git-annex/Types/Command.hs
Joey Hess 53882ab4a7
make WorkerStage an open type
Rather than limiting it to PerformStage and CleanupStage, this opens it
up so any number of stages can be added as needed by commands.

Each concurrent command has a set of stages that it uses, and only
transitions between those can block waiting for a free slot in the
worker pool. Calling enteringStage for some other stage does not block,
and has very little overhead.

Note that while before the Annex state was duplicated on the first call
to commandAction, this now happens earlier, in startConcurrency.
That means that seek stage actions should that use startConcurrency
and then modify Annex state won't modify the state of worker threads
they then start. I audited all of them, and only Command.Seek
did so; prepMerge changes the working directory and so has to come
before startConcurrency.

Also, the remote list is built before duplicating the state, which means
that it gets built earlier now than it used to. This would only have an
effect of making commands that end up not needing to perform any actions
unncessary build the remote list (only when they're run with concurrency
enable), but that's a minor overhead compared to commands seeking
through the work tree and determining they don't need to do anything.
2019-06-19 13:05:03 -04:00

123 lines
4.1 KiB
Haskell

{- git-annex command data types
-
- Copyright 2010-2019 Joey Hess <id@joeyh.name>
-
- Licensed under the GNU AGPL version 3 or higher.
-}
module Types.Command where
import Data.Ord
import Options.Applicative.Types (Parser)
import Types
import Types.DeferredParse
import Types.ActionItem
{- A command runs in these stages.
-
- a. The parser stage parses the command line and generates a CommandSeek
- action. -}
type CommandParser = Parser CommandSeek
{- b. The check stage runs checks, that error out if
- anything prevents the command from running. -}
data CommandCheck = CommandCheck { idCheck :: Int, runCheck :: Annex () }
{- c. The seek stage is passed input from the parser, looks through
- the repo to find things to act on (ie, new files to add), and
- runs commandAction to handle all necessary actions. -}
type CommandSeek = Annex ()
{- d. The start stage is run before anything is output, is passed some
- value from the seek stage, and can check if anything needs to be
- done, and early abort if not. It should run quickly and should
- not modify Annex state or output anything. -}
type CommandStart = Annex (Maybe (StartMessage, CommandPerform))
{- e. The perform stage is run after a message is printed about the command
- being run, and it should be where the bulk of the work happens. -}
type CommandPerform = Annex (Maybe CommandCleanup)
{- f. The cleanup stage is run only if the perform stage succeeds, and it
- returns the overall success/fail of the command. -}
type CommandCleanup = Annex Bool
{- Message that is displayed when starting to perform an action on
- something. The String is typically the name of the command or action
- being performed.
-}
data StartMessage
= StartMessage String ActionItem
| StartUsualMessages String ActionItem
-- ^ Like StartMessage, but makes sure to enable usual message
-- display in case it was disabled by cmdnomessages.
| StartNoMessage ActionItem
-- ^ Starts, without displaying any message but also without
-- disabling display of any of the usual messages.
| CustomOutput ActionItem
-- ^ Prevents any start, end, or other usual messages from
-- being displayed, letting a command output its own custom format.
deriving (Show)
instance MkActionItem StartMessage where
mkActionItem (StartMessage _ ai) = ai
mkActionItem (StartUsualMessages _ ai) = ai
mkActionItem (StartNoMessage ai) = ai
mkActionItem (CustomOutput ai) = ai
{- A command is defined by specifying these things. -}
data Command = Command
{ cmdcheck :: [CommandCheck]
-- ^ check stage
, cmdnocommit :: Bool
-- ^ don't commit journalled state changes
, cmdnomessages :: Bool
-- ^ don't output normal messages
, cmdname :: String
, cmdparamdesc :: CmdParamsDesc
-- ^ description of params for usage
, cmdsection :: CommandSection
, cmddesc :: String
-- ^ description of command for usage
, cmdparser :: CommandParser
-- ^ command line parser
, cmdglobaloptions :: [GlobalOption]
-- ^ additional global options
, cmdnorepo :: Maybe (Parser (IO ()))
-- ^used when not in a repo
}
{- Command-line parameters, after the command is selected and options
- are parsed. -}
type CmdParams = [String]
type CmdParamsDesc = String
{- CommandCheck functions can be compared using their unique id. -}
instance Eq CommandCheck where
a == b = idCheck a == idCheck b
instance Eq Command where
a == b = cmdname a == cmdname b
{- Order commands by name. -}
instance Ord Command where
compare = comparing cmdname
{- The same sections are listed in doc/git-annex.mdwn -}
data CommandSection
= SectionCommon
| SectionSetup
| SectionMaintenance
| SectionQuery
| SectionMetaData
| SectionUtility
| SectionPlumbing
| SectionTesting
deriving (Eq, Ord, Enum, Bounded)
descSection :: CommandSection -> String
descSection SectionCommon = "Commonly used commands"
descSection SectionSetup = "Repository setup commands"
descSection SectionMaintenance = "Repository maintenance commands"
descSection SectionQuery = "Query commands"
descSection SectionMetaData = "Metadata commands"
descSection SectionUtility = "Utility commands"
descSection SectionPlumbing = "Plumbing commands"
descSection SectionTesting = "Testing commands"