From: "Johannes Schindelin via GitGitGadget" <gitgitgadget@gmail.com> To: git@vger.kernel.org Cc: Johannes Schindelin <johannes.schindelin@gmx.de>, Johannes Schindelin <johannes.schindelin@gmx.de> Subject: [PATCH v4 08/10] built-in add -p: handle Escape sequences in interactive.singlekey mode Date: Tue, 14 Jan 2020 18:43:51 +0000 [thread overview] Message-ID: <cdc609f8fa349b9ffada68dfd6fd183365222ba7.1579027433.git.gitgitgadget@gmail.com> (raw) In-Reply-To: <pull.175.v4.git.1579027433.gitgitgadget@gmail.com> From: Johannes Schindelin <johannes.schindelin@gmx.de> This recapitulates part of b5cc003253c8 (add -i: ignore terminal escape sequences, 2011-05-17): add -i: ignore terminal escape sequences On the author's terminal, the up-arrow input sequence is ^[[A, and thus fat-fingering an up-arrow into 'git checkout -p' is quite dangerous: git-add--interactive.perl will ignore the ^[ and [ characters and happily treat A as "discard everything". As a band-aid fix, use Term::Cap to get all terminal capabilities. Then use the heuristic that any capability value that starts with ^[ (i.e., \e in perl) must be a key input sequence. Finally, given an input that starts with ^[, read more characters until we have read a full escape sequence, then return that to the caller. We use a timeout of 0.5 seconds on the subsequent reads to avoid getting stuck if the user actually input a lone ^[. Since none of the currently recognized keys start with ^[, the net result is that the sequence as a whole will be ignored and the help displayed. Note that we leave part for later which uses "Term::Cap to get all terminal capabilities", for several reasons: 1. it is actually not really necessary, as the timeout of 0.5 seconds should be plenty sufficient to catch Escape sequences, 2. it is cleaner to keep the change to special-case Escape sequences separate from the change that reads all terminal capabilities to speed things up, and 3. in practice, relying on the terminal capabilities is a bit overrated, as the information could be incomplete, or plain wrong. For example, in this developer's tmux sessions, the terminal capabilities claim that the "cursor up" sequence is ^[M, but the actual sequence produced by the "cursor up" key is ^[[A. Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de> --- compat/terminal.c | 56 ++++++++++++++++++++++++++++++++++++++++++++++- 1 file changed, 55 insertions(+), 1 deletion(-) diff --git a/compat/terminal.c b/compat/terminal.c index 1b2564042a..b7f58d1781 100644 --- a/compat/terminal.c +++ b/compat/terminal.c @@ -161,6 +161,37 @@ static int enable_non_canonical(void) return disable_bits(ENABLE_ECHO_INPUT | ENABLE_LINE_INPUT | ENABLE_PROCESSED_INPUT); } +/* + * Override `getchar()`, as the default implementation does not use + * `ReadFile()`. + * + * This poses a problem when we want to see whether the standard + * input has more characters, as the default of Git for Windows is to start the + * Bash in a MinTTY, which uses a named pipe to emulate a pty, in which case + * our `poll()` emulation calls `PeekNamedPipe()`, which seems to require + * `ReadFile()` to be called first to work properly (it only reports 0 + * available bytes, otherwise). + * + * So let's just override `getchar()` with a version backed by `ReadFile()` and + * go our merry ways from here. + */ +static int mingw_getchar(void) +{ + DWORD read = 0; + unsigned char ch; + + if (!ReadFile(GetStdHandle(STD_INPUT_HANDLE), &ch, 1, &read, NULL)) + return EOF; + + if (!read) { + error("Unexpected 0 read"); + return