Implement chrome.experimental.downloads.search()

content/browser/download/download_manager.h

 // 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.
 //
 // The DownloadManager object manages the process of downloading, including
 // updates to the history system and providing the information for displaying
 // the downloads view in the Destinations tab. There is one DownloadManager per
 // active browser context in Chrome.
 //
 // Download observers:
@@ skipping 28 matching lines @@
 #include "base/gtest_prod_util.h"
 #include "base/hash_tables.h"
 #include "base/memory/ref_counted.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/memory/weak_ptr.h"
 #include "base/observer_list.h"
 #include "base/synchronization/lock.h"
 #include "base/time.h"
 #include "content/browser/browser_thread.h"
 #include "content/browser/download/download_item.h"
+#include "content/browser/download/download_query.h"
 #include "content/browser/download/download_request_handle.h"
 #include "content/browser/download/download_status_updater_delegate.h"
 #include "content/common/content_export.h"
 #include "net/base/net_errors.h"
 
 class DownloadFileManager;
 class DownloadManagerDelegate;
 class DownloadStatusUpdater;
 class GURL;
 class ResourceDispatcherHost;
@@ skipping 40 matching lines @@
 
   typedef std::vector<DownloadItem*> DownloadVector;
 
   // Return all temporary downloads that reside in the specified directory.
   void GetTemporaryDownloads(const FilePath& dir_path, DownloadVector* result);
 
   // Return all non-temporary downloads in the specified directory that are
   // are in progress or have completed.
   void GetAllDownloads(const FilePath& dir_path, DownloadVector* result);
 
+  // If |results| or |json_results| is non-NULL, fill it/them with DownloadItems
+  // matching |query|. If |error_msg| is non-NULL, set it to an error message if
+  // |query| was mal-formed.

[Randy Smith (Not in Mondays), 2011/10/10 18:09:42]

This interface makes me uncomfortable for two reasons: a) Having two output
vectors seems like overkill; I'd rather have the lower level (C++) one and then
translate it into json if needed, and b) returning a string error message at the
DownloadManager level feels wrong--I'd rather return an error code, and
translate it when we know we're actually sending the error message to the user. 

Looking at the current code, it doesn't look like there's a real performance
cost to fixing (a)--we do the translation inline now, but we could do it with a
second scan, and the cost of translating an element to json is going to much
higher than that of a single ++ in a DownloadVector.

[benjhayden, 2011/10/13 14:07:34]

Done.

+  bool Search(const download_util::DownloadQuery& query,
+              std::string* error_msg,
+              DownloadVector* results,
+              base::ListValue* json_results) const;
+
   // Returns all non-temporary downloads matching |query|. Empty query matches
   // everything.
   void SearchDownloads(const string16& query, DownloadVector* result);
 
   // Returns the next download id in a DownloadId and increments the counter.
   // May be called on any thread. The incremented counter is not persisted, but
   // the base counter for this accessor is initialized from the largest id
   // actually saved to the download history database.
   DownloadId GetNextId();
 
@@ skipping 308 matching lines @@
   DownloadManagerDelegate* delegate_;
 
   // TODO(rdsmith): Remove when http://crbug.com/84508 is fixed.
   // For debugging only.
   int64 largest_db_handle_in_history_;
 
   DISALLOW_COPY_AND_ASSIGN(DownloadManager);
 };
 
 #endif  // CONTENT_BROWSER_DOWNLOAD_DOWNLOAD_MANAGER_H_