 	fEntry = entry;
 
 	BPath repositoryCachePath;
+	status_t result;
 	if ((result = entry.GetPath(&repositoryCachePath)) != B_OK)
 		return result;