Add bash autocompletion script for standalone executable

resources/complete.lua

@@ -0,0 +1,139 @@
+#!/usr/bin/lua5.2
+
+-- CivetWeb command line completion for bash
+--
+-- To use it, create a file called "civetweb" in the completion folder
+-- (/usr/share/bash-completion/completions/ or /etc/bash_completion)
+-- This file has to contain just one line:
+-- complete -C /path/to/civetweb/resources/complete.lua civetweb
+--
+
+-- The bash "complete -C" has an awkward interface:
+-- see https://unix.stackexchange.com/questions/250262/how-to-use-bashs-complete-or-compgen-c-command-option
+-- Command line arguments
+cmd = arg[1] -- typically "./civetweb" or whatever path was used
+this = arg[2] -- characters already typed for the next options
+last = arg[3] -- option before this one
+-- Environment variables
+comp_line = os.getenv("COMP_LINE") -- entire command line
+comp_point = os.getenv("COMP_POINT") -- position of cursor (index)
+comp_type = os.getenv("COMP_TYPE") -- type:
+-- 9 for normal completion
+-- 33 when listing alternatives on ambiguous completions
+-- 37 for menu completion
+-- 63 when tabbing between ambiguous completions
+-- 64 to list completions after a partial completion
+
+
+-- Debug-Print function (must use absolute path for log file)
+function dp(txt)
+  local f = io.open("/tmp/complete.log", "a");
+  f:write(txt .. "\n")
+  f:close()
+end
+
+-- Helper function: Check if files exist
+function fileexists(name)
+  local f = io.open(name, "r")
+  if f then
+    f:close()
+    return true
+  end
+  return false
+end
+
+
+-- Debug logging
+dp("complete: cmd=" .. cmd .. ", this=" .. this .. ", last=" .. last .. ", type=" .. comp_type)
+
+
+-- Trim command line (remove spaces)
+trim_comp_line = string.match(comp_line, "^%s*(.-)%s*$")
+ 
+if (trim_comp_line == cmd) then
+  -- this is the first option
+  dp("Suggest --help argument")
+  print("--help ")
+  os.exit(0)
+end
+
+is_h = string.find(comp_line, "^%s*" .. cmd .. "%s+%-h%s")
+is_h = is_h or string.find(comp_line, "^%s*" .. cmd .. "%s+%--help%s")
+is_h = is_h or string.find(comp_line, "^%s*" .. cmd .. "%s+%-H%s")
+
+if (is_h) then
+  dp("If --help is used, no additional argument is allowed")
+  os.exit(0)
+end
+
+is_a = string.find(comp_line, "^%s*" .. cmd .. "%s+%-A%s")
+is_c = string.find(comp_line, "^%s*" .. cmd .. "%s+%-C%s")
+is_i = string.find(comp_line, "^%s*" .. cmd .. "%s+%-I%s")
+is_r = string.find(comp_line, "^%s*" .. cmd .. "%s+%-R%s")
+
+if (is_i) then
+  dp("If --I is used, no additional argument is allowed")
+  os.exit(0)
+end
+
+-- -A and -R require the password file as second argument
+htpasswd = ".htpasswd"
+if ((last == "-A") or (last == "-R")) and (this == htpasswd:sub(1,#this)) then
+  print(htpasswd)
+  os.exit(0)
+end
+
+-- -C requires an URL, usually starting with http:// or https://
+http = "http://"
+if (last == "-C") and (this == http:sub(1,#this)) then
+  print(http)
+  print(http.. "localhost/")
+  os.exit(0)
+end
+http = "https://"
+if (last == "-C") and (this == http:sub(1,#this)) then
+  print(http)
+  print(http.. "localhost/")
+  os.exit(0)
+end
+
+
+-- Take options directly from "--help" output of executable
+optfile = "/tmp/civetweb.options"
+if not fileexists(optfile) then
+  dp("options file " .. optfile .. " missing")
+  os.execute(cmd .. " -h &> " .. optfile)
+else
+  dp("options file " .. optfile .. " found")
+end
+
+for l in io.lines(optfile) do
+  local lkey, lval = l:match("^%s+(%-[^%s]*)%s*([^%s]*)%s*$")
+  if lkey then
+    local thislen = string.len(this)
+    if (thislen>0) and (this == lkey:sub(1,thislen)) then
+      print(lkey)
+      dp("match: " .. lkey)
+      keymatch = true
+    end
+    if last == lkey then
+      valmatch = lval
+    end
+  end
+end
+
+if keymatch then
+  -- at least one options matches
+  os.exit(0)
+end
+
+if valmatch then
+  -- suggest the default value
+  print(valmatch)
+  os.exit(0)
+end
+
+-- No context to determine next argument
+dp("no specific option")
+os.exit(0)
+

src/main.c

@@ -279,7 +279,7 @@ show_usage_and_exit(const char *exeName)
 	fprintf(stderr, "    %s [config_file]\n", exeName);
 	fprintf(stderr, "    %s [-option value ...]\n", exeName);
 	fprintf(stderr, "  Run as client:\n");
-	fprintf(stderr, "    %s -C\n", exeName);
+	fprintf(stderr, "    %s -C url\n", exeName);
 	fprintf(stderr, "  Show system information:\n");
 	fprintf(stderr, "    %s -I\n", exeName);
 	fprintf(stderr, "  Add user/change password:\n");