Simplify disposal of some resources

Author: nulltoken

LibGit2Sharp/Core/Handles/DisposableExtensions.cs

@@ -0,0 +1,17 @@
+using System;
+
+namespace LibGit2Sharp.Core.Handles
+{
+    internal static class DisposableExtensions
+    {
+        public static void SafeDispose(this IDisposable disposable)
+        {
+            if (disposable == null)
+            {
+                return;
+            }
+
+            disposable.Dispose();
+        }
+    }
+}

LibGit2Sharp/Core/Handles/SafeHandleExtensions.cs

@@ -2965,8 +2965,7 @@ private static IEnumerable<TResult> git_iterator_next<TIterator, THandle, TPaylo
                 }
                 finally
                 {
-                    if (next != null)
-                        next.SafeDispose();
+                    next.SafeDispose();
                 }
             }
         }

LibGit2Sharp/Core/Proxy.cs

@@ -292,23 +292,12 @@ private static TreeComparisonHandleRetriever WorkdirAndIndexToTree(Repository re
         {
             TreeComparisonHandleRetriever comparisonHandleRetriever = (oh, nh, o) =>
             {
-                DiffSafeHandle diff = null, diff2 = null;
+                DiffSafeHandle diff = Proxy.git_diff_tree_to_index(repo.Handle, repo.Index.Handle, oh, o);
 
-                try
+                using (DiffSafeHandle diff2 = Proxy.git_diff_index_to_workdir(repo.Handle, repo.Index.Handle, o))
                 {
-                    diff = Proxy.git_diff_tree_to_index(repo.Handle, repo.Index.Handle, oh, o);
-                    diff2 = Proxy.git_diff_index_to_workdir(repo.Handle, repo.Index.Handle, o);
                     Proxy.git_diff_merge(diff, diff2);
                 }
-                catch
-                {
-                    diff.SafeDispose();
-                    throw;
-                }
-                finally
-                {
-                    diff2.SafeDispose();
-                }
 
                 return diff;
             };
@@ -332,17 +321,9 @@ private DiffSafeHandle BuildDiffList(ObjectId oldTreeId, ObjectId newTreeId, Tre
             {
                 var diffList = comparisonHandleRetriever(oldTreeId, newTreeId, options);
 
-                try
-                {
-                    if (explicitPathsOptions != null)
-                    {
-                        DispatchUnmatchedPaths(explicitPathsOptions, filePaths, matchedPaths);
-                    }
-                }
-                catch
+                if (explicitPathsOptions != null)
                 {
-                    diffList.Dispose();
-                    throw;
+                    DispatchUnmatchedPaths(explicitPathsOptions, filePaths, matchedPaths);
                 }
 
                 DetectRenames(diffList, compareOptions);

LibGit2Sharp/Diff.cs

@@ -83,6 +83,7 @@
     <Compile Include="Core\GitCheckoutOptsWrapper.cs" />
     <Compile Include="Core\GitCredentialType.cs" />
     <Compile Include="Core\GitRevertOpts.cs" />
+    <Compile Include="Core\Handles\DisposableExtensions.cs" />
     <Compile Include="Core\Handles\PatchSafeHandle.cs" />
     <Compile Include="Core\IntPtrExtensions.cs" />
     <Compile Include="DefaultCredentials.cs" />
@@ -258,7 +259,6 @@
     <Compile Include="FileStatus.cs" />
     <Compile Include="Core\GitTime.cs" />
     <Compile Include="Core\NativeMethods.cs" />
-    <Compile Include="Core\Handles\SafeHandleExtensions.cs" />
     <Compile Include="Core\ObjectSafeWrapper.cs" />
     <Compile Include="Core\Handles\RemoteSafeHandle.cs" />
     <Compile Include="Core\Handles\RevWalkerSafeHandle.cs">

LibGit2Sharp/LibGit2Sharp.csproj

@@ -440,23 +440,15 @@ internal GitObject LookupInternal(ObjectId id, GitObjectType type, FilePath know
         {
             Ensure.ArgumentNotNull(id, "id");
 
-            GitObjectSafeHandle obj = null;
-
-            try
+            using (GitObjectSafeHandle obj = Proxy.git_object_lookup(handle, id, type))
             {
-                obj = Proxy.git_object_lookup(handle, id, type);
-
                 if (obj == null)
                 {
                     return null;
                 }
 
                 return GitObject.BuildFrom(this, id, Proxy.git_object_type(obj), knownPath);
             }
-            finally
-            {
-                obj.SafeDispose();
-            }
         }
 
         private static string PathFromRevparseSpec(string spec)