Data file

A well-built Data is useless as long as it stays in memory; DataFile is what actually writes it to disk, as a JSON file tied to a simple name, and reads it back on the next launch.

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Overview

DataFile is contained in the header "remake2d/data.hpp". Each DataFile maps a given name to a single JSON file stored under SaveManager's root directory, exposed through the singleton data. It accepts both a raw Data and any type implementing ISavable directly in its save/load overloads.

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Methods

void load(Data&);
void save(const Data&);
void load(ISavable&);
void save(const ISavable&);

void        remove(void)          noexcept;     // remove file
bool        exist(void)     const noexcept;     // check if file exist
std::string path(void)      const noexcept;     // get full path
std::string name(void)      const noexcept;     // get file name

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Usage

Creating a file

No need to know the full path of a save file ahead of time; the constructor only needs a name, and the actual path resolves automatically against SaveManager's root directory:

DataFile(std::string_view name);

rmk::DataFile file("save1"); // resolves to <root>/save1.json

Saving and loading

save/load accept either a raw Data or any type implementing ISavable directly, with no distinction at the call site:

Player p;
p.name  = "Player 1";
p.score = 1500;

file.save(p);
file.load(p);

Save writes the resulting JSON to disk, overwriting any previous content, while load reads the file back and overwrites the object passed in.

Checking and removing a file

Before attempting a load on a save that might not exist yet, exist checks whether the underlying file is present on disk:

if (file.exist()) file.load(p);
else file.save(p); // first run, create it

Remove deletes the file from disk:

file.remove();

Path and name

For logging, or for displaying available saves to the player, path and name return the file's resolved location and its original name:

std::string p = file.path(); // e.g. "data/remake2d/json/save1.json"
std::string n = file.name(); // "save1"

Save location

Every DataFile resolves its path against SaveManager's root directory, exposed through the singleton data, which defaults to "data/remake2d/json/", relative to the executable:

rmk::data.root("saves"); // root = saves/

std::string root = rmk::data.root();

Changing the root only affects DataFile instances created afterwards.

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