Implements direnv watch file functionality

fn/-z4h-base64-decode

@@ -0,0 +1,38 @@
+#!/usr/bin/env zsh
+
+eval "$_z4h_opt"
+
+setopt cbases
+
+typeset -g REPLY=
+
+[[ -z $1 ]] && return
+(( $#1 % 4 == 0 )) || return 1
+
+local table='ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/'
+
+local c1 c2 c3 c4 res
+local -i16 b1 b2 b3 b4
+
+for c1 c2 c3 c4 in ${(s::)1//=/A}; do
+  ((
+      b1 = $table[(ie)$c1] - 1,
+      b2 = $table[(ie)$c2] - 1,
+      b3 = $table[(ie)$c3] - 1,
+      b4 = $table[(ie)$c4] - 1,
+      b1 = b1 << 2 | b2 >> 4,
+      b2 = (b2 << 4) & 255 | b3 >> 2,
+      b3 = (b3 << 6) & 255 | b4
+  ))
+  res+=($b1 $b2 $b3)
+done
+
+if [[ $1 == *= ]]; then
+  if [[ $1 == *== ]]; then
+    res[-2,-1]=()
+  else
+    res[-1]=()
+  fi
+fi
+
+printf -v REPLY ${(j:\:)res#0}

fn/-z4h-direnv-hook

@@ -1,5 +1,4 @@
 #!/usr/bin/env zsh
-
 eval "$_z4h_opt"
 
 unset _z4h_direnv_err
@@ -14,33 +13,49 @@ else
   fi
 fi
 
-# { print -n '\x1f\x8b\x08\x00\x00\x00\x00\x00'; base64 -d <<<${${DIRENV_WATCHES//-/+}//_//} } | zcat 2>/dev/null
-
-# zcat
-# gzcat
-# uncompress -c
-# gunzip -c
-# gzip -cd
-
-local sig
+local -a deps
 local envrc=(./(../)#.envrc(NY1:a))
+
 if (( $#envrc )); then
-  local -a deps=(
+  deps+=(
     ${XDG_DATA_HOME:-~/.local/share}/direnv/allow
-    ${XDG_CONFIG_HOME:-~/.config}/{direnv.toml,config.toml})
-  local -a stat
-  local files=($^deps(N))
-  local non_files=(${deps:|files})
-  if zstat -A stat +mtime -- $envrc $files 2>/dev/null; then
-    local sig=$envrc$'\0'${(pj:\0:)stat}
-  else
-    local sig=stat-error
-  fi
-elif [[ ! -v DIRENV_WATCHES ]]; then
+    ${XDG_CONFIG_HOME:-~/.config}/{,direnv/}{direnv.toml,config.toml,direnvrc})
+fi
+
+if [[ -v DIRENV_WATCHES ]]; then
+  () {
+    local REPLY json
+    -z4h-base64-decode ${${DIRENV_WATCHES//-/+}//_//} || return
+    json=$(printf '\x1f\x8b\x08\x00\x00\x00\x00\x00%s' $REPLY | -z4h-zcat 2>/dev/null) #|| return
+    [[ $json == '['*']' ]] || return
+    # TODO: extract $(jq '.[] | .Path') from $json and append it to deps.
+
+    local -i i=1;
+    local pattern=${:-\"Path\":\"([^\"\\\\]|\\\\?)#\"}
+    local pathmatch;
+    pathmatch=${(*MSI:$i:)json##${~pattern}}
+    while [[ -n $pathmatch ]]; do
+      deps+=${(Q)pathmatch##(*):}
+      pathmatch=${(*MSI:$((++i)):)json##${~pattern}}
+    done
+
+    # TODO: cache those elements with $DIRENV_WATCHES as the key.
+  }
+  # TODO: handle errors from the above intelligently.
+fi
+
+if (( $#envrc + $#deps == 0 )); then
   typeset -g _z4h_direnv_sig=none
   return
+fi
+
+local -a stat
+local files=($^deps(N))
+local non_files=(${deps:|files})
+if zstat -A stat +mtime -- $envrc $files 2>/dev/null; then
+  local sig=$envrc$'\0'${(pj:\0:)stat}
 else
-  local sig=none
+  local sig=stat-error
 fi
 
