/*
* Copyright 2013 the original author or authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.gradle.model.internal.core;
import com.google.common.annotations.VisibleForTesting;
import com.google.common.base.CharMatcher;
import com.google.common.collect.Iterables;
import com.google.common.collect.Iterators;
import com.google.common.collect.Lists;
import net.jcip.annotations.ThreadSafe;
import org.gradle.api.GradleException;
import org.gradle.api.Nullable;
import org.gradle.internal.exceptions.Contextual;
import java.util.Iterator;
import java.util.List;
import java.util.StringTokenizer;
import java.util.WeakHashMap;
import static java.lang.System.arraycopy;
@ThreadSafe
public class ModelPath implements Iterable<String>, Comparable<ModelPath> {
private static final String SEPARATOR = ".";
private static final CharMatcher VALID_FIRST_CHAR_MATCHER = CharMatcher.inRange('a', 'z').or(CharMatcher.inRange('A', 'Z')).or(CharMatcher.is('_'));
private final static CharMatcher INVALID_FIRST_CHAR_MATCHER = VALID_FIRST_CHAR_MATCHER.negate().precomputed();
private final static CharMatcher INVALID_CHAR_MATCHER = CharMatcher.inRange('0', '9').or(VALID_FIRST_CHAR_MATCHER).or(CharMatcher.is('-')).negate().precomputed();
public static final ModelPath ROOT;
private static final Cache BY_PATH;
static {
ROOT = new ModelPath("", new String[0]) {
@Override
public String toString() {
return "<root>";
}
};
BY_PATH = new Cache(ROOT);
}
private final String path;
private final String[] components;
private final ModelPath parent;
public ModelPath(String path) {
this(path, splitPath(path));
}
private ModelPath(String path, String[] components) {
// one should really avoid using this constructor as it is totally inefficient
// and reserved to spurious cases when the components have dots in names
// (and this can happen if a task name contains dots)
this.path = path;
this.components = components;
this.parent = doGetParent();
}
@Override
public int compareTo(ModelPath other) {
if (this == other) {
return 0;
}
return path.compareTo(other.path);
}
@Override
public boolean equals(Object o) {
if (this == o) {
return true;
}
if (o == null || getClass() != o.getClass()) {
return false;
}
ModelPath modelPath = (ModelPath) o;
return components.length == modelPath.components.length && path.equals(modelPath.path);
}
@Override
public int hashCode() {
return path.hashCode();
}
@Override
public Iterator<String> iterator() {
return Iterators.forArray(components);
}
public String getPath() {
return path;
}
@Override
public String toString() {
return path;
}
public static ModelPath path(String path) {
return BY_PATH.get(path);
}
@VisibleForTesting
static ModelPath path(Iterable<String> names) {
String[] components = Iterables.toArray(names, String.class);
String path = pathString(components);
return path(path, components);
}
private static ModelPath path(String path, String[] names) {
for (String name : names) {
if (name.indexOf('.') >= 0) {
return new ModelPath(path, names);
}
}
return BY_PATH.get(path, names);
}
public static String pathString(String... names) {
if (names.length == 0) {
return "";
}
StringBuilder builder = new StringBuilder();
for (int i = 0, len = names.length; i < len; i++) {
if (i != 0) {
builder.append(".");
}
builder.append(names[i]);
}
return builder.toString();
}
public ModelPath child(String child) {
if (this.components.length == 0) {
return path(child, new String[] {child});
}
String[] childComponents = new String[components.length + 1];
arraycopy(components, 0, childComponents, 0, components.length);
childComponents[components.length] = child;
return path(path + "." + child, childComponents);
}
public ModelPath getRootParent() {
return components.length <= 1 ? null : ModelPath.path(components[0]);
}
@Nullable
public ModelPath getParent() {
return parent;
}
private ModelPath doGetParent() {
if (components.length == 0) {
return null;
}
if (components.length == 1) {
return ROOT;
}
String[] parentComponents = new String[components.length - 1];
arraycopy(components, 0, parentComponents, 0, components.length - 1);
// Same as the length of this, minus the last element, minus the dot between them
int parentPathLength = path.length() - components[components.length - 1].length() - 1;
return path(path.substring(0, parentPathLength), parentComponents);
}
public String getName() {
