Merge pull request swiftlang#31 from benlangmuir/build-system-cleanup1

[build-system] Various minor refactoring and cleanups

Author: benlangmuir

Sources/SKCore/BuildSystem.swift

@@ -11,35 +11,26 @@
 //===----------------------------------------------------------------------===//
 
 import LanguageServerProtocol
+import Basic
 
-/// Provider of build settings.
-public protocol BuildSettingsProvider {
+/// Provider of FileBuildSettings and other build-related information.
+///
+/// The primary role of the build system is to answer queries for FileBuildSettings and (TODO) to
+/// notify clients when they change. The BuildSystem is also the source of related informatino,
+/// such as where the index datastore is located.
+///
+/// For example, a SwiftPMWorkspace provides compiler arguments for the files contained in a
+/// SwiftPM package root directory.
+public protocol BuildSystem {
 
-  /// Returns the settings for the given url and language mode, if known.
-  func settings(for: URL, language: Language) -> FileBuildSettings?
-
-  // TODO: notifications when settings change.
-}
+  /// The path to the raw index store data, if any.
+  var indexStorePath: AbsolutePath? { get }
 
-/// Build settings for a single file.
-public struct FileBuildSettings {
+  /// The path to put the index database, if any.
+  var indexDatabasePath: AbsolutePath? { get }
 
-  /// The identifier of the toolchain that is preferred for compiling this file, if any.
-  public var preferredToolchain: String? = nil
-
-  /// The compiler arguments to use for this file.
-  public var compilerArguments: [String]
-
-  /// The working directory to resolve any relative paths in `compilerArguments`.
-  public var workingDirectory: String? = nil
+  /// Returns the settings for the given url and language mode, if known.
+  func settings(for: URL, _ language: Language) -> FileBuildSettings?
 
-  public init(
-    preferredToolchain: String? = nil,
-    compilerArguments: [String],
-    workingDirectory: String? = nil
-  ) {
-    self.preferredToolchain = preferredToolchain
-    self.compilerArguments = compilerArguments
-    self.workingDirectory = workingDirectory
-  }
+  // TODO: notifications when settings change.
 }

Sources/SKCore/BuildSettingsProviderList.swift renamed to Sources/SKCore/BuildSystemList.swift

@@ -10,21 +10,29 @@
 //
 //===----------------------------------------------------------------------===//
 
+import Basic
 import LanguageServerProtocol
 
-/// Provides build settings from a list of providers in priority order.
-public final class BuildSettingsProviderList: BuildSettingsProvider {
+/// Provides build settings from a list of build systems in priority order.
+public final class BuildSystemList {
 
-  /// The build settings providers to try (in order).
-  public var providers: [BuildSettingsProvider] = [
-    FallbackBuildSettingsProvider()
+  /// The build systems to try (in order).
+  public var providers: [BuildSystem] = [
+    FallbackBuildSystem()
   ]
 
   public init() {}
+}
+
+extension BuildSystemList: BuildSystem {
+
+  public var indexStorePath: AbsolutePath? { return providers.first?.indexStorePath }
+
+  public var indexDatabasePath: AbsolutePath? { return providers.first?.indexDatabasePath }
 
-  public func settings(for url: URL, language: Language) -> FileBuildSettings? {
+  public func settings(for url: URL, _ language: Language) -> FileBuildSettings? {
     for provider in providers {
-      if let settings = provider.settings(for: url, language: language) {
+      if let settings = provider.settings(for: url, language) {
         return settings
       }
     }

Sources/SKCore/CompilationDatabaseBuildSystem.swift

@@ -18,7 +18,7 @@ import LanguageServerProtocol
 ///
 /// Provides build settings from a `CompilationDatabase` found by searching a project. For now, only
 /// one compilation database, located at the project root.
-public final class CompilationDatabaseBuildSystem: BuildSettingsProvider {
+public final class CompilationDatabaseBuildSystem {
 
