Add PackageDescription.Context API (#3794)

* Add Package.Context

This struct contains context information available to a package manifest
at runtime. Initially, it contains the packageRoot : URL property.

* Serialize a Package.Context, and pass to manifest on command line

* Rename PackageContext -> Context, add ContextModel

ContextModel is the value type that gets serialized and wrapped by
PackageDescription.Context. ContextModel copied into PackageDescription
by symbolic link PackageModel.PackageContext.

Add .environment property to PackageDescription.Context.

* Implement ManifestLoaderDelegate, capture path to parsed manifest

* Test PackageDescription.Context

* Add .testPackageContextDirectory()

This checks that the directory contents is accessible.

* Switch from usleep() to Thread.sleep()

usleep() isn't portable.

* Add initial documentation comments

* Change all methods to be static

No need for a singleton instance.

* Update unit test to use Context.packageDirectory

* Fix bootstrap build

Add Context.swift, ContextModel.swift to CMakeLists.txt

* Make unit test more robust

Return comma separated list of Temporary*.swift

Author: pcbeard

Sources/PackageDescription/CMakeLists.txt

@@ -8,6 +8,8 @@
 
 add_library(PackageDescription
   BuildSettings.swift
+  Context.swift
+  ContextModel.swift
   LanguageStandardSettings.swift
   PackageDescription.swift
   PackageDescriptionSerialization.swift

Sources/PackageDescription/Context.swift

@@ -0,0 +1,29 @@
+/*
+ This source file is part of the Swift.org open source project
+
+ Copyright (c) 2018 Apple Inc. and the Swift project authors
+ Licensed under Apache License v2.0 with Runtime Library Exception
+
+ See http://swift.org/LICENSE.txt for license information
+ See http://swift.org/CONTRIBUTORS.txt for Swift project authors
+ */
+
+/// The context a Swift package is running in. This encapsulates states that are known at build-time.
+/// For example where in the file system the current package resides.
+@available(_PackageDescription, introduced: 5.6)
+public struct Context {
+    private static let model = ContextModel.decode()
+
+    /// The directory containing Package.swift.
+    public static var packageDirectory : String {
+        model.packageDirectory
+    }
+    
+    /// Snapshot of the system environment variables.
+    public static var environment : [String : String] {
+        model.environment
+    }
+    
+    private init() {
+    }
+}

Sources/PackageDescription/ContextModel.swift

@@ -0,0 +1 @@
+../PackageModel/ContextModel.swift

Sources/PackageLoading/ManifestLoader.swift

@@ -819,6 +819,11 @@ public final class ManifestLoader: ManifestLoaderProtocol {
 #else
             cmd += ["-fileno", "\(fileno(jsonOutputFileDesc))"]
 #endif
+
+            let packageDirectory = manifestPath.parentDirectory.pathString
+            let contextModel = ContextModel(packageDirectory: packageDirectory)
+            cmd += ["-context", contextModel.encoded]
+
             // If enabled, run command in a sandbox.
             // This provides some safety against arbitrary code execution when parsing manifest files.
             // We only allow the permissions which are absolutely necessary.

Sources/PackageModel/CMakeLists.txt

@@ -10,6 +10,7 @@ add_library(PackageModel
   BuildConfiguration.swift
   BuildEnvironment.swift
   BuildSettings.swift
+  ContextModel.swift
   Diagnostics.swift
   Manifest.swift
   Manifest/PackageConditionDescription.swift

Sources/PackageModel/ContextModel.swift

@@ -0,0 +1,60 @@
+/*
+ This source file is part of the Swift.org open source project
+
+ Copyright (c) 2014 - 2021 Apple Inc. and the Swift project authors
+ Licensed under Apache License v2.0 with Runtime Library Exception
+
+ See http://swift.org/LICENSE.txt for license information
+ See http://swift.org/CONTRIBUTORS.txt for Swift project authors
+*/
+
+import class Foundation.JSONDecoder
+import class Foundation.JSONEncoder
+import class Foundation.ProcessInfo
+
+public struct ContextModel {
+    public let packageDirectory : String
+    
+    public init(packageDirectory : String) {
+        self.packageDirectory = packageDirectory
+    }
+    
+    public var environment : [String : String] {
+        ProcessInfo.processInfo.environment
+    }
+}
+
+extension ContextModel : Codable {
+    private enum CodingKeys: CodingKey {
+        case packageDirectory
+    }
+
+    public init(from decoder: Decoder) throws {
+        let container = try decoder.container(keyedBy: CodingKeys.self)
+        self.packageDirectory = try container.decode(String.self, forKey: .packageDirectory)
+    }
+    
+    public func encode(to encoder: Encoder) throws {
+        var container = encoder.container(keyedBy: CodingKeys.self)
+        try container.encode(packageDirectory, forKey: .packageDirectory)
+    }
+
+    public var encoded : String {
+        let encoder = JSONEncoder()
+        let data = try! encoder.encode(self)
+        return String(data: data, encoding: .utf8)!
+    }
+
+    public static func decode() -> ContextModel {
+        // TODO: Look at ProcessInfo.processInfo
+        var args = Array(ProcessInfo.processInfo.arguments[1...]).makeIterator()
+        while let arg = args.next() {
+            if arg == "-context", let json = args.next() {
+                let decoder = JSONDecoder()
+                let data = json.data(using: .utf8)!
+                return (try! decoder.decode(ContextModel.self, from: data))
+            }
+        }
+        fatalError("Could not decode ContextModel parameter.")
+    }
+}

