Update to NPM version

ProjectSourceCode/node_modules/pg-promise/lib/tx-mode.js

@@ -0,0 +1,190 @@
+/*
+ * Copyright (c) 2015-present, Vitaly Tomilov
+ *
+ * See the LICENSE file at the top-level directory of this distribution
+ * for licensing information.
+ *
+ * Removal or modification of this copyright notice is prohibited.
+ */
+
+const {InnerState} = require(`./inner-state`);
+const {addInspection} = require(`./utils`);
+const {assert} = require(`./assert`);
+
+/**
+ * @enum {number}
+ * @alias txMode.isolationLevel
+ * @readonly
+ * @summary Transaction Isolation Level.
+ * @description
+ * The type is available from the {@link txMode} namespace.
+ *
+ * @see $[Transaction Isolation]
+ */
+const isolationLevel = {
+    /** Isolation level not specified. */
+    none: 0,
+
+    /** ISOLATION LEVEL SERIALIZABLE */
+    serializable: 1,
+
+    /** ISOLATION LEVEL REPEATABLE READ */
+    repeatableRead: 2,
+
+    /** ISOLATION LEVEL READ COMMITTED */
+    readCommitted: 3
+
+    // From the official documentation: http://www.postgresql.org/docs/9.5/static/sql-set-transaction.html
+    // The SQL standard defines one additional level, READ UNCOMMITTED. In PostgreSQL READ UNCOMMITTED is treated as READ COMMITTED.
+    // => skipping `READ UNCOMMITTED`.
+};
+
+/**
+ * @class txMode.TransactionMode
+ * @description
+ * Constructs a complete transaction-opening `BEGIN` command, from these options:
+ *  - isolation level
+ *  - access mode
+ *  - deferrable mode
+ *
+ * The type is available from the {@link txMode} namespace.
+ *
+ * @param {} [options]
+ * Transaction Mode options.
+ *
+ * @param {txMode.isolationLevel} [options.tiLevel]
+ * Transaction Isolation Level.
+ *
+ * @param {boolean} [options.readOnly]
+ * Sets transaction access mode based on the read-only flag:
+ *  - `undefined` - access mode not specified (default)
+ *  - `true` - access mode is set to `READ ONLY`
+ *  - `false` - access mode is set to `READ WRITE`
+ *
+ * @param {boolean} [options.deferrable]
+ * Sets transaction deferrable mode based on the boolean value:
+ *  - `undefined` - deferrable mode not specified (default)
+ *  - `true` - mode is set to `DEFERRABLE`
+ *  - `false` - mode is set to `NOT DEFERRABLE`
+ *
+ * It is used only when `tiLevel`=`isolationLevel.serializable`
+ * and `readOnly`=`true`, or else it is ignored.
+ *
+ * @returns {txMode.TransactionMode}
+ *
+ * @see $[BEGIN], {@link txMode.isolationLevel}
+ *
+ * @example
+ *
+ * const {TransactionMode, isolationLevel} = pgp.txMode;
+ *
+ * // Create a reusable transaction mode (serializable + read-only + deferrable):
+ * const mode = new TransactionMode({
+ *     tiLevel: isolationLevel.serializable,
+ *     readOnly: true,
+ *     deferrable: true
+ * });
+ *
+ * db.tx({mode}, t => {
+ *     return t.any('SELECT * FROM table');
+ * })
+ *     .then(data => {
+ *         // success;
+ *     })
+ *     .catch(error => {
+ *         // error
+ *     });
+ *
+ * // Instead of the default BEGIN, such transaction will start with:
+ *
+ * // BEGIN ISOLATION LEVEL SERIALIZABLE READ ONLY DEFERRABLE
+ *
+ */
+class TransactionMode extends InnerState {
+
+    constructor(options) {
+        options = assert(options, [`tiLevel`, `deferrable`, `readOnly`]);
+        const {readOnly, deferrable} = options;
+        let {tiLevel} = options;
+        let level, accessMode, deferrableMode, begin = `begin`;
+        tiLevel = (tiLevel > 0) ? parseInt(tiLevel) : 0;
+
+        if (tiLevel > 0 && tiLevel < 4) {
+            const values = [`serializable`, `repeatable read`, `read committed`];
+            level = `isolation level ` + values[tiLevel - 1];
+        }
+        if (readOnly) {
+            accessMode = `read only`;
+        } else {
+            if (readOnly !== undefined) {
+                accessMode = `read write`;
+            }
+        }
+        // From the official documentation: http://www.postgresql.org/docs/9.5/static/sql-set-transaction.html
+        // The DEFERRABLE transaction property has no effect unless the transaction is also SERIALIZABLE and READ ONLY
+        if (tiLevel === isolationLevel.serializable && readOnly) {
+            if (deferrable) {
+                deferrableMode = `deferrable`;
+            } else {
+                if (deferrable !== undefined) {
+                    deferrableMode = `not deferrable`;
+                }
+            }
+        }
+        if (level) {
+            begin += ` ` + level;
+        }
+        if (accessMode) {
+            begin += ` ` + accessMode;
+        }
+        if (deferrableMode) {
+            begin += ` ` + deferrableMode;
+        }
+
+        super({begin, capBegin: begin.toUpperCase()});
+    }
+
+    /**
+     * @method txMode.TransactionMode#begin
+     * @description
+     * Returns a complete BEGIN statement, according to all the parameters passed into the class.
+     *
+     * This method is primarily for internal use by the library.
+     *
+     * @param {boolean} [cap=false]
+     * Indicates whether the returned SQL must be capitalized.
+     *
+     * @returns {string}
+     */
+    begin(cap) {
+        return cap ? this._inner.capBegin : this._inner.begin;
+    }
+}
+
+addInspection(TransactionMode, function () {
+    return this.begin(true);
+});
+
+/**
+ * @namespace txMode
+ * @description
+ * Transaction Mode namespace, available as `pgp.txMode`, before and after initializing the library.
+ *
+ * Extends the default `BEGIN` with Transaction Mode parameters:
+ *  - isolation level
+ *  - access mode
+ *  - deferrable mode
+ *
+ * @property {function} TransactionMode
+ * {@link txMode.TransactionMode TransactionMode} class constructor.
+ *
+ * @property {txMode.isolationLevel} isolationLevel
+ * Transaction Isolation Level enumerator
+ *
+ * @see $[BEGIN]
+ */
+module.exports = {
+    isolationLevel,
+    TransactionMode
+};
+