root/ui/app_list/app_list_item_list.cc

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DEFINITIONS

This source file includes following definitions.
  1. AddObserver
  2. RemoveObserver
  3. FindItem
  4. FindItemIndex
  5. MoveItem
  6. SetItemPosition
  7. CreatePositionBefore
  8. AddItem
  9. DeleteItem
  10. RemoveItem
  11. RemoveItemAt
  12. DeleteItemAt
  13. EnsureValidItemPosition
  14. GetItemSortOrderIndex
  15. FixItemPosition

// 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 "ui/app_list/app_list_item_list.h"

#include "ui/app_list/app_list_item.h"

namespace app_list {

AppListItemList::AppListItemList() {
}

AppListItemList::~AppListItemList() {
}

void AppListItemList::AddObserver(AppListItemListObserver* observer) {
  observers_.AddObserver(observer);
}

void AppListItemList::RemoveObserver(AppListItemListObserver* observer) {
  observers_.RemoveObserver(observer);
}

AppListItem* AppListItemList::FindItem(const std::string& id) {
  for (size_t i = 0; i < app_list_items_.size(); ++i) {
    AppListItem* item = app_list_items_[i];
    if (item->id() == id)
      return item;
  }
  return NULL;
}

bool AppListItemList::FindItemIndex(const std::string& id, size_t* index) {
  for (size_t i = 0; i < app_list_items_.size(); ++i) {
    AppListItem* item = app_list_items_[i];
    if (item->id() == id) {
      *index = i;
      return true;
    }
  }
  return false;
}

void AppListItemList::MoveItem(size_t from_index, size_t to_index) {
  DCHECK_LT(from_index, item_count());
  DCHECK_LT(to_index, item_count());
  if (from_index == to_index)
    return;

  AppListItem* target_item = app_list_items_[from_index];
  DVLOG(2) << "MoveItem: " << from_index << " -> " << to_index << " ["
           << target_item->position().ToDebugString() << "]";

  // Remove the target item
  app_list_items_.weak_erase(app_list_items_.begin() + from_index);

  // Update the position
  AppListItem* prev = to_index > 0 ? app_list_items_[to_index - 1] : NULL;
  AppListItem* next =
      to_index < item_count() ? app_list_items_[to_index] : NULL;
  CHECK_NE(prev, next);
  syncer::StringOrdinal new_position;
  if (!prev) {
    new_position = next->position().CreateBefore();
  } else if (!next) {
    new_position = prev->position().CreateAfter();
  } else {
    // It is possible that items were added with the same ordinal. To
    // successfully move the item we need to fix this. We do not try to fix this
    // when an item is added in order to avoid possible edge cases with sync.
    if (prev->position().Equals(next->position()))
      FixItemPosition(to_index);
    new_position = prev->position().CreateBetween(next->position());
  }
  target_item->set_position(new_position);

  DVLOG(2) << "Move: "
           << " Prev: " << (prev ? prev->position().ToDebugString() : "(none)")
           << " Next: " << (next ? next->position().ToDebugString() : "(none)")
           << " -> " << new_position.ToDebugString();

  // Insert the item and notify observers.
  app_list_items_.insert(app_list_items_.begin() + to_index, target_item);
  FOR_EACH_OBSERVER(AppListItemListObserver,
                    observers_,
                    OnListItemMoved(from_index, to_index, target_item));
}

void AppListItemList::SetItemPosition(AppListItem* item,
                                      syncer::StringOrdinal new_position) {
  DCHECK(item);
  size_t from_index;
  if (!FindItemIndex(item->id(), &from_index)) {
    LOG(ERROR) << "SetItemPosition: Not in list: " << item->id().substr(0, 8);
    return;
  }
  DCHECK(app_list_items_[from_index] == item);
  if (!new_position.IsValid()) {
    size_t last_index = app_list_items_.size() - 1;
    if (from_index == last_index)
      return;  // Already last item, do nothing.
    new_position = app_list_items_[last_index]->position().CreateAfter();
  }
  // First check if the order would remain the same, in which case just update
  // the position.
  size_t to_index = GetItemSortOrderIndex(new_position, item->id());
  if (to_index == from_index) {
    DVLOG(2) << "SetItemPosition: No change: " << item->id().substr(0, 8);
    item->set_position(new_position);
    return;
  }
  // Remove the item and get the updated to index.
  app_list_items_.weak_erase(app_list_items_.begin() + from_index);
  to_index = GetItemSortOrderIndex(new_position, item->id());
  DVLOG(2) << "SetItemPosition: " << item->id().substr(0, 8) << " -> "
           << new_position.ToDebugString() << " From: " << from_index
           << " To: " << to_index;
  item->set_position(new_position);
  app_list_items_.insert(app_list_items_.begin() + to_index, item);
  FOR_EACH_OBSERVER(AppListItemListObserver,
                    observers_,
                    OnListItemMoved(from_index, to_index, item));
}

