Files
genieacs/lib/common/expression/parser.ts
T
Zaid Humaimidi 3169e829e7 Refactor expression to Mongo query translation
The previous approach was simplistic and could result in inefficient queries
in certain edge cases, notably causing MongoDB to not utilize existing indexes
when querying by last inform timestamps given upper and lower bounds. The new
implementation leverages our existing expression minimizer code and can
therefore generate more efficient queries or at least queries that can take
advantage of existing indexes.
2023-08-09 19:48:49 -07:00

479 lines
13 KiB
TypeScript

/**
* Copyright 2013-2019 GenieACS Inc.
*
* This file is part of GenieACS.
*
* GenieACS is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License as
* published by the Free Software Foundation, either version 3 of the
* License, or (at your option) any later version.
*
* GenieACS is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with GenieACS. If not, see <http://www.gnu.org/licenses/>.
*/
import parsimmon from "parsimmon";
import { Expression } from "../../types";
// Turn escaped characters into real ones (e.g. "\\n" becomes "\n").
function interpretEscapes(str): string {
const escapes = {
b: "\b",
f: "\f",
n: "\n",
r: "\r",
t: "\t",
};
return str.replace(/\\(u[0-9a-fA-F]{4}|[^u])/g, (_, escape) => {
const type = escape.charAt(0);
const hex = escape.slice(1);
if (type === "u") return String.fromCharCode(parseInt(hex, 16));
if (escapes.hasOwnProperty(type)) return escapes[type];
return type;
});
}
export function map<T>(exp: Expression, callback: (e: Expression) => T): T {
if (!Array.isArray(exp)) return callback(exp);
let clone;
for (let i = 1; i < exp.length; ++i) {
const sub = map(exp[i], callback);
if (sub !== exp[i]) {
clone = clone || exp.slice();
clone[i] = sub;
}
}
return callback(clone || exp);
}
export async function mapAsync(
exp: Expression,
callback: (e: Expression) => Promise<Expression>
): Promise<Expression> {
if (!Array.isArray(exp)) return callback(exp);
let clone;
for (let i = 1; i < exp.length; ++i) {
const sub = await mapAsync(exp[i], callback);
if (sub !== exp[i]) {
clone = clone || exp.slice();
clone[i] = sub;
}
}
return callback(clone || exp);
}
function binaryLeft(
operatorsParser: parsimmon.Parser<string>,
nextParser: parsimmon.Parser<Expression>
): parsimmon.Parser<Expression> {
return parsimmon.seqMap(
nextParser,
parsimmon.seq(operatorsParser, nextParser).many(),
(first, rest) =>
rest.reduce((acc, ch) => {
const [op, another] = ch;
if (Array.isArray(acc) && op === acc[0]) return acc.concat([another]);
return [op, acc, another];
}, first)
);
}
const lang = parsimmon.createLanguage({
ComparisonOperator: function () {
return parsimmon
.alt(
parsimmon.string(">="),
parsimmon.string("<>"),
parsimmon.string("<="),
parsimmon.string("="),
parsimmon.string(">"),
parsimmon.string("<")
)
.skip(parsimmon.optWhitespace);
},
LikeOperator: function () {
return parsimmon
.alt(
parsimmon.regexp(/like/i).result("LIKE").desc("LIKE"),
parsimmon
.regexp(/not\s+like/i)
.result("NOT LIKE")
.desc("NOT LIKE")
)
.notFollowedBy(parsimmon.regexp(/[a-zA-Z0-9_]/))
.skip(parsimmon.optWhitespace);
},
IsNullOperator: function () {
return parsimmon
.alt(
parsimmon
.regexp(/is\s+null/i)
.result("IS NULL")
.desc("IS NULL"),
parsimmon
.regexp(/is\s+not\s+null/i)
.result("IS NOT NULL")
.desc("IS NOT NULL")
)
.notFollowedBy(parsimmon.regexp(/[a-zA-Z0-9_]/))
.skip(parsimmon.optWhitespace);
},
NotOperator: function () {
return parsimmon
.regexp(/not/i)
.result("NOT")
.notFollowedBy(parsimmon.regexp(/[a-zA-Z0-9_]/))
