Moving Ordinal Specific Code out of ExtensionPrefs

Moved all of the ordinal specific code in ExtensionPrefs to a new class
ExtensionSorting, also moved the related unit tests to an ExtensionSorting
unit test file.

There are no logic changes in this patch.


BUG=104973
TEST=The icons on the NTP should behave the same as before, with users able to
move them around and remember position.


Review URL: http://codereview.chromium.org/9021034

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@117490 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 127 insertions, 0 deletions

diff --git a/chrome/browser/extensions/extension_sorting.h b/chrome/browser/extensions/extension_sorting.h
new file mode 100644
index 0000000..0a7e397
--- /dev/null
+++ b/chrome/browser/extensions/extension_sorting.h
@@ -0,0 +1,127 @@
+// 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_EXTENSIONS_EXTENSION_SORTING_H_
+#define CHROME_BROWSER_EXTENSIONS_EXTENSION_SORTING_H_
+#pragma once
+
+#include <string>
+
+#include "base/basictypes.h"
+#include "chrome/common/extensions/extension.h"
+#include "chrome/browser/extensions/extension_prefs.h"
+#include "chrome/common/string_ordinal.h"
+
+class ExtensionScopedPrefs;
+
+class ExtensionSorting {
+ public:
+  explicit ExtensionSorting(ExtensionScopedPrefs* extension_scoped_prefs,
+                            PrefService* pref_service);
+  ~ExtensionSorting();
+
+  // Migrates the app launcher and page index values.
+  void MigrateAppIndex(const ExtensionPrefs::ExtensionIdSet& extension_ids);
+
+  // Updates the app launcher value for the moved extension so that it is now
+  // located after the given predecessor and before the successor.
+  // Empty strings are used to indicate no successor or predecessor.
+  void OnExtensionMoved(const std::string& moved_extension_id,
+                        const std::string& predecessor_extension_id,
+                        const std::string& successor_extension_id);
+
+  // Get the application launch ordinal for an app with |extension_id|. This
+  // determines the order in which the app appears on the page it's on in the
+  // New Tab Page (Note that you can compare app launch ordinals only if the
+  // apps are on the same page). A string value close to |a*| generally
+  // indicates top left. If the extension has no launch ordinal, an invalid
+  // StringOrdinal is returned.
+  StringOrdinal GetAppLaunchOrdinal(const std::string& extension_id) const;
+
+  // Sets a specific launch ordinal for an app with |extension_id|.
+  void SetAppLaunchOrdinal(const std::string& extension_id,
+                           const StringOrdinal& ordinal);
+
+  // Returns a StringOrdinal that is lower than any app launch ordinal for the
+  // given page.
+  StringOrdinal CreateFirstAppLaunchOrdinal(const StringOrdinal& page_ordinal)
+      const;
+
+  // Returns a StringOrdinal that is higher than any app launch ordinal for the
+  // given page.
+  StringOrdinal CreateNextAppLaunchOrdinal(const StringOrdinal& page_ordinal)
+      const;
+
+  // Returns a StringOrdinal that is lower than any existing page ordinal.
+  StringOrdinal CreateFirstAppPageOrdinal() const;
+
+  // Gets the page a new app should install to, which is the earliest non-full
+  // page.  The returned ordinal may correspond to a page that doesn't yet exist
+  // if all pages are full.
+  StringOrdinal GetNaturalAppPageOrdinal() const;
+
+  // Get the page ordinal for an app with |extension_id|. This determines
+  // which page an app will appear on in page-based NTPs.  If the app has no
+  // page specified, an invalid StringOrdinal is returned.
+  StringOrdinal GetPageOrdinal(const std::string& extension_id) const;
+
+  // Sets a specific page ordinal for an app with |extension_id|.
+  void SetPageOrdinal(const std::string& extension_id,
+                      const StringOrdinal& ordinal);
+
+  // Removes the page ordinal for an app.
+  void ClearPageOrdinal(const std::string& extension_id);
+
+  // Convert the page StringOrdinal value to its integer equivalent. This takes
+  // O(# of apps) worst-case.
+  int PageStringOrdinalAsInteger(const StringOrdinal& page_ordinal) const;
+
+  // Converts the page index integer to its StringOrdinal equivalent. This takes
+  // O(# of apps) worst-case.
+  StringOrdinal PageIntegerAsStringOrdinal(size_t page_index) const;
+
+ private:
+  friend class ExtensionSortingGetMinOrMaxAppLaunchOrdinalsOnPage;
+    // Unit test.
+
+  // An enum used by GetMinOrMaxAppLaunchOrdinalsOnPage to specify which
+  // value should be returned.
+  enum AppLaunchOrdinalReturn {MIN_ORDINAL, MAX_ORDINAL};
+
+  // This function returns the lowest ordinal on |page_ordinal| if
+  // |return_value| == AppLaunchOrdinalReturn::MIN_ORDINAL, otherwise it returns
+  // the largest ordinal on |page_ordinal|. If there are no apps on the page
+  // then an invalid StringOrdinal is returned. It is an error to call this
+  // function with an invalid |page_ordinal|.
+  StringOrdinal GetMinOrMaxAppLaunchOrdinalsOnPage(
+      const StringOrdinal& page_ordinal,
+      AppLaunchOrdinalReturn return_type) const;
+
+  // Initialize the |page_ordinal_map_| with the page ordinals used by the
+  // given extensions.
+  void InitializePageOrdinalMap(
+      const ExtensionPrefs::ExtensionIdSet& extension_ids);
+
+  // Called when an application changes the value of its page ordinal so that
+  // |page_ordinal_map_| is aware that |old_value| page ordinal has been
+  // replace by the |new_value| page ordinal and adjusts its mapping
+  // accordingly. This works with valid and invalid StringOrdinals.
+  void UpdatePageOrdinalMap(const StringOrdinal& old_value,
+                            const StringOrdinal& new_value);
+
+  ExtensionScopedPrefs* extension_scoped_prefs_;  // Weak, owns this instance.
+  PrefService* pref_service_;  // Weak.
+
+  // A map of all the StringOrdinal page indices mapping to how often they are
+  // used, this is used for mapping the StringOrdinals to their integer
+  // equivalent as well as quick lookup of the sorted StringOrdinals.
+  // TODO(csharp) Convert this to a two-layer map to allow page ordinal lookup
+  // by id and vice versa.
+  typedef std::map<StringOrdinal, int, StringOrdinalLessThan> PageOrdinalMap;
+  PageOrdinalMap page_ordinal_map_;
+
+  DISALLOW_COPY_AND_ASSIGN(ExtensionSorting);
+};
+
+#endif  // CHROME_BROWSER_EXTENSIONS_EXTENSION_SORTING_H_