Add HTML rule and hint+fix for missing alt attribute for tag img, applet and area

ide/csl.api/test/unit/src/org/netbeans/modules/csl/api/test/CslTestBase.java

@@ -4358,8 +4358,11 @@ protected ComputedHints computeHints(final NbTestCase test, final Rule hint, Str
                             }
                         }
                         if (HintsSettings.getSeverity(manager, ucr) == HintSeverity.CURRENT_LINE_WARNING) {
-                            manager.setTestingRules(null, Collections.EMPTY_MAP, testHints, null);
+                            manager.setTestingRules(null, testHints, testHints, null);
                             provider.computeSuggestions(manager, context, hints, caretOffset);
+                        } else if(HintsSettings.getSeverity(manager, ucr) == HintSeverity.ERROR || HintsSettings.getSeverity(manager, ucr) == HintSeverity.WARNING) {
+                            manager.setTestingRules(null, testHints, testHints, null);
+                            provider.computeErrors(manager, context, hints, new ArrayList<Error>());
                         } else {
                             manager.setTestingRules(null, testHints, null, null);
                             context.caretOffset = -1;

ide/html.editor/src/org/netbeans/modules/html/editor/hints/Bundle.properties

@@ -106,4 +106,7 @@ MSG_SET_DEFAULT_HTML_VERSION=Change project default to {0}
 MSG_FatalHtmlRuleName=Fatal Errors
 MSG_FatalHtmlErrorAddendum=Further processing of the file may be significantly affected by this fatal error. Please fix the problem before continuing editing of this file!
 
+AddMissingAltAttributeRule=Provide Text Alternatives
+AddMissingAltAttributeRule_Desc=Find img/applet/area elements where no alt attribute is provided.
+
 #MSG_HINT_GENERATE_REQUIRED_ATTRIBUTES=Generate required attributes

ide/html.editor/src/org/netbeans/modules/html/editor/hints/other/AddMissingAltAttributeHint.java

@@ -0,0 +1,107 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you 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.netbeans.modules.html.editor.hints.other;
+
+import java.awt.EventQueue;
+import java.util.Collections;
+import java.util.logging.Level;
+import java.util.logging.Logger;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+import javax.swing.text.BadLocationException;
+import javax.swing.text.Document;
+import org.netbeans.editor.BaseDocument;
+import org.netbeans.modules.csl.api.Hint;
+import org.netbeans.modules.csl.api.HintFix;
+import org.netbeans.modules.csl.api.OffsetRange;
+import org.netbeans.modules.html.editor.hints.HtmlRuleContext;
+import org.netbeans.modules.html.editor.utils.HtmlTagContextUtils;
+import org.netbeans.modules.parsing.api.Source;
+
+/**
+ *
+ * @author Christian Lenz
+ */
+public class AddMissingAltAttributeHint extends Hint {
+
+    public AddMissingAltAttributeHint(HtmlRuleContext context, OffsetRange range) {
+        super(AddMissingAltAttributeRule.getInstance(),
+            AddMissingAltAttributeRule.getInstance().getDescription(),
+            context.getFile(),
+            range,
+            Collections.<HintFix>singletonList(new AddMissingAltAttributeHintFix(context, range)),
+            10);
+    }
+
+    private static class AddMissingAltAttributeHintFix implements HintFix {
+
+        private static final Logger LOGGER = Logger.getLogger(AddMissingAltAttributeHintFix.class.getSimpleName());
+
+        HtmlRuleContext context;
+        OffsetRange range;
+
+        public AddMissingAltAttributeHintFix(HtmlRuleContext context, OffsetRange range) {
+            this.context = context;
+            this.range = range;
+        }
+
+        @Override
+        public String getDescription() {
+            return AddMissingAltAttributeRule.getInstance().getDisplayName();
+        }
+
+        @Override
+        public void implement() throws Exception {
+            BaseDocument document = (BaseDocument) context.getSnapshot().getSource().getDocument(true);
+            document.runAtomic(() -> {
+                try {
+                    OffsetRange adjustedRange = HtmlTagContextUtils.adjustContextRange(document, range.getStart(), range.getEnd(), true);
+                    String tagContent = document.getText(adjustedRange.getStart(), adjustedRange.getLength());
+
+                    // Find last self-closing or non self-closing tag
+                    Pattern closingTagPattern = Pattern.compile("(/?>)");
+                    Matcher closingTagMatcher = closingTagPattern.matcher(tagContent);
+
+                    if (closingTagMatcher.find()) {
+                        int altInsertPosition = adjustedRange.getStart() + closingTagMatcher.start(1);
+
+                        // Check whether a space before alt is needed or not
+                        boolean needsSpaceBefore = altInsertPosition == 0 || tagContent.charAt(closingTagMatcher.start(1) - 1) != ' ';
+                        boolean isSelfClosing = closingTagMatcher.group(0).endsWith("/>");
+                        String altAttribute = (needsSpaceBefore ? " " : "") + "alt=\"\"" + (isSelfClosing ? " " : ""); // NOI18N
+
+                        document.insertString(altInsertPosition, altAttribute, null);
+                    }
+                } catch (BadLocationException ex) {
+                    LOGGER.log(Level.WARNING, "Invalid offset: {0}", ex.offsetRequested());
+                }
+            });
+        }
+
+        @Override
+        public boolean isSafe() {
+            return true;
+        }
+
+        @Override
+        public boolean isInteractive() {
+            return false;
+        }
+    }
+}

