Fixed issue with DownloadTestObserver.

chrome/browser/download/download_test_observer.h

 // 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.
 
 #ifndef CHROME_BROWSER_DOWNLOAD_DOWNLOAD_TEST_OBSERVER_H_
 #define CHROME_BROWSER_DOWNLOAD_DOWNLOAD_TEST_OBSERVER_H_
 #pragma once
 
 #include <set>
 
 #include "base/basictypes.h"
 #include "base/memory/ref_counted.h"
 #include "content/public/browser/download_item.h"
 #include "content/public/browser/download_manager.h"
 
-// Construction of this class defines a system state, based on some number
-// of downloads being seen in a particular state + other events that
-// may occur in the download system.  That state will be recorded if it
-// occurs at any point after construction.  When that state occurs, the class
-// is considered finished.  Callers may either probe for the finished state, or
-// wait on it.
+// Detects changes to the downloads after construction.
+// Finishes when one of the following happens:
+//   - A specified number of downloads change to a terminal state (defined
+//     as anything but IN_PROGRESS).
+//   - Specific events, such as a select file dialog.
+// Callers may either probe for the finished state, or wait on it.
 //
 // TODO(rdsmith): Detect manager going down, remove pointer to
 // DownloadManager, transition to finished.  (For right now we
 // just use a scoped_refptr<> to keep it around, but that may cause
 // timeouts on waiting if a DownloadManager::Shutdown() occurs which
 // cancels our in-progress downloads.)
-class DownloadTestObserver : public content::DownloadManager::Observer,
-                             public content::DownloadItem::Observer {
+class DownloadTestObserverTerminal : public content::DownloadManager::Observer,
+                                     public content::DownloadItem::Observer {
  public:
   // Action an observer should take if a dangerous download is encountered.
   enum DangerousDownloadAction {
     ON_DANGEROUS_DOWNLOAD_ACCEPT,  // Accept the download
     ON_DANGEROUS_DOWNLOAD_DENY,  // Deny the download
     ON_DANGEROUS_DOWNLOAD_FAIL  // Fail if a dangerous download is seen
   };
 
   // Create an object that will be considered finished when |wait_count|
-  // download items have entered state |download_finished_state|.
+  // download items have entered a terminal state (either CANCELLED or
+  // another state that you can't normally transition out of).
   // If |finish_on_select_file| is true, the object will also be
   // considered finished if the DownloadManager raises a
   // SelectFileDialogDisplayed() notification.
-
-  // TODO(rdsmith): Consider rewriting the interface to take a list of events
-  // to treat as completion events.
-  DownloadTestObserver(
+  DownloadTestObserverTerminal(
       content::DownloadManager* download_manager,
       size_t wait_count,
-      content::DownloadItem::DownloadState download_finished_state,
       bool finish_on_select_file,
       DangerousDownloadAction dangerous_download_action);
 
-  virtual ~DownloadTestObserver();
+  virtual ~DownloadTestObserverTerminal();
 
   // State accessors.
   bool select_file_dialog_seen() const { return select_file_dialog_seen_; }
 
-  // Wait for whatever state was specified in the constructor.
+  // Wait for the requested number of downloads to enter a terminal state.
   void WaitForFinished();
 
   // Return true if everything's happened that we're configured for.
   bool IsFinished() const;
 
   // content::DownloadItem::Observer
   virtual void OnDownloadUpdated(content::DownloadItem* download) OVERRIDE;
   virtual void OnDownloadOpened(content::DownloadItem* download) OVERRIDE {}
 
   // content::DownloadManager::Observer
   virtual void ModelChanged(content::DownloadManager* manager) OVERRIDE;
 
   virtual void SelectFileDialogDisplayed(
       content::DownloadManager* manager, int32 id) OVERRIDE;
 
   size_t NumDangerousDownloadsSeen() const;
 
+ protected:
+  // Called to see if a download item is in a final state.
+  virtual bool IsDownloadInFinalState(content::DownloadItem* download);
+
  private:
   typedef std::set<content::DownloadItem*> DownloadSet;
 
