This is an archive of the discontinued Mercurial Phabricator instance.

Differential D3577

crecord: fallback to text mode if diffs are too big for curses mode
ClosedPublic

Authored by spectral on May 18 2018, 2:12 AM.

Details

Reviewers
pulkit
Group Reviewers
hg-reviewers
Commits
rHGdabc2237963c: crecord: fallback to text mode if diffs are too big for curses mode
Summary

crecord uses curses.newpad to create a region that we can then scroll around in
by moving the main 'screen' as a veiwport into the (probably larger than the
actual screen) pad. Internally, at least in ncurses, pads are implemented using
windows, which have their dimensions limited to a certain size. Depending on
compilation options for ncurses, this size might be pretty small: (signed)
short, or it might be larger ((signed) int).

crecord wants to have enough room to have all of the contents of the main area
of the chunkselector in the pad; this means that the full size with everything
expanded must be less than these (undocumented, afaict) limits.

It's not easy to write tests for this because the limits are platform- and
installation- dependent and undocumented / unqueryable, as far as I can tell.

Diff Detail

Repository
rHG Mercurial
Lint
Automatic diff as part of commit; lint not applicable.
Unit
Automatic diff as part of commit; unit tests not applicable.

Event Timeline

spectral created this revision.May 18 2018, 2:12 AM
pulkit accepted this revision.May 18 2018, 2:09 PM
Closed by commit rHGdabc2237963c: crecord: fallback to text mode if diffs are too big for curses mode (authored by spectral). · Explain WhyMay 18 2018, 2:24 PM
This revision was automatically updated to reflect the committed changes.

Revision Contents
Changeset List

PathPackages
Mmercurial/cmdutil.py (26 lines)
Mmercurial/crecord.py (14 lines)

Diff 8740

mercurial/cmdutil.py

oldwrite = ui.write oldwrite = ui.write
def wrap(*args, **kwargs): def wrap(*args, **kwargs):
return wrapwrite(oldwrite, *args, **kwargs) return wrapwrite(oldwrite, *args, **kwargs)
setattr(ui, 'write', wrap) setattr(ui, 'write', wrap)
return oldwrite return oldwrite
def filterchunks(ui, originalhunks, usecurses, testfile, operation=None): def filterchunks(ui, originalhunks, usecurses, testfile, operation=None):
try:
if usecurses: if usecurses:
if testfile: if testfile:
recordfn = crecordmod.testdecorator(testfile, recordfn = crecordmod.testdecorator(
crecordmod.testchunkselector) testfile, crecordmod.testchunkselector)
else: else:
recordfn = crecordmod.chunkselector recordfn = crecordmod.chunkselector
return crecordmod.filterpatch(ui, originalhunks, recordfn, operation) return crecordmod.filterpatch(ui, originalhunks, recordfn,
operation)
except crecordmod.fallbackerror as e:
ui.warn('%s\n' % e.message)
ui.warn(_('falling back to text mode\n'))
else:
return patch.filterpatch(ui, originalhunks, operation) return patch.filterpatch(ui, originalhunks, operation)
def recordfilter(ui, originalhunks, operation=None): def recordfilter(ui, originalhunks, operation=None):
""" Prompts the user to filter the originalhunks and return a list of """ Prompts the user to filter the originalhunks and return a list of
selected hunks. selected hunks.
*operation* is used for to build ui messages to indicate the user what *operation* is used for to build ui messages to indicate the user what
kind of filtering they are doing: reverting, committing, shelving, etc. kind of filtering they are doing: reverting, committing, shelving, etc.
(see patch.filterpatch). (see patch.filterpatch).
""" """

