comparison hgext/pager.py @ 30876:3a4c0905f357

util: always force line buffered stdout when stdout is a tty (BC)

pager replaced stdout with a line buffered version to work around glibc
deciding on a buffering strategy on the first write to stdout. This is going
to make my next patch hard, as replacing stdout will make tracking time
spent blocked on it more challenging.

Move the line buffering requirement to util.py, and remove it from pager.
This means that the abuse of ui.formatted=True and pager set to cat or equivalent
no longer results in a line-buffered output to a pipe, hence (BC), although
I don't expect anyone to be affected

30875:1791be8a95c5

def _runpager(ui, p):
    pager = subprocess.Popen(p, shell=True, bufsize=-1,
                             close_fds=util.closefds, stdin=subprocess.PIPE,
                             stdout=util.stdout, stderr=util.stderr)

    # back up original file objects and descriptors
    olduifout = ui.fout
    oldstdout = util.stdout
    stdoutfd = os.dup(util.stdout.fileno())
    stderrfd = os.dup(util.stderr.fileno())

    # create new line-buffered stdout so that output can show up immediately
    ui.fout = util.stdout = newstdout = os.fdopen(util.stdout.fileno(), 'wb', 1)
    os.dup2(pager.stdin.fileno(), util.stdout.fileno())
    if ui._isatty(util.stderr):
        os.dup2(pager.stdin.fileno(), util.stderr.fileno())

    @atexit.register
    def killpager():
        if util.safehasattr(signal, "SIGINT"):
            signal.signal(signal.SIGINT, signal.SIG_IGN)
        pager.stdin.close()
        ui.fout = olduifout
        util.stdout = oldstdout
        # close new stdout while it's associated with pager; otherwise stdout
        # fd would be closed when newstdout is deleted
        newstdout.close()
        # restore original fds: stdout is open again
        os.dup2(stdoutfd, util.stdout.fileno())
        os.dup2(stderrfd, util.stderr.fileno())
        pager.wait()

def uisetup(ui):
    class pagerui(ui.__class__):
        def _runpager(self, pagercmd):

30876:3a4c0905f357

def _runpager(ui, p):
    pager = subprocess.Popen(p, shell=True, bufsize=-1,
                             close_fds=util.closefds, stdin=subprocess.PIPE,
                             stdout=util.stdout, stderr=util.stderr)

    # back up original file descriptors
    stdoutfd = os.dup(util.stdout.fileno())
    stderrfd = os.dup(util.stderr.fileno())

    os.dup2(pager.stdin.fileno(), util.stdout.fileno())
    if ui._isatty(util.stderr):
        os.dup2(pager.stdin.fileno(), util.stderr.fileno())

    @atexit.register
    def killpager():
        if util.safehasattr(signal, "SIGINT"):
            signal.signal(signal.SIGINT, signal.SIG_IGN)
        # restore original fds, closing pager.stdin copies in the process
        os.dup2(stdoutfd, util.stdout.fileno())
        os.dup2(stderrfd, util.stderr.fileno())
        pager.stdin.close()
        pager.wait()

def uisetup(ui):
    class pagerui(ui.__class__):
        def _runpager(self, pagercmd):