Refactor command callback definition in RemoteCommandHandler

RemoteCommandHandler was using old style function pointer to
keep commands. This patch introduces the use of function object.
The help command is now handled as any other commands thanks to
partial function definition.

Signed-off-by: Jules Clero <julesx.clero@intel.com>

Author: clero

parameter/command/include/command/Parser.h

@@ -209,7 +209,7 @@ class Parser
     //@}
 
     /** Parser items map */
-    static const CommandHandler::RemoteCommandParserItems gRemoteCommandParserItems;
+    static CommandHandler::RemoteCommandParserItems gRemoteCommandParserItems;
 
     /** Parameter Manager used to delegate parsed commands */
     CParameterMgr& mParameterMgr;

parameter/command/src/Parser.cpp

@@ -46,7 +46,7 @@ namespace core
 namespace command
 {
 
-const Parser::CommandHandler::RemoteCommandParserItems Parser::gRemoteCommandParserItems = {
+Parser::CommandHandler::RemoteCommandParserItems Parser::gRemoteCommandParserItems = {
     { "version", { &Parser::version, 0, "", "Show version" } },
     { "status", { &Parser::status, 0, "", "Show current status" } },
     { "setTuningMode",

remote-processor/RemoteCommandHandlerTemplate.h

@@ -32,6 +32,7 @@
 #include "RemoteCommandHandler.h"
 #include <vector>
 #include <map>
+#include <functional>
 
 /** Handle command of server side application
  *
@@ -56,9 +57,9 @@ class RemoteCommandHandlerTemplate : public IRemoteCommandHandler
      *
      * @return the command execution status, @see CommandStatus
      */
-    typedef CommandStatus (CommandParser::* RemoteCommandParser)(const IRemoteCommand&
-                                                                 remoteCommand,
-                                                                 std::string& strResult);
+    using RemoteCommandParser = std::function<CommandStatus(CommandParser&,
+                                                            const IRemoteCommand&,
+                                                            std::string&)>;
 
     /** Parser item definition */
     class RemoteCommandParserItem
@@ -119,7 +120,7 @@ class RemoteCommandHandlerTemplate : public IRemoteCommandHandler
                 return false;
             }
 
-            switch ((commandParser.*mParser)(remoteCommand, result)) {
+            switch (mParser(commandParser, remoteCommand, result)) {
             case EDone:
                 result = "Done";
             // Fall through intentionally
@@ -158,9 +159,22 @@ class RemoteCommandHandlerTemplate : public IRemoteCommandHandler
      * @param remoteCommandParserItems supported command parser items
      */
     RemoteCommandHandlerTemplate(CommandParser& commandParser,
-                                 const RemoteCommandParserItems& remoteCommandParserItems) :
+                                 RemoteCommandParserItems& remoteCommandParserItems) :
         _commandParser(commandParser), _remoteCommandParserItems(remoteCommandParserItems)
     {
+        /* Add the help command and specialize the help function
+         * to match RemoteCommandParser prototype
+         */
+        _remoteCommandParserItems.emplace(
+                "help",
+                RemoteCommandParserItem(
+                    std::bind(&RemoteCommandHandlerTemplate<CommandParser>::help,
+                              this,
+                              std::ref(_remoteCommandParserItems),
+                              std::placeholders::_1,
+                              std::placeholders::_2,
+                              std::placeholders::_3),
+                    0, "", "Show commands description and usage"));
     }
 
 private:
@@ -181,14 +195,6 @@ class RemoteCommandHandlerTemplate : public IRemoteCommandHandler
             return remoteCommandParserItem.parse(_commandParser, remoteCommand, result);
         }
         catch (const std::out_of_range&) {
-
-            if (remoteCommand.getCommand() == helpCommand) {
-
-                help(result);
-
-                return true;
-            }
-
             // Not found
             result = "Command not found!\nUse \"help\" to show available commands";
 
@@ -197,16 +203,25 @@ class RemoteCommandHandlerTemplate : public IRemoteCommandHandler
     }
 
     /** Format help display
+     * This method has to be able to match RemoteCommandParser prototype after partial
+     * specialization to be called like any other command. Thus, it takes a
+     * RemoteCommandParserItems in first argument and RemoteCommandParser arguments follows.
      *
+     * @param[in] items, command description container
      * @param result the formatted help string
+     *
+     * @return ESucceeded command status
      */
-    void help(std::string& result)
+    CommandStatus help(const RemoteCommandParserItems& items,
+                       CommandParser&,
+                       const IRemoteCommand&,
+                       std::string& result)
     {
         struct Help { std::string usage; std::string description; };
-        std::vector<Help> helps{ { helpCommand, helpCommandDescription } };
-        size_t maxUsage = helpCommand.length();
+        std::vector<Help> helps;
+        size_t maxUsage = 0;
 
-        for (auto& item : _remoteCommandParserItems) {
+        for (auto& item : items) {
             std::string usage = item.first + ' ' + item.second.getHelp();
             helps.push_back({ usage, item.second.getDescription() });
             maxUsage = std::max(maxUsage, usage.length());
@@ -216,24 +231,12 @@ class RemoteCommandHandlerTemplate : public IRemoteCommandHandler
             help.usage.resize(maxUsage, ' ');
             result += help.usage + " => " + help.description + '\n';
         }
+        return CommandStatus::ESucceeded;
     }
 
-    /** Help command name */
-    static const std::string helpCommand;
-
-    /** Help command description */
-    static const std::string helpCommandDescription;
-
     /** Command parser used during command during command handling */
     CommandParser& _commandParser;
 
     /** Remote command parser map */
-    const RemoteCommandParserItems& _remoteCommandParserItems;
+    RemoteCommandParserItems& _remoteCommandParserItems;
 };
-
-template <typename CommandParser>
-const std::string RemoteCommandHandlerTemplate<CommandParser>::helpCommand = "help";
-
-template <typename CommandParser>
-const std::string RemoteCommandHandlerTemplate<CommandParser>::helpCommandDescription =
-    "Show commands description and usage";

test/test-platform/command/include/command/Parser.h

@@ -171,7 +171,7 @@ class Parser
     CommandReturn getter(const IRemoteCommand& remoteCommand, std::string& strResult);
 
     /** Parser items map */
-    static const CommandHandler::RemoteCommandParserItems gRemoteCommandParserItems;
+    static CommandHandler::RemoteCommandParserItems gRemoteCommandParserItems;
 
     /** Test PLatform used to delegate parsed commands */
     CTestPlatform& mTestPlatform;

test/test-platform/command/src/Parser.cpp

@@ -41,7 +41,7 @@ namespace platform
 namespace command
 {
 
-const Parser::CommandHandler::RemoteCommandParserItems Parser::gRemoteCommandParserItems = {
+Parser::CommandHandler::RemoteCommandParserItems Parser::gRemoteCommandParserItems = {
     { "exit", { &Parser::exit, 0, "", "Exit TestPlatform" } },
     { "createExclusiveSelectionCriterionFromStateList",
       { &Parser::createCriterionFromStateList<