/*******************************************************************************
 * 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
 *     Stephan Herrmann - Contribution for
 *								Bug 458577 - IClassFile.getWorkingCopy() may lead to NPE in BecomeWorkingCopyOperation
 *								Bug 440477 - [null] Infrastructure for feeding external annotations into compilation
 *								Bug 462768 - [null] NPE when using linked folder for external annotations
 *******************************************************************************/
package org.eclipse.jdt.internal.core;

import java.io.IOException;
import java.util.HashMap;
import java.util.Map;
import java.util.zip.ZipFile;

import org.eclipse.core.resources.IProject;
import org.eclipse.core.resources.IResource;
import org.eclipse.core.resources.IWorkspaceRoot;
import org.eclipse.core.runtime.CoreException;
import org.eclipse.core.runtime.IPath;
import org.eclipse.core.runtime.IProgressMonitor;
import org.eclipse.core.runtime.IStatus;
import org.eclipse.core.runtime.Path;
import org.eclipse.core.runtime.Status;
import org.eclipse.jdt.core.*;
import org.eclipse.jdt.internal.compiler.classfmt.ClassFileReader;
import org.eclipse.jdt.internal.compiler.classfmt.ClassFormatException;
import org.eclipse.jdt.internal.compiler.classfmt.ExternalAnnotationDecorator;
import org.eclipse.jdt.internal.compiler.classfmt.ExternalAnnotationProvider;
import org.eclipse.jdt.internal.compiler.env.IBinaryType;
import org.eclipse.jdt.internal.compiler.env.IDependent;
import org.eclipse.jdt.internal.compiler.env.IModule;
import org.eclipse.jdt.internal.compiler.util.SuffixConstants;
import org.eclipse.jdt.internal.core.nd.java.JavaNames;
import org.eclipse.jdt.internal.core.nd.java.model.BinaryTypeDescriptor;
import org.eclipse.jdt.internal.core.nd.java.model.BinaryTypeFactory;
import org.eclipse.jdt.internal.core.nd.util.CharArrayUtils;
import org.eclipse.jdt.internal.core.util.MementoTokenizer;
import org.eclipse.jdt.internal.core.util.Util;

/**
 * @see IClassFile
 */

@SuppressWarnings({"rawtypes"})
public class ClassFile extends AbstractClassFile implements IOrdinaryClassFile {

	protected BinaryType binaryType = null;

	private IPath externalAnnotationBase;

/*
 * Creates a handle to a class file.
 */
protected ClassFile(PackageFragment parent, String nameWithoutExtension) {
	super(parent, nameWithoutExtension);
}

/**
 * Creates the children elements for this class file adding the resulting
 * new handles and info objects to the newElements table. Returns true
 * if successful, or false if an error is encountered parsing the class file.
 *
 * @see Openable
 * @see Signature
 */
@Override
protected boolean buildStructure(OpenableElementInfo info, IProgressMonitor pm, Map newElements, IResource underlyingResource) throws JavaModelException {
	IBinaryType typeInfo = getBinaryTypeInfo();
	if (typeInfo == null) {
		// The structure of a class file is unknown if a class file format errors occurred
		//during the creation of the diet class file representative of this ClassFile.
		info.setChildren(JavaElement.NO_ELEMENTS);
		return false;
	}
	
	// Make the type
	IType type = getType();
	info.setChildren(new IJavaElement[] {type});
	newElements.put(type, typeInfo);
	// Read children
	((ClassFileInfo) info).readBinaryChildren(this, (HashMap) newElements, typeInfo);
	return true;
}

@Override
public void codeComplete(int offset, CompletionRequestor requestor, WorkingCopyOwner owner, IProgressMonitor monitor) throws JavaModelException {
	String source = getSource();
	if (source != null) {
		BinaryType type = (BinaryType) getType();
		BasicCompilationUnit cu =
			new BasicCompilationUnit(
				getSource().toCharArray(),
				null,
				type.sourceFileName((IBinaryType) type.getElementInfo()),
				getJavaProject()); // use project to retrieve corresponding .java IFile
		codeComplete(cu, cu, offset, requestor, owner, null/*extended context isn't computed*/, monitor);
	}
}

