FakePrefs implementation.
This patch implements a PrefsInterface subclass suitable for testing
that performs some checkings on the input/output. This class is
intended to be used in testing where currently the real Prefs class
is used on a temporary directory.
BUG=chromium:356906
TEST=Included in unit test build. Not used in any test.
Change-Id: I49ba4a687d4fd8fcafd27ad6cfbb1a61b94c1dd0
Reviewed-on: https://chromium-review.googlesource.com/195240
Tested-by: Alex Deymo <deymo@chromium.org>
Reviewed-by: Alex Vakulenko <avakulenko@chromium.org>
Commit-Queue: Alex Deymo <deymo@chromium.org>
diff --git a/fake_prefs.h b/fake_prefs.h
new file mode 100644
index 0000000..30c3486
--- /dev/null
+++ b/fake_prefs.h
@@ -0,0 +1,91 @@
+// Copyright (c) 2012 The Chromium OS Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef CHROMEOS_PLATFORM_UPDATE_ENGINE_FAKE_PREFS_H_
+#define CHROMEOS_PLATFORM_UPDATE_ENGINE_FAKE_PREFS_H_
+
+#include <map>
+#include <string>
+
+#include <base/basictypes.h>
+
+#include "update_engine/prefs_interface.h"
+
+namespace chromeos_update_engine {
+
+// Implements a fake preference store by storing the value associated with
+// a key in a std::map, suitable for testing. It doesn't allow to set a value on
+// a key with a different type than the previously set type. This enforces the
+// type of a given key to be fixed. Also the class checks that the Get*()
+// methods aren't called on a key set with a different type.
+
+class FakePrefs : public PrefsInterface {
+ public:
+ FakePrefs() {}
+
+ // PrefsInterface methods.
+ bool GetString(const std::string& key, std::string* value) override;
+ bool SetString(const std::string& key, const std::string& value) override;
+ bool GetInt64(const std::string& key, int64_t* value) override;
+ bool SetInt64(const std::string& key, const int64_t value) override;
+ bool GetBoolean(const std::string& key, bool* value) override;
+ bool SetBoolean(const std::string& key, const bool value) override;
+
+ bool Exists(const std::string& key) override;
+ bool Delete(const std::string& key) override;
+
+ private:
+ enum class PrefType {
+ kString,
+ kInt64,
+ kBool,
+ };
+ struct PrefValue {
+ std::string as_str;
+ int64_t as_int64;
+ bool as_bool;
+ };
+
+ struct PrefTypeValue {
+ PrefType type;
+ PrefValue value;
+ };
+
+ // Class to store compile-time type dependant constants.
+ template<typename T>
+ class PrefConsts {
+ public:
+ // The PrefType associated with T.
+ static FakePrefs::PrefType const type;
+
+ // The data member pointer to PrefValue associated with T.
+ static T FakePrefs::PrefValue::* const member;
+ };
+
+ // Returns a string representation of the PrefType useful for logging.
+ static std::string GetTypeName(PrefType type);
+
+ // Checks that the |key| is either not present or has the given |type|.
+ void CheckKeyType(const std::string& key, PrefType type) const;
+
+ // Helper function to set a value of the passed |key|. It sets the type based
+ // on the template parameter T.
+ template<typename T>
+ void SetValue(const std::string& key, const T& value);
+
+ // Helper function to get a value from the map checking for invalid calls.
+ // The function fails the test if you attempt to read a value defined as a
+ // different type. Returns whether the get succeeded.
+ template<typename T>
+ bool GetValue(const std::string& key, T* value) const;
+
+ // Container for all the key/value pairs.
+ std::map<std::string, PrefTypeValue> values_;
+
+ DISALLOW_COPY_AND_ASSIGN(FakePrefs);
+};
+
+} // namespace chromeos_update_engine
+
+#endif // CHROMEOS_PLATFORM_UPDATE_ENGINE_FAKE_PREFS_H_