EOF; + } + + return ch; +} +#define getchar mingw_getchar + #endif #ifndef FORCE_TEXT @@ -228,8 +259,31 @@ int read_key_without_echo(struct strbuf *buf) restore_term(); return EOF; } - strbuf_addch(buf, ch); + + if (ch == '\033' /* ESC */) { + /* + * We are most likely looking at an Escape sequence. Let's try + * to read more bytes, waiting at most half a second, assuming + * that the sequence is complete if we did not receive any byte + * within that time. + * + * Start by replacing the Escape byte with ^[ */ + strbuf_splice(buf, buf->len - 1, 1, "^[", 2); + + for (;;) { + struct pollfd pfd = { .fd = 0, .events = POLLIN }; + + if (poll(&pfd, 1, 500) < 1) + break; + + ch = getchar(); + if (ch == EOF) + return 0; + strbuf_addch(buf, ch); + } + } + restore_term(); return 0; } -- gitgitgadget
next prev parent reply other threads:[~2020-01-14 18:44 UTC|newest] Thread overview: 63+ messages / expand[flat|nested] mbox.gz Atom feed top 2019-12-21 22:41 [PATCH 0/9] built-in add -p: add support for the same config settings as the Perl version Johannes Schindelin via GitGitGadget 2019-12-21 22:41 ` [PATCH 1/9] built-in add -p: support interactive.diffFilter Johannes Schindelin via GitGitGadget 2019-12-21 22:41 ` [PATCH 2/9] built-in add -p: handle diff.algorithm Johannes Schindelin via GitGitGadget 2019-12-21 22:41 ` [PATCH 3/9] terminal: make the code of disable_echo() reusable Johannes Schindelin via GitGitGadget 2019-12-21 22:41 ` [PATCH 4/9] terminal: accommodate Git for Windows' default terminal Johannes Schindelin via GitGitGadget 2019-12-21 22:41 ` [PATCH 5/9] terminal: add a new function to read a single keystroke Johannes Schindelin via GitGitGadget 2019-12-21 22:41 ` [PATCH 6/9] built-in add -p: respect the `interactive.singlekey` config setting Johannes Schindelin via GitGitGadget 2019-12-21 22:41 ` [PATCH 7/9] built-in add -p: handle Escape sequences in interactive.singlekey mode Johannes Schindelin via GitGitGadget 2019-12-21 22:41 ` [PATCH 8/9] built-in add -p: handle Escape sequences more efficiently Johannes Schindelin via GitGitGadget 2019-12-21 22:42 ` [PATCH 9/9] ci: include the built-in `git add -i` in the `linux-gcc` job Johannes Schindelin via GitGitGadget 2019-12-21 22:53 ` SZEDER Gábor 2019-12-25 11:56 ` Johannes Schindelin 2019-12-22 0:11 ` Junio C Hamano 2019-12-25 11:57 ` Johannes Schindelin 2019-12-24 18:23 ` [PATCH 0/9] built-in add -p: add support for the same config settings as the Perl version Junio C Hamano 2019-12-24 18:39 ` Junio C Hamano 2019-12-25 8:46 ` Simon Ruderich 2019-12-25 12:09 ` Johannes Schindelin 2019-12-25 12:02 ` Johannes Schindelin 2019-12-25 11:56 ` [PATCH v2 " Johannes Schindelin via GitGitGadget 2019-12-25 11:56 ` [PATCH v2 1/9] built-in add -p: support interactive.diffFilter Johannes Schindelin via GitGitGadget 2020-01-07 22:57 ` SZEDER Gábor 2020-01-13 6:47 ` Johannes Schindelin 2019-12-25 11:56 ` [PATCH v2 2/9] built-in add -p: handle diff.algorithm Johannes Schindelin via GitGitGadget 2019-12-25 11:56 ` [PATCH v2 3/9] terminal: make the code of disable_echo() reusable Johannes Schindelin via GitGitGadget 2019-12-25 11:56 ` [PATCH v2 4/9] terminal: accommodate Git for Windows' default terminal Johannes Schindelin via GitGitGadget 2019-12-25 11:56 ` [PATCH v2 5/9] terminal: add a new function to read a single keystroke Johannes Schindelin via GitGitGadget 2019-12-25 11:56 ` [PATCH v2 6/9] built-in add -p: respect the `interactive.singlekey` config setting Johannes Schindelin via GitGitGadget 2019-12-25 11:56 ` [PATCH v2 