Package net.neoforged.neoforge.coremods

Class ReplaceFieldComparisonWithInstanceOf

java.lang.Object

net.neoforged.neoforge.coremods.ReplaceFieldComparisonWithInstanceOf

All Implemented Interfaces:

ITransformer<org.objectweb.asm.tree.MethodNode>

public class ReplaceFieldComparisonWithInstanceOf
extends Object
implements ITransformer<org.objectweb.asm.tree.MethodNode>

Replaces code such as itemstack.getItem() == Items.CROSSBOW with instanceof checks such as itemstack.getItem() instanceof CrossbowItem. This transformer targets a set of methods to replace the occurrence of a single field-comparison.

Nested Class Summary

Nested classes/interfaces inherited from interface cpw.mods.modlauncher.api.ITransformer

ITransformer.Target<T>

Field Summary

Fields

Modifier and Type	Field	Description
private final String	fieldName
private final String	fieldOwner
private static final org.slf4j.Logger	LOG
private final String	replacementClassName
private final Set<ITransformer.Target<org.objectweb.asm.tree.MethodNode>>	targets

Fields inherited from interface cpw.mods.modlauncher.api.ITransformer

DEFAULT_LABEL

Constructor Summary

Constructors

Constructor	Description
ReplaceFieldComparisonWithInstanceOf(String fieldOwner, String fieldName, String replacementClassName, List<ITransformer.Target<org.objectweb.asm.tree.MethodNode>> methodsToScan)

Method Summary

Modifier and Type	Method	Description
TransformerVoteResult	castVote(ITransformerVotingContext context)	Return the TransformerVoteResult for this transformer.
TargetType<org.objectweb.asm.tree.MethodNode>	getTargetType()
Set<ITransformer.Target<org.objectweb.asm.tree.MethodNode>>	targets()	Return a set of ITransformer.Target identifying which elements this transformer wishes to try and apply to.
org.objectweb.asm.tree.MethodNode	transform(org.objectweb.asm.tree.MethodNode methodNode, ITransformerVotingContext votingContext)	Transform the input to the ITransformer's desire.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface cpw.mods.modlauncher.api.ITransformer

labels

Field Details

LOG

private static final org.slf4j.Logger LOG

targets

private final Set<ITransformer.Target<org.objectweb.asm.tree.MethodNode>> targets

fieldOwner

private final String fieldOwner

fieldName

private final String fieldName

replacementClassName

private final String replacementClassName

Constructor Details

ReplaceFieldComparisonWithInstanceOf

public ReplaceFieldComparisonWithInstanceOf(String fieldOwner,
 String fieldName,
 String replacementClassName,
 List<ITransformer.Target<org.objectweb.asm.tree.MethodNode>> methodsToScan)

Parameters:

fieldOwner - The class that owns fieldName

fieldName - The name of a field in fieldOwner

replacementClassName - Reference comparisons against fieldName in fieldOwner are replaced by instanceof checks against this class.

methodsToScan - The methods to scan

Method Details

getTargetType

public TargetType<org.objectweb.asm.tree.MethodNode> getTargetType()

Specified by:

getTargetType in interface ITransformer<org.objectweb.asm.tree.MethodNode>

targets

public Set<ITransformer.Target<org.objectweb.asm.tree.MethodNode>> targets()

Description copied from interface: ITransformer

Return a set of ITransformer.Target identifying which elements this transformer wishes to try and apply to. The ITransformer.getTargetType() must match the T variable for the transformer as documented in TargetType, other combinations will be rejected.

Specified by:

targets in interface ITransformer<org.objectweb.asm.tree.MethodNode>

Returns:

The set of targets this transformer wishes to apply to

transform

public org.objectweb.asm.tree.MethodNode transform(org.objectweb.asm.tree.MethodNode methodNode,
 ITransformerVotingContext votingContext)

Description copied from interface: ITransformer

Transform the input to the ITransformer's desire. The context from the last vote is provided as well.

Specified by:

transform in interface ITransformer<org.objectweb.asm.tree.MethodNode>

Parameters:

methodNode - The ASM input node, which can be mutated directly

votingContext - The voting context

Returns:

An ASM node of the same type as that supplied. It will be used for subsequent rounds of voting.

castVote

public TransformerVoteResult castVote(ITransformerVotingContext context)

Description copied from interface: ITransformer

Return the TransformerVoteResult for this transformer. The transformer should evaluate whether or not is is a candidate to apply during the round of voting in progress, represented by the context parameter. How the vote works:

• If the transformer wishes to be a candidate, it should return TransformerVoteResult.YES.
• If the transformer wishes to exit the voting (the transformer has already has its intended change applied, for example), it should return TransformerVoteResult.NO
• If the transformer wishes to wait for future rounds of voting it should return TransformerVoteResult.DEFER. Note that if there is no YES candidate, but DEFER candidates remain, this is a DEFERRAL stalemate and the game will crash.
• If the transformer wishes to crash the game, it should return TransformerVoteResult.REJECT. This is extremely frowned upon, and should not be used except in extreme circumstances. If an incompatibility is present, it should detect and handle it in the ITransformationService.onLoad(cpw.mods.modlauncher.api.IEnvironment, java.util.Set<java.lang.String>)

After all votes from candidate transformers are collected, the NOs are removed from the current set of voters, one from the set of YES voters is selected and it's ITransformer.transform(Object, ITransformerVotingContext) method called. It is then removed from the set of transformers and another round is performed.

Specified by:

castVote in interface ITransformer<org.objectweb.asm.tree.MethodNode>

Parameters:

context - The context of the vote

Returns:

A TransformerVoteResult indicating the desire of this transformer