From: "Martin Ågren" <martin.agren@gmail.com>
To: "brian m. carlson" <sandals@crustytoothpaste.net>
Cc: git@vger.kernel.org, Derrick Stolee <stolee@gmail.com>,
Junio C Hamano <gitster@pobox.com>
Subject: [PATCH 2/5] index-format.txt: document SHA-256 index format
Date: Fri, 14 Aug 2020 14:21:43 +0200 [thread overview]
Message-ID: <e811455d55cdb222a85d880f3cf3d5e28a8d4c91.1597406877.git.martin.agren@gmail.com> (raw)
In-Reply-To: <cover.1597406877.git.martin.agren@gmail.com>
Similar to a recent commit, document that in SHA-1 repositories, we use
SHA-1 and in SHA-256 repositories, we use SHA-256, then replace all
other uses of "SHA-1" with something more neutral.
Signed-off-by: Martin Ågren <martin.agren@gmail.com>
---
Documentation/technical/index-format.txt | 27 +++++++++++++-----------
1 file changed, 15 insertions(+), 12 deletions(-)
diff --git a/Documentation/technical/index-format.txt b/Documentation/technical/index-format.txt
index faa25c5c52..827ece2ed1 100644
--- a/Documentation/technical/index-format.txt
+++ b/Documentation/technical/index-format.txt
@@ -3,8 +3,11 @@ Git index format
== The Git index file has the following format
- All binary numbers are in network byte order. Version 2 is described
- here unless stated otherwise.
+ All binary numbers are in network byte order.
+ In a repository using the traditional SHA-1, checksums and object IDs
+ (object names) mentioned below are all computed using SHA-1. Similarly,
+ in SHA-256 repositories, these values are computed using SHA-256.
+ Version 2 is described here unless stated otherwise.
- A 12-byte header consisting of
@@ -32,7 +35,7 @@ Git index format
Extension data
- - 160-bit SHA-1 over the content of the index file before this
+ - 160-bit hash checksum over the content of the index file before this
checksum.
== Index entry
@@ -80,7 +83,7 @@ Git index format
32-bit file size
This is the on-disk size from stat(2), truncated to 32-bit.
- 160-bit SHA-1 for the represented object
+ 160-bit object name for the represented object
A 16-bit 'flags' field split into (high to low bits)
@@ -211,8 +214,8 @@ Git index format
The extension consists of:
- - 160-bit SHA-1 of the shared index file. The shared index file path
- is $GIT_DIR/sharedindex.<SHA-1>. If all 160 bits are zero, the
+ - Hash of the shared index file. The shared index file path
+ is $GIT_DIR/sharedindex.<hash>. If all bits are zero, the
index does not require a shared index file.
- An ewah-encoded delete bitmap, each bit represents an entry in the
@@ -253,10 +256,10 @@ Git index format
- 32-bit dir_flags (see struct dir_struct)
- - 160-bit SHA-1 of $GIT_DIR/info/exclude. Null SHA-1 means the file
+ - Hash of $GIT_DIR/info/exclude. A null hash means the file
does not exist.
- - 160-bit SHA-1 of core.excludesfile. Null SHA-1 means the file does
+ - Hash of core.excludesfile. A null hash means the file does
not exist.
- NUL-terminated string of per-dir exclude file name. This usually
@@ -285,13 +288,13 @@ The remaining data of each directory block is grouped by type:
- An ewah bitmap, the n-th bit records "check-only" bit of
read_directory_recursive() for the n-th directory.
- - An ewah bitmap, the n-th bit indicates whether SHA-1 and stat data
+ - An ewah bitmap, the n-th bit indicates whether hash and stat data
is valid for the n-th directory and exists in the next data.
- An array of stat data. The n-th data corresponds with the n-th
"one" bit in the previous ewah bitmap.
- - An array of SHA-1. The n-th SHA-1 corresponds with the n-th "one" bit
+ - An array of hashes. The n-th hash corresponds with the n-th "one" bit
in the previous ewah bitmap.
- One NUL.
@@ -330,12 +333,12 @@ The remaining data of each directory block is grouped by type:
- 32-bit offset to the end of the index entries
- - 160-bit SHA-1 over the extension types and their sizes (but not
+ - Hash over the extension types and their sizes (but not
their contents). E.g. if we have "TREE" extension that is N-bytes
long, "REUC" extension that is M-bytes long, followed by "EOIE",
then the hash would be:
- SHA-1("TREE" + <binary representation of N> +
+ Hash("TREE" + <binary representation of N> +
"REUC" + <binary representation of M>)
== Index Entry Offset Table
--
2.28.0.277.g9b3c35fffd
next prev parent reply other threads:[~2020-08-14 12:22 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-08-13 22:48 [PATCH 0/2] Documentation updates for SHA-256 brian m. carlson
2020-08-13 22:49 ` [PATCH 1/2] docs: document SHA-256 pack and indices brian m. carlson
2020-08-14 2:26 ` Derrick Stolee
2020-08-13 22:49 ` [PATCH 2/2] docs: fix step in transition plan brian m. carlson
2020-08-14 12:21 ` Martin Ågren
2020-08-14 2:33 ` [PATCH 0/2] Documentation updates for SHA-256 Derrick Stolee
2020-08-14 4:47 ` Junio C Hamano
2020-08-14 20:20 ` brian m. carlson
2020-08-14 20:25 ` Junio C Hamano
2020-08-14 12:21 ` [PATCH 0/5] more SHA-256 documentation Martin Ågren
2020-08-14 12:21 ` [PATCH 1/5] http-protocol.txt: document SHA-256 "want"/"have" format Martin Ågren
2020-08-14 17:28 ` Junio C Hamano
2020-08-14 20:23 ` brian m. carlson
2020-08-14 20:32 ` Martin Ågren
2020-08-14 20:39 ` Junio C Hamano
2020-08-14 20:47 ` Junio C Hamano
2020-08-14 12:21 ` Martin Ågren [this message]
2020-08-14 12:28 ` [PATCH 2/5] index-format.txt: document SHA-256 index format Derrick Stolee
2020-08-14 14:05 ` Martin Ågren
2020-08-14 12:21 ` [PATCH 3/5] protocol-capabilities.txt: clarify "allow-x-sha1-in-want" re SHA-256 Martin Ågren
2020-08-14 12:31 ` Derrick Stolee
2020-08-14 14:05 ` Martin Ågren
2020-08-14 17:33 ` Junio C Hamano
2020-08-14 20:35 ` Martin Ågren
2020-08-14 20:43 ` Junio C Hamano
2020-08-14 12:21 ` [PATCH 4/5] shallow.txt: document SHA-256 shallow format Martin Ågren
2020-08-14 12:21 ` [PATCH 5/5] commit-graph-format.txt: fix "Hash Version" description Martin Ågren
2020-08-14 12:37 ` Derrick Stolee
2020-08-14 14:10 ` Martin Ågren
2020-08-14 20:28 ` [PATCH 0/5] more SHA-256 documentation brian m. carlson
2020-08-15 16:05 ` [PATCH v2 0/4] " Martin Ågren
2020-08-15 16:05 ` [PATCH v2 1/4] http-protocol.txt: document SHA-256 "want"/"have" format Martin Ågren
2020-08-15 16:06 ` [PATCH v2 2/4] index-format.txt: document SHA-256 index format Martin Ågren
2020-08-15 16:06 ` [PATCH v2 3/4] protocol-capabilities.txt: clarify "allow-x-sha1-in-want" re SHA-256 Martin Ågren
2020-08-15 16:06 ` [PATCH v2 4/4] shallow.txt: document SHA-256 shallow format Martin Ågren
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