Use throwing readToEnd for debugging and error handling

Package.swift

@@ -19,7 +19,7 @@ let swiftSettings: [SwiftSetting] = [
 let package = Package(
     name: "SwiftDocC",
     platforms: [
-        .macOS(.v10_15),
+        .macOS(.v11),
         .iOS(.v13)
     ],
     products: [
@@ -91,6 +91,7 @@ let package = Package(
         .target(
             name: "SwiftDocCTestUtilities",
             dependencies: [
+                "SwiftDocC",
                 .product(name: "SymbolKit", package: "swift-docc-symbolkit"),
             ],
             swiftSettings: swiftSettings

Sources/SwiftDocC/Indexing/Navigator/NavigatorIndex+Ext.swift

@@ -48,8 +48,9 @@ public class FileSystemRenderNodeProvider: RenderNodeProvider {
                 if file.url.pathExtension.lowercased() == "json" {
                     do {
                         let fileHandle = try FileHandle(forReadingFrom: file.url)
-                        let data = fileHandle.readDataToEndOfFile()
-                        renderNode = try RenderNode.decode(fromJSON: data)
+                        if let data = try fileHandle.readToEnd() {
+                            renderNode = try RenderNode.decode(fromJSON: data)
+                        }
                     } catch {
                         let diagnostic = Diagnostic(source: file.url,
                                                          severity: .warning,

Sources/SwiftDocC/Indexing/Navigator/NavigatorIndex.swift

@@ -61,9 +61,8 @@ public class NavigatorIndex {
 
     /// A specific error to describe issues when processing a `NavigatorIndex`.
     public enum Error: Swift.Error, DescribedError {
-
         /// Missing bundle identifier.
-        case missingBundleIndentifier
+        case missingBundleIdentifier
 
         /// A RenderNode has no title and won't be indexed.
         case missingTitle(description: String)
@@ -72,8 +71,8 @@ public class NavigatorIndex {
         case navigatorIndexIsNil
 
         public var errorDescription: String {
-            switch self  {
-            case .missingBundleIndentifier:
+            switch self {
+            case .missingBundleIdentifier:
                 return "A navigator index requires a bundle identifier, which is missing."
             case .missingTitle:
                 return "The page has no valid title available."
@@ -169,16 +168,17 @@ public class NavigatorIndex {
 
         let information = try environment.openDatabase(named: "information", flags: [])
 
-        let availabilityIndexFileHandle = try FileHandle(
-            forReadingFrom: url.appendingPathComponent("availability.index", isDirectory: false)
-        )
-        let data = availabilityIndexFileHandle.readDataToEndOfFile()
+        let availabilityIndexFileURL = url.appendingPathComponent("availability.index", isDirectory: false)
+        let availabilityIndexFileHandle = try FileHandle(forReadingFrom: availabilityIndexFileURL)
+        guard let data = try availabilityIndexFileHandle.readToEnd() else {
+            throw FileSystemError.noDataReadFromFile(path: availabilityIndexFileURL.path)
+        }
         let plistDecoder = PropertyListDecoder()
         let availabilityIndex = try plistDecoder.decode(AvailabilityIndex.self, from: data)
         let bundleIdentifier = bundleIdentifier ?? information.get(type: String.self, forKey: NavigatorIndex.bundleKey) ?? NavigatorIndex.UnknownBundleIdentifier
 
         guard bundleIdentifier != NavigatorIndex.UnknownBundleIdentifier else {
-            throw Error.missingBundleIndentifier
+            throw Error.missingBundleIdentifier
         }
 
         // Use `.fnv1` by default if no path hasher is set for compatibility reasons.
@@ -285,7 +285,7 @@ public class NavigatorIndex {
         self.availabilityIndex = AvailabilityIndex()
 
         guard self.bundleIdentifier != NavigatorIndex.UnknownBundleIdentifier else {
-            throw Error.missingBundleIndentifier
+            throw Error.missingBundleIdentifier
         }
     }
 

Sources/SwiftDocC/Indexing/Navigator/NavigatorTree.swift

@@ -140,7 +140,9 @@ public class NavigatorTree {
         broadcast: BroadcastCallback?
     ) throws {
         let fileHandle = try FileHandle(forReadingFrom: url)
-        let data = fileHandle.readDataToEndOfFile()
+        guard let data = try fileHandle.readToEnd() else {
+            throw Error.cannotOpenFile(path: url.path)
+        }
         let readingCursor = ReadingCursor(data: data)
         self.readingCursor = readingCursor
 
