Remove kernel_interface.cpp LeafNode dependency

Introduce abstract virtual Node::ReadSymlink() method that is now used
in packagefs_read_symlink() instead of casting to LeafNode.

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

@@ -1,5 +1,5 @@
 /*
- * Copyright 2009, Ingo Weinhold, [email protected].
+ * Copyright 2009-2011, Ingo Weinhold, [email protected].
  * Distributed under the terms of the MIT License.
  */
 
@@ -164,6 +164,13 @@ Directory::Read(io_request* request)
 }
 
 
+status_t
+Directory::ReadSymlink(void* buffer, size_t* bufferSize)
+{
+	return B_IS_A_DIRECTORY;
+}
+
+
 void
 Directory::AddChild(Node* node)
 {

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

@@ -1,5 +1,5 @@
 /*
- * Copyright 2009, Ingo Weinhold, ingo_weinhold@gmx.de.
+ * Copyright 2009-2011, Ingo Weinhold, ingo_weinhold@gmx.de.
  * Distributed under the terms of the MIT License.
  */
 #ifndef DIRECTORY_H
@@ -48,6 +48,9 @@ public:
 									size_t* bufferSize);
 	virtual	status_t			Read(io_request* request);
 
+	virtual	status_t			ReadSymlink(void* buffer,
+									size_t* bufferSize);
+
 			void				AddChild(Node* node);
 			void				RemoveChild(Node* node);
 			Node*				FindChild(const char* name);

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

@@ -1,11 +1,15 @@
 /*
- * Copyright 2009, Ingo Weinhold, ingo_weinhold@gmx.de.
+ * Copyright 2009-2011, Ingo Weinhold, ingo_weinhold@gmx.de.
  * Distributed under the terms of the MIT License.
  */
 
 
 #include "LeafNode.h"
 
+#include <string.h>
+
+#include <algorithm>
+
 #include "Utils.h"
 
 
@@ -168,6 +172,27 @@ LeafNode::Read(io_request* request)
 }
 
 
+status_t
+LeafNode::ReadSymlink(void* buffer, size_t* bufferSize)
+{
+	PackageLeafNode* packageNode = fPackageNodes.Head();
+	if (packageNode == NULL)
+		return B_BAD_VALUE;
+
+	const char* linkPath = packageNode->SymlinkPath();
+	if (linkPath == NULL) {
+		*bufferSize = 0;
+		return B_OK;
+	}
+
+	size_t toCopy = std::min(strlen(linkPath), *bufferSize);
+	memcpy(buffer, linkPath, toCopy);
+	*bufferSize = toCopy;
+
+	return B_OK;
+}
+
+
 const char*
 LeafNode::SymlinkPath() const
 {

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

@@ -1,5 +1,5 @@
 /*
- * Copyright 2009, Ingo Weinhold, ingo_weinhold@gmx.de.
+ * Copyright 2009-2011, Ingo Weinhold, ingo_weinhold@gmx.de.
  * Distributed under the terms of the MIT License.
  */
 #ifndef LEAF_NODE_H
@@ -35,6 +35,9 @@ public:
 									size_t* bufferSize);
 	virtual	status_t			Read(io_request* request);
 
+	virtual	status_t			ReadSymlink(void* buffer,
+									size_t* bufferSize);
+
 			const char*			SymlinkPath() const;
 
 private:

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

@@ -1,5 +1,5 @@
 /*
- * Copyright 2009, Ingo Weinhold, ingo_weinhold@gmx.de.
+ * Copyright 2009-2011, Ingo Weinhold, ingo_weinhold@gmx.de.
  * Distributed under the terms of the MIT License.
  */
 #ifndef NODE_H
@@ -60,6 +60,9 @@ public:
 									size_t* bufferSize) = 0;
 	virtual	status_t			Read(io_request* request) = 0;
 
+	virtual	status_t			ReadSymlink(void* buffer,
+									size_t* bufferSize) = 0;
+
 protected:
 			rw_lock				fLock;
 			ino_t				fID;

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

@@ -21,7 +21,6 @@
 #include "DebugSupport.h"
 #include "Directory.h"
 #include "GlobalFactory.h"
-#include "LeafNode.h"
 #include "PackageFSRoot.h"
 #include "Volume.h"
 
@@ -315,17 +314,7 @@ packagefs_read_symlink(fs_volume* fsVolume, fs_vnode* fsNode, char* buffer,
 	if (!S_ISLNK(node->Mode()))
 		return B_BAD_VALUE;
 
-	const char* linkPath = dynamic_cast<LeafNode*>(node)->SymlinkPath();
+	return node->ReadSymlink(buffer, _bufferSize);
-	if (linkPath == NULL) {
-		*_bufferSize = 0;
-		return B_OK;
-	}
-
-	size_t toCopy = std::min(strlen(linkPath), *_bufferSize);
-	memcpy(buffer, linkPath, toCopy);
-	*_bufferSize = toCopy;
-
-	return B_OK;
 }