Support exposing enums from ObjC via Bridging headers

README.md

@@ -267,6 +267,41 @@ That command creates an empty file on a remote server which informs that for giv
 
 _Note that for the `producer` mode, the prebuild build phase and `xccc`, `xcld`, `xclibtool` wrappers become no-op, so it is recommended to not add them for the `producer` mode._
 
+##### 7. Generalize `-Swift.h` (Optional only if using static library with a bridging header with public `NS_ENUM` exposed from ObjC)
+
+If a static library target contains a mixed target with a bridging header exposing an enum from ObjC in a public Swift API, your custom script that moves `*-Swift.h` to the shared location, it should also move `*-Swift.h.md5` next to it.
+
+Example:
+
+##### Existing script (Before):
+
+```shell
+ditto "${SCRIPT_INPUT_FILE_0}" "${SCRIPT_OUTPUT_FILE_0}"
+```
+
+where
+* `SCRIPT_INPUT_FILE_0="$(DERIVED_SOURCES_DIR)/$(SWIFT_OBJC_INTERFACE_HEADER_NAME)"`
+* `SCRIPT_OUTPUT_FILE_0="$(BUILT_PRODUCTS_DIR)/include/$(PRODUCT_MODULE_NAME)/$(SWIFT_OBJC_INTERFACE_HEADER_NAME)"`
+
+##### Correct script (After):
+
+```shell
+ditto "${SCRIPT_INPUT_FILE_0}" "${SCRIPT_OUTPUT_FILE_0}"
+[ -f "${SCRIPT_INPUT_FILE_1}" ] && ditto "${SCRIPT_INPUT_FILE_1}" "${SCRIPT_OUTPUT_FILE_1}" || rm "${SCRIPT_OUTPUT_FILE_1}"
+```
+
+where
+* `SCRIPT_INPUT_FILE_0="$(DERIVED_SOURCES_DIR)/$(SWIFT_OBJC_INTERFACE_HEADER_NAME)"`
+* `SCRIPT_INPUT_FILE_1="$(DERIVED_SOURCES_DIR)/$(SWIFT_OBJC_INTERFACE_HEADER_NAME).md5"`
+* `SCRIPT_OUTPUT_FILE_0="$(BUILT_PRODUCTS_DIR)/include/$(PRODUCT_MODULE_NAME)/$(SWIFT_OBJC_INTERFACE_HEADER_NAME)"`
+* `SCRIPT_OUTPUT_FILE_1="$(BUILT_PRODUCTS_DIR)/include/$(PRODUCT_MODULE_NAME)/$(SWIFT_OBJC_INTERFACE_HEADER_NAME).md5"`
+
+Note: This step is not required if at least one of these is true:
+
+* you build a framework (not a static library)
+* you don't expose `NS_ENUM` type from ObjC to Swift via a bridging header
+
+
 ## A full list of configuration parameters:
 
 | Property | Description | Default | Required |

Sources/XCRemoteCache/Artifacts/ArtifactCreator.swift

@@ -42,6 +42,7 @@ class BuildArtifactCreator: ArtifactSwiftProductsBuilderImpl, ArtifactCreator {
     private let modulesFolderPath: String
     private let dSYMPath: URL
     private let metaWriter: MetaWriter
+    private let artifactProcessor: ArtifactProcessor
     private let fileManager: FileManager
 
     init(
@@ -52,6 +53,7 @@ class BuildArtifactCreator: ArtifactSwiftProductsBuilderImpl, ArtifactCreator {
         modulesFolderPath: String,
         dSYMPath: URL,
         metaWriter: MetaWriter,
+        artifactProcessor: ArtifactProcessor,
         fileManager: FileManager
     ) {
         self.buildDir = buildDir
@@ -62,6 +64,7 @@ class BuildArtifactCreator: ArtifactSwiftProductsBuilderImpl, ArtifactCreator {
         self.fileManager = fileManager
         self.dSYMPath = dSYMPath
         self.metaWriter = metaWriter
+        self.artifactProcessor = artifactProcessor
         super.init(workingDir: tempDir, moduleName: moduleName, fileManager: fileManager)
     }
 
@@ -87,6 +90,7 @@ class BuildArtifactCreator: ArtifactSwiftProductsBuilderImpl, ArtifactCreator {
     /// - Parameter tempDir: Temp location to organize file hierarchy in the artifact
     /// - returns: URLs to include into the artifact package
     fileprivate func prepareSwiftArtifacts(tempDir: URL) throws -> [URL] {
+        try artifactProcessor.process(localArtifact: tempDir)
         var artifacts: [URL] = []
 
