edu.umd.cs.findbugs.detect

Class StreamResourceTracker

java.lang.Object

edu.umd.cs.findbugs.detect.StreamResourceTracker

All Implemented Interfaces:

ResourceTracker<Stream>

public class StreamResourceTracker
extends java.lang.Object
implements ResourceTracker<Stream>

Resource tracker which determines where streams are created, and how they are used within the method.

Author:

David Hovemeyer

Constructor Summary

Constructors

Constructor and Description
StreamResourceTracker(StreamFactory[] streamFactoryList, RepositoryLookupFailureCallback lookupFailureCallback) Constructor.

Method Summary

Methods

Modifier and Type	Method and Description
void	addStreamEscape(Stream source, Location target) Indicate that a stream escapes at the given target Location.
void	addStreamOpenLocation(Location streamOpenLocation, Stream stream) Indicate that a stream is constructed at this Location.
ResourceValueFrameModelingVisitor	createVisitor(Stream resource, org.apache.bcel.generic.ConstantPoolGen cpg) Create a ResourceValueFrameModelingVisitor to model the effect of instructions on the state of the resource.
StreamEquivalenceClass	getStreamEquivalenceClass(Stream stream) Get the equivalence class for given stream.
boolean	ignoreExceptionEdge(Edge edge, Stream resource, org.apache.bcel.generic.ConstantPoolGen cpg) Determine whether the analysis should ignore given exception edge.
boolean	ignoreImplicitExceptions(Stream resource) Determine whether the analysis should ignore exception edges on which only implicit exceptions are propagated.
boolean	isParamInstance(Stream resource, int slot) Return if the given parameter slot contains the resource instance upon entry to the method.
boolean	isResourceClose(BasicBlock basicBlock, org.apache.bcel.generic.InstructionHandle handle, org.apache.bcel.generic.ConstantPoolGen cpg, Stream resource, ResourceValueFrame frame) Determine if the given instruction is the site where a resource is closed.
Stream	isResourceCreation(BasicBlock basicBlock, org.apache.bcel.generic.InstructionHandle handle, org.apache.bcel.generic.ConstantPoolGen cpg) Determine if the given instruction is the site where a resource is created.
boolean	isResourceOpen(BasicBlock basicBlock, org.apache.bcel.generic.InstructionHandle handle, org.apache.bcel.generic.ConstantPoolGen cpg, Stream resource, ResourceValueFrame frame)
boolean	isUninterestingStreamEscape(Stream stream) Determine if an uninteresting stream escapes at given location.
void	markTransitiveUninterestingStreamEscapes() Transitively mark all streams into which uninteresting streams (such as System.out) escape.
boolean	mightCloseResource(BasicBlock basicBlock, org.apache.bcel.generic.InstructionHandle handle, org.apache.bcel.generic.ConstantPoolGen cpg) Determine if the given instruction is the site where a resource is closed.
void	setResourceCollection(ResourceCollection<Stream> resourceCollection) Set the precomputed ResourceCollection for the method.

Methods inherited from class java.lang.Object

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

Constructor Detail

StreamResourceTracker

public StreamResourceTracker(StreamFactory[] streamFactoryList,
                     RepositoryLookupFailureCallback lookupFailureCallback)

Constructor.

Parameters:

streamFactoryList - array of StreamFactory objects which determine where streams are created

lookupFailureCallback - used when class hierarchy lookups fail

Method Detail

setResourceCollection

public void setResourceCollection(ResourceCollection<Stream> resourceCollection)

Set the precomputed ResourceCollection for the method.

addStreamEscape

public void addStreamEscape(Stream source,
                   Location target)

Indicate that a stream escapes at the given target Location.

Parameters:

source - the Stream that is escaping

target - the target Location (where the stream escapes)

markTransitiveUninterestingStreamEscapes

public void markTransitiveUninterestingStreamEscapes()

Transitively mark all streams into which uninteresting streams (such as System.out) escape. This handles the rule that wrapping an uninteresting stream makes the wrapper uninteresting as well.

isUninterestingStreamEscape

public boolean isUninterestingStreamEscape(Stream stream)

Determine if an uninteresting stream escapes at given location. markTransitiveUninterestingStreamEscapes() should be called first.

Parameters:

stream - the stream

Returns:

true if an uninteresting stream escapes at the location

addStreamOpenLocation

public void addStreamOpenLocation(Location streamOpenLocation,
                         Stream stream)

Indicate that a stream is constructed at this Location.

