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FBControlCore

The base framework of the idb project: FBSimulatorControl, FBDeviceControl and XCTestBootstrap are all built on it. It defines the interfaces that make an iOS Simulator and an iOS Device interchangeable to callers, and provides the machinery those frameworks share.

Like the rest of the project, it is a mix of Objective-C and Swift, transitioning to pure Swift, and is usable from both languages.

What it provides​

  • Targets. FBiOSTarget describes a single iOS Simulator or Device; FBSimulator and FBDevice implement it in their respective frameworks, so higher layers can treat a target uniformly regardless of its kind. FBiOSTargetSet is the counterpart for collections of targets.
  • Command protocols. Functionality is defined as protocols, such as ApplicationCommands, implemented separately for Simulators and Devices. Protocols common to both are part of FBiOSTarget; target-specific ones are declared on the concrete classes. Older protocols are Objective-C and return an FBFuture; newer ones are Swift with async methods.
  • Configuration values. Value types such as FBApplicationLaunchConfiguration gather the arguments to a call, providing defaults instead of long parameter lists.
  • Asynchrony. The Objective-C core encapsulates asynchronous work in FBFuture; Swift code uses Swift Concurrency, with bridging between the two.
  • IO and processes. Abstractions for reading and writing between sources and sinks (FBFileReader, FBFileWriter), and for spawning and supervising processes, backed by libdispatch.
  • Logging. FBControlCoreLogger provides a common logging interface for all of the frameworks.

The architecture documentation covers how these pieces fit together in idb.