         // Add optional directory with generated ObjC headers

Sources/XCRemoteCache/Artifacts/ArtifactOrganizer.swift

@@ -31,7 +31,7 @@ enum ArtifactOrganizerLocationPreparationResult: Equatable {
     case preparedForArtifact(artifact: URL)
 }
 
-/// Prepares .zip artifact for the local operations
+/// Prepares existing .zip artifact for the local operations
 protocol ArtifactOrganizer {
     /// Prepares the location for the artifact unzipping
     /// - Parameter fileKey: artifact fileKey that corresponds to the zip filename on the remote cache server
@@ -48,10 +48,13 @@ protocol ArtifactOrganizer {
 
 class ZipArtifactOrganizer: ArtifactOrganizer {
     private let cacheDir: URL
+    // all processors that should "prepare" the unzipped raw artifact
+    private let artifactProcessors: [ArtifactProcessor]
     private let fileManager: FileManager
 
-    init(targetTempDir: URL, fileManager: FileManager) {
+    init(targetTempDir: URL, artifactProcessors: [ArtifactProcessor], fileManager: FileManager) {
         cacheDir = targetTempDir.appendingPathComponent("xccache")
+        self.artifactProcessors = artifactProcessors
         self.fileManager = fileManager
     }
 
@@ -93,6 +96,10 @@ class ZipArtifactOrganizer: ArtifactOrganizer {
         // when the command was interrupted (internal crash or `kill -9` signal)
         let tempDestination = destinationURL.appendingPathExtension("tmp")
         try Zip.unzipFile(artifact, destination: tempDestination, overwrite: true, password: nil)
+
+        try artifactProcessors.forEach { processor in
+            try processor.process(rawArtifact: tempDestination)
+        }
         try fileManager.moveItem(at: tempDestination, to: destinationURL)
         return destinationURL
     }

Sources/XCRemoteCache/Artifacts/ArtifactProcessor.swift

@@ -0,0 +1,80 @@
+// Copyright (c) 2022 Spotify AB.
+//
+// Licensed to the Apache Software Foundation (ASF) under one
+// or more contributor license agreements.  See the NOTICE file
+// distributed with this work for additional information
+// regarding copyright ownership.  The ASF licenses this file
+// to you under the Apache License, Version 2.0 (the
+// "License"); you may not use this file except in compliance
+// with the License.  You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing,
+// software distributed under the License is distributed on an
+// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+// KIND, either express or implied.  See the License for the
+// specific language governing permissions and limitations
+// under the License.
+
+import Foundation
+
+
+/// Performs a pre/postprocessing on an artifact package
+/// Could be a place for file reorganization (to support legacy package formats) and/or
+/// remapp absolute paths in some package files
+protocol ArtifactProcessor {
+    /// Processes a raw artifact in a directory. Raw artifact is a format of an artifact
+    /// that is stored in a remote cache server (generic)
+    /// - Parameter rawArtifact: directory that contains raw artifact content
+    func process(rawArtifact: URL) throws
+
+    /// Processes a local artifact in a directory
+    /// - Parameter localArtifact: directory that contains local (machine-specific) artifact content
+    func process(localArtifact: URL) throws
+}
+
+/// Processes downloaded artifact by replacing generic paths in generated ObjC headers placed in ./include
+class UnzippedArtifactProcessor: ArtifactProcessor {
+    /// All directories in an artifact that should be processed by path remapping
+    private static let remappingDirs = ["include"]
+    private let fileRemapper: FileDependenciesRemapper
+    private let dirScanner: DirScanner
+
+    init(fileRemapper: FileDependenciesRemapper, dirScanner: DirScanner) {
+        self.fileRemapper = fileRemapper
+        self.dirScanner = dirScanner
+    }
+
+    private func findProcessingEligableFiles(path: String) throws -> [URL] {
+        let remappingURL = URL(fileURLWithPath: path)
+        let allFiles = try dirScanner.recursiveItems(at: remappingURL)
+        return allFiles.filter({ !$0.isHidden })
+    }
+
+    /// Replaces all generic paths in a raw artifact's `include` dir with
+    /// absolute paths, specific for a given machine and configuration
+    /// - Parameter rawArtifact: raw artifact location
+    func process(rawArtifact url: URL) throws {
+        for remappingDir in Self.remappingDirs {
+            let remappingPath = url.appendingPathComponent(remappingDir).path
+            let allFiles = try findProcessingEligableFiles(path: remappingPath)
+            try allFiles.forEach(fileRemapper.remap(fromGeneric:))
+        }
+    }
+
+    func process(localArtifact url: URL) throws {
+        for remappingDir in Self.remappingDirs {
+            let remappingPath = url.appendingPathComponent(remappingDir).path
+            let allFiles = try findProcessingEligableFiles(path: remappingPath)
+            try allFiles.forEach(fileRemapper.remap(fromLocal:))
+        }
+    }
+}
+
+fileprivate extension URL {
+    // Recognize hidden files starting with a dot
+    var isHidden: Bool {
+        lastPathComponent.hasPrefix(".")
+    }
+}

