Refactor WebCrypto code

content/child/webcrypto/openssl/sha_openssl.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 <vector>
+#include <openssl/evp.h>
+#include <openssl/sha.h>
+
+#include "base/logging.h"
+#include "content/child/webcrypto/algorithm_implementation.h"
+#include "content/child/webcrypto/crypto_data.h"
+#include "content/child/webcrypto/openssl/util_openssl.h"
+#include "content/child/webcrypto/status.h"
+#include "content/child/webcrypto/webcrypto_util.h"
+#include "crypto/openssl_util.h"
+#include "crypto/scoped_openssl_types.h"
+
+namespace content {
+
+namespace webcrypto {
+
+namespace {
+
+// 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-* digest (as opposed to ShaImplementation, which computes
+// digests over complete messages)
+class DigestorOpenSsl : public blink::WebCryptoDigestor {
+ public:
+  explicit DigestorOpenSsl(blink::WebCryptoAlgorithmId algorithm_id)
+      : initialized_(false),
+        digest_context_(EVP_MD_CTX_create()),
+        algorithm_id_(algorithm_id) {}
+
+  virtual bool consume(const unsigned char* data, unsigned int size) {
+    return ConsumeWithStatus(data, size).IsSuccess();
+  }
+
+  Status ConsumeWithStatus(const unsigned char* data, unsigned int size) {
+    crypto::OpenSSLErrStackTracer err_tracer(FROM_HERE);
+    Status error = Init();
+    if (!error.IsSuccess())
+      return error;
+
+    if (!EVP_DigestUpdate(digest_context_.get(), data, size))
+      return Status::OperationError();
+
+    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) {
+    const int hash_expected_size = EVP_MD_CTX_size(digest_context_.get());
+    result->resize(hash_expected_size);
+    unsigned char* const hash_buffer = Uint8VectorStart(result);
+    unsigned int hash_buffer_size;  // ignored
+    return FinishInternal(hash_buffer, &hash_buffer_size);
+  }
+
+ private:
+  Status Init() {
+    if (initialized_)
+      return Status::Success();
+
+    const EVP_MD* digest_algorithm = GetDigest(algorithm_id_);
+    if (!digest_algorithm)
+      return Status::ErrorUnexpected();
+
+    if (!digest_context_.get())
+      return Status::OperationError();
+
+    if (!EVP_DigestInit_ex(digest_context_.get(), digest_algorithm, NULL))
+      return Status::OperationError();
+
+    initialized_ = true;
+    return Status::Success();
+  }
+
+  Status FinishInternal(unsigned char* result, unsigned int* result_size) {
+    crypto::OpenSSLErrStackTracer err_tracer(FROM_HERE);
+    Status error = Init();
+    if (!error.IsSuccess())
+      return error;
+
+    const int hash_expected_size = EVP_MD_CTX_size(digest_context_.get());
+    if (hash_expected_size <= 0)
+      return Status::ErrorUnexpected();
+    DCHECK_LE(hash_expected_size, EVP_MAX_MD_SIZE);
+
+    if (!EVP_DigestFinal_ex(digest_context_.get(), result, result_size) ||
+        static_cast<int>(*result_size) != hash_expected_size)
+      return Status::OperationError();
+
+    return Status::Success();
+  }
+
+  bool initialized_;
+  crypto::ScopedEVP_MD_CTX digest_context_;
+  blink::WebCryptoAlgorithmId algorithm_id_;
+  unsigned char result_[EVP_MAX_MD_SIZE];
+};
+
+class ShaImplementation : public AlgorithmImplementation {
+ public:
+  virtual Status Digest(const blink::WebCryptoAlgorithm& algorithm,
+                        const CryptoData& data,
+                        std::vector<uint8>* buffer) const OVERRIDE {
+    DigestorOpenSsl 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 DigestorOpenSsl(algorithm));
+}
+
+}  // namespace webcrypto
+
+}  // namespace content