split off background jobs into shelly-extra

* one less dependency (SafeSemaphore) for shelly

Shelly.hs

@@ -55,9 +55,6 @@ module Shelly
          , mv, rm, rm_f, rm_rf, cp, cp_r, mkdir, mkdir_p
          , readfile, writefile, appendfile, withTmpDir
 
-         -- * Running external commands asynchronously.
-         , jobs, background, getBgResult, BgResult
-
          -- * exiting the program
          , exit, errorExit, terror
 
@@ -72,6 +69,9 @@ module Shelly
 
          -- * Re-exported for your convenience
          , liftIO, when, unless, FilePath
+
+         -- * internal functions for writing extension
+         , get, put
          ) where
 
 -- TODO:
@@ -109,7 +109,6 @@ import Control.Applicative
 import Control.Exception hiding (handle)
 import Control.Monad.Reader
 import Control.Concurrent
-import qualified Control.Concurrent.MSem as Sem
 import Data.Time.Clock( getCurrentTime, diffUTCTime  )
 
 import qualified Data.Text.Lazy.IO as TIO
@@ -694,53 +693,6 @@ verbosely a = sub $ modify (\x -> x { sPrintStdout = True, sPrintCommands = True
 print_stdout :: Bool -> ShIO a -> ShIO a
 print_stdout shouldPrint a = sub $ modify (\x -> x { sPrintStdout = shouldPrint }) >> a
 
--- | Create a 'BgJobManager' that has a 'limit' on the max number of background tasks.
--- an invocation of jobs is independent of any others, and not tied to the ShIO monad in any way.
--- This blocks the execution of the program until all 'background' jobs are finished.
-jobs :: Int -> (BgJobManager -> ShIO a) -> ShIO a
-jobs limit action = do
-    unless (limit > 0) $ terror "expected limit to be > 0"
-    availableJobsSem <- liftIO $ Sem.new limit
-    res <- action $ BgJobManager availableJobsSem
-    liftIO $ waitForJobs availableJobsSem
-    return res
-  where
-    waitForJobs sem = do
-      avail <- Sem.peekAvail sem
-      if avail == limit then return () else waitForJobs sem
-
--- | The manager tracks the number of jobs. Register your 'background' jobs with it.
-newtype BgJobManager = BgJobManager (Sem.MSem Int)
-
--- | Type returned by tasks run asynchronously in the background.
-newtype BgResult a = BgResult (MVar a)
-
--- | Returns the promised result from a backgrounded task.  Blocks until
--- the task completes.
-getBgResult :: BgResult a -> ShIO a
-getBgResult (BgResult mvar) = liftIO $ takeMVar mvar
-
--- | Run the `ShIO` task asynchronously in the background, returns
--- the `BgResult a`, a promise immediately. Run "getBgResult" to wait for the result.
--- The background task will inherit the current ShIO context
--- The 'BjJobManager' ensures the max jobs limit must be sufficient for the parent and all children.
-background :: BgJobManager -> ShIO a -> ShIO (BgResult a)
-background (BgJobManager manager) proc = do
-  state <- get
-  liftIO $ do
-    -- take up a spot
-    -- It is important to do this before forkIO:
-    -- It ensures that that jobs will block and the program won't exit before our jobs are done
-    -- On the other hand, a user might not expect 'jobs' to block
-    Sem.wait manager
-    mvar <- newEmptyMVar -- future result
-
-    _<- forkIO $ do
-      result <- shelly $ (put state >> proc)
-      Sem.signal manager -- open a spot back up
-      liftIO $ putMVar mvar result
-    return $ BgResult mvar
-
 
 -- | Turn on/off command echoing.
 print_commands :: Bool -> ShIO a -> ShIO a

shelly-extra/LICENSE

@@ -0,0 +1,30 @@
+Copyright (c) 2010, Petr Rockai <[email protected]>
+
+All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are met:
+
+    * Redistributions of source code must retain the above copyright
+      notice, this list of conditions and the following disclaimer.
+
+    * Redistributions in binary form must reproduce the above
+      copyright notice, this list of conditions and the following
+      disclaimer in the documentation and/or other materials provided
+      with the distribution.
+
+    * Neither the name of Petr Rockai nor the names of other
+      contributors may be used to endorse or promote products derived
+      from this software without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

