171 lines
4.8 KiB
JavaScript
171 lines
4.8 KiB
JavaScript
var FILE_SYSTEM_NAME = require('../constants.js').FILE_SYSTEM_NAME;
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var FILE_STORE_NAME = require('../constants.js').FILE_STORE_NAME;
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var WSQL_VERSION = require('../constants.js').WSQL_VERSION;
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var WSQL_SIZE = require('../constants.js').WSQL_SIZE;
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var WSQL_DESC = require('../constants.js').WSQL_DESC;
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var Errors = require('../errors.js');
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var base64ArrayBuffer = require('base64-arraybuffer');
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function WebSQLContext(db, isReadOnly) {
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var that = this;
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this.getTransaction = function(callback) {
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if(that.transaction) {
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callback(that.transaction);
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return;
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}
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// Either do readTransaction() (read-only) or transaction() (read/write)
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db[isReadOnly ? 'readTransaction' : 'transaction'](function(transaction) {
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that.transaction = transaction;
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callback(transaction);
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});
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};
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}
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WebSQLContext.prototype.clear = function(callback) {
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function onError(transaction, error) {
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callback(error);
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}
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function onSuccess() {
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callback(null);
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}
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this.getTransaction(function(transaction) {
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transaction.executeSql('DELETE FROM ' + FILE_STORE_NAME + ';',
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[], onSuccess, onError);
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});
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};
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function _get(getTransaction, key, callback) {
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function onSuccess(transaction, result) {
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// If the key isn't found, return null
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var value = result.rows.length === 0 ? null : result.rows.item(0).data;
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callback(null, value);
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}
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function onError(transaction, error) {
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callback(error);
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}
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getTransaction(function(transaction) {
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transaction.executeSql('SELECT data FROM ' + FILE_STORE_NAME + ' WHERE id = ? LIMIT 1;',
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[key], onSuccess, onError);
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});
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}
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WebSQLContext.prototype.getObject = function(key, callback) {
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_get(this.getTransaction, key, function(err, result) {
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if(err) {
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return callback(err);
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}
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try {
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if(result) {
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result = JSON.parse(result);
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}
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} catch(e) {
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return callback(e);
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}
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callback(null, result);
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});
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};
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WebSQLContext.prototype.getBuffer = function(key, callback) {
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_get(this.getTransaction, key, function(err, result) {
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if(err) {
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return callback(err);
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}
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// Deal with zero-length ArrayBuffers, which will be encoded as ''
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if(result || result === '') {
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var arrayBuffer = base64ArrayBuffer.decode(result);
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result = Buffer.from(arrayBuffer);
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}
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callback(null, result);
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});
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};
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function _put(getTransaction, key, value, callback) {
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function onSuccess() {
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callback(null);
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}
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function onError(transaction, error) {
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callback(error);
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}
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getTransaction(function(transaction) {
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transaction.executeSql('INSERT OR REPLACE INTO ' + FILE_STORE_NAME + ' (id, data) VALUES (?, ?);',
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[key, value], onSuccess, onError);
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});
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}
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WebSQLContext.prototype.putObject = function(key, value, callback) {
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var json = JSON.stringify(value);
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_put(this.getTransaction, key, json, callback);
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};
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WebSQLContext.prototype.putBuffer = function(key, uint8BackedBuffer, callback) {
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var base64 = base64ArrayBuffer.encode(uint8BackedBuffer.buffer);
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_put(this.getTransaction, key, base64, callback);
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};
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WebSQLContext.prototype.delete = function(key, callback) {
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function onSuccess() {
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callback(null);
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}
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function onError(transaction, error) {
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callback(error);
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}
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this.getTransaction(function(transaction) {
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transaction.executeSql('DELETE FROM ' + FILE_STORE_NAME + ' WHERE id = ?;',
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[key], onSuccess, onError);
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});
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};
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function WebSQL(name) {
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this.name = name || FILE_SYSTEM_NAME;
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this.db = null;
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}
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WebSQL.isSupported = function() {
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return !!global.openDatabase;
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};
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WebSQL.prototype.open = function(callback) {
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var that = this;
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// Bail if we already have a db open
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if(that.db) {
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return callback();
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}
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var db = global.openDatabase(that.name, WSQL_VERSION, WSQL_DESC, WSQL_SIZE);
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if(!db) {
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callback('[WebSQL] Unable to open database.');
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return;
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}
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function onError(transaction, error) {
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if (error.code === 5) {
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callback(new Errors.EINVAL('WebSQL cannot be accessed. If private browsing is enabled, disable it.'));
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}
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callback(error);
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}
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function onSuccess() {
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that.db = db;
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callback();
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}
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// Create the table and index we'll need to store the fs data.
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db.transaction(function(transaction) {
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function createIndex(transaction) {
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transaction.executeSql('CREATE INDEX IF NOT EXISTS idx_' + FILE_STORE_NAME + '_id' +
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' on ' + FILE_STORE_NAME + ' (id);',
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[], onSuccess, onError);
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}
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transaction.executeSql('CREATE TABLE IF NOT EXISTS ' + FILE_STORE_NAME + ' (id unique, data TEXT);',
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[], createIndex, onError);
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});
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};
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WebSQL.prototype.getReadOnlyContext = function() {
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return new WebSQLContext(this.db, true);
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};
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WebSQL.prototype.getReadWriteContext = function() {
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return new WebSQLContext(this.db, false);
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};
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module.exports = WebSQL;
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