7/9] built-in add -p: handle Escape sequences in interactive.singlekey mode Johannes Schindelin via GitGitGadget 2019-12-25 11:56 ` [PATCH v2 8/9] built-in add -p: handle Escape sequences more efficiently Johannes Schindelin via GitGitGadget 2019-12-25 11:57 ` [PATCH v2 9/9] ci: include the built-in `git add -i` in the `linux-gcc` job Johannes Schindelin via GitGitGadget 2019-12-26 20:48 ` Derrick Stolee 2020-01-01 22:10 ` Johannes Schindelin 2019-12-26 20:45 ` [PATCH v2 0/9] built-in add -p: add support for the same config settings as the Perl version Junio C Hamano 2020-01-13 8:29 ` [PATCH v3 00/10] " Johannes Schindelin via GitGitGadget 2020-01-13 8:29 ` [PATCH v3 01/10] built-in add -i/-p: treat SIGPIPE as EOF Johannes Schindelin via GitGitGadget 2020-01-13 17:04 ` SZEDER Gábor 2020-01-13 18:33 ` Jeff King 2020-01-15 18:32 ` Junio C Hamano 2020-01-15 19:03 ` Jeff King 2020-01-14 12:47 ` Johannes Schindelin 2020-01-17 14:32 ` SZEDER Gábor 2020-01-17 18:58 ` Jeff King 2020-01-13 8:29 ` [PATCH v3 02/10] built-in add -p: support interactive.diffFilter Johannes Schindelin via GitGitGadget 2020-01-13 8:29 ` [PATCH v3 03/10] built-in add -p: handle diff.algorithm Johannes Schindelin via GitGitGadget 2020-01-13 8:29 ` [PATCH v3 04/10] terminal: make the code of disable_echo() reusable Johannes Schindelin via GitGitGadget 2020-01-13 8:29 ` [PATCH v3 05/10] terminal: accommodate Git for Windows' default terminal Johannes Schindelin via GitGitGadget 2020-01-13 8:29 ` [PATCH v3 06/10] terminal: add a new function to read a single keystroke Johannes Schindelin via GitGitGadget 2020-01-13 8:29 ` [PATCH v3 07/10] built-in add -p: respect the `interactive.singlekey` config setting Johannes Schindelin via GitGitGadget 2020-01-13 8:29 ` [PATCH v3 08/10] built-in add -p: handle Escape sequences in interactive.singlekey mode Johannes Schindelin via GitGitGadget 2020-01-13 8:29 ` [PATCH v3 09/10] built-in add -p: handle Escape sequences more efficiently Johannes Schindelin via GitGitGadget 2020-01-13 8:29 ` [PATCH v3 10/10] ci: include the built-in `git add -i` in the `linux-gcc` job Johannes Schindelin via GitGitGadget 2020-01-14 18:43 ` [PATCH v4 00/10] built-in add -p: add support for the same config settings as the Perl version Johannes Schindelin via GitGitGadget 2020-01-14 18:43 ` [PATCH v4 01/10] t3701: adjust difffilter test Johannes Schindelin via GitGitGadget 2020-01-14 18:43 ` [PATCH v4 02/10] built-in add -p: support interactive.diffFilter Johannes Schindelin via GitGitGadget 2020-01-14 18:43 ` [PATCH v4 03/10] built-in add -p: handle diff.algorithm Johannes Schindelin via GitGitGadget 2020-01-14 18:43 ` [PATCH v4 04/10] terminal: make the code of disable_echo() reusable Johannes Schindelin via GitGitGadget 2020-01-14 18:43 ` [PATCH v4 05/10] terminal: accommodate Git for Windows' default terminal Johannes Schindelin via GitGitGadget 2020-01-14 18:43 ` [PATCH v4 06/10] terminal: add a new function to read a single keystroke Johannes Schindelin via GitGitGadget 2020-01-14 18:43 ` [PATCH v4 07/10] built-in add -p: respect the `interactive.singlekey` config setting Johannes Schindelin via GitGitGadget 2020-01-14 18:43 ` Johannes Schindelin via GitGitGadget [this message] 2020-01-14 18:43 ` [PATCH v4 09/10] built-in add -p: handle Escape sequences more efficiently Johannes Schindelin via GitGitGadget 2020-01-14 18:43 ` [PATCH v4 10/10] ci: include the built-in `git add -i` in the `linux-gcc` job Johannes Schindelin via GitGitGadget
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