Abstracts SHA256 context for NSS / OpenSSL.

base/crypto/secure_hash.h

Index: base/crypto/secure_hash.h
diff --git a/base/crypto/secure_hash.h b/base/crypto/secure_hash.h
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index 0000000000000000000000000000000000000000..375921829efdba1407c795a875dce0486c814cc2
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+++ b/base/crypto/secure_hash.h
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+// Copyright (c) 2011 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_CRYPTO_SECURE_HASH_H_
+#define BASE_CRYPTO_SECURE_HASH_H_
+#pragma once
+
+#include "base/basictypes.h"
+
+namespace base {
+
+// A wrapper to calculate secure hashes incrementally, allowing to
+// be used when the full input is not known in advance.
+class SecureHash {
+ public:
+  enum Algorithm {
+    SHA256,
+  };
+  virtual ~SecureHash() {}
+
+  static SecureHash* Create(Algorithm type);
+
+  virtual void Update(const void* input, size_t len) = 0;
+  virtual void Finish(void* output, size_t len) = 0;
+
+ protected:
+  SecureHash() {}
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(SecureHash);
+};
+
+}  // namespace base
+
+#endif  // BASE_CRYPTO_SECURE_HASH_H_