diff options
Diffstat (limited to 'Documentation/technical/pack-protocol.txt')
| -rw-r--r-- | Documentation/technical/pack-protocol.txt | 123 |
1 files changed, 89 insertions, 34 deletions
diff --git a/Documentation/technical/pack-protocol.txt b/Documentation/technical/pack-protocol.txt index 369f91d3b9..f1a51edf47 100644 --- a/Documentation/technical/pack-protocol.txt +++ b/Documentation/technical/pack-protocol.txt @@ -60,6 +60,13 @@ process on the server side over the Git protocol is this: "0039git-upload-pack /schacon/gitbook.git\0host=example.com\0" | nc -v example.com 9418 +If the server refuses the request for some reasons, it could abort +gracefully with an error message. + +---- + error-line = PKT-LINE("ERR" SP explanation-text) +---- + SSH Transport ------------- @@ -110,7 +117,7 @@ A few things to remember here: - The repository path is always quoted with single quotes. Fetching Data From a Server -=========================== +--------------------------- When one Git repository wants to get data that a second repository has, the first can 'fetch' from the second. This operation determines @@ -127,7 +134,8 @@ with the object name that each reference currently points to. $ echo -e -n "0039git-upload-pack /schacon/gitbook.git\0host=example.com\0" | nc -v example.com 9418 - 00887217a7c7e582c46cec22a130adf4b9d7d950fba0 HEAD\0multi_ack thin-pack side-band side-band-64k ofs-delta shallow no-progress include-tag + 00887217a7c7e582c46cec22a130adf4b9d7d950fba0 HEAD\0multi_ack thin-pack + side-band side-band-64k ofs-delta shallow no-progress include-tag 00441d3fcd5ced445d1abc402225c0b8a1299641f497 refs/heads/integration 003f7217a7c7e582c46cec22a130adf4b9d7d950fba0 refs/heads/master 003cb88d2441cac0977faf98efc80305012112238d9d refs/tags/v0.9 @@ -179,34 +187,36 @@ and descriptions. Packfile Negotiation -------------------- -After reference and capabilities discovery, the client can decide -to terminate the connection by sending a flush-pkt, telling the -server it can now gracefully terminate (as happens with the ls-remote -command) or it can enter the negotiation phase, where the client and -server determine what the minimal packfile necessary for transport is. - -Once the client has the initial list of references that the server -has, as well as the list of capabilities, it will begin telling the -server what objects it wants and what objects it has, so the server -can make a packfile that only contains the objects that the client needs. -The client will also send a list of the capabilities it wants to be in -effect, out of what the server said it could do with the first 'want' line. +After reference and capabilities discovery, the client can decide to +terminate the connection by sending a flush-pkt, telling the server it can +now gracefully terminate, and disconnect, when it does not need any pack +data. This can happen with the ls-remote command, and also can happen when +the client already is up-to-date. + +Otherwise, it enters the negotiation phase, where the client and +server determine what the minimal packfile necessary for transport is, +by telling the server what objects it wants, its shallow objects +(if any), and the maximum commit depth it wants (if any). The client +will also send a list of the capabilities it wants to be in effect, +out of what the server said it could do with the first 'want' line. ---- upload-request = want-list - have-list - compute-end + *shallow-line + *1depth-request + flush-pkt want-list = first-want *additional-want - flush-pkt + + shallow-line = PKT_LINE("shallow" SP obj-id) + + depth-request = PKT_LINE("deepen" SP depth) first-want = PKT-LINE("want" SP obj-id SP capability-list LF) additional-want = PKT-LINE("want" SP obj-id LF) - have-list = *have-line - have-line = PKT-LINE("have" SP obj-id LF) - compute-end = flush-pkt / PKT-LINE("done") + depth = 1*DIGIT ---- Clients MUST send all the obj-ids it wants from the reference @@ -215,21 +225,66 @@ discovery phase as 'want' lines. Clients MUST send at least one obj-id in a 'want' command which did not appear in the response obtained through ref discovery. -If client is requesting a shallow clone, it will now send a 'deepen' -line with the depth it is requesting. +The client MUST write all obj-ids which it only has shallow copies +of (meaning