WIP

server/src/lib/LogicEvaluation/Lexer.js

@@ -0,0 +1,172 @@
+
+const OperationType = {
+  LOGIC: 'LOGIC',
+  STRING: 'STRING',
+  COMPARISON: 'COMPARISON',
+  MATH: 'MATH',
+};
+
+export class Lexer {
+  // operation table
+  static get optable() {
+    return {
+      '=': OperationType.LOGIC,
+      '&': OperationType.LOGIC,
+      '|': OperationType.LOGIC,
+      '?': OperationType.LOGIC,
+      ':': OperationType.LOGIC,
+
+      '\'': OperationType.STRING,
+      '"': OperationType.STRING,
+
+      '!': OperationType.COMPARISON,
+      '>': OperationType.COMPARISON,
+      '<': OperationType.COMPARISON,
+
+      '(': OperationType.MATH,
+      ')': OperationType.MATH,
+      '+': OperationType.MATH,
+      '-': OperationType.MATH,
+      '*': OperationType.MATH,
+      '/': OperationType.MATH,
+      '%': OperationType.MATH,
+    };
+  }
+
+  /**
+   * Constructor
+   * @param {*} expression -
+   */
+  constructor(expression) {
+    this.currentIndex = 0;
+    this.input = expression;
+    this.tokenList = [];
+  }
+
+  getTokens() {
+    let tok;
+    do {
+      // read current token, so step should be -1
+      tok = this.pickNext(-1);
+      const pos = this.currentIndex;
+      switch (Lexer.optable[tok]) {
+        case OperationType.LOGIC:
+          // == && || ===
+          this.readLogicOpt(tok);
+          break;
+
+        case OperationType.STRING:
+          this.readString(tok);
+          break;
+
+        case OperationType.COMPARISON:
+          this.readCompare(tok);
+          break;
+
+        case OperationType.MATH:
+          this.receiveToken();
+          break;
+
+        default:
+          this.readValue(tok);
+      }
+
+      // if the pos not changed, this loop will go into a infinite loop, every step of while loop,
+      // we must move the pos forward
+      // so here we should throw error, for example `1 & 2`
+      if (pos === this.currentIndex && tok !== undefined) {
+        const err = new Error(`unkonw token ${tok} from input string ${this.input}`);
+        err.name = 'UnknowToken';
+        throw err;
+      }
+    } while (tok !== undefined)
+
+    return this.tokenList;
+  }
+
+  /**
+   * read next token, the index param can set next step, default go foward 1 step
+   *
+   * @param index next postion
+   */
+  pickNext(index = 0) {
+    return this.input[index + this.currentIndex + 1];
+  }
+
+  /**
+   * Store token into result tokenList, and move the pos index
+   *
+   * @param index
+   */
+  receiveToken(index = 1) {
+    const tok = this.input.slice(this.currentIndex, this.currentIndex + index).trim();
+    // skip empty string
+    if (tok) {
+      this.tokenList.push(tok);
+    }
+
+    this.currentIndex += index;
+  }
+
+  // ' or "
+  readString(tok) {
+    let next;
+    let index = 0;
+    do {
+      next = this.pickNext(index);
+      index += 1;
+    } while (next !== tok && next !== undefined);
+    this.receiveToken(index + 1);
+  }
+
+  // > or < or >= or <= or !==
+  // tok in (>, <, !)
+  readCompare(tok) {
+    if (this.pickNext() !== '=') {
+      this.receiveToken(1);
+      return;
+    }
+    // !==
+    if (tok === '!' && this.pickNext(1) === '=') {
+      this.receiveToken(3);
+      return;
+    }
+    this.receiveToken(2);
+  }
+
+  // === or ==
+  // && ||
+  readLogicOpt(tok) {
+    if (this.pickNext() === tok) {
+      // ===
+      if (tok === '=' && this.pickNext(1) === tok) {
+        return this.receiveToken(3);
+      }
+      // == && ||
+      return this.receiveToken(2);
+    }
+    // handle as &&
+    // a ? b : c is equal to a && b || c
+    if (tok === '?' || tok === ':') {
+      return this.receiveToken(1);
+    }
+  }
+
+  readValue(tok) {
+    if (!tok) {
+      return;
+    }
+
+    let index = 0;
+    while (!Lexer.optable[tok] && tok !== undefined) {
+      tok = this.pickNext(index);
+      index += 1;
+    }
+    this.receiveToken(index);
+  }
+}
+
+export default function token(expression) {
+  const lexer = new Lexer(expression);
+  return lexer.getTokens();
+}

