xiaomi/src/data/NotesProvider.java

/*
 * Copyright (c) 2010-2011, The MiCode Open Source Community (www.micode.net)
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *        http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package net.micode.notes.data;


import android.app.SearchManager;
import android.content.ContentProvider;
import android.content.ContentUris;
import android.content.ContentValues;
import android.content.Intent;
import android.content.UriMatcher;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.net.Uri;
import android.text.TextUtils;
import android.util.Log;

import net.micode.notes.R;
import net.micode.notes.data.Notes.DataColumns;
import net.micode.notes.data.Notes.NoteColumns;
import net.micode.notes.data.NotesDatabaseHelper.TABLE;


/**
 * 笔记内容提供者，实现了ContentProvider接口
 * 提供对笔记和数据的CRUD操作，使用UriMatcher处理不同的URI请求
 * 是应用与数据库之间的桥梁，被其他模块通过ContentResolver调用
 */
public class NotesProvider extends ContentProvider {
    /**
     * Uri匹配器，用于匹配不同的URI请求
     */
    private static final UriMatcher mMatcher;

    /**
     * 数据库帮助类实例
     */
    private NotesDatabaseHelper mHelper;

    /**
     * 日志标签
     */
    private static final String TAG = "NotesProvider";

    /**
     * URI类型：所有笔记
     */
    private static final int URI_NOTE            = 1;
    
    /**
     * URI类型：单条笔记
     */
    private static final int URI_NOTE_ITEM       = 2;
    
    /**
     * URI类型：所有数据
     */
    private static final int URI_DATA            = 3;
    
    /**
     * URI类型：单条数据
     */
    private static final int URI_DATA_ITEM       = 4;

    /**
     * URI类型：搜索
     */
    private static final int URI_SEARCH          = 5;
    
    /**
     * URI类型：搜索建议
     */
    private static final int URI_SEARCH_SUGGEST  = 6;

    /**
     * 静态初始化块，初始化UriMatcher
     */
    static {
        mMatcher = new UriMatcher(UriMatcher.NO_MATCH);
        // 添加URI匹配规则
        mMatcher.addURI(Notes.AUTHORITY, "note", URI_NOTE);           // content://micode_notes/note
        mMatcher.addURI(Notes.AUTHORITY, "note/#", URI_NOTE_ITEM);    // content://micode_notes/note/1
        mMatcher.addURI(Notes.AUTHORITY, "data", URI_DATA);           // content://micode_notes/data
        mMatcher.addURI(Notes.AUTHORITY, "data/#", URI_DATA_ITEM);    // content://micode_notes/data/1
        mMatcher.addURI(Notes.AUTHORITY, "search", URI_SEARCH);       // content://micode_notes/search
        mMatcher.addURI(Notes.AUTHORITY, SearchManager.SUGGEST_URI_PATH_QUERY, URI_SEARCH_SUGGEST); // 搜索建议
        mMatcher.addURI(Notes.AUTHORITY, SearchManager.SUGGEST_URI_PATH_QUERY + "/*", URI_SEARCH_SUGGEST); // 带参数的搜索建议
    }

    /**
     * 搜索结果投影定义：替换换行符并修剪空白，确保搜索结果显示完整信息
     */
    private static final String NOTES_SEARCH_PROJECTION = NoteColumns.ID + ","
        + NoteColumns.ID + " AS " + SearchManager.SUGGEST_COLUMN_INTENT_EXTRA_DATA + ","
        + "TRIM(REPLACE(" + NoteColumns.SNIPPET + ", x'0A','')) AS " + SearchManager.SUGGEST_COLUMN_TEXT_1 + ","
        + "TRIM(REPLACE(" + NoteColumns.SNIPPET + ", x'0A','')) AS " + SearchManager.SUGGEST_COLUMN_TEXT_2 + ","
        + R.drawable.search_result + " AS " + SearchManager.SUGGEST_COLUMN_ICON_1 + ","
        + "'" + Intent.ACTION_VIEW + "' AS " + SearchManager.SUGGEST_COLUMN_INTENT_ACTION + ","
        + "'" + Notes.TextNote.CONTENT_TYPE + "' AS " + SearchManager.SUGGEST_COLUMN_INTENT_DATA;

