Add spawn_once function

api/lua/example_config.lua

@@ -41,18 +41,4 @@ require("pinnacle").setup(function(pinnacle)
     input.keybind({ "Ctrl" }, keys.KEY_3, function()
         process.spawn("nautilus")
     end)
-
-    input.keybind({ "Ctrl", "Alt" }, keys.w, function()
-        local win = client.get_window("focus")
-        win:set_size({ w = 500, h = 500 })
-    end)
-
-    input.keybind({ "Ctrl", "Alt" }, keys.e, function()
-        local windows = client.get_windows()
-        for k, v in pairs(windows) do
-            for k2, v2 in pairs(v) do
-                print(k2 .. ": " .. tostring(v2))
-            end
-        end
-    end)
 end)

api/lua/process.lua

@@ -8,7 +8,7 @@
 
 local process = {}
 
----Spawn a process with an optional callback for its stdout and stderr.
+---Spawn a process with an optional callback for its stdout, stderr, and exit information.
 ---
 ---`callback` has the following parameters:
 --- - `stdout`: The process's stdout printed this line.
@@ -47,4 +47,31 @@ function process.spawn(command, callback)
     })
 end
 
+---Spawn a process only if it isn't already running, with an optional callback for its stdout, stderr, and exit information.
+---
+---`callback` has the following parameters:
+--- - `stdout`: The process's stdout printed this line.
+--- - `stderr`: The process's stderr printed this line.
+--- - `exit_code`: The process exited with this code.
+--- - `exit_msg`: The process exited with this message.
+---
+---`spawn_once` checks for the process using `pgrep`. If your system doesn't have `pgrep`, this won't work properly.
+---@param command string|string[] The command as one whole string or a table of each of its arguments
+---@param callback fun(stdout: string|nil, stderr: string|nil, exit_code: integer|nil, exit_msg: string|nil)? A callback to do something whenever the process's stdout or stderr print a line, or when the process exits.
+function process.spawn_once(command, callback)
+    local proc = ""
+    if type(command) == "string" then
+        proc = command:match("%S+")
+    else
+        proc = command[1]
+    end
+
+    ---@type string
+    local procs = io.popen("pgrep -f " .. proc):read("*a")
+    if procs:len() ~= 0 then -- if process exists, return
+        return
+    end
+    process.spawn(command, callback)
+end
+
 return process