Create regulators IfAction class

Create the IfAction class that implements the "if" action in the JSON
config file.

See phosphor-regulators/docs/config_file/if.md for more information on
the "if" action.

Signed-off-by: Shawn McCarney <shawnmm@us.ibm.com>
Change-Id: I16d5ba7bb88b5baa8a5085168a8bd2dc75449e9b
diff --git a/phosphor-regulators/src/actions/if_action.cpp b/phosphor-regulators/src/actions/if_action.cpp
new file mode 100644
index 0000000..f21e7da
--- /dev/null
+++ b/phosphor-regulators/src/actions/if_action.cpp
@@ -0,0 +1,52 @@
+/**
+ * Copyright © 2019 IBM Corporation
+ *
+ * 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 "if_action.hpp"
+
+#include "action_utils.hpp"
+
+namespace phosphor::power::regulators
+{
+
+bool IfAction::execute(ActionEnvironment& environment)
+{
+    bool returnValue{true};
+
+    // Execute condition action and check whether it returned true
+    if (conditionAction->execute(environment) == true)
+    {
+        // Condition was true; execute actions in "then" clause
+        returnValue = action_utils::execute(thenActions, environment);
+    }
+    else
+    {
+        // Condition was false; check if optional "else" clause was specified
+        if (elseActions.size() > 0)
+        {
+            // Execute actions in "else" clause
+            returnValue = action_utils::execute(elseActions, environment);
+        }
+        else
+        {
+            // No "else" clause specified; return value is false in this case
+            returnValue = false;
+        }
+    }
+
+    return returnValue;
+}
+
+} // namespace phosphor::power::regulators
diff --git a/phosphor-regulators/src/actions/if_action.hpp b/phosphor-regulators/src/actions/if_action.hpp
new file mode 100644
index 0000000..13b9860
--- /dev/null
+++ b/phosphor-regulators/src/actions/if_action.hpp
@@ -0,0 +1,146 @@
+/**
+ * Copyright © 2019 IBM Corporation
+ *
+ * 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.
+ */
+#pragma once
+
+#include "action.hpp"
+#include "action_environment.hpp"
+
+#include <memory>
+#include <utility>
+#include <vector>
+
+namespace phosphor::power::regulators
+{
+
+/**
+ * @class IfAction
+ *
+ * Performs actions based on whether a condition is true.
+ *
+ * Implements the "if" action in the JSON config file.  The "if" action provides
+ * a standard if/then/else structure within the JSON config file.
+ *
+ * The "if" action contains three parts:
+ *   - condition
+ *   - then clause
+ *   - else clause (optional)
+ *
+ * The condition is a single action.  The action is executed to determine if the
+ * condition is true.
+ *
+ * If the condition is true, the actions in the "then" clause are executed.
+ *
+ * If the condition is false, the actions in the "else" clause are executed (if
+ * specified).
+ */
+class IfAction : public Action
+{
+  public:
+    // Specify which compiler-generated methods we want
+    IfAction() = delete;
+    IfAction(const IfAction&) = delete;
+    IfAction(IfAction&&) = delete;
+    IfAction& operator=(const IfAction&) = delete;
+    IfAction& operator=(IfAction&&) = delete;
+    virtual ~IfAction() = default;
+
+    /**
+     * Constructor.
+     *
+     * @param conditionAction action that tests whether condition is true
+     * @param thenActions actions to perform if condition is true
+     * @param elseActions actions to perform if condition is false (optional)
+     */
+    explicit IfAction(std::unique_ptr<Action> conditionAction,
+                      std::vector<std::unique_ptr<Action>> thenActions,
+                      std::vector<std::unique_ptr<Action>> elseActions =
+                          std::vector<std::unique_ptr<Action>>{}) :
+        conditionAction{std::move(conditionAction)},
+        thenActions{std::move(thenActions)}, elseActions{std::move(elseActions)}
+    {
+    }
+
+    /**
+     * Executes the condition action specified in the constructor.
+     *
+     * If the condition action returns true, the actions in the "then" clause
+     * will be executed.  Returns the return value of the last action in the
+     * "then" clause.
+     *
+     * If the condition action returns false, the actions in the "else" clause
+     * will be executed.  Returns the return value of the last action in the
+     * "else" clause.  If no "else" clause was specified, returns false.
+     *
+     * Throws an exception if an error occurs and an action cannot be
+     * successfully executed.
+     *
+     * @param environment action execution environment
+     * @return return value from last action in "then" or "else" clause
+     */
+    virtual bool execute(ActionEnvironment& environment) override;
+
+    /**
+     * Returns the action that tests whether the condition is true.
+     *
+     * @return condition action
+     */
+    const std::unique_ptr<Action>& getConditionAction() const
+    {
+        return conditionAction;
+    }
+
+    /**
+     * Returns the actions in the "then" clause.
