get: Add --batch and --json options.

CHANGELOG

@@ -3,6 +3,7 @@ git-annex (6.20160614) UNRELEASED; urgency=medium
   * Webapp: Don't allow deleting a remote that has syncing disabled,
     as such a deletion will never finish.
     Thanks, Farhan Kathawala.
+  * get: Add --batch and --json options.
 
  -- Joey Hess <id@joeyh.name>  Mon, 13 Jun 2016 21:52:24 -0400
 

Command/Get.hs

@@ -16,7 +16,7 @@ import Annex.Wanted
 import qualified Command.Move
 
 cmd :: Command
-cmd = withGlobalOptions (jobsOption : annexedMatchingOptions) $ 
+cmd = withGlobalOptions (jobsOption : jsonOption : annexedMatchingOptions) $ 
 	command "get" SectionCommon 
 		"make content of annexed files available"
 		paramPaths (seek <$$> optParser)
@@ -26,6 +26,7 @@ data GetOptions = GetOptions
 	, getFrom :: Maybe (DeferredParse Remote)
 	, autoMode :: Bool
 	, keyOptions :: Maybe KeyOptions
+	, batchOption :: BatchMode
 	}
 
 optParser :: CmdParamsDesc -> Parser GetOptions
@@ -34,14 +35,18 @@ optParser desc = GetOptions
 	<*> optional parseFromOption
 	<*> parseAutoOption
 	<*> optional (parseKeyOptions True)
+	<*> parseBatchOption
 
 seek :: GetOptions -> CommandSeek
 seek o = allowConcurrentOutput $ do
 	from <- maybe (pure Nothing) (Just <$$> getParsed) (getFrom o)
-	withKeyOptions (keyOptions o) (autoMode o)
-		(startKeys from)
-		(withFilesInGit $ whenAnnexed $ start o from)
-		(getFiles o)
+	let go = whenAnnexed $ start o from
+	case batchOption o of
+		Batch -> batchInput Right (batchCommandAction . go)
+		NoBatch -> withKeyOptions (keyOptions o) (autoMode o)
+			(startKeys from)
+			(withFilesInGit go)
+			(getFiles o)
 
 start :: GetOptions -> Maybe Remote -> FilePath -> Key -> CommandStart
 start o from file key = start' expensivecheck from key (Just file)

doc/git-annex-get.mdwn

@@ -45,6 +45,11 @@ or transferring them from some kind of key-value store.
   as git-annex does not know the associated file, and the associated file
   may not even be in the current git working directory.
 
+* file matching options
+ 
+  The [[git-annex-matching-options]](1)
+  can be used to specify files to get.
+
 * `--all`
 
   Rather than specifying a filename or path to get, this option can be
@@ -60,10 +65,23 @@ or transferring them from some kind of key-value store.
 
   Use this option to get a specified key.
 
-* file matching options
- 
-  The [[git-annex-matching-options]](1)
-  can be used to specify files to get.
+* `--batch`
+
+  Enables batch mode, in which lines containing names of files to get
+  are read from stdin.
+
+  As each specified file is processed, the usual progress output is
+  displayed. If the specified file's content is already present, or
+  it is not an annexed file, a blank line is output in response instead.
+
+  Since the usual progress output while getting a file is verbose and not
+  machine-parseable, you may want to use --json in combination with
+  --batch.
+
+* `--json`
+
+  Enable JSON output. This is intended to be parsed by programs that use
+  git-annex. Each line of output is a JSON object.
 
 # SEE ALSO
 

doc/todo/get_--batch.mdwn

@@ -1,3 +1,7 @@
 It seems that it would be tremendously useful, see e.g. our [datalad install](https://github.com/datalad/datalad/issues/553)
 
-[[!meta author =yoh]]
+[[!meta author=yoh]]
+
+> [[done]] although the output while getting a file is not
+> machine-parseable. So, I made --json also work for get, but enabling
+> json output disables any progress display. --[[Joey]]