Parameters:

streamOpenLocation - the Location

stream - the Stream opened at this Location

getStreamEquivalenceClass

public StreamEquivalenceClass getStreamEquivalenceClass(Stream stream)

Get the equivalence class for given stream. May only be called if markTransitiveUninterestingStreamEscapes() has been called.

Parameters:

stream - the stream

Returns:

the set containing the equivalence class for the given stream

isResourceCreation

public Stream isResourceCreation(BasicBlock basicBlock,
                        org.apache.bcel.generic.InstructionHandle handle,
                        org.apache.bcel.generic.ConstantPoolGen cpg)

Description copied from interface: ResourceTracker

Determine if the given instruction is the site where a resource is created.

Specified by:

isResourceCreation in interface ResourceTracker<Stream>

Parameters:

basicBlock - basic block containing the instruction

handle - the instruction

cpg - the ConstantPoolGen for the method

Returns:

an opaque Resource object if it is a creation site, or null if it is not a creation site

isResourceOpen

public boolean isResourceOpen(BasicBlock basicBlock,
                     org.apache.bcel.generic.InstructionHandle handle,
                     org.apache.bcel.generic.ConstantPoolGen cpg,
                     Stream resource,
                     ResourceValueFrame frame)

isResourceClose

public boolean isResourceClose(BasicBlock basicBlock,
                      org.apache.bcel.generic.InstructionHandle handle,
                      org.apache.bcel.generic.ConstantPoolGen cpg,
                      Stream resource,
                      ResourceValueFrame frame)

Description copied from interface: ResourceTracker

Determine if the given instruction is the site where a resource is closed.

Specified by:

isResourceClose in interface ResourceTracker<Stream>

Parameters:

basicBlock - basic block containing the instruction

handle - the instruction

cpg - the ConstantPoolGen for the method

resource - the resource, as returned by isResourceCreation()

frame - the ResourceValueFrame representing the stack prior to executing the instruction

Returns:

true if the resource is closed here, false otherwise

mightCloseResource

public boolean mightCloseResource(BasicBlock basicBlock,
                         org.apache.bcel.generic.InstructionHandle handle,
                         org.apache.bcel.generic.ConstantPoolGen cpg)
                           throws DataflowAnalysisException

Description copied from interface: ResourceTracker

Determine if the given instruction is the site where a resource is closed.

Specified by:

mightCloseResource in interface ResourceTracker<Stream>

Parameters:

basicBlock - basic block containing the instruction

handle - the instruction

cpg - the ConstantPoolGen for the method

Returns:

true if the resource is closed here, false otherwise

Throws:

DataflowAnalysisException

createVisitor

public ResourceValueFrameModelingVisitor createVisitor(Stream resource,
                                              org.apache.bcel.generic.ConstantPoolGen cpg)

Description copied from interface: ResourceTracker

Create a ResourceValueFrameModelingVisitor to model the effect of instructions on the state of the resource.

Specified by:

createVisitor in interface ResourceTracker<Stream>

Parameters:

resource - the resource we are tracking

cpg - the ConstantPoolGen of the method

Returns:

a ResourceValueFrameModelingVisitor

ignoreImplicitExceptions

public boolean ignoreImplicitExceptions(Stream resource)

Description copied from interface: ResourceTracker

Determine whether the analysis should ignore exception edges on which only implicit exceptions are propagated. This allows different resource types to be tracked with varying precision. For example, we might want to ignore implicit exceptions for stream objects, but treat them as significant for database resources.

Specified by:

ignoreImplicitExceptions in interface ResourceTracker<Stream>

Parameters:

resource - the resource being tracked

Returns:

true if implicit exceptions are significant, false if they should be ignore

ignoreExceptionEdge

public boolean ignoreExceptionEdge(Edge edge,
                          Stream resource,
                          org.apache.bcel.generic.ConstantPoolGen cpg)

Description copied from interface: ResourceTracker

Determine whether the analysis should ignore given exception edge. This allows the analysis to customize which kinds of exceptions are significant.

Specified by:

ignoreExceptionEdge in interface ResourceTracker<Stream>

Parameters:

edge - the exception edge

resource - the resource

cpg - the ConstantPoolGen

Returns:

true if exception edge should be ignored, false if it should be considered

isParamInstance

public boolean isParamInstance(Stream resource,
                      int slot)

Description copied from interface: ResourceTracker

Return if the given parameter slot contains the resource instance upon entry to the method. This is for resources passed as parameters.

Specified by:

isParamInstance in interface ResourceTracker<Stream>

Parameters:

resource - the resource

slot - the local variable slot

Returns:

true if the slot contains the resource instance, false otherwise