Sources/XCRemoteCache/Artifacts/ArtifactSwiftProductsBuilder.swift

@@ -88,7 +88,7 @@ class ArtifactSwiftProductsBuilderImpl: ArtifactSwiftProductsBuilder {
             throw ArtifactSwiftProductsBuilderError.populatingNonExistingObjCHeader
         }
         try fileManager.createDirectory(at: moduleObjCURL, withIntermediateDirectories: true, attributes: nil)
-        try fileManager.spt_forceLinkItem(at: headerURL, to: headerArtifactURL)
+        try fileManager.spt_forceCopyItem(at: headerURL, to: headerArtifactURL)
     }
 
     func includeModuleDefinitionsToTheArtifact(arch: String, moduleURL: URL) throws {

Sources/XCRemoteCache/Artifacts/FileDependenciesRemapper.swift

@@ -0,0 +1,81 @@
+// Copyright (c) 2022 Spotify AB.
+//
+// Licensed to the Apache Software Foundation (ASF) under one
+// or more contributor license agreements.  See the NOTICE file
+// distributed with this work for additional information
+// regarding copyright ownership.  The ASF licenses this file
+// to you under the Apache License, Version 2.0 (the
+// "License"); you may not use this file except in compliance
+// with the License.  You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing,
+// software distributed under the License is distributed on an
+// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+// KIND, either express or implied.  See the License for the
+// specific language governing permissions and limitations
+// under the License.
+
+import Foundation
+
+
+enum FileDependenciesRemapperError: Error {
+    /// Thrown when the file to remap is invalid (e.g. doesn't exist or has unexpected format)
+    case invalidRemappingFile(URL)
+}
+
+/// Replaces paths in a file content between generic (placeholder-based)
+/// and local formats
+protocol FileDependenciesRemapper {
+    /// Replaces all generic paths (with placeholders) to a local, machine
+    /// specific absolute paths
+    /// - Parameter url: location of a file that should be remapped in-place
+    func remap(fromGeneric url: URL) throws
+    /// Replaces all local, machine specific absolute paths to
+    /// generic ones
+    /// - Parameter url: location of a file that should be remapped in-place
+    func remap(fromLocal url: URL) throws
+}
+
+/// Remaps absolute paths in a text files stored on a disk
+/// Note: That class can be used only for text-based files, not binaries
+class TextFileDependenciesRemapper: FileDependenciesRemapper {
+    private static let linesSeparator = "\n"
+    private let remapper: DependenciesRemapper
+    private let fileAccessor: FileAccessor
+
+    init(remapper: DependenciesRemapper, fileAccessor: FileAccessor) {
+        self.remapper = remapper
+        self.fileAccessor = fileAccessor
+    }
+
+    private func readFileLines(_ url: URL) throws -> [String] {
+        guard let content = try fileAccessor.contents(atPath: url.path) else {
+            // the file is empty
+            return []
+        }
+        guard let contentString = String(data: content, encoding: .utf8) else {
+            throw FileDependenciesRemapperError.invalidRemappingFile(url)
+        }
+        return contentString.components(separatedBy: .newlines)
+    }
+
+    private func storeFileLines(lines: [String], url: URL) throws {
+        let contentString = lines.joined(separator: "\n")
+        let contentData = contentString.data(using: String.Encoding.utf8)
+        try fileAccessor.write(toPath: url.path, contents: contentData)
+    }
+
+    func remap(fromGeneric url: URL) throws {
+        let contentLines = try readFileLines(url)
+        let remappedContent = try remapper.replace(genericPaths: contentLines)
+        try storeFileLines(lines: remappedContent, url: url)
+    }
+
+    func remap(fromLocal url: URL) throws {
+        let contentLines = try readFileLines(url)
+        let remappedContent = try remapper.replace(localPaths: contentLines)
+        try storeFileLines(lines: remappedContent, url: url)
+    }
+}

Sources/XCRemoteCache/Commands/Plugins/Thinning/Factories/ThinningConsumerArtifactsOrganizerFactory.swift

