/*
 * Copyright (C) 2009-2019 The Project Lombok Authors.
 * 
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 * 
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 * 
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */
package lombok.eclipse;

import static lombok.eclipse.handlers.EclipseHandlerUtil.*;

import java.lang.reflect.Field;

import lombok.ConfigurationKeys;
import lombok.core.LombokConfiguration;
import lombok.core.debug.DebugSnapshotStore;
import lombok.core.debug.HistogramTracker;
import lombok.patcher.Symbols;
import lombok.permit.Permit;

import org.eclipse.jdt.internal.compiler.ast.AbstractMethodDeclaration;
import org.eclipse.jdt.internal.compiler.ast.Annotation;
import org.eclipse.jdt.internal.compiler.ast.Argument;
import org.eclipse.jdt.internal.compiler.ast.CompilationUnitDeclaration;
import org.eclipse.jdt.internal.compiler.ast.FieldDeclaration;
import org.eclipse.jdt.internal.compiler.ast.LocalDeclaration;
import org.eclipse.jdt.internal.compiler.ast.TypeDeclaration;
import org.eclipse.jdt.internal.compiler.ast.TypeReference;
import org.eclipse.jdt.internal.compiler.parser.Parser;

Entry point for the Eclipse Parser patch that lets lombok modify the Abstract Syntax Tree as generated by Eclipse's parser implementations. This class is injected into the appropriate OSGi ClassLoader and can thus use any classes that belong to org.eclipse.jdt.(apt.)core. Note that, for any Method body, if Bit24 is set, the Eclipse parser has been patched to never attempt to (re)parse it. You should set Bit24 on any MethodDeclaration object you inject into the AST: methodDeclaration.bits |= ASTNode.Bit24; //0x800000 
Author:
rzwitserloot, rspilker/**
 * Entry point for the Eclipse Parser patch that lets lombok modify the Abstract Syntax Tree as generated by
 * Eclipse's parser implementations. This class is injected into the appropriate OSGi ClassLoader and can thus
 * use any classes that belong to org.eclipse.jdt.(apt.)core.
 * 
 * Note that, for any Method body, if Bit24 is set, the Eclipse parser has been patched to never attempt to
 * (re)parse it. You should set Bit24 on any MethodDeclaration object you inject into the AST:
 * 
 * {@code methodDeclaration.bits |= ASTNode.Bit24; //0x800000}
 * 
 * @author rzwitserloot
 * @author rspilker
 */
public class TransformEclipseAST {
	private final EclipseAST ast;
	//The patcher hacks this field onto CUD. It's public.
	private static final Field astCacheField;
	private static final HandlerLibrary handlers;
	
	public static boolean disableLombok = false;
	private static final HistogramTracker lombokTracker;
	
	static {
		String v = System.getProperty("lombok.histogram");
		if (v == null) lombokTracker = null;
		else if (v.toLowerCase().equals("sysout")) lombokTracker = new HistogramTracker("lombok.histogram", System.out);
		else lombokTracker = new HistogramTracker("lombok.histogram");
	}
	
	static {
		Field f = null;
		HandlerLibrary h = null;
		
		if (System.getProperty("lombok.disable") != null) {
			disableLombok = true;
			astCacheField = null;
			handlers = null;
		} else {
			try {
				h = HandlerLibrary.load();
			} catch (Throwable t) {
				try {
					error(null, "Problem initializing lombok", t);
				} catch (Throwable t2) {
					System.err.println("Problem initializing lombok");
					t.printStackTrace();
				}
				disableLombok = true;
			}
			try {
				f = Permit.getField(CompilationUnitDeclaration.class, "$lombokAST");
			} catch (Throwable t) {
				//I guess we're in an ecj environment; we'll just not cache stuff then.
			}
			
			astCacheField = f;
			handlers = h;
		}
	}
	
	public static void transform_swapped(CompilationUnitDeclaration ast, Parser parser) {
		transform(parser, ast);
	}
	
	public static EclipseAST getAST(CompilationUnitDeclaration ast, boolean forceRebuild) {
		EclipseAST existing = null;
		if (astCacheField != null) {
			try {
				existing = (EclipseAST) astCacheField.get(ast);
			} catch (Exception e) {
				// existing remains null
			}
		}
		
		if (existing == null) {
			existing = new EclipseAST(ast);
			if (astCacheField != null) try {
				astCacheField.set(ast, existing);
			} catch (Exception ignore) {
			}
		} else {
			existing.rebuild(forceRebuild);
		}
		
		return existing;
	}
	
	
This method is called immediately after Eclipse finishes building a CompilationUnitDeclaration, which is
the top-level AST node when Eclipse parses a source file. The signature is 'magic' - you should not
change it!
Eclipse's parsers often operate in diet mode, which means many parts of the AST have been left blank.
Be ready to deal with just about anything being null, such as the Statement[] arrays of the Method AST nodes.
Params:
parser – The Eclipse parser object that generated the AST. Not actually used; mostly there to satisfy parameter rules for lombok.patcher scripts.
ast – The AST node belonging to the compilation unit (java speak for a single source file)./**
	 * This method is called immediately after Eclipse finishes building a CompilationUnitDeclaration, which is
	 * the top-level AST node when Eclipse parses a source file. The signature is 'magic' - you should not
	 * change it!
	 * 
	 * Eclipse's parsers often operate in diet mode, which means many parts of the AST have been left blank.
	 * Be ready to deal with just about anything being null, such as the Statement[] arrays of the Method AST nodes.
	 * 
	 * @param parser The Eclipse parser object that generated the AST. Not actually used; mostly there to satisfy parameter rules for lombok.patcher scripts.
	 * @param ast The AST node belonging to the compilation unit (java speak for a single source file).
	 */
	public static void transform(Parser parser, CompilationUnitDeclaration ast) {
		if (disableLombok) return;
		
		if (Symbols.hasSymbol("lombok.disable")) return;
		
