Separate the NTP app ordering from the app list app ordering

chrome/browser/ui/app_list/app_list_extension_sorting.cc

Index: chrome/browser/ui/app_list/app_list_extension_sorting.cc
diff --git a/chrome/browser/ui/app_list/app_list_extension_sorting.cc b/chrome/browser/ui/app_list/app_list_extension_sorting.cc
new file mode 100644
index 0000000000000000000000000000000000000000..46c8eecd9392d342369aa0976258f18c89efe157
--- /dev/null
+++ b/chrome/browser/ui/app_list/app_list_extension_sorting.cc
@@ -0,0 +1,329 @@
+// Copyright (c) 2013 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.
+
+#include "chrome/browser/chrome_notification_types.h"
+#include "chrome/browser/extensions/extension_prefs.h"
+#include "chrome/browser/extensions/extension_service.h"
+#include "chrome/browser/ui/app_list/app_list_extension_sorting.h"
+#include "chrome/browser/ui/app_list/app_list_extension_sorting_observer.h"
+#include "content/public/browser/notification_service.h"
+
+#if defined(OS_CHROMEOS)
+#include "chrome/browser/chromeos/extensions/default_app_order.h"
+#endif
+
+namespace {
+
+const char kPrefAppListOrdinal[] = "app_list_ordinal";
+
+}  // namespace
+
+AppListExtensionSorting::AppListExtensionSorting(
+    ExtensionScopedPrefs* extension_scoped_prefs)
+    : extension_scoped_prefs_(extension_scoped_prefs),
+      extension_service_(NULL) {}
+
+AppListExtensionSorting::~AppListExtensionSorting() {}
+
+void AppListExtensionSorting::Initialize(
+    const extensions::ExtensionIdList& extension_ids,
+    const extensions::ExtensionIdList& ntp_sorted_extension_ids) {
+  ExtensionIdSet uninitialized_extensions;
+  for (extensions::ExtensionIdList::const_iterator ext_it =
+       extension_ids.begin(); ext_it != extension_ids.end(); ++ext_it) {
+    if (!InitializeOrdinalFromPrefs(*ext_it))
+      uninitialized_extensions.insert(*ext_it);
+    // Ensure that the web store app still isn't found in this list, since
+    // it is added after this loop.
+    DCHECK(*ext_it != extension_misc::kWebStoreAppId);
+    DCHECK(*ext_it != extension_misc::kChromeAppId);
+  }
+
+  // Include the Web Store App since it is displayed on the app list.
+  if (!InitializeOrdinalFromPrefs(extension_misc::kWebStoreAppId))
+    uninitialized_extensions.insert(extension_misc::kWebStoreAppId);
+  // Include the Chrome App since it is displayed on the app list.
+  if (!InitializeOrdinalFromPrefs(extension_misc::kChromeAppId))
+    uninitialized_extensions.insert(extension_misc::kChromeAppId);
+
+  // Copy NTP app order into new pref.
+  InitializeFromNTPExtensionSorting(ntp_sorted_extension_ids,
+                                    &uninitialized_extensions);
+
+  InitializeWithDefaultOrdinals(uninitialized_extensions);
+}
+
+bool AppListExtensionSorting::InitializeOrdinalFromPrefs(
+    const std::string& extension_id) {
+  syncer::StringOrdinal ordinal = GetAppListOrdinalFromPrefs(extension_id);
+
+  if (ordinal.IsValid())
+    SetAppListOrdinal(extension_id, ordinal);
+  return ordinal.IsValid();
+}
+
+void AppListExtensionSorting::InitializeFromNTPExtensionSorting(
+    const extensions::ExtensionIdList& ntp_sorted_extension_ids,
+    ExtensionIdSet* uninitialized_extensions) {
+  for (extensions::ExtensionIdList::const_iterator ntp_it =
+           ntp_sorted_extension_ids.begin();
+       ntp_it != ntp_sorted_extension_ids.end(); ++ntp_it) {
+    if (uninitialized_extensions->count(*ntp_it)) {
+      syncer::StringOrdinal ordinal = app_list_ordinal_map_.empty()
+          ? syncer::StringOrdinal::CreateInitialOrdinal()
+          : app_list_ordinal_map_.rbegin()->first.CreateAfter();
+      SetAppListOrdinal(*ntp_it, ordinal);
+      UpdatePrefs(*ntp_it, ordinal);
+      uninitialized_extensions->erase(*ntp_it);
+    }
+  }
+}
+
+void AppListExtensionSorting::InitializeWithDefaultOrdinals(
+    const ExtensionIdSet& uninitialized_extensions) {
+  // The following defines the default order of apps.
