Plugin interfaces (plugins v4)

[uniboi]

Replaces the current plugin api with source interfaces.

• backwards compatible
• no more json in binaries (wtf)
• does not rely on structs from third party libraries (wtf)
• actually initializes variables
• no more basically unused classes

The launcher exposes almost everything required by plugins in interfaces that allow for backwards compatibility.
The only thing that's passed to a plugin directly is the northstar dll HWND and a struct of data that's different for each plugin.

Plugins are required to expose a void* CreateInterface(const char* name, int* status) function to share their own interfaces.
The launcher loads the PluginId interface from the plugin to query info such as it's name.

Plugins can use the CreateInterface function exposed by the Northstar DLL to use Northstar interfaces such as for logging.
An interface is just an abstract class to force all functions into a vftable.

Northstar Interfaces

NSSys001

Exposes some system functionality to plugins

// 32 bit
enum LogLevel {
  INFO,
  WARN,
  ERR,
};

// handle: handle of the plugin. Passed to the plugin on init.
void Log(HMODULE handle, LogLevel level, char* msg); // logs a message with the plugin's log name
void Unload(HMODULE handle); // unloads the plugin
void Reload(HMODULE handle);

Required Plugin Interfaces

Interfaces that have to be exposed for the plugin to be loaded.

PluginId001

// strings of data about the plugin itself. may be extended in the future
// 32 bit
enum PluginString {
  NAME, // the name of the plugin
  LOG_NAME, // the name used for logging
  DEPENDENCY_NAME, // the name used for squirrel dependency constants created. The value returned for this has to be a valid squirrel identifier or the plugin will fail to load
}

// bitfields about the plugin
// 32 bit
enum PluginField {
  CONTEXT // 0x1 if the plugin is allowed to run on dedicated servers and 0x2 if the plugin is allowed to run on clients (is this even needed seems useless to me)
}

char* GetString(PluginString prop);
i64 GetField(PluginField prop);

PluginCallbacks001

struct PluginNorthstarData { HMODULE handle; };

// COPY THE initData IT MAY BE MOVED AT RUNTIME
void Init(HMODULE nsModule, const PluginNorthstarData* initData, bool reloaded); // called after the plugin has been validated. The nsmodule allows northstar plugins to work for the ronin client as well (assuming they update their fork lmao)
void Finalize(); // called after all plugins have been loaded. Useful for dependencies
void Unload(); // called just before the plugin is getting unloaded
void OnSqvmCreated(CSquirrelVM* sqvm); // the context of the sqvm is contained in the instance
void OnSqvmDestroying(CSquirrelVM* sqvm); // callback with the sqvm instance that's about to be destroyed (for UI, CLIENT is destroyed for some reason??)
void OnLibraryLoaded(HMODULE module, const char* libraryName); // called for any library loaded by the game (for example engine.dll)
void RunFrame(); // just runs on every frame of the game I think

What's an interface anyways?

Interfaces are just abstract classes. So make sure the first parameter is always a pointer to the instance of the interface you're using.

an example what NSSys001 looks like in C:

typedef enum {
  LOG_INFO,
  LOG_WARN,
  LOG_ERR,
};

typedef struct CSys {
  struct {
    void (*log)(struct CSys* self, HMODULE handle, LogLevel level, char* msg);
    void (*unload)(struct CSys* self, HMODULE handle);
  }* vftable;
} CSys;

// use like this
g_c_sys->vftable->log(g_c_sys, g_handle, LOG_INFO, "my balls are itching");

Interfaces are created with CreateInterface that's exposed in another dll.

Removed stuff

• plugins no longer get cvar constructs etc. Instead they are required to use the game's interfaces (the shocker)
• no squirrel api functions are exposed. Plugins need to collect the pointers themselves
• plugins are required to implement their own message buffer for the sqvm if necessary. Thank god because the one in NS sucks
• no more plugin_abi.h that you can include in plugins for the required typedefs. Not a big con because that barely worked to begin with because of the billion files the plugin_abi.h file included.

I've made an example plugin that I try to keep up to date with the new api

That's it not really that complicated imo

[catornot]

everything looks good now :)
seams to be all working well with rrplug.

although probably later there should be a pr to expose access to some hooked northstar functions.

[uniboi]

yeah interfaces aren't done and I wouldn't even consider the ones in this PR final, this is just to replace the plugin sys and expand on interfaces later

[uniboi]

what

[uniboi]

note to self; read git output before force pushing

[GeckoEidechse]

Re-confirmed working in testing. Tested with:

• loading outdated plugin (it simply gets unloaded as invalid plugin)
• Together with DiscordRPC PR: Update DiscordRPC to plugins v4 NorthstarDiscordRPC#17
  

[GeckoEidechse]

Skimmed code a bit again and overall I also like the improvement in code quality here and there (as far as I could tell).

I'm just gonna hope that other code reviews found all the potential issues and the rest we figure out post-merge ig ^^

requested have been addressed

[GeckoEidechse]

* requested changes have been addressed
(thanks for not letting me edit review dismiss GitHub, very great)