WebCrypto: Implement digest() using NSS

content/renderer/webcrypto_digest.h

+// Copyright (c) 2013 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 CONTENT_RENDERER_WEBCRYPTO_DIGEST_H_
+#define CONTENT_RENDERER_WEBCRYPTO_DIGEST_H_
+
+#include "base/compiler_specific.h"
+#include "base/memory/scoped_ptr.h"
+
+#include "third_party/WebKit/public/platform/WebCrypto.h"
+#include "third_party/WebKit/public/platform/WebCryptoAlgorithm.h"
+
+#if defined(USE_NSS)
+typedef struct HASHContextStr HASHContext;
+#endif
+
+namespace content {
+
+class WebCryptoDigest : public WebKit::WebCryptoOperation {
+ public:
+  explicit WebCryptoDigest(const WebKit::WebCryptoOperationResult& result);
+  virtual ~WebCryptoDigest();
+
+  bool Initialize(const WebKit::WebCryptoAlgorithm& algorithm);
+
+  // WebKit::WebCryptoOperation implementation
+  //
+  // Feeds data to the digest operation.
+  //   - |bytes| may be 0 if |size| is 0
+  //   - |bytes| is valid only until process() returns
+  //   - process() will not be called after abort() or finish()
+  virtual void process(const unsigned char* bytes, size_t size);
+  // Cancels the in-process digest operation.
+  virtual void abort();
+  // Indicates that there is no more data to receive.
+  virtual void finish();
+
+ private:
+  WebKit::WebCryptoOperationResult result_;
+
+#if defined(USE_NSS)
+  struct HASHDeleter {
+    void operator()(void* ptr) const;
+  };
+  scoped_ptr<HASHContext, HASHDeleter> context_;

[Ryan Sleevi, 2013/08/13 18:58:16]

style: You should just be able to forward declare HASHDeleter - without having
to declare the functions/type, because the scoped_ptr<> template dtor shouldn't
be instantiated until the .cc file.

BUG? missing DISALLOW_COPY_AND_ASSIGN

I'm not convinced the value of the scoped_ptr<> is all that great here for this
use case. If it was something widely used, I can see scoped_nss_types, but here,
there's only one exit point - seems reasonable to just destroy the hash in the
dtor.

[Bryan Eyler, 2013/08/13 23:24:12]

I get compile-time errors if I try to forward-declare this, so I don't think
it's possible.

For DISALLOW_COPY_AND_ASSIGN, you'd talking about WebCryptoDigest, correct? 
Will add to this class.

Should we just go back to using a normal pointer?  It seemed to produce slightly
simpler and cleaner code.

On 2013/08/13 18:58:16, Ryan Sleevi wrote:

[Ryan Sleevi, 2013/08/13 23:24:47]

Yes
SGTM.

[Bryan Eyler, 2013/08/13 23:34:08]

Done.

+#endif
+};
+
+}  // namespace content
+
+#endif  // CONTENT_RENDERER_WEBCRYPTO_DIGEST_H_