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Codechange: Template DoCommand to automagically reflect the parameters of the command proc.

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When finished, this will allow each command handler to take individually
different parameters, obliviating the need for bit-packing.
This commit is contained in:
Michael Lutz
2021-10-30 01:31:46 +02:00
parent c88b104ec6
commit e740c24eb7
39 changed files with 320 additions and 229 deletions
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73
src/command_func.h
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@@ -13,6 +13,7 @@
#include "command_type.h"
#include "company_type.h"
#include <vector>
#include "tile_map.h"
/**
* Define a default return value for a failed command.
@@ -36,7 +37,6 @@ static const CommandCost CMD_ERROR = CommandCost(INVALID_STRING_ID);
/** Storage buffer for serialized command data. */
typedef std::vector<byte> CommandDataBuffer;
CommandCost DoCommand(DoCommandFlag flags, Commands cmd, TileIndex tile, uint32 p1, uint32 p2, const std::string &text = {});
bool DoCommandP(Commands cmd, StringID err_message, CommandCallback *callback, TileIndex tile, uint32 p1, uint32 p2, const std::string &text = {});
bool DoCommandP(Commands cmd, StringID err_message, TileIndex tile, uint32 p1, uint32 p2, const std::string &text = {});
@@ -58,12 +58,18 @@ const char *GetCommandName(Commands cmd);
Money GetAvailableMoneyForCommand();
bool IsCommandAllowedWhilePaused(Commands cmd);
template <Commands Tcmd>
constexpr CommandFlags GetCommandFlags()
{
return CommandTraits<Tcmd>::flags;
}
/**
* Extracts the DC flags needed for DoCommand from the flags returned by GetCommandFlags
* @param cmd_flags Flags from GetCommandFlags
* @return flags for DoCommand
*/
static inline DoCommandFlag CommandFlagsToDCFlags(CommandFlags cmd_flags)
static constexpr inline DoCommandFlag CommandFlagsToDCFlags(CommandFlags cmd_flags)
{
DoCommandFlag flags = DC_NONE;
if (cmd_flags & CMD_NO_WATER) flags |= DC_NO_WATER;
@@ -83,4 +89,67 @@ private:
static int _counter;
};
template<Commands TCmd, typename T> struct CommandHelper;
class CommandHelperBase {
protected:
static void InternalDoBefore(bool top_level, bool test);
static void InternalDoAfter(CommandCost &res, DoCommandFlag flags, bool top_level, bool test);
};
/**
* Templated wrapper that exposes the command parameter arguments
* for the various Command::Do/Post calls.
* @tparam Tcmd The command-id to execute.
* @tparam Targs The command parameter types.
*/
template <Commands Tcmd, typename... Targs>
struct CommandHelper<Tcmd, CommandCost(*)(DoCommandFlag, Targs...)> : protected CommandHelperBase {
public:
/**
* This function executes a given command with the parameters from the #CommandProc parameter list.
* Depending on the flags parameter it executes or tests a command.
*
* @note This function is to be called from the StateGameLoop or from within the execution of a Command.
* This function must not be called from the context of a "player" (real person, AI, game script).
* Use ::Post for commands directly triggered by "players".
*
* @param flags Flags for the command and how to execute the command
* @param args Parameters for the command
* @see CommandProc
* @return the cost
*/
static CommandCost Do(DoCommandFlag flags, Targs... args)
{
if constexpr (std::is_same_v<TileIndex, std::tuple_element_t<0, std::tuple<Targs...>>>) {
/* Do not even think about executing out-of-bounds tile-commands. */
TileIndex tile = std::get<0>(std::make_tuple(args...));
if (tile != 0 && (tile >= MapSize() || (!IsValidTile(tile) && (flags & DC_ALL_TILES) == 0))) return CMD_ERROR;
}
RecursiveCommandCounter counter{};
/* Only execute the test call if it's toplevel, or we're not execing. */
if (counter.IsTopLevel() || !(flags & DC_EXEC)) {
InternalDoBefore(counter.IsTopLevel(), true);
CommandCost res = CommandTraits<Tcmd>::proc(flags & ~DC_EXEC, args...);
InternalDoAfter(res, flags, counter.IsTopLevel(), true); // Can modify res.
if (res.Failed() || !(flags & DC_EXEC)) return res;
}
/* Execute the command here. All cost-relevant functions set the expenses type
* themselves to the cost object at some point. */
InternalDoBefore(counter.IsTopLevel(), false);
CommandCost res = CommandTraits<Tcmd>::proc(flags, args...);
InternalDoAfter(res, flags, counter.IsTopLevel(), false);
return res;
}
};
template <Commands Tcmd>
using Command = CommandHelper<Tcmd, typename CommandTraits<Tcmd>::ProcType>;
#endif /* COMMAND_FUNC_H */