Add support for looking up spec resources in a toolchain install

Author: owenv

Package.swift

@@ -45,7 +45,8 @@ func swiftSettings(languageMode: SwiftLanguageMode) -> [SwiftSetting] {
 
             .swiftLanguageMode(.v5),
 
-            .define("USE_STATIC_PLUGIN_INITIALIZATION")
+            .define("USE_STATIC_PLUGIN_INITIALIZATION"),
+            .define("SEARCH_TOOLCHAIN_FOR_RESOURCES")
         ]
     case .v6:
         return [
@@ -55,7 +56,8 @@ func swiftSettings(languageMode: SwiftLanguageMode) -> [SwiftSetting] {
 
             .swiftLanguageMode(.v6),
 
-            .define("USE_STATIC_PLUGIN_INITIALIZATION")
+            .define("USE_STATIC_PLUGIN_INITIALIZATION"),
+            .define("SEARCH_TOOLCHAIN_FOR_RESOURCES")
         ]
     default:
         fatalError("unexpected language mode")

Sources/SWBAndroidPlatform/Plugin.swift

@@ -25,7 +25,7 @@ import Foundation
 
 struct AndroidPlatformSpecsExtension: SpecificationsExtension {
     func specificationFiles() -> Bundle? {
-        .module
+        findResourceBundle(nameWhenInstalledInToolchain: "SwiftBuild_SWBAndroidPlatform", defaultBundle: Bundle.module)
     }
 
     func specificationDomains() -> [String : [String]] {

Sources/SWBApplePlatform/Plugin.swift

@@ -99,7 +99,7 @@ struct ApplePlatformSpecsExtension: SpecificationsExtension {
     }
 
     func specificationFiles() -> Bundle? {
-        .module
+        findResourceBundle(nameWhenInstalledInToolchain: "SwiftBuild_SWBApplePlatform", defaultBundle: Bundle.module)
     }
 
     func specificationDomains() -> [String : [String]] {

Sources/SWBCore/Extensions/SpecificationsExtension.swift

@@ -69,4 +69,22 @@ extension SpecificationsExtension {
     public func specificationClassesClassic() -> [any SpecClassType.Type] { [] }
     public func specificationImplementations() -> [any SpecImplementationType.Type] { [] }
     public func specificationSearchPaths() -> [URL] { [] }
+
+    public func findResourceBundle(nameWhenInstalledInToolchain: String, defaultBundle: Bundle?) -> Bundle? {
+        #if SEARCH_TOOLCHAIN_FOR_RESOURCES
+        let resourceBundleExtension: String
+        #if canImport(Darwin)
+        resourceBundleExtension = "bundle"
+        #else
+        resourceBundleExtension = "resources"
+        #endif
+        if let executablePath = try? Path(CommandLine.arguments[0]).resolveSymlink(fs: localFS) {
+            let prospectiveBundlePath = executablePath.dirname.dirname.join("share").join("pm").join("\(nameWhenInstalledInToolchain).\(resourceBundleExtension)")
+            if let bundle = Bundle(path: prospectiveBundlePath.str) {
+                return bundle
+            }
+        }
+        #endif
+        return defaultBundle
+    }
 }

Sources/SWBCore/SpecImplementations/RegisterSpecs.swift

@@ -144,6 +144,6 @@ public struct BuiltinSpecsExtension: SpecificationsExtension {
     }
 
     public func specificationFiles() -> Bundle? {
-        .module
+        findResourceBundle(nameWhenInstalledInToolchain: "SwiftBuild_SWBCore", defaultBundle: Bundle.module)
     }
 }

Sources/SWBGenericUnixPlatform/Plugin.swift

@@ -20,7 +20,7 @@ import Foundation
 
 struct GenericUnixPlatformSpecsExtension: SpecificationsExtension {
     func specificationFiles() -> Bundle? {
-        .module
+        findResourceBundle(nameWhenInstalledInToolchain: "SwiftBuild_SWBGenericUnixPlatform", defaultBundle: Bundle.module)
     }
 
     func specificationDomains() -> [String: [String]] {

Sources/SWBQNXPlatform/Plugin.swift

@@ -25,7 +25,7 @@ import Foundation
 
 struct QNXPlatformSpecsExtension: SpecificationsExtension {
     func specificationFiles() -> Bundle? {
-        .module
+        findResourceBundle(nameWhenInstalledInToolchain: "SwiftBuild_SWBQNXPlatform", defaultBundle: Bundle.module)
     }
 }
 

Sources/SWBUniversalPlatform/Plugin.swift

@@ -36,11 +36,11 @@ struct UniversalPlatformSpecsExtension: SpecificationsExtension {
     }
 
     func specificationFiles() -> Bundle? {
-        .module
+        findResourceBundle(nameWhenInstalledInToolchain: "SwiftBuild_SWBUniversalPlatform", defaultBundle: Bundle.module)
     }
 
     // Allow locating the sole remaining `.xcbuildrules` file.
     func specificationSearchPaths() -> [URL] {
-        Bundle.module.resourceURL.map { [$0] } ?? []
+        findResourceBundle(nameWhenInstalledInToolchain: "SwiftBuild_SWBUniversalPlatform", defaultBundle: Bundle.module)?.resourceURL.map { [$0] } ?? []
     }
 }

Sources/SWBWebAssemblyPlatform/Plugin.swift

@@ -23,7 +23,7 @@ import Foundation
 
 struct WebAssemblyPlatformSpecsExtension: SpecificationsExtension {
     func specificationFiles() -> Bundle? {
-        .module
+        findResourceBundle(nameWhenInstalledInToolchain: "SwiftBuild_SWBWebAssemblyPlatform", defaultBundle: Bundle.module)
     }
 }
 

Sources/SWBWindowsPlatform/Plugin.swift

@@ -21,7 +21,7 @@ import Foundation
 
 struct WindowsPlatformSpecsExtension: SpecificationsExtension {
     func specificationFiles() -> Bundle? {
-        .module
+        findResourceBundle(nameWhenInstalledInToolchain: "SwiftBuild_SWBWindowsPlatform", defaultBundle: Bundle.module)
     }
 }