components/offline_pages/offline_page_archiver.h

   1 // Copyright 2015 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #ifndef COMPONENTS_OFFLINE_PAGES_OFFLINE_PAGE_ARCHIVER_H_
   6 #define COMPONENTS_OFFLINE_PAGES_OFFLINE_PAGE_ARCHIVER_H_
   7
   8 #include "base/callback.h"
   9 #include "base/files/file_path.h"
  10 #include "base/strings/string16.h"
  11 #include "url/gurl.h"
  12
  13 namespace offline_pages {
  14
  15 // Interface of a class responsible for creation of the archive for offline use.
  16 //
  17 // Archiver will be implemented by embedder and may have additional methods that
  18 // are not interesting from the perspective of OfflinePageModel. Example of such
  19 // extra information or capability is a way to enumerate available WebContents
  20 // to find the one that needs to be used to create archive (or to map it to the
  21 // URL passed in CreateArchive in some other way).
  22 //
  23 // Archiver will be responsible for naming the file that is being saved (it has
  24 // URL, title and the whole page content at its disposal). For that it should be
  25 // also configured with the path where the archives are stored.
  26 //
  27 // Archiver should be able to archive multiple pages in parallel, as these are
  28 // asynchronous calls carried out by some other component.
  29 //
  30 // If archiver gets two consecutive requests to archive the same page (may be
  31 // run in parallel) it can generate 2 different names for files and save the
  32 // same page separately, as if these were 2 completely unrelated pages. It is up
  33 // to the caller (e.g. OfflinePageModel) to make sure that situation like that
  34 // does not happen.
  35 //
  36 // If the page is not completely loaded, it is up to the implementation of the
  37 // archiver whether to respond with ERROR_CONTENT_UNAVAILBLE, wait longer to
  38 // actually snapshot a complete page, or snapshot whatever is available at that
  39 // point in time (what the user sees).
  40 //
  41 // TODO(fgorski): Add ability to delete archive.
  42 // TODO(fgorski): Add ability to check that archive exists.
  43 // TODO(fgorski): Add ability to refresh an existing archive in one step.
  44 // TODO(fgorski): Add ability to identify all of the archives in the directory,
  45 // to enable to model to reconcile the archives.
  46 class OfflinePageArchiver {
  47  public:
  48   // Results of the archive creation.
  49   enum class ArchiverResult {
  50     SUCCESSFULLY_CREATED,           // Archive created successfully.
  51     ERROR_DEVICE_FULL,              // Cannot save the archive - device is full.
  52     ERROR_CANCELED,                 // Caller canceled the request.
  53     ERROR_CONTENT_UNAVAILABLE,      // Content to archive is not available.
  54     ERROR_ARCHIVE_CREATION_FAILED,  // Creation of archive failed.
  55   };
  56
  57   typedef base::Callback<void(OfflinePageArchiver* /* archiver */,
  58                               ArchiverResult /* result */,
  59                               const GURL& /* url */,
  60                               const base::FilePath& /* file_path */,
  61                               int64 /* file_size */)> CreateArchiveCallback;
  62
  63   virtual ~OfflinePageArchiver() {}
  64
  65   // Starts creating the archive. Once archive is created |callback| will be
  66   // called with the result and additional information.
  67   virtual void CreateArchive(const CreateArchiveCallback& callback) = 0;
  68 };
  69
  70 }  // namespace offline_pages
  71
  72 #endif  // COMPONENTS_OFFLINE_PAGES_OFFLINE_PAGE_ARCHIVER_H_