Add package link directories to system volume

* Add PackageLinksListener interface. It is used by
  PackageLink[s]Directory to notify a listener about changes.
* Volume does now implement PackageLinksListener and recursively adds/
  removes package link directories.

This makes the package link directories appear at least. They are still
empty.

src/add-ons/kernel/file_systems/packagefs/Jamfile

@@ -25,6 +25,7 @@ HAIKU_PACKAGE_FS_SOURCES =
 	PackageLeafNode.cpp
 	PackageLinkDirectory.cpp
 	PackageLinksDirectory.cpp
+	PackageLinksListener.cpp
 	PackageNode.cpp
 	PackageNodeAttribute.cpp
 	PackageSymlink.cpp

src/add-ons/kernel/file_systems/packagefs/PackageLinkDirectory.cpp

@@ -10,6 +10,7 @@
 
 #include "EmptyAttributeDirectoryCookie.h"
 #include "DebugSupport.h"
+#include "PackageLinksListener.h"
 #include "Utils.h"
 #include "Version.h"
 
@@ -60,7 +61,7 @@ PackageLinkDirectory::Init(Directory* parent, Package* package)
 		RETURN_ERROR(error);
 
 	// add the package
-	AddPackage(package);
+	AddPackage(package, NULL);
 
 	return B_OK;
 }
@@ -131,21 +132,40 @@ PackageLinkDirectory::OpenAttribute(const char* name, int openMode,
 
 
 void
-PackageLinkDirectory::AddPackage(Package* package)
+PackageLinkDirectory::AddPackage(Package* package,
+	PackageLinksListener* listener)
 {
+	NodeWriteLocker writeLocker(this);
+
+	if (listener != NULL)
+		listener->PackageLinkDirectoryRemoved(this);
+
 	// TODO: Add in priority order!
 	fPackages.Add(package);
 	package->SetLinkDirectory(this);
+
+	if (listener != NULL)
+		listener->PackageLinkDirectoryAdded(this);
+	// TODO: The notifications should only happen as necessary!
 }
 
 
 void
-PackageLinkDirectory::RemovePackage(Package* package)
+PackageLinkDirectory::RemovePackage(Package* package,
+	PackageLinksListener* listener)
 {
-
 	ASSERT(package->LinkDirectory() == this);
 
+	NodeWriteLocker writeLocker(this);
+
+	if (listener != NULL)
+		listener->PackageLinkDirectoryRemoved(this);
+
 	package->SetLinkDirectory(NULL);
 	fPackages.Remove(package);
 	// TODO: Check whether that was the top priority package!
+
+	if (listener != NULL && !IsEmpty())
+		listener->PackageLinkDirectoryAdded(this);
+	// TODO: The notifications should only happen as necessary!
 }

src/add-ons/kernel/file_systems/packagefs/PackageLinkDirectory.h

@@ -10,6 +10,9 @@
 #include "Package.h"
 
 
+class PackageLinksListener;
+
+
 class PackageLinkDirectory : public Directory {
 public:
 								PackageLinkDirectory();
@@ -29,8 +32,10 @@ public:
 	virtual	status_t			OpenAttribute(const char* name, int openMode,
 									AttributeCookie*& _cookie);
 
-			void				AddPackage(Package* package);
+			void				AddPackage(Package* package,
-			void				RemovePackage(Package* package);
+									PackageLinksListener* listener);
+			void				RemovePackage(Package* package,
+									PackageLinksListener* listener);
 
 			bool				IsEmpty() const
 									{ return fPackages.IsEmpty(); }

src/add-ons/kernel/file_systems/packagefs/PackageLinksDirectory.cpp

@@ -11,12 +11,14 @@
 #include "EmptyAttributeDirectoryCookie.h"
 #include "DebugSupport.h"
 #include "PackageLinkDirectory.h"
+#include "PackageLinksListener.h"
 #include "Utils.h"
 
 
 PackageLinksDirectory::PackageLinksDirectory()
 	:
-	Directory(0)
+	Directory(0),
+	fListener(NULL)
 		// the ID needs to be assigned later, when added to a volume
 {
 	get_real_time(fModifiedTime);
@@ -111,18 +113,26 @@ PackageLinksDirectory::AddPackage(Package* package)
 	// add the link directory
 	NodeWriteLocker writeLocker(this);
 	if (Node* child = FindChild(linkDirectory->Name())) {
+		// There already is an entry with the name.
 		PackageLinkDirectory* otherLinkDirectory
 			= dynamic_cast<PackageLinkDirectory*>(child);
 		if (otherLinkDirectory != NULL)
 			RETURN_ERROR(B_BAD_VALUE);
 
