diff options
| -rw-r--r-- | gdb/event-top.c | 13 | ||||
| -rw-r--r-- | gdb/top.c | 39 |
2 files changed, 39 insertions, 13 deletions
diff --git a/gdb/event-top.c b/gdb/event-top.c index 3566431..74960c8 100644 --- a/gdb/event-top.c +++ b/gdb/event-top.c @@ -863,19 +863,6 @@ gdb_readline_no_editing_callback (gdb_client_data client_data) FILE *stream = ui->instream != nullptr ? ui->instream : ui->stdin_stream; gdb_assert (stream != nullptr); - /* Unbuffer the input stream, so that, later on, the calls to fgetc - fetch only one char at the time from the stream. The fgetc's will - get up to the first newline, but there may be more chars in the - stream after '\n'. If we buffer the input and fgetc drains the - stream, getting stuff beyond the newline as well, a select, done - afterwards will not trigger. - - This unbuffering was, at one point, not applied if the input stream - was a tty, however, the buffering can cause problems, even for a tty, - in some cases. Please ensure that any changes in this area run the MI - tests with the FORCE_SEPARATE_MI_TTY=1 flag being passed. */ - setbuf (stream, NULL); - /* We still need the while loop here, even though it would seem obvious to invoke gdb_readline_no_editing_callback at every character entered. If not using the readline library, the @@ -257,6 +257,41 @@ void (*deprecated_context_hook) (int id); /* The highest UI number ever assigned. */ static int highest_ui_num; +/* Unbuffer STREAM. This is a wrapper around setbuf(STREAM, nullptr) + which applies some special rules for MS-Windows hosts. */ + +static void +unbuffer_stream (FILE *stream) +{ + /* Unbuffer the input stream so that in gdb_readline_no_editing_callback, + the calls to fgetc fetch only one char at the time from STREAM. + + This is important because gdb_readline_no_editing_callback will read + from STREAM up to the first '\n' character, after this GDB returns to + the event loop and relies on a select on STREAM indicating that more + input is pending. + + If STREAM is buffered then the fgetc calls may have moved all the + pending input from the kernel into a local buffer, after which the + select will not indicate that more input is pending, and input after + the first '\n' will not be processed immediately. + + Please ensure that any changes in this area run the MI tests with the + FORCE_SEPARATE_MI_TTY=1 flag being passed. */ + +#ifdef __MINGW32__ + /* With MS-Windows runtime, making stdin unbuffered when it's + connected to the terminal causes it to misbehave. */ + if (!ISATTY (stream)) + setbuf (stream, nullptr); +#else + /* On GNU/Linux the issues described above can impact GDB even when + dealing with input from a terminal. For now we unbuffer the input + stream for everyone except MS-Windows. */ + setbuf (stream, nullptr); +#endif +} + /* See top.h. */ ui::ui (FILE *instream_, FILE *outstream_, FILE *errstream_) @@ -283,6 +318,8 @@ ui::ui (FILE *instream_, FILE *outstream_, FILE *errstream_) { buffer_init (&line_buffer); + unbuffer_stream (instream_); + if (ui_list == NULL) ui_list = this; else @@ -412,6 +449,8 @@ read_command_file (FILE *stream) { struct ui *ui = current_ui; + unbuffer_stream (stream); + scoped_restore save_instream = make_scoped_restore (&ui->instream, stream); |