/**
 * @see ICodeAssist#codeSelect(int, int, WorkingCopyOwner)
 */
@Override
public IJavaElement[] codeSelect(int offset, int length, WorkingCopyOwner owner) throws JavaModelException {
	IBuffer buffer = getBuffer();
	char[] contents;
	if (buffer != null && (contents = buffer.getCharacters()) != null) {
	    BinaryType type = (BinaryType) getType();
		BasicCompilationUnit cu = new BasicCompilationUnit(contents, null, type.sourceFileName((IBinaryType) type.getElementInfo()), this);
		return super.codeSelect(cu, offset, length, owner);
	} else {
		//has no associated souce
		return new IJavaElement[] {};
	}
}
public boolean existsUsingJarTypeCache() {
	if (getPackageFragmentRoot().isArchive()) {
		JavaModelManager manager = JavaModelManager.getJavaModelManager();
		IType type = getType();
		Object info = manager.getInfo(type);
		if (info == JavaModelCache.NON_EXISTING_JAR_TYPE_INFO)
			return false;
		else if (info != null)
			return true;
		// info is null
		JavaElementInfo parentInfo = (JavaElementInfo) manager.getInfo(getParent());
		if (parentInfo != null) {
			// if parent is open, this class file must be in its children
			IJavaElement[] children = parentInfo.getChildren();
			for (int i = 0, length = children.length; i < length; i++) {
				IJavaElement child = children[i];
				if (child instanceof ClassFile && this.name.equals(((ClassFile) child).name))
					return true;
			}
			return false;
		}
		try {
			info = getJarBinaryTypeInfo();
		} catch (CoreException e) {
			// leave info null
		} catch (IOException e) {
			// leave info null
		} catch (ClassFormatException e) {
			// leave info null
		}
		manager.putJarTypeInfo(type, info == null ? JavaModelCache.NON_EXISTING_JAR_TYPE_INFO : info);
		return info != null;
	} else
		return exists();
}

/**
 * @see ITypeRoot#findPrimaryType()
 */
@Override
public IType findPrimaryType() {
	IType primaryType= getType();
	if (primaryType.exists()) {
		return primaryType;
	}
	return null;
}
@Override
public String getAttachedJavadoc(IProgressMonitor monitor) throws JavaModelException {
	return getType().getAttachedJavadoc(monitor);
}
/**
 * Returns the <code>ClassFileReader</code>specific for this IClassFile, based
 * on its underlying resource, or <code>null</code> if unable to create
 * the diet class file.
 * There are two cases to consider:<ul>
 * <li>a class file corresponding to an IFile resource</li>
 * <li>a class file corresponding to a zip entry in a JAR</li>
 * </ul>
 *
 * @exception JavaModelException when the IFile resource or JAR is not available
 * or when this class file is not present in the JAR
 */
public IBinaryType getBinaryTypeInfo() throws JavaModelException {
	try {
		IBinaryType info = getJarBinaryTypeInfo();
		if (info == null) {
			throw newNotPresentException();
		}
		return info;
	} catch (ClassFormatException cfe) {
		//the structure remains unknown
		if (JavaCore.getPlugin().isDebugging()) {
			cfe.printStackTrace(System.err);
		}
		return null;
	} catch (IOException ioe) {
		throw new JavaModelException(ioe, IJavaModelStatusConstants.IO_EXCEPTION);
	} catch (CoreException e) {
		if (e instanceof JavaModelException) {
			throw (JavaModelException)e;
		} else {
			throw new JavaModelException(e);
		}
	}
}

public String getName() {
	return this.name;
}

private IBinaryType getJarBinaryTypeInfo() throws CoreException, IOException, ClassFormatException {
	BinaryTypeDescriptor descriptor = BinaryTypeFactory.createDescriptor(this);

	if (descriptor == null) {
		return null;
	}
	IBinaryType result = null;
	IPackageFragmentRoot root = getPackageFragmentRoot();
	if (getPackageFragmentRoot() instanceof JarPackageFragmentRoot) {
		if (root instanceof JrtPackageFragmentRoot || this.name.equals(IModule.MODULE_INFO)) {
			PackageFragment pkg = (PackageFragment) getParent();
			JarPackageFragmentRoot jarRoot = (JarPackageFragmentRoot) getPackageFragmentRoot();
			String entryName = jarRoot.getClassFilePath(Util.concatWith(pkg.names, getElementName(), '/'));
			byte[] contents = getClassFileContent(jarRoot, entryName);
			if (contents != null) {
				String fileName = root.getHandleIdentifier() + IDependent.JAR_FILE_ENTRY_SEPARATOR + entryName;
				result = new ClassFileReader(contents, fileName.toCharArray(), false);
			}
		} else {
			result = BinaryTypeFactory.readType(descriptor, null);
		}
	} else {
		result = BinaryTypeFactory.readType(descriptor, null);
	}
		
