Refactor WebCrypto code

content/child/webcrypto/nss/sha_nss.cc

+// Copyright 2014 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.
+
+#include <sechash.h>
+#include <vector>
+
+#include "content/child/webcrypto/algorithm_implementation.h"
+#include "content/child/webcrypto/crypto_data.h"
+#include "content/child/webcrypto/nss/util_nss.h"
+#include "content/child/webcrypto/status.h"
+#include "content/child/webcrypto/webcrypto_util.h"
+#include "crypto/nss_util.h"
+#include "crypto/scoped_nss_types.h"
+
+namespace content {
+
+namespace webcrypto {
+
+namespace {
+
+HASH_HashType WebCryptoAlgorithmToNSSHashType(
+    blink::WebCryptoAlgorithmId algorithm) {
+  switch (algorithm) {
+    case blink::WebCryptoAlgorithmIdSha1:
+      return HASH_AlgSHA1;
+    case blink::WebCryptoAlgorithmIdSha256:
+      return HASH_AlgSHA256;
+    case blink::WebCryptoAlgorithmIdSha384:
+      return HASH_AlgSHA384;
+    case blink::WebCryptoAlgorithmIdSha512:
+      return HASH_AlgSHA512;
+    default:
+      // Not a digest algorithm.
+      return HASH_AlgNULL;
+  }
+}
+
+class DigestorNSS : public blink::WebCryptoDigestor {

[Ryan Sleevi, 2014/07/17 00:06:54]

document

[eroman, 2014/07/17 20:37:26]

Done: Documented as:

// Multipart input SHA digestor.

[Ryan Sleevi, 2014/07/17 22:42:55]

Doesn't really help, at least for my novel reading.

// Implementation of blink::WebCryptoDigester, an internal
// Blink detail not part of WebCrypto, that allows chunks
// of data to be streamed in before computing a SHA-1
// digest (as opposed to ShaImplementation, which computes
// digests over complete messages)

It does surprise me that it's in a directory called "webcrypto", since this
interface is not part of WebCrypto. Can leave for follow-up CL?

[eroman, 2014/07/17 23:33:23]

Done. Will followup in issue 394945.

+ public:
+  explicit DigestorNSS(blink::WebCryptoAlgorithmId algorithm_id)
+      : hash_context_(NULL), algorithm_id_(algorithm_id) {}
+
+  virtual ~DigestorNSS() {
+    if (!hash_context_)
+      return;
+
+    HASH_Destroy(hash_context_);
+    hash_context_ = NULL;
+  }
+
+  virtual bool consume(const unsigned char* data, unsigned int size) {
+    return ConsumeWithStatus(data, size).IsSuccess();
+  }
+
+  Status ConsumeWithStatus(const unsigned char* data, unsigned int size) {
+    // Initialize everything if the object hasn't been initialized yet.
+    if (!hash_context_) {
+      Status error = Init();
+      if (!error.IsSuccess())
+        return error;
+    }
+
+    HASH_Update(hash_context_, data, size);
+
+    return Status::Success();
+  }
+
+  virtual bool finish(unsigned char*& result_data,
+                      unsigned int& result_data_size) {
+    Status error = FinishInternal(result_, &result_data_size);
+    if (!error.IsSuccess())
+      return false;
+    result_data = result_;
+    return true;
+  }
+
+  Status FinishWithVectorAndStatus(std::vector<uint8>* result) {
+    if (!hash_context_)
+      return Status::ErrorUnexpected();
+
+    unsigned int result_length = HASH_ResultLenContext(hash_context_);
+    result->resize(result_length);
+    unsigned char* digest = Uint8VectorStart(result);
+    unsigned int digest_size;  // ignored
+    return FinishInternal(digest, &digest_size);
+  }
+
+ private:
+  Status Init() {
+    HASH_HashType hash_type = WebCryptoAlgorithmToNSSHashType(algorithm_id_);
+
+    if (hash_type == HASH_AlgNULL)
+      return Status::ErrorUnsupported();
+
+    hash_context_ = HASH_Create(hash_type);
+    if (!hash_context_)
+      return Status::OperationError();
+
+    HASH_Begin(hash_context_);
+
+    return Status::Success();
+  }
+
+  Status FinishInternal(unsigned char* result, unsigned int* result_size) {
+    if (!hash_context_) {
+      Status error = Init();
+      if (!error.IsSuccess())
+        return error;
+    }
+
+    unsigned int hash_result_length = HASH_ResultLenContext(hash_context_);
+    DCHECK_LE(hash_result_length, static_cast<size_t>(HASH_LENGTH_MAX));
+
+    HASH_End(hash_context_, result, result_size, hash_result_length);
+
+    if (*result_size != hash_result_length)
+      return Status::ErrorUnexpected();
+    return Status::Success();
+  }
+
+  HASHContext* hash_context_;
+  blink::WebCryptoAlgorithmId algorithm_id_;
+  unsigned char result_[HASH_LENGTH_MAX];
+};
+
+class ShaImplementation : public AlgorithmImplementation {
+ public:
+  virtual Status Digest(const blink::WebCryptoAlgorithm& algorithm,
+                        const CryptoData& data,
+                        std::vector<uint8>* buffer) const OVERRIDE {
+    DigestorNSS digestor(algorithm.id());
+    Status error = digestor.ConsumeWithStatus(data.bytes(), data.byte_length());
+    // http://crbug.com/366427: the spec does not define any other failures for
+    // digest, so none of the subsequent errors are spec compliant.
+    if (!error.IsSuccess())
+      return error;
+    return digestor.FinishWithVectorAndStatus(buffer);
+  }
+};
+
+}  // namespace
+
+AlgorithmImplementation* CreatePlatformShaImplementation() {
+  return new ShaImplementation();
+}
+
+scoped_ptr<blink::WebCryptoDigestor> CreatePlatformDigestor(
+    blink::WebCryptoAlgorithmId algorithm) {
+  return scoped_ptr<blink::WebCryptoDigestor>(new DigestorNSS(algorithm));
+}
+
+}  // namespace webcrypto
+
+}  // namespace content