if (components.length == 0) {
return "";
}
return components[components.length - 1];
}
public boolean isDirectChild(@Nullable ModelPath other) {
if (other == null) {
return false;
}
if (other.components.length != components.length + 1) {
return false;
}
ModelPath otherParent = other.getParent();
return otherParent != null && otherParent.equals(this);
}
public boolean isDescendant(@Nullable ModelPath other) {
if (other == null) {
return false;
}
int length = components.length;
if (other.components.length <= components.length) {
return false;
}
for (int i = 0; i < length; i++) {
if (!components[i].equals(other.components[i])) {
return false;
}
}
return true;
}
public ModelPath descendant(ModelPath path) {
if (components.length == 0) {
return path;
}
if (path.components.length == 0) {
return this;
}
String[] descendantComponents = new String[components.length + path.components.length];
arraycopy(components, 0, descendantComponents, 0, components.length);
arraycopy(path.components, 0, descendantComponents, components.length, path.components.length);
return path(this.path + "." + path.getPath(), descendantComponents);
}
public static class InvalidNameException extends GradleException {
public InvalidNameException(String message) {
super(message);
}
}
@Contextual
public static class InvalidPathException extends GradleException {
public InvalidPathException(String message, InvalidNameException e) {
super(message, e);
}
}
public static void validateName(String name) {
if (name.isEmpty()) {
throw new InvalidNameException("Cannot use an empty string as a model element name.");
}
char firstChar = name.charAt(0);
if (INVALID_FIRST_CHAR_MATCHER.matches(firstChar)) {
throw new InvalidNameException(String.format("Model element name '%s' has illegal first character '%s' (names must start with an ASCII letter or underscore).", name, firstChar));
}
for (int i = 1; i < name.length(); ++i) {
char character = name.charAt(i);
if (INVALID_CHAR_MATCHER.matches(character)) {
throw new InvalidNameException(String.format("Model element name '%s' contains illegal character '%s' (only ASCII letters, numbers and the underscore are allowed).", name, character));
}
}
}
@Nullable
public static ModelPath validatedPath(@Nullable String path) {
if (path == null) {
return null;
} else {
validatePath(path);
return path(path);
}
}
public static ModelPath nonNullValidatedPath(String path) {
if (path == null) {
throw new IllegalArgumentException("path cannot be null");
} else {
return validatedPath(path);
}
}
public static void validatePath(String path) throws InvalidPathException {
if (path.isEmpty()) {
throw new InvalidPathException("Cannot use an empty string as a model path.", null);
}
if (path.startsWith(SEPARATOR)) {
throw new InvalidPathException(String.format("Model path '%s' cannot start with name separator '%s'.", path, SEPARATOR), null);
}
if (path.endsWith(SEPARATOR)) {
throw new InvalidPathException(String.format("Model path '%s' cannot end with name separator '%s'.", path, SEPARATOR), null);
}
String[] names = splitPath(path);
if (names.length == 1) {
validateName(names[0]);
} else {
for (String name : names) {
try {
validateName(name);
} catch (InvalidNameException e) {
throw new InvalidPathException(String.format("Model path '%s' is invalid due to invalid name component.", path), e);
}
}
}
}
private static String[] splitPath(String path) {
// Let's make sure we never need to reallocate
List<String> components = Lists.newArrayListWithCapacity(path.length());
StringTokenizer tokenizer = new StringTokenizer(path, ".");
while (tokenizer.hasMoreTokens()) {
String component = tokenizer.nextToken();
if (component.isEmpty()) {
continue;
}
components.add(component);
}
return components.toArray(new String[components.size()]);
}
private static class Cache {
private final WeakHashMap<String, ModelPath> cache = new WeakHashMap<String, ModelPath>();
public Cache(ModelPath root) {
cache.put(root.path, root);
}
public synchronized ModelPath get(String path) {
ModelPath result = cache.get(path);
if (result != null) {
return result;
}
result = new ModelPath(path);
cache.put(path, result);
return result;
}
public synchronized ModelPath get(String path, String[] names) {
ModelPath result = cache.get(path);
if (result != null) {
return result;
}
result = new ModelPath(path, names);
cache.put(path, result);
return result;
}
}
}