[api-minor] Add support for URLs in the document outline

Re: issue 5089.
(Note that since there are other outline features that we currently don't support, e.g. bold/italic text and custom colours, I thus think we can keep the referenced issue open.)

src/core/obj.js

@@ -47,6 +47,7 @@ var shadow = sharedUtil.shadow;
 var stringToPDFString = sharedUtil.stringToPDFString;
 var stringToUTF8String = sharedUtil.stringToUTF8String;
 var warn = sharedUtil.warn;
+var isValidUrl = sharedUtil.isValidUrl;
 var Ref = corePrimitives.Ref;
 var RefSet = corePrimitives.RefSet;
 var RefSetCache = corePrimitives.RefSetCache;
@@ -146,9 +147,17 @@ var Catalog = (function CatalogClosure() {
             if (!outlineDict.has('Title')) {
               error('Invalid outline item');
             }
-            var dest = outlineDict.get('A');
-            if (dest) {
-              dest = dest.get('D');
+            var actionDict = outlineDict.get('A'), dest = null, url = null;
+            if (actionDict) {
+              var destEntry = actionDict.get('D');
+              if (destEntry) {
+                dest = destEntry;
+              } else {
+                var uriEntry = actionDict.get('URI');
+                if (isString(uriEntry) && isValidUrl(uriEntry, false)) {
+                  url = uriEntry;
+                }
+              }
             } else if (outlineDict.has('Dest')) {
               dest = outlineDict.getRaw('Dest');
               if (isName(dest)) {
@@ -158,6 +167,7 @@ var Catalog = (function CatalogClosure() {
             var title = outlineDict.get('Title');
             var outlineItem = {
               dest: dest,
+              url: url,
               title: stringToPDFString(title),
               color: outlineDict.get('C') || [0, 0, 0],
               count: outlineDict.get('Count'),

src/display/annotation_layer.js

@@ -31,9 +31,7 @@
 var AnnotationBorderStyleType = sharedUtil.AnnotationBorderStyleType;
 var AnnotationType = sharedUtil.AnnotationType;
 var Util = sharedUtil.Util;
-var isExternalLinkTargetSet = sharedUtil.isExternalLinkTargetSet;
-var LinkTargetStringMap = sharedUtil.LinkTargetStringMap;
-var removeNullCharacters = sharedUtil.removeNullCharacters;
+var addLinkAttributes = sharedUtil.addLinkAttributes;
 var warn = sharedUtil.warn;
 var CustomStyle = displayDOMUtils.CustomStyle;
 
@@ -233,17 +231,7 @@ var LinkAnnotationElement = (function LinkAnnotationElementClosure() {
       this.container.className = 'linkAnnotation';
 
       var link = document.createElement('a');
-      link.href = link.title = (this.data.url ?
-                                removeNullCharacters(this.data.url) : '');
-
-      if (this.data.url && isExternalLinkTargetSet()) {
-        link.target = LinkTargetStringMap[PDFJS.externalLinkTarget];
-      }
-
-      // Strip referrer from the URL.
-      if (this.data.url) {
-        link.rel = PDFJS.externalLinkRel;
-      }
+      addLinkAttributes(link, { url: this.data.url });
 
       if (!this.data.url) {
         if (this.data.action) {

src/display/api.js

@@ -714,6 +714,7 @@ var PDFDocumentProxy = (function PDFDocumentProxyClosure() {
      *   italic: boolean,
      *   color: rgb array,
      *   dest: dest obj,
+     *   url: string,
      *   items: array of more items like this
      *  },
      *  ...

src/shared/util.js

@@ -318,6 +318,26 @@ function isValidUrl(url, allowRelative) {
 }
 PDFJS.isValidUrl = isValidUrl;
 
+/**
+ * Adds various attributes (href, title, target, rel) to hyperlinks.
+ * @param {HTMLLinkElement} link - The link element.
+ * @param {Object} params - An object with the properties:
+ * @param {string} params.url - An absolute URL.
+ */
+function addLinkAttributes(link, params) {
+  var url = params && params.url;
+  link.href = link.title = (url ? removeNullCharacters(url) : '');
+
+  if (url) {
+    if (isExternalLinkTargetSet()) {
+      link.target = LinkTargetStringMap[PDFJS.externalLinkTarget];
+    }
+    // Strip referrer from the URL.
+    link.rel = PDFJS.externalLinkRel;
+  }
+}
+PDFJS.addLinkAttributes = addLinkAttributes;
+
 function shadow(obj, prop, value) {
   Object.defineProperty(obj, prop, { value: value,
                                      enumerable: true,
@@ -2292,6 +2312,7 @@ exports.isInt = isInt;
 exports.isNum = isNum;
 exports.isString = isString;
 exports.isValidUrl = isValidUrl;
+exports.addLinkAttributes = addLinkAttributes;
 exports.loadJpegStream = loadJpegStream;
 exports.log2 = log2;
 exports.readInt8 = readInt8;