Truncate the download file name if it exceeds the filesystem limit.

base/sys_info_win.cc

 // 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.
 
 #include "base/sys_info.h"
 
+#include <shlwapi.h>
 #include <windows.h>
 
 #include "base/file_path.h"
 #include "base/logging.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/stringprintf.h"
 #include "base/threading/thread_restrictions.h"
 #include "base/win/windows_version.h"
 
 namespace base {
@@ skipping 41 matching lines @@
   if (!GetDiskFreeSpaceExW(path.value().c_str(), &available, &total, &free)) {
     return -1;
   }
   int64 rv = static_cast<int64>(available.QuadPart);
   if (rv < 0)
     rv = kint64max;
   return rv;
 }
 
 // static
+int SysInfo::GetMaximumPathComponentLength(const FilePath& path) {
+  base::ThreadRestrictions::AssertIOAllowed();
+  if (!path.IsAbsolute())
+    return -1;
+
+  // GetVolumeInformationW takes a root path ended with a backslash.
+  std::vector<FilePath::CharType> root(path.value().begin(),
+                                       path.value().end());
+  root.resize(root.size() + 2);  // space for trailing zero and backslash.
+  PathStripToRootW(&root[0]);
+  PathAddBackslashW(&root[0]);
+
+  DWORD max_length = 0;
+  if (!GetVolumeInformationW(&root[0], NULL, 0, NULL, &max_length, NULL, NULL,
+                             0)) {
+    return -1;
+  }
+  return static_cast<int>(max_length);
+}
+
+// static
 std::string SysInfo::OperatingSystemName() {
   return "Windows NT";
 }
 
 // static
 std::string SysInfo::OperatingSystemVersion() {
   win::OSInfo* os_info = win::OSInfo::GetInstance();
   win::OSInfo::VersionNumber version_number = os_info->version_number();
   std::string version(StringPrintf("%d.%d", version_number.major,
                                    version_number.minor));
@@ skipping 40 matching lines @@
 void SysInfo::OperatingSystemVersionNumbers(int32* major_version,
                                             int32* minor_version,
                                             int32* bugfix_version) {
   win::OSInfo* os_info = win::OSInfo::GetInstance();
   *major_version = os_info->version_number().major;
   *minor_version = os_info->version_number().minor;
   *bugfix_version = 0;
 }
 
 }  // namespace base