Mercurial > public > mercurial-scm > hg
comparison mercurial/revlog.py @ 46718:ba8e508a8e69
sidedata-exchange: rewrite sidedata on-the-fly whenever possible
When a A exchanges with B, the difference of their supported sidedata categories
is made, and the responsibility is always with the client to generated it:
- If A pushes to B and B requires category `foo` that A does not have, A
will need to generate it when sending it to B.
- If A pulls from B and A needs category `foo`, it will generate `foo`
before the end of the transaction.
- Any category that is not required is removed. If peers are not compatible,
abort.
It is forbidden to rewrite sidedata for a rev that already has sidedata, since
that would introduce unreachable (garbage) data in the data file, something
we're not prepared for yet.
Differential Revision: https://phab.mercurial-scm.org/D10032
| author | Rapha?l Gom?s <rgomes@octobus.net> |
|---|---|
| date | Fri, 19 Feb 2021 11:24:50 +0100 |
| parents | c8bb7b89179e |
| children | 49fd21f32695 |
comparison
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| 46717:502e795b55ac | 46718:ba8e508a8e69 |
|---|---|
| 3203 d[b'storedsize'] = sum( | 3203 d[b'storedsize'] = sum( |
| 3204 self.opener.stat(path).st_size for path in self.files() | 3204 self.opener.stat(path).st_size for path in self.files() |
| 3205 ) | 3205 ) |
| 3206 | 3206 |
| 3207 return d | 3207 return d |
| 3208 | |
| 3209 def rewrite_sidedata(self, helpers, startrev, endrev): | |
| 3210 if self.version & 0xFFFF != REVLOGV2: | |
| 3211 return | |
| 3212 # inline are not yet supported because they suffer from an issue when | |
| 3213 # rewriting them (since it's not an append-only operation). | |
| 3214 # See issue6485. | |
| 3215 assert not self._inline | |
| 3216 if not helpers[1] and not helpers[2]: | |
| 3217 # Nothing to generate or remove | |
| 3218 return | |
| 3219 | |
| 3220 new_entries = [] | |
| 3221 # append the new sidedata | |
| 3222 with self._datafp(b'a+') as fp: | |
| 3223 # Maybe this bug still exists, see revlog._writeentry | |
| 3224 fp.seek(0, os.SEEK_END) | |
| 3225 current_offset = fp.tell() | |
| 3226 for rev in range(startrev, endrev + 1): | |
| 3227 entry = self.index[rev] | |
| 3228 new_sidedata = storageutil.run_sidedata_helpers( | |
| 3229 store=self, | |
| 3230 sidedata_helpers=helpers, | |
| 3231 sidedata={}, | |
| 3232 rev=rev, | |
| 3233 ) | |
| 3234 | |
| 3235 serialized_sidedata = sidedatautil.serialize_sidedata( | |
| 3236 new_sidedata | |
| 3237 ) | |
| 3238 if entry[8] != 0 or entry[9] != 0: | |
| 3239 # rewriting entries that already have sidedata is not | |
| 3240 # supported yet, because it introduces garbage data in the | |
| 3241 # revlog. | |
| 3242 msg = "Rewriting existing sidedata is not supported yet" | |
| 3243 raise error.Abort(msg) | |
| 3244 entry = entry[:8] | |
| 3245 entry += (current_offset, len(serialized_sidedata)) | |
| 3246 | |
| 3247 fp.write(serialized_sidedata) | |
| 3248 new_entries.append(entry) | |
| 3249 current_offset += len(serialized_sidedata) | |
| 3250 | |
| 3251 # rewrite the new index entries | |
| 3252 with self._indexfp(b'w+') as fp: | |
| 3253 fp.seek(startrev * self._io.size) | |
| 3254 for i, entry in enumerate(new_entries): | |
| 3255 rev = startrev + i | |
| 3256 self.index.replace_sidedata_info(rev, entry[8], entry[9]) | |
| 3257 packed = self._io.packentry(entry, self.node, self.version, rev) | |
| 3258 fp.write(packed) |