Convert app_launch_index and page_index from int to StringOrdinal.

chrome/browser/extensions/extension_prefs.h

Index: chrome/browser/extensions/extension_prefs.h
diff --git a/chrome/browser/extensions/extension_prefs.h b/chrome/browser/extensions/extension_prefs.h
index d7760a76d98a7210d7a0aae4bbb75cdd10689c7c..5bfc65ae781ecfec549ea17d8a10fe38c15e1582 100644
--- a/chrome/browser/extensions/extension_prefs.h
+++ b/chrome/browser/extensions/extension_prefs.h
@@ -16,6 +16,7 @@
 #include "chrome/browser/extensions/extension_prefs_scope.h"
 #include "chrome/browser/prefs/pref_service.h"
 #include "chrome/common/extensions/extension.h"
+#include "chrome/common/string_ordinal.h"
 #include "googleurl/src/gurl.h"
 
 class ExtensionPrefValueMap;
@@ -99,11 +100,12 @@ class ExtensionPrefs : public ExtensionContentSettingsStore::Observer {
   void SetToolbarOrder(const std::vector<std::string>& extension_ids);
 
   // Called when an extension is installed, so that prefs get created.
-  // If |page_index| is -1, and the then a page will be found for the App.
+  // If |page_ordinal| is an invalid ordinal, then a page will be found
+  // for the App.
   void OnExtensionInstalled(const Extension* extension,
                             Extension::State initial_state,
                             bool from_webstore,
-                            int page_index);
+                            StringOrdinal page_ordinal);
 
   // Called when an extension is uninstalled, so that prefs get cleaned up.
   void OnExtensionUninstalled(const std::string& extension_id,
@@ -304,36 +306,56 @@ class ExtensionPrefs : public ExtensionContentSettingsStore::Observer {
   bool GetWebStoreLogin(std::string* result);
   void SetWebStoreLogin(const std::string& login);
 
-  // Get the application launch index for an extension with |extension_id|. This
-  // determines the order of which the applications appear on the New Tab Page.
-  // A value of 0 generally indicates top left. If the extension has no launch
-  // index a -1 value is returned.
-  int GetAppLaunchIndex(const std::string& extension_id);
+  // Get the first page ordinal value.
+  StringOrdinal GetFirstAppPage() const;
 
-  // Sets a specific launch index for an extension with |extension_id|.
-  void SetAppLaunchIndex(const std::string& extension_id, int index);
+  // Create a StringOrdinal which will be the first element for the given page.
+  StringOrdinal CreateFirstAppLaunchOrdinal(const StringOrdinal& page_ordinal)
+      const;
 
-  // Gets the next available application launch index. This is 1 higher than the
-  // highest current application launch index found for the page |on_page|.
-  int GetNextAppLaunchIndex(int on_page);
+  // Get the application launch ordinal for an extension with |extension_id|.
+  // This determines the order of which the applications appear on the New Tab
+  // 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;
 
-  // Gets the page a new app should install to. Starts on page 0, and if there
-  // are N or more apps on it, tries to install on the next page.
-  int GetNaturalAppPageIndex();
+  // Sets a specific launch ordinal for an extension with |extension_id|.
+  void SetAppLaunchOrdinal(const std::string& extension_id,
+                           const StringOrdinal& ordinal);
+
+  // Gets the next available application launch ordinal. This is higher than the
+  // highest current application launch ordinal found for the page
+  // |page_ordinal|.
+  StringOrdinal GetNextAppLaunchOrdinal(const StringOrdinal& page_ordinal)
+      const;
+
+  // Gets the page a new app should install to. Starts on the first page, and if
+  // there are N or more apps on it, tries to install on the next page.
+  StringOrdinal GetNaturalAppPageOrdinal() const;
 
   // Sets the order the apps should be displayed in the app launcher.
-  void SetAppLauncherOrder(const std::vector<std::string>& extension_ids);
+  void SetAppLauncherOrder(const std::vector<std::string>& extension_ids,
+                           const std::string& moved_extension_id);
+
+  // Get the application page ordinal for an extension 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;
 
-  // Get the application page index for an extension with |extension_id|.  This
-  // determines which page an app will appear on in page-based NTPs.  If
-  // the app has no page specified, -1 is returned.
-  int GetPageIndex(const std::string& extension_id);
+  // Sets a specific page ordinal for an extension with |extension_id|.
+  void SetPageOrdinal(const std::string& extension_id,
+                      const StringOrdinal& ordinal);
 
-  // Sets a specific page index for an extension with |extension_id|.
-  void SetPageIndex(const std::string& extension_id, int index);
+  // Removes the page ordinal for an extension.
+  void ClearPageOrdinal(const std::string& extension_id);
 
-  // Removes the page index for an extension.
-  void ClearPageIndex(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);
 
   // Returns true if the user repositioned the app on the app launcher via drag
   // and drop.
@@ -457,6 +479,11 @@ class ExtensionPrefs : public ExtensionContentSettingsStore::Observer {
                              const std::string& pref_key,
                              const base::ListValue** out_value);
 
+  // Reads a string pref |pref_key| from extension with id |extension_id|.
+  bool ReadExtensionPrefString(const std::string& extension_id,
+                               const std::string& pref_key,
+                               std::string* out_value) const;
+
   // Interprets the list pref, |pref_key| in |extension_id|'s preferences, as a
   // URLPatternSet. The |valid_schemes| specify how to parse the URLPatterns.
   bool ReadExtensionPrefURLPatternSet(const std::string& extension_id,
@@ -514,17 +541,47 @@ class ExtensionPrefs : public ExtensionContentSettingsStore::Observer {
   // Migrates the permissions data in the pref store.
   void MigratePermissions(const ExtensionIdSet& extension_ids);
 
+  // Migrates the app launcher and page index values.
+  void MigrateAppIndex(const ExtensionIdSet& extension_ids);
+
   // Checks whether there is a state pref for the extension and if so, whether
   // it matches |check_state|.
   bool DoesExtensionHaveState(const std::string& id,
                               Extension::State check_state) const;
 
+  // If page |page_ordinal| contains at least 1 apps, this function returns
+  // true with |min_app_launch_value| containing the lowest ordinal on the page
+  // and |max_app_launch_value| containing the largest ordinal on the page. If
+  // there are no apps on the page this function returns false. It is an
+  // error to call this function with an invalid |page_ordinal| or
+  // NULl values for |min_app_launch_value| or |max_app_launch_value|.
+  bool GetMaxAndMinAppLaunchOrdinalsOnPage(
+      const StringOrdinal& page_ordinal,
+      StringOrdinal* min_app_launch_value,
+      StringOrdinal* max_app_launch_value) const;
+
+  // Initialize the |page_ordinal_map_| with the page ordinals used by the
+  // given extensions.
+  void InitializePageOrdinalMap(const 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);
+
   // The pref service specific to this set of extension prefs. Owned by profile.
   PrefService* prefs_;
 
   // Base extensions install directory.
   FilePath install_directory_;
 
+  // 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.
+  std::map<StringOrdinal, int, StringOrdinalLessThan> page_ordinal_map_;
+
   // Weak pointer, owned by Profile.
   ExtensionPrefValueMap* extension_pref_value_map_;