Allow paths up to 32767 characters on Windows (so '\\?\' can be used).

runtime/bin/directory_win.cc

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "platform/globals.h"
 #if defined(TARGET_OS_WINDOWS)
 
 #include "bin/directory.h"
 #include "bin/file.h"
 #include "bin/utils.h"
 
 #include <errno.h>  // NOLINT
 #include <sys/stat.h>  // NOLINT
 
 #include "bin/log.h"
 
 #undef DeleteFile
 
+#define MAX_LONG_PATH 32767
+
 namespace dart {
 namespace bin {
 
 PathBuffer::PathBuffer() : length_(0) {
-  data_ = calloc(MAX_PATH + 1,  sizeof(wchar_t));  // NOLINT
+  data_ = calloc(MAX_LONG_PATH + 1,  sizeof(wchar_t));  // NOLINT
 }
 
 char* PathBuffer::AsString() const {
   return StringUtils::WideToUtf8(AsStringW());
 }
 
 wchar_t* PathBuffer::AsStringW() const {
   return reinterpret_cast<wchar_t*>(data_);
 }
 
 bool PathBuffer::Add(const char* name) {
   const wchar_t* wide_name = StringUtils::Utf8ToWide(name);
   bool success = AddW(wide_name);
   free(const_cast<wchar_t*>(wide_name));
   return success;
 }
 
 bool PathBuffer::AddW(const wchar_t* name) {
   wchar_t* data = AsStringW();
   int written = _snwprintf(data + length_,
-                           MAX_PATH - length_,
+                           MAX_LONG_PATH - length_,
                            L"%s",
                            name);
-  data[MAX_PATH] = L'\0';
-  if (written <= MAX_PATH - length_ &&
+  data[MAX_LONG_PATH] = L'\0';
+  if (written <= MAX_LONG_PATH - length_ &&
       written >= 0 &&
-      static_cast<size_t>(written) == wcsnlen(name, MAX_PATH + 1)) {
+      static_cast<size_t>(written) == wcsnlen(name, MAX_LONG_PATH + 1)) {
     length_ += written;
     return true;
   } else {
     SetLastError(ERROR_BUFFER_OVERFLOW);
     return false;
   }
 }
 
 void PathBuffer::Reset(int new_length) {
   length_ = new_length;
@@ skipping 322 matching lines @@
     free(const_cast<wchar_t*>(system_name));
     return true;
   }
   free(const_cast<wchar_t*>(system_name));
   return (create_status != 0);
 }
 
 
 char* Directory::SystemTemp() {
   PathBuffer path;
-  path.Reset(GetTempPathW(MAX_PATH, path.AsStringW()) - 1);  // Remove \ at end.
+  // Remove \ at end.
+  path.Reset(GetTempPathW(MAX_LONG_PATH, path.AsStringW()) - 1);
   return path.AsString();
 }
 
 
 char* Directory::CreateTemp(const char* prefix) {
   // Returns a new, unused directory name, adding characters to the
   // end of prefix.
   // Creates this directory, with a default security
   // descriptor inherited from its parent directory.
   // The return value must be freed by the caller.
   PathBuffer path;
   const wchar_t* system_prefix = StringUtils::Utf8ToWide(prefix);
   path.AddW(system_prefix);
   free(const_cast<wchar_t*>(system_prefix));
 
   // Length of xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx is 36.
-  if (path.length() > MAX_PATH - 36) {
+  if (path.length() > MAX_LONG_PATH - 36) {
     return NULL;
   }
 
   UUID uuid;
   RPC_STATUS status = UuidCreateSequential(&uuid);
   if (status != RPC_S_OK && status != RPC_S_UUID_LOCAL_ONLY) {
     return NULL;
   }
   RPC_WSTR uuid_string;
   status = UuidToStringW(&uuid, &uuid_string);
@@ skipping 50 matching lines @@
       MoveFileExW(system_path, system_new_path, flags);
   free(const_cast<wchar_t*>(system_path));
   free(const_cast<wchar_t*>(system_new_path));
   return (move_status != 0);
 }
 
 }  // namespace bin
 }  // namespace dart
 
 #endif  // defined(TARGET_OS_WINDOWS)