    /**
     * 笔记内容搜索查询语句 - 搜索标题和内容（通过JOIN连接NOTE和DATA表）
     */
    private static String NOTES_SNIPPET_SEARCH_QUERY = "SELECT DISTINCT " + NoteColumns.ID + ","
        + NoteColumns.ALERTED_DATE + ","
        + NoteColumns.BG_COLOR_ID + ","
        + NoteColumns.CREATED_DATE + ","
        + NoteColumns.HAS_ATTACHMENT + ","
        + NoteColumns.MODIFIED_DATE + ","
        + NoteColumns.NOTES_COUNT + ","
        + NoteColumns.PARENT_ID + ","
        + NoteColumns.SNIPPET + ","
        + NoteColumns.TYPE + ","
        + NoteColumns.WIDGET_ID + ","
        + NoteColumns.WIDGET_TYPE + ","
        + NoteColumns.PINNED
        + " FROM " + TABLE.NOTE
        + " LEFT JOIN " + TABLE.DATA + " ON " + NoteColumns.ID + "=" + TABLE.DATA + "." + net.micode.notes.data.Notes.DataColumns.NOTE_ID
        + " WHERE (" + NoteColumns.SNIPPET + " LIKE ? OR " + TABLE.DATA + "." + net.micode.notes.data.Notes.DataColumns.CONTENT + " LIKE ?)"
        + " AND " + NoteColumns.PARENT_ID + "<>" + Notes.ID_TRASH_FOLDER
        + " AND " + NoteColumns.TYPE + "=" + Notes.TYPE_NOTE;
    
    /**
     * 搜索建议查询语句
     */
    private static String NOTES_SEARCH_SUGGEST_QUERY = "SELECT DISTINCT " + NoteColumns.ID + ","
        + NoteColumns.ID + " AS " + SearchManager.SUGGEST_COLUMN_INTENT_EXTRA_DATA + ","
        + "TRIM(REPLACE(" + NoteColumns.SNIPPET + ", x'0A','')) AS " + SearchManager.SUGGEST_COLUMN_TEXT_1 + ","
        + "TRIM(REPLACE(" + NoteColumns.SNIPPET + ", x'0A','')) AS " + SearchManager.SUGGEST_COLUMN_TEXT_2 + ","
        + R.drawable.search_result + " AS " + SearchManager.SUGGEST_COLUMN_ICON_1 + ","
        + "'" + Intent.ACTION_VIEW + "' AS " + SearchManager.SUGGEST_COLUMN_INTENT_ACTION + ","
        + "'" + Notes.TextNote.CONTENT_TYPE + "' AS " + SearchManager.SUGGEST_COLUMN_INTENT_DATA
        + " FROM " + TABLE.NOTE
        + " WHERE " + NoteColumns.SNIPPET + " LIKE ?"
        + " AND " + NoteColumns.PARENT_ID + "<>" + Notes.ID_TRASH_FOLDER
        + " AND " + NoteColumns.TYPE + "=" + Notes.TYPE_NOTE;

    /**
     * 初始化ContentProvider
     * @return 是否初始化成功
     */
    @Override
    public boolean onCreate() {
        // 获取数据库帮助类实例
        mHelper = NotesDatabaseHelper.getInstance(getContext());
        return true;
    }

    /**
     * 查询数据
     * @param uri 查询的URI
     * @param projection 要查询的列
     * @param selection 查询条件
     * @param selectionArgs 查询条件参数
     * @param sortOrder 排序方式
     * @return 查询结果游标
     */
    @Override
    public Cursor query(Uri uri, String[] projection, String selection, String[] selectionArgs,
            String sortOrder) {
        Cursor c = null;
        SQLiteDatabase db = mHelper.getReadableDatabase();
        String id = null;
        switch (mMatcher.match(uri)) {
            case URI_NOTE:
                c = db.query(TABLE.NOTE, projection, selection, selectionArgs, null, null,
                        sortOrder);
                break;
            case URI_NOTE_ITEM:
                id = uri.getPathSegments().get(1);
                c = db.query(TABLE.NOTE, projection, NoteColumns.ID + "=" + id
                        + parseSelection(selection), selectionArgs, null, null, sortOrder);
                break;
            case URI_DATA:
                c = db.query(TABLE.DATA, projection, selection, selectionArgs, null, null,
                        sortOrder);
                break;
            case URI_DATA_ITEM:
                id = uri.getPathSegments().get(1);
                c = db.query(TABLE.DATA, projection, DataColumns.ID + "=" + id
                        + parseSelection(selection), selectionArgs, null, null, sortOrder);
                break;
            case URI_SEARCH:
            case URI_SEARCH_SUGGEST:
                if (sortOrder != null || projection != null) {
                    throw new IllegalArgumentException(
                            "do not specify sortOrder, selection, selectionArgs, or projection" + "with this query");
                }

