Mercurial > hg
diff tests/test-help.t @ 47077:119790e1c67c
cg4: introduce protocol flag to signify the presence of sidedata
We need a way of signaling whether the current revision has sidedata or not,
and re-using the revision flags would waste potential revlog flags and mix two
normally independent layers.
In this change, we add a single byte at the start of the ch4 delta header to
set potential protocol flags. We also reclaim the revlog flag for sidedata,
since it is no longer used, in its place now lives the (also experimental)
copytracing flag.
When generating deltas, apply the `CG_FLAG_SIDEDATA` flag if there is sidedata.
When applying the deltas, if said flag is present, the next chunk contains the
sidedata.
Differential Revision: https://phab.mercurial-scm.org/D10343
| author | Raphaël Gomès <rgomes@octobus.net> |
|---|---|
| date | Sat, 10 Apr 2021 11:27:40 +0200 |
| parents | da4e6d7a8fdd |
| children | 0470a44b9e74 |
line wrap: on
line diff
--- a/tests/test-help.t Thu Apr 08 16:34:11 2021 +0200 +++ b/tests/test-help.t Sat Apr 10 11:27:40 2021 +0200 @@ -1136,12 +1136,13 @@ the changelog data, root/flat manifest data, treemanifest data, and filelogs. - There are 3 versions of changegroups: "1", "2", and "3". From a high- + There are 4 versions of changegroups: "1", "2", "3" and "4". From a high- level, versions "1" and "2" are almost exactly the same, with the only difference being an additional item in the *delta header*. Version "3" adds support for storage flags in the *delta header* and optionally exchanging treemanifests (enabled by setting an option on the - "changegroup" part in the bundle2). + "changegroup" part in the bundle2). Version "4" adds support for + exchanging sidedata (additional revision metadata not part of the digest). Changegroups when not exchanging treemanifests consist of 3 logical segments: @@ -1208,8 +1209,8 @@ existing entry (either that the recipient already has, or previously specified in the bundle/changegroup). - The *delta header* is different between versions "1", "2", and "3" of the - changegroup format. + The *delta header* is different between versions "1", "2", "3" and "4" of + the changegroup format. Version 1 (headerlen=80): @@ -1238,6 +1239,15 @@ | | | | | | | +------------------------------------------------------------------------------+ + Version 4 (headerlen=103): + + +------------------------------------------------------------------------------+----------+ + | | | | | | | | + | node | p1 node | p2 node | base node | link node | flags | pflags | + | (20 bytes) | (20 bytes) | (20 bytes) | (20 bytes) | (20 bytes) | (2 bytes) | (1 byte) | + | | | | | | | | + +------------------------------------------------------------------------------+----------+ + The *delta data* consists of "chunklen - 4 - headerlen" bytes, which contain a series of *delta*s, densely packed (no separators). These deltas describe a diff from an existing entry (either that the recipient already @@ -1278,11 +1288,24 @@ delimited metadata defining an object stored elsewhere. Used by the LFS extension. + 4096 + Contains copy information. This revision changes files in a way that + could affect copy tracing. This does *not* affect changegroup handling, + but is relevant for other parts of Mercurial. + For historical reasons, the integer values are identical to revlog version 1 per-revision storage flags and correspond to bits being set in this 2-byte field. Bits were allocated starting from the most-significant bit, hence the reverse ordering and allocation of these flags. + The *pflags* (protocol flags) field holds bitwise flags affecting the + protocol itself. They are first in the header since they may affect the + handling of the rest of the fields in a future version. They are defined + as such: + + 1 indicates whether to read a chunk of sidedata (of variable length) right + after the revision flags. + Changeset Segment ================= @@ -1303,14 +1326,14 @@ Treemanifests Segment --------------------- - The *treemanifests segment* only exists in changegroup version "3", and - only if the 'treemanifest' param is part of the bundle2 changegroup part - (it is not possible to use changegroup version 3 outside of bundle2). - Aside from the filenames in the *treemanifests segment* containing a - trailing "/" character, it behaves identically to the *filelogs segment* - (see below). The final sub-segment is followed by an *empty