From fa0d298afafdc81d00164765903161205cf09a7e Mon Sep 17 00:00:00 2001 From: Loek Le Blansch Date: Sat, 14 Dec 2024 16:24:08 +0100 Subject: move DB fix from `loek/doxygen` to `loek/savemgr` --- src/doc/feature/savemgr.dox | 80 +++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 80 insertions(+) create mode 100644 src/doc/feature/savemgr.dox (limited to 'src/doc/feature/savemgr.dox') diff --git a/src/doc/feature/savemgr.dox b/src/doc/feature/savemgr.dox new file mode 100644 index 0000000..6aeab03 --- /dev/null +++ b/src/doc/feature/savemgr.dox @@ -0,0 +1,80 @@ +// vim:ft=doxygen +namespace crepe { +/** + +\defgroup feature_savemgr Save data +\ingroup feature +\brief Functions to persistently store and retrieve arbitrary values + +The SaveManager may be used to persistently store game state such as player +progress, statistics, achievements, etc. It works like a key-value store, where +the key is a string and the value is an arbitrary type. + +SaveManager implements the following: + +- Storage and retrieval of primitive types and strings. +- Automatic initialization of the database using default values. +- The underlying database format is journaled, which reduces the likelihood of + players losing save data when an unexpected crash occurs while the SaveManager + is writing to disk. + +\see SaveManager + +\par Example + +The SaveManager instance reference may be retrieved by calling \c +get_save_manager(). This function is available--- + +- Within (derivatives of) Script + +- \todo Within (derivatives of) Scene + +- \todo As a public member function of LoopManager + +```cpp +// Retrieve save manager +crepe::SaveManager & save_manager = get_save_manager(); +``` + +SaveManager may be used *explicitly*, using the \ref SaveManager::set "set()", +\ref SaveManager::get "get()" and \ref SaveManager::has "has()" methods: +```cpp +// Check if the key "foo" exists, and initialize it to 3 if it doesn't +if (!save_manager.has("foo")) + save_manager.set("foo", 3); +// Get value of key "foo" +int foo = save_manager.get("foo"); + +// ~~~ arbitrary game code ~~~ +foo += 10; +// ~~~ arbitrary game code ~~~ + +// Save "foo" back to database +save_manager.set("foo", foo); +``` + +Alternatively, SaveManager::get may be called with a default value as second +parameter. This changes its return type to ValueBroker, which acts as a +read/write handle to the specific key requested, and remembers the key and its +value type for you: +```cpp +// Get a read/write handle to the value stored in key "foo", and initialize it +// to 3 if it doesn't exist yet +ValueBroker foo_handle = save_manager.get("foo", 3); +int foo = foo_handle.get(); + +// ~~~ arbitrary game code ~~~ +foo += 10; +// ~~~ arbitrary game code ~~~ + +// Save back to database +foo_handle.set(foo); +``` + +To further simplify game code, the return value of SaveManager::get may be +implicitly cast to Proxy instead of ValueBroker. This allows the database value +to be used as if it were a regular variable. This usage is detailed separately +in \"\ref feature_proxy\". + +*/ +} -- cgit v1.2.3