Release native memory in a deterministic way

When functions fail with an exception, they should release any SafeHandle they have used, since they don't return any meaningful value.
chromium · Feb 17, 2020 · fff36a1 · fff36a1
1 parent ca8e2f5
commit fff36a1
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Showing 2 changed files with 29 additions and 14 deletions.
diff --git a/src/Core/Win32/Files/NativeFile.cs b/src/Core/Win32/Files/NativeFile.cs
@@ -48,13 +48,18 @@ private static SafeHeapBlockHandle ReadFileWorker(FullPath path, long fileSize,
         }
         var len = (int)Math.Min(maxLen, fileSize);
         var heap = HeapAllocStatic.Alloc(len + trailingByteCount);
-        var bytesRead = new int[1];
+        try {
+          var bytesRead = new int[1];
 
-        if (!NativeMethods.ReadFile(fileHandle, heap.Pointer, len, bytesRead, null))
-          throw new Win32Exception();
+          if (!NativeMethods.ReadFile(fileHandle, heap.Pointer, len, bytesRead, null))
+            throw new Win32Exception();
 
-        if (bytesRead[0] != len)
-          throw new Exception("File read operation didn't read the whole file");
+          if (bytesRead[0] != len)
+            throw new Exception("File read operation didn't read the whole file");
+        } catch (Exception) {
+          heap.Dispose();
+          throw;
+        }
 
         return heap;
       }

diff --git a/src/Core/Win32/Strings/Conversion.cs b/src/Core/Win32/Strings/Conversion.cs
@@ -26,10 +26,15 @@ public static unsafe SafeHeapBlockHandle Utf8ToUtf16(byte* start, byte* end) {
       var decoder = Encoding.UTF8.GetDecoder();
       var charCount = decoder.GetCharCount(start, byteLength, true);
       var newBlock = HeapAllocStatic.Alloc(charCount * sizeof(char));
-      var result = decoder.GetChars(start, byteLength, (char*)newBlock.Pointer.ToPointer(),
-                                    charCount, true);
-      if (result != charCount) {
-        throw new Exception("Error converting UTF8 string to UTF16 string.");
+      try {
+        var result = decoder.GetChars(start, byteLength, (char*)newBlock.Pointer.ToPointer(),
+                                      charCount, true);
+        if (result != charCount) {
+          throw new Exception("Error converting UTF8 string to UTF16 string.");
+        }
+      } catch (Exception) {
+        newBlock.Dispose();
+        throw;
       }
       return newBlock;
     }
@@ -45,10 +50,15 @@ public static unsafe SafeHeapBlockHandle Utf16ToUtf8(char* start, char* end) {
       var encoder = Encoding.UTF8.GetEncoder();
       var byteCount = encoder.GetByteCount(start, (int)charCount, true);
       var newBlock = HeapAllocStatic.Alloc(byteCount);
-      var result = encoder.GetBytes(start, (int)charCount, (byte*)newBlock.Pointer.ToPointer(),
-                                    byteCount, true);
-      if (result != byteCount) {
-        throw new Exception("Error converting string from UTF16 to UTF8.");
+      try {
+        var result = encoder.GetBytes(start, (int)charCount, (byte*)newBlock.Pointer.ToPointer(),
+                                      byteCount, true);
+        if (result != byteCount) {
+          throw new Exception("Error converting string from UTF16 to UTF8.");
+        }
+      } catch (Exception) {
+        newBlock.Dispose();
+        throw;
       }
       return newBlock;
     }
@@ -57,7 +67,7 @@ public static unsafe SafeHeapBlockHandle StringToUtf8(string value) {
       if (value == null)
         throw new ArgumentException();
 
-      fixed(char* start = value) {
+      fixed (char* start = value) {
         var block = Utf16ToUtf8(start, start + value.Length);
         return block;
       }