                String searchString = null;
                if (mMatcher.match(uri) == URI_SEARCH_SUGGEST) {
                    if (uri.getPathSegments().size() > 1) {
                        searchString = uri.getPathSegments().get(1);
                    }
                } else {
                    searchString = uri.getQueryParameter("pattern");
                }

                if (TextUtils.isEmpty(searchString)) {
                    return null;
                }

                try {
                    searchString = String.format("%%%s%%", searchString);
                    if (mMatcher.match(uri) == URI_SEARCH_SUGGEST) {
                        // 搜索建议：返回搜索建议格式的结果
                        c = db.rawQuery(NOTES_SEARCH_SUGGEST_QUERY,
                                new String[] { searchString });
                    } else {
                        // 内容搜索：返回完整NoteItemData.PROJECTION列的结果
                        c = db.rawQuery(NOTES_SNIPPET_SEARCH_QUERY,
                                new String[] { searchString, searchString });
                    }
                } catch (IllegalStateException ex) {
                    Log.e(TAG, "got exception: " + ex.toString());
                }
                break;
            default:
                throw new IllegalArgumentException("Unknown URI " + uri);
        }
        if (c != null) {
            c.setNotificationUri(getContext().getContentResolver(), uri);
        }
        return c;
    }

    /**
     * 插入数据
     * @param uri 插入的URI
     * @param values 要插入的数据
     * @return 插入数据的URI
     */
    @Override
    public Uri insert(Uri uri, ContentValues values) {
        SQLiteDatabase db = mHelper.getWritableDatabase();
        long dataId = 0, noteId = 0, insertedId = 0;
        switch (mMatcher.match(uri)) {
            case URI_NOTE:
                insertedId = noteId = db.insert(TABLE.NOTE, null, values);
                break;
            case URI_DATA:
                if (values.containsKey(DataColumns.NOTE_ID)) {
                    noteId = values.getAsLong(DataColumns.NOTE_ID);
                } else {
                    Log.d(TAG, "Wrong data format without note id:" + values.toString());
                }
                insertedId = dataId = db.insert(TABLE.DATA, null, values);
                break;
            default:
                throw new IllegalArgumentException("Unknown URI " + uri);
        }
        // Notify the note uri
        if (noteId > 0) {
            getContext().getContentResolver().notifyChange(
                    ContentUris.withAppendedId(Notes.CONTENT_NOTE_URI, noteId), null);
        }

        // Notify the data uri
        if (dataId > 0) {
            getContext().getContentResolver().notifyChange(
                    ContentUris.withAppendedId(Notes.CONTENT_DATA_URI, dataId), null);
        }

        return ContentUris.withAppendedId(uri, insertedId);
    }

    /**
     * 删除数据
     * @param uri 删除的URI
     * @param selection 删除条件
     * @param selectionArgs 删除条件参数
     * @return 删除的行数
     */
    @Override
    public int delete(Uri uri, String selection, String[] selectionArgs) {
        int count = 0;
        String id = null;
        SQLiteDatabase db = mHelper.getWritableDatabase();
        boolean deleteData = false;
        switch (mMatcher.match(uri)) {
            case URI_NOTE:
                // 检查是否是彻底删除（selection包含回收站条件）
                boolean isPermanentDelete = selection != null && selection.contains(NoteColumns.PARENT_ID + "=" + Notes.ID_TRASH_FOLDER);
                if (isPermanentDelete) {
                    // 彻底删除回收站中的笔记
                    selection = "(" + selection + ") AND " + NoteColumns.ID + ">0 ";
                    count = db.delete(TABLE.NOTE, selection, selectionArgs);
                } else {
                    // 将笔记移动到回收站
                    ContentValues values = new ContentValues();
                    values.put(NoteColumns.PARENT_ID, Notes.ID_TRASH_FOLDER);
                    selection = "(" + selection + ") AND " + NoteColumns.ID + ">0 ";
                    count = db.update(TABLE.NOTE, values, selection, selectionArgs);
                }
                break;
            case URI_NOTE_ITEM:
                id = uri.getPathSegments().get(1);
                /**
                 * ID that smaller than 0 is system folder which is not allowed to
                 * trash
                 */
                long noteId = Long.valueOf(id);
                if (noteId <= 0) {
                    break;
                }
                // 检查是否是彻底删除
                boolean isItemPermanentDelete = selection != null && selection.contains(NoteColumns.PARENT_ID + "=" + Notes.ID_TRASH_FOLDER);
                if (isItemPermanentDelete) {
                    // 彻底删除单个笔记
                    count = db.delete(TABLE.NOTE,
                            NoteColumns.ID + "=" + id + parseSelection(selection), selectionArgs);
                } else {
                    // 将单个笔记移动到回收站
                    ContentValues values = new ContentValues();
                    values.put(NoteColumns.PARENT_ID, Notes.ID_TRASH_FOLDER);
                    count = db.update(TABLE.NOTE, values,
                            NoteColumns.ID + "=" + id + parseSelection(selection), selectionArgs);
                }
                break;
            case URI_DATA:
                count = db.delete(TABLE.DATA, selection, selectionArgs);
                deleteData = true;
                break;
            case URI_DATA_ITEM:
                id = uri.getPathSegments().get(1);
                count = db.delete(TABLE.DATA,
                        DataColumns.ID + "=" + id + parseSelection(selection), selectionArgs);
                deleteData = true;
                break;
            default:
                throw new IllegalArgumentException("Unknown URI " + uri);
        }