-		linkDirectory->RemovePackage(package);
+		// There's already a package link directory. Delete the one we created
+		// and add the package to the pre-existing one.
+		linkDirectory->RemovePackage(package, NULL);
 		linkDirectory = otherLinkDirectory;
-		linkDirectory->AddPackage(package);
+		linkDirectory->AddPackage(package, fListener);
-	} else
+	} else {
+		// No entry is in the way, so just add the link directory.
 		AddChild(linkDirectory);
 
-// TODO:...
+		if (fListener != NULL) {
+			NodeWriteLocker linkDirectoryWriteLocker(linkDirectory);
+			fListener->PackageLinkDirectoryAdded(linkDirectory);
+		}
+	}
 
 	return B_OK;
 }
@@ -140,12 +150,10 @@ PackageLinksDirectory::RemovePackage(Package* package)
 
 	NodeWriteLocker writeLocker(this);
 
-	linkDirectory->RemovePackage(package);
+	linkDirectory->RemovePackage(package, fListener);
 
 	// if empty, remove the link directory itself
 	if (linkDirectory->IsEmpty())
 		RemoveChild(linkDirectory);
-
-// TODO:...
 }
 

src/add-ons/kernel/file_systems/packagefs/PackageLinksDirectory.h

@@ -10,6 +10,7 @@
 
 
 class Package;
+class PackageLinksListener;
 
 
 class PackageLinksDirectory : public Directory {
@@ -30,11 +31,15 @@ public:
 	virtual	status_t			OpenAttribute(const char* name, int openMode,
 									AttributeCookie*& _cookie);
 
+			void				SetListener(PackageLinksListener* listener)
+									{ fListener = listener; }
+
 			status_t			AddPackage(Package* package);
 			void				RemovePackage(Package* package);
 
 private:
 			timespec			fModifiedTime;
+			PackageLinksListener* fListener;
 };
 
 

src/add-ons/kernel/file_systems/packagefs/PackageLinksListener.cpp

@@ -0,0 +1,13 @@
+/*
+ * Copyright 2011, Ingo Weinhold, ingo_weinhold@gmx.de.
+ * Distributed under the terms of the MIT License.
+ */
+
+
+#include "PackageLinksListener.h"
+
+
+
+PackageLinksListener::~PackageLinksListener()
+{
+}

src/add-ons/kernel/file_systems/packagefs/PackageLinksListener.h

@@ -0,0 +1,23 @@
+/*
+ * Copyright 2011, Ingo Weinhold, ingo_weinhold@gmx.de.
+ * Distributed under the terms of the MIT License.
+ */
+#ifndef PACKAGE_LINKS_LISTENER_H
+#define PACKAGE_LINKS_LISTENER_H
+
+
+class PackageLinkDirectory;
+
+
+class PackageLinksListener {
+public:
+	virtual						~PackageLinksListener();
+
+	virtual	void				PackageLinkDirectoryAdded(
+										PackageLinkDirectory* directory) = 0;
+	virtual	void				PackageLinkDirectoryRemoved(
+										PackageLinkDirectory* directory) = 0;
+};
+
+
+#endif	// PACKAGE_LINKS_LISTENER_H

src/add-ons/kernel/file_systems/packagefs/Volume.cpp

@@ -35,6 +35,7 @@
 #include "PackageDirectory.h"
 #include "PackageFile.h"
 #include "PackageFSRoot.h"
+#include "PackageLinkDirectory.h"
 #include "PackageLinksDirectory.h"
 #include "PackageSymlink.h"
 #include "Resolvable.h"
@@ -619,6 +620,20 @@ Volume::AddPackageDomain(const char* path)
 }
 
 
+void
+Volume::PackageLinkDirectoryAdded(PackageLinkDirectory* directory)
+{
+	_AddPackageLinksNode(directory);
+}
+
+
+void
+Volume::PackageLinkDirectoryRemoved(PackageLinkDirectory* directory)
+{
+	_RemovePackageLinksNode(directory);
+}
+
+
 /*static*/ status_t
 Volume::_PackageLoaderEntry(void* data)
 {
@@ -734,6 +749,7 @@ Volume::_AddPackageDomain(PackageDomain* domain, bool notify)
 	}
 
 	// add the packages to the node tree
+	VolumeWriteLocker systemVolumeLocker(_SystemVolumeIfNotSelf());
 	VolumeWriteLocker volumeLocker(this);
 	for (PackageFileNameHashTable::Iterator it
 			= domain->Packages().GetIterator(); Package* package = it.Next();) {
@@ -1216,6 +1232,7 @@ Volume::_DomainEntryCreated(PackageDomain* domain, dev_t deviceID,
 	if (error != B_OK)
 		return;
 
