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v/vlib/os/process.v
2021-02-07 05:19:05 +01:00

245 lines
6.1 KiB
V

module os
// ProcessState.not_started - the process has not yet started
// ProcessState.running - the process is currently running
// ProcessState.stopped - the process was running, but was stopped temporarily
// ProcessState.exited - the process has finished/exited
// ProcessState.aborted - the process was terminated by a signal
pub enum ProcessState {
not_started
running
stopped
exited
aborted
}
[ref_only]
pub struct Process {
pub:
filename string // the process's command file path
pub mut:
pid int // the PID of the process
code int = -1
// the exit code of the process, != -1 *only* when status is .exited *and* the process was not aborted
status ProcessState = .not_started
// the current status of the process
err string // if the process fails, contains the reason why
args []string // the arguments that the command takes
env_is_custom bool // true, when the environment was customized with .set_environment
env []string // the environment with which the process was started (list of 'var=val')
use_stdio_ctl bool // when true, then you can use p.stdin_write(), p.stdout_slurp() and p.stderr_slurp()
stdio_fd [3]int // the file descriptors
}
// new_process - create a new process descriptor
// NB: new does NOT start the new process.
// That is done because you may want to customize it first,
// by calling different set_ methods on it.
// In order to start it, call p.run() or p.wait()
pub fn new_process(filename string) &Process {
return &Process{
filename: filename
}
}
// set_args - set the arguments for the new process
pub fn (mut p Process) set_args(pargs []string) &Process {
if p.status != .not_started {
return p
}
p.args = pargs
return p
}
// set_environment - set a custom environment variable mapping for the new process
pub fn (mut p Process) set_environment(envs map[string]string) &Process {
if p.status != .not_started {
return p
}
p.env_is_custom = true
p.env = []string{}
for k, v in envs {
p.env << '$k=$v'
}
return p
}
// run - starts the new process
pub fn (mut p Process) run() &Process {
if p.status != .not_started {
return p
}
p._spawn()
return p
}
// signal_kill - kills the process, after that it is no longer running
pub fn (mut p Process) signal_kill() &Process {
if p.status !in [.running, .stopped] {
return p
}
p._signal_kill()
p.status = .aborted
return p
}
// signal_stop - stops the process, you can resume it with p.signal_continue()
pub fn (mut p Process) signal_stop() &Process {
if p.status != .running {
return p
}
p._signal_stop()
p.status = .stopped
return p
}
// signal_continue - tell a stopped process to continue/resume its work
pub fn (mut p Process) signal_continue() &Process {
if p.status != .stopped {
return p
}
p._signal_continue()
p.status = .running
return p
}
// wait - wait for a process to finish.
// NB: You have to call p.wait(), otherwise a finished process
// would get to a zombie state, and its resources will not get
// released fully, until its parent process exits.
// NB: This call will block the calling process until the child
// process is finished.
pub fn (mut p Process) wait() &Process {
if p.status == .not_started {
p._spawn()
}
if p.status !in [.running, .stopped] {
return p
}
p._wait()
return p
}
//
// _spawn - should not be called directly, but only by p.run()/p.wait() .
// It encapsulates the fork/execve mechanism that allows the
// asynchronous starting of the new child process.
fn (mut p Process) _spawn() int {
if !p.env_is_custom {
p.env = []string{}
current_environment := environ()
for k, v in current_environment {
p.env << '$k=$v'
}
}
mut pid := 0
$if windows {
pid = p.win_spawn_process()
} $else {
pid = p.unix_spawn_process()
}
p.pid = pid
p.status = .running
return 0
}
// is_alive - query whether the process p.pid is still alive
pub fn (mut p Process) is_alive() bool {
if p.status in [.running, .stopped] {
return p._is_alive()
}
return false
}
//
pub fn (mut p Process) set_redirect_stdio() &Process {
p.use_stdio_ctl = true
return p
}
pub fn (mut p Process) stdin_write(s string) {
p._check_redirection_call('stdin_write')
fd_write(p.stdio_fd[0], s)
}
// will read from stdout pipe, will only return when EOF (end of file) or data
// means this will block unless there is data
pub fn (mut p Process) stdout_slurp() string {
p._check_redirection_call('stdout_slurp')
return fd_slurp(p.stdio_fd[1]).join('')
}
// read from stderr pipe, wait for data or EOF
pub fn (mut p Process) stderr_slurp() string {
p._check_redirection_call('stderr_slurp')
return fd_slurp(p.stdio_fd[2]).join('')
}
// read from stdout, return if data or not
pub fn (mut p Process) stdout_read() string {
p._check_redirection_call('stdout_read')
s, _ := fd_read(p.stdio_fd[1], 4096)
return s
}
pub fn (mut p Process) stderr_read() string {
p._check_redirection_call('stderr_read')
s, _ := fd_read(p.stdio_fd[2], 4096)
return s
}
// _check_redirection_call - should be called just by stdxxx methods
fn (mut p Process) _check_redirection_call(fn_name string) {
if !p.use_stdio_ctl {
panic('Call p.set_redirect_stdio() before calling p.$fn_name')
}
if p.status == .not_started {
panic('Call p.${fn_name}() after you have called p.run()')
}
}
// _signal_stop - should not be called directly, except by p.signal_stop
fn (mut p Process) _signal_stop() {
$if windows {
p.win_stop_process()
} $else {
p.unix_stop_process()
}
}
// _signal_continue - should not be called directly, just by p.signal_continue
fn (mut p Process) _signal_continue() {
$if windows {
p.win_resume_process()
} $else {
p.unix_resume_process()
}
}
// _signal_kill - should not be called directly, except by p.signal_kill
fn (mut p Process) _signal_kill() {
$if windows {
p.win_kill_process()
} $else {
p.unix_kill_process()
}
}
// _wait - should not be called directly, except by p.wait()
fn (mut p Process) _wait() {
$if windows {
p.win_wait()
} $else {
p.unix_wait()
}
}
// _is_alive - should not be called directly, except by p.is_alive()
fn (mut p Process) _is_alive() bool {
$if windows {
return p.win_is_alive()
} $else {
return p.unix_is_alive()
}
}