Copyright (c) 2000, 2018 IBM Corporation and others.
This program and the accompanying materials
are made available under the terms of the Eclipse Public License 2.0
which accompanies this distribution, and is available at
https://www.eclipse.org/legal/epl-2.0/
SPDX-License-Identifier: EPL-2.0
Contributors:
    IBM Corporation - initial API and implementation
/*******************************************************************************
 * Copyright (c) 2000, 2018 IBM Corporation and others.
 *
 * This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License 2.0
 * which accompanies this distribution, and is available at
 * https://www.eclipse.org/legal/epl-2.0/
 *
 * SPDX-License-Identifier: EPL-2.0
 *
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
package org.eclipse.jdt.internal.core.util;

import java.util.HashMap;
import java.util.HashSet;

import org.eclipse.core.resources.IFile;
import org.eclipse.core.resources.IProject;
import org.eclipse.core.resources.ResourcesPlugin;
import org.eclipse.core.runtime.CoreException;
import org.eclipse.core.runtime.IPath;
import org.eclipse.core.runtime.Path;
import org.eclipse.jdt.core.IClassFile;
import org.eclipse.jdt.core.IClasspathEntry;
import org.eclipse.jdt.core.ICompilationUnit;
import org.eclipse.jdt.core.IJavaElement;
import org.eclipse.jdt.core.IJavaProject;
import org.eclipse.jdt.core.IMember;
import org.eclipse.jdt.core.IPackageFragment;
import org.eclipse.jdt.core.IPackageFragmentRoot;
import org.eclipse.jdt.core.IType;
import org.eclipse.jdt.core.JavaCore;
import org.eclipse.jdt.core.JavaModelException;
import org.eclipse.jdt.core.compiler.CharOperation;
import org.eclipse.jdt.core.search.IJavaSearchScope;
import org.eclipse.jdt.internal.compiler.ast.*;
import org.eclipse.jdt.internal.compiler.ast.LambdaExpression;
import org.eclipse.jdt.internal.compiler.lookup.ClassScope;
import org.eclipse.jdt.internal.compiler.lookup.MethodScope;
import org.eclipse.jdt.internal.compiler.lookup.ProblemMethodBinding;
import org.eclipse.jdt.internal.compiler.lookup.Scope;
import org.eclipse.jdt.internal.compiler.lookup.TypeConstants;
import org.eclipse.jdt.internal.compiler.util.HashtableOfObjectToInt;
import org.eclipse.jdt.internal.core.*;
import org.eclipse.jdt.internal.core.search.AbstractJavaSearchScope;
import org.eclipse.jdt.internal.core.util.Util;

Creates java element handles.
/**
 * Creates java element handles.
 */
@SuppressWarnings({"rawtypes", "unchecked"})
public class HandleFactory {

	
Cache package fragment root information to optimize speed performance.
/**
	 * Cache package fragment root information to optimize speed performance.
	 */
	private String lastPkgFragmentRootPath;
	private PackageFragmentRoot lastPkgFragmentRoot;

	
Cache package handles to optimize memory.
/**
	 * Cache package handles to optimize memory.
	 */
	private HashtableOfArrayToObject packageHandles;

	private JavaModel javaModel;

	private HashtableOfObjectToInt localOccurrenceCounts = new HashtableOfObjectToInt(5);

	public HandleFactory() {
		this.javaModel = JavaModelManager.getJavaModelManager().getJavaModel();
	}


