keep a cache around and use it if available when linting

speeds up lint operation by avoiding having to re-parse all files

Sources/stringray/Commands/CopyCommand.swift

@@ -54,6 +54,6 @@ struct CopyCommand: Command {
 
 		let filteredTable = fromTable.withKeys(matching: matching)
 		toTable.addEntries(from: filteredTable)
-		try write(to: to.resourceDirectory, table: toTable)
+		try loader.write(to: to.resourceDirectory, table: toTable)
 	}
 }

Sources/stringray/Commands/LintCommand.swift

@@ -159,10 +159,20 @@ struct LintCommand: Command {
 		var loader = StringsTableLoader()
 		loader.options = [.lineNumbers]
 		let linter = Linter(reporter: reporter, config: config)
+		var allError = Linter.Error([])
+
 		try inputs.forEach {
 			print("Linting: \($0.tableName)")
 			let table = try loader.load(url: $0.resourceURL, name: $0.tableName, base: $0.locale)
-			try linter.report(on: table, url: $0.resourceURL)
+			do {
+				try linter.report(on: table, url: $0.resourceURL)
+				try loader.writeCache(table: table, baseURL: $0.resourceURL)
+			} catch let error as Linter.Error {
+				allError.violations.append(contentsOf: error.violations)
+			}
+		}
+		if !allError.violations.isEmpty {
+			throw allError
 		}
 	}
 }

Sources/stringray/Commands/MoveCommand.swift

@@ -55,7 +55,7 @@ struct MoveCommand: Command {
 		let filteredTable = fromTable.withKeys(matching: matching)
 		toTable.addEntries(from: filteredTable)
 		fromTable.removeEntries(from: filteredTable)
-		try write(to: to.resourceDirectory, table: toTable)
-		try write(to: from.resourceDirectory, table: fromTable)
+		try loader.write(to: to.resourceDirectory, table: toTable)
+		try loader.write(to: from.resourceDirectory, table: fromTable)
 	}
 }

Sources/stringray/Commands/RenameCommand.swift

@@ -49,8 +49,9 @@ struct RenameCommand: Command {
 	}
 
 	private func rename(url: Foundation.URL, matching: [Match], replacements replacementStrings: [String]) throws {
-		var table = try StringsTableLoader().load(url: url)
+		let loader = StringsTableLoader()
+		var table = try loader.load(url: url)
 		table.replace(matches: matching, replacements: replacementStrings)
-		try write(to: url.resourceDirectory, table: table)
+		try loader.write(to: url.resourceDirectory, table: table)
 	}
 }

Sources/stringray/Commands/SortCommand.swift

@@ -35,8 +35,9 @@ struct SortCommand: Command {
 	}
 
 	private func sort(url: Foundation.URL) throws {
-		var table = try StringsTableLoader().load(url: url)
+		let loader = StringsTableLoader()
+		var table = try loader.load(url: url)
 		table.sort()
-		try write(to: url.resourceDirectory, table: table)
+		try loader.write(to: url.resourceDirectory, table: table)
 	}
 }

Sources/stringray/Lint Rules/Linter.swift

@@ -50,8 +50,17 @@ struct Linter {
 		MissingPlaceholderLintRule()
 	]
 
-	private enum LintError: Swift.Error {
-		case violations
+	struct Error: LocalizedError {
+		var violations: [LintRuleViolation]
+		init(_ violations: [LintRuleViolation]) {
+			self.violations = violations
+		}
+
+		var errorDescription: String? {
+			let errorCount = violations.filter { $0.severity == .error }.count
+			let warningCount = violations.filter { $0.severity == .warning }.count
+			return "Encountered \(errorCount) errors and \(warningCount) warnings."
+		}
 	}
 
 	let rules: [LintRule]
@@ -89,7 +98,7 @@ struct Linter {
 		var outputStream = LinterOutputStream(fileHandle: FileHandle.standardOutput)
 		reporter.generateReport(for: violations, to: &outputStream)
 		if !violations.isEmpty {
-			throw LintError.violations
+			throw Linter.Error(violations)
 		}
 	}
 }

