You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
138 lines
3.3 KiB
138 lines
3.3 KiB
import { Result } from "./result.mjs"; |
|
import { PawSQLiteError } from "./pawsqlite_error.mjs"; |
|
|
|
|
|
export class Transaction { |
|
constructor(dbName, adapter, enqueue, rollbackOnError=false) { |
|
this.dbName = dbName; |
|
this.adapter = adapter; |
|
this._rollbackOnError = rollbackOnError; |
|
|
|
this._enqueue = enqueue; |
|
this._completeCb = null; |
|
|
|
this._readyWait = null; |
|
this._ready = false; |
|
this._finalized = false; |
|
} |
|
|
|
async sql(sql, ...args) { |
|
if (this._finalized) { |
|
throw new PawSQLiteError("Transaction has already completed"); |
|
} |
|
|
|
if (!this._ready) { |
|
await this._waitUntilReady(); |
|
} |
|
|
|
try { |
|
return await this._executeSQL(sql, ...args); |
|
} catch (e) { |
|
if (this._rollbackOnError) { |
|
await this.rollback(); |
|
} |
|
throw e; |
|
} |
|
} |
|
|
|
// Allow for slightly more complex parameter substitution. |
|
// Instances of "???" will be replaced by the same number of comma-separated |
|
// question marks as items in the corresponding nested parateter array |
|
// eg. buildQuery("SELECT (???) FROM ?", [["col1", "col2"], "table1"]) |
|
// would output: ["SELECT (?, ?) FROM ?", ["col1", "col2", "table1"]] |
|
buildQuery(sql, ...args) { |
|
const parts = sql.split("???"); |
|
const subParamLengths = args |
|
.filter(Array.isArray) |
|
.map((a) => a.length); |
|
if (parts.length !== subParamLengths.length + 1) { |
|
throw new PawSQLiteError("Unable to build query: sub-" + |
|
"paramters do not match sub-paramters in query"); |
|
} |
|
|
|
const newQuery = parts.reduce((p1, p2, i) => { |
|
const length = subParamLengths[i - 1]; |
|
return p1 + new Array(length).fill("?").join(", ") + p2; |
|
}); |
|
|
|
const flatParams = args.reduce((acc, v) => { |
|
if (Array.isArray(v)) { |
|
Array.prototype.push.apply(acc, v); |
|
} else { |
|
acc.push(v); |
|
} |
|
return acc; |
|
}, []); |
|
|
|
return [newQuery, ...flatParams]; |
|
} |
|
|
|
commit() { |
|
return this._complete("COMMIT"); |
|
} |
|
|
|
rollback() { |
|
return this._complete("ROLLBACK"); |
|
} |
|
|
|
async _waitUntilReady() { |
|
if (!this._readyWait) { |
|
this._readyWait = (async () => { |
|
this._completeCb = await this._enqueue(); |
|
await this._begin(); |
|
this._ready = true; |
|
})(); |
|
} |
|
|
|
await this._readyWait; |
|
} |
|
|
|
async _executeSQL(sql, ...args) { |
|
const reg = /^\s*(BEGIN|END|COMMIT|ROLLBACK)(?:[^A-Z]|$)/i; |
|
const match = reg.exec(sql); |
|
if (match) { |
|
const statement = match[1].toUpperCase(); |
|
throw new PawSQLiteError("Manually managing transactions is " + |
|
"forbidden. Found: \"" + statement + "\" statement."); |
|
} |
|
|
|
const result = await this.adapter.sql(this.dbName, |
|
...this.buildQuery(sql, ...args)); |
|
|
|
return new Result(result); |
|
} |
|
|
|
async _begin() { |
|
const result = await this.adapter.sql(this.dbName, "BEGIN"); |
|
} |
|
|
|
async _complete(sql) { |
|
if (this._finalized) { |
|
throw new PawSQLiteError("Transaction has already completed"); |
|
} |
|
this._finalized = true; |
|
|
|
if (!this._readyWait) { |
|
// Transaction was unused |
|
return; |
|
} else if (!this._ready) { |
|
await this._waitUntilReady(); |
|
} |
|
|
|
let result; |
|
let error; |
|
try { |
|
result = await this.adapter.sql(this.dbName, sql); |
|
} catch (e) { |
|
error = e; |
|
} |
|
|
|
this._completeCb(); |
|
|
|
if (error) { |
|
throw error; |
|
} |
|
|
|
return new Result(result); |
|
} |
|
} |