		// Do NOT abort if (ast.bits & ASTNode.HasAllMethodBodies) != 0 - that doesn't work.
		
		if (Boolean.TRUE.equals(LombokConfiguration.read(ConfigurationKeys.LOMBOK_DISABLE, EclipseAST.getAbsoluteFileLocation(ast)))) return;
		
		try {
			DebugSnapshotStore.INSTANCE.snapshot(ast, "transform entry");
			long histoToken = lombokTracker == null ? 0L : lombokTracker.start();
			EclipseAST existing = getAST(ast, false);
			new TransformEclipseAST(existing).go();
			if (lombokTracker != null) lombokTracker.end(histoToken);
			DebugSnapshotStore.INSTANCE.snapshot(ast, "transform exit");
		} catch (Throwable t) {
			DebugSnapshotStore.INSTANCE.snapshot(ast, "transform error: %s", t.getClass().getSimpleName());
			try {
				String message = "Lombok can't parse this source: " + t.toString();
				
				EclipseAST.addProblemToCompilationResult(ast.getFileName(), ast.compilationResult, false, message, 0, 0);
				t.printStackTrace();
			} catch (Throwable t2) {
				try {
					error(ast, "Can't create an error in the problems dialog while adding: " + t.toString(), t2);
				} catch (Throwable t3) {
					//This seems risky to just silently turn off lombok, but if we get this far, something pretty
					//drastic went wrong. For example, the eclipse help system's JSP compiler will trigger a lombok call,
					//but due to class loader shenanigans we'll actually get here due to a cascade of
					//ClassNotFoundErrors. This is the right action for the help system (no lombok needed for that JSP compiler,
					//of course). 'disableLombok' is static, but each context classloader (e.g. each eclipse OSGi plugin) has
					//it's own edition of this class, so this won't turn off lombok everywhere.
					disableLombok = true;
				}
			}
		}
	}
	
	public TransformEclipseAST(EclipseAST ast) {
		this.ast = ast;
	}
	
	
First handles all lombok annotations except PrintAST, then calls all non-annotation based handlers.
then handles any PrintASTs.
/**
	 * First handles all lombok annotations except PrintAST, then calls all non-annotation based handlers.
	 * then handles any PrintASTs.
	 */
	public void go() {
		long nextPriority = Long.MIN_VALUE;
		for (Long d : handlers.getPriorities()) {
			if (nextPriority > d) continue;
			AnnotationVisitor visitor = new AnnotationVisitor(d);
			ast.traverse(visitor);
			// if no visitor interested for this AST, nextPriority would be MAX_VALUE and we bail out immediatetly
			nextPriority = visitor.getNextPriority();
			nextPriority = Math.min(nextPriority, handlers.callASTVisitors(ast, d, ast.isCompleteParse()));
		}
	}
	
	private static class AnnotationVisitor extends EclipseASTAdapter {
		private final long priority;
		// this is the next priority we continue to visit.
		// Long.MAX_VALUE means never. Each visit method will potentially reduce the next priority
		private long nextPriority = Long.MAX_VALUE;
		
		public AnnotationVisitor(long priority) {
			this.priority = priority;
		}
		
		public long getNextPriority() {
			return nextPriority;
		}
		
		@Override public void visitAnnotationOnField(FieldDeclaration field, EclipseNode annotationNode, Annotation annotation) {
			CompilationUnitDeclaration top = (CompilationUnitDeclaration) annotationNode.top().get();
			nextPriority = Math.min(nextPriority, handlers.handleAnnotation(top, annotationNode, annotation, priority));
		}
		
		@Override public void visitAnnotationOnMethodArgument(Argument arg, AbstractMethodDeclaration method, EclipseNode annotationNode, Annotation annotation) {
			CompilationUnitDeclaration top = (CompilationUnitDeclaration) annotationNode.top().get();
			nextPriority = Math.min(nextPriority, handlers.handleAnnotation(top, annotationNode, annotation, priority));
		}
		
		@Override public void visitAnnotationOnLocal(LocalDeclaration local, EclipseNode annotationNode, Annotation annotation) {
			CompilationUnitDeclaration top = (CompilationUnitDeclaration) annotationNode.top().get();
			nextPriority = Math.min(nextPriority, handlers.handleAnnotation(top, annotationNode, annotation, priority));
		}
		
		@Override public void visitAnnotationOnMethod(AbstractMethodDeclaration method, EclipseNode annotationNode, Annotation annotation) {
			CompilationUnitDeclaration top = (CompilationUnitDeclaration) annotationNode.top().get();
			nextPriority = Math.min(nextPriority, handlers.handleAnnotation(top, annotationNode, annotation, priority));
		}
		
		@Override public void visitAnnotationOnType(TypeDeclaration type, EclipseNode annotationNode, Annotation annotation) {
			CompilationUnitDeclaration top = (CompilationUnitDeclaration) annotationNode.top().get();
			nextPriority = Math.min(nextPriority, handlers.handleAnnotation(top, annotationNode, annotation, priority));
		}
		
		@Override public void visitAnnotationOnTypeUse(TypeReference typeUse, EclipseNode annotationNode, Annotation annotation) {
			CompilationUnitDeclaration top = (CompilationUnitDeclaration) annotationNode.top().get();
			nextPriority = Math.min(nextPriority, handlers.handleAnnotation(top, annotationNode, annotation, priority));
		}
	}
}