+#if defined(OS_CHROMEOS)
+  std::vector<std::string> default_app_order;
+  chromeos::default_app_order::Get(&default_app_order);
+#else
+  const char* kDefaultAppOrder[] = {
+    extension_misc::kChromeAppId,
+    extension_misc::kWebStoreAppId,
+  };
+  const std::vector<const char*> default_app_order(
+      kDefaultAppOrder, kDefaultAppOrder + arraysize(kDefaultAppOrder));
+#endif
+
+  syncer::StringOrdinal ordinal = app_list_ordinal_map_.empty()
+      ? syncer::StringOrdinal::CreateInitialOrdinal()
+      : app_list_ordinal_map_.begin()->first.CreateBefore();
+
+  // Create a map of extension ids to their default ordinals. The first ordinal
+  // used will precede all ordinals in the app list. Subsequent ordinals are
+  // created between this starting ordinal and the first ordinal in the app
+  // list.
+  std::map<std::string, syncer::StringOrdinal> default_ordinals;
+  for (size_t i = 0; i < default_app_order.size(); ++i) {
+    const std::string extension_id = default_app_order[i];
+    default_ordinals[extension_id] = ordinal;
+    ordinal = app_list_ordinal_map_.empty()
+        ? ordinal.CreateAfter()
+        : ordinal.CreateBetween(app_list_ordinal_map_.begin()->first);
+  }
+
+  // Set default ordinals only for uninitialized extensions.
+  for (ExtensionIdSet::const_iterator it = uninitialized_extensions.begin();
+      it != uninitialized_extensions.end(); ++it) {
+    std::map<std::string, syncer::StringOrdinal>::const_iterator default_it =
+        default_ordinals.find(*it);
+    if (default_it != default_ordinals.end()) {
+      SetAppListOrdinal(*it, default_it->second);
+      UpdatePrefs(*it, default_it->second);
+      default_initialized_extensions_.push_back(*it);
+    }
+  }
+}
+
+void AppListExtensionSorting::FixSyncCollisions() {
+  for (AppListOrdinalMap::iterator ordinal_map_it =
+          app_list_ordinal_map_.begin();
+      ordinal_map_it != app_list_ordinal_map_.end(); ++ordinal_map_it) {
+    syncer::StringOrdinal repeated_ordinal = ordinal_map_it->first;
+    ExtensionIdSet& extension_set = ordinal_map_it->second;
+    if (extension_set.size() == 1)
+      continue;
+    // Assign unique ordinals to conflicting extensions by assigning new
+    // ordinals between the conflict ordinal and the next ordinal.
+    AppListOrdinalMap::iterator next_it = ordinal_map_it;
+    std::advance(next_it, 1);
+
+    syncer::StringOrdinal upper_bound_ordinal =
+        next_it == app_list_ordinal_map_.end() ? syncer::StringOrdinal()
+                                               : next_it->first;
+    syncer::StringOrdinal lower_bound_ordinal = repeated_ordinal;
+    std::vector<std::string> conflicting_ids(extension_set.begin(),
+                                             extension_set.end());
+    // Skip the first conflicting extension because the first extension can keep
+    // the conflicted ordinal. Unique ordinals will be assigned so that
+    // conflicts are sorted by their extension ids.