Tests/BasicsTests/ConcurrencyHelpersTests.swift

@@ -26,7 +26,7 @@ final class ConcurrencyHelpersTest: XCTestCase {
             let cache = ThreadSafeKeyValueStore<Int, Int>()
             for index in 0 ..< 1000 {
                 self.queue.async(group: sync) {
-                    usleep(UInt32.random(in: 100 ... 300))
+                    Thread.sleep(forTimeInterval: Double.random(in: 100 ... 300) * 1.0e-6)
                     let value = Int.random(in: Int.min ..< Int.max)
                     lock.withLock {
                         expected[index] = value
@@ -61,7 +61,7 @@ final class ConcurrencyHelpersTest: XCTestCase {
             let cache = ThreadSafeArrayStore<Int>()
             for _ in 0 ..< 1000 {
                 self.queue.async(group: sync) {
-                    usleep(UInt32.random(in: 100 ... 300))
+                    Thread.sleep(forTimeInterval: Double.random(in: 100 ... 300) * 1.0e-6)
                     let value = Int.random(in: Int.min ..< Int.max)
                     lock.withLock {
                         expected.append(value)
@@ -93,7 +93,7 @@ final class ConcurrencyHelpersTest: XCTestCase {
             let cache = ThreadSafeBox<Int>()
             for index in 0 ..< 1000 {
                 self.queue.async(group: sync) {
-                    usleep(UInt32.random(in: 100 ... 300))
+                    Thread.sleep(forTimeInterval: Double.random(in: 100 ... 300) * 1.0e-6)
                     serial.async(group: sync) {
                         lock.withLock {
                             if winner == nil {

Tests/PackageCollectionsTests/TrieTests.swift

@@ -203,7 +203,7 @@ class TrieTests: XCTestCase {
 
             for i in 0 ..< docCount {
                 queue.async(group: sync) {
-                    usleep(UInt32.random(in: 100 ... 300))
+                    Thread.sleep(forTimeInterval: Double.random(in: 100 ... 300) * 1.0e-6)
 
                     trie.remove { $0 == i }
                     trie.insert(word: "word-\(i)", foundIn: i)

Tests/PackageLoadingTests/PDLoadingTests.swift

@@ -16,8 +16,16 @@ import TSCBasic
 import TSCUtility
 import XCTest
 
-class PackageDescriptionLoadingTests: XCTestCase {
-    let manifestLoader = ManifestLoader(toolchain: ToolchainConfiguration.default)
+class PackageDescriptionLoadingTests: XCTestCase, ManifestLoaderDelegate {
+    lazy var manifestLoader = ManifestLoader(toolchain: ToolchainConfiguration.default, delegate: self)
+    var parsedManifest : AbsolutePath?
+
+    public func willLoad(manifest: AbsolutePath) {
+    }
+    
+    public func willParse(manifest: AbsolutePath) {
+        parsedManifest = manifest
+    }
 
     var toolsVersion: ToolsVersion {
         fatalError("implement in subclass")

Tests/PackageLoadingTests/PD_5_6_LoadingTests.swift

@@ -153,4 +153,39 @@ class PackageDescription5_6LoadingTests: PackageDescriptionLoadingTests {
         }
 
     }
+    
+    /// Tests use of Context.current.packageDirectory
+    func testPackageContextName() throws {
+        let stream = BufferedOutputByteStream()
+        stream <<< """
+            import PackageDescription
+            let package = Package(name: Context.packageDirectory)
+            """
+
+        loadManifest(stream.bytes) { manifest in
+            let name = parsedManifest?.parentDirectory.pathString ?? ""
+            XCTAssertEqual(manifest.name, name)
+        }
+    }
+
+    /// Tests access to the package's directory contents.
+    func testPackageContextDirectory() throws {
+        let stream = BufferedOutputByteStream()
+        stream <<< """
+            import PackageDescription
+            import Foundation
+            
+            let fileManager = FileManager.default
+            let contents = (try? fileManager.contentsOfDirectory(atPath: Context.packageDirectory)) ?? []
+            let swiftFiles = contents.filter { $0.hasPrefix("TemporaryFile") && $0.hasSuffix(".swift") }
+            
+            let package = Package(name: swiftFiles.joined(separator: ","))
+            """
+
+        loadManifest(stream.bytes) { manifest in
+            let name = parsedManifest?.components.last ?? ""
+            let swiftFiles = manifest.name.split(separator: ",").map(String.init)
+            XCTAssertNotNil(swiftFiles.firstIndex(of: name))
+        }
+    }
 }