skywind3000 wrote： > The callback of "out_cb" is convenience to use, but has performance issue: > Gui gets freezed if the background job continues outputing massive data (eg, > grep a high frequency word "to" on the documents root, or some crazy stl > errors). > > Vim is busy in receiving the data and invoking "out_cb" which cause gui no > responsed for a very noticeable period. > > The practice way to prevent gui freeze is introducing a flow control for > background process by reading the fixed number of lines from the channel on a > timer (eg, read 50 lines from stdout each 100ms interval). > > If the grep output is faster then the reader in the timer, system pipe will > be full and "invoking write()" will block the child process until the system > pipe buffer has free space again (some data have been readed out by vim). > > In order to process the job output more smoothly, I tried to use this > approach but when I am ready to read data from the channel in a timer, It is > confused that both "\n" (empty line) and "not enough data" return "" from > ch_read(). > > If I want to read out at most 100 lines from a channel in an interval, how > can I tell if there is no data at the moment or it's just a "\n" from child > process ? > > No clue to decide whether to continue reading or just break out. > > When I am using "(pipe object).readline()" from python's subprocess module, > "abc\n" means a line "abc", "\n" means an empty line and "" means not enough > data. It's very simple without any ambiguity. > > But when I am using "ch_read()" in vim. "abc" means a line "abc", and both > (empty line) and (no message) return "". > > Is it a "logic fallacy" of "ch_read()" ??
btw, the "ch_read()" referenced before is invoked with "timeout=0" in "NL" mode. -- -- You received this message from the "vim_dev" maillist. Do not top-post! Type your reply below the text you are replying to. For more information, visit http://www.vim.org/maillist.php --- You received this message because you are subscribed to the Google Groups "vim_dev" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. For more options, visit https://groups.google.com/d/optout.
