Class EmptyElementFilter

java.lang.Object

net.fabricmc.mappingio.adapter.ForwardingMappingVisitor

net.fabricmc.mappingio.adapter.EmptyElementFilter

All Implemented Interfaces:

MappingVisitor

public class EmptyElementFilter
extends ForwardingMappingVisitor

A mapping visitor that filters out elements which effectively don't contain any data. Elements are only forwarded if they have:

• a non-null comment,
• a non-null or non-equal destination name,
• a non-null or non-equal destination descriptor,
• or a child element to which one of these points applies.

API Note:

Extending this class is allowed, but no guarantees are made regarding the stability of its protected members.

Field Summary

Fields

Modifier and Type	Field	Description
protected int	argPosition
protected String	classComment
protected String[]	classDstNames
protected String	classSrcName
protected int	dstNsCount
protected boolean	forwardClass
protected boolean	forwardedClass
protected boolean	forwardedLocal
protected boolean	forwardedMember
protected boolean	forwardLocal
protected boolean	forwardMember
protected String	localComment
protected String[]	localDstNames
protected MappedElementKind	localKind
protected int	localLvIndex
protected String	localSrcName
protected String	memberComment
protected String[]	memberDstDescs
protected String[]	memberDstNames
protected MappedElementKind	memberKind
protected String	memberSrcDesc
protected String	memberSrcName
protected boolean	relayHeaderElements
protected boolean	relayMetadata
protected final boolean	treatSrcOnDstAsEmpty
protected int	varEndOpIdx
protected int	varLvtRowIndex
protected int	varStartOpIdx
protected boolean	visitClass
protected boolean	visitLocal
protected boolean	visitMember

Fields inherited from class ForwardingMappingVisitor

next

Constructor Summary

Constructors

Constructor	Description
EmptyElementFilter(MappingVisitor next)	Creates a new EmptyElementFilter that treats destination names and descriptors which are equal to their source counterparts as empty.
EmptyElementFilter(MappingVisitor next, boolean treatSrcOnDstAsEmpty)

Method Summary

Modifier and Type	Method	Description
protected void	forward(MappedElementKind targetKind)
protected String	getSrcName(MappedElementKind targetKind)
protected void	init()
void	reset()	Reset the visitor, including any chained visitors, to allow for another independent visit (excluding visitEnd=false).
boolean	visitClass(String srcName)	Visit a class.
void	visitComment(MappedElementKind targetKind, String comment)	Comment for the specified element (last content-visited or any parent).
boolean	visitContent()	Determine whether the mapping content (classes and anything below, metadata if not part of the header) should be visited.
void	visitDstDesc(MappedElementKind targetKind, int namespace, String desc)
void	visitDstName(MappedElementKind targetKind, int namespace, String name)	Destination name for the current element.
boolean	visitElementContent(MappedElementKind targetKind)	Determine whether the element content (comment, sub-elements) should be visited.
boolean	visitEnd()	Finish the visitation pass.
boolean	visitField(String srcName, @Nullable String srcDesc)
boolean	visitHeader()	Determine whether the header (namespaces, metadata if part of the header) should be visited.
protected boolean	visitLocal(int lvIndex, @Nullable String srcName)
protected boolean	visitMember(String srcName, @Nullable String srcDesc)
void	visitMetadata(String key, @Nullable String value)
boolean	visitMethod(String srcName, @Nullable String srcDesc)
boolean	visitMethodArg(int argPosition, int lvIndex, @Nullable String srcName)	Visit a parameter.
boolean	visitMethodVar(int lvtRowIndex, int lvIndex, int startOpIdx, int endOpIdx, @Nullable String srcName)	Visit a variable.
void	visitNamespaces(String srcNamespace, List<String> dstNamespaces)

