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prosody
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util/mercurial.lua @ 10571:cfeb0077c9e9
net.server_epoll: Avoid concatenating buffer with single item
Saves creating a string that'll be identical to buffer[1] anyways, as
well as a C function call. Depending on Lua version and length of the
string, this could be reusing an interned string, but a longer one would
probably be duplicated for no reason.
Having exactly one item in the buffer seems like it would be fairly
common, but I have not done an extensive study. If opportunistic writes
are enabled then it will be even more likely.
This special case could be optimized like this in table.concat but it
does not look like it is.
author | Kim Alvefur <zash@zash.se> |
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date | Sat, 28 Dec 2019 06:18:58 +0100 |
parent | 10533:a6cc5b844d7b |
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local lfs = require"lfs"; local hg = { }; function hg.check_id(path) if lfs.attributes(path, 'mode') ~= "directory" then return nil, "not a directory"; end local hg_dirstate = io.open(path.."/.hg/dirstate"); local hgid, hgrepo if hg_dirstate then hgid = ("%02x%02x%02x%02x%02x%02x"):format(hg_dirstate:read(6):byte(1, 6)); hg_dirstate:close(); local hg_changelog = io.open(path.."/.hg/store/00changelog.i"); if hg_changelog then hg_changelog:seek("set", 0x20); hgrepo = ("%02x%02x%02x%02x%02x%02x"):format(hg_changelog:read(6):byte(1, 6)); hg_changelog:close(); end else local hg_archival,e = io.open(path.."/.hg_archival.txt"); -- luacheck: ignore 211/e if hg_archival then local repo = hg_archival:read("*l"); local node = hg_archival:read("*l"); hg_archival:close() hgid = node and node:match("^node: (%x%x%x%x%x%x%x%x%x%x%x%x)") hgrepo = repo and repo:match("^repo: (%x%x%x%x%x%x%x%x%x%x%x%x)") end end return hgid, hgrepo; end return hg;