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-rw-r--r--Documentation/git-remote-helpers.txt234
1 files changed, 144 insertions, 90 deletions
diff --git a/Documentation/git-remote-helpers.txt b/Documentation/git-remote-helpers.txt
index f5836e46d0..6d696e0f90 100644
--- a/Documentation/git-remote-helpers.txt
+++ b/Documentation/git-remote-helpers.txt
@@ -35,6 +35,37 @@ transport protocols, such as 'git-remote-http', 'git-remote-https',
'git-remote-ftp' and 'git-remote-ftps'. They implement the capabilities
'fetch', 'option', and 'push'.
+INVOCATION
+----------
+
+Remote helper programs are invoked with one or (optionally) two
+arguments. The first argument specifies a remote repository as in git;
+it is either the name of a configured remote or a URL. The second
+argument specifies a URL; it is usually of the form
+'<transport>://<address>', but any arbitrary string is possible.
+The 'GIT_DIR' environment variable is set up for the remote helper
+and can be used to determine where to store additional data or from
+which directory to invoke auxiliary git commands.
+
+When git encounters a URL of the form '<transport>://<address>', where
+'<transport>' is a protocol that it cannot handle natively, it
+automatically invokes 'git remote-<transport>' with the full URL as
+the second argument. If such a URL is encountered directly on the
+command line, the first argument is the same as the second, and if it
+is encountered in a configured remote, the first argument is the name
+of that remote.
+
+A URL of the form '<transport>::<address>' explicitly instructs git to
+invoke 'git remote-<transport>' with '<address>' as the second
+argument. If such a URL is encountered directly on the command line,
+the first argument is '<address>', and if it is encountered in a
+configured remote, the first argument is the name of that remote.
+
+Additionally, when a configured remote has 'remote.<name>.vcs' set to
+'<transport>', git explicitly invokes 'git remote-<transport>' with
+'<name>' as the first argument. If set, the second argument is
+'remote.<name>.url'; otherwise, the second argument is omitted.
+
INPUT FORMAT
------------
@@ -57,53 +88,17 @@ Each remote helper is expected to support only a subset of commands.
The operations a helper supports are declared to git in the response
to the `capabilities` command (see COMMANDS, below).
-'option'::
- For specifying settings like `verbosity` (how much output to
- write to stderr) and `depth` (how much history is wanted in the
- case of a shallow clone) that affect how other commands are
- carried out.
-
-'connect'::
- For fetching and pushing using git's native packfile protocol
- that requires a bidirectional, full-duplex connection.
-
-'push'::
- For listing remote refs and pushing specified objects from the
- local object store to remote refs.
-
-'fetch'::
- For listing remote refs and fetching the associated history to
- the local object store.
-
-'import'::
- For listing remote refs and fetching the associated history as
- a fast-import stream.
-
-'refspec' <refspec>::
- This modifies the 'import' capability, allowing the produced
- fast-import stream to modify refs in a private namespace
- instead of writing to refs/heads or refs/remotes directly.
- It is recommended that all importers providing the 'import'
- capability use this.
-+
-A helper advertising the capability
-`refspec refs/heads/*:refs/svn/origin/branches/*`
-is saying that, when it is asked to `import refs/heads/topic`, the
-stream it outputs will update the `refs/svn/origin/branches/topic`
-ref.
-+
-This capability can be advertised multiple times. The first
-applicable refspec takes precedence. The left-hand of refspecs
-advertised with this capability must cover all refs reported by
-the list command. If no 'refspec' capability is advertised,
-there is an implied `refspec *:*`.
+In the following, we list all defined capabilities and for
+each we list which commands a helper with that capability
+must provide.
Capabilities for Pushing
-~~~~~~~~~~~~~~~~~~~~~~~~
+^^^^^^^^^^^^^^^^^^^^^^^^
'connect'::
Can attempt to connect to 'git receive-pack' (for pushing),
- 'git upload-pack', etc for communication using the
- packfile protocol.
+ 'git upload-pack', etc for communication using
+ git's native packfile protocol. This
+ requires a bidirectional, full-duplex connection.
+
Supported commands: 'connect'.
@@ -113,16 +108,26 @@ Supported commands: 'connect'.
+
Supported commands: 'list for-push', 'push'.
-If a helper advertises both 'connect' and 'push', git will use
-'connect' if possible and fall back to 'push' if the helper requests
-so when connecting (see the 'connect' command under COMMANDS).