Methods inherited from class ForwardingMappingVisitor

getFlags

Methods inherited from class Object

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

Field Details

treatSrcOnDstAsEmpty

protected final boolean treatSrcOnDstAsEmpty

relayHeaderElements

protected boolean relayHeaderElements

relayMetadata

protected boolean relayMetadata

dstNsCount

protected int dstNsCount

memberKind

protected MappedElementKind memberKind

localKind

protected MappedElementKind localKind

classSrcName

protected String classSrcName

memberSrcName

protected String memberSrcName

memberSrcDesc

protected String memberSrcDesc

localSrcName

protected String localSrcName

localLvIndex

protected int localLvIndex

argPosition

protected int argPosition

varLvtRowIndex

protected int varLvtRowIndex

varStartOpIdx

protected int varStartOpIdx

varEndOpIdx

protected int varEndOpIdx

classDstNames

protected String[] classDstNames

memberDstNames

protected String[] memberDstNames

memberDstDescs

protected String[] memberDstDescs

localDstNames

protected String[] localDstNames

classComment

protected String classComment

memberComment

protected String memberComment

localComment

protected String localComment

forwardClass

protected boolean forwardClass

forwardMember

protected boolean forwardMember

forwardLocal

protected boolean forwardLocal

forwardedClass

protected boolean forwardedClass

forwardedMember

protected boolean forwardedMember

forwardedLocal

protected boolean forwardedLocal

visitClass

protected boolean visitClass

visitMember

protected boolean visitMember

visitLocal

protected boolean visitLocal

Constructor Details

EmptyElementFilter

public EmptyElementFilter(MappingVisitor next)

Creates a new EmptyElementFilter that treats destination names and descriptors which are equal to their source counterparts as empty.

Parameters:

next - The next visitor to forward the data to.

EmptyElementFilter

public EmptyElementFilter(MappingVisitor next,
 boolean treatSrcOnDstAsEmpty)

Parameters:

next - The next visitor to forward the data to.

treatSrcOnDstAsEmpty - Whether destination names and descriptors that are equal to their source counterparts should be treated as empty.

Method Details

init

protected void init()

reset

public void reset()

Description copied from interface: MappingVisitor

Reset the visitor, including any chained visitors, to allow for another independent visit (excluding visitEnd=false).

Specified by:

reset in interface MappingVisitor

Overrides:

reset in class ForwardingMappingVisitor

visitHeader

public boolean visitHeader()
                    throws IOException

Description copied from interface: MappingVisitor

Determine whether the header (namespaces, metadata if part of the header) should be visited.

Specified by:

visitHeader in interface MappingVisitor

Overrides:

visitHeader in class ForwardingMappingVisitor

Returns:

true if the header is to be visited, false otherwise.

Throws:

IOException

visitNamespaces

public void visitNamespaces(String srcNamespace,
 List<String> dstNamespaces)
                     throws IOException

Specified by:

visitNamespaces in interface MappingVisitor

Overrides:

visitNamespaces in class ForwardingMappingVisitor

Throws:

IOException

visitMetadata

public void visitMetadata(String key,
 @Nullable
 @Nullable String value)
                   throws IOException

Specified by:

visitMetadata in interface MappingVisitor

Overrides:

visitMetadata in class ForwardingMappingVisitor

Throws:

IOException

visitContent

public boolean visitContent()
                     throws IOException

Description copied from interface: MappingVisitor

Determine whether the mapping content (classes and anything below, metadata if not part of the header) should be visited.

Specified by:

visitContent in interface MappingVisitor

Overrides:

visitContent in class ForwardingMappingVisitor

Returns:

true if content is to be visited, false otherwise.

Throws:

IOException

visitClass

public boolean visitClass(String srcName)
                   throws IOException

Description copied from interface: MappingVisitor

Visit a class.

Specified by:

visitClass in interface MappingVisitor

Overrides:

visitClass in class ForwardingMappingVisitor

Parameters:

srcName - The fully qualified source name of the class, in internal form (slashes instead of dots, dollar signs for delimiting inner classes).

Returns:

Whether the class's content should be visited too.

Throws:

IOException

visitField

public boolean visitField(String srcName,
 @Nullable
 @Nullable String srcDesc)
                   throws IOException

Specified by:

visitField in interface MappingVisitor

Overrides:

visitField in class ForwardingMappingVisitor

Throws:

IOException

visitMethod

public boolean visitMethod(String srcName,
 @Nullable
 @Nullable String srcDesc)
                    throws IOException

Specified by:

visitMethod in interface MappingVisitor

Overrides:

visitMethod in class ForwardingMappingVisitor

Throws:

IOException

visitMember

protected boolean visitMember(String srcName,
 @Nullable
 @Nullable String srcDesc)
                       throws IOException

Throws:

IOException

visitMethodArg

public boolean visitMethodArg(int argPosition,
 int lvIndex,
 @Nullable
 @Nullable String srcName)
                       throws IOException

Description copied from interface: MappingVisitor

Visit a parameter.

