Merge branch 'maint-1.5.4' into maint

[git.git] / run-command.h

diff --git a/run-command.h b/run-command.h
index 7958eb1e0b7a927019460e06d7a01622eddf81df..debe3074b5a01fb5a19e61f07ff66c250cdc4f82 100644 (file)
--- a/run-command.h
+++ b/run-command.h
@@ -14,14 +14,32 @@ enum {
 struct child_process {
        const char **argv;
        pid_t pid;
+       /*
+        * Using .in, .out, .err:
+        * - Specify 0 for no redirections (child inherits stdin, stdout,
+        *   stderr from parent).
+        * - Specify -1 to have a pipe allocated as follows:
+        *     .in: returns the writable pipe end; parent writes to it,
+        *          the readable pipe end becomes child's stdin
+        *     .out, .err: returns the readable pipe end; parent reads from
+        *          it, the writable pipe end becomes child's stdout/stderr
+        *   The caller of start_command() must close the returned FDs
+        *   after it has completed reading from/writing to it!
+        * - Specify > 0 to set a channel to a particular FD as follows:
+        *     .in: a readable FD, becomes child's stdin
+        *     .out: a writable FD, becomes child's stdout/stderr
+        *     .err > 0 not supported
+        *   The specified FD is closed by start_command(), even in case
+        *   of errors!
+        */
        int in;
        int out;
+       int err;
        const char *dir;
        const char *const *env;
-       unsigned close_in:1;
-       unsigned close_out:1;
        unsigned no_stdin:1;
        unsigned no_stdout:1;
+       unsigned no_stderr:1;
        unsigned git_cmd:1; /* if this is to be git sub-command */
        unsigned stdout_to_stderr:1;
 };
@@ -42,4 +60,26 @@ int run_command_v_opt_cd(const char **argv, int opt, const char *dir);
  */
 int run_command_v_opt_cd_env(const char **argv, int opt, const char *dir, const char *const *env);
 
+/*
+ * The purpose of the following functions is to feed a pipe by running
+ * a function asynchronously and providing output that the caller reads.
+ *
+ * It is expected that no synchronization and mutual exclusion between
+ * the caller and the feed function is necessary so that the function
+ * can run in a thread without interfering with the caller.
+ */
+struct async {
+       /*
+        * proc writes to fd and closes it;
+        * returns 0 on success, non-zero on failure
+        */
+       int (*proc)(int fd, void *data);
+       void *data;
+       int out;        /* caller reads from here and closes it */
+       pid_t pid;
+};
+
+int start_async(struct async *async);
+int finish_async(struct async *async);
+
 #endif