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1c9b659d98
The spec is very inconsistent about which PKT-LINE() parts of the grammar include a LF. On top of that, the code is not consistent, either (e.g., send-pack does not put newlines into the ref-update commands it sends). Let's make explicit the long-standing expectation that we generally expect pkt-lines to end in a newline, but that receivers should be lenient. This makes the spec consistent, and matches what git already does (though it does not always fulfill the SHOULD). We do make an exception for the push-cert, where the receiving code is currently a bit pickier. This is a reasonable way to be, as the data needs to be byte-for-byte compatible with what was signed. We _could_ make up some rules about signing a canonicalized version including newlines, but that would require a code change, and is out of scope for this patch. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
100 lines
2.9 KiB
Plaintext
100 lines
2.9 KiB
Plaintext
Documentation Common to Pack and Http Protocols
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===============================================
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ABNF Notation
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-------------
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ABNF notation as described by RFC 5234 is used within the protocol documents,
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except the following replacement core rules are used:
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----
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HEXDIG = DIGIT / "a" / "b" / "c" / "d" / "e" / "f"
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----
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We also define the following common rules:
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----
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NUL = %x00
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zero-id = 40*"0"
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obj-id = 40*(HEXDIGIT)
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refname = "HEAD"
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refname /= "refs/" <see discussion below>
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----
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A refname is a hierarchical octet string beginning with "refs/" and
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not violating the 'git-check-ref-format' command's validation rules.
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More specifically, they:
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. They can include slash `/` for hierarchical (directory)
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grouping, but no slash-separated component can begin with a
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dot `.`.
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. They must contain at least one `/`. This enforces the presence of a
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category like `heads/`, `tags/` etc. but the actual names are not
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restricted.
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. They cannot have two consecutive dots `..` anywhere.
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. They cannot have ASCII control characters (i.e. bytes whose
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values are lower than \040, or \177 `DEL`), space, tilde `~`,
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caret `^`, colon `:`, question-mark `?`, asterisk `*`,
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or open bracket `[` anywhere.
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. They cannot end with a slash `/` or a dot `.`.
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. They cannot end with the sequence `.lock`.
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. They cannot contain a sequence `@{`.
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. They cannot contain a `\\`.
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pkt-line Format
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---------------
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Much (but not all) of the payload is described around pkt-lines.
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A pkt-line is a variable length binary string. The first four bytes
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of the line, the pkt-len, indicates the total length of the line,
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in hexadecimal. The pkt-len includes the 4 bytes used to contain
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the length's hexadecimal representation.
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A pkt-line MAY contain binary data, so implementors MUST ensure
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pkt-line parsing/formatting routines are 8-bit clean.
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A non-binary line SHOULD BE terminated by an LF, which if present
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MUST be included in the total length. Receivers MUST treat pkt-lines
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with non-binary data the same whether or not they contain the trailing
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LF (stripping the LF if present, and not complaining when it is
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missing).
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The maximum length of a pkt-line's data component is 65520 bytes.
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Implementations MUST NOT send pkt-line whose length exceeds 65524
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(65520 bytes of payload + 4 bytes of length data).
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Implementations SHOULD NOT send an empty pkt-line ("0004").
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A pkt-line with a length field of 0 ("0000"), called a flush-pkt,
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is a special case and MUST be handled differently than an empty
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pkt-line ("0004").
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----
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pkt-line = data-pkt / flush-pkt
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data-pkt = pkt-len pkt-payload
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pkt-len = 4*(HEXDIG)
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pkt-payload = (pkt-len - 4)*(OCTET)
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flush-pkt = "0000"
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----
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Examples (as C-style strings):
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----
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pkt-line actual value
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---------------------------------
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"0006a\n" "a\n"
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"0005a" "a"
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"000bfoobar\n" "foobar\n"
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"0004" ""
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----
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