+     *
+     * These actions are executed if the condition is true.
+     *
+     * @return then clause actions
+     */
+    const std::vector<std::unique_ptr<Action>>& getThenActions() const
+    {
+        return thenActions;
+    }
+
+    /**
+     * Returns the actions in the "else" clause.
+     *
+     * These actions are executed if the condition is false.
+     *
+     * @return else clause actions
+     */
+    const std::vector<std::unique_ptr<Action>>& getElseActions() const
+    {
+        return elseActions;
+    }
+
+  private:
+    /**
+     * Action that tests whether the condition is true.
+     */
+    std::unique_ptr<Action> conditionAction{};
+
+    /**
+     * Actions in the "then" clause.  Executed if condition is true.
+     */
+    std::vector<std::unique_ptr<Action>> thenActions{};
+
+    /**
+     * Actions in the "else" clause.  Executed if condition is false.  Optional.
+     */
+    std::vector<std::unique_ptr<Action>> elseActions{};
+};
+
+} // namespace phosphor::power::regulators
diff --git a/phosphor-regulators/src/meson.build b/phosphor-regulators/src/meson.build
index 76551ae..e93d65f 100644
--- a/phosphor-regulators/src/meson.build
+++ b/phosphor-regulators/src/meson.build
@@ -4,7 +4,9 @@
 )
 
 phosphor_regulators_source_files = [
-    'id_map.cpp'
+    'id_map.cpp',
+
+    'actions/if_action.cpp'
 ]
 
 phosphor_regulators_library = static_library(
diff --git a/phosphor-regulators/test/actions/if_action_tests.cpp b/phosphor-regulators/test/actions/if_action_tests.cpp
new file mode 100644
index 0000000..1f67f27
--- /dev/null
+++ b/phosphor-regulators/test/actions/if_action_tests.cpp
@@ -0,0 +1,300 @@
+/**
+ * Copyright © 2019 IBM Corporation
+ *
+ * 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 "action.hpp"
+#include "action_environment.hpp"
+#include "id_map.hpp"
+#include "if_action.hpp"
+#include "mock_action.hpp"
+
+#include <exception>
+#include <memory>
+#include <stdexcept>
+#include <utility>
+#include <vector>
+
+#include <gmock/gmock.h>
+#include <gtest/gtest.h>
+
+using namespace phosphor::power::regulators;
+
+using ::testing::Return;
+using ::testing::Throw;
+
+TEST(IfActionTests, Constructor)
+{
+    // Test where else clause is not specified
+    {
+        std::unique_ptr<Action> conditionAction =
+            std::make_unique<MockAction>();
+
+        std::vector<std::unique_ptr<Action>> thenActions{};
+        thenActions.push_back(std::make_unique<MockAction>());
+        thenActions.push_back(std::make_unique<MockAction>());
+
+        IfAction ifAction{std::move(conditionAction), std::move(thenActions)};
+        EXPECT_NE(ifAction.getConditionAction().get(), nullptr);
+        EXPECT_EQ(ifAction.getThenActions().size(), 2);
+        EXPECT_EQ(ifAction.getElseActions().size(), 0);
+    }
+
+    // Test where else clause is specified
+    {
+        std::unique_ptr<Action> conditionAction =
+            std::make_unique<MockAction>();
+
+        std::vector<std::unique_ptr<Action>> thenActions{};
+        thenActions.push_back(std::make_unique<MockAction>());
+        thenActions.push_back(std::make_unique<MockAction>());
+
+        std::vector<std::unique_ptr<Action>> elseActions{};
+        elseActions.push_back(std::make_unique<MockAction>());
+
+        IfAction ifAction{std::move(conditionAction), std::move(thenActions),
+                          std::move(elseActions)};
+        EXPECT_NE(ifAction.getConditionAction().get(), nullptr);
+        EXPECT_EQ(ifAction.getThenActions().size(), 2);
+        EXPECT_EQ(ifAction.getElseActions().size(), 1);
+    }
+}
+
+TEST(IfActionTests, Execute)
+{
+    // Create ActionEnvironment
+    IDMap idMap{};
+    ActionEnvironment env{idMap, ""};
+
+    // Test where action throws an exception
+    try
+    {
+        // Create condition action that will return true
+        std::unique_ptr<MockAction> conditionAction =
+            std::make_unique<MockAction>();
+        EXPECT_CALL(*conditionAction, execute).Times(1).WillOnce(Return(true));
+
+        // Create vector of actions for then clause
+        std::vector<std::unique_ptr<Action>> thenActions{};
+        std::unique_ptr<MockAction> thenAction;
+
+        // First then action will throw an exception
+        thenAction = std::make_unique<MockAction>();
+        EXPECT_CALL(*thenAction, execute)
+            .Times(1)
+            .WillOnce(Throw(std::logic_error{"Communication error"}));
+        thenActions.push_back(std::move(thenAction));
+