ide/html.editor/src/org/netbeans/modules/html/editor/hints/other/AddMissingAltAttributeRule.java

@@ -0,0 +1,74 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you 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.netbeans.modules.html.editor.hints.other;
+
+import java.io.IOException;
+import java.util.List;
+import org.netbeans.modules.csl.api.Hint;
+import org.netbeans.modules.csl.api.HintSeverity;
+import org.netbeans.modules.csl.api.RuleContext;
+import org.netbeans.modules.html.editor.api.gsf.HtmlParserResult;
+import org.netbeans.modules.html.editor.hints.HtmlRule;
+import org.netbeans.modules.html.editor.hints.HtmlRuleContext;
+import org.netbeans.modules.html.editor.lib.api.elements.ElementType;
+import org.netbeans.modules.html.editor.lib.api.elements.ElementUtils;
+import org.openide.util.Exceptions;
+
+/**
+ *
+ * @author Christian Lenz
+ */
+public class AddMissingAltAttributeRule extends HtmlRule {
+
+    private final static AddMissingAltAttributeRule INSTANCE = new AddMissingAltAttributeRule();
+
+    private AddMissingAltAttributeRule() {
+    }
+
+    public static AddMissingAltAttributeRule getInstance() {
+        return INSTANCE;
+    }
+
+    @Override
+    public boolean appliesTo(RuleContext context) {
+        return true;
+    }
+
+    @Override
+    public boolean showInTasklist() {
+        return true;
+    }
+
+    @Override
+    public HintSeverity getDefaultSeverity() {
+        return HintSeverity.CURRENT_LINE_WARNING;
+    }
+
+    @Override
+    protected void run(HtmlRuleContext context, List<Hint> result) {
+        try {
+            HtmlParserResult parserResult = context.getHtmlParserResult();
+            AltAttributeVisitor visitor = new AltAttributeVisitor(this, context, result);
+
+            ElementUtils.visitChildren(parserResult.root(), visitor, ElementType.OPEN_TAG);
+        } catch (IOException ioe) {
+            Exceptions.printStackTrace(ioe);
+        }
+    }
+}

ide/html.editor/src/org/netbeans/modules/html/editor/hints/other/AltAttributeVisitor.java

