Improvements in --debug-print switch implementation.

printing/printed_document.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 PRINTING_PRINTED_DOCUMENT_H_
 #define PRINTING_PRINTED_DOCUMENT_H_
 
 #include <map>
 
 #include "base/memory/ref_counted.h"
 #include "base/strings/string16.h"
 #include "base/synchronization/lock.h"
 #include "printing/print_settings.h"
 #include "ui/gfx/native_widget_types.h"
 
 namespace base {
 class FilePath;
-class MessageLoop;
+class RefCountedMemory;
+class TaskRunner;
 }
 
 namespace printing {
 
 class Metafile;
 class PrintedPage;
 class PrintedPagesSource;
 class PrintingContext;
 
 // A collection of rendered pages. The settings are immutable. If the print
 // settings are changed, a new PrintedDocument must be created.
 // Warning: May be accessed from many threads at the same time. Only one thread
 // will have write access. Sensible functions are protected by a lock.
 // Warning: Once a page is loaded, it cannot be replaced. Pages may be discarded
 // under low memory conditions.
 class PRINTING_EXPORT PrintedDocument
     : public base::RefCountedThreadSafe<PrintedDocument> {
  public:
   // The cookie shall be unique and has a specific relationship with its
   // originating source and settings.
   PrintedDocument(const PrintSettings& settings,
                   PrintedPagesSource* source,
-                  int cookie);
+                  int cookie,
+                  base::TaskRunner* file_runner);
 
   // Sets a page's data. 0-based. Takes metafile ownership.
   // Note: locks for a short amount of time.
   void SetPage(int page_number, Metafile* metafile, double shrink,
                const gfx::Size& paper_size, const gfx::Rect& page_rect);
 
   // Retrieves a page. If the page is not available right now, it
-  // requests to have this page be rendered and returns false.
+  // requests to have this page be rendered and returns NULL.
   // Note: locks for a short amount of time.
-  bool GetPage(int page_number, scoped_refptr<PrintedPage>* page);
+  scoped_refptr<PrintedPage> GetPage(int page_number);
 
   // Draws the page in the context.
   // Note: locks for a short amount of time in debug only.
 #if defined(OS_WIN) || defined(OS_MACOSX) && !defined(USE_AURA)
   void RenderPrintedPage(const PrintedPage& page,
                          gfx::NativeDrawingContext context) const;
 #elif defined(OS_POSIX)
   void RenderPrintedPage(const PrintedPage& page,
                          PrintingContext* context) const;
 #endif
@@ skipping 28 matching lines @@
 
   // Getters. All these items are immutable hence thread-safe.
   const PrintSettings& settings() const { return immutable_.settings_; }
   const base::string16& name() const { return immutable_.name_; }
   int cookie() const { return immutable_.cookie_; }
 
   // Sets a path where to dump printing output files for debugging. If never set
   // no files are generated.
   static void set_debug_dump_path(const base::FilePath& debug_dump_path);
 
-  static const base::FilePath& debug_dump_path();
+  // Creates debug file name from given |document_name| and |extension|.
+  // Returns empty |base::FilePath| if debug dumps is not enabled.
+  static base::FilePath CreateDebugDumpPath(const base::string16& document_name,
+                                            const std::string& extension);
+
+  // Dump data on FILE thread if debug dumps enabled.

[Lei Zhang, 2014/06/11 21:43:42]

- Update the comment if you use GetBlockingPool().
- Mention whether |extension| requires a '.' or not. FilePath::Extension()
returns ".foo" FWIW.

[Vitaly Buka (NO REVIEWS), 2014/06/11 22:22:58]

Done.

+  void DebugDumpData(const base::RefCountedMemory* data,
+                     const std::string& extension);
 
  private:
   friend class base::RefCountedThreadSafe<PrintedDocument>;
 
   virtual ~PrintedDocument();
 
   // Array of data for each print previewed page.
   typedef std::map<int, scoped_refptr<PrintedPage> > PrintedPages;
 
   // Contains all the mutable stuff. All this stuff MUST be accessed with the
@@ skipping 20 matching lines @@
 #if defined(OS_POSIX) && !defined(OS_MACOSX)
     // Page number of the first page.
     int first_page;
 #endif
   };
 
   // Contains all the immutable stuff. All this stuff can be accessed without
   // any lock held. This is because it can't be changed after the object's
   // construction.
   struct Immutable {
-    Immutable(const PrintSettings& settings, PrintedPagesSource* source,
-              int cookie);
+    Immutable(const PrintSettings& settings,
+              PrintedPagesSource* source,
+              int cookie,
+              base::TaskRunner* file_runner);
     ~Immutable();
 
     // Print settings used to generate this document. Immutable.
     PrintSettings settings_;
 
-    // Native thread for the render source.
-    base::MessageLoop* source_message_loop_;
+    // Native thread for file operations.
+    scoped_refptr<base::TaskRunner> file_runner_;
 
     // Document name. Immutable.
     base::string16 name_;
 
     // Cookie to uniquely identify this document. It is used to make sure that a
     // PrintedPage is correctly belonging to the PrintedDocument. Since
     // PrintedPage generation is completely asynchronous, it could be easy to
     // mess up and send the page to the wrong document. It can be viewed as a
     // simpler hash of PrintSettings since a new document is made each time the
     // print settings change.
     int cookie_;
   };
 
-  void DebugDump(const PrintedPage& page);
-
   // All writable data member access must be guarded by this lock. Needs to be
   // mutable since it can be acquired from const member functions.
   mutable base::Lock lock_;
 
   // All the mutable members.
   Mutable mutable_;
 
   // All the immutable members.
   const Immutable immutable_;
 
   DISALLOW_COPY_AND_ASSIGN(PrintedDocument);
 };
 
 }  // namespace printing
 
 #endif  // PRINTING_PRINTED_DOCUMENT_H_