server/src/lib/LogicEvaluation/Parser.js

@@ -0,0 +1,159 @@
+export const OPERATION = {
+  '!': 5,
+  '*': 4,
+  '/': 4,
+  '%': 4,
+  '+': 3,
+  '-': 3,
+  '>': 2,
+  '<': 2,
+  '>=': 2,
+  '<=': 2,
+  '===': 2,
+  '!==': 2,
+  '==': 2,
+  '!=': 2,
+  '&&': 1,
+  '||': 1,
+  '?': 1,
+  ':': 1,
+};
+
+// export interface Node {
+//   left: Node | string | null;
+//   right: Node | string | null;
+//   operation: string;
+//   grouped?: boolean;
+// };
+
+export default class Parser {
+
+  constructor(token) {
+    this.index = -1;
+    this.blockLevel = 0;
+    this.token = token;
+  }
+
+  /**
+   * 
+   * @return {Node | string} =- 
+   */
+  parse() {
+    let tok;
+    let root = {
+      left: null,
+      right: null,
+      operation: null,
+    };
+
+    do {
+      tok = this.parseStatement();
+
+      if (tok === null || tok === undefined) {
+        break;
+      }
+
+      if (root.left === null) {
+        root.left = tok;
+        root.operation = this.nextToken();
+
+        if (!root.operation) {
+          return tok;
+        }
+
+        root.right = this.parseStatement();
+      } else {
+        if (typeof tok !== 'string') {
+          throw new Error('operation must be string, but get ' + JSON.stringify(tok));
+        }
+        root = this.addNode(tok, this.parseStatement(), root);
+      }
+    } while (tok);
+
+    return root;
+  }
+
+  nextToken() {
+    this.index += 1;
+    return this.token[this.index];
+  }
+
+  prevToken() {
+    return this.token[this.index - 1];
+  }
+
+  /**
+   * 
+   * @param {string} operation 
+   * @param {Node|String|null} right 
+   * @param {Node} root 
+   */
+  addNode(operation, right, root) {
+    let pre = root;
+    
+    if (this.compare(pre.operation, operation) < 0 && !pre.grouped) {
+      
+      while (pre.right !== null &&
+        typeof pre.right !== 'string' &&
+        this.compare(pre.right.operation, operation) < 0 && !pre.right.grouped) {
+        pre = pre.right;
+      }
+
+      pre.right = {
+        operation,
+        left: pre.right,
+        right,
+      };
+      return root;
+    }
+    return {
+      left: pre,
+      right,
+      operation,
+    }
+  }
+
+  /**
+   * 
+   * @param {String} a 
+   * @param {String} b 
+   */
+  compare(a, b) {
+    if (!OPERATION.hasOwnProperty(a) || !OPERATION.hasOwnProperty(b)) {
+      throw new Error(`unknow operation ${a} or ${b}`);
+    }
+    return OPERATION[a] - OPERATION[b];
+  }
+
+  /**
+   * @return string | Node | null
+   */
+  parseStatement() {
+    const token = this.nextToken();
+    if (token === '(') {
+      this.blockLevel += 1;
+      const node = this.parse();
+      this.blockLevel -= 1;
+
+      if (typeof node !== 'string') {
+        node.grouped = true;
+      }
+      return node;
+    }
+
+    if (token === ')') {
+      return null;
+    }
+
+    if (token === '!') {
+      return { left: null, operation: token, right: this.parseStatement() }
+    }
+
+    // 3 > -12 or -12 + 10
+    if (token === '-' && (OPERATION[this.prevToken()] > 0 || this.prevToken() === undefined)) {
+      return { left: '0', operation: token, right: this.parseStatement(), grouped: true };
+    }
+
+    return token;
+  }
+}

