1 /* 2 * Copyright (C) 2012 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 package com.android.tools.lint.checks; 18 19 import static com.android.tools.lint.detector.api.LintConstants.ANDROID_PKG_PREFIX; 20 import static com.android.tools.lint.detector.api.LintConstants.ANDROID_URI; 21 import static com.android.tools.lint.detector.api.LintConstants.AUTO_URI; 22 import static com.android.tools.lint.detector.api.LintConstants.URI_PREFIX; 23 import static com.android.tools.lint.detector.api.LintConstants.XMLNS_PREFIX; 24 25 import com.android.tools.lint.detector.api.Category; 26 import com.android.tools.lint.detector.api.Issue; 27 import com.android.tools.lint.detector.api.LayoutDetector; 28 import com.android.tools.lint.detector.api.LintUtils; 29 import com.android.tools.lint.detector.api.Scope; 30 import com.android.tools.lint.detector.api.Severity; 31 import com.android.tools.lint.detector.api.Speed; 32 import com.android.tools.lint.detector.api.XmlContext; 33 34 import org.w3c.dom.Attr; 35 import org.w3c.dom.Document; 36 import org.w3c.dom.Element; 37 import org.w3c.dom.NamedNodeMap; 38 import org.w3c.dom.Node; 39 import org.w3c.dom.NodeList; 40 41 import java.util.HashMap; 42 import java.util.Map; 43 44 /** 45 * Checks for various issues related to XML namespaces 46 */ 47 public class NamespaceDetector extends LayoutDetector { 48 /** Typos in the namespace */ 49 public static final Issue TYPO = Issue.create( 50 "NamespaceTypo", //$NON-NLS-1$ 51 "Looks for misspellings in namespace declarations", 52 53 "Accidental misspellings in namespace declarations can lead to some very " + 54 "obscure error messages. This check looks for potential misspellings to " + 55 "help track these down.", 56 Category.CORRECTNESS, 57 8, 58 Severity.WARNING, 59 NamespaceDetector.class, 60 Scope.RESOURCE_FILE_SCOPE); 61 62 /** Unused namespace declarations */ 63 public static final Issue UNUSED = Issue.create( 64 "UnusedNamespace", //$NON-NLS-1$ 65 "Finds unused namespaces in XML documents", 66 67 "Unused namespace declarations take up space and require processing that is not " + 68 "necessary", 69 70 Category.CORRECTNESS, 71 1, 72 Severity.WARNING, 73 NamespaceDetector.class, 74 Scope.RESOURCE_FILE_SCOPE); 75 76 /** Using custom namespace attributes in a library project */ 77 public static final Issue CUSTOMVIEW = Issue.create( 78 "LibraryCustomView", //$NON-NLS-1$ 79 "Flags custom attributes in libraries, which must use the res-auto-namespace instead", 80 81 "When using a custom view with custom attributes in a library project, the layout " + 82 "must use the special namespace " + AUTO_URI + " instead of a URI which includes " + 83 "the library project's own package. This will be used to automatically adjust the " + 84 "namespace of the attributes when the library resources are merged into the " + 85 "application project.", 86 Category.CORRECTNESS, 87 6, 88 Severity.ERROR, 89 NamespaceDetector.class, 90 Scope.RESOURCE_FILE_SCOPE); 91 92 /** Prefix relevant for custom namespaces */ 93 private static final String XMLNS_ANDROID = "xmlns:android"; //$NON-NLS-1$ 94 private static final String XMLNS_A = "xmlns:a"; //$NON-NLS-1$ 95 96 private Map<String, Attr> mUnusedNamespaces; 97 private boolean mCheckUnused; 98 private boolean mCheckCustomAttrs; 99 100 /** Constructs a new {@link NamespaceDetector} */ 101 public NamespaceDetector() { 102 } 103 104 @Override 105 public Speed getSpeed() { 106 return Speed.FAST; 107 } 108 109 @Override 110 public void visitDocument(XmlContext context, Document document) { 111 boolean haveCustomNamespace = false; 112 Element root = document.getDocumentElement(); 113 