// AppListItemList private

syncer::StringOrdinal AppListItemList::CreatePositionBefore(
    const syncer::StringOrdinal& position) {
  if (app_list_items_.empty())
    return syncer::StringOrdinal::CreateInitialOrdinal();

  size_t nitems = app_list_items_.size();
  size_t index;
  if (!position.IsValid()) {
    index = nitems;
  } else {
    for (index = 0; index < nitems; ++index) {
      if (!app_list_items_[index]->position().LessThan(position))
        break;
    }
  }
  if (index == 0)
    return app_list_items_[0]->position().CreateBefore();
  if (index == nitems)
    return app_list_items_[nitems - 1]->position().CreateAfter();
  return app_list_items_[index - 1]->position().CreateBetween(
      app_list_items_[index]->position());
}

AppListItem* AppListItemList::AddItem(scoped_ptr<AppListItem> item_ptr) {
  AppListItem* item = item_ptr.get();
  CHECK(std::find(app_list_items_.begin(), app_list_items_.end(), item)
        == app_list_items_.end());
  EnsureValidItemPosition(item);
  size_t index = GetItemSortOrderIndex(item->position(), item->id());
  app_list_items_.insert(app_list_items_.begin() + index, item_ptr.release());
  FOR_EACH_OBSERVER(AppListItemListObserver,
                    observers_,
                    OnListItemAdded(index, item));
  return item;
}

void AppListItemList::DeleteItem(const std::string& id) {
  scoped_ptr<AppListItem> item = RemoveItem(id);
  // |item| will be deleted on destruction.
}

scoped_ptr<AppListItem> AppListItemList::RemoveItem(
    const std::string& id) {
  size_t index;
  if (FindItemIndex(id, &index))
    return RemoveItemAt(index);

  return scoped_ptr<AppListItem>();
}

scoped_ptr<AppListItem> AppListItemList::RemoveItemAt(size_t index) {
  DCHECK_LT(index, item_count());
  AppListItem* item = app_list_items_[index];
  app_list_items_.weak_erase(app_list_items_.begin() + index);
  FOR_EACH_OBSERVER(AppListItemListObserver,
                    observers_,
                    OnListItemRemoved(index, item));
  return make_scoped_ptr<AppListItem>(item);
}

void AppListItemList::DeleteItemAt(size_t index) {
  scoped_ptr<AppListItem> item = RemoveItemAt(index);
  // |item| will be deleted on destruction.
}

void AppListItemList::EnsureValidItemPosition(AppListItem* item) {
  syncer::StringOrdinal position = item->position();
  if (position.IsValid())
    return;
  size_t nitems = app_list_items_.size();
  if (nitems == 0) {
    position = syncer::StringOrdinal::CreateInitialOrdinal();
  } else {
    position = app_list_items_[nitems - 1]->position().CreateAfter();
  }
  item->set_position(position);
}

size_t AppListItemList::GetItemSortOrderIndex(
    const syncer::StringOrdinal& position,
    const std::string& id) {
  DCHECK(position.IsValid());
  for (size_t index = 0; index < app_list_items_.size(); ++index) {
    if (position.LessThan(app_list_items_[index]->position()) ||
        (position.Equals(app_list_items_[index]->position()) &&
         (id < app_list_items_[index]->id()))) {
      return index;
    }
  }
  return app_list_items_.size();
}

void AppListItemList::FixItemPosition(size_t index) {
  DVLOG(1) << "FixItemPosition: " << index;
  size_t nitems = item_count();
  DCHECK_LT(index, nitems);
  DCHECK_GT(index, 0u);
  // Update the position of |index| and any necessary subsequent items.
  // First, find the next item that has a different position.
  AppListItem* prev = app_list_items_[index - 1];
  size_t last_index = index + 1;
  for (; last_index < nitems; ++last_index) {
    if (!app_list_items_[last_index]->position().Equals(prev->position()))
      break;
  }
  AppListItem* last = last_index < nitems ? app_list_items_[last_index] : NULL;
  for (size_t i = index; i < last_index; ++i) {
    AppListItem* cur = app_list_items_[i];
    if (last)
      cur->set_position(prev->position().CreateBetween(last->position()));
    else
      cur->set_position(prev->position().CreateAfter());
    prev = cur;
  }
  FOR_EACH_OBSERVER(AppListItemListObserver,
                    observers_,
                    OnListItemMoved(index, index, app_list_items_[index]));
}

}  // namespace app_list

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