Package de.geolykt.starloader.launcher

Class ASMMixinTransformer

java.lang.Object
de.geolykt.starloader.transformers.ASMTransformer
de.geolykt.starloader.launcher.ASMMixinTransformer
All Implemented Interfaces:
Comparable<ASMTransformer>, CodeTransformer
public final class ASMMixinTransformer extends ASMTransformer implements CodeTransformer

  • Constructor Summary

    Constructors
    Constructor
    Description
    ASMMixinTransformer(SLMixinService service)
     

  • Method Summary

    Modifier and Type
    Method
    Description
    boolean
    accept(@NotNull org.objectweb.asm.tree.ClassNode source)
    Transforms the provided ClassNode to the transformer's liking.
    int
    getPriority()
    Obtains the priority of this transformer.
    boolean
    isValid()
    Called everytime ASMTransformer.accept(ClassNode) is called and returns true and is used to verify whether this transformer is still needed.
    boolean
    isValidTarget(@NotNull String internalName)
    Checks whether the given class denoted by the internal name would be a valid potential transformation target.
    boolean
    isValidTarget(@NotNull String internalName, @Nullable URI codeSourceURI)
    Obtains whether this CodeTransformer instance is interested in transforming the given class.
    boolean
    transformClass(@NotNull org.objectweb.asm.tree.ClassNode node, @Nullable URI codeSourceURI)
    Optionally transforms a class, returning true if the input node was modified, false otherwise.

    Methods inherited from class de.geolykt.starloader.transformers.ASMTransformer

    compareTo

    Methods inherited from class java.lang.Object

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

  • Constructor Details

    • ASMMixinTransformer

      public ASMMixinTransformer(SLMixinService service)

  • Method Details

    • accept

      public boolean accept(@NotNull @NotNull org.objectweb.asm.tree.ClassNode source)
      Description copied from class: ASMTransformer
      Transforms the provided ClassNode to the transformer's liking. Must return true if the class node has been modified, should it not returns false, then the transformation MAY be discarded, however it could also not be discarded. It is best to assume that both are equally possible events.
      Specified by:
      accept in class ASMTransformer
      Parameters:
      source - The node to transform
      Returns:
      True if the node has been modified.

    • isValidTarget

      public boolean isValidTarget(@NotNull @NotNull String internalName, @Nullable @Nullable URI codeSourceURI)
      Description copied from interface: CodeTransformer
      Obtains whether this CodeTransformer instance is interested in transforming the given class. Returns true if the class with the given internal name is of interest to this transformer, false otherwise.

      The caller of this method must not call CodeTransformer.transformClass(ClassNode, URI) for classes with the same name as the one used in a call to this method if that call returned false. This is a performance-saving measure and is very much akin to ASMTransformer.isValidTarget(String), except that is also exposes the codeSourceURI of the class.

      If no transformers mark a class as a valid target, then the bytecode of the class does not need to be transformed into a ClassNode, saving some CPU cycles (meaning faster startup times).

      The code source property ought not be confused with the ClassNode.sourceFile property of a class. Instead it corresponds to CodeSource.getLocation(), hinting at the location of the compiled bytecode.

      Specified by:
      isValidTarget in interface CodeTransformer
      Parameters:
      internalName - The internal name of the class, as per Type.getInternalName().
      codeSourceURI - A URI representing the location of the class source code. This URI will correspond to the JAR in which the class is located in, or the "base" directory of the class as per the classpath. This argument may be null if the caller does not know (or rather - cannot determine) the location of the class bytecode.
      Returns:
      True if the target is to be transformed, false otherwise.
      See Also:

    • isValidTarget

      public boolean isValidTarget(@NotNull @NotNull String internalName)
      Description copied from class: ASMTransformer
      Checks whether the given class denoted by the internal name would be a valid potential transformation target. If this method returns false, then ASMTransformer.accept(ClassNode) should NOT be called, however if it returns true, then it may get called. ASMTransformer.accept(ClassNode) will not always return true when this method does, however that method should never return true when this method returns false.
      Specified by:
      isValidTarget in class ASMTransformer
      Parameters:
      internalName - The internal name of the class
      Returns:
      Whether it is a potential target
      See Also:
      • Type.getInternalName()

    • isValid

      public boolean isValid()
      Description copied from class: ASMTransformer
      Called everytime ASMTransformer.accept(ClassNode) is called and returns true and is used to verify whether this transformer is still needed. Should this method returns false then the transformer is removed from the classloader's transformer pool.
      Overrides:
      isValid in class ASMTransformer
      Returns:
      Whether this transformer is still needed

    • getPriority

      public int getPriority()
      Description copied from class: ASMTransformer
      Obtains the priority of this transformer. The priority is used to note when a transformer should be applied in relation to other transformers. Should two transformers have the same priority, the order will be arbitrary.

      Transformers with a lower numeric priority value are run first. That is, the higher the priority of a transformer, the more "final" it's descision is.

      Important transform priorities are:

      Overrides:
      getPriority in class ASMTransformer
      Returns:
      The priority of the transformer

    • transformClass

      public boolean transformClass(@NotNull @NotNull org.objectweb.asm.tree.ClassNode node, @Nullable @Nullable URI codeSourceURI)
      Description copied from interface: CodeTransformer
      Optionally transforms a class, returning true if the input node was modified, false otherwise.

      If the node was transformed while this method returned false, the applied transformations may get discarded, or may also not get discarded. The exact behaviour will likely depend on the behaviour of other classes. Please be aware that debugging such edge case behaviour is extremely difficult as the cause and effects will likely seem to be completely disconnected to the average programmer, and will further not be reproducible in every environment. The return flag mainly exists for performance reasons as converting ClassNode into byte[] isn't exactly free.

      The transformation occurs in-situ, meaning that the input ClassNode is transformed as-is without any cloning. Thus the input node is also the output node in some sense.

      Specified by:
      transformClass in interface CodeTransformer
      Parameters:
      node - The input and output ClassNode to transform.
      codeSourceURI - The URI where this class is located in, following the paradigms of CodeSource.getLocation(). For classes located inside JARs, the URI of the jar will be used. For classes within directories, the URI of the directory is used (i.e. file://bin/ for file://bin/com/example/Main.class). If the location of the class file is unknown or cannot be represented as an URI, null should be used.
      Returns:
      true if the input node was transformed, false otherwise.