	if (result == null) {
		return null;
	}

	// TODO(sxenos): setup the external annotation provider if the IBinaryType came from the index
	if (root.getKind() == IPackageFragmentRoot.K_BINARY) {
		JavaProject javaProject = (JavaProject) getAncestor(IJavaElement.JAVA_PROJECT);
		IClasspathEntry entry;
		try {
			entry = javaProject.getClasspathEntryFor(getPath());
		} catch (JavaModelException jme) {
			// Access via cached ClassFile/PF/PFR of a closed project?
			// Ignore and continue with result undecorated
			return result;
		}
		if (entry != null) {
			PackageFragment pkg = (PackageFragment) getParent();
			String entryName = Util.concatWith(pkg.names, getElementName(), '/');
			entryName = new String(CharArrayUtils.concat(
					JavaNames.fieldDescriptorToBinaryName(descriptor.fieldDescriptor), SuffixConstants.SUFFIX_CLASS));
			IProject project = javaProject.getProject();
			IPath externalAnnotationPath = ClasspathEntry.getExternalAnnotationPath(entry, project, false); // unresolved for use in ExternalAnnotationTracker
			if (externalAnnotationPath != null) {
				result = setupExternalAnnotationProvider(project, externalAnnotationPath, result, 
						entryName.substring(0, entryName.length() - SuffixConstants.SUFFIX_CLASS.length));
			} else if (entry.getEntryKind() == IClasspathEntry.CPE_SOURCE) {
				result = new ExternalAnnotationDecorator(result, true);
			}
		}
	}

	return result;
}

private IBinaryType setupExternalAnnotationProvider(IProject project, final IPath externalAnnotationPath,
		IBinaryType reader, final String typeName)
{
	IBinaryType result = reader;
	// try resolve path within the workspace:
	IWorkspaceRoot root = project.getWorkspace().getRoot();
	IResource resource;
	if (externalAnnotationPath.segmentCount() == 1) {
		resource = root.getProject(externalAnnotationPath.lastSegment());
	} else {
		resource = root.getFolder(externalAnnotationPath);
		if (!resource.exists())
			resource = root.getFile(externalAnnotationPath);
	}
	String resolvedPath;
	if (resource.exists()) {
		if (resource.isVirtual()) {
			Util.log(new Status(IStatus.ERROR, JavaCore.PLUGIN_ID,
					"Virtual resource "+externalAnnotationPath+" cannot be used as annotationpath for project "+project.getName())); //$NON-NLS-1$ //$NON-NLS-2$
			return reader;
		}
		resolvedPath = resource.getLocation().toString(); // workspace lookup succeeded -> resolve it
	} else {
		resolvedPath = externalAnnotationPath.toString(); // not in workspace, use as is
	}
	ZipFile annotationZip = null;
	try {
		annotationZip = ExternalAnnotationDecorator.getAnnotationZipFile(resolvedPath, new ExternalAnnotationDecorator.ZipFileProducer() {
			@Override public ZipFile produce() throws IOException {
				try {
					return JavaModelManager.getJavaModelManager().getZipFile(externalAnnotationPath); // use (absolute, but) unresolved path here
				} catch (CoreException e) {
					throw new IOException("Failed to read annotation file for "+typeName+" from "+externalAnnotationPath.toString(), e); //$NON-NLS-1$ //$NON-NLS-2$
				}
			}});

