[commit: packages/Cabal] ghc-head: Add a list command to the HcPkg module (5fb7415)

[git at git.haskell.org]

Repository : ssh://git@git.haskell.org/Cabal

On branch  : ghc-head
Link       : http://git.haskell.org/?p=packages/Cabal.git;a=commit;h=5fb7415d362968dfb9d962b2d8a04640c9f6dd93

>---------------------------------------------------------------

commit 5fb7415d362968dfb9d962b2d8a04640c9f6dd93
Author: Duncan Coutts <duncan at community.haskell.org>
Date:   Wed Jul 24 23:52:08 2013 +0100

    Add a list command to the HcPkg module
    
    Only useful for getting the source package ids. Does not get the
    installed package ids or any other details. Most use cases should
    still use dump.


>---------------------------------------------------------------

5fb7415d362968dfb9d962b2d8a04640c9f6dd93
 Cabal/Distribution/Simple/Program/HcPkg.hs |   48 ++++++++++++++++++++++++++--
 1 file changed, 45 insertions(+), 3 deletions(-)

diff --git a/Cabal/Distribution/Simple/Program/HcPkg.hs b/Cabal/Distribution/Simple/Program/HcPkg.hs
index 44846fc..213146a 100644
--- a/Cabal/Distribution/Simple/Program/HcPkg.hs
+++ b/Cabal/Distribution/Simple/Program/HcPkg.hs
@@ -1,7 +1,7 @@
 -----------------------------------------------------------------------------
 -- |
 -- Module      :  Distribution.Simple.Program.HcPkg
--- Copyright   :  Duncan Coutts 2009
+-- Copyright   :  Duncan Coutts 2009, 2013
 --
 -- Maintainer  :  cabal-devel at haskell.org
 -- Portability :  portable
@@ -18,6 +18,7 @@ module Distribution.Simple.Program.HcPkg (
     expose,
     hide,
     dump,
+    list,
 
     -- * Program invocations
     initInvocation,
@@ -27,6 +28,7 @@ module Distribution.Simple.Program.HcPkg (
     exposeInvocation,
     hideInvocation,
     dumpInvocation,
+    listInvocation,
   ) where
 
 import Prelude hiding (init)
@@ -47,7 +49,7 @@ import Distribution.Simple.Program.Run
 import Distribution.Version
          ( Version(..) )
 import Distribution.Text
-         ( display )
+         ( display, simpleParse )
 import Distribution.Simple.Utils
          ( die )
 import Distribution.Verbosity
@@ -140,7 +142,8 @@ hide verbosity hcPkg packagedb pkgid =
     (hideInvocation hcPkg verbosity packagedb pkgid)
 
 
--- | Call @hc-pkg@ to get all the installed packages.
+-- | Call @hc-pkg@ to get all the details of all the packages in the given
+-- package database.
 --
 dump :: Verbosity -> ConfiguredProgram -> PackageDB -> IO [InstalledPackageInfo]
 dump verbosity hcPkg packagedb = do
@@ -246,6 +249,33 @@ setInstalledPackageId pkginfo at InstalledPackageInfo {
 setInstalledPackageId pkginfo = pkginfo
 
 
+-- | Call @hc-pkg@ to get the source package Id of all the packages in the
+-- given package database.
+--
+-- This is much less information than with 'dump', but also rather quicker.
+-- Note in particular that it does not include the 'InstalledPackageId', just
+-- the source 'PackageId' which is not necessarily unique in any package db.
+--
+list :: Verbosity -> ConfiguredProgram -> PackageDB -> IO [PackageId]
+list verbosity hcPkg packagedb = do
+
+  output <- getProgramInvocationOutput verbosity
+              (listInvocation hcPkg verbosity packagedb)
+    `catchExit` \_ -> die $ programId hcPkg ++ " list failed"
+
+  case parsePackageIds output of
+    Just ok -> return ok
+    _       -> die $ "failed to parse output of '"
+                  ++ programId hcPkg ++ " list'"
+
+  where
+    parsePackageIds str =
+      let parsed = map simpleParse (words str)
+       in case [ () | Nothing <- parsed ] of
+            [] -> Just [ pkgid | Just pkgid <- parsed ]
+            _  -> Nothing
+
+
 --------------------------
 -- The program invocations
 --
@@ -329,6 +359,18 @@ dumpInvocation hcPkg _verbosity packagedb =
            -- We use verbosity level 'silent' because it is important that we
            -- do not contaminate the output with info/debug messages.
 
+listInvocation :: ConfiguredProgram
+               -> Verbosity -> PackageDB -> ProgramInvocation
+listInvocation hcPkg _verbosity packagedb =
+    (programInvocation hcPkg args) {
+      progInvokeOutputEncoding = IOEncodingUTF8
+    }
+  where
+    args = ["list", "--simple-output", packageDbOpts hcPkg packagedb]
+        ++ verbosityOpts hcPkg silent
+           -- We use verbosity level 'silent' because it is important that we
+           -- do not contaminate the output with info/debug messages.
+
 
 packageDbStackOpts :: ConfiguredProgram -> PackageDBStack -> [String]
 packageDbStackOpts hcPkg dbstack = case dbstack of