Merge pull request #6 from g-Off/filesystem

adding the concept of a filesystem to the template

Sources/Liquid/Context.swift

@@ -42,17 +42,21 @@ public final class Context {
 	}
 
 	private var scopes: [Scope]
-	private var filters: [String: FilterFunc]
 
 	// Registers are for internal data structure storage, like forloop's and cycles to store data
 	private var registers: [String: Any] = [:]
 
+	public let filters: [String: FilterFunc]
+	public let tags: [String: TagBuilder]
 	public let environment: Environment
 	public let encoder: Encoder
+	public let fileSystem: FileSystem
 
-	init(values: [String: Value] = [:], environment: Environment = Environment(), filters: [String: FilterFunc] = [:], encoder: Encoder) {
+	init(fileSystem: FileSystem, values: [String: Value] = [:], environment: Environment = Environment(), tags: [String: TagBuilder], filters: [String: FilterFunc] = [:], encoder: Encoder) {
+		self.fileSystem = fileSystem
 		self.scopes = [Scope(values: values)]
 		self.environment = environment
+		self.tags = tags
 		self.filters = filters
 		self.encoder = encoder
 	}

Sources/Liquid/SyntaxError.swift → Sources/Liquid/Error.swift

@@ -1,5 +1,5 @@
 //
-//  SyntaxError.swift
+//  Error.swift
 //  
 //
 //  Created by Geoffrey Foster on 2019-09-02.
@@ -18,9 +18,8 @@ public enum SyntaxError: Error {
 public enum RuntimeError: Error {
 	case wrongType(String)
 	case unknownFilter(String)
-
 	case invalidArgCount(expected: Int, received: Int, tag: String)
-
+	case reason(String) // TODO: this is just a raw string explaining the failure
 	case unimplemented
 }
 

Sources/Liquid/Template.swift

@@ -14,20 +14,43 @@ public final class Template {
 	private var filters: [String: FilterFunc] = [:]
 	private var tags: [String: TagBuilder] = [:]
 
-	private let locale: Locale
-
 	var encoder: Encoder = Encoder()
 
 	/// Environments are persisted across each render of a template so we store them as part of the template itself.
 	/// The template then injects them during a render call and copies the values back upon completion.
 	private let environment: Environment
 
-	public init(source: String, locale: Locale = .current, environment: Environment = Environment()) {
+	private let fileSystem: FileSystem
+
+	public convenience init(sourceURL: URL, encoder: Encoder = Encoder(), environment: Environment = Environment()) throws {
+		let source = try String(contentsOf: sourceURL)
+		let fileSystem = LocalFileSystem(baseURL: sourceURL.deletingLastPathComponent())
+		self.init(source: source, fileSystem: fileSystem, encoder: encoder, environment: environment)
+	}
+
+	public convenience init(source: String, encoder: Encoder = Encoder(), environment: Environment = Environment(), fileSystem: FileSystem? = nil) {
+		struct ThrowingFileSystem: FileSystem {			
+			func read(path: String) throws -> String {
+				throw RuntimeError.reason("Invalid filesystem")
+			}
+		}
+		self.init(source: source, fileSystem: fileSystem ?? ThrowingFileSystem(), encoder: encoder, environment: environment)
+	}
+
+	init(source: String, context: Context) {
+		self.source = source
+		self.encoder = context.encoder
+		self.environment = context.environment
+		self.fileSystem = context.fileSystem
+		self.filters = context.filters
+		self.tags = context.tags
+	}
+
+	private init(source: String, fileSystem: FileSystem, encoder: Encoder, environment: Environment) {
 		self.source = source
-		self.locale = locale
+		self.fileSystem = fileSystem
 		self.environment = environment
-
-		encoder.locale = locale
+		self.encoder = encoder
 
 		tags["assign"] = Assign.init
 		tags["break"] = Break.init
@@ -59,11 +82,15 @@ public final class Template {
 		tags[name] = tag
 	}
 
-	public func render(values: [String: Value] = [:]) throws -> String {
-		let context = Context(values: values, environment: environment, filters: filters, encoder: encoder)
+	public func render(context: Context) throws -> String {
 		return try root.render(context: context).joined()
 	}
 
+	public func render(values: [String: Value] = [:]) throws -> String {
+		let context = Context(fileSystem: fileSystem, values: values, environment: environment, tags: tags, filters: filters, encoder: encoder)
+		return try render(context: context)
+	}
+
 	public func render(values: [String: ValueConvertible]) throws -> String {
 		return try self.render(values: values.mapValues { try encoder.encode($0) })
 	}

Sources/Liquid/Utilities/FileSystem.swift

@@ -0,0 +1,46 @@
+//
+//  FileSystem.swift
+//  
+//
+//  Created by Geoffrey Foster on 2019-09-28.
+//
+
+import Foundation
+
+public protocol FileSystem {
+	func read(path: String) throws -> String
+}
+
+struct LocalFileSystem: FileSystem {
+	let baseURL: URL
+
+	init(baseURL: URL) {
+		self.baseURL = baseURL
+	}
+
+	func read(path: String) throws -> String {
+		let fileURL = try templateURL(for: path)
+		return try String(contentsOf: fileURL)
+	}
+
+	private func templateURL(for path: String) throws -> URL {
+		var components = path.components(separatedBy: "/")
+		guard !components.isEmpty else {
+			throw FileSystemError(reason: "")
+		}
+		let filename = "_\(components.popLast()!).liquid"
+		components.append(filename)
+		let transformedPath = components.joined(separator: "/")
+		return baseURL.appendingPathComponent(transformedPath)
+	}
+}
+
+struct BlankFileSystem: FileSystem {
+	func read(path: String) throws -> String {
+		throw FileSystemError(reason: "This liquid context does not allow includes.")
+	}
+}
+
+struct FileSystemError: Error {
+	let reason: String
+}

Sources/Liquid/Value/Encoder.swift

@@ -132,6 +132,10 @@ public struct Encoder {
 	public var decimalEncodingStrategy: DecimalEncodingStrategy = .scaled(8)
 	public internal(set) var locale: Locale = .current
 
+	public init() {
+
+	}
+
 	public func encode(_ input: Any?) throws -> Value {
 		guard let input = input else {
 			return Value()

Tests/LiquidTests/XCTestCase+Extensions.swift

@@ -8,8 +8,8 @@
 import XCTest
 @testable import Liquid
 
-func XCTAssertTemplate(_ templateString: String, _ expression2: String, _ values: [String: Any?] = [:], _ message: @autoclosure () -> String = "", file: StaticString = #file, line: UInt = #line) {
-	let template = Template(source: templateString)
+func XCTAssertTemplate(_ templateString: String, _ expression2: String, _ values: [String: Any?] = [:], fileSystem: FileSystem = BlankFileSystem(), _ message: @autoclosure () -> String = "", file: StaticString = #file, line: UInt = #line) {
+	let template = Template(source: templateString, fileSystem: fileSystem)
 	XCTAssertNoThrow(try template.parse())
 	do {
 		let result = try template.render(values: values)