BazelBuildServiceStub.swift

/*
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   this list of conditions and the following disclaimer in the documentation
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of the authors and should not be interpreted as representing official policies,
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*/

import Foundation
import BKBuildService

// TODO:
// - decompose the "Bazel" example to work end to end with Xcode
// - hardcode DeriveData /private/var/tmp/xcbuildkit/example-dd or read
// - read workspace from xcbuild / remove jmarino
// - for this example - have another program generate the index and verify it
//   works
let clangXMLT: String = """
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<array>
        <dict>
                <key>LanguageDialect</key>
                <string>objective-c</string>
                <key>clangASTBuiltProductsDir</key>
                <string>__DERIVED_DATA_PATH__/__WORKSPACE_NAME__-__WORKSPACE_HASH__/Index/Build/Products/__CONFIGURATION__-__PLATFORM__</string>
                <key>clangASTCommandArguments</key>
                <array>
                        __CMD_LINE_ARGS__
                        <string>-working-directory</string>
                        <string>__WORKING_DIR__</string>
                        <string>-fsyntax-only</string>
                        <string>__SOURCE_FILE__</string>
                </array>
                <key>outputFilePath</key>
                <string>__OUTPUT_FILE_PATH__</string>
                <key>sourceFilePath</key>
                <string>__SOURCE_FILE__</string>
                <key>toolchains</key>
                <array>
                        <string>com.apple.dt.toolchain.XcodeDefault</string>
                </array>
        </dict>
</array>
</plist>
"""

let swiftXMLT: String = """
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
	<array>
		<dict>
                        <key>LanguageDialect</key>
                        <string>swift</string>
                        <key>outputFilePath</key>
                        <string>__OUTPUT_FILE_PATH__</string>
                        <key>sourceFilePath</key>
                        <string>__SOURCE_FILE__</string>
                        <key>swiftASTBuiltProductsDir</key>
                        <string>__DERIVED_DATA_PATH__/__WORKSPACE_NAME__-__WORKSPACE_HASH__/Index/Build/Products/__CONFIGURATION__-__PLATFORM__</string>
                        <key>swiftASTCommandArguments</key>
                        <array>
                                __CMD_LINE_ARGS__
                                <string>-working-directory</string>
                                <string>__WORKING_DIR__</string>
                        </array>
                        <key>swiftASTModuleName</key>
                        <string>__MODULE_NAME__</string>
                        <key>toolchains</key>
                        <array>
                                <string>com.apple.dt.toolchain.XcodeDefault</string>
                        </array>
		</dict>
	</array>
</plist>
"""

public enum BazelBuildServiceStub {
        static private func xmlFromCmdLineArgs(args: [String], defaultWorkingDir: String) -> String {
                return args
                .map {
                        if $0.hasSuffix(".swift") {
                                return String("<string>\(defaultWorkingDir)/\($0)</string>")
                        }

                        return String("<string>\($0)</string>")
                }
                .joined(separator: "\n")
        }

        static private func collectValueForCompilerFlag(name: String, cmdLineArgs: [String]) -> String? {
                guard cmdLineArgs.count > 0 else { return nil }

                var collectNext: Bool = false
                for arg in cmdLineArgs {
                        if arg == name {
                                collectNext = true
                                continue
                        } else if collectNext {
                                return arg
                        }
                }
                return nil
        }

        public static func getASTArgs(isSwift: Bool,
                                      targetID: String,
                                      xcode: String,
                                      sourceFilePath: String,
                                      outputFilePath: String,
                                      derivedDataPath: String,
                                      workspaceHash: String,
                                      workspaceName: String,
                                      sdkPath: String,
                                      sdkName: String,
                                      defaultWorkingDir: String,
                                      bazelWorkingDir: String?,
                                      configuration: String,
                                      platform: String,
                                      cmdLineArgs: [String]) -> Data {
                var stub = isSwift ? swiftXMLT : clangXMLT
                let workingDir = bazelWorkingDir ?? defaultWorkingDir
                let cmdLineArgsXML = BazelBuildServiceStub.xmlFromCmdLineArgs(args: cmdLineArgs, defaultWorkingDir: defaultWorkingDir)

                stub = stub.replacingOccurrences(of:"__CMD_LINE_ARGS__", with: cmdLineArgsXML)
                .replacingOccurrences(of:"__SOURCE_FILE__", with: sourceFilePath)
                .replacingOccurrences(of:"__OUTPUT_FILE_PATH__", with: outputFilePath)
                .replacingOccurrences(of:"__WORKSPACE_NAME__", with: workspaceName)
                .replacingOccurrences(of:"__DERIVED_DATA_PATH__", with: derivedDataPath)
                .replacingOccurrences(of:"__WORKSPACE_HASH__", with: workspaceHash)
                .replacingOccurrences(of:"__BAZEL_XCODE_SDKROOT__", with: sdkPath)
                .replacingOccurrences(of:"__WORKING_DIR__", with: workingDir)
                .replacingOccurrences(of:"__CONFIGURATION__", with: configuration)
                .replacingOccurrences(of:"__PLATFORM__", with: platform)
                .replacingOccurrences(of:"__BAZEL_XCODE_DEVELOPER_DIR__", with: "\(xcode)/Contents/Developer")

                // Extracts value of `-module-name` from `swiftc` flags to set in the plist
                if let moduleName = BazelBuildServiceStub.collectValueForCompilerFlag(name: "-module-name", cmdLineArgs: cmdLineArgs), isSwift {
                        stub = stub.replacingOccurrences(of:"__MODULE_NAME__", with: moduleName)
                }

                // When indexing is setting up the data store it fails if compiler flags contain relative paths
                // Fixes that by pre-pending the working directory, we might want to revisit this and fix it
                // earlier in the build (i.e. when generating the compiler flags via an aspect)
                //
                // Example of what this does:
                //
                // -ivfsoverlaybazel-out/path/to/foo.yaml => -ivfsoverlay/private/var/path/to/execution_root/<workspace>/bazel-out/path/to/foo.yaml
                stub = stub.replacingOccurrences(of:"bazel-out/", with: "\(workingDir)/bazel-out/")
                // For indexing to work the path to the output file has to be relative to the `-working-directory` flag
                // so undo what the line above did only for this artifact
                stub = stub.replacingOccurrences(of: "\(workingDir)/\(outputFilePath)", with: outputFilePath)

                return BPlistConverter(xml: stub)?.convertToBinary() ?? Data()
        }

        // Required if `outputPathOnly` is `true` in the indexing request
        public static func outputPathOnlyData(outputFilePath: String,
                                              sourceFilePath: String,
                                              workingDir: String,
                                              bazelWorkingDir: String?) -> Data {
                let xml = """
                <!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
                <plist version="1.0">
                <array>
                        <dict>
                        <key>outputFilePath</key>
                        <string>\(outputFilePath)</string>
                        <key>sourceFilePath</key>
                        <string>\(sourceFilePath)</string>
                        </dict>
                </array>
                </plist>
                """
                guard let converter = BPlistConverter(xml: xml) else {
                        fatalError("Failed to allocate converter")
                }
                guard let bplistData = converter.convertToBinary() else {
                        fatalError("Failed to convert XML to binary plist data")
                }

                return bplistData
        }
}