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/SConstruct b/SConstruct
index 98f47a9..720c281 100644
--- a/SConstruct
+++ b/SConstruct
@@ -272,6 +272,7 @@
extent_mapper_unittest.cc
extent_ranges_unittest.cc
extent_writer_unittest.cc
+ fake_prefs.cc
fake_system_state.cc
file_writer_unittest.cc
filesystem_copier_action_unittest.cc
diff --git a/fake_prefs.cc b/fake_prefs.cc
new file mode 100644
index 0000000..1df4e30
--- /dev/null
+++ b/fake_prefs.cc
@@ -0,0 +1,123 @@
+// Copyright 2014 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.
+
+#include "update_engine/fake_prefs.h"
+
+#include <gtest/gtest.h>
+
+using std::map;
+using std::string;
+
+using chromeos_update_engine::FakePrefs;
+
+namespace {
+
+void CheckNotNull(const string& key, void* ptr) {
+ EXPECT_NE(nullptr, ptr)
+ << "Called Get*() for key \"" << key << "\" with a NULL parameter.";
+}
+
+} // namespace
+
+namespace chromeos_update_engine {
+
+// Compile-time type-dependent constants definitions.
+template<>
+FakePrefs::PrefType const FakePrefs::PrefConsts<string>::type =
+ FakePrefs::PrefType::kString;
+template<>
+string FakePrefs::PrefValue::* const FakePrefs::PrefConsts<string>::member =
+ &FakePrefs::PrefValue::as_str;
+
+template<>
+FakePrefs::PrefType const FakePrefs::PrefConsts<int64_t>::type =
+ FakePrefs::PrefType::kInt64;
+template<>
+int64_t FakePrefs::PrefValue::* const FakePrefs::PrefConsts<int64_t>::member =
+ &FakePrefs::PrefValue::as_int64;
+
+template<>
+FakePrefs::PrefType const FakePrefs::PrefConsts<bool>::type =
+ FakePrefs::PrefType::kBool;
+template<>
+bool FakePrefs::PrefValue::* const FakePrefs::PrefConsts<bool>::member =
+ &FakePrefs::PrefValue::as_bool;
+
+
+bool FakePrefs::GetString(const string& key, string* value) {
+ return GetValue(key, value);
+}
+
+bool FakePrefs::SetString(const std::string& key, const std::string& value) {
+ SetValue(key, value);
+ return true;
+}
+
+bool FakePrefs::GetInt64(const string& key, int64_t* value) {
+ return GetValue(key, value);
+}
+
+bool FakePrefs::SetInt64(const string& key, const int64_t value) {
+ SetValue(key, value);
+ return true;
+}
+
+bool FakePrefs::GetBoolean(const std::string& key, bool* value) {
+ return GetValue(key, value);
+}
+
+bool FakePrefs::SetBoolean(const string& key, const bool value) {
+ SetValue(key, value);
+ return true;
+}
+
+bool FakePrefs::Exists(const string& key) {
+ return values_.find(key) != values_.end();
+}
+
+bool FakePrefs::Delete(const string& key) {
+ if (values_.find(key) == values_.end())
+ return false;
+ values_.erase(key);
+ return true;
+}
+
+string FakePrefs::GetTypeName(PrefType type) {
+ switch (type) {
+ case PrefType::kString:
+ return "string";
+ case PrefType::kInt64:
+ return "int64_t";
+ case PrefType::kBool:
+ return "bool";
+ }
+ return "Unknown";
+}
+
+void FakePrefs::CheckKeyType(const string& key, PrefType type) const {
+ auto it = values_.find(key);
+ EXPECT_TRUE(it == values_.end() || it->second.type == type)
+ << "Key \"" << key << "\" if defined as " << GetTypeName(it->second.type)
+ << " but is accessed as a " << GetTypeName(type);
+}
+
+template<typename T>
+void FakePrefs::SetValue(const string& key, const T& value) {
+ CheckKeyType(key, PrefConsts<T>::type);
+ values_[key].type = PrefConsts<T>::type;
+ values_[key].value.*(PrefConsts<T>::member) = value;
+}
+
+template<typename T>
+bool FakePrefs::GetValue(const string& key, T* value) const {
+ CheckKeyType(key, PrefConsts<T>::type);
+ auto it = values_.find(key);
+ if (it == values_.end())
+ return false;
+ CheckNotNull(key, value);
+ *value = it->second.value.*(PrefConsts<T>::member);
+ return true;
+}
+
+} // namespace chromeos_update_engine
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_