I've been playing a bit with lua. It's an embedded scripting language
with strong c integration. It's small and fast.
The interesting feature would be to run C-functions direct inside lua. I
suppose that would increase speed even more, at the same time as we have
the convinence of a interpreted language. Lua is smaller and faster
(well as always, it depends on what you're doing) than python and ruby.
Perl is a really pain for the windows folks (I've heard).
A correct implementation for lua support would be to start a
lua-interpreter from inside git.c (or somewhere) and load the lua code
for a specific command. That would make us independent of any target
installation of lua (althought the git binary would increase with the
lua library around 300 kb).
However I did a quick test using lua as a replacement for sh (without
direct calls to c-functions) and the result is impressive. (However this
is the wrong way of using lua, shell scripting is not something lua is
good at).
I did some runs on a project with 52 submodules (or 53 if you count the
ones in .gitmodules). These results are pretty typical:
iveqy@kolya:~/projects/eracle_core$ time /home/iveqy/projects/git/git-submodule.lua > /dev/null
real 0m1.665s
user 0m0.276s
sys 0m0.452s
iveqy@kolya:~/projects/eracle_core$ time git submodule > /dev/null
real 0m3.413s
user 0m0.476s
sys 0m1.224s
For me, that speedup does matter.
NOTICE!!!
This code is experimental. It does have some known bugs, it does have
some style issues. A state of the art complete implementation would
contain a few more tests/jumps and less concat (which is extremely
expensive in lua) and less git-invokation.
Signed-off-by: Fredrik Gustafsson <iveqy@xxxxxxxxx>
---
git-submodule.lua | 104 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 104 insertions(+)
create mode 100755 git-submodule.lua
diff --git a/git-submodule.lua b/git-submodule.lua
new file mode 100755
index 0000000..14f71e6
--- /dev/null
+++ b/git-submodule.lua
@@ -0,0 +1,104 @@
+#!/usr/bin/lua
+
+function run_cmd(cmd)
+ local f = io.popen(cmd, 'r');
+ local out = f:read('*a');
+ f:close()
+ return out
+end
+
+function fwrite(fmt, ...)
+ return io.write(string.format(fmt, ...))
+end
+
+function read_gitmodules()
+ local inf = assert(io.open('.gitmodules', 'r'))
+ local config = inf:read("*all")
+ gitmodules = {}
+ for sm in string.gmatch(config, '%[[^]]*%][^%[]*') do
+ local thismod = {}
+ local name = string.match(sm, '%[%s-submodule%s-"(.+)"%s-%]')
+ thismod["name"] = name
+ local path = ''
+ for k, v in string.gmatch(sm, '\n%s*([^=^%s]*)%s*=%s*([^\n]*)') do
+ if k == 'path' then
+ path = v
+ else
+ thismod[k] = v
+ end
+ end
+ if path == '' then
+ fwrite("No path found for %s in .gitmodules\n", name)
+ os.exit(1)
+ end
+ gitmodules[path] = thismod
+ end
+
+ return gitmodules
+end
+
+function module_list()
+ local lsfiles = 'git ls-files --stage --error-unmatch -z || echo "#unmatched"'
+ local out = run_cmd(lsfiles)
+ local unmerged = ''
+ local subs = read_gitmodules()
+
+ for row in string.gmatch(out, '.-\0') do
+ if row == '#unmatched' then
+ os.exit(1)
+ end
+
+ local mode, sha1, stage, path = string.match(row, '(%d+)%s([0-9a-f]+)%s(.)%s(.*)\0')
+ if mode == '160000' then
+ if stage == '0' then
+ subs[path]["sha1"] = sha1
+ subs[path]["stage"] = stage
+ else
+ if unmerged ~= path then
+ local null_sha1 = '0000000000000000000000000000000000000000'
+ subs[path]["sha1"] = null_sha1
+ subs[path]["stage"] = 'U'
+ end
+ unmerged = path
+ end
+ end
+ end
+ return subs
+end
+
+function get_name_rev(path, sha1)
+ if sha1 == nil then sha1="" end
+ local cmd = "cd \"" .. path .. "\" && (git describe " .. sha1 ..
+ " 2>/dev/null || git describe --tags " .. sha1 ..
+ " 2>/dev/null || git describe --contains " .. sha1 ..
+ " 2>/dev/null || git describe --all --always " .. sha1 ..
+ " 2>/dev/null) "
+ return string.gsub(run_cmd(cmd), '\n', '')
+end
+
+function cmd_status()
+ subs = module_list()
+ for smpath in pairs(subs) do
+ if (subs[smpath].sha1) then
+ if subs[smpath].stage == 'U' then
+ subs[smpath]["revname"] = get_name_rev(smpath, subs[smpath].sha1)
+ fwrite("U%s %s (%s)", subs[smpath].sha1, smpath, subs[smpath].revname)
+ elseif run_cmd("test -z " .. subs[smpath].url .. " || ! test -d " .. smpath .."/.git -o -f " .. smpath .. "/.git || echo '0' ") ~= '0\n' then
+ subs[smpath]["revname"] = get_name_rev(smpath, subs[smpath].sha1)
+ fwrite("-%s %s (%s)\n", subs[smpath].sha1, smpath, subs[smpath].revname)
+ elseif run_cmd("git diff-files --ignore-submodules=dirty --quiet -- " .. smpath .. " || echo '0'") ~= '0\n' then
+ p = run_cmd("git diff-files --ignore-submodules=dirty --quiet -- " .. smpath .. " || echo '0'")
+ subs[smpath]["revname"] = get_name_rev(smpath, subs[smpath].sha1)
+ fwrite(" %s %s (%s)\n", subs[smpath].sha1, smpath, subs[smpath].revname)
+ else
+ subs[smpath].sha1 = string.gsub(run_cmd('cd ' .. smpath .. ' && git rev-parse --verify HEAD'), "\n", "")
+ subs[smpath]["revname"] = get_name_rev(smpath, subs[smpath].sha1)
+ fwrite("+%s %s (%s)\n", subs[smpath].sha1, smpath, subs[smpath].revname)
+ end
+ end
+ end
+end
+
+if arg[1] == nil or arg[1] == 'status' then
+ cmd_status()
+end
--
1.8.3.1.381.g2ab719e.dirty
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