Add methods to query specific entries

Fixes: ironfede#235

OpenMcdf.Tests/StorageTests.cs

@@ -25,6 +25,14 @@ public void OpenStorage(string fileName)
 
         Assert.ThrowsException<DirectoryNotFoundException>(() => rootStorage.OpenStorage(""));
 
+        Assert.IsTrue(rootStorage.ContainsEntry("MyStorage"));
+        Assert.IsFalse(rootStorage.ContainsEntry("NonExistentStorage"));
+
+        bool found = rootStorage.TryGetEntryInfo("MyStorage", out EntryInfo entryInfo);
+        Assert.IsTrue(found);
+        Assert.IsNotNull(entryInfo);
+        Assert.AreEqual("MyStorage", entryInfo.Name);
+
         Storage storage = rootStorage.OpenStorage("MyStorage");
         Assert.AreEqual("MyStorage", storage.EntryInfo.Name);
     }

OpenMcdf/Storage.cs

@@ -86,6 +86,32 @@ IEnumerable<DirectoryEntry> EnumerateDirectoryEntries()
         }
     }
 
+    public bool ContainsEntry(string name)
+    {
+        ThrowHelper.ThrowIfNameIsInvalid(name);
+
+        this.ThrowIfDisposed(Context.IsDisposed);
+
+        return directoryTree.TryGetDirectoryEntry(name, out DirectoryEntry? _);
+    }
+
+    public bool TryGetEntryInfo(string name, out EntryInfo entryInfo)
+    {
+        ThrowHelper.ThrowIfNameIsInvalid(name);
+
+        this.ThrowIfDisposed(Context.IsDisposed);
+
+        if (!directoryTree.TryGetDirectoryEntry(name, out DirectoryEntry? entry))
+        {
+            entryInfo = default;
+            return false;
+        }
+
+        string path = $"{EntryInfo.Path}{EntryInfo.Name}";
+        entryInfo = entry.ToEntryInfo(path);
+        return true;
+    }
+
     DirectoryEntry AddDirectoryEntry(StorageType storageType, string name)
     {
         DirectoryEntry entry = Context.DirectoryEntries.CreateOrRecycleDirectoryEntry();