		ExternalAnnotationProvider annotationProvider = ExternalAnnotationDecorator
				.externalAnnotationProvider(resolvedPath, typeName, annotationZip);
		result = new ExternalAnnotationDecorator(reader, annotationProvider);
	} catch (IOException e) {
		Util.log(e);
		return result;
	} finally {
		if (annotationZip != null)
			JavaModelManager.getJavaModelManager().closeZipFile(annotationZip);
	}
	if (annotationZip == null) {
		// Additional change listening for individual types only when annotations are in individual files.
		// Note that we also listen for classes that don't yet have an annotation file, to detect its creation
		this.externalAnnotationBase = externalAnnotationPath; // remember so we can unregister later
		ExternalAnnotationTracker.registerClassFile(externalAnnotationPath, new Path(typeName), this);
	}
	return result;
}
void closeAndRemoveFromJarTypeCache() throws JavaModelException {
	super.close();
	// triggered when external annotations have changed we need to recreate this class file
	JavaModelManager.getJavaModelManager().removeFromJarTypeCache(this.binaryType);
}
@Override
public void close() throws JavaModelException {
	if (this.externalAnnotationBase != null) {
		String entryName = Util.concatWith(((PackageFragment) getParent()).names, this.name, '/');
		ExternalAnnotationTracker.unregisterClassFile(this.externalAnnotationBase, new Path(entryName));
	}
	super.close();
}
/**
 * @see IMember
 */
@Override
public IClassFile getClassFile() {
	return this;
}
/**
 * @see IClassFile
 */
@Override
public IJavaElement getElementAt(int position) throws JavaModelException {
	IJavaElement parentElement = getParent();
	while (parentElement.getElementType() != IJavaElement.PACKAGE_FRAGMENT_ROOT) {
		parentElement = parentElement.getParent();
	}
	PackageFragmentRoot root = (PackageFragmentRoot) parentElement;
	SourceMapper mapper = root.getSourceMapper();
	if (mapper == null) {
		return null;
	} else {
		// ensure this class file's buffer is open so that source ranges are computed
		getBuffer();

		IType type = getType();
		return findElement(type, position, mapper);
	}
}

/*
 * @see JavaElement
 */
@Override
public IJavaElement getHandleFromMemento(String token, MementoTokenizer memento, WorkingCopyOwner owner) {
	switch (token.charAt(0)) {
		case JEM_TYPE:
			if (!memento.hasMoreTokens()) return this;
			String typeName = memento.nextToken();
			JavaElement type = new BinaryType(this, typeName);
			return type.getHandleFromMemento(memento, owner);
	}
	return null;
}
/**
 * @see JavaElement#getHandleMemento()
 */
@Override
protected char getHandleMementoDelimiter() {
	return JavaElement.JEM_CLASSFILE;
}
/*
 * Returns the name of the toplevel type of this class file.
 */
public String getTopLevelTypeName() {
    String topLevelTypeName = getElementName();
    int firstDollar = topLevelTypeName.indexOf('$');
    if (firstDollar != -1) {
        topLevelTypeName = topLevelTypeName.substring(0, firstDollar);
    } else {
        topLevelTypeName = topLevelTypeName.substring(0, topLevelTypeName.length()-SUFFIX_CLASS.length);
    }
    return topLevelTypeName;
}
/**
 * @see IClassFile
 */
@Override
public IType getType() {
	if (this.binaryType == null) {
		this.binaryType = new BinaryType(this, getTypeName());
	}
	return this.binaryType;
}
public String getTypeName() {
	// Internal class file name doesn't contain ".class" file extension
	int lastDollar = this.name.lastIndexOf('$');
	return lastDollar > -1 ? Util.localTypeName(this.name, lastDollar, this.name.length()) : this.name;
}
/*
 * @see IClassFile
 */
@Override
public ICompilationUnit getWorkingCopy(WorkingCopyOwner owner, IProgressMonitor monitor) throws JavaModelException {
	CompilationUnit workingCopy = new ClassFileWorkingCopy(this, owner == null ? DefaultWorkingCopyOwner.PRIMARY : owner);
	JavaModelManager manager = JavaModelManager.getJavaModelManager();
	JavaModelManager.PerWorkingCopyInfo perWorkingCopyInfo =
		manager.getPerWorkingCopyInfo(workingCopy, false/*don't create*/, true/*record usage*/, null/*not used since don't create*/);
	if (perWorkingCopyInfo != null) {
		return perWorkingCopyInfo.getWorkingCopy(); // return existing handle instead of the one created above
	}
	BecomeWorkingCopyOperation op = new BecomeWorkingCopyOperation(workingCopy, null);
	op.runOperation(monitor);
	return workingCopy;
}
/**
 * @see IClassFile
 */
@Override
public boolean isClass() throws JavaModelException {
	return getType().isClass();
}
/**
 * @see IClassFile
 */
@Override
public boolean isInterface() throws JavaModelException {
	return getType().isInterface();
}
/**
 * Opens and returns buffer on the source code associated with this class file.
 * Maps the source code to the children elements of this class file.
 * If no source code is associated with this class file,
 * <code>null</code> is returned.
 *
 * @see Openable
 */
@Override
protected IBuffer openBuffer(IProgressMonitor pm, Object info) throws JavaModelException {
	// Check the cache for the top-level type first
	IType outerMostEnclosingType = getOuterMostEnclosingType();
	IBuffer buffer = getBufferManager().getBuffer(outerMostEnclosingType.getClassFile());
	if (buffer == null) {
		SourceMapper mapper = getSourceMapper();
		IBinaryType typeInfo = info instanceof IBinaryType ? (IBinaryType) info : null;
		if (mapper != null) {
			buffer = mapSource(mapper, typeInfo, outerMostEnclosingType.getClassFile());
		}
	}
	return buffer;
}
/** Loads the buffer via SourceMapper, and maps it in SourceMapper */
private IBuffer mapSource(SourceMapper mapper, IBinaryType info, IClassFile bufferOwner) {
	char[] contents = mapper.findSource(getType(), info);
	if (contents != null) {
		// create buffer
		IBuffer buffer = BufferManager.createBuffer(bufferOwner);
		if (buffer == null) return null;
		BufferManager bufManager = getBufferManager();
		bufManager.addBuffer(buffer);

