Merge branch 'jn/fast-import-blob-access'

* jn/fast-import-blob-access:
  t9300: avoid short reads from dd
  t9300: remove unnecessary use of /dev/stdin
  fast-import: Allow cat-blob requests at arbitrary points in stream
  fast-import: let importers retrieve blobs
  fast-import: clarify documentation of "feature" command
  fast-import: stricter parsing of integer options

Conflicts:
	fast-import.c

1 files changed, 62 insertions, 20 deletions

diff --git a/Documentation/git-fast-import.txt b/Documentation/git-fast-import.txt
index 9667e9aebc..f56dfcabb9 100644
--- a/Documentation/git-fast-import.txt
+++ b/Documentation/git-fast-import.txt
@@ -92,6 +92,11 @@ OPTIONS
 	--(no-)-relative-marks= with the --(import|export)-marks=
 	options.
 
+--cat-blob-fd=<fd>::
+	Specify the file descriptor that will be written to
+	when the `cat-blob` command is encountered in the stream.
+	The default behaviour is to write to `stdout`.
+
 --export-pack-edges=<file>::
 	After creating a packfile, print a line of data to
 	<file> listing the filename of the packfile and the last
@@ -320,6 +325,11 @@ and control the current import process.  More detailed discussion
 	standard output.  This command is optional and is not needed
 	to perform an import.
 
+`cat-blob`::
+	Causes fast-import to print a blob in 'cat-file --batch'
+	format to the file descriptor set with `--cat-blob-fd` or
+	`stdout` if unspecified.
+
 `feature`::
 	Require that fast-import supports the specified feature, or
 	abort if it does not.
@@ -879,34 +889,65 @@ Placing a `progress` command immediately after a `checkpoint` will
 inform the reader when the `checkpoint` has been completed and it
 can safely access the refs that fast-import updated.
 
-`feature`
-~~~~~~~~~
-Require that fast-import supports the specified feature, or abort if
-it does not.
+`cat-blob`
+~~~~~~~~~~
+Causes fast-import to print a blob to a file descriptor previously
+arranged with the `--cat-blob-fd` argument.  The command otherwise
+has no impact on the current import; its main purpose is to
+retrieve blobs that may be in fast-import's memory but not
+accessible from the target repository.
 
 ....
-	'feature' SP <feature> LF
+	'cat-blob' SP <dataref> LF
 ....
 
-The <feature> part of the command may be any string matching
-^[a-zA-Z][a-zA-Z-]*$ and should be understood by fast-import.
+The `<dataref>` can be either a mark reference (`:<idnum>`)
+set previously or a full 40-byte SHA-1 of a Git blob, preexisting or
+ready to be written.
 
-Feature work identical as their option counterparts with the
-exception of the import-marks feature, see below.
+output uses the same format as `git cat-file --batch`:
 
-The following features are currently supported:
+====
+	<sha1> SP 'blob' SP <size> LF
+	<contents> LF
+====
 
-* date-format
-* import-marks
-* export-marks
-* relative-marks
-* no-relative-marks
-* force
+This command can be used anywhere in the stream that comments are
+accepted.  In particular, the `cat-blob` command can be used in the
+middle of a commit but not in the middle of a `data` command.
+
+`feature`
+~~~~~~~~~
+Require that fast-import supports the specified feature, or abort if
+it does not.
+
+....
+	'feature' SP <feature> ('=' <argument>)? LF
+....
 
-The import-marks behaves differently from when it is specified as
-commandline option in that only one "feature import-marks" is allowed
-per stream. Also, any --import-marks= specified on the commandline
-will override those from the stream (if any).
+The <feature> part of the command may be any one of the following:
+
+date-format::
+export-marks::
+relative-marks::
+no-relative-marks::
+force::
+	Act as though the corresponding command-line option with
+	a leading '--' was passed on the command line
+	(see OPTIONS, above).
+
+import-marks::
+	Like --import-marks except in two respects: first, only one
+	"feature import-marks" command is allowed per stream;
+	second, an --import-marks= command-line option overrides
+	any "feature import-marks" command in the stream.
+
+cat-blob::
+	Ignored.  Versions of fast-import not supporting the
+	"cat-blob" command will exit with a message indicating so.
+	This lets the import error out early with a clear message,
+	rather than wasting time on the early part of an import
+	before the unsupported command is detected.
 
 `option`
 ~~~~~~~~
@@ -933,6 +974,7 @@ not be passed as option:
 * date-format
 * import-marks
 * export-marks
+* cat-blob-fd
 * force
 
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