shelly-extra/Shelly/Extra.hs

@@ -0,0 +1,57 @@
+{-# LANGUAGE OverloadedStrings #-}
+module Shelly.Extra (
+   -- * Running external commands asynchronously.
+   jobs, background, getBgResult, BgResult
+) where
+
+import Shelly
+import Control.Concurrent
+import qualified Control.Concurrent.MSem as Sem
+
+-- | Create a 'BgJobManager' that has a 'limit' on the max number of background tasks.
+-- an invocation of jobs is independent of any others, and not tied to the ShIO monad in any way.
+-- This blocks the execution of the program until all 'background' jobs are finished.
+jobs :: Int -> (BgJobManager -> ShIO a) -> ShIO a
+jobs limit action = do
+    unless (limit > 0) $ terror "expected limit to be > 0"
+    availableJobsSem <- liftIO $ Sem.new limit
+    res <- action $ BgJobManager availableJobsSem
+    liftIO $ waitForJobs availableJobsSem
+    return res
+  where
+    waitForJobs sem = do
+      avail <- Sem.peekAvail sem
+      if avail == limit then return () else waitForJobs sem
+
+-- | The manager tracks the number of jobs. Register your 'background' jobs with it.
+newtype BgJobManager = BgJobManager (Sem.MSem Int)
+
+-- | Type returned by tasks run asynchronously in the background.
+newtype BgResult a = BgResult (MVar a)
+
+-- | Returns the promised result from a backgrounded task.  Blocks until
+-- the task completes.
+getBgResult :: BgResult a -> ShIO a
+getBgResult (BgResult mvar) = liftIO $ takeMVar mvar
+
+-- | Run the `ShIO` task asynchronously in the background, returns
+-- the `BgResult a`, a promise immediately. Run "getBgResult" to wait for the result.
+-- The background task will inherit the current ShIO context
+-- The 'BjJobManager' ensures the max jobs limit must be sufficient for the parent and all children.
+background :: BgJobManager -> ShIO a -> ShIO (BgResult a)
+background (BgJobManager manager) proc = do
+  state <- get
+  liftIO $ do
+    -- take up a spot
+    -- It is important to do this before forkIO:
+    -- It ensures that that jobs will block and the program won't exit before our jobs are done
+    -- On the other hand, a user might not expect 'jobs' to block
+    Sem.wait manager
+    mvar <- newEmptyMVar -- future result
+
+    _<- forkIO $ do
+      result <- shelly $ (put state >> proc)
+      Sem.signal manager -- open a spot back up
+      liftIO $ putMVar mvar result
+    return $ BgResult mvar
+

shelly-extra/shelly-extra.cabal

@@ -0,0 +1,44 @@
+Name:       shelly
+
+Version:     0.9.8
+Synopsis:    shelly features that require extra dependencies
+
+Description: Please see the shelly package. Shelly provides a single module for convenient
+             systems programming in Haskell, similar in spirit to POSIX shells.
+             .
+             shelly-extra is designed to be a grab bag for functionality that requires extra dependencies
+             .
+             currently contains a background job implementation for performing tasks in parallel
+
+
+Homepage:            https://github.com/yesodweb/Shelly.hs
+License:             BSD3
+License-file:        LICENSE
+Author:              Greg Weber
+Maintainer:          Greg Weber <[email protected]>
+Category:            Development
+Build-type:          Simple
+Cabal-version:       >=1.8
+
+
+Library
+  Exposed-modules:     Shelly.Extra
+
+  Build-depends: base, shelly >= 0.10 , SafeSemaphore
+
+  ghc-options: -Wall
+
+test-suite test
+    type:           exitcode-stdio-1.0
+    main-is:        main.hs
+    hs-source-dirs: ., test
+    ghc-options: -Wall
+
+    Build-depends: base 
+                 , hspec-discover
+                 , hspec >= 1.1
+                 , HUnit
+
+source-repository head
+  type:     git
+  location: https://github.com/yesodweb/Shelly.hs

shelly.cabal

@@ -1,6 +1,6 @@
 Name:       shelly
 
-Version:     0.9.8
+Version:     0.10
 Synopsis:    shell-like (systems) programming in Haskell
 
 Description: Shelly provides a single module for convenient
@@ -34,7 +34,6 @@ Library
 
   Build-depends: base >= 4 && < 5, time, directory, text, mtl
                , process >= 1.0
-               , SafeSemaphore
                , unix-compat < 0.4
                , system-filepath < 0.5
                , system-fileio < 0.4
@@ -48,7 +47,6 @@ test-suite test
     ghc-options: -Wall
 
     Build-depends: base >= 4 && < 5, time, directory, text, mtl, process
-                 , SafeSemaphore
                  , unix-compat < 0.4
                  , system-filepath < 0.5
                  , system-fileio < 0.4