Introducing a net::GenerateMimeMultipartBoundary helper.

chrome/browser/chromeos/policy/upload_job_impl.cc

Index: chrome/browser/chromeos/policy/upload_job_impl.cc
diff --git a/chrome/browser/chromeos/policy/upload_job_impl.cc b/chrome/browser/chromeos/policy/upload_job_impl.cc
index 22cbf4d2cf75b3b8b66dbd549c9aef8e5f03dba7..b4a10fb5c68890279c3244c43b6f94a98a2d805b 100644
--- a/chrome/browser/chromeos/policy/upload_job_impl.cc
+++ b/chrome/browser/chromeos/policy/upload_job_impl.cc
@@ -7,10 +7,10 @@
 #include <set>
 
 #include "base/logging.h"
-#include "base/rand_util.h"
 #include "base/strings/stringprintf.h"
 #include "google_apis/gaia/gaia_constants.h"
 #include "google_apis/gaia/google_service_auth_error.h"
+#include "net/base/mime_util.h"
 #include "net/http/http_status_code.h"
 #include "net/url_request/url_request_status.h"
 
@@ -18,41 +18,21 @@ namespace policy {
 
 namespace {
 
-// Defines the characters that might appear in strings generated by
-// GenerateRandomString().
-const char kAlphaNum[] =
-    "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";
-
 // Format for bearer tokens in HTTP requests to access OAuth 2.0 protected
 // resources.
 const char kAuthorizationHeaderFormat[] = "Authorization: Bearer %s";
 
-// Prefix added to a randomly generated string when choosing the MIME boundary.
-const char kMultipartBoundaryPrefix[] = "----**--";
-
-// Postfix added to a randomly generated string when choosing the MIME boundary.
-const char kMultipartBoundaryPostfix[] = "--**----";
-
 // Value the "Content-Type" field will be set to in the POST request.
 const char kUploadContentType[] = "multipart/form-data";
 
 // Number of retries when randomly generating a MIME boundary.
 const int kMimeBoundaryRetries = 3;
 
-// Length of the random string for the MIME boundary.
-const int kMimeBoundarySize = 32;
-
 // Number of upload retries.
 const int kMaxRetries = 1;
 
-// Generates a random alphanumeric string of length |length|.
-std::string GenerateRandomString(size_t length) {
-  std::string random;
-  random.reserve(length);
-  for (size_t i = 0; i < length; i++)
-    random.push_back(kAlphaNum[base::RandGenerator(sizeof(kAlphaNum) - 1)]);
-  return random;
-}
+// Max size of MIME boundary according to RFC 1341, section 7.2.1.
+const size_t kMaxMimeBoundarySize = 70;
 
 }  // namespace
 
@@ -145,18 +125,9 @@ size_t DataSegment::GetDataSize() const {
   return data_->size();
 }
 
-std::string UploadJobImpl::RandomMimeBoundaryGenerator::GenerateBoundary(
-    size_t length) const {
-  std::string boundary;
-  boundary.reserve(length);
-  DCHECK_GT(length, sizeof(kMultipartBoundaryPrefix) +
-                        sizeof(kMultipartBoundaryPostfix));
-  const size_t random_part_length = length - sizeof(kMultipartBoundaryPrefix) -
-                                    sizeof(kMultipartBoundaryPostfix);
-  boundary.append(kMultipartBoundaryPrefix);
-  boundary.append(GenerateRandomString(random_part_length));
-  boundary.append(kMultipartBoundaryPostfix);
-  return boundary;
+std::string UploadJobImpl::RandomMimeBoundaryGenerator::GenerateBoundary()
+    const {
+  return net::GenerateMimeMultipartBoundary();
 }
 
 UploadJobImpl::UploadJobImpl(
@@ -241,8 +212,8 @@ bool UploadJobImpl::SetUpMultipart() {
   int retry = 0;
   do {
     found = true;
-    mime_boundary_.reset(new std::string(
-        boundary_generator_->GenerateBoundary(kMimeBoundarySize)));
+    mime_boundary_.reset(
+        new std::string(boundary_generator_->GenerateBoundary()));
     for (const auto& data_segment : data_segments_) {
       if (data_segment->CheckIfDataContains(*mime_boundary_)) {
         found = false;
@@ -266,7 +237,7 @@ bool UploadJobImpl::SetUpMultipart() {
   for (const auto& data_segment : data_segments_) {
     for (const auto& entry : data_segment->GetHeaderEntries())
       size += entry.first.size() + entry.second.size();
-    size += kMimeBoundarySize + data_segment->GetName().size() +
+    size += kMaxMimeBoundarySize + data_segment->GetName().size() +
             data_segment->GetFilename().size() + data_segment->GetDataSize();
     // Add some extra space for all the constants and control characters.
     size += 128;