Package com.ibm.wala.cast.js.nodejs

Class NodejsRequireTargetSelector

java.lang.Object

com.ibm.wala.cast.js.nodejs.NodejsRequireTargetSelector

All Implemented Interfaces:

MethodTargetSelector

public class NodejsRequireTargetSelector
extends Object
implements MethodTargetSelector

This class is used by WALA internals to resolve to what functions a call could potentially invoke.

Author:

Brian Pfretzschner <brian.pfretzschner@gmail.com>

Constructor Summary

Constructors

Constructor	Description
NodejsRequireTargetSelector(File rootDir, MethodTargetSelector base)

Method Summary

Modifier and Type	Method	Description
IMethod	getCalleeTarget(CGNode caller, CallSiteReference site, IClass receiver)	Basic idea: If the called method is named "__WALA__require", it is most likely the require-function mock from the module-wrapper.
static SourceFileModule	resolve(File rootDir, File dir, String target)	Implements the Nodejs require.resolve algorithm, see Node.js documentation
void	setCallGraphBuilder(PropagationCallGraphBuilder builder)

Methods inherited from class java.lang.Object

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

Constructor Details

NodejsRequireTargetSelector

public NodejsRequireTargetSelector(File rootDir,
 MethodTargetSelector base)

Method Details

setCallGraphBuilder

public void setCallGraphBuilder(PropagationCallGraphBuilder builder)

getCalleeTarget

public IMethod getCalleeTarget(CGNode caller,
 CallSiteReference site,
 IClass receiver)

Basic idea: If the called method is named "__WALA__require", it is most likely the require-function mock from the module-wrapper. To figure out what file shall be required, pointer analysis is used to identify strings that can flow into the require call. That file is than loaded, wrapped into the module wrapper and returned as method that will be invoked. Therefore, there will never be an call graph edge to the require function call, the require function is replaced by the file that is included through the require call.

Given a calling node, a call site and (optionally) a dispatch type, return the target method to be called.

Specified by:

getCalleeTarget in interface MethodTargetSelector

Parameters:

caller - the GCNode in the call graph containing the call

site - the call site reference of the call site

receiver - the type of the target object or null

Returns:

the method to be called.

resolve

public static SourceFileModule resolve(File rootDir,
 File dir,
 String target)
                                throws IOException

Implements the Nodejs require.resolve algorithm, see Node.js documentation

require(X) from module at path Y 1. If X is a core module, a. return the core module b. STOP 2. If X begins with './' or '/' or '../' a. LOAD_AS_FILE(Y + X) b. LOAD_AS_DIRECTORY(Y + X) 3. LOAD_NODE_MODULES(X, dirname(Y)) 4. THROW "not found"

Parameters:

dir - Y in the pseudo algorithm

target - X in the pseudo algorithm

Throws:

IOException