.skip(parsimmon.optWhitespace)
.desc("NOT");
},
AndOperator: function () {
return parsimmon
.regexp(/and/i)
.result("AND")
.notFollowedBy(parsimmon.regexp(/[a-zA-Z0-9_]/))
.skip(parsimmon.optWhitespace)
.desc("AND");
},
OrOperator: function () {
return parsimmon
.regexp(/or/i)
.result("OR")
.notFollowedBy(parsimmon.regexp(/[a-zA-Z0-9_]/))
.skip(parsimmon.optWhitespace)
.desc("OR");
},
Parameter: function (r) {
return parsimmon
.alt(
parsimmon.regexp(/[a-zA-Z0-9_.*-]+/),
r.Expression.wrap(
parsimmon.string("{").skip(parsimmon.optWhitespace),
parsimmon.string("}")
)
)
.atLeast(1)
.map((x) => ["PARAM", x.length > 1 ? ["||"].concat(x) : x[0]])
.skip(parsimmon.optWhitespace)
.desc("parameter");
},
StringValueSql: function () {
return parsimmon
.regexp(/'([^']*)'/, 1)
.atLeast(1)
.skip(parsimmon.optWhitespace)
.map((s) => s.join("'"))
.desc("string");
},
StringValueJs: function () {
return parsimmon
.regexp(/"((?:\\.|.)*?)"/, 1)
.skip(parsimmon.optWhitespace)
.map(interpretEscapes)
.desc("string");
},
NumberValue: function () {
return parsimmon
.regexp(/-?(0|[1-9][0-9]*)([.][0-9]+)?([eE][+-]?[0-9]+)?/)
.notFollowedBy(parsimmon.regexp(/[a-zA-Z0-9_]/))
.skip(parsimmon.optWhitespace)
.map(Number)
.desc("number");
},
BooleanValue: function () {
return parsimmon
.alt(
parsimmon.regexp(/true/i).result(true).desc("TRUE"),
parsimmon.regexp(/false/i).result(false).desc("FALSE")
)
.notFollowedBy(parsimmon.regexp(/[a-zA-Z0-9_]/))
.skip(parsimmon.optWhitespace);
},
NullValue: function () {
return parsimmon
.regexp(/null/i)
.notFollowedBy(parsimmon.regexp(/[a-zA-Z0-9_]/))
.skip(parsimmon.optWhitespace)
.result(null)
.desc("NULL");
},
FuncValue: function (r) {
return parsimmon.seqMap(
parsimmon
.regexp(/([a-zA-Z0-9_]+)/, 1)
.skip(parsimmon.optWhitespace)
.desc("function"),
r.ExpressionList.wrap(
parsimmon.string("(").skip(parsimmon.optWhitespace),
parsimmon.string(")").skip(parsimmon.optWhitespace)
),
(f, args) => ["FUNC", f.toUpperCase()].concat(args)
);
},
WhenPair: function (r) {
return parsimmon.seq(
parsimmon
.regexp(/when/i)
.notFollowedBy(parsimmon.regexp(/[a-zA-Z0-9_]/))
.skip(parsimmon.optWhitespace)
.desc("WHEN")
.then(r.Expression),
parsimmon
.regexp(/then/i)
.notFollowedBy(parsimmon.regexp(/[a-zA-Z0-9_]/))
.skip(parsimmon.optWhitespace)
.desc("THEN")
.then(r.Expression)
);
},
CaseStatement: function (r) {
return parsimmon.seqMap(
parsimmon
.regexp(/case/i)
.result("CASE")
.notFollowedBy(parsimmon.regexp(/[a-zA-Z0-9_]/))
.skip(parsimmon.optWhitespace)
.desc("CASE"),
r.WhenPair.many(),
parsimmon
.regexp(/else/i)
.notFollowedBy(parsimmon.regexp(/[a-zA-Z0-9_]/))
.skip(parsimmon.optWhitespace)
.desc("ELSE")
.then(r.Expression)
.map((e) => [[true, e]])
.fallback(null)
.skip(
parsimmon
.regex(/end/i)
.notFollowedBy(parsimmon.regexp(/[a-zA-Z0-9_]/))
)
.skip(parsimmon.optWhitespace),
(...arr) => arr.flat(2)
);
},
Value: function (r) {
return parsimmon.alt(
r.NullValue,
r.BooleanValue,
r.NumberValue,
r.StringValueSql,
r.StringValueJs,
r.FuncValue,
r.CaseStatement
);
},
ValueExpression: function (r) {
return binaryLeft(
parsimmon.string("||").skip(parsimmon.optWhitespace),
binaryLeft(
parsimmon
.alt(parsimmon.string("+"), parsimmon.string("-"))
.skip(parsimmon.optWhitespace),
binaryLeft(
parsimmon
.alt(
parsimmon.string("*"),
parsimmon.string("/"),
parsimmon.string("%")
)
.skip(parsimmon.optWhitespace),
parsimmon.alt(
r.Value,
r.Parameter,
r.Expression.wrap(
parsimmon.string("(").skip(parsimmon.optWhitespace),
parsimmon.string(")").skip(parsimmon.optWhitespace)
)
)
)
)
);
},
Comparison: function (r) {
return parsimmon.alt(
