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([2a0a:ef40:600:8501:575d:f6b:be83:bc74]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-3680dab3c38sm6558699f8f.8.2024.07.15.07.13.15 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 15 Jul 2024 07:13:15 -0700 (PDT) Message-ID: <384f0147-d611-493b-a3d4-d83c65bd1114@gmail.com> Date: Mon, 15 Jul 2024 15:13:09 +0100 Precedence: bulk X-Mailing-List: git@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Reply-To: phillip.wood@dunelm.org.uk Subject: Re: [PATCH v3 3/4] pager: introduce wait_for_pager To: =?UTF-8?Q?Rub=C3=A9n_Justo?= , Git List Cc: Junio C Hamano , Dragan Simic , Jeff King , Phillip Wood References: <2653fb37-c8a8-49b1-a804-4be6654a2cad@gmail.com> From: Phillip Wood Content-Language: en-US In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Hi Rubén On 14/07/2024 17:04, Rubén Justo wrote: > Since f67b45f862 (Introduce trivial new pager.c helper infrastructure, > 2006-02-28) we have the machinery to send our output to a pager. > > That machinery, once set up, does not allow us to regain the original > stdio streams. > > In the interactive commands (i.e.: add -p) we want to use the pager for > some output, while maintaining the interaction with the user. > > Modify the pager machinery so that we can use setup_pager and, once > we've finished sending the desired output for the pager, wait for the > pager termination using a new function wait_for_pager. Make this > function reset the pager machinery before returning. Do you have any comments on my thoughts in <8434fafe-f545-49bc-8cc1-d4e8fb634bec@gmail.com> ? Best Wishes Phillip > Signed-off-by: Rubén Justo > --- > pager.c | 43 +++++++++++++++++++++++++++++++++++++------ > pager.h | 1 + > 2 files changed, 38 insertions(+), 6 deletions(-) > > diff --git a/pager.c b/pager.c > index 251adfc2ad..bea4345f6f 100644 > --- a/pager.c > +++ b/pager.c > @@ -14,7 +14,7 @@ int pager_use_color = 1; > > static struct child_process pager_process; > static char *pager_program; > -static int close_fd2; > +static int old_fd1 = -1, old_fd2 = -1; > > /* Is the value coming back from term_columns() just a guess? */ > static int term_columns_guessed; > @@ -24,11 +24,11 @@ static void close_pager_fds(void) > { > /* signal EOF to pager */ > close(1); > - if (close_fd2) > + if (old_fd2 != -1) > close(2); > } > > -static void wait_for_pager_atexit(void) > +static void finish_pager(void) > { > fflush(stdout); > fflush(stderr); > @@ -36,8 +36,34 @@ static void wait_for_pager_atexit(void) > finish_command(&pager_process); > } > > +static void wait_for_pager_atexit(void) > +{ > + if (old_fd1 == -1) > + return; > + > + finish_pager(); > +} > + > +void wait_for_pager(void) > +{ > + finish_pager(); > + sigchain_pop_common(); > + unsetenv("GIT_PAGER_IN_USE"); > + dup2(old_fd1, 1); > + close(old_fd1); > + old_fd1 = -1; > + if (old_fd2 != -1) { > + dup2(old_fd2, 2); > + close(old_fd2); > + old_fd2 = -1; > + } > +} > + > static void wait_for_pager_signal(int signo) > { > + if (old_fd1 == -1) > + return; > + > close_pager_fds(); > finish_command_in_signal(&pager_process); > sigchain_pop(signo); > @@ -113,6 +139,7 @@ void prepare_pager_args(struct child_process *pager_process, const char *pager) > > void setup_pager(void) > { > + static int once = 0; > const char *pager = git_pager(isatty(1)); > > if (!pager) > @@ -142,16 +169,20 @@ void setup_pager(void) > die("unable to execute pager '%s'", pager); > > /* original process continues, but writes to the pipe */ > + old_fd1 = dup(1); > dup2(pager_process.in, 1); > if (isatty(2)) { > - close_fd2 = 1; > + old_fd2 = dup(2); > dup2(pager_process.in, 2); > } > close(pager_process.in); > > - /* this makes sure that the parent terminates after the pager */ > sigchain_push_common(wait_for_pager_signal); > - atexit(wait_for_pager_atexit); > + > + if (!once) { > + once++; > + atexit(wait_for_pager_atexit); > + } > } > > int pager_in_use(void) > diff --git a/pager.h b/pager.h > index b77433026d..103ecac476 100644 > --- a/pager.h > +++ b/pager.h > @@ -5,6 +5,7 @@ struct child_process; > > const char *git_pager(int stdout_is_tty); > void setup_pager(void); > +void wait_for_pager(void); > int pager_in_use(void); > int term_columns(void); > void term_clear_line(void);