Detect removed files and reflect the state in chrome://downloads and the download shelf

chrome/browser/download/download_manager.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/download/download_manager.h"
 
 #include "base/callback.h"
 #include "base/file_util.h"
 #include "base/i18n/case_conversion.h"
 #include "base/logging.h"
@@ skipping 256 matching lines @@
     return;
 
   // Create a client to verify download URL with safebrowsing.
   // It deletes itself after the callback.
   scoped_refptr<DownloadSBClient> sb_client = new DownloadSBClient(
       download_id, download->url_chain(), download->referrer_url());
   sb_client->CheckDownloadUrl(
       NewCallback(this, &DownloadManager::CheckDownloadUrlDone));
 }
 
+void DownloadManager::CheckForHistoryFilesRemoval() {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+  for (DownloadMap::iterator it = history_downloads_.begin();
+       it != history_downloads_.end(); ++it) {
+    CheckForFileRemoval(it->second);
+  }
+}
+
+void DownloadManager::CheckForFileRemoval(DownloadItem* download_item) {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+  if (download_item->IsComplete() &&
+      !download_item->file_externally_removed()) {
+    BrowserThread::PostTask(
+        BrowserThread::FILE, FROM_HERE,
+        NewRunnableMethod(this,
+                          &DownloadManager::CheckForFileRemovalOnFileThread,
+                          download_item->db_handle(),
+                          download_item->GetTargetFilePath()));
+  }
+}
+
+void DownloadManager::CheckForFileRemovalOnFileThread(
+    int64 db_handle, const FilePath& path) {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::FILE));
+  if (!file_util::PathExists(path)) {
+    BrowserThread::PostTask(
+        BrowserThread::UI, FROM_HERE,
+        NewRunnableMethod(this,
+                          &DownloadManager::OnFileRemovalDetected,
+                          db_handle));
+  }
+}
+
+void DownloadManager::OnFileRemovalDetected(int64 db_handle) {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+  DownloadMap::iterator it = history_downloads_.find(db_handle);
+  if (it != history_downloads_.end()) {
+    DownloadItem* download_item = it->second;
+    download_item->OnDownloadedFileRemoved();
+  }
+}
+
 void DownloadManager::CheckDownloadUrlDone(int32 download_id,
                                            bool is_dangerous_url) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
 
   DownloadItem* download = GetActiveDownloadItem(download_id);
   if (!download)
     return;
 
   if (is_dangerous_url)
     download->MarkUrlDangerous();
@@ skipping 791 matching lines @@
     std::vector<DownloadHistoryInfo>* entries) {
   for (size_t i = 0; i < entries->size(); ++i) {
     DownloadItem* download = new DownloadItem(this, entries->at(i));
     DCHECK(!ContainsKey(history_downloads_, download->db_handle()));
     downloads_.insert(download);
     history_downloads_[download->db_handle()] = download;
     VLOG(20) << __FUNCTION__ << "()" << i << ">"
              << " download = " << download->DebugString(true);
   }
   NotifyModelChanged();
+  CheckForHistoryFilesRemoval();
 }
 
 // Once the new DownloadItem's creation info has been committed to the history
 // service, we associate the DownloadItem with the db handle, update our
 // 'history_downloads_' map and inform observers.
 void DownloadManager::OnCreateDownloadEntryComplete(int32 download_id,
                                                     int64 db_handle) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
   DownloadItem* download = GetActiveDownloadItem(download_id);
   if (!download)
@@ skipping 163 matching lines @@
     observed_download_manager_->RemoveObserver(this);
 }
 
 void DownloadManager::OtherDownloadManagerObserver::ModelChanged() {
   observing_download_manager_->NotifyModelChanged();
 }
 
 void DownloadManager::OtherDownloadManagerObserver::ManagerGoingDown() {
   observed_download_manager_ = NULL;
 }