+    for (size_t i = 1; i < conflicting_ids.size(); ++i) {
+      syncer::StringOrdinal unique_ordinal;
+      if (upper_bound_ordinal.IsValid()) {
+        unique_ordinal =
+            lower_bound_ordinal.CreateBetween(upper_bound_ordinal);
+      } else {
+        unique_ordinal = lower_bound_ordinal.CreateAfter();
+      }
+      EraseAppListOrdinal(conflicting_ids[i]);
+      SetAppListOrdinal(conflicting_ids[i], unique_ordinal);
+      UpdatePrefs(conflicting_ids[i], unique_ordinal);
+      lower_bound_ordinal = unique_ordinal;
+    }
+  }
+
+  FOR_EACH_OBSERVER(AppListExtensionSortingObserver, observers_,
+                    OnAppListReordered());
+}
+
+void AppListExtensionSorting::InsertAtFront(const std::string& extension_id) {
+  DCHECK(!Contains(extension_id));
+  syncer::StringOrdinal ordinal = app_list_ordinal_map_.empty()
+      ? syncer::StringOrdinal::CreateInitialOrdinal()
+      : app_list_ordinal_map_.begin()->first.CreateBefore();
+  SetAppListOrdinal(extension_id, ordinal);
+  UpdatePrefs(extension_id, ordinal);
+}
+
+void AppListExtensionSorting::InsertAtBack(const std::string& extension_id) {
+  DCHECK(!Contains(extension_id));
+  syncer::StringOrdinal ordinal = app_list_ordinal_map_.empty()
+      ? syncer::StringOrdinal::CreateInitialOrdinal()
+      : app_list_ordinal_map_.rbegin()->first.CreateAfter();
+  SetAppListOrdinal(extension_id, ordinal);
+  UpdatePrefs(extension_id, ordinal);
+}
+
+void AppListExtensionSorting::OnExtensionMoved(
+    const std::string& moved_extension_id,
+    const std::string& predecessor_extension_id,
+    const std::string& successor_extension_id) {
+  const syncer::StringOrdinal& predecessor_ordinal =
+      predecessor_extension_id.empty() ?
+          syncer::StringOrdinal() :
+          GetAppListOrdinalFromPrefs(predecessor_extension_id);
+  const syncer::StringOrdinal& successor_ordinal =
+      successor_extension_id.empty() ?
+          syncer::StringOrdinal() :
+          GetAppListOrdinalFromPrefs(successor_extension_id);
+  // We only need to change the StringOrdinal if there is at least one
+  // neighbour.
+  if (predecessor_ordinal.IsValid() || successor_ordinal.IsValid()) {
+    syncer::StringOrdinal ordinal;
+    if (!predecessor_ordinal.IsValid()) {
+      // Only a successor.
+      ordinal = successor_ordinal.CreateBefore();
+    } else if (!successor_ordinal.IsValid()) {
+      // Only a predecessor.
