[patch] Add ldap completer

[Matthew Martin <phy1729@gmail.com>]

OpenBSD recently gained an ldap command. This is my first stab at
completing it.

For the protocol _describe, is -I correct? I don't grok the differences
between the prefixes and suffixes. For host is -S '' correct for not
adding a space after and should the completer avoid adding the space?

The ldapi protocol is not completed correctly because I don't know how
to make _files replace / with %2f.

(N.B. The URL pattern below is correct by RFC, I'll submit a patch for
the OpenBSD man page soon.)

- Matthew Martin

diff --git a/Completion/BSD/Command/_ldap b/Completion/BSD/Command/_ldap
new file mode 100644
index 000000000..ba8b981b4
--- /dev/null
+++ b/Completion/BSD/Command/_ldap
@@ -0,0 +1,79 @@
+#compdef ldap
+
+local -a commands scopes
+commands=(
+  search:'search a directory'
+)
+scopes=(
+  base:'base object only'
+  one:'one level'
+  sub:subtree
+)
+
+_ldap_url() {
+  local -a expl protocols tags
+  protocols=(
+    ldap:'TCP in plaintext'
+    ldaps:'TLS'
+    ldap+tls:'TCP and use StartTLS'
+    ldapi:'connect to a socket'
+  )
+
+  # [protocol://]host[:port][/basedn[?[attribute,...][?[scope][?[filter]]]]]
+  if ! compset -P '*://'; then
+    tags=(protocol)
+  fi
+
+  if ! compset -P '*/'; then
+    if compset -P '*:'; then
+      tags=(port)
+    else
+      tags+=(host)
+    fi
+  else
+    case $PREFIX in
+      *\?*\?*\?*) tags=(filter);;
+      *\?*\?*) tags=(scope);;
+      *\?*) tags=(attribute);;
+      *) tags=(basedn);;
+    esac
+    compset -P '*\?'
+  fi
+
+  _tags $tags
+  while _tags; do
+    _requested protocol && _describe -t protocol protocol protocols -I ://
+    _requested host && _hosts -S ''
+    _requested port && _guard '|<1-65535>' port
+    _requested basedn expl 'base DN'
+    _requested attribute expl attribute
+    _requested scope && _describe -t scope scope scopes
+    _requested filter expl filter
+  done
+}
+
+if (( CURRENT == 2 )); then
+  _describe command commands
+else
+  shift words; (( CURRENT-- ))
+  case $words[1] in
+    search)
+      _arguments -s -S -A '-*' \
+        '-b+[specify base DN]:base DN:' \
+        '-c+[specify CA file]:CA file:' \
+        '-D+[specify bind DN]:bind DN:' \
+        '-H+[specify URL]: :_ldap_url' \
+        '-L[output in LDIF]' \
+        '-l+[specify time limit or 0 for no limit]:time limit [0]:' \
+        '-s+[specify scope]:scope [sub]:(($scopes))' \
+        '-v[be verbose]' \
+        '-W[prompt for bind secret]' \
+        '-w+[specify bind secret]:bind secret:' \
+        '-x[use simple authentication]' \
+        '-Z[use StartTLS]' \
+        '-z+[specify maximum number of results or 0 for no limit]:size limit [0]:' \
+        ':: :_guard "*=*" "filter"' \
+        '*:attribute:'
+      ;;
+  esac
+fi