Andrew's git - gitweb.git/blob

   1#ifndef SUBPROCESS_H
   2#define SUBPROCESS_H
   3
   4#include "git-compat-util.h"
   5#include "hashmap.h"
   6#include "run-command.h"
   7
   8/*
   9 * The sub-process API makes it possible to run background sub-processes
  10 * for the entire lifetime of a Git invocation. If Git needs to communicate
  11 * with an external process multiple times, then this can reduces the process
  12 * invocation overhead. Git and the sub-process communicate through stdin and
  13 * stdout.
  14 *
  15 * The sub-processes are kept in a hashmap by command name and looked up
  16 * via the subprocess_find_entry function.  If an existing instance can not
  17 * be found then a new process should be created and started.  When the
  18 * parent git command terminates, all sub-processes are also terminated.
  19 *
  20 * This API is based on the run-command API.
  21 */
  22
  23 /* data structures */
  24
  25/* Members should not be accessed directly. */
  26struct subprocess_entry {
  27        struct hashmap_entry ent; /* must be the first member! */
  28        const char *cmd;
  29        struct child_process process;
  30};
  31
  32/* subprocess functions */
  33
  34/* Function to test two subprocess hashmap entries for equality. */
  35extern int cmd2process_cmp(const void *unused_cmp_data,
  36                           const struct subprocess_entry *e1,
  37                           const struct subprocess_entry *e2,
  38                           const void *unused_keydata);
  39
  40/*
  41 * User-supplied function to initialize the sub-process.  This is
  42 * typically used to negotiate the interface version and capabilities.
  43 */
  44typedef int(*subprocess_start_fn)(struct subprocess_entry *entry);
  45
  46/* Start a subprocess and add it to the subprocess hashmap. */
  47int subprocess_start(struct hashmap *hashmap, struct subprocess_entry *entry, const char *cmd,
  48                subprocess_start_fn startfn);
  49
  50/* Kill a subprocess and remove it from the subprocess hashmap. */
  51void subprocess_stop(struct hashmap *hashmap, struct subprocess_entry *entry);
  52
  53/* Find a subprocess in the subprocess hashmap. */
  54struct subprocess_entry *subprocess_find_entry(struct hashmap *hashmap, const char *cmd);
  55
  56/* subprocess helper functions */
  57
  58/* Get the underlying `struct child_process` from a subprocess. */
  59static inline struct child_process *subprocess_get_child_process(
  60                struct subprocess_entry *entry)
  61{
  62        return &entry->process;
  63}
  64
  65/*
  66 * Helper function that will read packets looking for "status=<foo>"
  67 * key/value pairs and return the value from the last "status" packet
  68 */
  69
  70int subprocess_read_status(int fd, struct strbuf *status);
  71
  72#endif