Source Generation

Source-Generation

Classes inheriting IOsuNativeObject<T> represent a native object, and higher-level methods in marked with the OsuNativeFunction attribute generate a corresponding native function (UnmanagedCallersOnly).

These methods must be be static and return an ErrorCode (see Error Handling). This allows low-level error-handling logic to be universally applied to all native functions, and writing the actual logic of the function becomes more straight-forward.

Example:

source

public partial class RulesetObject : IOsuNativeObject<Ruleset>
{
    [OsuNativeFunction]
    private static ErrorCode CreateFromId(int rulesetId, NativeRuleset* rulesetPtr)
    { ... }
}

generated

public partial class BeatmapObject
{
    [CompilerGenerated]
    [UnmanagedCallersOnly(EntryPoint = "Ruleset_CreateFromId", CallConvs = [typeof(CallConvCdecl)])]
    private static ErrorCode Ruleset_CreateFromId(int rulesetId, global::osu.Native.Structures.NativeRuleset* rulesetPtr)
    {
        ErrorHandler.SetLastMessage(null);
        try
        {
            return osu.Native.Objects.RulesetObject.CreateFromId(rulesetId, rulesetPtr);
        }
        catch (Exception ex)
        {
            return ErrorHandler.HandleException(ex);
        }
    }
}

The name of the native functions is determined by the method name and class name, trimming off an optional "Object" suffix. Example: BeatmapObject and GetTitle -> Beatmap_GetTitle

Additionally, a native Destroy function is generated for the object, allowing the caller to destroy the managed object of the handle.

ManagedObjectHandle<T>

A ManagedObjectHandle<T> represents a reference to a managed object of the type T inside osu-native, and is natively depicted by an unsigned 32-bit integer. It is used for the caller to refer to managed objects inside osu-native.

internal struct ManagedObjectHandle<T>
{
    public uint Id;
}

An id of 0 represents a "null"-handle, and represent the absence of an object (the managed equivalent would be null).