@@ -27,13 +27,19 @@ protocol ThinningConsumerArtifactsOrganizerFactory {
 }
 
 class ThinningConsumerZipArtifactsOrganizerFactory: ThinningConsumerArtifactsOrganizerFactory {
+    private let processors: [ArtifactProcessor]
     private let fileManager: FileManager
 
-    init(fileManager: FileManager) {
+    init(processors: [ArtifactProcessor], fileManager: FileManager) {
+        self.processors = processors
         self.fileManager = fileManager
     }
 
     func build(targetTempDir: URL) -> ArtifactOrganizer {
-        ZipArtifactOrganizer(targetTempDir: targetTempDir, fileManager: fileManager)
+        ZipArtifactOrganizer(
+            targetTempDir: targetTempDir,
+            artifactProcessors: processors,
+            fileManager: fileManager
+        )
     }
 }

Sources/XCRemoteCache/Commands/Plugins/Thinning/ThinningDiskSwiftcProductsGenerator.swift

@@ -58,7 +58,7 @@ class ThinningDiskSwiftcProductsGenerator: SwiftcProductsGenerator {
     func generateFrom(
         artifactSwiftModuleFiles sourceAtifactSwiftModuleFiles: [SwiftmoduleFileExtension: URL],
         artifactSwiftModuleObjCFile: URL
-    ) throws -> URL {
+    ) throws -> SwiftcProductsGeneratorOutput {
         // Move cached -Swift.h file to the expected location
         try diskCopier.copy(file: artifactSwiftModuleObjCFile, destination: objcHeaderOutput)
         for (ext, url) in sourceAtifactSwiftModuleFiles {
@@ -79,6 +79,9 @@ class ThinningDiskSwiftcProductsGenerator: SwiftcProductsGenerator {
         }
 
         // Build parent dir of the .swiftmodule file that contains a module
-        return modulePathOutput.deletingLastPathComponent()
+        return SwiftcProductsGeneratorOutput(
+            swiftmoduleDir: modulePathOutput.deletingLastPathComponent(),
+            objcHeaderFile: objcHeaderOutput
+        )
     }
 }

Sources/XCRemoteCache/Commands/Plugins/Thinning/UnzippedArtifactSwiftProductsOrganizer.swift

@@ -73,11 +73,12 @@ class UnzippedArtifactSwiftProductsOrganizer: SwiftProductsOrganizer {
             .appendingPathComponent(moduleName)
             .appendingPathComponent("\(moduleName)-Swift.h")
 
-        let generatedModuleDir = try productsGenerator.generateFrom(
+        let generatedModule = try productsGenerator.generateFrom(
             artifactSwiftModuleFiles: artifactSwiftmoduleFiles,
             artifactSwiftModuleObjCFile: artifactSwiftModuleObjCFile
         )
 
-        try fingerprintSyncer.decorate(sourceDir: generatedModuleDir, fingerprint: fingerprint)
+        try fingerprintSyncer.decorate(sourceDir: generatedModule.swiftmoduleDir, fingerprint: fingerprint)
+        try fingerprintSyncer.decorate(file: generatedModule.objcHeaderFile, fingerprint: fingerprint)
     }
 }

Sources/XCRemoteCache/Commands/Postbuild/Postbuild.swift

@@ -238,13 +238,32 @@ class Postbuild {
         let moduleSwiftProductURL = context.productsDir
             .appendingPathComponent(context.modulesFolderPath)
             .appendingPathComponent("\(modulename).swiftmodule")
+        let objcHeaderSwiftProductURL = context.derivedSourcesDir
+            .appendingPathComponent("\(modulename)-Swift.h")
+        // This header is obly valid if building a frameworks
+        let objcHeaderSwiftPublicPathURL = context.publicHeadersFolderPath?
+            .appendingPathComponent("\(modulename)-Swift.h")
         if let fingerprint = contextSpecificFingerprint {
             try fingerprintSyncer.decorate(
                 sourceDir: moduleSwiftProductURL,
                 fingerprint: fingerprint
             )
+            try fingerprintSyncer.decorate(
+                file: objcHeaderSwiftProductURL,
+                fingerprint: fingerprint
+            )
+            if let objcPublic = objcHeaderSwiftPublicPathURL {
+                try fingerprintSyncer.decorate(
+                    file: objcPublic,
+                    fingerprint: fingerprint
+                )
+            }
         } else {
             try fingerprintSyncer.delete(sourceDir: moduleSwiftProductURL)
+            try fingerprintSyncer.delete(sourceDir: objcHeaderSwiftProductURL)
+            if let objcPublic = objcHeaderSwiftPublicPathURL {
+                try fingerprintSyncer.delete(file: objcPublic)
+            }
         }
     }
 }