From c184849dc3b79d631fb5f279c9868e5a6bc05990 Mon Sep 17 00:00:00 2001
From: Chris Wilson <chris+github@qwirx.com>
Date: Sun, 5 Jul 2009 21:43:57 +0000
Subject: Allow RaidFileWrite to test that the reference count of an object is
 correct before overwriting or deleting it.

---
 lib/raidfile/RaidFileException.txt |  3 +++
 lib/raidfile/RaidFileWrite.cpp     | 52 +++++++++++++++++++++++++++++++++++---
 lib/raidfile/RaidFileWrite.h       |  2 ++
 3 files changed, 54 insertions(+), 3 deletions(-)

(limited to 'lib/raidfile')

diff --git a/lib/raidfile/RaidFileException.txt b/lib/raidfile/RaidFileException.txt
index c69dc2a2..c7ddfcc5 100644
--- a/lib/raidfile/RaidFileException.txt
+++ b/lib/raidfile/RaidFileException.txt
@@ -23,3 +23,6 @@ CanOnlyGetUsageBeforeCommit		19
 CanOnlyGetFileSizeBeforeCommit	20
 ErrorOpeningWriteFileOnTruncate	21
 FileIsCurrentlyOpenForWriting	22
+RequestedModifyUnreferencedFile	23	Internal error: the server attempted to modify a file which has no references.
+RequestedModifyMultiplyReferencedFile	24	Internal error: the server attempted to modify a file which has multiple references.
+RequestedDeleteReferencedFile	25	Internal error: the server attempted to delete a file which is still referenced.
diff --git a/lib/raidfile/RaidFileWrite.cpp b/lib/raidfile/RaidFileWrite.cpp
index 00067f72..2d852f86 100644
--- a/lib/raidfile/RaidFileWrite.cpp
+++ b/lib/raidfile/RaidFileWrite.cpp
@@ -42,17 +42,47 @@
 //
 // Function
 //		Name:    RaidFileWrite::RaidFileWrite(int, const std::string &)
-//		Purpose: Construtor, just stores requried details
+//		Purpose: Simple constructor, just stores required details
 //		Created: 2003/07/10
 //
 // --------------------------------------------------------------------------
 RaidFileWrite::RaidFileWrite(int SetNumber, const std::string &Filename)
 	: mSetNumber(SetNumber),
 	  mFilename(Filename),
-	  mOSFileHandle(-1)		// not valid file handle
+	  mOSFileHandle(-1), // not valid file handle
+	  mRefCount(-1) // unknown refcount
 {
 }
 
+// --------------------------------------------------------------------------
+//
+// Function
+//		Name:    RaidFileWrite::RaidFileWrite(int,
+//			 const std::string &, int refcount)
+//		Purpose: Constructor with check for overwriting file
+//			 with multiple references
+//		Created: 2009/07/05
+//
+// --------------------------------------------------------------------------
+RaidFileWrite::RaidFileWrite(int SetNumber, const std::string &Filename,
+	int refcount)
+	: mSetNumber(SetNumber),
+	  mFilename(Filename),
+	  mOSFileHandle(-1),		// not valid file handle
+	  mRefCount(refcount)
+{
+	// Can't check for zero refcount here, because it's legal
+	// to create a RaidFileWrite to delete an object with zero refcount.
+	// Check in Commit() and Delete() instead.
+	if (refcount > 1)
+	{
+		BOX_ERROR("Attempted to modify object " << mFilename <<
+			", which has " << refcount << " references");
+		THROW_EXCEPTION(RaidFileException,
+			RequestedModifyMultiplyReferencedFile);
+	}
+}
+
 // --------------------------------------------------------------------------
 //
 // Function
@@ -250,7 +280,15 @@ void RaidFileWrite::Commit(bool ConvertToRaidNow)
 	{
 		THROW_EXCEPTION(RaidFileException, NotOpen)
 	}
-	
+
+	if (mRefCount == 0)
+	{
+		BOX_ERROR("Attempted to modify object " << mFilename << 
+			", which has no references");
+		THROW_EXCEPTION(RaidFileException,
+			RequestedModifyUnreferencedFile);
+	}
+
 	// Rename it into place -- BEFORE it's closed so lock remains
 
 #ifdef WIN32
@@ -638,6 +676,14 @@ void RaidFileWrite::TransformToRaidStorage()
 // --------------------------------------------------------------------------
 void RaidFileWrite::Delete()
 {
+	if (mRefCount != 0 && mRefCount != -1)
+	{
+		BOX_ERROR("Attempted to delete object " << mFilename <<
+			" which has " << mRefCount << " references");
+		THROW_EXCEPTION(RaidFileException,
+			RequestedDeleteReferencedFile);
+	}
+
 	// Get disc set
 	RaidFileController &rcontroller(RaidFileController::GetController());
 	RaidFileDiscSet rdiscSet(rcontroller.GetDiscSet(mSetNumber));
diff --git a/lib/raidfile/RaidFileWrite.h b/lib/raidfile/RaidFileWrite.h
index d7e51f21..418f90ee 100644
--- a/lib/raidfile/RaidFileWrite.h
+++ b/lib/raidfile/RaidFileWrite.h
@@ -28,6 +28,7 @@ class RaidFileWrite : public IOStream
 {
 public:
 	RaidFileWrite(int SetNumber, const std::string &Filename);
+	RaidFileWrite(int SetNumber, const std::string &Filename, int refcount);
 	~RaidFileWrite();
 private:
 	RaidFileWrite(const RaidFileWrite &rToCopy);
@@ -60,6 +61,7 @@ private:
 	int mSetNumber;
 	std::string mFilename;
 	int mOSFileHandle;
+	int mRefCount;
 };
 
 #endif // RAIDFILEWRITE__H
-- 
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