Separate parser and helpers from Password class for better testability

passKit/Parser/Parser.swift

@@ -0,0 +1,93 @@
+//
+//  Parser.swift
+//  passKit
+//
+//  Created by Danny Moesch on 16.08.18.
+//  Copyright © 2018 Bob Sun. All rights reserved.
+//
+
+class Parser {
+
+    let firstLine: String
+    let additionsSection: String
+    let purgedAdditionalLines: [String]
+
+    // The parsing process is expensive. This field makes sure it is only done once if actually needed.
+    private(set) lazy var additionFields = getAdditionFields()
+
+    init(plainText: String) {
+        let splittedPlainText = plainText
+            .split(omittingEmptySubsequences: false) { $0 == "\n" || $0 == "\r\n" }
+            .map(String.init)
+
+        firstLine = splittedPlainText.first!
+        additionsSection = splittedPlainText[1...].joined(separator: "\n")
+        purgedAdditionalLines = splittedPlainText[1...].filter { !$0.isEmpty }
+    }
+
+    private func getAdditionFields() -> [AdditionField] {
+        var additions: [AdditionField] = []
+        var unknownIndex: UInt = 0
+        var i = purgedAdditionalLines.startIndex
+        while i < purgedAdditionalLines.count {
+            let line = purgedAdditionalLines[i]
+            i += 1
+            var (key, value) = Parser.getKeyValuePair(from: line)
+            if key == nil {
+                unknownIndex += 1
+                key = Constants.unknown(unknownIndex)
+            } else if value == Constants.MULTILINE_WITH_LINE_BREAK_INDICATOR {
+                value = gatherMultilineValue(startingAt: &i, removingLineBreaks: false)
+            } else if value == Constants.MULTILINE_WITHOUT_LINE_BREAK_INDICATOR {
+                value = gatherMultilineValue(startingAt: &i, removingLineBreaks: true)
+            }
+            additions.append(key! => value)
+        }
+        return additions
+    }
+
+    private func gatherMultilineValue(startingAt i: inout Int, removingLineBreaks: Bool) -> String {
+        var result = ""
+        guard i < purgedAdditionalLines.count else {
+            return result
+        }
+        let numberInitialBlanks = purgedAdditionalLines[i].enumerated().first {
+            $1 != Character(Constants.BLANK)
+        }?.0 ?? purgedAdditionalLines[i].count
+        guard numberInitialBlanks != 0 else {
+            return result
+        }
+        let initialBlanks = String(repeating: Constants.BLANK, count: numberInitialBlanks)
+
+        while i < purgedAdditionalLines.count && purgedAdditionalLines[i].starts(with: initialBlanks) {
+            result.append(String(purgedAdditionalLines[i].dropFirst(numberInitialBlanks)))
+            result.append(Constants.getSeparator(breakingLines: !removingLineBreaks))
+            i += 1
+        }
+        return result.trimmingCharacters(in: .whitespacesAndNewlines)
+    }
+
+    /// Split line from password file in to a key-value pair separted by `: `.
+    ///
+    /// - Parameter line: Line from a password file
+    /// - Returns: Pair of two `String`s of which the first one can be 'nil'
+    static func getKeyValuePair(from line: String) -> (key: String?, value: String) {
+        let items = line.components(separatedBy: ": ").map { String($0).trimmingCharacters(in: .whitespaces) }
+        var key: String?
+        var value = ""
+        if items.count == 1 || (items[0].isEmpty && items[1].isEmpty) {
+            // No ': ' found, or empty on both sides of ': '.
+            value = line
+            // "otpauth" special case
+            if value.hasPrefix(Constants.OTPAUTH_URL_START) {
+                key = Constants.OTPAUTH
+            }
+        } else {
+            if !items[0].isEmpty {
+                key = items[0]
+            }
+            value = items[1]
+        }
+        return (key, value)
+    }
+}