Package org.spongepowered.asm.mixin.injection.points

Class BeforeConstant

java.lang.Object

org.spongepowered.asm.mixin.injection.InjectionPoint

org.spongepowered.asm.mixin.injection.points.BeforeConstant

public class BeforeConstant
extends InjectionPoint

Special injection point which can be defined by an Constant annotation or using the at code CONSTANT.

This injection point searches for LDC and other constant opcodes matching its arguments and returns a list of injection points matching those instructions. When used with At it accepts the following parameters:

ordinal

The ordinal position of the constant opcode to match. The default value is -1 which supresses ordinal matching

named argument: nullValue

To match null literals in the method body, set this to true

named argument: intValue

To match int literals in the method body. See also the expandZeroConditions argument below for concerns when matching conditional zeroes.

named argument: floatValue

To match float literals in the method body.

named argument: longValue

To match long literals in the method body.

named argument: doubleValue

To match double literals in the method body.

named argument: stringValue

To match String literals in the method body.

named argument: classValue

To match Class literals in the method body.

named argument: log

Enable debug logging when searching for matching opcodes.

named argument: expandZeroConditions

See the Constant.expandZeroConditions() option, this argument should be a list of Constant.Condition names

Examples:

   // Find all integer constans with value 4
   @At(value = "CONSTANT", args = "intValue=4")

   // Find the String literal "foo"
   @At(value = "CONSTANT", args = "stringValue=foo"

   // Find integer constants with value 0 and expand conditionals
   @At(
     value = "CONSTANT",
     args = {
       "intValue=0",
       "expandZeroConditions=LESS_THAN_ZERO,GREATER_THAN_ZERO"
     }
   )
   

Note that like all standard injection points, this class matches the insn itself, putting the injection point immediately before the access in question. Use shift specifier to adjust the matched opcode as necessary.

Nested Class Summary

Nested classes/interfaces inherited from class org.spongepowered.asm.mixin.injection.InjectionPoint

InjectionPoint.AtCode, InjectionPoint.Flags, InjectionPoint.RestrictTargetLevel, InjectionPoint.Specifier

Field Summary

Fields inherited from class org.spongepowered.asm.mixin.injection.InjectionPoint

DEFAULT_ALLOWED_SHIFT_BY, MAX_ALLOWED_SHIFT_BY

Constructor Summary

Constructors

Constructor	Description
BeforeConstant(InjectionPointData data)
BeforeConstant(IMixinContext context, org.objectweb.asm.tree.AnnotationNode node, String returnType)

Method Summary

Modifier and Type	Method	Description
boolean	find(String desc, org.objectweb.asm.tree.InsnList insns, Collection<org.objectweb.asm.tree.AbstractInsnNode> nodes)	Find injection points in the supplied insn list
protected void	log(String message, Object... params)

Methods inherited from class org.spongepowered.asm.mixin.injection.InjectionPoint

addMessage, after, and, before, checkPriority, getAtCode, getId, getSlice, getSpecifier, getTargetRestriction, nextNode, or, parse, parse, parse, parse, parse, parse, parse, parse, register, register, setTargetRestriction, shift, toString

Methods inherited from class java.lang.Object

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

Constructor Details

BeforeConstant

public BeforeConstant(IMixinContext context,
 org.objectweb.asm.tree.AnnotationNode node,
 String returnType)

BeforeConstant

public BeforeConstant(InjectionPointData data)

Method Details

find

public boolean find(String desc,
 org.objectweb.asm.tree.InsnList insns,
 Collection<org.objectweb.asm.tree.AbstractInsnNode> nodes)

Description copied from class: InjectionPoint

Find injection points in the supplied insn list

Specified by:

find in class InjectionPoint

Parameters:

desc - Method descriptor, supplied to allow return types and arguments etc. to be determined

insns - Insn list to search in, the strategy MUST ONLY add nodes from this list to the nodes collection

nodes - Collection of nodes to populate. Injectors should NOT make any assumptions about the state of this collection and should only call the add() method

Returns:

true if one or more injection points were found

log

protected void log(String message,
 Object... params)