1 files changed, 235 insertions, 0 deletions
diff --git a/run-command.h b/run-command.h
new file mode 100644
index 000000000000..f769e03f018f
--- /dev/null
+++ b/run-command.h
@@ -0,0 +1,235 @@
+#ifndef RUN_COMMAND_H
+#define RUN_COMMAND_H
+
+#include "thread-utils.h"
+
+#include "argv-array.h"
+
+struct child_process {
+	const char **argv;
+	struct argv_array args;
+	struct argv_array env_array;
+	pid_t pid;
+
+	int trace2_child_id;
+	uint64_t trace2_child_us_start;
+	const char *trace2_child_class;
+	const char *trace2_hook_name;
+
+	/*
+	 * 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: a writable FD, becomes child's stderr
+	 *   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 no_stdin:1;
+	unsigned no_stdout:1;
+	unsigned no_stderr:1;
+	unsigned git_cmd:1; /* if this is to be git sub-command */
+	unsigned silent_exec_failure:1;
+	unsigned stdout_to_stderr:1;
+	unsigned use_shell:1;
+	unsigned clean_on_exit:1;
+	unsigned wait_after_clean:1;
+	void (*clean_on_exit_handler)(struct child_process *process);
+	void *clean_on_exit_handler_cbdata;
+};
+
+#define CHILD_PROCESS_INIT { NULL, ARGV_ARRAY_INIT, ARGV_ARRAY_INIT }
+void child_process_init(struct child_process *);
+void child_process_clear(struct child_process *);
+int is_executable(const char *name);
+
+int start_command(struct child_process *);
+int finish_command(struct child_process *);
+int finish_command_in_signal(struct child_process *);
+int run_command(struct child_process *);
+
+/*
+ * Returns the path to the hook file, or NULL if the hook is missing
+ * or disabled. Note that this points to static storage that will be
+ * overwritten by further calls to find_hook and run_hook_*.
+ */
+const char *find_hook(const char *name);
+LAST_ARG_MUST_BE_NULL
+int run_hook_le(const char *const *env, const char *name, ...);
+int run_hook_ve(const char *const *env, const char *name, va_list args);
+
+#define RUN_COMMAND_NO_STDIN 1
+#define RUN_GIT_CMD	     2	/*If this is to be git sub-command */
+#define RUN_COMMAND_STDOUT_TO_STDERR 4
+#define RUN_SILENT_EXEC_FAILURE 8
+#define RUN_USING_SHELL 16
+#define RUN_CLEAN_ON_EXIT 32
+int run_command_v_opt(const char **argv, int opt);
+int run_command_v_opt_tr2(const char **argv, int opt, const char *tr2_class);
+/*
+ * env (the environment) is to be formatted like environ: "VAR=VALUE".
+ * To unset an environment variable use just "VAR".
+ */
+int run_command_v_opt_cd_env(const char **argv, int opt, const char *dir, const char *const *env);
+int run_command_v_opt_cd_env_tr2(const char **argv, int opt, const char *dir,
+				 const char *const *env, const char *tr2_class);
+
+/**
+ * Execute the given command, sending "in" to its stdin, and capturing its
+ * stdout and stderr in the "out" and "err" strbufs. Any of the three may
+ * be NULL to skip processing.
+ *
+ * Returns -1 if starting the command fails or reading fails, and otherwise
+ * returns the exit code of the command. Any output collected in the
+ * buffers is kept even if the command returns a non-zero exit. The hint fields
+ * gives starting sizes for the strbuf allocations.
+ *
+ * The fields of "cmd" should be set up as they would for a normal run_command
+ * invocation. But note that there is no need to set the in, out, or err
+ * fields; pipe_command handles that automatically.
+ */
+int pipe_command(struct child_process *cmd,
+		 const char *in, size_t in_len,
+		 struct strbuf *out, size_t out_hint,
+		 struct strbuf *err, size_t err_hint);
+
+/**
+ * Convenience wrapper around pipe_command for the common case
+ * of capturing only stdout.