Specified by:

visitMethodArg in interface MappingVisitor

Overrides:

visitMethodArg in class ForwardingMappingVisitor

Parameters:

argPosition - Always starts at 0 and gets incremented by 1 for each additional parameter.

lvIndex - The parameter's local variable index in the current method, also known as slot. Starts at 0 for static methods, 1 otherwise. For each additional parameter, it gets incremented by 1, or by 2 if it's a double-wide primitive (long or double).

srcName - The optional source name of the parameter.

Returns:

Whether the arg's content should be visited too.

Throws:

IOException

visitMethodVar

public boolean visitMethodVar(int lvtRowIndex,
 int lvIndex,
 int startOpIdx,
 int endOpIdx,
 @Nullable
 @Nullable String srcName)
                       throws IOException

Description copied from interface: MappingVisitor

Visit a variable.

Specified by:

visitMethodVar in interface MappingVisitor

Overrides:

visitMethodVar in class ForwardingMappingVisitor

Parameters:

lvtRowIndex - The variable's index in the method's LVT (local variable table). It is optional, so -1 can be passed instead. This is the case since LVTs themselves are optional debug information, see JVMS 4.7.13.

lvIndex - The var's local variable index in the current method, also known as slot. For each additional variable, it gets incremented by 1, or by 2 if it's a double-wide primitive (long or double). The first variable starts at the last parameter's slot plus wideness.

startOpIdx - Required for cases when the lvIndex alone doesn't uniquely identify a local variable. This is the case when variables get re-defined later on, in which case most decompilers opt to not re-define the existing var, but instead generate a new one (with both sharing the same lvIndex).

endOpIdx - Counterpart to startOpIdx. Exclusive.

srcName - The optional source name of the variable.

Returns:

Whether the var's content should be visited too.

Throws:

IOException

visitLocal

protected boolean visitLocal(int lvIndex,
 @Nullable
 @Nullable String srcName)
                      throws IOException

Throws:

IOException

visitDstName

public void visitDstName(MappedElementKind targetKind,
 int namespace,
 String name)
                  throws IOException

Description copied from interface: MappingVisitor

Destination name for the current element.

Specified by:

visitDstName in interface MappingVisitor

Overrides:

visitDstName in class ForwardingMappingVisitor

Parameters:

namespace - Namespace index (index into the dstNamespaces list in MappingVisitor.visitNamespaces(String, List)).

name - Destination name.

Throws:

IOException

getSrcName

protected String getSrcName(MappedElementKind targetKind)

visitDstDesc

public void visitDstDesc(MappedElementKind targetKind,
 int namespace,
 String desc)
                  throws IOException

Specified by:

visitDstDesc in interface MappingVisitor

Overrides:

visitDstDesc in class ForwardingMappingVisitor

Throws:

IOException

visitElementContent

public boolean visitElementContent(MappedElementKind targetKind)
                            throws IOException

Description copied from interface: MappingVisitor

Determine whether the element content (comment, sub-elements) should be visited.

Called after visiting the target itself (e.g. visitClass for targetKind=class), its dst names and descs, but before any child elements or the comment.

This is also a notification about all available dst names having been passed on.

Specified by:

visitElementContent in interface MappingVisitor

Overrides:

visitElementContent in class ForwardingMappingVisitor

Returns:

true if the contents are to be visited, false otherwise

Throws:

IOException

visitComment

public void visitComment(MappedElementKind targetKind,
 String comment)
                  throws IOException

Description copied from interface: MappingVisitor

Comment for the specified element (last content-visited or any parent).

Specified by:

visitComment in interface MappingVisitor

Overrides:

visitComment in class ForwardingMappingVisitor

Parameters:

comment - Comment as a potentially multi-line string.

Throws:

IOException

forward

protected void forward(MappedElementKind targetKind)
                throws IOException

Throws:

IOException

visitEnd

public boolean visitEnd()
                 throws IOException

Description copied from interface: MappingVisitor

Finish the visitation pass.

Implementors may throw an exception if a second pass is requested without the NEEDS_MULTIPLE_PASSES flag having been passed beforehand, but only if that behavior is documented.

Specified by:

visitEnd in interface MappingVisitor

Overrides:

visitEnd in class ForwardingMappingVisitor

Returns:

true if the visitation pass is final, false if it should be started over.

Throws:

IOException