server/src/lib/LogicEvaluation/QueryParser.js

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+import { OPERATION } from './Parser';
+
+export default class QueryParser {
+
+  constructor(tree, queries) {
+    this.tree = tree;
+    this.queries = queries;
+    this.query = null;
+  }
+
+  setQuery(query) {
+    this.query = query.clone();
+  }
+
+  parse() {
+    return this.parseNode(this.tree);
+  }
+
+  parseNode(node) {
+    if (typeof node === 'string') {
+      const nodeQuery = this.getQuery(node);
+      return (query) => { nodeQuery(query); };
+    }
+    if (OPERATION[node.operation] === undefined) {
+      throw new Error(`unknow expression ${node.operation}`);
+    }
+    const leftQuery = this.getQuery(node.left);
+    const rightQuery = this.getQuery(node.right);
+
+    switch (node.operation) {
+      case '&&':
+      case 'AND':
+      default:
+        return (nodeQuery) => nodeQuery.where((query) => {
+          query.where((q) => { leftQuery(q); });
+          query.andWhere((q) => { rightQuery(q); });
+        });
+      case '||':
+      case 'OR':
+        return (nodeQuery) => nodeQuery.where((query) => {
+          query.where((q) => { leftQuery(q); });
+          query.orWhere((q) => { rightQuery(q); });
+        });
+    }
+  }
+
+  getQuery(node) {
+    if (typeof node !== 'string' && node !== null) {
+      return this.parseNode(node);
+    }
+    const value = parseFloat(node);
+
+    if (!isNaN(value)) {
+      if (typeof this.queries[node] === 'undefined') {
+        throw new Error(`unknow query under index ${node}`);
+      }
+      return this.queries[node];
+    }
+    return null;
+  }
+}

server/src/lib/ViewRolesBuilder/index.js

@@ -0,0 +1,89 @@
+import { difference } from 'lodash';
+import { Lexer } from '@/lib/LogicEvaluation/Lexer';
+import Parser from '@/lib/LogicEvaluation/Parser';
+import QueryParser from '@/lib/LogicEvaluation/QueryParser';
+import resourceFieldsKeys from '@/data/ResourceFieldsKeys';
+
+//  const role = {
+//   compatotor: '',
+//   value: '',
+//   columnKey: '',
+//   columnSlug: '',
+//   index: 1,
+// }
+
+export function buildRoleQuery(role) {
+  const columnName = resourceFieldsKeys[role.columnKey];
+
+  switch (role.comparator) {
+    case 'equals':
+    default:
+      return (builder) => {
+        builder.where(columnName, role.value);
+      };
+    case 'not_equal':
+    case 'not_equals':
+      return (builder) => {
+        builder.whereNot(columnName, role.value);
+      };
+  }
+}
+
+/**
+ * Builds database query from stored view roles.
+ *
+ * @param {Array} roles -
+ * @return {Function}
+ */
+export function viewRolesBuilder(roles, logicExpression = '') {
+  const rolesIndexSet = {};
+
+  roles.forEach((role) => {
+    rolesIndexSet[role.index] = buildRoleQuery(role);
+  });
+  // Lexer for logic expression.
+  const lexer = new Lexer(logicExpression);
+  const tokens = lexer.getTokens();
+
+  // Parse the logic expression.
+  const parser = new Parser(tokens);
+  const parsedTree = parser.parse();
+
+  const queryParser = new QueryParser(parsedTree, rolesIndexSet);
+  return queryParser.parse();
+}
+
+/**
+ * Validates the view logic expression.
+ * @param {String} logicExpression 
+ * @param {Array} indexes 
+ */
+export function validateViewLogicExpression(logicExpression, indexes) {
+  const logicExpIndexes = logicExpression.match(/\d+/g) || [];
+  return !difference(logicExpIndexes.map(Number), indexes).length;
+}
+
+/**
+ * 
+ * @param {Array} roles -
+ * @param {String} logicExpression -
+ * @return {Boolean}
+ */
+export function validateViewRoles(roles, logicExpression) {
+  return validateViewLogicExpression(logicExpression, roles.map((r) => r.index));
+}
+
+/**
+ * Mapes the view roles to view conditionals.
+ * @param {Array} viewRoles -
+ * @return {Array}
+ */
+export function mapViewRolesToConditionals(viewRoles) {
+  return viewRoles.map((viewRole) => ({
+    comparator: viewRole.comparator,
+    value: viewRole.value,
+    columnKey: viewRole.field.columnKey,
+    slug: viewRole.field.slug,
+    index: viewRole.index,
+  }));
+}