Make USE_OPENSSL and USE_NSS mutually exclusive

base/hmac_openssl.cc

+// Copyright (c) 2010 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 "base/hmac.h"
+
+#include <openssl/hmac.h>
+
+#include <algorithm>
+#include <vector>
+
+#include "base/logging.h"
+#include "base/openssl_util.h"
+#include "base/scoped_ptr.h"
+#include "base/stl_util-inl.h"
+
+namespace base {
+
+struct HMACPlatformData {
+  std::vector<unsigned char> key;
+};
+
+HMAC::HMAC(HashAlgorithm hash_alg)
+    : hash_alg_(hash_alg), plat_(new HMACPlatformData()) {
+  // Only SHA-1 and SHA-256 hash algorithms are supported now.
+  DCHECK(hash_alg_ == SHA1 || hash_alg_ == SHA256);
+}
+
+bool HMAC::Init(const unsigned char* key, int key_length) {
+  // Init must not be called more than once on the same HMAC object.
+  DCHECK(plat_->key.empty());
+
+  plat_->key.assign(key, key + key_length);
+  return true;
+}
+
+HMAC::~HMAC() {
+  // Zero out key copy.
+  plat_->key.assign(plat_->key.size(), 0);
+  STLClearObject(&plat_->key);
+}
+
+bool HMAC::Sign(const std::string& data,
+                unsigned char* digest,
+                int digest_length) {
+  DCHECK_GE(digest_length, 0);
+  DCHECK(!plat_->key.empty());  // Init must be called before Sign.
+
+  ScopedOpenSSLSafeSizeBuffer<EVP_MAX_MD_SIZE> result(digest, digest_length);
+  return ::HMAC(hash_alg_ == SHA1 ? EVP_sha1() : EVP_sha256(),
+                &plat_->key[0], plat_->key.size(),
+                reinterpret_cast<const unsigned char*>(data.data()),
+                data.size(),
+                result.safe_buffer(), NULL);
+}
+
+}  // namespace base