chunk* - (logically, a sub-segment with filename size 0). This denotes the boundary - to the *filelogs segment*. + The *treemanifests segment* only exists in changegroup version "3" and + "4", and only if the 'treemanifest' param is part of the bundle2 + changegroup part (it is not possible to use changegroup version 3 or 4 + outside of bundle2). Aside from the filenames in the *treemanifests + segment* containing a trailing "/" character, it behaves identically to + the *filelogs segment* (see below). The final sub-segment is followed by + an *empty chunk* (logically, a sub-segment with filename size 0). This + denotes the boundary to the *filelogs segment*. Filelogs Segment ================ @@ -3648,12 +3671,13 @@ filelogs. </p> <p> - There are 3 versions of changegroups: "1", "2", and "3". From a + There are 4 versions of changegroups: "1", "2", "3" and "4". From a high-level, versions "1" and "2" are almost exactly the same, with the only difference being an additional item in the *delta header*. Version "3" adds support for storage flags in the *delta header* and optionally exchanging treemanifests (enabled by setting an option on the - "changegroup" part in the bundle2). + "changegroup" part in the bundle2). Version "4" adds support for exchanging + sidedata (additional revision metadata not part of the digest). </p> <p> Changegroups when not exchanging treemanifests consist of 3 logical @@ -3733,8 +3757,8 @@ bundle/changegroup). </p> <p> - The *delta header* is different between versions "1", "2", and - "3" of the changegroup format. + The *delta header* is different between versions "1", "2", "3" and "4" + of the changegroup format. </p> <p> Version 1 (headerlen=80): @@ -3770,6 +3794,17 @@ +------------------------------------------------------------------------------+ </pre> <p> + Version 4 (headerlen=103): + </p> + <pre> + +------------------------------------------------------------------------------+----------+ + | | | | | | | | + | node | p1 node | p2 node | base node | link node | flags | pflags | + | (20 bytes) | (20 bytes) | (20 bytes) | (20 bytes) | (20 bytes) | (2 bytes) | (1 byte) | + | | | | | | | | + +------------------------------------------------------------------------------+----------+ + </pre> + <p> The *delta data* consists of "chunklen - 4 - headerlen" bytes, which contain a series of *delta*s, densely packed (no separators). These deltas describe a diff from an existing entry (either that the recipient already has, or previously @@ -3808,6 +3843,8 @@ <dd>Ellipsis revision. Revision hash does not match data (likely due to rewritten parents). <dt>8192 <dd>Externally stored. The revision fulltext contains "key:value" "\n" delimited metadata defining an object stored elsewhere. Used by the LFS extension. + <dt>4096 + <dd>Contains copy information. This revision changes files in a way that could affect copy tracing. This does *not* affect changegroup handling, but is relevant for other parts of Mercurial. </dl> <p> For historical reasons, the integer values are identical to revlog version 1 @@ -3815,6 +3852,15 @@ field. Bits were allocated starting from the most-significant bit, hence the reverse ordering and allocation of these flags. </p> + <p> + The *pflags* (protocol flags) field holds bitwise flags affecting the protocol + itself. They are first in the header since they may affect the handling of the + rest of the fields in a future version. They are defined as such: + </p> + <dl> + <dt>1 indicates whether to read a chunk of sidedata (of variable length) right + <dd>after the revision flags. + </dl> <h2>Changeset Segment</h2> <p> The *changeset segment* consists of a single *delta group* holding @@ -3832,9 +3878,9 @@ </p> <h3>Treemanifests Segment</h3> <p> - The *treemanifests segment* only exists in changegroup version "3", and - only if the 'treemanifest' param is part of the bundle2 changegroup part - (it is not possible to use changegroup version 3 outside of bundle2). + The *treemanifests segment* only exists in changegroup version "3" and "4", + and only if the 'treemanifest' param is part of the bundle2 changegroup part + (it is not possible to use changegroup version 3 or 4 outside of bundle2). Aside from the filenames in the *treemanifests segment* containing a trailing "/" character, it behaves identically to the *filelogs segment* (see below). The final sub-segment is followed by an *empty chunk* (logically,