Renamed to cli version.

Sources/CliVersion/GitVersionClient.swift

@@ -0,0 +1,164 @@
+import Foundation
+#if canImport(FoundationNetworking)
+  import FoundationNetworking
+#endif
+import ShellClient
+import XCTestDynamicOverlay
+
+/// A client that can retrieve the current version from a git directory.
+/// It will use the current `tag`, or if the current git tree does not
+/// point to a commit that is tagged, it will use the `branch git-sha` as
+/// the version.
+///
+/// This is often not used directly, instead it is used with one of the plugins
+/// that is supplied with this library.  The use case is to set the version of a command line
+/// tool based on the current git tag.
+///
+public struct GitVersionClient {
+
+  /// The closure to run that returns the current version from a given
+  /// git directory.
+  private var currentVersion: (String?) throws -> String
+
+  /// Create a new ``GitVersionClient`` instance.
+  ///
+  /// This is normally not interacted with directly, instead access the client through the dependency system.
+  /// ```swift
+  /// @Dependency(\.gitVersionClient)
+  /// ```
+  ///
+  /// - Parameters:
+  ///   - currentVersion: The closure that returns the current version.
+  ///
+  public init(currentVersion: @escaping (String?) throws -> String) {
+    self.currentVersion = currentVersion
+  }
+
+  /// Get the current version from the `git tag` in the given directory.
+  /// If a directory is not passed in, then we will use the current working directory.
+  ///
+  /// - Parameters:
+  ///   - gitDirectory: The directory to run the command in.
+  public func currentVersion(in gitDirectory: String? = nil) throws -> String {
+    try self.currentVersion(gitDirectory)
+  }
+
+  /// Override the `currentVersion` command and return the passed in version string.
+  ///
+  /// This is useful for testing purposes.
+  ///
+  /// - Parameters:
+  ///   - version: The version string to return when `currentVersion` is called.
+  public mutating func override(with version: String) {
+    self.currentVersion = { _ in version }
+  }
+}
+
+extension GitVersionClient: TestDependencyKey {
+
+  /// The ``GitVersionClient`` used in test / debug builds.
+  public static let testValue = GitVersionClient(
+    currentVersion: unimplemented("\(Self.self).currentVersion", placeholder: "")
+  )
+
+  /// The ``GitVersionClient`` used in release builds.
+  public static var liveValue: GitVersionClient {
+    .init(currentVersion: { gitDirectory in
+      try GitVersion(workingDirectory: gitDirectory).currentVersion()
+    })
+  }
+}
+
+extension DependencyValues {
+
+  /// A ``GitVersionClient`` that can retrieve the current version from a
+  /// git directory.
+  public var gitVersionClient: GitVersionClient {
+    get { self[GitVersionClient.self] }
+    set { self[GitVersionClient.self] = newValue }
+  }
+}
+
+extension ShellCommand {
+  public static func gitCurrentSha(gitDirectory: String? = nil) -> Self {
+    GitVersion(workingDirectory: gitDirectory).command(for: .commit)
+  }
+
+  public static func gitCurrentBranch(gitDirectory: String? = nil) -> Self {
+    GitVersion(workingDirectory: gitDirectory).command(for: .branch)
+  }
+
+  public static func gitCurrentTag(gitDirectory: String? = nil) -> Self {
+    GitVersion(workingDirectory: gitDirectory).command(for: .describe)
+  }
+}
+
+// MARK: - Private
+fileprivate struct GitVersion {
+  @Dependency(\.logger) var logger: Logger
+  @Dependency(\.shellClient) var shell: ShellClient
+
+  let workingDirectory: String?
+
+  func currentVersion() throws -> String {
+    logger.debug("\("Fetching current version".bold)")
+    do {
+      logger.debug("Checking for tag.")
+      return try run(command: command(for: .describe))
+    } catch {
+      logger.debug("\("No tag found, deferring to branch & git sha".red)")
+      let branch = try run(command: command(for: .branch))
+      let commit = try run(command: command(for: .commit))
+      return "\(branch) \(commit)"
+    }
+  }
+
+  internal func command(for argument: VersionArgs) -> ShellCommand {
+    .init(
+      shell: .env,
+      environment: nil,
+      in: workingDirectory ?? FileManager.default.currentDirectoryPath,
+      argument.arguments
+    )
+  }
+}
+
+fileprivate extension GitVersion {
+  func run(command: ShellCommand) throws -> String {
+    try shell.background(command, trimmingCharactersIn: .whitespacesAndNewlines)
+  }
+
+  enum VersionArgs {
+    case branch
+    case commit
+    case describe
+
+    var arguments: [Args] {
+      switch self {
+      case .branch:
+        return [.git, .symbolicRef, .quiet, .short, .head]
+      case .commit:
+        return [.git, .revParse, .short, .head]
+      case .describe:
+        return [.git, .describe, .tags, .exactMatch]
+      }
+    }
+
+    enum Args: String, CustomStringConvertible {
+      case git
+      case describe
+      case tags = "--tags"
+      case exactMatch = "--exact-match"
+      case quiet = "--quiet"
+      case symbolicRef = "symbolic-ref"
+      case revParse = "rev-parse"
+      case short = "--short"
+      case head = "HEAD"
+    }
+
+  }
+}
+
+extension RawRepresentable where RawValue == String, Self: CustomStringConvertible {
+  var description: String { rawValue }
+}