FZF_DEFAULT_COMMAND utility for fzf

quickfiles

#!/bin/bash

# FZF_DEFAULT_COMMAND utility for fzf
#
# Tries to use Watchman, Ripgrep (rg), The Silver Searcher (ag) in this order.
# ...or falls back the fzf's Unix default.
#
# TODO:
# - Use 'git ls-files -cmod' in Git repositories

has() {
  hash "$1" 2>/dev/null
  return $?
}

can_use_watchman() {
  # When running against fast storage (e.g. ramdisk, PCIe flash, NVMe, etc) it might be worth
  # setting FZF_NO_WATCHMAN.  Both ripgrep (rg) and The Silver Searcher (ag)
  # will be slightly faster than "talk to watchman and parse JSON response".
  if ! (has watchman && has jq) || [[ -n $FZF_NO_WATCHMAN ]]; then
    return 1
  fi

  for WATCHED_ROOT in $(watchman watch-list | jq -r '.roots[]'); do
    SUBDIR="${PWD##$WATCHED_ROOT/}"

    # If expansion worked (above), PWD is a subdirectory of WATCHED_ROOT.
    if [[ ${PWD} != "${SUBDIR}" ]]; then
      return 0
    fi
  done

  return 1
}

use_watchman() {
  local query=$(cat <<EOF
    ["query", "${WATCHED_ROOT}", {
      "path": [{"path": "${SUBDIR}", "depth": -1}],
      "expression": ["allof",
        ["type", "f"],
        ["not", "empty"]
      ],
      "fields": ["name"]
    }]
EOF
  )

  time watchman -j --no-pretty <<< "${query}" > /dev/null
}

use_rg() {
  rg --color auto --files
}

use_ag() {
  ag --nocolor -g '' -l
}

use_fzf_default() {
  # From https://github.com/junegunn/fzf/blob/master/src/constants_unix.go
  find -L . -path '*/\.*' -prune -o -type f -print -o -type l -print 2> /dev/null | sed s/^..//
}


if can_use_watchman; then use_watchman
elif has rg; then use_rg
elif has ag; then use_ag
else use_fzf_default
fi