Rescue graph building test into subcommand

Sources/dpk-cli/CommandLine.swift

@@ -16,6 +16,7 @@ struct DarwinApkCLI: AsyncParsableCommand {
       DpkUpdateCommand.self,
       DpkUpgradeCommand.self,
       DpkSearchCommand.self,
-      DpkInfoCommand.self
+      DpkInfoCommand.self,
+      DpkGraphCommand.self
     ])
 }

Sources/dpk-cli/Subcommands/DpkGraphCommand.swift

@@ -0,0 +1,32 @@
+/*
+ * darwin-apk © 2024 Gay Pizza Specifications
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+import Foundation
+import ArgumentParser
+import darwin_apk
+
+struct DpkGraphCommand: AsyncParsableCommand {
+  static let configuration = CommandConfiguration(commandName: "graph")
+
+  func run() async throws(ExitCode) {
+    let graph: ApkPackageGraph
+    do {
+      let localRepositories = try await ApkRepositoriesConfig()
+      graph = ApkPackageGraph(index: try await ApkIndexReader.resolve(localRepositories.repositories, fetch: .lazy))
+      graph.buildGraphNode()
+
+      try graph.pkgIndex.description.write(to: URL(filePath: "packages.txt"), atomically: false, encoding: .utf8)
+    } catch {
+      fatalError(error.localizedDescription)
+    }
+
+    if var out = TextFileWriter(URL(filePath: "shallowIsolates.txt")) {
+      for node in graph.shallowIsolates { print(node, to: &out) }
+    }
+    if var out = TextFileWriter(URL(filePath: "deepIsolates.txt")) {
+      for node in graph.deepIsolates { print(node, to: &out) }
+    }
+  }
+}

Sources/dpk-cli/TextFileWriter.swift

@@ -0,0 +1,29 @@
+/*
+ * darwin-apk © 2024 Gay Pizza Specifications
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+import Foundation
+import Darwin
+
+struct TextFileWriter: TextOutputStream {
+  private var _hnd: FileHandle
+
+  init?(_ to: URL) {
+    let file = open(to.path(), O_WRONLY | O_CREAT | O_TRUNC | O_SYNC, 0o644)
+    guard file >= 0 else {
+      return nil
+    }
+    self._hnd = FileHandle(fileDescriptor: file, closeOnDealloc: true)
+  }
+
+  mutating func write(_ string: String) {
+    if let data = string.data(using: .utf8) {
+      try? self._hnd.write(contentsOf: data)
+    }
+  }
+
+  mutating func close() throws {
+    try self._hnd.close()
+  }
+}