+        // Second then action should not get executed
+        thenAction = std::make_unique<MockAction>();
+        EXPECT_CALL(*thenAction, execute).Times(0);
+        thenActions.push_back(std::move(thenAction));
+
+        IfAction ifAction{std::move(conditionAction), std::move(thenActions)};
+        ifAction.execute(env);
+        ADD_FAILURE() << "Should not have reached this line.";
+    }
+    catch (const std::exception& error)
+    {
+        EXPECT_STREQ(error.what(), "Communication error");
+    }
+
+    // Test where condition is true: then clause returns true
+    try
+    {
+        // Create condition action that will return true
+        std::unique_ptr<MockAction> conditionAction =
+            std::make_unique<MockAction>();
+        EXPECT_CALL(*conditionAction, execute).Times(1).WillOnce(Return(true));
+
+        // Create vector of actions for then clause: last action returns true
+        std::vector<std::unique_ptr<Action>> thenActions{};
+        std::unique_ptr<MockAction> thenAction = std::make_unique<MockAction>();
+        EXPECT_CALL(*thenAction, execute).Times(1).WillOnce(Return(true));
+        thenActions.push_back(std::move(thenAction));
+
+        // Create vector of actions for else clause: should not be executed
+        std::vector<std::unique_ptr<Action>> elseActions{};
+        std::unique_ptr<MockAction> elseAction = std::make_unique<MockAction>();
+        EXPECT_CALL(*elseAction, execute).Times(0);
+        elseActions.push_back(std::move(elseAction));
+
+        IfAction ifAction{std::move(conditionAction), std::move(thenActions),
+                          std::move(elseActions)};
+        EXPECT_EQ(ifAction.execute(env), true);
+    }
+    catch (const std::exception& error)
+    {
+        ADD_FAILURE() << "Should not have caught exception.";
+    }
+
+    // Test where condition is true: then clause returns false
+    try
+    {
+        // Create condition action that will return true
+        std::unique_ptr<MockAction> conditionAction =
+            std::make_unique<MockAction>();
+        EXPECT_CALL(*conditionAction, execute).Times(1).WillOnce(Return(true));
+
+        // Create vector of actions for then clause: last action returns false
+        std::vector<std::unique_ptr<Action>> thenActions{};
+        std::unique_ptr<MockAction> thenAction = std::make_unique<MockAction>();
+        EXPECT_CALL(*thenAction, execute).Times(1).WillOnce(Return(false));
+        thenActions.push_back(std::move(thenAction));
+
+        // Create vector of actions for else clause: should not be executed
+        std::vector<std::unique_ptr<Action>> elseActions{};
+        std::unique_ptr<MockAction> elseAction = std::make_unique<MockAction>();
+        EXPECT_CALL(*elseAction, execute).Times(0);
+        elseActions.push_back(std::move(elseAction));
+
+        IfAction ifAction{std::move(conditionAction), std::move(thenActions),
+                          std::move(elseActions)};
+        EXPECT_EQ(ifAction.execute(env), false);
+    }
+    catch (const std::exception& error)
+    {
+        ADD_FAILURE() << "Should not have caught exception.";
+    }
+
+    // Test where condition is false: else clause returns true
+    try
+    {
+        // Create condition action that will return false
+        std::unique_ptr<MockAction> conditionAction =
+            std::make_unique<MockAction>();
+        EXPECT_CALL(*conditionAction, execute).Times(1).WillOnce(Return(false));
+
+        // Create vector of actions for then clause: should not be executed
+        std::vector<std::unique_ptr<Action>> thenActions{};
+        std::unique_ptr<MockAction> thenAction = std::make_unique<MockAction>();
+        EXPECT_CALL(*thenAction, execute).Times(0);
+        thenActions.push_back(std::move(thenAction));
+
+        // Create vector of actions for else clause: last action returns true
+        std::vector<std::unique_ptr<Action>> elseActions{};
+        std::unique_ptr<MockAction> elseAction = std::make_unique<MockAction>();
+        EXPECT_CALL(*elseAction, execute).Times(1).WillOnce(Return(true));
+        elseActions.push_back(std::move(elseAction));
+
+        IfAction ifAction{std::move(conditionAction), std::move(thenActions),
+                          std::move(elseActions)};
+        EXPECT_EQ(ifAction.execute(env), true);
+    }
+    catch (const std::exception& error)
+    {
+        ADD_FAILURE() << "Should not have caught exception.";
+    }
+
+    // Test where condition is false: else clause returns false