@@ -322,10 +324,12 @@ public class NavigatorTree {
         presentationIdentifier: String? = nil,
         onNodeRead: ((NavigatorTree.Node) -> Void)? = nil
     ) throws -> NavigatorTree {
-        guard let fileHandle = FileHandle(forReadingAtPath: path) else {
+        guard 
+            let fileHandle = FileHandle(forReadingAtPath: path),
+            let data = try fileHandle.readToEnd()
+        else {
             throw Error.cannotOpenFile(path: path)
         }
-        let data = fileHandle.readDataToEndOfFile()
 
         var map = [UInt32: Node]()
         var index: UInt32 = 0

Sources/SwiftDocC/Infrastructure/Bundle Assets/SVGIDExtractor.swift

@@ -40,11 +40,14 @@ enum SVGIDExtractor {
     /// Returns nil if any errors are encountered or if an `id` attribute is
     /// not found in the given SVG.
     static func extractID(from svg: URL) -> String? {
-        guard let fileHandle = try? FileHandle(forReadingFrom: svg) else {
+        guard
+            let fileHandle = try? FileHandle(forReadingFrom: svg),
+            let data = try? fileHandle.readToEnd()
+        else {
             return nil
         }
 
-        return _extractID(from: fileHandle.readDataToEndOfFile())
+        return _extractID(from: data)
     }
 }
 

Sources/SwiftDocC/Infrastructure/Workspace/LocalFileSystemDataProvider.swift

@@ -49,6 +49,10 @@ public struct LocalFileSystemDataProvider: DocumentationWorkspaceDataProvider, F
     public func contentsOfURL(_ url: URL) throws -> Data {
         precondition(url.isFileURL, "Unexpected non-file url '\(url)'.")
         let fileHandle = try FileHandle(forReadingFrom: url)
-        return fileHandle.readDataToEndOfFile()
+        guard let data = try fileHandle.readToEnd() else {
+            throw FileSystemError.noDataReadFromFile(path: url.path)
+        }
+
+        return data
     }
 }

Sources/SwiftDocC/Infrastructure/Workspace/PrebuiltLocalFileSystemDataProvider.swift

@@ -29,7 +29,11 @@ public struct PrebuiltLocalFileSystemDataProvider: DocumentationWorkspaceDataPro
     public func contentsOfURL(_ url: URL) throws -> Data {
         precondition(url.isFileURL, "Unexpected non-file url '\(url)'.")
         let fileHandle = try FileHandle(forReadingFrom: url)
-        return fileHandle.readDataToEndOfFile()
+        guard let data = try fileHandle.readToEnd() else {
+            throw FileSystemError.noDataReadFromFile(path: url.path)
+        }
+
+        return data
     }
 }
 

Sources/SwiftDocC/Servers/FileServer.swift

@@ -174,7 +174,7 @@ public class FileSystemServerProvider: FileServerProvider {
     public func data(for path: String) -> Data? {
         let finalURL = directoryURL.appendingPathComponent(path)
         let fileHandle = try? FileHandle(forReadingFrom: finalURL)
-        return fileHandle?.readDataToEndOfFile()
+        return try? fileHandle?.readToEnd()
     }
 
 }
@@ -229,9 +229,12 @@ public class MemoryFileServerProvider: FileServerProvider {
 
         for file in enumerator {
             guard let file = file as? String else { fatalError("Enumerator returned an unexpected type.") }
-            guard let fileHandle = try? FileHandle(forReadingFrom: URL(fileURLWithPath: path).appendingPathComponent(file))
+            let fileURL = URL(fileURLWithPath: path).appendingPathComponent(file)
+            guard
+                let fileHandle = try? FileHandle(forReadingFrom: fileURL),
+                let data = try? fileHandle.readToEnd()
             else { continue }
-            let data = fileHandle.readDataToEndOfFile()
+
             if recursive == false && file.contains("/") { continue } // skip if subfolder and recursive is disabled
             addFile(path: "/\(trimmedSubPath)/\(file)", data: data)
         }

