Initial commit

Sources/GitVersion/LiveKey.swift

@@ -0,0 +1,80 @@
+import Foundation
+import ShellClient
+
+extension GitVersionClient: DependencyKey {
+  
+  public static var liveValue: GitVersionClient {
+    .init(currentVersion: { gitDirectory in
+      try GitVersion(workingDirectory: gitDirectory).currentVersion()
+    })
+  }
+}
+
+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)"
+    }
+  }
+  
+  private func command(for argument: VersionArgs) -> ShellCommand {
+    .init(
+      shell: .env,
+      environment: nil,
+      in: workingDirectory,
+      arguments: 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"
+    }
+    
+  }
+}
+
+fileprivate extension RawRepresentable where RawValue == String, Self: CustomStringConvertible {
+  var description: String { rawValue }
+}