WebCrypto: Add WebKit API structure for keys.

Source/modules/crypto/Key.cpp

+/*
+ * 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:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *     * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include "config.h"
+#include "modules/crypto/Key.h"
+
+#include "modules/crypto/Algorithm.h"
+
+namespace WebCore {
+
+namespace {
+
+const char* keyTypeToString(WebKit::WebCryptoKeyType type)
+{
+    switch (type) {
+    case WebKit::WebCryptoKeyTypeSecret:
+        return "secret";
+    case WebKit::WebCryptoKeyTypePublic:
+        return "public";
+    case WebKit::WebCryptoKeyTypePrivate:
+        return "private";
+    }
+    ASSERT_NOT_REACHED();
+    return 0;
+}
+
+const char* keyUsageToString(WebKit::WebCryptoKeyUsage usage)
+{
+    switch (usage) {
+    case WebKit::WebCryptoKeyUsageEncrypt:
+        return "encrypt";
+    case WebKit::WebCryptoKeyUsageDecrypt:
+        return "decrypt";
+    case WebKit::WebCryptoKeyUsageSign:
+        return "sign";
+    case WebKit::WebCryptoKeyUsageVerify:
+        return "verify";
+    case WebKit::WebCryptoKeyUsageDerive:
+        return "derive";
+    case WebKit::WebCryptoKeyUsageWrap:
+        return "wrap";
+    case WebKit::WebCryptoKeyUsageUnwrap:
+        return "unwrap";
+    case WebKit::EndOfWebCryptoKeyUsage:
+        ASSERT_NOT_REACHED();
+        return 0;
+    }
+    ASSERT_NOT_REACHED();
+    return 0;
+}
+
+} // namespace
+
+Key::Key(const WebKit::WebCryptoKey& key)
+    : m_key(key)
+{
+    ScriptWrappable::init(this);
+}
+
+String Key::type() const
+{
+    return ASCIILiteral(keyTypeToString(m_key.type()));
+}
+
+bool Key::extractable() const
+{
+    return m_key.extractable();
+}
+
+Algorithm* Key::algorithm()
+{
+    if (!m_algorithm)
+        m_algorithm = Algorithm::create(m_key.algorithm());
+    return m_algorithm.get();
+}
+
+Vector<String> Key::keyUsage() const
+{
+    Vector<String> result;
+
+    // The WebCryptoKeyUsage values are consecutive powers of 2. Test each one in order.
+    for (int i = 0; (1 << i) <= WebKit::EndOfWebCryptoKeyUsage - 1; ++i) {

[abarth-chromium, 2013/07/03 21:22:54]

Why <= and -1 ?  The normal idiom is < and no -1...

+        WebKit::WebCryptoKeyUsage usage = static_cast<WebKit::WebCryptoKeyUsage>(1 << i);
+        if (m_key.keyUsage() & usage)
+            result.append(ASCIILiteral(keyUsageToString(usage)));
+    }
+    return result;
+}
+
+// Here is an alternate implementation. It doesn't require any casting, however
+// the notable downside is that anyone adding a new value to WebCryptoKeyUsage
+// must also update this function.

[abarth-chromium, 2013/07/03 21:22:54]

I think the first version is better because it's less maintenance.  The
static_cast doesn't bother me as long as we're staying in-range for the enum.

[eroman, 2013/07/03 21:35:19]

I have uploaded a new patch which switches over to the first of the alternate
implementations. PTAL. 

(I still need to do some spot manual testing to make sure it works properly,
since this doesnt have layout tests)

+Vector<String> Key::keyUsage() const
+{
+    // Make sure we are testing against all the values. If this compile assertion
+    // breaks, you must update the ifs below.
+    const int NumEnumValues = 7;
+    COMPILE_ASSERT(WebKit::EndOfWebCryptoKeyUsage == (1<<(NumEnumValues-1)) + 1, missing_enums);
+
+    Vector<String> result;
+
+    if (m_key_.keyUsage() & WebKit::WebCryptoKeyUsageEncrypt)
+        result.append(ASCIILiteral("encrypt"));
+    if (m_key_.keyUsage() & WebKit::WebCryptoKeyUsageDecrypt)
+        result.append(ASCIILiteral("decrypt"));
+    if (m_key_.keyUsage() & WebKit::WebCryptoKeyUsageSign)
+        result.append(ASCIILiteral("sign"));
+    if (m_key_.keyUsage() & WebKit::WebCryptoKeyUsageVerify)
+        result.append(ASCIILiteral("verify"));
+    if (m_key_.keyUsage() & WebKit::WebCryptoKeyUsageDerive)
+        result.append(ASCIILiteral("derive"));
+    if (m_key_.keyUsage() & WebKit::WebCryptoKeyUsageWrap)
+        result.append(ASCIILiteral("wrap"));
+    if (m_key_.keyUsage() & WebKit::WebCryptoKeyUsageUnwrap)
+        result.append(ASCIILiteral("unwrap"));
+
+    return result;
+}
+
+} // namespace WebCore