	
Creates an Openable handle from the given resource path.
The resource path can be a path to a file in the workbench (e.g. /Proj/com/ibm/jdt/core/HandleFactory.java)
or a path to a file in a jar file - it then contains the path to the jar file and the path to the file in the jar
(e.g. c:/jdk1.2.2/jre/lib/rt.jar|java/lang/Object.class or /Proj/rt.jar|java/lang/Object.class)
NOTE: This assumes that the resource path is the toString() of an IPath,
      in other words, it uses the IPath.SEPARATOR for file path
           and it uses '/' for entries in a zip file.
If not null, uses the given scope as a hint for getting Java project handles.
/**
	 * Creates an Openable handle from the given resource path.
	 * The resource path can be a path to a file in the workbench (e.g. /Proj/com/ibm/jdt/core/HandleFactory.java)
	 * or a path to a file in a jar file - it then contains the path to the jar file and the path to the file in the jar
	 * (e.g. c:/jdk1.2.2/jre/lib/rt.jar|java/lang/Object.class or /Proj/rt.jar|java/lang/Object.class)
	 * NOTE: This assumes that the resource path is the toString() of an IPath,
	 *       in other words, it uses the IPath.SEPARATOR for file path
	 *            and it uses '/' for entries in a zip file.
	 * If not null, uses the given scope as a hint for getting Java project handles.
	 */
	public Openable createOpenable(String resourcePath, IJavaSearchScope scope) {
		int separatorIndex;
		if ((separatorIndex= resourcePath.indexOf(IJavaSearchScope.JAR_FILE_ENTRY_SEPARATOR)) > -1) {
			// path to a class file inside a jar
			// Optimization: cache package fragment root handle and package handles
			int rootPathLength;
			PackageFragmentRoot root = null;
			if (this.lastPkgFragmentRootPath == null
					|| (rootPathLength = this.lastPkgFragmentRootPath.length()) != resourcePath.length()
					|| !resourcePath.regionMatches(0, this.lastPkgFragmentRootPath, 0, rootPathLength)) {
				String jarPath= resourcePath.substring(0, separatorIndex);
				root= getJarPkgFragmentRoot(resourcePath, separatorIndex, jarPath, scope);
				if (root == null)
					return null; // match is outside classpath
				this.lastPkgFragmentRootPath= jarPath;
				this.lastPkgFragmentRoot= root;
				this.packageHandles= new HashtableOfArrayToObject(5);
			}
			// create handle
			String module = null;
			String rootPath = this.lastPkgFragmentRoot.getPath().toOSString();
			if (org.eclipse.jdt.internal.compiler.util.Util.isJrt(rootPath)) {
				module = resourcePath.substring(separatorIndex + 1, 
						(separatorIndex = resourcePath.lastIndexOf(IJavaSearchScope.JAR_FILE_ENTRY_SEPARATOR)));
			}
			String classFilePath= resourcePath.substring(separatorIndex + 1);
			if (classFilePath.endsWith(TypeConstants.AUTOMATIC_MODULE_NAME))
				return root;
			String[] simpleNames = new Path(classFilePath).segments();
			String[] pkgName;
			int length = simpleNames.length-1;
			if (length > 0) {
				pkgName = new String[length];
				System.arraycopy(simpleNames, 0, pkgName, 0, length);
			} else {
				pkgName = CharOperation.NO_STRINGS;
			}
			IPackageFragment pkgFragment= (IPackageFragment) this.packageHandles.get(pkgName);
			if (pkgFragment == null) {
				pkgFragment= this.lastPkgFragmentRoot.getPackageFragment(pkgName, module);
				this.packageHandles.put(pkgName, pkgFragment);
			}
			IClassFile classFile= pkgFragment.getClassFile(simpleNames[length]);
			return (Openable) classFile;
		} else {
			// path to a file in a directory
			// Optimization: cache package fragment root handle and package handles
			int rootPathLength = -1;
			if (this.lastPkgFragmentRootPath == null
				|| !(resourcePath.startsWith(this.lastPkgFragmentRootPath)
					&& !org.eclipse.jdt.internal.compiler.util.Util.isExcluded(resourcePath.toCharArray(), this.lastPkgFragmentRoot.fullInclusionPatternChars(), this.lastPkgFragmentRoot.fullExclusionPatternChars(), false)
					&& (rootPathLength = this.lastPkgFragmentRootPath.length()) > 0
					&& resourcePath.charAt(rootPathLength) == '/')) {
				PackageFragmentRoot root= getPkgFragmentRoot(resourcePath);
				if (root == null)
					return null; // match is outside classpath
				this.lastPkgFragmentRoot = root;
				this.lastPkgFragmentRootPath = this.lastPkgFragmentRoot.internalPath().toString();
				this.packageHandles = new HashtableOfArrayToObject(5);
			}
			// create handle
			resourcePath = resourcePath.substring(this.lastPkgFragmentRootPath.length() + 1);
			String[] simpleNames = new Path(resourcePath).segments();
			String[] pkgName;
			int length = simpleNames.length-1;
			if (length > 0) {
				pkgName = new String[length];
				System.arraycopy(simpleNames, 0, pkgName, 0, length);
			} else {
				pkgName = CharOperation.NO_STRINGS;
			}
			IPackageFragment pkgFragment= (IPackageFragment) this.packageHandles.get(pkgName);
			if (pkgFragment == null) {
				pkgFragment= this.lastPkgFragmentRoot.getPackageFragment(pkgName);
				this.packageHandles.put(pkgName, pkgFragment);
			}
			String simpleName= simpleNames[length];
			if (org.eclipse.jdt.internal.core.util.Util.isJavaLikeFileName(simpleName)) {
				ICompilationUnit unit= pkgFragment.getCompilationUnit(simpleName);
				return (Openable) unit;
			} else if (org.eclipse.jdt.internal.compiler.util.Util.isClassFileName(simpleName)){
				IClassFile classFile= pkgFragment.getClassFile(simpleName);
				return (Openable) classFile;
			}
			return null;
		}
	}