		// set the buffer source
		if (buffer.getCharacters() == null){
			buffer.setContents(contents);
		}

		// listen to buffer changes
		buffer.addBufferChangedListener(this);

		// do the source mapping
		mapper.mapSource((NamedMember) getOuterMostEnclosingType(), contents, info);

		return buffer;
	} else {
		// create buffer
		IBuffer buffer = BufferManager.createNullBuffer(bufferOwner);
		if (buffer == null) return null;
		BufferManager bufManager = getBufferManager();
		bufManager.addBuffer(buffer);

		// listen to buffer changes
		buffer.addBufferChangedListener(this);
		return buffer;
	}
}
/* package */ static String simpleName(char[] className) {
	if (className == null)
		return null;
	String simpleName = new String(unqualifiedName(className));
	int lastDollar = simpleName.lastIndexOf('$');
	if (lastDollar != -1)
		return Util.localTypeName(simpleName, lastDollar, simpleName.length());
	else
		return simpleName;
}

/** Returns the type of the top-level declaring class used to find the source code */
private IType getOuterMostEnclosingType() {
	IType type = getType();
	IType enclosingType = type.getDeclaringType();
	while (enclosingType != null) {
		type = enclosingType;
		enclosingType = type.getDeclaringType();
	}
	return type;
}

/**
 * Returns the Java Model representation of the given name
 * which is provided in diet class file format, or <code>null</code>
 * if the given name is <code>null</code>.
 *
 * <p><code>ClassFileReader</code> format is similar to "java/lang/Object",
 * and corresponding Java Model format is "java.lang.Object".
 */

public static char[] translatedName(char[] name) {
	if (name == null)
		return null;
	int nameLength = name.length;
	char[] newName= new char[nameLength];
	for (int i= 0; i < nameLength; i++) {
		if (name[i] == '/') {
			newName[i]= '.';
		} else {
			newName[i]= name[i];
		}
	}
	return newName;
}
/**
 * Returns the Java Model representation of the given names
 * which are provided in diet class file format, or <code>null</code>
 * if the given names are <code>null</code>.
 *
 * <p><code>ClassFileReader</code> format is similar to "java/lang/Object",
 * and corresponding Java Model format is "java.lang.Object".
 */

/* package */ static char[][] translatedNames(char[][] names) {
	if (names == null)
		return null;
	int length = names.length;
	char[][] newNames = new char[length][];
	for(int i = 0; i < length; i++) {
		newNames[i] = translatedName(names[i]);
	}
	return newNames;
}
/**
 * Returns the Java Model format of the unqualified class name for the
 * given className which is provided in diet class file format,
 * or <code>null</code> if the given className is <code>null</code>.
 * (This removes the package name, but not enclosing type names).
 *
 * <p><code>ClassFileReader</code> format is similar to "java/lang/Object",
 * and corresponding Java Model simple name format is "Object".
 */

/* package */ static char[] unqualifiedName(char[] className) {
	if (className == null)
		return null;
	int count = 0;
	for (int i = className.length - 1; i > -1; i--) {
		if (className[i] == '/') {
			char[] name = new char[count];
			System.arraycopy(className, i + 1, name, 0, count);
			return name;
		}
		count++;
	}
	return className;
}
}