that it does not have the parents of a commit) as +'shallow' lines so that the server is aware of the limitations of +the client's history. Clients MUST NOT mention an obj-id which +it does not know exists on the server. + +The client now sends the maximum commit history depth it wants for +this transaction, which is the number of commits it wants from the +tip of the history, if any, as a 'deepen' line. A depth of 0 is the +same as not making a depth request. The client does not want to receive +any commits beyond this depth, nor objects needed only to complete +those commits. Commits whose parents are not received as a result are +defined as shallow and marked as such in the server. This information +is sent back to the client in the next step. + +Once all the 'want's and 'shallow's (and optional 'deepen') are +transferred, clients MUST send a flush-pkt, to tell the server side +that it is done sending the list. + +Otherwise, if the client sent a positive depth request, the server +will determine which commits will and will not be shallow and +send this information to the client. If the client did not request +a positive depth, this step is skipped. -Once all the "want"s (and optional 'deepen') are transferred, -clients MUST send a flush-pkt. If the client has all the references -on the server, client flushes and disconnects. +---- + shallow-update = *shallow-line + *unshallow-line + flush-pkt + + shallow-line = PKT-LINE("shallow" SP obj-id) + + unshallow-line = PKT-LINE("unshallow" SP obj-id) +---- -TODO: shallow/unshallow response and document the deepen command in the ABNF. +If the client has requested a positive depth, the server will compute +the set of commits which are no deeper than the desired depth. The set +of commits start at the client's wants. + +The server writes 'shallow' lines for each +commit whose parents will not be sent as a result. The server writes +an 'unshallow' line for each commit which the client has indicated is +shallow, but is no longer shallow at the currently requested depth +(that is, its parents will now be sent). The server MUST NOT mark +as unshallow anything which the client has not indicated was shallow. Now the client will send a list of the obj-ids it has using 'have' -lines. In multi_ack mode, the canonical implementation will send up -to 32 of these at a time, then will send a flush-pkt. The canonical -implementation will skip ahead and send the next 32 immediately, -so that there is always a block of 32 "in-flight on the wire" at a -time. +lines, so the server can make a packfile that only contains the objects +that the client needs. In multi_ack mode, the canonical implementation +will send up to 32 of these at a time, then will send a flush-pkt. The +canonical implementation will skip ahead and send the next 32 immediately, +so that there is always a block of 32 "in-flight on the wire" at a time. + +---- + upload-haves = have-list + compute-end + + have-list = *have-line + have-line = PKT-LINE("have" SP obj-id LF) + compute-end = flush-pkt / PKT-LINE("done") +---- If the server reads 'have' lines, it then will respond by ACKing any of the obj-ids the client said it had that the server also has. The @@ -299,7 +354,7 @@ Then the server will start sending its packfile data. A simple clone may look like this (with no 'have' lines): ---- - C: 0054want 74730d410fcb6603ace96f1dc55ea6196122532d\0multi_ack \ + C: 0054want 74730d410fcb6603ace96f1dc55ea6196122532d multi_ack \ side-band-64k ofs-delta\n C: 0032want 7d1665144a3a975c05f1f43902ddaf084e784dbe\n C: 0032want 5a3f6be755bbb7deae50065988cbfa1ffa9ab68a\n @@ -315,7 +370,7 @@ A simple clone may look like this (with no 'have' lines): An incremental update (fetch) response might look like this: ---- - C: 0054want 74730d410fcb6603ace96f1dc55ea6196122532d\0multi_ack \ + C: 0054want 74730d410fcb6603ace96f1dc55ea6196122532d multi_ack \ side-band-64k ofs-delta\n C: 0032want 7d1665144a3a975c05f1f43902ddaf084e784dbe\n C: 0032want 5a3f6be755bbb7deae50065988cbfa1ffa9ab68a\n @@ -367,7 +422,7 @@ entire packfile without multiplexing. Pushing Data To a Server -======================== +------------------------ Pushing data to a server will invoke the 'receive-pack' process on the server, which will allow the client to tell it which references it should |