Preliminary attachments support

Added a partial Filespec support
Added getAttachments in API
Added a new attachments view in UI (with a new icon by @shorlander)

src/core/obj.js

@@ -454,6 +454,30 @@ var Catalog = (function CatalogClosure() {
       }
       return shadow(this, 'destinations', dests);
     },
+    get attachments() {
+      var xref = this.xref;
+      var attachments, nameTreeRef;
+      var obj = this.catDict.get('Names');
+      if (obj) {
+        nameTreeRef = obj.getRaw('EmbeddedFiles');
+      }
+
+      if (nameTreeRef) {
+        var nameTree = new NameTree(nameTreeRef, xref);
+        var names = nameTree.getAll();
+        for (var name in names) {
+          if (!names.hasOwnProperty(name)) {
+            continue;
+          }
+          var fs = new FileSpec(names[name], xref);
+          if (!attachments) {
+            attachments = {};
+          }
+          attachments[stringToPDFString(name)] = fs.serializable;
+        }
+      }
+      return shadow(this, 'attachments', attachments);
+    },
     get javaScript() {
       var xref = this.xref;
       var obj = this.catDict.get('Names');
@@ -1315,6 +1339,97 @@ var NameTree = (function NameTreeClosure() {
   return NameTree;
 })();
 
+/**
+ * "A PDF file can refer to the contents of another file by using a File 
+ * Specification (PDF 1.1)", see the spec (7.11) for more details.
+ * NOTE: Only embedded files are supported (as part of the attachments support)
+ * TODO: support the 'URL' file system (with caching if !/V), portable 
+ * collections attributes and related files (/RF)
+ */
+var FileSpec = (function FileSpecClosure() {
+  function FileSpec(root, xref) {
+    if (!root || !isDict(root)) {
+      return;
+    }
+    this.xref = xref;
+    this.root = root;
+    if (root.has('FS')) {
+      this.fs = root.get('FS');
+    }
+    this.description = root.has('Desc') ?
+                         stringToPDFString(root.get('Desc')) :
+                         '';
+    if (root.has('RF')) {
+      warn('Related file specifications are not supported');
+    }
+    this.contentAvailable = true;
+    if (!root.has('EF')) {
+      this.contentAvailable = false;
+      warn('Non-embedded file specifications are not supported');
+    }
+  }
+
+  function pickPlatformItem(dict) {
+    // Look for the filename in this order:
+    // UF, F, Unix, Mac, DOS
+    if (dict.has('UF')) {
+      return dict.get('UF');
+    } else if (dict.has('F')) {
+      return dict.get('F');
+    } else if (dict.has('Unix')) {
+      return dict.get('Unix');
+    } else if (dict.has('Mac')) {
+      return dict.get('Mac');
+    } else if (dict.has('DOS')) {
+      return dict.get('DOS');
+    } else {
+      return null;
+    }
+  }
+
+  FileSpec.prototype = {
+    get filename() {
+      if (!this._filename && this.root) {
+        var filename = pickPlatformItem(this.root) || 'unnamed';
+        this._filename = stringToPDFString(filename).
+          replace(/\\\\/g, '\\').
+          replace(/\\\//g, '/').
+          replace(/\\/g, '/');
+      }
+      return this._filename;
+    },
+    get content() {
+      if (!this.contentAvailable) {
+        return null;
+      }
+      if (!this.contentRef && this.root) {
+        this.contentRef = pickPlatformItem(this.root.get('EF'));
+      }
+      var content = null;
+      if (this.contentRef) {
+        var xref = this.xref;
+        var fileObj = xref.fetchIfRef(this.contentRef);
+        if (fileObj && isStream(fileObj)) {
+          content = fileObj.getBytes();
+        } else {
+          warn('Embedded file specification points to non-existing/invalid ' +
+            'content');
+        }
+      } else {
+        warn('Embedded file specification does not have a content');
+      }
+      return content;
+    },
+    get serializable() {
+      return {
+        filename: this.filename,
+        content: this.content
+      };
+    }
+  };
+  return FileSpec;
+})();
+
 /**
  * A helper for loading missing data in object graphs. It traverses the graph
  * depth first and queues up any objects that have missing data. Once it has