Improve argument/state validation

OpenMcdf.Tests/RootStorageTests.cs

@@ -5,15 +5,27 @@ public sealed class RootStorageTests
 {
     [TestMethod]
     [DoNotParallelize] // Test sharing
-    [DataRow("MultipleStorage.cfs")]
+    [DataRow("TestStream_v3_0.cfs")]
     public void Open(string fileName)
     {
         using var rootStorage = RootStorage.OpenRead(fileName);
         using var rootStorage2 = RootStorage.OpenRead(fileName);
 
         Assert.ThrowsException<IOException>(() => RootStorage.Open(fileName, FileMode.Open));
         Assert.ThrowsException<IOException>(() => RootStorage.Open(fileName, FileMode.Open, FileAccess.ReadWrite));
-        Assert.ThrowsException<IOException>(() => RootStorage.OpenWrite(fileName));
+
+        using CfbStream stream = rootStorage.OpenStream("TestStream");
+        Assert.ThrowsException<NotSupportedException>(() => stream.WriteByte(0));
+
+        Assert.ThrowsException<NotSupportedException>(() => rootStorage.CreateStream("TestStream2"));
+        Assert.ThrowsException<NotSupportedException>(() => rootStorage.CreateStorage("TestStream2"));
+        Assert.ThrowsException<NotSupportedException>(() => rootStorage.Delete("TestStream"));
+        Assert.ThrowsException<NotSupportedException>(() => rootStorage.Commit());
+        Assert.ThrowsException<NotSupportedException>(() => rootStorage.Revert());
+        Assert.ThrowsException<NotSupportedException>(() => rootStorage.CreationTime = DateTime.MinValue);
+        Assert.ThrowsException<NotSupportedException>(() => rootStorage.ModifiedTime = DateTime.MinValue);
+        Assert.ThrowsException<NotSupportedException>(() => rootStorage.CLISD = Guid.Empty);
+        Assert.ThrowsException<NotSupportedException>(() => rootStorage.StateBits = 0);
     }
 
     [TestMethod]

OpenMcdf.Tests/StreamTests.cs

@@ -20,7 +20,7 @@ public void OpenStream(string fileName)
 
         Assert.ThrowsException<FileNotFoundException>(() => rootStorage.OpenStream(""));
 
-        CfbStream stream = rootStorage.OpenStream("TestStream");
+        using CfbStream stream = rootStorage.OpenStream("TestStream");
         Assert.AreEqual("TestStream", stream.EntryInfo.Name);
     }
 

OpenMcdf/RootContext.cs

@@ -1,4 +1,6 @@
-namespace OpenMcdf;
+using System.Diagnostics.CodeAnalysis;
+
+namespace OpenMcdf;
 
 enum IOContextFlags
 {
@@ -152,6 +154,20 @@ public void Dispose()
         }
     }
 
+    [MemberNotNull(nameof(writer))]
+    public void ThrowIfNotWritable()
+    {
+        if (writer is null)
+            throw new NotSupportedException("Root storage is not writable.");
+    }
+
+    [MemberNotNull(nameof(transactedStream))]
+    public void ThrowIfNotTransacted()
+    {
+        if (transactedStream is null)
+            throw new NotSupportedException("Cannot commit non-transacted storage.");
+    }
+
     public void Flush()
     {
         Fat.Flush();
@@ -181,8 +197,8 @@ public void WriteHeader()
 
     public void Commit()
     {
-        if (writer is null || transactedStream is null)
-            throw new InvalidOperationException("Cannot commit non-transacted storage.");
+        ThrowIfNotWritable();
+        ThrowIfNotTransacted();
 
         miniStream?.Flush();
         miniFat?.Flush();
@@ -194,8 +210,7 @@ public void Commit()
 
     public void Revert()
     {
-        if (writer is null || transactedStream is null)
-            throw new InvalidOperationException("Cannot revert non-transacted storage.");
+        ThrowIfNotTransacted();
 
         transactedStream.Revert();
     }

OpenMcdf/RootStorage.cs

@@ -24,6 +24,18 @@ public sealed class RootStorage : Storage, IDisposable
 {
     readonly StorageModeFlags storageModeFlags;
 
+    private static void ThrowIfInvalid(FileMode mode)
+    {
+        if (mode is FileMode.Append)
+            throw new ArgumentException("Append mode is not valid for compound files.", nameof(mode));
+    }
+
+    private static void ThrowIfInvalid(FileAccess access)
+    {
+        if (access is FileAccess.Write)
+            throw new ArgumentException("Write-only access is not valid for compound files.", nameof(access));
+    }
+
     private static void ThrowIfLeaveOpen(StorageModeFlags flags)
     {
         if (flags.HasFlag(StorageModeFlags.LeaveOpen))
@@ -64,6 +76,7 @@ public static RootStorage Create(Stream stream, Version version = Version.V3, St
 
     public static RootStorage Open(string fileName, FileMode mode, StorageModeFlags flags = StorageModeFlags.None)
     {
+        ThrowIfInvalid(mode);
         ThrowIfLeaveOpen(flags);
 
