Allow empty strings to be written to the clipboard

webkit/glue/webdropdata.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "webkit/glue/webdropdata.h"
 
 #include <utility>
 
 #include "base/string_util.h"
 #include "base/logging.h"
@@ skipping 13 matching lines @@
 WebDropData::FileInfo::FileInfo() {
 }
 
 WebDropData::FileInfo::FileInfo(const string16& path,
                                 const string16& display_name)
     : path(path),
       display_name(display_name) {
 }
 
 WebDropData::WebDropData(const WebDragData& drag_data)
-    : referrer_policy(WebKit::WebReferrerPolicyDefault) {
+    : referrer_policy(WebKit::WebReferrerPolicyDefault),
+      text(NullableString16(true)),
+      html(NullableString16(true)) {
   const WebVector<WebDragData::Item>& item_list = drag_data.items();
   for (size_t i = 0; i < item_list.size(); ++i) {
     const WebDragData::Item& item = item_list[i];
     switch (item.storageType) {
       case WebDragData::Item::StorageTypeString: {
         if (EqualsASCII(item.stringType, ui::Clipboard::kMimeTypeText)) {
-          plain_text = item.stringData;
+          text = NullableString16(item.stringData, false);
           break;
         }
         if (EqualsASCII(item.stringType, ui::Clipboard::kMimeTypeURIList)) {
           url = GURL(item.stringData);
           url_title = item.title;
           break;
         }
         if (EqualsASCII(item.stringType, ui::Clipboard::kMimeTypeDownloadURL)) {
           download_metadata = item.stringData;
           break;
         }
         if (EqualsASCII(item.stringType, ui::Clipboard::kMimeTypeHTML)) {
-          text_html = item.stringData;
+          html = NullableString16(item.stringData, false);
           html_base_url = item.baseURL;
           break;
         }
         custom_data.insert(std::make_pair(item.stringType, item.stringData));
         break;
       }
       case WebDragData::Item::StorageTypeBinaryData:
         file_contents.assign(item.binaryData.data(),
                              item.binaryData.size());
         file_description_filename = item.title;
         break;
       case WebDragData::Item::StorageTypeFilename:
         // TODO(varunjain): This only works on chromeos. Support win/mac/gtk.
         filenames.push_back(FileInfo(item.filenameData,
                                      item.displayNameData));
         break;
     }
   }
 }
 
 WebDropData::WebDropData()
-    : referrer_policy(WebKit::WebReferrerPolicyDefault) {
+    : referrer_policy(WebKit::WebReferrerPolicyDefault),
+      text(NullableString16(true)),
+      html(NullableString16(true)) {
 }
 
 WebDropData::~WebDropData() {
 }
 
 WebDragData WebDropData::ToDragData() const {
   std::vector<WebDragData::Item> item_list;
 
   // These fields are currently unused when dragging into WebKit.
   DCHECK(download_metadata.empty());
   DCHECK(file_contents.empty());
   DCHECK(file_description_filename.empty());
 
-  // TODO(dcheng): We need a way to distinguish between null and empty strings.
-  if (!plain_text.empty()) {
+  if (!text.is_null()) {
     WebDragData::Item item;
     item.storageType = WebDragData::Item::StorageTypeString;
     item.stringType = WebString::fromUTF8(ui::Clipboard::kMimeTypeText);
-    item.stringData = plain_text;
+    item.stringData = text.string();
     item_list.push_back(item);
   }
 
+  // TODO(dcheng): Do we need to distinguish between null and empty URLs? Is it
+  // meaningful to write an empty URL to the clipboard?
   if (!url.is_empty()) {
     WebDragData::Item item;
     item.storageType = WebDragData::Item::StorageTypeString;
     item.stringType = WebString::fromUTF8(ui::Clipboard::kMimeTypeURIList);
     item.stringData = WebString::fromUTF8(url.spec());
     item.title = url_title;
     item_list.push_back(item);
   }
 
-  if (!text_html.empty()) {
+  if (!html.is_null()) {
     WebDragData::Item item;
     item.storageType = WebDragData::Item::StorageTypeString;
     item.stringType = WebString::fromUTF8(ui::Clipboard::kMimeTypeHTML);
-    item.stringData = text_html;
+    item.stringData = html.string();
     item.baseURL = html_base_url;
     item_list.push_back(item);
   }
 
   for (std::vector<FileInfo>::const_iterator it =
            filenames.begin(); it != filenames.end(); ++it) {
     WebDragData::Item item;
     item.storageType = WebDragData::Item::StorageTypeFilename;
     item.filenameData = it->path;
     item.displayNameData = it->display_name;
     item_list.push_back(item);
   }
 
   for (std::map<string16, string16>::const_iterator it = custom_data.begin();
        it != custom_data.end();
        ++it) {
     WebDragData::Item item;
     item.storageType = WebDragData::Item::StorageTypeString;
     item.stringType = it->first;
     item.stringData = it->second;
     item_list.push_back(item);
   }
 
   WebDragData result;
   result.initialize();
   result.setItems(item_list);
   result.setFilesystemId(filesystem_id);
   return result;
 }