Implement chrome.experimental.downloads.onChanged

chrome/browser/extensions/extension_downloads_api.cc

 // Copyright (c) 2011 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 "chrome/browser/extensions/extension_downloads_api.h"
 
 #include <algorithm>
 #include <cctype>
 #include <iterator>
 #include <set>
@@ skipping 396 matching lines @@
   // TODO(benjhayden): Implement endTime and fileSize.
   // json->SetInteger(constants::kEndTimeKey, -1);
   json->SetInteger(constants::kFileSizeKey, item->total_bytes());
   return json;
 }
 }  // anonymous namespace
 
 ExtensionDownloadsEventRouter::ExtensionDownloadsEventRouter(
     Profile* profile)
   : profile_(profile),
-    manager_(profile ? profile->GetDownloadManager() : NULL) {
+    manager_(profile ? profile->GetDownloadManager() : NULL),
+    delete_item_jsons_(&item_jsons_) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
-  DCHECK(profile_);
-  DCHECK(manager_);
   manager_->AddObserver(this);
 }
 
 ExtensionDownloadsEventRouter::~ExtensionDownloadsEventRouter() {
   if (manager_ != NULL)
     manager_->RemoveObserver(this);
+  for (ItemMap::const_iterator iter = downloads_.begin();
+       iter != downloads_.end(); ++iter) {
+    iter->second->RemoveObserver(this);
+  }
+}
+
+void ExtensionDownloadsEventRouter::OnDownloadUpdated(DownloadItem* item) {
+  if (item->state() == DownloadItem::REMOVING)
+    return;

[Randy Smith (Not in Mondays), 2011/10/13 23:42:59]

I feel a bit uncomfortable about keeping a DownloadItem* pointer around after
getting a REMOVING notification.  I suspect that the code'll get rid of it in
the ModelChanged() event, but this notification is a specific request to let go
of any pointers to the item we might have, and I think it'll produce less
fragile code to do it here.

[benjhayden, 2011/10/17 19:14:00]

Done.

+  base::DictionaryValue* current_json = item_jsons_[item->id()];
+  scoped_ptr<base::DictionaryValue> new_json(DownloadItemToJSON(item));
+  scoped_ptr<base::DictionaryValue> delta(new base::DictionaryValue());
+  delta->SetInteger(constants::kIdKey, item->id());
+  bool changed = false;
+  for (base::DictionaryValue::key_iterator key = new_json->begin_keys();
+       key != new_json->end_keys(); ++key) {
+    if (*key != constants::kBytesReceivedKey) {
+      base::Value* new_value = NULL;
+      base::Value* old_value = NULL;
+      if (new_json->Get(*key, &new_value) &&
+          (!current_json->HasKey(*key) ||
+          (current_json->Get(*key, &old_value) &&
+            !new_value->Equals(old_value)))) {
+        delta->Set(*key + ".old", (old_value ? old_value->DeepCopy()
+                                            : base::Value::CreateNullValue()));
+        delta->Set(*key + ".new", new_value->DeepCopy());
+        changed = true;
+      }
+    }
+  }
+  if (changed)
+    DispatchEvent(extension_event_names::kOnDownloadChanged, delta.release());
+  current_json->Swap(new_json.get());
+}
+
+void ExtensionDownloadsEventRouter::OnDownloadOpened(DownloadItem* item) {
 }
 
 void ExtensionDownloadsEventRouter::ModelChanged() {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
   if (manager_ == NULL)
     return;
   DownloadManager::DownloadVector current_vec;
   manager_->SearchDownloads(string16(), &current_vec);
-  DownloadIdSet current_set;
+  DownloadIdSet current_set, prev_set;
+  for (ItemMap::const_iterator iter = downloads_.begin();
+       iter != downloads_.end(); ++iter) {
+    prev_set.insert(iter->first);
+  }
   ItemMap current_map;
   for (DownloadManager::DownloadVector::const_iterator iter =
        current_vec.begin();
        iter != current_vec.end(); ++iter) {
     DownloadItem* item = *iter;
     int item_id = item->id();
     // TODO(benjhayden): Remove the following line when every item's id >= 0,
     // which will allow firing onErased events for items from the history.
     if (item_id < 0) continue;
     DCHECK(current_map.find(item_id) == current_map.end());
     current_set.insert(item_id);
     current_map[item_id] = item;
   }
-  DownloadIdSet new_set;  // current_set - downloads_;
-  DownloadIdSet erased_set;  // downloads_ - current_set;
+  DownloadIdSet new_set;  // current_set - prev_set;
+  DownloadIdSet erased_set;  // prev_set - current_set;
   std::insert_iterator<DownloadIdSet> new_insertor(new_set, new_set.begin());
   std::insert_iterator<DownloadIdSet> erased_insertor(
       erased_set, erased_set.begin());
   std::set_difference(current_set.begin(), current_set.end(),
-                      downloads_.begin(), downloads_.end(),
+                      prev_set.begin(), prev_set.end(),
                       new_insertor);
-  std::set_difference(downloads_.begin(), downloads_.end(),
+  std::set_difference(prev_set.begin(), prev_set.end(),
                       current_set.begin(), current_set.end(),
                       erased_insertor);
   for (DownloadIdSet::const_iterator iter = new_set.begin();
        iter != new_set.end(); ++iter) {
     DispatchEvent(extension_event_names::kOnDownloadCreated,
                   DownloadItemToJSON(current_map[*iter]));
+    DCHECK(item_jsons_.find(*iter) == item_jsons_.end());
+    item_jsons_[*iter] = DownloadItemToJSON(current_map[*iter]);
+    current_map[*iter]->AddObserver(this);
   }
   for (DownloadIdSet::const_iterator iter = erased_set.begin();
        iter != erased_set.end(); ++iter) {
     DispatchEvent(extension_event_names::kOnDownloadErased,
                   base::Value::CreateIntegerValue(*iter));
+    delete item_jsons_[*iter];
+    item_jsons_.erase(*iter);
   }
-  downloads_.swap(current_set);
+  downloads_.swap(current_map);
 }
 
 void ExtensionDownloadsEventRouter::ManagerGoingDown() {
   manager_->RemoveObserver(this);
   manager_ = NULL;
 }
 
 void ExtensionDownloadsEventRouter::DispatchEvent(
     const char* event_name, base::Value* arg) {
   ListValue args;
   args.Append(arg);
   std::string json_args;
   base::JSONWriter::Write(&args, false, &json_args);
   profile_->GetExtensionEventRouter()->DispatchEventToRenderers(
       event_name,
       json_args,
       profile_,
       GURL());
 }