   // Called when we know that a download item is in a final state.
   // Note that this is not the same as it first transitioning in to the
   // final state; multiple notifications may occur once the item is in
   // that state.  So we keep our own track of transitions into final.
   void DownloadInFinalState(content::DownloadItem* download);
 
   void SignalIfFinished();
@@ skipping 21 matching lines @@
   // construction and return from wait.  But some downloads may be in our
   // final state (and thus be entered into |finished_downloads_|) when we
   // construct this class.  We don't want to count those in our transition
   // to finished.
   int finished_downloads_at_construction_;
 
   // Whether an internal message loop has been started and must be quit upon
   // all downloads completing.
   bool waiting_;
 
-  // The state on which to consider the DownloadItem finished.
-  content::DownloadItem::DownloadState download_finished_state_;
-
-  // True if we should transition the DownloadTestObserver to finished if
-  // the select file dialog comes up.
+  // True if we should transition the DownloadTestObserverTerminal to
+  // finished if the select file dialog comes up.
   bool finish_on_select_file_;
 
   // True if we've seen the select file dialog.
   bool select_file_dialog_seen_;
 
   // Action to take if a dangerous download is encountered.
   DangerousDownloadAction dangerous_download_action_;
 
   // Holds the download ids which were dangerous.
   std::set<int32> dangerous_downloads_seen_;
 
-  DISALLOW_COPY_AND_ASSIGN(DownloadTestObserver);
+  DISALLOW_COPY_AND_ASSIGN(DownloadTestObserverTerminal);
+};
+
+// Detects changes to the downloads after construction.
+// Finishes when one of the following happens:
+//   - A specified number of downloads change to the IN_PROGRESS state.
+// Callers may either probe for the finished state, or wait on it.
+//
+class DownloadTestObserverInProgress : public DownloadTestObserverTerminal {

[Randy Smith (Not in Mondays), 2012/03/07 21:39:16]

This is test code, so I won't insist on a change, but the right thing to do here
is to have a separate class that has all the shared functionality for
*InProgress and *Terminal and have them both inherit from it.  If anyone were
ever to take a *InProgress and cast it to a *Terminal they'd get a really bad
surprise (which is what I meant by there not being an ISA relationship between
the two classes). 

It's possible that you could get the proper behavior (ban the ISA relationship)
by making the inheritance private (you'd probably need to write some wrapper
functions).  I don't know if that would work, but if it did, you'd make me
noticeably more comfortable about this implementation (it wouldn't be right, but
at least it wouldn't be broken anymore :-}).  If that doesn't work, please put
in a note saying "Inheritance purely for implementation convenience; there is no
ISA relationship between these classes and they should not be casted to each
other."

[ahendrickson, 2012/03/08 17:36:07]

Done.

+ public:
+  // Create an object that will be considered finished when |wait_count|
+  // download items have entered state |IN_PROGRESS|.
+
+  DownloadTestObserverInProgress(
+      content::DownloadManager* download_manager,
+      size_t wait_count);
+
+  virtual ~DownloadTestObserverInProgress();
+
+ private:
+  virtual bool IsDownloadInFinalState(content::DownloadItem* download) OVERRIDE;
+
+  DISALLOW_COPY_AND_ASSIGN(DownloadTestObserverInProgress);
 };
 
 // The WaitForFlush() method on this class returns after:
 //      * There are no IN_PROGRESS download items remaining on the
 //        DownloadManager.
 //      * There have been two round trip messages through the file and
 //        IO threads.
 // This almost certainly means that a Download cancel has propagated through
 // the system.
 class DownloadTestFlushObserver
@@ skipping 31 matching lines @@
   void PingIOThread(int cycle);
 
   content::DownloadManager* download_manager_;
   DownloadSet downloads_observed_;
   bool waiting_for_zero_inprogress_;
 
   DISALLOW_COPY_AND_ASSIGN(DownloadTestFlushObserver);
 };
 
 #endif  // CHROME_BROWSER_DOWNLOAD_DOWNLOAD_TEST_OBSERVER_H_