parsimmon.seqMap(r.ValueExpression, r.IsNullOperator, (p, o) => [o, p]),
parsimmon.seqMap(
r.ValueExpression,
r.ComparisonOperator,
r.ValueExpression,
(p, o, v) => [o, p, v]
),
parsimmon.seqMap(
r.ValueExpression,
r.LikeOperator,
r.ValueExpression.skip(
parsimmon
.regexp(/escape/i)
.result("ESCAPE")
.skip(parsimmon.whitespace)
.desc("ESCAPE")
),
r.ValueExpression,
(a, b, c, d) => [b, a, c, d]
),
parsimmon.seqMap(
r.ValueExpression,
r.LikeOperator,
r.ValueExpression,
(a, b, c) => [b, a, c]
)
);
},
ExpressionList: function (r) {
return r.Expression.sepBy(
parsimmon.string(",").skip(parsimmon.optWhitespace)
);
},
Expression: function (r) {
function unary(
operatorsParser: parsimmon.Parser<string>,
nextParser: parsimmon.Parser<Expression>
): parsimmon.Parser<Expression> {
return parsimmon.seq(operatorsParser, nextParser).or(nextParser);
}
return binaryLeft(
r.OrOperator,
binaryLeft(
r.AndOperator,
unary(r.NotOperator, r.Comparison.or(r.ValueExpression))
)
).trim(parsimmon.optWhitespace);
},
});
export function parse(str: string): Expression {
if (!str) return null;
return lang.Expression.tryParse(str);
}
export function parseList(str: string): Expression[] {
if (!str) return [];
return lang.ExpressionList.tryParse(str);
}
export function stringify(exp: Expression, level = 0): string {
if (!Array.isArray(exp)) return JSON.stringify(exp);
const opLevels = {
OR: 10,
AND: 11,
NOT: 12,
"=": 20,
"<>": 20,
">": 20,
">=": 20,
"<": 20,
"<=": 20,
LIKE: 20,
"NOT LIKE": 20,
"IS NULL": 20,
"IS NOT NULL": 20,
"||": 30,
"+": 31,
"-": 31,
"*": 32,
"/": 32,
"%": 32,
};
const op = exp[0].toUpperCase();
function wrap(e): string {
if (opLevels[op] <= level) return `(${e})`;
else return e;
}
if (op === "FUNC") {
return wrap(
`${exp[1]}(${exp
.slice(2)
.map((e) => stringify(e))
.join(", ")})`
);
} else if (op === "PARAM") {
if (typeof exp[1] === "string") {
return wrap(exp[1]);
} else if (Array.isArray(exp[1]) && exp[1][0] === "||") {
return wrap(
exp[1]
.slice(1)
.map((p) => {
if (typeof p === "string") return p;
else return `{${stringify(p)}}`;
})
.join("")
);
} else {
return wrap(`{${stringify(exp[1])}}`);
}
} else if (op === "IS NULL" || op === "IS NOT NULL") {
return wrap(`${stringify(exp[1], opLevels[op])} ${op}`);
} else if (op === "LIKE" || op === "NOT LIKE") {
if (exp[3]) {
return wrap(
`${stringify(exp[1], opLevels[op])} ${op} ${stringify(
exp[2],
opLevels[op]
)} ESCAPE ${stringify(exp[3], opLevels[op])}`
);
} else {
return wrap(
`${stringify(exp[1], opLevels[op])} ${op} ${stringify(
exp[2],
opLevels[op]
)}`
);
}
} else if (op === "CASE") {
const parts: string[] = ["CASE"];
for (let i = 1; i < exp.length - 1; i += 2) {
if (!Array.isArray(exp[i]) && exp[i]) {
if (exp[i + 1] != null) parts.push("ELSE", stringify(exp[i + 1]));
break;
}
parts.push("WHEN", stringify(exp[i]), "THEN", stringify(exp[i + 1]));
}
parts.push("END");
return parts.join(" ");
} else if (op in opLevels) {
const parts = exp.slice(1).map((e, i) => {
return stringify(e, opLevels[exp[0]] + Math.min(i - 1, 0));
});
if (op === "NOT") return wrap(`${op} ${parts[0]}`);
else return wrap(parts.join(` ${op} `));
} else {
throw new Error(`Unrecognized operator ${exp[0]}`);
}
}
export function parseLikePattern(pat: string, esc: string): string[] {
const chars = pat.split("");
for (let i = 0; i < chars.length; ++i) {
const c = chars[i];
if (c === esc) {
chars[i] = chars[i + 1] || "";
chars[i + 1] = "";
} else if (c === "_") {
chars[i] = "\\_";
} else if (c === "%") {
chars[i] = "\\%";
while (chars[i + 1] === "%") chars[++i] = "";
}
}
return chars.filter((c) => c);
}