Sources/stringray/Strings Table/Cache/CachedStringsTable.swift

@@ -0,0 +1,57 @@
+//
+//  CachedStringsTable.swift
+//  stringray
+//
+//  Created by Geoffrey Foster on 2018-12-12.
+//
+
+import Foundation
+
+struct CachedStringsTable: Codable {
+	let stringsTable: StringsTable
+	let cacheKeys: [String: Date]
+
+	enum LocalizationType {
+		case strings
+		case stringsdict
+	}
+
+    init(stringsTable: StringsTable, cacheKeys: [String: Date]) {
+        self.stringsTable = stringsTable
+        self.cacheKeys = cacheKeys
+    }
+
+	func strings(for locale: Locale) -> OrderedSet<StringsTable.Entry>? {
+		return stringsTable.entries[locale]
+	}
+
+	func stringsDict(for locale: Locale) -> [String: StringsTable.DictEntry]? {
+		return stringsTable.dictEntries[locale]
+	}
+
+	func isCacheValid(for locale: Locale, type: LocalizationType, base: URL) -> Bool {
+		do {
+			let fileURL: URL
+			switch type {
+			case .strings:
+				fileURL = try base.stringsURL(tableName: stringsTable.name, locale: locale)
+			case .stringsdict:
+				fileURL = try base.stringsDictURL(tableName: stringsTable.name, locale: locale)
+			}
+			let attributes = try FileManager.default.attributesOfItem(atPath: fileURL.path)
+			guard let modificationDate = attributes[.modificationDate] as? Date else { return false }
+			return modificationDate == cacheKeys[CachedStringsTable.cacheKey(for: locale, type: type)]
+		} catch {
+			return false
+		}
+	}
+
+	static func cacheKey(for locale: Locale, type: LocalizationType) -> String {
+		switch type {
+		case .strings:
+			return "\(locale.identifier).strings"
+		case .stringsdict:
+			return "\(locale.identifier).stringsdict"
+		}
+	}
+}

Sources/stringray/Strings Table/StringsTable.swift

@@ -8,7 +8,7 @@
 
 import Foundation
 
-struct StringsTable: Codable {	
+struct StringsTable: Codable {
 	typealias EntriesType = [Locale: OrderedSet<Entry>]
 	typealias DictEntriesType = [Locale: [String: DictEntry]]
 

Sources/stringray/Strings Table/StringsTableLoader.swift

@@ -24,6 +24,7 @@ struct StringsTableLoader {
 		public init(rawValue: UInt) { self.rawValue = rawValue }
 
 		public static let lineNumbers = Options(rawValue: 1 << 0)
+		public static let ignoreCached = Options(rawValue: 1 << 1)
 	}
 
 	var options: Options = []
@@ -40,23 +41,95 @@ struct StringsTableLoader {
 		var entries: StringsTable.EntriesType = [:]
 		var dictEntries: StringsTable.DictEntriesType = [:]
 
+		var cached: CachedStringsTable?
+		if !options.contains(.ignoreCached), let url = cacheURL(for: name), let data = try? Data(contentsOf: url) {
+			let decoder = PropertyListDecoder()
+			cached = try? decoder.decode(CachedStringsTable.self, from: data)
+		}
+
 		try url.lprojURLs.forEach {
 			guard let locale = $0.locale else { return }
 
 			let stringsTableURL = $0.appendingPathComponent(name).appendingPathExtension("strings")
-			if let reachable = try? stringsTableURL.checkResourceIsReachable(), reachable == true {
+			if let cached = cached, cached.isCacheValid(for: locale, type: .strings, base: url), let cachedStrings = cached.strings(for: locale) {
+				entries[locale] = cachedStrings
+			} else if let reachable = try? stringsTableURL.checkResourceIsReachable(), reachable == true {
 				entries[locale] = try load(from: stringsTableURL, options: options)
 			}
 
 			let stringsDictTableURL = $0.appendingPathComponent(name).appendingPathExtension("stringsdict")
-			if let reachable = try? stringsDictTableURL.checkResourceIsReachable(), reachable == true {
+			if let cached = cached, cached.isCacheValid(for: locale, type: .stringsdict, base: url), let cachedStringsDict = cached.stringsDict(for: locale) {
+				dictEntries[locale] = cachedStringsDict
+			} else if let reachable = try? stringsDictTableURL.checkResourceIsReachable(), reachable == true {
 				dictEntries[locale] = try load(from: stringsDictTableURL)
 			}
 		}
 
 		return StringsTable(name: name, base: base, entries: entries, dictEntries: dictEntries)
 	}
 
