Introducing a net::GenerateMimeMultipartBoundary helper.

net/base/mime_util.h

 // Copyright (c) 2012 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 NET_BASE_MIME_UTIL_H__
 #define NET_BASE_MIME_UTIL_H__
 
 // This file defines MIME utility functions. All of them assume the MIME type
 // to be of the format specified by rfc2045. According to it, MIME types are
 // case strongly insensitive except parameter values, which may or may not be
@@ skipping 82 matching lines @@
 //
 // A Java counterpart will be generated for this enum.
 // GENERATED_JAVA_ENUM_PACKAGE: org.chromium.net
 enum CertificateMimeType {
   CERTIFICATE_MIME_TYPE_UNKNOWN,
   CERTIFICATE_MIME_TYPE_X509_USER_CERT,
   CERTIFICATE_MIME_TYPE_X509_CA_CERT,
   CERTIFICATE_MIME_TYPE_PKCS12_ARCHIVE,
 };
 
+// Generates a random MIME multipart boundary.
+// The returned string is guaranteed to be at most 70 characters long.
+NET_EXPORT std::string GenerateMimeMultipartBoundary();
+
 // Prepares one value as part of a multi-part upload request.
 NET_EXPORT void AddMultipartValueForUpload(const std::string& value_name,
                                            const std::string& value,
                                            const std::string& mime_boundary,
                                            const std::string& content_type,
                                            std::string* post_data);
 
 // Adds the final delimiter to a multi-part upload request.
 NET_EXPORT void AddMultipartFinalDelimiterForUpload(
     const std::string& mime_boundary,
     std::string* post_data);
 
 struct MimeInfo {
   const char* const mime_type;
   const char* const extensions;  // comma separated list
 };
 
 // Finds mime type of |ext| from |mappings|.
 const char* FindMimeType(const MimeInfo* mappings,
                          size_t mappings_len,
                          const std::string& ext);
 
 }  // namespace net
 
 #endif  // NET_BASE_MIME_UTIL_H__