Implement Data reading and writing (swiftlang#377)

* Implement Data reading and writing

* Use swift-foundation-local for dependency name in benchmark

Author: parkera

Benchmarks/Benchmarks/DataIO/DataIO.swift

@@ -0,0 +1,87 @@
+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2022-2023 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 the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+
+import Benchmark
+import func Benchmark.blackHole
+@testable import FoundationEssentials
+
+#if canImport(Glibc)
+import Glibc
+#endif
+#if canImport(Darwin)
+import Darwin
+#endif
+
+func testPath() -> String {
+    // Generate a random file name
+    String.temporaryDirectoryPath.appendingPathComponent("testfile-\(UUID().uuidString)")
+}
+
+func generateTestData() -> Data {
+    // 16 MB file, big enough to trigger things like chunking
+    let count = 1 << 24
+    
+    let memory = malloc(count)!
+    let ptr = memory.bindMemory(to: UInt8.self, capacity: count)
+    
+    // Set a few bytes so we're sure to not be all zeros
+    let buf = UnsafeMutableBufferPointer(start: ptr, count: count)
+    for i in 0..<128 {
+        buf[i] = UInt8.random(in: 1..<42)
+    }
+    
+    return Data(bytesNoCopy: ptr, count: count, deallocator: .free)
+}
+
+func cleanup(at path: String) {
+    _ = unlink(path)
+    // Ignore any errors
+}
+
+let data = generateTestData()
+let readMe = testPath()
+
+let benchmarks = {
+    Benchmark.defaultConfiguration.maxIterations = 1_000_000_000
+    Benchmark.defaultConfiguration.maxDuration = .seconds(3)
+    Benchmark.defaultConfiguration.scalingFactor = .kilo
+//    Benchmark.defaultConfiguration.metrics = .arc + [.cpuTotal, .wallClock, .mallocCountTotal, .throughput] // use ARC to see traffic
+//  Benchmark.defaultConfiguration.metrics = [.cpuTotal, .wallClock, .mallocCountTotal, .throughput] // skip ARC as it has some overhead
+  Benchmark.defaultConfiguration.metrics = .all // Use all metrics to easily see which ones are of interest for this benchmark suite
+
+    Benchmark("read-write-emptyFile") { benchmark in
+        let path = testPath()
+        let data = Data()
+        try data.write(to: path)
+        let read = try Data(contentsOf: path, options: [])
+        cleanup(at: path)
+    }
+
+    Benchmark("write-regularFile") { benchmark in
+        let path = testPath()
+        try data.write(to: path)
+        cleanup(at: path)
+    }
+    
+    Benchmark("read-regularFile", 
+              configuration: .init(
+                setup: {
+                    try! data.write(to: readMe)
+                },
+                teardown: {
+                    cleanup(at: readMe)
+                }
+              )
+    ) { benchmark in
+        blackHole(try Data(contentsOf: readMe))
+    }
+}

Benchmarks/Package.swift

@@ -44,5 +44,17 @@ let package = Package(
                 .plugin(name: "BenchmarkPlugin", package: "package-benchmark")
             ]
         ),
+        .executableTarget(
+            name: "DataIOBenchmarks",
+            dependencies: [
+                .product(name: "FoundationEssentials", package: "swift-foundation-local"),
+                .product(name: "Benchmark", package: "package-benchmark"),
+            ],
+            path: "Benchmarks/DataIO",
+            plugins: [
+                .plugin(name: "BenchmarkPlugin", package: "package-benchmark")
+            ]
+        ),
+
     ]
 )

Sources/FoundationEssentials/CocoaError.swift

@@ -42,7 +42,7 @@ public struct CocoaError : CustomNSError, _StoredError, Hashable {
     public let code: Code
     public let userInfo: [String: AnyHashable]
 
-    public init(code: Code, userInfo: [String: AnyHashable]) {
+    public init(_ code: Code, userInfo: [String: AnyHashable] = [:]) {
         self.code = code
         self.userInfo = userInfo
     }
@@ -187,7 +187,7 @@ extension CocoaError {
         if let url = url {
             info["NSURLErrorKey"] = url
         }
-        return CocoaError(code: code, userInfo: info)
+        return CocoaError(code, userInfo: info)
     }
 #endif
 }
@@ -275,3 +275,11 @@ public extension Error {
 #endif
 
 
+#if FOUNDATION_FRAMEWORK
+#else
+// These are loosely typed, as a typedef for String called NSErrorUserInfoKey
+internal let NSUnderlyingErrorKey = "NSUnderlyingErrorKey"
+internal let NSUserStringVariantErrorKey = "NSUserStringVariantErrorKey"
+internal let NSFilePathErrorKey = "NSFilePathErrorKey"
+internal let NSURLErrorKey = "NSURLErrorKey"
+#endif

Sources/FoundationEssentials/Data/Data+Error.swift

@@ -0,0 +1,94 @@
+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2014 - 2017 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 the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+
+#if FOUNDATION_FRAMEWORK
+// For Logger
+@_implementationOnly import os
+@_implementationOnly import _ForSwiftFoundation
+@_implementationOnly import _CShims
+#else
+package import _CShims
+#endif
+
+#if canImport(Darwin)
+import Darwin
+#elseif canImport(Glibc)
+import Glibc
+#endif
+
+internal func fileReadingOrWritingError(posixErrno: Int32, path: PathOrURL?, reading: Bool, variant: String? = nil, extraUserInfo: [String: AnyHashable] = [:]) -> Error {
+    let code: CocoaError.Code
+    if reading {
+        switch posixErrno {
+        case EFBIG:
+            code = .fileReadTooLarge
+        case ENOENT:
+            code = .fileReadNoSuchFile
+        case EPERM, EACCES:
+            code = .fileReadNoPermission
+        case ENAMETOOLONG:
+            code = .fileReadInvalidFileName
+        default:
+            code = .fileReadUnknown
+        }
+    } else {
+        switch posixErrno {
+        case ENOENT:
+            code = .fileNoSuchFile
+        case EPERM, EACCES:
+            code = .fileWriteNoPermission
+        case ENAMETOOLONG:
+            code = .fileWriteInvalidFileName
+        case EDQUOT, ENOSPC:
+            code = .fileWriteOutOfSpace
+        case EROFS:
+            code = .fileWriteVolumeReadOnly
+        case EEXIST:
+            code = .fileWriteFileExists
+        default:
+            code = .fileWriteUnknown
+        }
+    }
+    
+    var userInfo : [String : AnyHashable] = [:]
+    if let posixError = POSIXErrorCode(rawValue: posixErrno) {
+        userInfo[NSUnderlyingErrorKey] = POSIXError(posixError)
+    }
+    
+    if let variant {
+        userInfo[NSUserStringVariantErrorKey] = [variant]
+    }
+    
+    if let path {
+        switch path {
+        case .path(let path):
+            userInfo[NSFilePathErrorKey] = path
+        case .url(let url):
+            userInfo[NSURLErrorKey] = url
+        }
+    }
+    
+    if !extraUserInfo.isEmpty {
+        for (k, v) in extraUserInfo {
+            userInfo[k] = v
+        }
+    }
+    
+    return CocoaError(code, userInfo: userInfo)
+}
+
+internal func logFileIOErrno(_ err: Int32, at place: String) {
+#if FOUNDATION_FRAMEWORK && !os(bridgeOS)
+    let errnoDesc = String(cString: strerror(err))
+    Logger(_NSOSLog()).error("Encountered \(place) failure \(err) \(errnoDesc)")
+#endif
+}