com.netflix.java.refactor.ast.AstScanner.kt Maven / Gradle / Ivy

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Pluggable and distributed refactoring tool for Java source code
There is a newer version: 0.6.2
package com.netflix.java.refactor.ast

import com.netflix.java.refactor.CompilationUnit
import com.netflix.java.refactor.RefactorFix
import com.sun.source.util.TreePathScanner
import com.sun.tools.javac.model.JavacElements
import com.sun.tools.javac.tree.JCTree
import com.sun.tools.javac.util.Context
import java.io.File

/**
 * A separate instance will be created for each file scan, so implementations can safely hold state
 * about a source file without having to clean it up.
 */
interface AstScanner {
    fun scan(cu: CompilationUnit): T
}

abstract class SingleCompilationUnitAstScanner :
        TreePathScanner(),
        AstScanner {

    protected lateinit var cu: JCTree.JCCompilationUnit
    protected val source: File by lazy { File(cu.sourcefile.toUri().path) }
    protected val sourceText: CharSequence by lazy { cu.sourcefile.getCharContent(true) }
    
    override fun scan(cu: CompilationUnit): T {
        val (jcCu, parser) = cu
        this.cu = jcCu
        return reduce(super.scan(jcCu, parser.context), visitEnd(parser.context))
    }

    open fun visitEnd(context: Context): T? = null

    protected fun JCTree.replace(changes: String) =
            RefactorFix(this.startPosition..this.getEndPosition(cu.endPositions), changes, source)
    
    protected fun com.sun.tools.javac.util.List.replace(changes: String) =
            RefactorFix(this.head.startPosition..this.last().getEndPosition(cu.endPositions), changes, source)
    
    protected fun replace(range: IntRange, changes: String) = RefactorFix(range, changes, source)
    
    protected fun JCTree.insertAt(changes: String): RefactorFix {
        val end = this.getEndPosition(cu.endPositions)+1
        return RefactorFix(end..end, changes, source)
    }

    protected fun insertAt(pos: Int, changes: String): RefactorFix =
        RefactorFix(pos..pos, changes, source)
    
    protected fun JCTree.insertBefore(changes: String) =
            RefactorFix(this.startPosition..this.startPosition, changes, source)

    protected fun JCTree.delete(): RefactorFix {
        var start = this.startPosition
        var end = this.getEndPosition(cu.endPositions)
        if(sourceText.length > end && sourceText[end] == '\n') {
            // delete the newline and any leading whitespace too
            end++
            
            while(start > 0 && sourceText[start-1].isWhitespace() && sourceText[start-1] != '\n') {
                start--
            }
        }
        return RefactorFix(start..end, null, source)
    }

    protected fun Context.packageContaining(clazz: String) =
            JavacElements.instance(this).getTypeElement(clazz)?.owner?.toString()
    
    protected fun JCTree.source() =
            sourceText.substring(startPosition, getEndPosition(cu.endPositions))
}

open class FixingScanner : SingleCompilationUnitAstScanner>() {
    override fun reduce(r1: List?, r2: List?): List =
        (r1 ?: emptyList()).plus(r2 ?: emptyList())
}

class CompositeScanner(vararg val scanners: AstScanner>): AstScanner> {
    override fun scan(cu: CompilationUnit) =
        scanners.fold(emptyList()) { acc, scanner -> 
            acc.plus(scanner.scan(cu))
        }
}

class IfThenScanner(val ifFixesResultFrom: AstScanner>,
                    then: Array>>): AstScanner> {
    private val compositeThenRun = CompositeScanner(*then)
    
    override fun scan(cu: CompilationUnit): List {
        val fixes = ifFixesResultFrom.scan(cu)
        return if(fixes.isNotEmpty()) fixes.plus(compositeThenRun.scan(cu)) else emptyList()
    }
}