From 064717fcc800d9ca94366745610305d12a5532a4 Mon Sep 17 00:00:00 2001
From: Florian Fischer <florian.fischer@muhq.space>
Date: Fri, 3 May 2024 09:13:00 +0200
Subject: split lock file functions into separate file to enable testing

---
 init.lua | 87 ++++++++++------------------------------------------------------
 1 file changed, 13 insertions(+), 74 deletions(-)

(limited to 'init.lua')

diff --git a/init.lua b/init.lua
index 25735bb..5c85818 100644
--- a/init.lua
+++ b/init.lua
@@ -12,51 +12,23 @@
 -- You should have received a copy of the GNU General Public License along with
 -- vis-lockfiles found in the LICENSE file.
 -- If not, see <https://www.gnu.org/licenses/>.
+local source_str = debug.getinfo(1, 'S').source:sub(2)
+local script_path = source_str:match('(.*/)')
+
+local lockfiles = dofile(script_path .. 'lockfiles.lua')
+
 local M = {}
 M.directory = '${XDG_STATE_HOME:-${HOME}/.local/state}/vis/locks'
 M.directory_expanded = nil
 
--- Helper to execute a command and capture its output
-local function capture_cmd(cmd)
-  local p = assert(io.popen(cmd, 'r'))
-  local s = assert(p:read('*a'))
-  local success, _, status = p:close()
-  if not success then
-    local err = cmd .. ' failed with exit code: ' .. status
-    vis:info('vis-lockfiles: ' .. err)
-  end
-  return s
-end
-
 local function get_lock_dir()
   if M.directory_expanded ~= M.directory then
-    M.directory = capture_cmd('printf %s "' .. M.directory .. '"')
+    M.directory = lockfiles.capture_cmd('printf %s "' .. M.directory .. '"')
     M.directory_expanded = M.directory
   end
   return M.directory
 end
 
-local function lock_file_path(path)
-  -- escape '%' first
-  local filename = path:gsub('%%', '%%25'):gsub('/', '%%2F')
-  return get_lock_dir() .. '/' .. filename .. '.lock'
-end
-
--- determine vis' pid
-local vis_pid
-do
-  local vis_proc_file = io.open('/proc/self/stat', 'r')
-  if vis_proc_file then
-    vis_pid = vis_proc_file:read('*n')
-    vis_proc_file:close()
-
-  else -- fallback if /proc/self/stat is not available
-    local out = capture_cmd('sh -c "echo $PPID"')
-    vis_pid = tonumber(out)
-  end
-end
-assert(vis_pid)
-
 -- get a user confirmation
 -- return true if user selected yes, false otherwise
 local function confirm(path)
@@ -82,49 +54,15 @@ local function confirm(path)
 end
 
 local created_locks = {}
-local function create_lock_file(lfile_path)
-  local lock_file = io.open(lfile_path)
-  if lock_file then
-    lock_file:close()
-    return false
-  end
-
-  -- create the lock file with our pid
-  if not io.open(lfile_path, 'w') then
-    assert(os.execute('mkdir -p "' .. get_lock_dir() .. '"'))
-  end
-  lock_file = assert(io.open(lfile_path, 'w'))
-  lock_file:write(vis_pid)
-  lock_file:close()
-
-  -- detect a possible race
-  lock_file = assert(io.open(lfile_path))
-  local lock_pid = lock_file:read('*n')
-  lock_file:close()
-  local locked = tonumber(lock_pid) == vis_pid
-
-  -- remember we created the lock file
-  if locked then
-    created_locks[lfile_path] = true
-  end
-
-  return locked
-end
-
-local function delete_lock_file(lfile_path)
-  local success, err = os.remove(lfile_path)
-  if not success then
-    vis:info('vis-lockfiles: ' .. err)
-  end
-  created_locks[lfile_path] = nil
-end
 
 vis.events.subscribe(vis.events.FILE_OPEN, function(file)
   if not file.path then
     return
   end
-  local lfile_path = lock_file_path(file.path)
-  if not create_lock_file(lfile_path) and not confirm(lfile_path) then
+  local lfile_path = lockfiles.lock_file_path(get_lock_dir(), file.path)
+  if lockfiles.create_lock_file(get_lock_dir(), lfile_path) then
+    created_locks[lfile_path] = true
+  elseif not confirm(lfile_path) then
     os.exit(1)
   end
 end)
@@ -133,9 +71,10 @@ vis.events.subscribe(vis.events.FILE_CLOSE, function(file)
   if not file.path then
     return
   end
-  local lfile_path = lock_file_path(file.path)
+  local lfile_path = lockfiles.lock_file_path(get_lock_dir(), file.path)
   if created_locks[lfile_path] then
-    delete_lock_file(lfile_path)
+    lockfiles.delete_lock_file(lfile_path)
+    created_locks[lfile_path] = nil
   end
 end)
 
-- 
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