WebCrypto: Add framework for AlgorithmIdentifier normalization.

public/platform/WebCryptoAlgorithm.h

+/*
+ * Copyright (C) 2013 Google Inc. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
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+ * notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above
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+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef WebCryptoAlgorithm_h
+#define WebCryptoAlgorithm_h
+
+#include "WebCommon.h"
+#include "WebPrivatePtr.h"
+
+#if WEBKIT_IMPLEMENTATION
+#include "wtf/PassOwnPtr.h"
+#endif
+
+namespace WebKit {
+
+// The possible algorithm names.

[abarth-chromium, 2013/07/02 06:46:36]

These aren't algorithm names.  They're algorithm IDs.  I'd probably just remove
this comment since it's not correct and redundant with the code.

[eroman, 2013/07/02 08:12:27]

Done.

+enum WebCryptoAlgorithmId {

[eroman, 2013/07/02 06:06:53]

Note: I only included a few algorithms and parameter types in this CL to keep
things simple (and minimally testable).

I will be adding the others incrementally as follow-ups once we have settled on
the approach.

+    AesCbc,

[abarth-chromium, 2013/07/02 06:46:36]

The pattern we use for these API enums is to repeat the name of the enum in the
values:

WebCryptoAlgorithmIdAesCbc

I realize that it's a mouthful, but we do that to avoid naming conflicts.

+    Sha1,
+    Sha224,
+    Sha256,
+    Sha384,
+    Sha512,
+#if WEBKIT_IMPLEMENTATION
+    NumAlgorithmId,
+#endif
+};
+
+// The possible algorithm-specific parameters.

[abarth-chromium, 2013/07/02 06:46:36]

Please omit this redundant comment.

[eroman, 2013/07/02 08:12:27]

Done.

+enum WebCryptoAlgorithmParamsType {
+    NoParams,
+    AesCbcParams,
+    AesKeyGenParams,
+};
+
+// Forward declaration for the algorithm parameters types.

[abarth-chromium, 2013/07/02 06:46:36]

Please omit this comment that just says what the code does.  We know these are
forward declarations.

[eroman, 2013/07/02 08:12:27]

Done.

+class WebCryptoAesCbcParams;
+class WebCryptoAesKeyGenParams;
+
+class WebCryptoAlgorithmParams;
+class WebCryptoAlgorithmPrivate;
+
+// The WebCryptoAlgorithm represents a normalized algorithm and its parameters.
+//   * Immutable
+//   * Threadsafe
+//   * Copiable (cheaply)

[abarth-chromium, 2013/07/02 06:46:36]

By contrast, this is a very helpful comment!

+class WebCryptoAlgorithm {
+public:
+#if WEBKIT_IMPLEMENTATION
+    WebCryptoAlgorithm() { }
+    WebCryptoAlgorithm(WebCryptoAlgorithmId, const char*, PassOwnPtr<WebCryptoAlgorithmParams>);
+#endif
+
+    WEBKIT_EXPORT ~WebCryptoAlgorithm();

[abarth-chromium, 2013/07/02 06:46:36]

We generally don't export destructors.  Instead, we make the destructors inline
and call a reset() method that's exported.  You can see the pattern in other API
classes.

[eroman, 2013/07/02 08:12:27]

Done.

+
+    WEBKIT_EXPORT WebCryptoAlgorithm(const WebCryptoAlgorithm&);
+    WEBKIT_EXPORT WebCryptoAlgorithm& operator=(const WebCryptoAlgorithm&);

[abarth-chromium, 2013/07/02 06:46:36]

Similarly, we don't export constructors or operators.  Instead, we define these
sorts of functions inline and call an exported assign function.  There should be
many examples of this pattern in the API.

[eroman, 2013/07/02 08:12:27]

Done.

+
+    // Returns a unique identifier for the algorithm.

[abarth-chromium, 2013/07/02 06:46:36]

Unique in what sense?  They're just identifiers for the algorithms.  I don't
think there's anything particularly unique about them.

[eroman, 2013/07/02 08:12:27]

Removed comment.

+    WEBKIT_EXPORT WebCryptoAlgorithmId algorithmId() const;
+    WEBKIT_EXPORT const char* algorithmName() const;
+
+    // Returns the specific type of parameters.
+    WEBKIT_EXPORT WebCryptoAlgorithmParamsType paramsType() const;
+
+    // Retrieves the type-specific parameters. The algorithm contains at most 1
+    // type of parameters. Retrieving an invalid parameter will return 0.
+    WebCryptoAesCbcParams* getAesCbcParams() const;

[abarth-chromium, 2013/07/02 06:46:36]

getAesCbcParams -> aesCbcParams

[eroman, 2013/07/02 08:12:27]

Done.

+    WebCryptoAesKeyGenParams* getAesKeyGenParams() const;

[abarth-chromium, 2013/07/02 06:46:36]

getAesKeyGenParams  ->  aesKeyGenParams

[eroman, 2013/07/02 08:12:27]

Done.

+
+private:
+    WebPrivatePtr<WebCryptoAlgorithmPrivate> m_private;
+};
+
+} // namespace WebKit
+
+#endif