Add parsers for the Encryption and Encryption-Key HTTP headers.

components/gcm_driver/crypto/encryption_header_parsers.h

+// Copyright 2015 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.
+
+#ifndef COMPONENTS_GCM_DRIVER_CRYPTO_ENCRYPTION_HEADER_PARSERS_H_
+#define COMPONENTS_GCM_DRIVER_CRYPTO_ENCRYPTION_HEADER_PARSERS_H_
+
+#include <stdint.h>
+#include <string>
+#include <vector>
+
+namespace gcm {
+
+// Structure representing the parsed values from the Encryption HTTP header.
+// |salt| is stored after having been base64url decoded.
+struct EncryptionHeaderValues {
+  std::string keyid;
+  std::string salt;
+  uint64_t rs;
+};
+
+// Parses |input| following the syntax of the Encryption HTTP header. The parsed
+// values will be stored in the |*values| argument.
+//
+// https://tools.ietf.org/html/draft-thomson-http-encryption-01#section-3
+//
+// This header follows the #list syntax from the extended ABNF syntax
+// defined in section 1.2 of RFC 7230:
+//
+// https://tools.ietf.org/html/rfc7230#section-1.2
+//
+// Returns whether the |input| could be successfully parsed, and the resulting
+// values are now available in the |*values| argument. Does not modify |*values|
+// unless parsing was successful.
+bool ParseEncryptionHeader(const std::string& input,
+                           std::vector<EncryptionHeaderValues>* values);
+
+// Structure representing the parsed values from the Encryption-Key HTTP header.
+// |key| and |dh| are stored after having been base64url decoded.
+struct EncryptionKeyHeaderValues {
+  std::string keyid;
+  std::string key;
+  std::string dh;
+};
+
+// Parses |input| following the syntax of the Encryption-Key HTTP header. The
+// parsed values will be stored in the |*values| argument.
+//
+// https://tools.ietf.org/html/draft-thomson-http-encryption-01#section-4
+//
+// This header follows the #list syntax from the extended ABNF syntax
+// defined in section 1.2 of RFC 7230:
+//
+// https://tools.ietf.org/html/rfc7230#section-1.2
+//
+// Returns whether the |input| could be successfully parsed, and the resulting
+// values are now available in the |*values| argument. Does not modify |*values|
+// unless parsing was successful.
+bool ParseEncryptionKeyHeader(const std::string& input,
+                              std::vector<EncryptionKeyHeaderValues>* values);
+
+}  // namespace gcm
+
+#endif  // COMPONENTS_GCM_DRIVER_CRYPTO_ENCRYPTION_HEADER_PARSERS_H_