+'export'::
+ Can discover remote refs and push specified objects from a
+ fast-import stream to remote refs.
++
+Supported commands: 'list for-push', 'export'.
+
+If a helper advertises 'connect', git will use it if possible and
+fall back to another capability if the helper requests so when
+connecting (see the 'connect' command under COMMANDS).
+When choosing between 'push' and 'export', git prefers 'push'.
+Other frontends may have some other order of preference.
+
Capabilities for Fetching
-~~~~~~~~~~~~~~~~~~~~~~~~~
+^^^^^^^^^^^^^^^^^^^^^^^^^
'connect'::
Can try to connect to 'git upload-pack' (for fetching),
'git receive-pack', etc for communication using the
- packfile protocol.
+ git's native packfile protocol. This
+ requires a bidirectional, full-duplex connection.
+
Supported commands: 'connect'.
@@ -144,14 +149,27 @@ connecting (see the 'connect' command under COMMANDS).
When choosing between 'fetch' and 'import', git prefers 'fetch'.
Other frontends may have some other order of preference.
+Miscellaneous capabilities
+^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+'option'::
+ For specifying settings like `verbosity` (how much output to
+ write to stderr) and `depth` (how much history is wanted in the
+ case of a shallow clone) that affect how other commands are
+ carried out.
+
'refspec' <refspec>::
- This modifies the 'import' capability.
+ This modifies the 'import' capability, allowing the produced
+ fast-import stream to modify refs in a private namespace
+ instead of writing to refs/heads or refs/remotes directly.
+ It is recommended that all importers providing the 'import'
+ capability use this.
+
-A helper advertising
+A helper advertising the capability
`refspec refs/heads/*:refs/svn/origin/branches/*`
-in its capabilities is saying that, when it handles
-`import refs/heads/topic`, the stream it outputs will update the
-`refs/svn/origin/branches/topic` ref.
+is saying that, when it is asked to `import refs/heads/topic`, the
+stream it outputs will update the `refs/svn/origin/branches/topic`
+ref.
+
This capability can be advertised multiple times. The first
applicable refspec takes precedence. The left-hand of refspecs
@@ -159,36 +177,33 @@ advertised with this capability must cover all refs reported by
the list command. If no 'refspec' capability is advertised,
there is an implied `refspec *:*`.
-INVOCATION
-----------
+'bidi-import'::
+ This modifies the 'import' capability.
+ The fast-import commands 'cat-blob' and 'ls' can be used by remote-helpers
+ to retrieve information about blobs and trees that already exist in
+ fast-import's memory. This requires a channel from fast-import to the
+ remote-helper.
+ If it is advertised in addition to "import", git establishes a pipe from
+ fast-import to the remote-helper's stdin.
+ It follows that git and fast-import are both connected to the
+ remote-helper's stdin. Because git can send multiple commands to
+ the remote-helper it is required that helpers that use 'bidi-import'
+ buffer all 'import' commands of a batch before sending data to fast-import.
+ This is to prevent mixing commands and fast-import responses on the
+ helper's stdin.
-Remote helper programs are invoked with one or (optionally) two
-arguments. The first argument specifies a remote repository as in git;
-it is either the name of a configured remote or a URL. The second
-argument specifies a URL; it is usually of the form
-'<transport>://<address>', but any arbitrary string is possible.
-The 'GIT_DIR' environment variable is set up for the remote helper
-and can be used to determine where to store additional data or from
-which directory to invoke auxiliary git commands.
+'export-marks' <file>::
+ This modifies the 'export' capability, instructing git to dump the
+ internal marks table to <file> when complete. For details,
+ read up on '--export-marks=<file>' in linkgit:git-fast-export[1].
+
+'import-marks' <file>::
+ This modifies the 'export' capability, instructing git to load the
+ marks specified in <file> before processing any input. For details,
+ read up on '--import-marks=<file>' in linkgit:git-fast-export[1].
-When git encounters a URL of the form '<transport>://<address>', where
-'<transport>' is a protocol that it cannot handle natively, it
-automatically invokes 'git remote-<transport>' with the full URL as
-the second argument. If such a URL is encountered directly on the
-command line, the first argument is the same as the second, and if it
-is encountered in a configured remote, the first argument is the name
-of that remote.
-A URL of the form '<transport>::<address>' explicitly instructs git to
-invoke 'git remote-<transport>' with '<address>' as the second
-argument. If such a URL is encountered directly on the command line,
-the first argument is '<address>', and if it is encountered in a
-configured remote, the first argument is the name of that remote.
