Abstracts SHA256 context for NSS / OpenSSL.

base/secure_hash.h

+// Copyright (c) 2006-2008 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef BASE_SECURE_HASH_H_
+#define BASE_SECURE_HASH_H_
+#pragma once
+
+#include <string>
+
+#include "base/basictypes.h"
+#include "base/sha2.h"

[wtc, 2011/01/25 19:06:43]

This file should not need to include the header for any
specific hash algorithm.

[bulach, 2011/01/25 20:33:41]

Done.

+
+namespace base {
+
+// A wrapper for calculating secure hashes when the full string is not known in
+// advance.

[wtc, 2011/01/25 19:06:43]

Remove "when the full string is not known in advance", which
implies it can only be used when the full string is not known
in advance.

Or you can reword it to remove that confusion.  Please change
"full string" to "full input".

[bulach, 2011/01/25 20:33:41]

I rewrote the sentence, please let me know if it's any clearer.

+class SecureHash {
+ public:
+  enum Type {

[wtc, 2011/01/25 19:06:43]

This enum should be named Algorithm.  The constant can be
named ALG_SHA256 or just SHA256.

[bulach, 2011/01/25 20:33:41]

Done.

+    TYPE_SHA256,
+  };
+  virtual ~SecureHash() {}
+
+  static SecureHash* Create(Type type);
+
+  virtual void Update(const std::string& str) = 0;
+  virtual void Finish(void* output, size_t len) = 0;
+
+ protected:
+  SecureHash() {}
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(SecureHash);
+};
+
+}  // namespace base
+
+#endif  // BASE_SECURE_HASH_H_