run-command.hon commit git-p4: Unset P4DIFF environment variable when using 'p4 -du diff' (67abd41)
   1#ifndef RUN_COMMAND_H
   2#define RUN_COMMAND_H
   3
   4enum {
   5        ERR_RUN_COMMAND_FORK = 10000,
   6        ERR_RUN_COMMAND_EXEC,
   7        ERR_RUN_COMMAND_PIPE,
   8        ERR_RUN_COMMAND_WAITPID,
   9        ERR_RUN_COMMAND_WAITPID_WRONG_PID,
  10        ERR_RUN_COMMAND_WAITPID_SIGNAL,
  11        ERR_RUN_COMMAND_WAITPID_NOEXIT,
  12};
  13
  14struct child_process {
  15        const char **argv;
  16        pid_t pid;
  17        /*
  18         * Using .in, .out, .err:
  19         * - Specify 0 for no redirections (child inherits stdin, stdout,
  20         *   stderr from parent).
  21         * - Specify -1 to have a pipe allocated as follows:
  22         *     .in: returns the writable pipe end; parent writes to it,
  23         *          the readable pipe end becomes child's stdin
  24         *     .out, .err: returns the readable pipe end; parent reads from
  25         *          it, the writable pipe end becomes child's stdout/stderr
  26         *   The caller of start_command() must close the returned FDs
  27         *   after it has completed reading from/writing to it!
  28         * - Specify > 0 to set a channel to a particular FD as follows:
  29         *     .in: a readable FD, becomes child's stdin
  30         *     .out: a writable FD, becomes child's stdout/stderr
  31         *     .err > 0 not supported
  32         *   The specified FD is closed by start_command(), even in case
  33         *   of errors!
  34         */
  35        int in;
  36        int out;
  37        int err;
  38        const char *dir;
  39        const char *const *env;
  40        unsigned no_stdin:1;
  41        unsigned no_stdout:1;
  42        unsigned no_stderr:1;
  43        unsigned git_cmd:1; /* if this is to be git sub-command */
  44        unsigned stdout_to_stderr:1;
  45};
  46
  47int start_command(struct child_process *);
  48int finish_command(struct child_process *);
  49int run_command(struct child_process *);
  50
  51#define RUN_COMMAND_NO_STDIN 1
  52#define RUN_GIT_CMD          2  /*If this is to be git sub-command */
  53#define RUN_COMMAND_STDOUT_TO_STDERR 4
  54int run_command_v_opt(const char **argv, int opt);
  55int run_command_v_opt_cd(const char **argv, int opt, const char *dir);
  56
  57/*
  58 * env (the environment) is to be formatted like environ: "VAR=VALUE".
  59 * To unset an environment variable use just "VAR".
  60 */
  61int run_command_v_opt_cd_env(const char **argv, int opt, const char *dir, const char *const *env);
  62
  63/*
  64 * The purpose of the following functions is to feed a pipe by running
  65 * a function asynchronously and providing output that the caller reads.
  66 *
  67 * It is expected that no synchronization and mutual exclusion between
  68 * the caller and the feed function is necessary so that the function
  69 * can run in a thread without interfering with the caller.
  70 */
  71struct async {
  72        /*
  73         * proc writes to fd and closes it;
  74         * returns 0 on success, non-zero on failure
  75         */
  76        int (*proc)(int fd, void *data);
  77        void *data;
  78        int out;        /* caller reads from here and closes it */
  79        pid_t pid;
  80};
  81
  82int start_async(struct async *async);
  83int finish_async(struct async *async);
  84
  85#endif