mercurial/crecord.py

try: try:
import wcurses as curses import wcurses as curses
curses.error curses.error
except ImportError: except ImportError:
# wcurses is not shipped on Windows by default, or python is not # wcurses is not shipped on Windows by default, or python is not
# compiled with curses # compiled with curses
curses = False curses = False
class fallbackerror(error.Abort):
"""Error that indicates the client should try to fallback to text mode."""
# Inherits from error.Abort so that existing behavior is preserved if the
# calling code does not know how to fallback.
def checkcurses(ui): def checkcurses(ui):
"""Return True if the user wants to use curses """Return True if the user wants to use curses
This method returns True if curses is found (and that python is built with This method returns True if curses is found (and that python is built with
it) and that the user has the correct flag for the ui. it) and that the user has the correct flag for the ui.
""" """
return curses and ui.interface("chunkselector") == "curses" return curses and ui.interface("chunkselector") == "curses"
""" """
ui.write(_('starting interactive selection\n')) ui.write(_('starting interactive selection\n'))
chunkselector = curseschunkselector(headerlist, ui, operation) chunkselector = curseschunkselector(headerlist, ui, operation)
origsigtstp = sentinel = object() origsigtstp = sentinel = object()
if util.safehasattr(signal, 'SIGTSTP'): if util.safehasattr(signal, 'SIGTSTP'):
origsigtstp = signal.getsignal(signal.SIGTSTP) origsigtstp = signal.getsignal(signal.SIGTSTP)
try: try:
curses.wrapper(chunkselector.main) curses.wrapper(chunkselector.main)
if chunkselector.initerr is not None: if chunkselector.initexc is not None:
raise error.Abort(chunkselector.initerr) raise chunkselector.initexc
# ncurses does not restore signal handler for SIGTSTP # ncurses does not restore signal handler for SIGTSTP
finally: finally:
if origsigtstp is not sentinel: if origsigtstp is not sentinel:
signal.signal(signal.SIGTSTP, origsigtstp) signal.signal(signal.SIGTSTP, origsigtstp)
return chunkselector.opts return chunkselector.opts
def testdecorator(testfn, f): def testdecorator(testfn, f):
def u(*args, **kwargs): def u(*args, **kwargs):
finally: finally:
if origsigwinch is not sentinel: if origsigwinch is not sentinel:
signal.signal(signal.SIGWINCH, origsigwinch) signal.signal(signal.SIGWINCH, origsigwinch)
def _main(self, stdscr): def _main(self, stdscr):
self.stdscr = stdscr self.stdscr = stdscr
# error during initialization, cannot be printed in the curses # error during initialization, cannot be printed in the curses
# interface, it should be printed by the calling code # interface, it should be printed by the calling code
self.initerr = None self.initexc = None
self.yscreensize, self.xscreensize = self.stdscr.getmaxyx() self.yscreensize, self.xscreensize = self.stdscr.getmaxyx()
curses.start_color() curses.start_color()
try: try:
curses.use_default_colors() curses.use_default_colors()
except curses.error: except curses.error:
self.usecolor = False self.usecolor = False
self.chunkpad = curses.newpad(1, self.xscreensize) self.chunkpad = curses.newpad(1, self.xscreensize)
# add 1 so to account for last line text reaching end of line # add 1 so to account for last line text reaching end of line
self.numpadlines = self.getnumlinesdisplayed(ignorefolding=True) + 1 self.numpadlines = self.getnumlinesdisplayed(ignorefolding=True) + 1
try: try:
self.chunkpad = curses.newpad(self.numpadlines, self.xscreensize) self.chunkpad = curses.newpad(self.numpadlines, self.xscreensize)
except curses.error: except curses.error:
self.initerr = _('this diff is too large to be displayed') self.initexc = fallbackerror(
_('this diff is too large to be displayed'))
return return
# initialize selecteditemendline (initial start-line is 0) # initialize selecteditemendline (initial start-line is 0)
self.selecteditemendline = self.getnumlinesdisplayed( self.selecteditemendline = self.getnumlinesdisplayed(
self.currentselecteditem, recursechildren=False) self.currentselecteditem, recursechildren=False)
while True: while True:
self.updatescreen() self.updatescreen()
try: try: