win: Add implementation of ScopedTempDir

util/test/scoped_temp_dir_win.cc

+// Copyright 2015 The Crashpad Authors. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include "util/test/scoped_temp_dir.h"
+
+#include <windows.h>
+
+#include "base/logging.h"
+#include "base/rand_util.h"
+#include "base/strings/string16.h"
+#include "base/strings/stringprintf.h"
+#include "base/strings/utf_string_conversions.h"
+#include "gtest/gtest.h"
+
+namespace crashpad {
+namespace test {
+
+// static
+base::FilePath ScopedTempDir::CreateTemporaryDirectory() {
+  wchar_t temp_path[MAX_PATH + 1];
+  DWORD path_len = GetTempPath(MAX_PATH, temp_path);
+  PCHECK(path_len != 0) << "GetTempPath";
+  base::FilePath system_temp_dir(temp_path);
+
+  for (int count = 0; count < 50; ++count) {
+    // Try create a new temporary directory with random generated name. If the
+    // one we generate exists, keep trying another path name until we reach some
+    // limit.
+    base::string16 new_dir_name = base::UTF8ToUTF16(base::StringPrintf(
+        "%d_%d", GetCurrentProcessId(), base::RandInt(0, 65536)));

[Mark Mentovai, 2015/01/09 14:13:47]

Can we put something about crashpad in the name so that it’s identifiable?

Why limit the random number to only 65536?

[scottmg, 2015/01/13 21:20:56]

Done.

+
+    base::FilePath path_to_create = system_temp_dir.Append(new_dir_name);
+    if (CreateDirectory(path_to_create.value().c_str(), NULL))
+      return path_to_create;
+  }
+
+  CHECK(false) << "Couldn't find temp dir name";
+  return base::FilePath();
+}
+
+// static
+void ScopedTempDir::RecursivelyDeleteTemporaryDirectory(
+    const base::FilePath& path) {
+  // SHFILEOPSTRUCT wants the path to be terminated with two NULLs,
+  // so we have to use wcscpy because wcscpy_s writes non-NULLs
+  // into the rest of the buffer.
+  wchar_t double_terminated_path[MAX_PATH + 1] = {0};

[Mark Mentovai, 2015/01/09 14:13:47]

Because this uses clobber-prone wcscpy, it should be defensive about a path
argument longer than MAX_PATH.

Instead, how about

  base::string16 double_terminated_path(path);
  double_terminated_path += L'\0';

?

+  wcscpy(double_terminated_path, path.value().c_str());
+
+  SHFILEOPSTRUCT file_operation = {0};
+  file_operation.wFunc = FO_DELETE;
+  file_operation.pFrom = double_terminated_path;
+  file_operation.fFlags = FOF_NOERRORUI | FOF_SILENT | FOF_NOCONFIRMATION;
+  int err = SHFileOperation(&file_operation);

[Mark Mentovai, 2015/01/09 14:13:47]

I’m kinda unimpressed by this function expanding wildcards and that kind of
thing. It does a little more than we really need or want.

[scottmg, 2015/01/13 21:20:56]

OK. Mostly was based on ::RemoveDirectory suggesting it and Chrome's base using
it. But switched to a DeleteFile/RemoveDirectory version.

+
+  // Since we're passing flags to the operation telling it to be silent,
+  // it's possible for the operation to be aborted/cancelled without err
+  // being set (although MSDN doesn't give any scenarios for how this can
+  // happen). See MSDN for SHFileOperation and SHFILEOPTSTRUCT.
+  EXPECT_FALSE(file_operation.fAnyOperationsAborted);
+
+  // Some versions of Windows return ERROR_FILE_NOT_FOUND (0x2) when deleting
+  // an empty directory and some return 0x402 when they should be returning
+  // ERROR_FILE_NOT_FOUND. MSDN says Vista and up won't return 0x402.  Windows 7
+  // can return DE_INVALIDFILES (0x7C) for nonexistent directories.
+  EXPECT_TRUE(err == 0 || err == ERROR_FILE_NOT_FOUND || err == 0x402 ||
+              err == 0x7C);
+}
+
+}  // namespace test
+}  // namespace crashpad