@@ -0,0 +1,63 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you 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.netbeans.modules.html.editor.hints.other;
+
+import java.io.IOException;
+import java.util.*;
+import org.netbeans.modules.csl.api.Hint;
+import org.netbeans.modules.csl.api.OffsetRange;
+import org.netbeans.modules.csl.api.Rule;
+import org.netbeans.modules.html.editor.hints.HtmlRuleContext;
+import org.netbeans.modules.html.editor.lib.api.elements.*;
+
+/**
+ *
+ * @author Christian Lenz
+ */
+public class AltAttributeVisitor implements ElementVisitor {
+
+    private static final String ALT_ATTR = "alt"; // NOI18N
+
+    private final HtmlRuleContext context;
+    private final List<Hint> hints;
+
+    public AltAttributeVisitor(Rule rule, HtmlRuleContext context, List<Hint> hints) throws IOException {
+        this.context = context;
+        this.hints = hints;
+    }
+
+    @Override
+    public void visit(Element node) {
+        // We should only be invoked for opening tags
+        if (!(node instanceof OpenTag)) {
+            return;
+        }
+
+        // We are only interested in img, area, applet elements
+        String lowerCaseTag = node.id().toString().toLowerCase();
+        if (!(lowerCaseTag.equals("img") || lowerCaseTag.equals("area") || lowerCaseTag.equals("applet"))) { // NOI18N
+            return;
+        }
+
+        OpenTag ot = (OpenTag) node;
+        if (ot.getAttribute(ALT_ATTR) == null) {
+            hints.add(new AddMissingAltAttributeHint(context, new OffsetRange(node.from(), node.to())));
+        }
+    }
+}

ide/html.editor/src/org/netbeans/modules/html/editor/resources/layer.xml

@@ -534,6 +534,9 @@
                         <file name="org-netbeans-modules-html-editor-hints-NotValidatedContent.instance">
                             <attr name="position" intvalue="190"/>                            
                         </file>
+                        <file name="org-netbeans-modules-html-editor-hints-other-AddMissingAltAttributeRule.instance">
+                            <attr name="position" intvalue="210"/>                            
+                        </file>
                         <!-- the following hint 'Other' must be last in the hints list!!! -->
                         <file name="org-netbeans-modules-html-editor-hints-Other.instance">
                             <attr name="position" intvalue="99999"/>                            

ide/html.editor/src/org/netbeans/modules/html/editor/utils/HtmlTagContextUtils.java

@@ -0,0 +1,88 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you 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.netbeans.modules.html.editor.utils;
+
+import java.util.concurrent.atomic.AtomicReference;
+import javax.swing.text.Document;
+import org.netbeans.api.html.lexer.HTMLTokenId;
+import org.netbeans.api.lexer.Token;
+import org.netbeans.api.lexer.TokenSequence;
+import org.netbeans.modules.csl.api.OffsetRange;
+import org.netbeans.modules.html.editor.api.Utils;
+
+/**
+ *
+ * @author Christian Lenz
+ */
+public final class HtmlTagContextUtils {
+
+    private HtmlTagContextUtils() {
+    }
+
+    public static OffsetRange adjustContextRange(final Document doc, final int from, final int to, final boolean beforeClosingToken) {
+        final AtomicReference<OffsetRange> ret = new AtomicReference<>();
+        ret.set(new OffsetRange(from, to)); //return the same pair by default
+        doc.render(() -> {
+            TokenSequence<HTMLTokenId> ts = Utils.getJoinedHtmlSequence(doc, from);
+
+            if (ts == null) {
+                //no html token sequence at the offset, try to
+                //TODO possibly try to travese the top level sequence backward
+                //and try to find an html embedding.
+                return;
+            }
+
+            Token<HTMLTokenId> openTag = Utils.findTagOpenToken(ts);
+
+            if (openTag == null) {
+                return;
+            }
+
+            int adjustedFrom = ts.offset();
+
+            //now try to find the tag's end
+            ts.move(to);
+            int adjustedTo = -1;
+            while (ts.moveNext()) {
+                Token<HTMLTokenId> t = ts.token();
+
+                if (t == null) {
+                    return;
+                }
+
+                if (t.id() == HTMLTokenId.TAG_CLOSE_SYMBOL) {
+                    adjustedTo = beforeClosingToken ? ts.offset() : ts.offset() + t.length();
+
+                    break;
+                } else if (t.id() == HTMLTokenId.TEXT) {
+                    //do not go too far - out of the tag
+                    break;
+                }
+            }
+
+            if (adjustedTo == -1) {
+                return;
+            }
+
+            //we found the adjusted range
+            ret.set(new OffsetRange(adjustedFrom, adjustedTo));
+        });
+        return ret.get();
+    }
+}