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| 1 | +// |
| 2 | +// JSONPath.swift |
| 3 | +// FlyingFox |
| 4 | +// |
| 5 | +// Created by Simon Whitty on 29/05/2023. |
| 6 | +// Copyright © 2023 Simon Whitty. All rights reserved. |
| 7 | +// |
| 8 | +// Distributed under the permissive MIT license |
| 9 | +// Get the latest version from here: |
| 10 | +// |
| 11 | +// https://github.com/swhitty/FlyingFox |
| 12 | +// |
| 13 | +// Permission is hereby granted, free of charge, to any person obtaining a copy |
| 14 | +// of this software and associated documentation files (the "Software"), to deal |
| 15 | +// in the Software without restriction, including without limitation the rights |
| 16 | +// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell |
| 17 | +// copies of the Software, and to permit persons to whom the Software is |
| 18 | +// furnished to do so, subject to the following conditions: |
| 19 | +// |
| 20 | +// The above copyright notice and this permission notice shall be included in all |
| 21 | +// copies or substantial portions of the Software. |
| 22 | +// |
| 23 | +// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR |
| 24 | +// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, |
| 25 | +// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE |
| 26 | +// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER |
| 27 | +// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, |
| 28 | +// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE |
| 29 | +// SOFTWARE. |
| 30 | +// |
| 31 | + |
| 32 | +import Foundation |
| 33 | + |
| 34 | +public struct JSONPath { |
| 35 | + |
| 36 | + var components: [Component] |
| 37 | + |
| 38 | + enum Component: Equatable { |
| 39 | + case field(String) |
| 40 | + case array(Int) |
| 41 | + } |
| 42 | + |
| 43 | + init(components: [Component]) { |
| 44 | + self.components = components |
| 45 | + } |
| 46 | + |
| 47 | + public init(parsing path: String) throws { |
| 48 | + self.components = try Self.parseComponents(from: path) |
| 49 | + } |
| 50 | + |
| 51 | + private struct Error: LocalizedError { |
| 52 | + var errorDescription: String? |
| 53 | + |
| 54 | + init(_ description: String) { |
| 55 | + self.errorDescription = description |
| 56 | + } |
| 57 | + } |
| 58 | +} |
| 59 | + |
| 60 | +extension JSONPath { |
| 61 | + |
| 62 | + static func parseComponents(from path: String) throws -> [Component] { |
| 63 | + var scanner = Scanner(string: path) |
| 64 | + guard scanner.scanString("$") != nil else { |
| 65 | + throw Error("Expected $") |
| 66 | + } |
| 67 | + |
| 68 | + var comps = [Component]() |
| 69 | + while let comp = try scanComponent(from: &scanner) { |
| 70 | + comps.append(comp) |
| 71 | + } |
| 72 | + return comps |
| 73 | + } |
| 74 | + |
| 75 | + static func scanComponent(from scanner: inout Scanner) throws -> Component? { |
| 76 | + if scanner.scanString(".") != nil { |
| 77 | + guard let name = scanner.scanUpToCharacters(from: CharacterSet(charactersIn: ".[")) else { |
| 78 | + throw Error("Expected field name") |
| 79 | + } |
| 80 | + return .field(name) |
| 81 | + } else if scanner.scanString("[") != nil { |
| 82 | + guard let index = scanner.scanCharacters(from: CharacterSet(charactersIn: "0123456789")) else { |
| 83 | + throw Error("Expected index") |
| 84 | + } |
| 85 | + guard scanner.scanString("]") != nil else { |
| 86 | + throw Error("Expected ]") |
| 87 | + } |
| 88 | + return .array(Int(index)!) |
| 89 | + } |
| 90 | + guard scanner.isAtEnd else { |
| 91 | + throw Error("Expected end") |
| 92 | + } |
| 93 | + return nil |
| 94 | + } |
| 95 | +} |
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