+      ordinal = predecessor_ordinal.CreateAfter();
+    } else {
+      // Both a successor and predecessor
+      ordinal = predecessor_ordinal.CreateBetween(successor_ordinal);
+    }
+    EraseAppListOrdinal(moved_extension_id);
+    SetAppListOrdinal(moved_extension_id, ordinal);
+    UpdatePrefs(moved_extension_id, ordinal);
+  }
+
+  FOR_EACH_OBSERVER(AppListExtensionSortingObserver, observers_,
+                    OnAppListReordered());
+}
+
+void AppListExtensionSorting::Erase(const std::string& extension_id) {
+  EraseAppListOrdinal(extension_id);
+  UpdatePrefs(extension_id, syncer::StringOrdinal());
+}
+
+void AppListExtensionSorting::EraseAppListOrdinal(
+    const std::string& extension_id) {
+  if (!Contains(extension_id))
+    return;
+  AppListOrdinalMap::iterator ordinal_map_it =
+      app_list_ordinal_map_.find(GetAppListOrdinalFromPrefs(extension_id));
+  if (ordinal_map_it == app_list_ordinal_map_.end())
+    NOTREACHED();
+  ordinal_map_it->second.erase(extension_id);
+  if (ordinal_map_it->second.empty())
+    app_list_ordinal_map_.erase(ordinal_map_it);
+}
+
+bool AppListExtensionSorting::ExtensionPrecedes(
+    const std::string& extension_id1,
+    const std::string& extension_id2) {
+  DCHECK(Contains(extension_id1) && Contains(extension_id2));
+  return GetAppListOrdinalFromPrefs(extension_id1).LessThan(
+      GetAppListOrdinalFromPrefs(extension_id2));
+}
+
+bool AppListExtensionSorting::Contains(const std::string& extension_id) {
+  if (!GetAppListOrdinalFromPrefs(extension_id).IsValid())
+    return false;
+
+  AppListOrdinalMap::iterator ordinal_map_it =
+      app_list_ordinal_map_.find(GetAppListOrdinalFromPrefs(extension_id));
+  if (ordinal_map_it == app_list_ordinal_map_.end())
+    return false;
+  return ordinal_map_it->second.count(extension_id) > 0;
+}
+
+syncer::StringOrdinal AppListExtensionSorting::GetAppListOrdinalFromPrefs(
+    const std::string& extension_id) {
+  std::string raw_data;
+  // If the preference read fails then raw_data will still be unset and we will
+  // return an invalid StringOrdinal to signal that no app list ordinal was
+  // found.
+  extension_scoped_prefs_->ReadPrefAsString(
+      extension_id, kPrefAppListOrdinal, &raw_data);
+  return syncer::StringOrdinal(raw_data);
+}
+
+void AppListExtensionSorting::UpdateAppListOrdinalFromSync(
+  const std::string& extension_id,
+  const syncer::StringOrdinal& ordinal) {
+  EraseAppListOrdinal(extension_id);
+  SetAppListOrdinal(extension_id, ordinal);
+  UpdatePrefs(extension_id, ordinal);
+}
+
+void AppListExtensionSorting::SetAppListOrdinal(
+    const std::string& extension_id,
+    const syncer::StringOrdinal& ordinal) {
+  app_list_ordinal_map_[ordinal].insert(extension_id);
+}
+
+void AppListExtensionSorting::UpdatePrefs(
+    const std::string& extension_id,
+    const syncer::StringOrdinal& ordinal) {
+  if (ordinal.EqualsOrBothInvalid(GetAppListOrdinalFromPrefs(extension_id)))
+    return;
+
+  Value* new_value = ordinal.IsValid() ?
+      Value::CreateStringValue(ordinal.ToInternalValue()) :
+      NULL;
+  extension_scoped_prefs_->UpdateExtensionPref(
+      extension_id,
+      kPrefAppListOrdinal,
+      new_value);
+
+  if (!extension_service_)
+    return;
+
+  // Sync extension pref.
+  const extensions::Extension* extension =
+      extension_service_->GetInstalledExtension(extension_id);
+  if (extension)
+    extension_service_->SyncExtensionChangeIfNeeded(*extension);
+}
+
+void AppListExtensionSorting::SetExtensionService(
+    ExtensionServiceInterface* extension_service) {
+  extension_service_ = extension_service;
+  for (size_t i = 0; i < default_initialized_extensions_.size(); ++i) {
+    const extensions::Extension* extension =
+      extension_service_->GetInstalledExtension(
+          default_initialized_extensions_[i]);
+    if (extension)
+      extension_service_->SyncExtensionChangeIfNeeded(*extension);
+  }
+  default_initialized_extensions_.clear();
+}
+
+void AppListExtensionSorting::AddObserver(
+      AppListExtensionSortingObserver* observer) {
+  observers_.AddObserver(observer);
+}
+
+void AppListExtensionSorting::RemoveObserver(
+      AppListExtensionSortingObserver* observer) {
+  observers_.RemoveObserver(observer);
+}