Raised when a bad requirement is encountered
The RequirementList is used to hold the requirements being considered while resolving a set of gems.
The RequirementList acts like a queue where the oldest items are removed first.
This is not an existing class, but documentation of the interface that Scheduler object should comply to in order to be used as argument to Fiber.scheduler and handle non-blocking fibers. See also the “Non-blocking fibers” section in Fiber class docs for explanations of some concepts.
Scheduler’s behavior and usage are expected to be as follows:
When the execution in the non-blocking Fiber reaches some blocking operation (like sleep, wait for a process, or a non-ready I/O), it calls some of the scheduler’s hook methods, listed below.
Scheduler somehow registers what the current fiber is waiting on, and yields control to other fibers with Fiber.yield (so the fiber would be suspended while expecting its wait to end, and other fibers in the same thread can perform)
At the end of the current thread execution, the scheduler’s method close is called
The scheduler runs into a wait loop, checking all the blocked fibers (which it has registered on hook calls) and resuming them when the awaited resource is ready (e.g. I/O ready or sleep time elapsed).
A typical implementation would probably rely for this closing loop on a gem like EventMachine or Async.
This way concurrent execution will be achieved transparently for every individual Fiber’s code.
Hook methods are:
(the list is expanded as Ruby developers make more methods having non-blocking calls)
When not specified otherwise, the hook implementations are mandatory: if they are not implemented, the methods trying to call hook will fail. To provide backward compatibility, in the future hooks will be optional (if they are not implemented, due to the scheduler being created for the older Ruby version, the code which needs this hook will not fail, and will just behave in a blocking fashion).
It is also strongly recommended that the scheduler implements the fiber method, which is delegated to by Fiber.schedule.
Sample toy implementation of the scheduler can be found in Ruby’s code, in test/fiber/scheduler.rb
Enumerator::Chain is a subclass of Enumerator, which represents a chain of enumerables that works as a single enumerator.
This type of objects can be created by Enumerable#chain and Enumerator#+.
Thrown when PTY::check is called for a pid that represents a process that has exited.
spell checker for a dictionary that has a tree structure, see doc/tree_spell_checker_api.md
Error raised by a dRuby protocol when it doesn’t support the scheme specified in a URI. See DRb::DRbProtocol.
Individual switch class. Not important to the user.
Defined within Switch are several Switch-derived classes: NoArgument, RequiredArgument, etc.
Generated when trying to lookup a gem to indicate that the gem was found, but that it isn’t usable on the current platform.
fetch and install read these and report them to the user to aid in figuring out why a gem couldn’t be installed.
An error that indicates we weren’t able to fetch some data from a source
Raised when a gem dependencies file specifies a ruby version that does not match the current version.
RemoteFetcher handles the details of fetching gems and gem information from a remote source.
SpecFetcher handles metadata updates from remote gem repositories.