+ */
+static inline int capture_command(struct child_process *cmd,
+				  struct strbuf *out,
+				  size_t hint)
+{
+	return pipe_command(cmd, NULL, 0, out, hint, NULL, 0);
+}
+
+/*
+ * 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 reads from in; closes it before return
+	 * proc writes to out; closes it before return
+	 * returns 0 on success, non-zero on failure
+	 */
+	int (*proc)(int in, int out, void *data);
+	void *data;
+	int in;		/* caller writes here and closes it */
+	int out;	/* caller reads from here and closes it */
+#ifdef NO_PTHREADS
+	pid_t pid;
+#else
+	pthread_t tid;
+	int proc_in;
+	int proc_out;
+#endif
+	int isolate_sigpipe;
+};
+
+int start_async(struct async *async);
+int finish_async(struct async *async);
+int in_async(void);
+int async_with_fork(void);
+void check_pipe(int err);
+
+/**
+ * This callback should initialize the child process and preload the
+ * error channel if desired. The preloading of is useful if you want to
+ * have a message printed directly before the output of the child process.
+ * pp_cb is the callback cookie as passed to run_processes_parallel.
+ * You can store a child process specific callback cookie in pp_task_cb.
+ *
+ * Even after returning 0 to indicate that there are no more processes,
+ * this function will be called again until there are no more running
+ * child processes.
+ *
+ * Return 1 if the next child is ready to run.
+ * Return 0 if there are currently no more tasks to be processed.
+ * To send a signal to other child processes for abortion,
+ * return the negative signal number.
+ */
+typedef int (*get_next_task_fn)(struct child_process *cp,
+				struct strbuf *out,
+				void *pp_cb,
+				void **pp_task_cb);
+
+/**
+ * This callback is called whenever there are problems starting
+ * a new process.
+ *
+ * You must not write to stdout or stderr in this function. Add your
+ * message to the strbuf out instead, which will be printed without
+ * messing up the output of the other parallel processes.
+ *
+ * pp_cb is the callback cookie as passed into run_processes_parallel,
+ * pp_task_cb is the callback cookie as passed into get_next_task_fn.
+ *
+ * Return 0 to continue the parallel processing. To abort return non zero.
+ * To send a signal to other child processes for abortion, return
+ * the negative signal number.
+ */
+typedef int (*start_failure_fn)(struct strbuf *out,
+				void *pp_cb,
+				void *pp_task_cb);
+
+/**
+ * This callback is called on every child process that finished processing.
+ *
+ * You must not write to stdout or stderr in this function. Add your
+ * message to the strbuf out instead, which will be printed without
+ * messing up the output of the other parallel processes.
+ *
+ * pp_cb is the callback cookie as passed into run_processes_parallel,
+ * pp_task_cb is the callback cookie as passed into get_next_task_fn.
+ *
+ * Return 0 to continue the parallel processing.  To abort return non zero.
+ * To send a signal to other child processes for abortion, return
+ * the negative signal number.
+ */
+typedef int (*task_finished_fn)(int result,
+				struct strbuf *out,
+				void *pp_cb,
+				void *pp_task_cb);
+
+/**
+ * Runs up to n processes at the same time. Whenever a process can be
+ * started, the callback get_next_task_fn is called to obtain the data
+ * required to start another child process.
+ *
+ * The children started via this function run in parallel. Their output
+ * (both stdout and stderr) is routed to stderr in a manner that output
+ * from different tasks does not interleave.
+ *
+ * start_failure_fn and task_finished_fn can be NULL to omit any
+ * special handling.
+ */
+int run_processes_parallel(int n,
+			   get_next_task_fn,
+			   start_failure_fn,
+			   task_finished_fn,
+			   void *pp_cb);
+int run_processes_parallel_tr2(int n, get_next_task_fn, start_failure_fn,
+			       task_finished_fn, void *pp_cb,
+			       const char *tr2_category, const char *tr2_label);
+
+#endif