1 files changed, 112 insertions, 0 deletions
diff --git a/security/nss/gtests/common/util.h b/security/nss/gtests/common/util.h
new file mode 100644
index 0000000000..9a4c8da106
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+++ b/security/nss/gtests/common/util.h
@@ -0,0 +1,112 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef util_h__
+#define util_h__
+
+#include <cassert>
+#include <cstdlib>
+#include <iomanip>
+#include <iostream>
+#include <sstream>
+#include <sys/stat.h>
+#include <vector>
+#if defined(_WIN32)
+#include <windows.h>
+#include <codecvt>
+#include <direct.h>
+#else
+#include <unistd.h>
+#endif
+
+#include "nspr.h"
+
+static inline std::vector<uint8_t> hex_string_to_bytes(std::string s) {
+  std::vector<uint8_t> bytes;
+  for (size_t i = 0; i < s.length(); i += 2) {
+    bytes.push_back(std::stoul(s.substr(i, 2), nullptr, 16));
+  }
+  return bytes;
+}
+
+// Given a prefix, attempts to create a unique directory that the user can do
+// work in without impacting other tests. For example, if given the prefix
+// "scratch", a directory like "scratch05c17b25" will be created in the current
+// working directory (or the location specified by NSS_GTEST_WORKDIR, if
+// defined).
+// Upon destruction, the implementation will attempt to delete the directory.
+// However, no attempt is made to first remove files in the directory - the
+// user is responsible for this. If the directory is not empty, deleting it will
+// fail.
+// Statistically, it is technically possible to fail to create a unique
+// directory name, but this is extremely unlikely given the expected workload of
+// this implementation.
+class ScopedUniqueDirectory {
+ public:
+  explicit ScopedUniqueDirectory(const std::string &prefix) {
+    std::string path;
+    const char *workingDirectory = PR_GetEnvSecure("NSS_GTEST_WORKDIR");
+    if (workingDirectory) {
+      path.assign(workingDirectory);
+    }
+    path.append(prefix);
+    for (int i = 0; i < RETRY_LIMIT; i++) {
+      std::string pathCopy(path);
+      // TryMakingDirectory will modify its input. If it fails, we want to throw
+      // away the modified result.
+      if (TryMakingDirectory(pathCopy)) {
+        mPath.assign(pathCopy);
+        break;
+      }
+    }
+    assert(mPath.length() > 0);
+#if defined(_WIN32)
+    // sqldb always uses UTF-8 regardless of the current system locale.
+    DWORD len =
+        MultiByteToWideChar(CP_ACP, 0, mPath.data(), mPath.size(), nullptr, 0);
+    std::vector<wchar_t> buf(len, L'\0');
+    MultiByteToWideChar(CP_ACP, 0, mPath.data(), mPath.size(), buf.data(),
+                        buf.size());
+    std::wstring_convert<std::codecvt_utf8_utf16<wchar_t>> converter;
+    mUTF8Path = converter.to_bytes(std::wstring(buf.begin(), buf.end()));
+#else
+    mUTF8Path = mPath;
+#endif
+  }
+
+  // NB: the directory must be empty upon destruction
+  ~ScopedUniqueDirectory() { assert(rmdir(mPath.c_str()) == 0); }
+
+  const std::string &GetPath() { return mPath; }
+  const std::string &GetUTF8Path() { return mUTF8Path; }
+
+ private:
+  static const int RETRY_LIMIT = 5;
+
+  static void GenerateRandomName(/*in/out*/ std::string &prefix) {
+    std::stringstream ss;
+    ss << prefix;
+    // RAND_MAX is at least 32767.
+    ss << std::setfill('0') << std::setw(4) << std::hex << rand() << rand();
+    // This will overwrite the value of prefix. This is a little inefficient,
+    // but at least it makes the code simple.
+    ss >> prefix;
+  }
+
+  static bool TryMakingDirectory(/*in/out*/ std::string &prefix) {
+    GenerateRandomName(prefix);
+#if defined(_WIN32)
+    return _mkdir(prefix.c_str()) == 0;
+#else
+    return mkdir(prefix.c_str(), 0777) == 0;
+#endif
+  }
+
+  std::string mPath;
+  std::string mUTF8Path;
+};
+
+#endif  // util_h__