chrome_paths: refactor and sanitize cache directory handling

chrome/common/chrome_paths_unittest.cc

+// Copyright (c) 2010 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 "chrome/common/chrome_paths_internal.h"
+
+#include <stdlib.h>
+
+#include "base/file_path.h"
+#include "base/file_util.h"
+#include "base/path_service.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+// Test the behavior of chrome::GetUserCacheDirectory.
+// See that function's comments for discussion of the subtleties.
+TEST(ChromePaths, UserCacheDir) {
+  FilePath test_profile_dir, cache_dir;
+#if defined(OS_MACOSX)
+  ASSERT_TRUE(PathService::Get(base::DIR_APP_DATA, &test_profile_dir));
+  test_profile_dir = test_profile_dir.Append("foobar");
+  FilePath expected_cache_dir;
+  ASSERT_TRUE(PathService::Get(base::DIR_CACHE, &expected_cache_dir));
+  expected_cache_dir = expected_cache_dir.Append("foobar");
+#elif(OS_POSIX)
+  FilePath homedir = file_util::GetHomeDir();
+  // Note: we assume XDG_CACHE_HOME/XDG_CONFIG_HOME are at their
+  // default settings.
+  test_profile_dir = homedir.Append(".config/foobar");
+  FilePath expected_cache_dir = homedir.Append(".cache/foobar");
+#endif
+
+  // Verify that a profile in the special platform-specific source
+  // location ends up in the special target location.
+#if !defined(OS_WIN)  // No special behavior on Windows.
+  chrome::GetUserCacheDirectory(test_profile_dir, &cache_dir);
+  EXPECT_EQ(expected_cache_dir.value(), cache_dir.value());
+#endif
+
+  // Verify that a profile in some other random directory doesn't use
+  // the special cache dir.
+  test_profile_dir = FilePath("/some/other/path");
+  chrome::GetUserCacheDirectory(test_profile_dir, &cache_dir);
+  EXPECT_EQ(test_profile_dir.value(), cache_dir.value());
+}