        if (count > 0) {
            if (deleteData) {
                getContext().getContentResolver().notifyChange(Notes.CONTENT_NOTE_URI, null);
            }
            getContext().getContentResolver().notifyChange(uri, null);
        }
        return count;
    }

    /**
     * 更新数据
     * @param uri 更新的URI
     * @param values 要更新的数据
     * @param selection 更新条件
     * @param selectionArgs 更新条件参数
     * @return 更新的行数
     */
    @Override
    public int update(Uri uri, ContentValues values, String selection, String[] selectionArgs) {
        int count = 0;
        String id = null;
        SQLiteDatabase db = mHelper.getWritableDatabase();
        boolean updateData = false;
        switch (mMatcher.match(uri)) {
            case URI_NOTE:
                increaseNoteVersion(-1, selection, selectionArgs);
                count = db.update(TABLE.NOTE, values, selection, selectionArgs);
                break;
            case URI_NOTE_ITEM:
                id = uri.getPathSegments().get(1);
                increaseNoteVersion(Long.valueOf(id), selection, selectionArgs);
                count = db.update(TABLE.NOTE, values, NoteColumns.ID + "=" + id
                        + parseSelection(selection), selectionArgs);
                break;
            case URI_DATA:
                count = db.update(TABLE.DATA, values, selection, selectionArgs);
                updateData = true;
                break;
            case URI_DATA_ITEM:
                id = uri.getPathSegments().get(1);
                count = db.update(TABLE.DATA, values, DataColumns.ID + "=" + id
                        + parseSelection(selection), selectionArgs);
                updateData = true;
                break;
            default:
                throw new IllegalArgumentException("Unknown URI " + uri);
        }

        if (count > 0) {
            if (updateData) {
                getContext().getContentResolver().notifyChange(Notes.CONTENT_NOTE_URI, null);
            }
            getContext().getContentResolver().notifyChange(uri, null);
        }
        return count;
    }

    /**
     * 解析查询条件
     * @param selection 查询条件
     * @return 解析后的查询条件
     */
    private String parseSelection(String selection) {
        return (!TextUtils.isEmpty(selection) ? " AND (" + selection + ')' : "");
    }

    /**
     * 增加笔记版本号
     * @param id 笔记ID
     * @param selection 查询条件
     * @param selectionArgs 查询条件参数
     */
    private void increaseNoteVersion(long id, String selection, String[] selectionArgs) {
        StringBuilder sql = new StringBuilder(120);
        sql.append("UPDATE ");
        sql.append(TABLE.NOTE);
        sql.append(" SET ");
        sql.append(NoteColumns.VERSION);
        sql.append("=" + NoteColumns.VERSION + "+1 ");

        if (id > 0 || !TextUtils.isEmpty(selection)) {
            sql.append(" WHERE ");
        }
        if (id > 0) {
            sql.append(NoteColumns.ID + "=" + String.valueOf(id));
        }
        if (!TextUtils.isEmpty(selection)) {
            String selectString = id > 0 ? parseSelection(selection) : selection;
            for (String args : selectionArgs) {
                selectString = selectString.replaceFirst("\\?", args);
            }
            sql.append(selectString);
        }

        mHelper.getWritableDatabase().execSQL(sql.toString());
    }

    /**
     * 获取MIME类型
     * @param uri URI
     * @return MIME类型
     */
    @Override
    public String getType(Uri uri) {
        // TODO Auto-generated method stub
        return null;
    }

}