	
Returns a handle denoting the class member identified by its scope.
/**
	 * Returns a handle denoting the class member identified by its scope.
	 */
	public IJavaElement createElement(ClassScope scope, ICompilationUnit unit, HashSet existingElements, HashMap knownScopes) {
		return createElement(scope, scope.referenceContext.sourceStart, unit, existingElements, knownScopes);
	}
	
Returns a handle denoting the lambda type identified by its scope.
/**
	 * Returns a handle denoting the lambda type identified by its scope.
	 */
	public IJavaElement createLambdaTypeElement(LambdaExpression expression, ICompilationUnit unit, HashSet existingElements, HashMap knownScopes) {
		return createElement(expression.scope, expression.sourceStart(), unit, existingElements, knownScopes).getParent();
	}
	protected void resolveDuplicates(IJavaElement handle) {

		// For anonymous source types, the occurrence count should be in the context
		// of the enclosing type.
		if (handle instanceof SourceType && ((SourceType) handle).isAnonymous()) {
			Object key = handle.getParent().getAncestor(IJavaElement.TYPE);
			int occurenceCount = this.localOccurrenceCounts.get(key);
			if (occurenceCount == -1)
				this.localOccurrenceCounts.put(key, 1);
			else {
				this.localOccurrenceCounts.put(key, ++occurenceCount);
				((SourceType)handle).localOccurrenceCount = occurenceCount;
			}
		}
	}
	
Create handle by adding child to parent obtained by recursing into parent scopes.
/**
	 * Create handle by adding child to parent obtained by recursing into parent scopes.
	 */
	public IJavaElement createElement(Scope scope, int elementPosition, ICompilationUnit unit, HashSet existingElements, HashMap knownScopes) {
		IJavaElement newElement = (IJavaElement)knownScopes.get(scope);
		if (newElement != null) return newElement;