   /// The compilation database.
   var compdb: CompilationDatabase? = nil
@@ -31,8 +31,15 @@ public final class CompilationDatabaseBuildSystem: BuildSettingsProvider {
       self.compdb = tryLoadCompilationDatabase(directory: path, fileSystem)
     }
   }
+}
+
+extension CompilationDatabaseBuildSystem: BuildSystem {
+
+  // FIXME: derive from the compiler arguments.
+  public var indexStorePath: AbsolutePath? { return nil }
+  public var indexDatabasePath: AbsolutePath? { return nil }
 
-  public func settings(for url: URL, language: Language) -> FileBuildSettings? {
+  public func settings(for url: URL, _ language: Language) -> FileBuildSettings? {
     guard let db = database(for: url),
           let cmd = db[url].first else { return nil }
     return FileBuildSettings(

Sources/SKCore/ExternalWorkspace.swift

@@ -14,34 +14,41 @@ import LanguageServerProtocol
 import Basic
 import enum Utility.Platform
 
-/// A simple build settings provider suitable as a fallback when accurate settings are unknown.
-public final class FallbackBuildSettingsProvider: BuildSettingsProvider {
+/// A simple BuildSystem suitable as a fallback when accurate settings are unknown.
+public final class FallbackBuildSystem: BuildSystem {
 
+  /// The path to the SDK.
   lazy var sdkpath: AbsolutePath? = {
-    if case .darwin? = Platform.currentPlatform {
-      if let str = try? Process.checkNonZeroExit(args: "/usr/bin/xcrun", "--show-sdk-path", "--sdk", "macosx"), let path = try? AbsolutePath(validating: str.spm_chomp()) {
-        return path
-      }
+    if case .darwin? = Platform.currentPlatform,
+       let str = try? Process.checkNonZeroExit(
+         args: "/usr/bin/xcrun", "--show-sdk-path", "--sdk", "macosx"),
+       let path = try? AbsolutePath(validating: str.spm_chomp())
+    {
+      return path
     }
     return nil
   }()
 
-  public func settings(for url: URL, language: Language) -> FileBuildSettings? {
+  public var indexStorePath: AbsolutePath? { return nil }
+
+  public var indexDatabasePath: AbsolutePath? { return nil }
+
+  public func settings(for url: URL, _ language: Language) -> FileBuildSettings? {
     guard let path = try? AbsolutePath(validating: url.path) else {
       return nil
     }
 
     switch language {
     case .swift:
-      return settingsSwift(path: path)
+      return settingsSwift(path)
     case .c, .cpp, .objective_c, .objective_cpp:
-      return settingsClang(path: path, language: language)
+      return settingsClang(path, language)
     default:
       return nil
     }
   }
 
-  func settingsSwift(path: AbsolutePath) -> FileBuildSettings {
+  func settingsSwift(_ path: AbsolutePath) -> FileBuildSettings {
     var args: [String] = []
     if let sdkpath = sdkpath {
       args += [
@@ -53,7 +60,7 @@ public final class FallbackBuildSettingsProvider: BuildSettingsProvider {
     return FileBuildSettings(preferredToolchain: nil, compilerArguments: args)
   }
 
-  func settingsClang(path: AbsolutePath, language: Language) -> FileBuildSettings {
+  func settingsClang(_ path: AbsolutePath, _ language: Language) -> FileBuildSettings {
     var args: [String] = []
     if let sdkpath = sdkpath {
       args += [

Sources/SKCore/FallbackBuildSettingsProvider.swift renamed to Sources/SKCore/FallbackBuildSystem.swift