NamedNodeMap attributes = root.getAttributes(); 114 for (int i = 0, n = attributes.getLength(); i < n; i++) { 115 Node item = attributes.item(i); 116 if (item.getNodeName().startsWith(XMLNS_PREFIX)) { 117 String value = item.getNodeValue(); 118 119 if (!value.equals(ANDROID_URI)) { 120 Attr attribute = (Attr) item; 121 122 if (value.startsWith(URI_PREFIX)) { 123 haveCustomNamespace = true; 124 if (mUnusedNamespaces == null) { 125 mUnusedNamespaces = new HashMap<String, Attr>(); 126 } 127 mUnusedNamespaces.put(item.getNodeName().substring(XMLNS_PREFIX.length()), 128 attribute); 129 } 130 131 String name = attribute.getName(); 132 if (!name.equals(XMLNS_ANDROID) && !name.equals(XMLNS_A)) { 133 continue; 134 } 135 136 if (!context.isEnabled(TYPO)) { 137 continue; 138 } 139 140 if (name.equals(XMLNS_A)) { 141 // For the "android" prefix we always assume that the namespace prefix 142 // should be our expected prefix, but for the "a" prefix we make sure 143 // that it's at least "close"; if you're bound it to something completely 144 // different, don't complain. 145 if (LintUtils.editDistance(ANDROID_URI, value) > 4) { 146 continue; 147 } 148 } 149 150 if (value.equalsIgnoreCase(ANDROID_URI)) { 151 context.report(TYPO, attribute, context.getLocation(attribute), 152 String.format( 153 "URI is case sensitive: was \"%1$s\", expected \"%2$s\"", 154 value, ANDROID_URI), null); 155 } else { 156 context.report(TYPO, attribute, context.getLocation(attribute), 157 String.format( 158 "Unexpected namespace URI bound to the \"android\" " + 159 "prefix, was %1$s, expected %2$s", value, ANDROID_URI), 160 null); 161 } 162 } 163 } 164 } 165 166 if (haveCustomNamespace) { 167 mCheckCustomAttrs = context.isEnabled(CUSTOMVIEW) && context.getProject().isLibrary(); 168 mCheckUnused = context.isEnabled(UNUSED); 169 checkElement(context, document.getDocumentElement()); 170 171 if (mCheckUnused && mUnusedNamespaces.size() > 0) { 172 for (Map.Entry<String, Attr> entry : mUnusedNamespaces.entrySet()) { 173 String prefix = entry.getKey(); 174 Attr attribute = entry.getValue(); 175 context.report(UNUSED, attribute, context.getLocation(attribute), 176 String.format("Unused namespace %1$s", prefix), null); 177 } 178 } 179 } 180 } 181 182 private void checkElement(XmlContext context, Node node) { 183 if (node.getNodeType() == Node.ELEMENT_NODE) { 184 if (mCheckCustomAttrs) { 185 String tag = node.getNodeName(); 186 if (tag.indexOf('.') != -1 187 // Don't consider android.support.* and android.app.FragmentBreadCrumbs etc 188 && !tag.startsWith(ANDROID_PKG_PREFIX)) { 189 NamedNodeMap attributes = ((Element) node).getAttributes(); 190 for (int i = 0, n = attributes.getLength(); i < n; i++) { 191 Attr attribute = (Attr) attributes.item(i); 192 String uri = attribute.getNamespaceURI(); 193 if (uri != null && uri.length() > 0 && uri.startsWith(URI_PREFIX) 194 && !uri.equals(ANDROID_URI)) { 195 context.report(CUSTOMVIEW, attribute, context.getLocation(attribute), 196 "When using a custom namespace attribute in a library project, " + 197 "use the namespace \"" + AUTO_URI + "\" instead.", null); 198 } 199 } 200 } 201 } 202 203 if (mCheckUnused) { 204 NamedNodeMap attributes = ((Element) node).getAttributes(); 205 for (int i = 0, n = attributes.getLength(); i < n; i++) { 206 Attr attribute = (Attr) attributes.item(i); 207 String prefix = attribute.getPrefix(); 208 if (prefix != null) { 209 mUnusedNamespaces.remove(prefix); 210 } 211 } 212 } 213 214 NodeList childNodes = node.getChildNodes(); 215 for (int i = 0, n = childNodes.getLength(); i < n; i++) { 216 checkElement(context, childNodes.item(i)); 217 } 218 } 219 } 220 } 221