		switch(scope.kind) {
			case Scope.COMPILATION_UNIT_SCOPE :
				newElement = unit;
				break;
			case Scope.CLASS_SCOPE :
				IJavaElement parentElement = createElement(scope.parent, elementPosition, unit, existingElements, knownScopes);
				switch (parentElement.getElementType()) {
					case IJavaElement.COMPILATION_UNIT :
						newElement = ((ICompilationUnit)parentElement).getType(new String(scope.enclosingSourceType().sourceName));
						break;
					case IJavaElement.TYPE :
						newElement = ((IType)parentElement).getType(new String(scope.enclosingSourceType().sourceName));
						break;
					case IJavaElement.FIELD :
					case IJavaElement.INITIALIZER :
					case IJavaElement.METHOD :
					    IMember member = (IMember)parentElement;
					    if (member.isBinary()) {
					        return null;
					    } else {
							newElement = member.getType(new String(scope.enclosingSourceType().sourceName), 1);
							// increment occurrence count if collision is detected
							if (newElement != null) {
								while (!existingElements.add(newElement)) ((SourceRefElement)newElement).occurrenceCount++;
							}
					    }
						break;
				}
				if (newElement != null) {
					knownScopes.put(scope, newElement);
				}
				break;
			case Scope.METHOD_SCOPE :
				if (scope.isLambdaScope()) {
					parentElement = createElement(scope.parent, elementPosition, unit, existingElements, knownScopes);
					LambdaExpression expression = (LambdaExpression) scope.originalReferenceContext();
					if (expression.resolvedType != null && expression.resolvedType.isValidBinding() && 
							!(expression.descriptor instanceof ProblemMethodBinding)) { // chain in lambda element only if resolved properly.
						//newElement = new org.eclipse.jdt.internal.core.SourceLambdaExpression((JavaElement) parentElement, expression).getMethod();
						newElement = LambdaFactory.createLambdaExpression((JavaElement) parentElement, expression).getMethod();
						knownScopes.put(scope, newElement);
						return newElement;
					}
					return parentElement;
				}
				IType parentType = (IType) createElement(scope.parent, elementPosition, unit, existingElements, knownScopes);
				MethodScope methodScope = (MethodScope) scope;
				if (methodScope.isInsideInitializer()) {
					// inside field or initializer, must find proper one
					TypeDeclaration type = methodScope.referenceType();
					int occurenceCount = 1;
					int length = type.fields == null ? 0 : type.fields.length;
					for (int i = 0; i < length; i++) {
						FieldDeclaration field = type.fields[i];
						if (field.declarationSourceStart <= elementPosition && elementPosition <= field.declarationSourceEnd) {
							switch (field.getKind()) {
								case AbstractVariableDeclaration.FIELD :
								case AbstractVariableDeclaration.ENUM_CONSTANT :
									newElement = parentType.getField(new String(field.name));
									break;
								case AbstractVariableDeclaration.INITIALIZER :
									newElement = parentType.getInitializer(occurenceCount);
									break;
							}
							break;
						} else if (field.getKind() == AbstractVariableDeclaration.INITIALIZER) {
							occurenceCount++;
						}
					}
				} else {
					// method element
					AbstractMethodDeclaration method = methodScope.referenceMethod();
					newElement = parentType.getMethod(new String(method.selector), Util.typeParameterSignatures(method));
					if (newElement != null) {
						knownScopes.put(scope, newElement);
					}
				}
				break;
			case Scope.BLOCK_SCOPE :
				// standard block, no element per se
				newElement = createElement(scope.parent, elementPosition, unit, existingElements, knownScopes);
				break;
		}
		resolveDuplicates(newElement);
		return newElement;
	}
	
Returns the package fragment root that corresponds to the given jar path.
See createOpenable(...) for the format of the jar path string.
If not null, uses the given scope as a hint for getting Java project handles.
/**
	 * Returns the package fragment root that corresponds to the given jar path.
	 * See createOpenable(...) for the format of the jar path string.
	 * If not null, uses the given scope as a hint for getting Java project handles.
	 */
	private PackageFragmentRoot getJarPkgFragmentRoot(String resourcePathString, int jarSeparatorIndex, String jarPathString, IJavaSearchScope scope) {

		IPath jarPath= new Path(jarPathString);

		Object target = JavaModel.getTarget(jarPath, false);
		if (target instanceof IFile) {
			// internal jar: is it on the classpath of its project?
			//  e.g. org.eclipse.swt.win32/ws/win32/swt.jar
			//        is NOT on the classpath of org.eclipse.swt.win32
			IFile jarFile = (IFile)target;
			JavaProject javaProject = (JavaProject) this.javaModel.getJavaProject(jarFile);
			try {
				IClasspathEntry entry = javaProject.getClasspathEntryFor(jarPath);
				if (entry != null) {
					return (PackageFragmentRoot) javaProject.getPackageFragmentRoot(jarFile);
				}
			} catch (JavaModelException e) {
				// ignore and try to find another project
			}
		}