@@ -0,0 +1,38 @@
+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2014 - 2018 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
+//
+//===----------------------------------------------------------------------===//
+
+/// Build settings for a single file.
+///
+/// Encapsulates all the settings needed to compile a single file, including the compiler arguments,
+/// working directory, and preferred toolchain if any. FileBuildSettings are typically the result
+/// of a BuildSystem query.
+public struct FileBuildSettings {
+
+  /// The identifier of the toolchain that is preferred for compiling this file, if any.
+  public var preferredToolchain: String? = nil
+
+  /// The compiler arguments to use for this file.
+  public var compilerArguments: [String]
+
+  /// The working directory to resolve any relative paths in `compilerArguments`.
+  public var workingDirectory: String? = nil
+
+  public init(
+    preferredToolchain: String? = nil,
+    compilerArguments: [String],
+    workingDirectory: String? = nil)
+  {
+    self.preferredToolchain = preferredToolchain
+    self.compilerArguments = compilerArguments
+    self.workingDirectory = workingDirectory
+  }
+}

Sources/SKCore/FileBuildSettings.swift

@@ -40,7 +40,7 @@ public final class SwiftPMWorkspace {
   var fileToTarget: [AbsolutePath: TargetBuildDescription] = [:]
   var sourceDirToTarget: [AbsolutePath: TargetBuildDescription] = [:]
 
-  /// Creates a `BuildSettingsProvider` using the Swift Package Manager, if this workspace is part of a package.
+  /// Creates a `BuildSystem` using the Swift Package Manager, if this workspace is part of a package.
   ///
   /// - returns: nil if `workspacePath` is not part of a package or there is an error.
   public convenience init?(url: LanguageServerProtocol.URL, toolchainRegistry: ToolchainRegistry) {
@@ -52,7 +52,7 @@ public final class SwiftPMWorkspace {
     }
   }
 
-  /// Creates a `BuildSettingsProvider` using the Swift Package Manager, if this workspace is part of a package.
+  /// Creates a `BuildSystem` using the Swift Package Manager, if this workspace is part of a package.
   ///
   /// - returns: nil if `workspacePath` is not part of a package.
   /// - throws: If there is an error loading the package.
@@ -163,9 +163,7 @@ public final class SwiftPMWorkspace {
   }
 }
 
-extension SwiftPMWorkspace: ExternalWorkspace, BuildSettingsProvider {
-
-  public var buildSystem: BuildSettingsProvider { return self }
+extension SwiftPMWorkspace: BuildSystem {
 
   public var buildPath: AbsolutePath {
     return buildParameters.buildPath
@@ -179,21 +177,24 @@ extension SwiftPMWorkspace: ExternalWorkspace, BuildSettingsProvider {
     return buildPath.appending(components: "index", "db")
   }
 
-  public func settings(for url: LanguageServerProtocol.URL, language: Language) -> FileBuildSettings? {
+  public func settings(
+    for url: LanguageServerProtocol.URL,
+    _ language: Language) -> FileBuildSettings?
+  {
     guard let path = try? AbsolutePath(validating: url.path) else {
       return nil
     }
 
     if let td = self.fileToTarget[path] {
-      return settings(for: path, language: language, targetDescription: td)
+      return settings(for: path, language, td)
     }
 
     if path.basename == "Package.swift" {
       return packageDescriptionSettings(path)
     }
 
     if path.extension == "h" {
-      return settings(forHeader: path, language: language)
+      return settings(forHeader: path, language)
     }
 
     return nil
@@ -206,8 +207,8 @@ extension SwiftPMWorkspace {
 
   public func settings(
     for path: AbsolutePath,
-    language: Language,
-    targetDescription td: TargetBuildDescription
+    _ language: Language,
+    _ td: TargetBuildDescription
   ) -> FileBuildSettings? {
 
     let buildPath = self.buildPath
@@ -315,11 +316,11 @@ extension SwiftPMWorkspace {
     return nil
   }
 
-  public func settings(forHeader path: AbsolutePath, language: Language) -> FileBuildSettings? {
+  public func settings(forHeader path: AbsolutePath, _ language: Language) -> FileBuildSettings? {
     var dir = path.parentDirectory
     while !dir.isRoot {
       if let td = sourceDirToTarget[dir] {
-        return settings(for: path, language: language, targetDescription: td)
+        return settings(for: path, language, td)
       }
       dir = dir.parentDirectory
     }