         FileStream stream = File.Open(fileName, mode);
@@ -72,6 +85,8 @@ public static RootStorage Open(string fileName, FileMode mode, StorageModeFlags
 
     public static RootStorage Open(string fileName, FileMode mode, FileAccess access, StorageModeFlags flags = StorageModeFlags.None)
     {
+        ThrowIfInvalid(mode);
+        ThrowIfInvalid(access);
         ThrowIfLeaveOpen(flags);
 
         FileStream stream = File.Open(fileName, mode, access);
@@ -97,14 +112,6 @@ public static RootStorage OpenRead(string fileName, StorageModeFlags flags = Sto
         return Open(stream, flags);
     }
 
-    public static RootStorage OpenWrite(string fileName, StorageModeFlags flags = StorageModeFlags.None)
-    {
-        ThrowIfLeaveOpen(flags);
-
-        FileStream stream = File.OpenWrite(fileName);
-        return Open(stream, flags);
-    }
-
     RootStorage(RootContextSite rootContextSite, StorageModeFlags storageModeFlags)
         : base(rootContextSite, rootContextSite.Context.RootEntry, null)
     {

OpenMcdf/Storage.cs

@@ -32,6 +32,8 @@ public Guid CLISD
         get => directoryEntry.CLSID;
         set
         {
+            Context.ThrowIfNotWritable();
+
             directoryEntry.CLSID = value;
             Context.DirectoryEntries.Write(directoryEntry);
         }
@@ -42,6 +44,8 @@ public DateTime CreationTime
         get => directoryEntry.CreationTime;
         set
         {
+            Context.ThrowIfNotWritable();
+
             directoryEntry.CreationTime = value;
             Context.DirectoryEntries.Write(directoryEntry);
         }
@@ -52,6 +56,8 @@ public DateTime ModifiedTime
         get => directoryEntry.ModifiedTime;
         set
         {
+            Context.ThrowIfNotWritable();
+
             directoryEntry.ModifiedTime = value;
             Context.DirectoryEntries.Write(directoryEntry);
         }
@@ -62,6 +68,8 @@ public uint StateBits
         get => directoryEntry.StateBits;
         set
         {
+            Context.ThrowIfNotWritable();
+
             directoryEntry.StateBits = value;
             Context.DirectoryEntries.Write(directoryEntry);
         }
@@ -125,6 +133,7 @@ public Storage CreateStorage(string name)
         ThrowHelper.ThrowIfNameIsInvalid(name);
 
         this.ThrowIfDisposed(Context.IsDisposed);
+        Context.ThrowIfNotWritable();
 
         DirectoryEntry entry = AddDirectoryEntry(StorageType.Storage, name);
         return new Storage(ContextSite, entry, this);
@@ -135,6 +144,7 @@ public CfbStream CreateStream(string name)
         ThrowHelper.ThrowIfNameIsInvalid(name);
 
         this.ThrowIfDisposed(Context.IsDisposed);
+        Context.ThrowIfNotWritable();
 
         DirectoryEntry entry = AddDirectoryEntry(StorageType.Stream, name);
         return new CfbStream(ContextSite, entry, this);
@@ -207,6 +217,7 @@ public void Delete(string name)
         ThrowHelper.ThrowIfNameIsInvalid(name);
 
         this.ThrowIfDisposed(Context.IsDisposed);
+        Context.ThrowIfNotWritable();
 
         directoryTree.TryGetDirectoryEntry(name, out DirectoryEntry? entry);
         if (entry is null)

OpenMcdf/StreamExtensions.cs

@@ -36,7 +36,9 @@ public static int ReadByteCore(this Stream stream)
 
     public static void WriteByteCore(this Stream stream, byte value)
     {
-        ReadOnlySpan<byte> bytes = stackalloc byte[] { value };
+        stream.ThrowIfNotWritable();
+
+        ReadOnlySpan<byte> bytes = [value];
         stream.Write(bytes);
     }
 

StructuredStorageExplorer/MainForm.cs

@@ -142,7 +142,7 @@ private void LoadFile(string fileName)
             cf = null;
 
             // Load file
-            cf = RootStorage.OpenWrite(fileName);
+            cf = RootStorage.Open(fileName, FileMode.Open);
 
             fileNameLabel.Text = fileName;
             saveAsToolStripMenuItem.Enabled = true;