+    try
+    {
+        // Create condition action that will return false
+        std::unique_ptr<MockAction> conditionAction =
+            std::make_unique<MockAction>();
+        EXPECT_CALL(*conditionAction, execute).Times(1).WillOnce(Return(false));
+
+        // Create vector of actions for then clause: should not be executed
+        std::vector<std::unique_ptr<Action>> thenActions{};
+        std::unique_ptr<MockAction> thenAction = std::make_unique<MockAction>();
+        EXPECT_CALL(*thenAction, execute).Times(0);
+        thenActions.push_back(std::move(thenAction));
+
+        // Create vector of actions for else clause: last action returns false
+        std::vector<std::unique_ptr<Action>> elseActions{};
+        std::unique_ptr<MockAction> elseAction = std::make_unique<MockAction>();
+        EXPECT_CALL(*elseAction, execute).Times(1).WillOnce(Return(false));
+        elseActions.push_back(std::move(elseAction));
+
+        IfAction ifAction{std::move(conditionAction), std::move(thenActions),
+                          std::move(elseActions)};
+        EXPECT_EQ(ifAction.execute(env), false);
+    }
+    catch (const std::exception& error)
+    {
+        ADD_FAILURE() << "Should not have caught exception.";
+    }
+
+    // Test where condition is false: no else clause specified
+    try
+    {
+        // Create condition action that will return false
+        std::unique_ptr<MockAction> conditionAction =
+            std::make_unique<MockAction>();
+        EXPECT_CALL(*conditionAction, execute).Times(1).WillOnce(Return(false));
+
+        // Create vector of actions for then clause: should not be executed
+        std::vector<std::unique_ptr<Action>> thenActions{};
+        std::unique_ptr<MockAction> thenAction = std::make_unique<MockAction>();
+        EXPECT_CALL(*thenAction, execute).Times(0);
+        thenActions.push_back(std::move(thenAction));
+
+        IfAction ifAction{std::move(conditionAction), std::move(thenActions)};
+        EXPECT_EQ(ifAction.execute(env), false);
+    }
+    catch (const std::exception& error)
+    {
+        ADD_FAILURE() << "Should not have caught exception.";
+    }
+}
+
+TEST(IfActionTests, GetConditionAction)
+{
+    MockAction* conditionAction = new MockAction{};
+
+    std::vector<std::unique_ptr<Action>> thenActions{};
+
+    IfAction ifAction{std::unique_ptr<Action>{conditionAction},
+                      std::move(thenActions)};
+
+    EXPECT_EQ(ifAction.getConditionAction().get(), conditionAction);
+}
+
+TEST(IfActionTests, GetThenActions)
+{
+    std::unique_ptr<Action> conditionAction = std::make_unique<MockAction>();
+
+    std::vector<std::unique_ptr<Action>> thenActions{};
+
+    MockAction* thenAction1 = new MockAction{};
+    thenActions.push_back(std::unique_ptr<MockAction>{thenAction1});
+
+    MockAction* thenAction2 = new MockAction{};
+    thenActions.push_back(std::unique_ptr<MockAction>{thenAction2});
+
+    IfAction ifAction{std::move(conditionAction), std::move(thenActions)};
+    EXPECT_EQ(ifAction.getThenActions().size(), 2);
+    EXPECT_EQ(ifAction.getThenActions()[0].get(), thenAction1);
+    EXPECT_EQ(ifAction.getThenActions()[1].get(), thenAction2);
+}
+
+TEST(IfActionTests, GetElseActions)
+{
+    std::unique_ptr<Action> conditionAction = std::make_unique<MockAction>();
+
+    std::vector<std::unique_ptr<Action>> thenActions{};
+
+    std::vector<std::unique_ptr<Action>> elseActions{};
+
+    MockAction* elseAction1 = new MockAction{};
+    elseActions.push_back(std::unique_ptr<MockAction>{elseAction1});
+
+    MockAction* elseAction2 = new MockAction{};
+    elseActions.push_back(std::unique_ptr<MockAction>{elseAction2});
+
+    IfAction ifAction{std::move(conditionAction), std::move(thenActions),
+                      std::move(elseActions)};
+    EXPECT_EQ(ifAction.getElseActions().size(), 2);
+    EXPECT_EQ(ifAction.getElseActions()[0].get(), elseAction1);
+    EXPECT_EQ(ifAction.getElseActions()[1].get(), elseAction2);
+}
diff --git a/phosphor-regulators/test/meson.build b/phosphor-regulators/test/meson.build
index 5a9eea0..1d261f7 100644
--- a/phosphor-regulators/test/meson.build
+++ b/phosphor-regulators/test/meson.build
@@ -12,6 +12,7 @@
     'actions/action_environment_tests.cpp',
     'actions/action_utils_tests.cpp',
     'actions/and_action_tests.cpp',
+    'actions/if_action_tests.cpp',
     'actions/not_action_tests.cpp',
     'actions/or_action_tests.cpp',
     'actions/run_rule_action_tests.cpp',