-Additionally, when a configured remote has 'remote.<name>.vcs' set to
-'<transport>', git explicitly invokes 'git remote-<transport>' with
-'<name>' as the first argument. If set, the second argument is
-'remote.<name>.url'; otherwise, the second argument is omitted.
COMMANDS
--------
@@ -198,9 +213,11 @@ Commands are given by the caller on the helper's standard input, one per line.
'capabilities'::
Lists the capabilities of the helper, one per line, ending
with a blank line. Each capability may be preceded with '*',
- which marks them mandatory for git version using the remote
- helper to understand (unknown mandatory capability is fatal
- error).
+ which marks them mandatory for git versions using the remote
+ helper to understand. Any unknown mandatory capability is a
+ fatal error.
++
+Support for this command is mandatory.
'list'::
Lists the refs, one per line, in the format "<value> <name>
@@ -210,9 +227,20 @@ Commands are given by the caller on the helper's standard input, one per line.
the name; unrecognized attributes are ignored. The list ends
with a blank line.
+
-If 'push' is supported this may be called as 'list for-push'
-to obtain the current refs prior to sending one or more 'push'
-commands to the helper.
+See REF LIST ATTRIBUTES for a list of currently defined attributes.
++
+Supported if the helper has the "fetch" or "import" capability.
+
+'list for-push'::
+ Similar to 'list', except that it is used if and only if
+ the caller wants to the resulting ref list to prepare
+ push commands.
+ A helper supporting both push and fetch can use this
+ to distinguish for which operation the output of 'list'
+ is going to be used, possibly reducing the amount
+ of work that needs to be performed.
++
+Supported if the helper has the "push" or "export" capability.
'option' <name> <value>::
Sets the transport helper option <name> to <value>. Outputs a
@@ -222,6 +250,8 @@ commands to the helper.
for it). Options should be set before other commands,
and may influence the behavior of those commands.
+
+See OPTIONS for a list of currently defined options.
++
Supported if the helper has the "option" capability.
'fetch' <sha1> <name>::
@@ -230,7 +260,7 @@ Supported if the helper has the "option" capability.
per line, terminated with a blank line.
Outputs a single blank line when all fetch commands in the
same batch are complete. Only objects which were reported
- in the ref list with a sha1 may be fetched this way.
+ in the output of 'list' with a sha1 may be fetched this way.
+
Optionally may output a 'lock <file>' line indicating a file under
GIT_DIR/objects/pack which is keeping a pack until refs can be
@@ -286,8 +316,29 @@ terminated with a blank line. For each batch of 'import', the remote
helper should produce a fast-import stream terminated by a 'done'
command.
+
+Note that if the 'bidi-import' capability is used the complete batch
+sequence has to be buffered before starting to send data to fast-import
+to prevent mixing of commands and fast-import responses on the helper's
+stdin.
++
Supported if the helper has the "import" capability.
+'export'::
+ Instructs the remote helper that any subsequent input is
+ part of a fast-import stream (generated by 'git fast-export')
+ containing objects which should be pushed to the remote.
++
+Especially useful for interoperability with a foreign versioning
+system.
++
+The 'export-marks' and 'import-marks' capabilities, if specified,
+affect this command in so far as they are passed on to 'git
+fast-export', which then will load/store a table of marks for
+local objects. This can be used to implement for incremental
+operations.
++
+Supported if the helper has the "export" capability.
+
'connect' <service>::
Connects to given service. Standard input and standard output
of helper are connected to specified service (git prefix is
@@ -313,10 +364,9 @@ capabilities reported by the helper.
REF LIST ATTRIBUTES
-------------------
-'for-push'::
- The caller wants to use the ref list to prepare push
- commands. A helper might chose to acquire the ref list by
- opening a different type of connection to the destination.
+The 'list' command produces a list of refs in which each ref
+may be followed by a list of attributes. The following ref list
+attributes are defined.
'unchanged'::
This ref is unchanged since the last import or fetch, although
@@ -324,6 +374,10 @@ REF LIST ATTRIBUTES
OPTIONS
-------
+
+The following options are defined and (under suitable circumstances)
+set by git if the remote helper has the 'option' capability.
+
'option verbosity' <n>::
Changes the verbosity of messages displayed by the helper.
A value of 0 for <n> means that processes operate