Sources/SwiftDocC/Utility/Errors/FileSystemError.swift

@@ -0,0 +1,21 @@
+/*
+ This source file is part of the Swift.org open source project
+
+ Copyright (c) 2021 Apple Inc. and the Swift project authors
+ Licensed under Apache License v2.0 with Runtime Library Exception
+
+ See https://swift.org/LICENSE.txt for license information
+ See https://swift.org/CONTRIBUTORS.txt for Swift project authors
+*/
+
+public enum FileSystemError: Error, DescribedError {
+    /// No data could be read from file at `path`.
+    case noDataReadFromFile(path: String)
+
+    public var errorDescription: String {
+        switch self {
+        case .noDataReadFromFile(let path):
+            return "No data could be read from file at `\(path)`"
+        }
+    }
+}

Sources/SwiftDocCTestUtilities/FilesAndFolders.swift

@@ -9,6 +9,7 @@
 */
 
 import Foundation
+import SwiftDocC
 import XCTest
 
 /*
@@ -201,7 +202,10 @@ public struct CopyOfFile: File, DataRepresentable {
         var isDirectory: ObjCBool = false
         guard FileManager.default.fileExists(atPath: original.path, isDirectory: &isDirectory), !isDirectory.boolValue else { throw Error.notAFile(original) }
         let fileHandle = try FileHandle(forReadingFrom: original)
-        return fileHandle.readDataToEndOfFile()
+        guard let data = try fileHandle.readToEnd() else {
+            throw FileSystemError.noDataReadFromFile(path: original.path)
+        }
+        return data
     }
 
     public func write(to url: URL) throws {

Sources/SwiftDocCUtilities/PreviewServer/RequestHandler/DefaultRequestHandler.swift

@@ -12,6 +12,7 @@
 import Foundation
 import NIO
 import NIOHTTP1
+import SwiftDocC
 
 /// A request handler that serves the default app page to clients.
 ///
@@ -28,9 +29,12 @@ struct DefaultRequestHandler: RequestHandlerFactory {
         where ChannelHandler.OutboundOut == HTTPServerResponsePart {
 
         return { context, head in
-            let fileHandle = try FileHandle(forReadingFrom: self.rootURL.appendingPathComponent("index.html"))
-            let response = fileHandle.readDataToEndOfFile()
-
+            let fileURL = self.rootURL.appendingPathComponent("index.html")
+            let fileHandle = try FileHandle(forReadingFrom: fileURL)
+            guard let response = try fileHandle.readToEnd() else {
+                throw FileSystemError.noDataReadFromFile(path: fileURL.path)
+            }
+
             var content = context.channel.allocator.buffer(capacity: response.count)
             content.writeBytes(response)
 

Sources/SwiftDocCUtilities/PreviewServer/RequestHandler/FileRequestHandler.swift

@@ -158,13 +158,16 @@ struct FileRequestHandler: RequestHandlerFactory {
                 // Read the file contents
                 do {
                     let fileHandle = try FileHandle(forReadingFrom: fileURL)
-                    data = fileHandle.readDataToEndOfFile()
+                    guard let readData = try fileHandle.readToEnd() else {
+                        throw FileSystemError.noDataReadFromFile(path: fileURL.path)
+                    }
+                    data = readData
                     totalLength = data.count
                 } catch {
                     throw RequestError(status: .notFound)
                 }
 
-                // Add Range header if neccessary
+                // Add Range header if necessary
                 var headers = HTTPHeaders()
                 let range = head.headers["Range"].first.flatMap(RangeHeader.init)
                 if let range = range {

Sources/generate-symbol-graph/main.swift

@@ -164,6 +164,10 @@ let supportedDirectives: [Directive] = [
         )
     }
 
+enum SymbolGraphError: Error {
+    case noDataReadFromFile(path: String)
+}
+
 func generateSwiftDocCFrameworkSymbolGraph() throws -> SymbolGraph {
     let packagePath = URL(fileURLWithPath: #file)
         .deletingLastPathComponent() // generate-symbol-graph
@@ -207,7 +211,9 @@ func generateSwiftDocCFrameworkSymbolGraph() throws -> SymbolGraph {
     )
 
     let symbolGraphFileHandle = try FileHandle(forReadingFrom: symbolGraphURL)
-    let symbolGraphData = symbolGraphFileHandle.readDataToEndOfFile()
+    guard let symbolGraphData = try symbolGraphFileHandle.readToEnd() else {
+        throw SymbolGraphError.noDataReadFromFile(path: symbolGraphURL.path)
+    }
     return try JSONDecoder().decode(SymbolGraph.self, from: symbolGraphData)
 }