Ability to serve as generic frecency database

[purevg]

zoxide already have the capability to be a generic frecency database for other purposes. It would be very nice to be able to disable the directory check being done in add.rs file through an environment variable or an option.

I'm already able to use it as a generic frecency list if I use the following wrapper script which disables this check by use of a ld_preload trick.

With this script, I'm able to use it like the following example to have a frecency list for my executables and its working fine:

( frecency test query -l | cut -d/ -f2-; dmenu_path ) | fzf | sed 's,^,/,' | tee /dev/stderr | xargs -r frecency test add

It can be used the same way with all kind of list like emoji insertion history, profile selection history etc. It would just be nicer to not have to use a ld_preload and instead just rely on a environment variable.

The wrapper script:

#!/bin/sh -eu

ensure_ld_preload_lib_present()
{
    local dir="$HOME/.cache/frecency"
    if [ ! -e "$dir/fake_dir.so" ]; then
        mkdir -p "$dir"
        cat > "$dir/fake_dir.c" <<"EOF"
// gcc -shared -fPIC -o fake_dir.so fake_dir.c
#define _GNU_SOURCE
#include <sys/stat.h>

int statx(int dirfd, const char *restrict pathname, int flags,
          unsigned int mask, struct statx *restrict statxbuf)
{
    *statxbuf = *(&(typeof(*statxbuf)){ 0 });
    statxbuf->stx_mode = S_IFDIR | 0755;
    return 0;
}
EOF
        gcc -shared -fPIC -o "$dir/fake_dir.so" "$dir/fake_dir.c"
    fi
}

frecency()
{
    local topic="$1"; shift
    local db="$HOME/.local/share/zoxide-$topic"
    mkdir -p "$db"

    _ZO_DATA_DIR="$db" \
        LD_PRELOAD="$HOME/.cache/frecency/fake_dir.so" \
        zoxide "$@"
}

ensure_ld_preload_lib_present
frecency "$@"

[wideweide]

That's a fantastic idea!

This seems to perfectly fulfill the functionality I've been wanting to implement recently: vifm/vifm#1144
Two of them can be built in zoxide:

1. Tag history list: This can be more targeted, but it's optional.
2. Open file history list. This is used to directly open files, or to be integrated into a file manager like Vifm to locate files first, and then perform preview, editing, or other operations.

I test the code above then integrated into vifm as Directory/File history list:
vifm/vifm#1144 (comment)

[wideweide]

I gave up and just used SQLite directly as the frecency database.

junegunn/fzf#4789