		// walk projects in the scope and find the first one that has the given jar path in its classpath
		IJavaProject[] projects;
		if (scope != null) {
			if (scope instanceof AbstractJavaSearchScope) {
				PackageFragmentRoot root = (PackageFragmentRoot) ((AbstractJavaSearchScope) scope).packageFragmentRoot(resourcePathString, jarSeparatorIndex, jarPathString);
				if (root != null)
					return root;
			} else {
				IPath[] enclosingProjectsAndJars = scope.enclosingProjectsAndJars();
				int length = enclosingProjectsAndJars.length;
				projects = new IJavaProject[length];
				int index = 0;
				for (int i = 0; i < length; i++) {
					IPath path = enclosingProjectsAndJars[i];
					if (path.segmentCount() == 1) {
						projects[index++] = this.javaModel.getJavaProject(path.segment(0));
					}
				}
				if (index < length) {
					System.arraycopy(projects, 0, projects = new IJavaProject[index], 0, index);
				}
				PackageFragmentRoot root = getJarPkgFragmentRoot(jarPath, target, projects);
				if (root != null) {
					return root;
				}
			}
		}

		// not found in the scope, walk all projects
		try {
			projects = this.javaModel.getJavaProjects();
		} catch (JavaModelException e) {
			// java model is not accessible
			return null;
		}
		return getJarPkgFragmentRoot(jarPath, target, projects);
	}

	private PackageFragmentRoot getJarPkgFragmentRoot(
		IPath jarPath,
		Object target,
		IJavaProject[] projects) {
		for (int i= 0, projectCount= projects.length; i < projectCount; i++) {
			try {
				JavaProject javaProject= (JavaProject)projects[i];
				IClasspathEntry classpathEnty = javaProject.getClasspathEntryFor(jarPath);
				if (classpathEnty != null) {
					if (target instanceof IFile) {
						// internal jar
						return (PackageFragmentRoot) javaProject.getPackageFragmentRoot((IFile)target, null, classpathEnty.getExtraAttributes());
					} else {
						// external jar
						return (PackageFragmentRoot) javaProject.getPackageFragmentRoot0(jarPath, classpathEnty.getExtraAttributes());
					}
				}
			} catch (JavaModelException e) {
				// JavaModelException from getResolvedClasspath - a problem occurred while accessing project: nothing we can do, ignore
			}
		}
		return null;
	}

	
Returns the package fragment root that contains the given resource path.
/**
	 * Returns the package fragment root that contains the given resource path.
	 */
	private PackageFragmentRoot getPkgFragmentRoot(String pathString) {

		IPath path= new Path(pathString);
		IProject[] projects= ResourcesPlugin.getWorkspace().getRoot().getProjects();
		for (int i= 0, max= projects.length; i < max; i++) {
			try {
				IProject project = projects[i];
				if (!project.isAccessible()
					|| !project.hasNature(JavaCore.NATURE_ID)) continue;
				IJavaProject javaProject= this.javaModel.getJavaProject(project);
				IPackageFragmentRoot[] roots= javaProject.getPackageFragmentRoots();
				for (int j= 0, rootCount= roots.length; j < rootCount; j++) {
					PackageFragmentRoot root= (PackageFragmentRoot)roots[j];
					if (root.internalPath().isPrefixOf(path) && !Util.isExcluded(path, root.fullInclusionPatternChars(), root.fullExclusionPatternChars(), false)) {
						return root;
					}
				}
			} catch (CoreException e) {
				// CoreException from hasNature - should not happen since we check that the project is accessible
				// JavaModelException from getPackageFragmentRoots - a problem occured while accessing project: nothing we can do, ignore
			}
		}
		return null;
	}

}