Documentation / technical / api-sub-process.txton commit Merge branch 'ah/patch-id-doc' (62ebe03)
   1sub-process API
   2===============
   3
   4The sub-process API makes it possible to run background sub-processes
   5for the entire lifetime of a Git invocation. If Git needs to communicate
   6with an external process multiple times, then this can reduces the process
   7invocation overhead. Git and the sub-process communicate through stdin and
   8stdout.
   9
  10The sub-processes are kept in a hashmap by command name and looked up
  11via the subprocess_find_entry function.  If an existing instance can not
  12be found then a new process should be created and started.  When the
  13parent git command terminates, all sub-processes are also terminated.
  14
  15This API is based on the run-command API.
  16
  17Data structures
  18---------------
  19
  20* `struct subprocess_entry`
  21
  22The sub-process structure.  Members should not be accessed directly.
  23
  24Types
  25-----
  26
  27'int(*subprocess_start_fn)(struct subprocess_entry *entry)'::
  28
  29        User-supplied function to initialize the sub-process.  This is
  30        typically used to negotiate the interface version and capabilities.
  31
  32
  33Functions
  34---------
  35
  36`cmd2process_cmp`::
  37
  38        Function to test two subprocess hashmap entries for equality.
  39
  40`subprocess_start`::
  41
  42        Start a subprocess and add it to the subprocess hashmap.
  43
  44`subprocess_stop`::
  45
  46        Kill a subprocess and remove it from the subprocess hashmap.
  47
  48`subprocess_find_entry`::
  49
  50        Find a subprocess in the subprocess hashmap.
  51
  52`subprocess_get_child_process`::
  53
  54        Get the underlying `struct child_process` from a subprocess.
  55
  56`subprocess_read_status`::
  57
  58        Helper function to read packets looking for the last "status=<foo>"
  59        key/value pair.