win32: UTF8 input: avoid timeout when delivering UTF8 bytes

When windows_read_key - which is the sole consumer of
readConsoleInput_utf8 - is called with a timeout value, it uses
WaitForSingleObject to test whether the console has pending input.

Previously, readConsoleInput_utf8 consumed the input record before
it delivered the UTF8 bytes which are generated from it.

It's not an issue with ASCII-7 input - because indeed there are no
buffered bytes once it's delivered, and, except for console bugs
(when only key-up record exists) also not an issue with 2 or 3 bytes
UTF8 codepoints - because these are generated from a single wchar_t
input record on key-down, and the key-up event is not yet dequeued
while delivering the key-down UTF8 bytes.

But with a surrogate pair, which consumes two wchar_t records to
realize the UTF8 sequence, we previously consumed the records
up to and including the key-up event of the 2nd surrogate half.

This could result in a timeout if there are no further records at
the queue - eventhough some UTF8 bytes are still buffered/pending.

Such timeout can result in the shell aborting - windows_read_key
returns -1, which is later interpreted as EOF of the shell input,
and quits the shell.

Now readConsoleInput_utf8 dequeues an input record only once the
last byte which was generated from this record is delivered,
which we do using PeekConsoleInputW instead of ReadConsoleInputW.

This avoid a timeout as long as there are input bytes to deliver.

0 files changed, 0 insertions, 0 deletions