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Merge branch 'jn/fast-import-doc'

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By Jonathan Nieder
* jn/fast-import-doc:
  fast-import doc: cat-blob and ls responses need to be consumed quickly
This commit is contained in:
Junio C Hamano
2012-04-23 13:01:32 -07:00
parent eb9756bd35 d57e490af3
commit b5d681ba81
1 changed files with 39 additions and 3 deletions
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42
Documentation/git-fast-import.txt
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@ -98,9 +98,10 @@ OPTIONS
options. options.
--cat-blob-fd=<fd>:: --cat-blob-fd=<fd>::
Specify the file descriptor that will be written to Write responses to `cat-blob` and `ls` queries to the
when the `cat-blob` command is encountered in the stream. file descriptor <fd> instead of `stdout`. Allows `progress`
The default behaviour is to write to `stdout`. output intended for the end-user to be separated from other
output.
--done:: --done::
Require a `done` command at the end of the stream. Require a `done` command at the end of the stream.
@ -942,6 +943,9 @@ This command can be used anywhere in the stream that comments are
accepted. In particular, the `cat-blob` command can be used in the 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. middle of a commit but not in the middle of a `data` command.
See ``Responses To Commands'' below for details about how to read
this output safely.
`ls` `ls`
~~~~ ~~~~
Prints information about the object at a path to a file descriptor Prints information about the object at a path to a file descriptor
@ -991,6 +995,9 @@ instead report
missing SP <path> LF missing SP <path> LF
==== ====
See ``Responses To Commands'' below for details about how to read
this output safely.
`feature` `feature`
~~~~~~~~~ ~~~~~~~~~
Require that fast-import supports the specified feature, or abort if Require that fast-import supports the specified feature, or abort if
@ -1079,6 +1086,35 @@ If the `--done` command line option or `feature done` command is
in use, the `done` command is mandatory and marks the end of the in use, the `done` command is mandatory and marks the end of the
stream. stream.
Responses To Commands
---------------------
New objects written by fast-import are not available immediately.
Most fast-import commands have no visible effect until the next
checkpoint (or completion). The frontend can send commands to
fill fast-import's input pipe without worrying about how quickly
they will take effect, which improves performance by simplifying
scheduling.
For some frontends, though, it is useful to be able to read back
data from the current repository as it is being updated (for
example when the source material describes objects in terms of
patches to be applied to previously imported objects). This can
be accomplished by connecting the frontend and fast-import via
bidirectional pipes:
====
mkfifo fast-import-output
frontend <fast-import-output |
git fast-import >fast-import-output
====
A frontend set up this way can use `progress`, `ls`, and `cat-blob`
commands to read information from the import in progress.
To avoid deadlock, such frontends must completely consume any
pending output from `progress`, `ls`, and `cat-blob` before
performing writes to fast-import that might block.
Crash Reports Crash Reports
------------- -------------
If fast-import is supplied invalid input it will terminate with a If fast-import is supplied invalid input it will terminate with a