 [[ $sig == ${_z4h_direnv_sig-} ]] && return

fn/-z4h-json-parse

@@ -0,0 +1,85 @@
+#!/usr/bin/env zsh
+# Redneck json parsing. Yields correct results for any well-formed json document.
+# Produces random garbage for invalid json.
+
+local data
+local -a params
+
+data=$1; shift; params=( $@ );
+
+data="${${data//$'\r'}##[[:space:]]#}"
+[[ $data == ('{'|'[')* ]] || return
+if [[ $data == '['*']' ]]
+then
+  local arrayitem=''
+  local -a arraycontents
+  local -i depth=1
+  data[1]=
+  while (( depth > 0 ))
+  do
+    data=${data##[[:space:]]#}
+    [[ -n $data ]] || return
+    case $data[1] in
+      '{'|'[')    arrayitem+=$data[1]; data[1]=; (( ++depth )) ;;
+      '}'|']')    arrayitem+=$data[1]; data[1]=
+                  (( --depth == 1 )) && { arraycontents+=($arrayitem); arrayitem='' } ;;
+      ',')        (( depth == 1 )) || arrayitem+=$data[1];
+                  data[1]= ;;
+      ':')        arrayitem+=$data[1] data[1]=  ;;
+      '"'|[[:alnum:].])
+        if [[ $data[1] == '"' ]]; then
+          local tail=${data##\"([^\"\\]|\\?)#\"}
+        else
+          local tail=${data##[[:alnum:].]#}
+        fi
+        [[ $tail == [[:space:][:punct:]]* ]] || return
+        arrayitem+=${data::-$#tail}; data=${tail}
+        ;;
+      *) return 1 ;;
+    esac
+  done
+  (( ${#data##[[:space:]]#} == 0 )) || return
+  echo $arraycontents
+
+elif [[ $data == '{'*'}' ]]
+then
+  local field
+  local -A found
+  local -i depth=1
+  data[1]=
+  while (( depth > 0 ))
+  do
+    data=${data##[[:space:]]#}
+    [[ -n $data ]] || return
+    case $data[1] in
+      '{'|'[')   data[1]=; (( ++depth )) ;;
+      '}'|']')   data[1]=; (( --depth > 0 )) || return ;;
+      ':')       data[1]=  ;;
+      ',')       data[1]=; field=  ;;
+      '"'|[[:alnum:].])
+        if [[ $data[1] == '"' ]]; then
+          local tail=${data##\"([^\"\\]|\\?)#\"}
+        else
+          local tail=${data##[[:alnum:].]#}
+        fi
+        [[ $tail == [[:space:][:punct:]]* ]] || return
+        local s=${data::-$#tail}
+        data=${tail}
+        (( depth == 1 )) || continue
+        if [[ -z $field ]]; then
+          field=${s:-x}
+        elif [[ $field:*params ]]
+        then
+          (( ! $+found[$field] ))   || return
+          [[ -n $s ]]               || return
+          [[ $s != *($'\n'|'\')* ]] || return
+          found[$field]=$s
+          (( $#found == $#params )) && break
+        fi
+        ;;
+      *) return 1 ;;
+    esac
+  done
+  echo ${(Q)found}
+fi
+

fn/-z4h-zcat

@@ -0,0 +1,11 @@
+#!/usr/bin/env zsh
+
+eval "$_z4h_opt"
+
+local cmd
+for cmd in zcat gzcat 'uncompress -c' 'gunzip -c' 'gzip -cd'; do
+  local words=($=cmd)
+  [[ -v commands[$words[1]] ]] || continue
+  $words || return
+  break
+done