+	VolumeWriteLocker systemVolumeLocker(_SystemVolumeIfNotSelf());
 	VolumeWriteLocker volumeLocker(this);
 	domain->AddPackage(package);
 
@@ -1244,6 +1261,7 @@ Volume::_DomainEntryRemoved(PackageDomain* domain, dev_t deviceID,
 	BReference<Package> packageReference(package);
 
 	// remove the package
+	VolumeWriteLocker systemVolumeLocker(_SystemVolumeIfNotSelf());
 	VolumeWriteLocker volumeLocker(this);
 	_RemovePackageContent(package, NULL, true);
 	domain->RemovePackage(package);
@@ -1388,12 +1406,12 @@ Volume::_AddPackageLinksDirectory()
 	NodeWriteLocker rootDirectoryWriteLocker(fRootDirectory);
 	NodeWriteLocker packageLinksDirectoryWriteLocker(packageLinksDirectory);
 
-	packageLinksDirectory->SetID(fNextNodeID++);
 	packageLinksDirectory->SetParent(fRootDirectory);
-
 	fRootDirectory->AddChild(packageLinksDirectory);
-	fNodes.Insert(packageLinksDirectory);
+
-	packageLinksDirectory->AcquireReference();
+	_AddPackageLinksNode(packageLinksDirectory);
+
+	packageLinksDirectory->SetListener(this);
 
 	return B_OK;
 }
@@ -1410,7 +1428,54 @@ Volume::_RemovePackageLinksDirectory()
 	NodeWriteLocker packageLinksDirectoryWriteLocker(packageLinksDirectory);
 
 	if (packageLinksDirectory->Parent() == fRootDirectory) {
-		_RemoveNode(packageLinksDirectory);
+		packageLinksDirectory->SetListener(NULL);
+		_RemovePackageLinksNode(packageLinksDirectory);
 		packageLinksDirectory->SetParent(NULL);
 	}
 }
+
+
+void
+Volume::_AddPackageLinksNode(Node* node)
+{
+	node->SetID(fNextNodeID++);
+
+	fNodes.Insert(node);
+	node->AcquireReference();
+
+	// If this is a directory, recursively add descendants. The directory tree
+	// for the package links isn't deep, so we can do recursion.
+	if (Directory* directory = dynamic_cast<Directory*>(node)) {
+		for (Node* child = directory->FirstChild(); child != NULL;
+				child = directory->NextChild(child)) {
+			NodeWriteLocker childWriteLocker(child);
+			_AddPackageLinksNode(child);
+		}
+	}
+}
+
+
+void
+Volume::_RemovePackageLinksNode(Node* node)
+{
+	// If this is a directory, recursively remove descendants. The directory
+	// tree for the package links isn't deep, so we can do recursion.
+	if (Directory* directory = dynamic_cast<Directory*>(node)) {
+		for (Node* child = directory->FirstChild(); child != NULL;
+				child = directory->NextChild(child)) {
+			NodeWriteLocker childWriteLocker(child);
+			_RemovePackageLinksNode(child);
+		}
+	}
+
+	_RemoveNode(node);
+}
+
+
+inline Volume*
+Volume::_SystemVolumeIfNotSelf() const
+{
+	if (Volume* systemVolume = fPackageFSRoot->SystemVolume())
+		return systemVolume == this ? NULL : systemVolume;
+	return NULL;
+}

src/add-ons/kernel/file_systems/packagefs/Volume.h

@@ -16,6 +16,7 @@
 
 #include "Node.h"
 #include "PackageDomain.h"
+#include "PackageLinksListener.h"
 
 
 class Directory;
@@ -32,7 +33,8 @@ enum MountType {
 };
 
 
-class Volume : public DoublyLinkedListLinkImpl<Volume> {
+class Volume : public DoublyLinkedListLinkImpl<Volume>,
+	private PackageLinksListener {
 public:
 								Volume(fs_volume* fsVolume);
 								~Volume();
@@ -72,6 +74,13 @@ public:
 
 			status_t			AddPackageDomain(const char* path);
 
+private:
+	// PackageLinksListener
+	virtual	void				PackageLinkDirectoryAdded(
+										PackageLinkDirectory* directory);
+	virtual	void				PackageLinkDirectoryRemoved(
+										PackageLinkDirectory* directory);
+
 private:
 			struct Job;
 			struct AddPackageDomainJob;
@@ -147,6 +156,10 @@ private:
 
 			status_t			_AddPackageLinksDirectory();
 			void				_RemovePackageLinksDirectory();
+			void				_AddPackageLinksNode(Node* node);
+			void				_RemovePackageLinksNode(Node* node);
+
+	inline	Volume*				_SystemVolumeIfNotSelf() const;
 
 private:
 	mutable	rw_lock				fLock;