Re: [PATCH v2 0/2] improve interactive-patch

> On Tue, Mar 26, 2024 at 12:13:46PM -0700, Junio C Hamano wrote:
>> > On Tue, Mar 26, 2024 at 08:31:41AM -0700, Junio C Hamano wrote:
>> >
>> >> 'r'edisplay may work well (and I wonder "r | less" or
>> >> piping the hunk display to anything in general would be a useful
>> >> future enhancement).
>> >
>> 
>> It would be more like tweaking fputs() of a strbuf that
>> was filled by render_hunk() to instead spawn a pager and feed the
>> same strbuf to it, or something.  IOW, we already have the payload
>> to show.  We just want a pager involved in its showing so that users
>> with a huge hunk that does not fit on a page can use "less" on it.
> 
> I do not plan to address this in this series, but while the topic is
> warm;  Perhaps?:

> --- >8 ---
> diff --git a/add-patch.c b/add-patch.c
> index 778f168298..cb74fe84f5 100644
> --- a/add-patch.c
> +++ b/add-patch.c
> @@ -5,6 +5,7 @@
>  #include "environment.h"
>  #include "gettext.h"
>  #include "object-name.h"
> +#include "pager.h"
>  #include "read-cache-ll.h"
>  #include "repository.h"
>  #include "strbuf.h"
> @@ -1450,7 +1451,7 @@ static int patch_update_file(struct add_p_state 
> *s,
>  		if (file_diff->hunk_nr) {
>  			if (rendered_hunk_index != hunk_index) {
>  				render_hunk(s, hunk, 0, colored, &s->buf);
> -				fputs(s->buf.buf, stdout);
> +				fputs_to_pager(s->buf.buf);
>  				rendered_hunk_index = hunk_index;
>  			}
> 
> diff --git a/pager.c b/pager.c
> index b8822a9381..f00fc87a67 100644
> --- a/pager.c
> +++ b/pager.c
> @@ -264,3 +264,30 @@ int check_pager_config(const char *cmd)
>  		pager_program = data.value;
>  	return data.want;
>  }
> +
> +void fputs_to_pager(const char* s)
> +{
> +	struct child_process process;
> +	FILE* pager_stdin;
> +	const char *pager = git_pager(isatty(1));
> +
> +	if (!pager) {
> +		fputs(s, stdout);
> +		return;
> +	}
> +
> +	child_process_init(&process);
> +
> +	prepare_pager_args(&pager_process, pager);
> +	pager_process.in = -1;
> +	strvec_push(&pager_process.env, "GIT_PAGER_IN_USE");
> +	if (start_command(&pager_process))
> +		return;
> +
> +	pager_stdin = fdopen(pager_process.in, "w");
> +	fputs(s, pager_stdin);
> +	fflush(pager_stdin);
> +
> +	close(pager_process.in);
> +	finish_command(&pager_process);
> +}
> diff --git a/pager.h b/pager.h
> index b77433026d..dcccfa632b 100644
> --- a/pager.h
> +++ b/pager.h
> @@ -11,6 +11,7 @@ void term_clear_line(void);
>  int decimal_width(uintmax_t);
>  int check_pager_config(const char *cmd);
>  void prepare_pager_args(struct child_process *, const char *pager);
> +void fputs_to_pager(const char* s);
> 
>  extern int pager_use_color;