+	func write(to url: Foundation.URL, table: StringsTable) throws {
+		for (languageId, languageEntries) in table.entries where !languageEntries.isEmpty {
+			let fileURL = try url.stringsURL(tableName: table.name, locale: languageId)
+			guard let outputStream = OutputStream(url: fileURL, append: false) else { continue }
+			outputStream.open()
+			var firstEntry = true
+			for entry in languageEntries {
+				if !firstEntry {
+					outputStream.write(string: "\n")
+				}
+				firstEntry = false
+				outputStream.write(string: "\(entry)\n")
+			}
+			outputStream.close()
+		}
+
+		for (languageId, languageEntries) in table.dictEntries where !languageEntries.isEmpty {
+			let fileURL = try url.stringsDictURL(tableName: table.name, locale: languageId)
+			let encoder = PropertyListEncoder()
+			encoder.outputFormat = .xml
+			let data = try encoder.encode(languageEntries)
+			try data.write(to: fileURL, options: [.atomic])
+		}
+	}
+
+	func writeCache(table: StringsTable, baseURL: URL) throws {
+		var cacheKeys: [String: Date] = [:]
+
+		for (languageId, languageEntries) in table.entries where !languageEntries.isEmpty {
+			let fileURL = try baseURL.stringsURL(tableName: table.name, locale: languageId)
+			let attributes = try FileManager.default.attributesOfItem(atPath: fileURL.path)
+			guard let modificationDate = attributes[.modificationDate] as? Date else { continue }
+			cacheKeys[CachedStringsTable.cacheKey(for: languageId, type: .strings)] = modificationDate
+		}
+
+		for (languageId, languageEntries) in table.dictEntries where !languageEntries.isEmpty {
+			let fileURL = try baseURL.stringsDictURL(tableName: table.name, locale: languageId)
+			let attributes = try FileManager.default.attributesOfItem(atPath: fileURL.path)
+			guard let modificationDate = attributes[.modificationDate] as? Date else { continue }
+			cacheKeys[CachedStringsTable.cacheKey(for: languageId, type: .stringsdict)] = modificationDate
+		}
+
+		let cachedTable = CachedStringsTable(stringsTable: table, cacheKeys: cacheKeys)
+		let encoder = PropertyListEncoder()
+		encoder.outputFormat = .binary
+		let cachedData = try encoder.encode(cachedTable)
+		guard let url = cacheURL(for: table.name) else { return }
+		try cachedData.write(to: url, options: [.atomic])
+	}
+
+	private func cacheURL(for tableName: String) -> Foundation.URL? {
+		let bundleIdentifier = Bundle.main.bundleIdentifier ?? "net.g-Off.stringray"
+		let filePath = "\(bundleIdentifier)/\(tableName).localization"
+		guard let cacheURL = try? FileManager.default.url(for: .applicationSupportDirectory, in: .userDomainMask, appropriateFor: URL(fileURLWithPath: filePath), create: true)
+			else {
+				return nil
+		}
+		let fileURL = URL(fileURLWithPath: filePath, relativeTo: cacheURL)
+		try! FileManager.default.createDirectory(at: fileURL.deletingLastPathComponent(), withIntermediateDirectories: true, attributes: nil)
+		return URL(fileURLWithPath: filePath, relativeTo: cacheURL)
+	}
+
 	private func load(from url: URL, options: Options) throws -> OrderedSet<StringsTable.Entry> {
 		func lineNumber(scanLocation: Int, newlineLocations: [Int]) -> Int {
 			var lastIndex = 0
@@ -123,3 +196,10 @@ struct StringsTableLoader {
 		return try decoder.decode([String: StringsTable.DictEntry].self, from: data)
 	}
 }
+
+private extension OutputStream {
+	func write(string: String) {
+		let encodedDataArray = [UInt8](string.utf8)
+		write(encodedDataArray, maxLength: encodedDataArray.count)
+	}
+}